Three-dimensional printed artificial vertebral body versus titanium mesh cage and nanohydroxyapatite/polyamide-66 cage in anterior cervical corpectomy and fusion: a retrospective cohort study with a minimum 5-year follow-up

Three-dimensional printed artificial vertebral body versus titanium mesh cage and nanohydroxyapatite/polyamide-66 cage in anterior cervical corpectomy and fusion: a retrospective cohort study with a minimum 5-year follow-up | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Three-dimensional printed artificial vertebral body versus titanium mesh cage and nanohydroxyapatite/polyamide-66 cage in anterior cervical corpectomy and fusion: a retrospective cohort study with a minimum 5-year follow-up Chunke Dong, Ziyi Zhao, Jun Zhou, Shuai Cao, Wenhao Li, Jiafan Ye, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9025630/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Background: Anterior cervical corpectomy and fusion (ACCF) is a commonly performed procedure for cervical spondylotic myelopathy (CSM), but the choice of reconstructive device after corpectomy remains unsettled. Titanium mesh cages (TMCs) and nanohydroxyapatite/polyamide-66 (n-HA/PA66) cages are both widely used in clinical practice, although subsidence and postoperative loss of cervical alignment remain important concerns. Three-dimensional printed artificial vertebral bodies (3DP-AVBs) have been introduced as an alternative reconstructive option. This study assessed the long-term radiographic and clinical outcomes of 3DP-AVB, n-HA/PA66, and TMC reconstruction after single-level ACCF. Methods: This retrospective cohort study included 101 patients with CSM who underwent single-level ACCF at two centres. Reconstruction was performed using a 3DP-AVB (n = 33), an n-HA/PA66 cage (n = 34), or a TMC (n = 34). Clinical and radiographic data were reviewed with a minimum follow-up of 5 years. Radiographic outcomes included fusion status, subsidence, fused segment height (FSH), and cervical sagittal alignment. Clinical outcomes included the Visual Analog Scale (VAS), Japanese Orthopaedic Association (JOA) score, and Neck Disability Index (NDI). Complications and revision procedures were also recorded. Results: At final follow-up, the 3DP-AVB group had a lower subsidence rate than the n-HA/PA66 and TMC groups (15.2% vs. 32.4% vs. 44.1%; P < 0.001), less loss of FSH (1.99 ± 0.73 vs. 2.80 ± 0.70 vs. 3.07 ± 0.81 mm; P < 0.001), and better preservation of cervical sagittal alignment (C2-7 Cobb angle, 19.47 ± 3.31° vs. 15.19 ± 3.25° vs. 15.75 ± 3.54°; P < 0.001). Fusion was achieved in all patients by 12 months. All three groups improved after surgery. Differences in JOA and NDI were observed at 3 months and remained significant at final follow-up (final JOA, 15.09 ± 1.28 vs. 13.59 ± 1.37 vs. 13.53 ± 1.44; final NDI, 10.03 ± 1.57 vs. 11.88 ± 1.45 vs. 11.88 ± 1.61; both P < 0.001). VAS scores were similar among groups. Conclusions: In patients undergoing single-level ACCF, 3DP-AVB reconstruction was associated with lower subsidence and better maintenance of cervical alignment during long-term follow-up than n-HA/PA66 or TMC reconstruction. All three reconstructive methods achieved fusion and postoperative clinical improvement. Compared with the other two implants, 3DP-AVB may provide greater radiographic durability and may also be associated with better neurological and functional recovery. Further prospective multicentre studies are needed. Trial registration: Not applicable (retrospective cohort). anterior cervical corpectomy and fusion 3D-printed artificial vertebral body titanium mesh cage nanohydroxyapatite/polyamide-66 cage subsidence cervical sagittal alignment Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 1. Introduction Anterior cervical corpectomy and fusion (ACCF) is an established surgical option for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL)[ 1 – 2 ]. By directly removing ventral compressive lesions, it can provide effective decompression of the spinal cord and may result in satisfactory neurological recovery in appropriately selected patients[ 3 ]. Nevertheless, reconstruction after corpectomy remains challenging, particularly because graft-related complications and postoperative loss of sagittal alignment may still occur[ 4 ]. The reconstructive strategy used in anterior cervical surgery has gradually changed over time. Autologous iliac crest bone grafting was historically regarded as the standard method, but donor-site morbidity limited its wider acceptance[ 5 ]. Cage-based reconstruction was subsequently adopted to avoid graft harvest. Titanium mesh cages (TMCs) reduced donor-site complications, yet implant subsidence remained a persistent concern. Nanohydroxyapatite/polyamide-66 (n-HA/PA66) cages were later introduced because of their osteoconductive properties, although radiographic height loss and interface-related problems have not been completely eliminated[ 6 ]. Advances in additive manufacturing have enabled the clinical use of three-dimensional printed artificial vertebral bodies (3DP-AVBs). Their porous architecture can be adjusted to better approximate the mechanical behavior of native bone while also facilitating osseointegration[ 7 – 9 ]. From a theoretical perspective, this design may reduce elastic modulus mismatch, improve load transfer, and support more stable implant-bone integration. Although these implants are increasingly used in cervical reconstruction, direct comparisons among TMCs, n-HA/PA66 cages, and 3DP-AVBs remain limited. The present retrospective cohort study was therefore performed to compare the long-term radiographic and clinical outcomes of these three reconstructive options after single-level ACCF. We expected that 3DP-AVB would show better radiographic performance, particularly in terms of subsidence control and maintenance of cervical sagittal alignment. 2. Methods 2.1 Study design, aim, and setting This retrospective cohort study was conducted at the Departments of Spinal Surgery of China-Japan Friendship Hospital and Beijing Hospital of Traditional Chinese Medicine (Beijing, China), from September 2016 to September 2020. The study was approved by the institutional ethics committees of both hospitals. Written informed consent was waived because of the retrospective design, in accordance with national regulations and institutional requirements. 2.2 Participants Consecutive patients who underwent single-level anterior cervical corpectomy and fusion (ACCF) for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) during the study period were screened for inclusion. The inclusion criteria were: (1) age 18–80 years; (2) diagnosis confirmed by magnetic resonance imaging (MRI) and computed tomography (CT); (3) complete clinical and radiographic data; and (4) a minimum follow-up of 60 months. The exclusion criteria were: multilevel corpectomy, previous cervical surgery, traumatic or infectious pathology, severe osteoporosis (T-score < − 2.5 on dual-energy X-ray absorptiometry), and systemic or psychiatric disorders that might affect outcome assessment. 2.3 Surgical procedure All procedures were performed by a senior spine surgeon with more than 15 years of surgical experience. A standardized right-sided Smith-Robinson anterior cervical approach was used[ 10 ]. After complete corpectomy, the endplates were prepared carefully with curettes to preserve the subchondral bony structure while removing the cartilaginous endplate. Implant size was selected intraoperatively to obtain an appropriate fit without excessive distraction. Autologous bone harvested from the resected vertebral body was morselized and tightly packed into the implant. Patients in the 3DP-AVB group received a 3D-printed artificial vertebral body (Beijing AK Medical Co., Ltd., Beijing, China), with implant dimensions selected according to intraoperative measurements. The n-HA/PA66 group received nanohydroxyapatite/polyamide-66 cages (Sichuan National Nano Science and Technology Co., Ltd., Chengdu, China). The TMC group received titanium mesh cages (Fule Science & Technology Development Co., Ltd., Beijing, China), which were trimmed intraoperatively to improve endplate conformity (Fig. 1 ). An anterior cervical plate was applied in all patients. After surgery, all patients wore a rigid cervical collar for 12 weeks. 2.4 Outcome assessment The primary radiographic outcomes included fused segment height (FSH), implant subsidence, the C2-7 Cobb angle measured on standing lateral radiographs, and fusion status at 12 months (Fig. 2 ). Subsidence was defined as a decrease of 3 mm or more in FSH compared with the immediate postoperative measurement. Fusion was evaluated using the available postoperative imaging. Initial assessment was based on anteroposterior and lateral cervical radiographs. Fusion was considered present when continuous bridging bone crossed the operated segment and no radiolucent gap was identified between the grafted area and the adjacent vertebral endplates[ 11 ]. When plain radiographs were inconclusive, CT with sagittal and coronal reconstruction was reviewed. Fusion was then confirmed when continuous bridging bone, particularly extragraft bridging bone, was seen across the operated segment without intervening lucency[ 12 ]. Secondary outcomes were clinical measures, including the Visual Analog Scale (VAS; 0–10) for neck and arm pain, the Japanese Orthopaedic Association (JOA) score (0–17) for myelopathy severity, and the Neck Disability Index (NDI; 0–50) for functional impairment. Assessments were performed preoperatively and at 3 months and the final follow-up (≥ 60 months). 2.5 Radiographic assessment Radiographic measurements were independently performed by two spine surgeons, both blinded to the clinical outcomes. Interobserver reliability was evaluated using intraclass correlation coefficients, and all ICC values were greater than 0.85. Subsidence was quantified as the change in the vertical distance between the inferior endplate of the cranial vertebra and the superior endplate of the caudal vertebra at the operated level[ 13 ]. 2.6 Statistical analysis All statistical analyses were performed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). Continuous variables are presented as mean ± standard deviation and were compared using one-way analysis of variance (ANOVA) with Tukey's post hoc test, or the Kruskal-Wallis test when appropriate. Categorical variables are expressed as frequencies and were compared using the chi-square test or Fisher's exact test. All tests were two-sided, and P < 0.05 was considered statistically significant. Because this was a retrospective study, no a priori sample size calculation was performed; the final sample size was determined by the number of eligible patients available during the study period. 3. Results 3.1 Patient demographics A total of 101 patients met the inclusion criteria, including 34 in the TMC group, 34 in the n-HA/PA66 group, and 33 in the 3DP-AVB group. The baseline demographic and preoperative characteristics, including age, sex, BMI, bone mineral density (BMD), duration of follow-up and the operated level, were comparable among the three groups. The operative parameters also varied significantly across the groups. The 3DP-AVB group had the shortest operative time (97.70 ± 11.29 min), followed by the TMC group (110.15 ± 8.86 min) and the n-HA/PA66 group (118.41 ± 11.20 min) (P < 0.001). Similarly, intraoperative blood loss was lowest in the 3DP-AVB group (86.61 ± 8.43 mL), followed by the n-HA/PA66 group (91.62 ± 10.17 mL) and the TMC group (96.71 ± 11.67 mL) (P < 0.001; Table 1 ). Table 1 Baseline Demographic, Clinical, and Perioperative Characteristics of the Three Groups Characteristic 3DP-AVB (n = 33) n-HA/PA66 (n = 34) TMC (n = 34) P value Age (years) 57.15 ± 6.96 54.35 ± 6.21 55.32 ± 7.73 0.257 Sex (M/F) 20/13 17/17 18/16 0.668 BMI (kg/m²) 23.57 ± 2.44 24.66 ± 2.24 23.56 ± 2.20 0.080 BMD (T-score) -0.50 ± 0.31 -0.44 ± 0.33 -0.37 ± 0.36 0.303 Blood loss (mL) 86.61 ± 8.43 91.62 ± 10.17 96.71 ± 11.67 < 0.001 Operative time (min) 97.70 ± 11.29 118.41 ± 11.20 110.15 ± 8.86 < 0.001 Follow-up duration (months) 80.73 ± 15.54 76.00 ± 12.69 73.18 ± 15.85 0.106 Operated level, n (%) 0.467 C3 1(3.0) 2(5.9) 2(5.9) C4 8(24.2) 3(8.8) 8(23.5) C5 14(42.4) 18(52.9) 18(52.9) C6 10(30.3) 11(32.4) 6(17.6) 3.2 Radiographic outcomes The 3DP-AVB group demonstrated superior radiographic outcomes compared with the n-HA/PA66 and TMC groups. Specifically, the 3DP-AVB group had the lowest subsidence rate (15.2% vs. 32.4% vs. 44.1%, P < 0.001) and the smallest loss of fused segment height (1.99 ± 0.73 mm vs. 2.80 ± 0.70 mm vs. 3.07 ± 0.81 mm, P < 0.001). In addition, cervical sagittal alignment was better preserved in the 3DP-AVB group, which showed a significantly greater C2–7 Cobb angle at final follow-up than the n-HA/PA66 and TMC groups (19.47 ± 3.31° vs. 15.19 ± 3.25° vs. 15.75 ± 3.54°, P < 0.001) (Figs. 3 – 5 ). Fusion was achieved in all patients by 12 months, resulting in a 100% fusion rate in all three groups (Fig. 9 – 13 ). 3.3 Clinical outcomes All three groups showed significant postoperative improvement in JOA, NDI, and VAS scores. Baseline clinical scores were comparable among the groups, including preoperative JOA, NDI, and VAS scores (P = 0.156, P = 0.551, and P = 0.093, respectively). At 3 months postoperatively, significant between-group differences were observed in JOA and NDI scores (P = 0.022 and P = 0.002, respectively), whereas VAS scores remained comparable across the groups (P = 0.952). These between-group differences in JOA and NDI persisted at the final follow-up. The 3DP-AVB group showed the highest final JOA score (15.09 ± 1.28), compared with the n-HA/PA66 group (13.59 ± 1.37) and the TMC group (13.53 ± 1.44) (P < 0.001). The 3DP-AVB group also showed the lowest final NDI score (10.03 ± 1.57), compared with the n-HA/PA66 group (11.88 ± 1.45) and the TMC group (11.88 ± 1.61) (P < 0.001). Final VAS scores remained comparable among groups (P = 0.864) (Figs. 6 – 8 ). 3.4 Complications No infections, cerebrospinal fluid leakage, or perioperative deaths were observed (Table 2 ). The most common complications were transient dysphagia and adjacent segment disease (ASD) requiring revision. Dysphagia occurred in 6.1%, 8.8%, and 14.7% of patients in the 3DP-AVB, n-HA/PA66, and TMC groups, respectively, with no significant between-group difference (P = 0.480). Hoarseness or recurrent laryngeal nerve palsy was observed in 3.0%, 5.9%, and 11.8% of patients, respectively (P = 0.356). ASD was numerically more frequent in the TMC group (8.8%) than in the 3DP-AVB group (3.0%) or the n-HA/PA66 group (2.9%), although the difference was not statistically significant (P = 0.442). Table 2 Postoperative Complications During Follow-Up Complication 3DP-AVB (n = 33) n (%) n-HA/PA66 (n = 34) n (%) TMC (n = 34) n (%) P value Infection 0 (0) 0 (0) 0 (0) - Dysphagia 2 (6.1) 3 (8.8) 5 (14.7) 0.480 Hoarseness / recurrent laryngeal nerve palsy 1 (3.0) 2 (5.9) 4 (11.8) 0.356 CSF leakage 0 (0) 0 (0) 0 (0) - New/worsened neurological deficit 0 (0) 0 (0) 0 (0) - Adjacent Segment Disease (ASD) 1 (3.0) 1 (2.9) 3 (8.8) 0.442 4. Discussion In the present cohort, reconstruction with 3DP-AVB was associated with more stable radiographic findings over long-term follow-up than reconstruction with either n-HA/PA66 cages or TMCs after single-level ACCF. The main differences were observed in subsidence, fused segment height loss, and maintenance of cervical sagittal alignment. At the same time, all three implants achieved fusion and were associated with postoperative clinical improvement. These findings suggest that the main advantage of 3DP-AVB lies in preservation of structural support over time rather than in uniform superiority across all measured outcomes. Earlier comparative studies have also reported improved structural stability and radiographic maintenance with 3D-printed vertebral body devices in anterior cervical reconstruction[ 7 – 9 , 14 ]. The present study adds longer-term follow-up to that body of evidence, showing that the radiographic differences remained evident after at least 5 years. In clinical terms, successful reconstruction depends not only on immediate postoperative stability, but also on preservation of segmental height and alignment throughout the later healing period. Subsidence remains a major concern after ACCF because it may lead to loss of segmental height, local malalignment, and progressive reduction in construct stability during follow-up[ 13 , 16 ]. Previous biomechanical studies have shown that implant geometry, endplate matching, and stress distribution at the bone-implant interface play important roles in this process[ 19 , 20 ]. Clinical and radiographic studies have similarly linked these factors to height loss and late radiographic deterioration[ 21 , 22 ]. From this perspective, the lower subsidence rate in the 3DP-AVB group is more likely to reflect implant-specific structural characteristics that improve load transfer and reduce stress concentration at the adjacent endplates. The comparison with n-HA/PA66 cages is also informative. Previous clinical studies have suggested that n-HA/PA66 cages may perform better than TMCs with respect to subsidence and radiographic maintenance[ 21 , 22 , 29 ], although loss of height and interface-related radiographic changes may still occur[ 28 , 32 ]. A similar pattern was observed in the present study: the n-HA/PA66 group performed better than the TMC group in several radiographic measures, but remained inferior to the 3DP-AVB group. This gradient across the three implants indicates that the outcome of ACCF reconstruction depends not only on whether fusion is eventually achieved, but also on how well structural support is maintained while fusion is taking place. Comparative evidence in ACCF has increasingly pointed toward a radiographic advantage for 3DP-AVB. Wei et al. reported in a prospective randomized cohort that 3DP-AVBs were associated with less subsidence and better preservation of cervical lordosis than TMCs[ 7 ]. Fang et al. and He et al. also described advantages in fused segment height and alignment preservation[ 8 , 9 ]. More recent comparative studies have shown similar trends in different cohorts[ 14 , 15 ]. In addition, mechanical studies have demonstrated that newer 3D-printed titanium cage designs may provide stronger resistance to subsidence than conventional titanium cages[ 23 , 25 ]. These biomechanical observations offer a plausible explanation for the present radiographic findings. One practical advantage of 3D printing is the ability to control implant geometry, pore size, and overall porosity with greater precision[ 25 – 28 ]. Porous titanium constructs can therefore be designed to better balance mechanical strength and elastic modulus, which may reduce stiffness mismatch and improve load transfer at the bone-implant interface[ 27 – 29 ]. Such structural optimization may account, at least in part, for the lower subsidence rate and better maintenance of sagittal alignment observed in the 3DP-AVB group. In this setting, durable reconstruction depends not only on fusion itself, but also on the mechanical interaction between the implant and the adjacent endplates. Long-term implant behavior is influenced not only by mechanical support, but also by biological fixation. Although n-HA/PA66 constructs can achieve high fusion rates, previous studies have described interface-related radiographic findings, including radiolucent gaps, suggesting that osseointegration may not always be optimal[ 28 , 32 ]. In contrast, the interconnected porous structure of 3DP-AVB may provide a more favorable scaffold for bone ingrowth and implant-bone integration[ 23 , 30 , 31 ]. This difference in biological behavior may have contributed to the more durable radiographic performance observed in the present cohort. All three groups demonstrated substantial postoperative clinical improvement, indicating that adequate decompression and reconstruction were achieved regardless of implant type. However, recovery was not identical across all clinical measures. Differences among groups were observed for JOA and NDI at 3 months and remained evident at final follow-up, whereas VAS scores were comparable. This pattern suggests that the potential clinical benefit associated with 3DP-AVB may be more apparent in neurological recovery and functional improvement than in pain relief alone. The lack of consistent differences across all clinical outcomes should be interpreted cautiously. Recovery after ACCF is influenced by multiple factors, including preoperative neurological status, adequacy of decompression, postoperative rehabilitation, and other patient-related variables in addition to implant characteristics[ 33 ]. As a result, implant selection may have a more direct influence on radiographic durability than on symptom relief itself. Even so, preservation of cervical sagittal alignment may still be clinically relevant, because postoperative sagittal parameters have been associated with functional outcomes after anterior cervical surgery[ 34 ]. The complication profile was acceptable in all three groups, and no infection, cerebrospinal fluid leakage, or perioperative death was observed. The most frequent complications were transient dysphagia, hoarseness or recurrent laryngeal nerve-related symptoms, and adjacent segment disease requiring revision. Although these events were numerically more common in the TMC group, the between-group differences were not statistically significant. This finding is consistent with earlier reports indicating that complications after anterior cervical corpectomy remain clinically relevant and may be influenced by both construct stability and the technical demands of reconstruction[ 17 – 19 ]. Given the modest sample size, any possible relationship between improved endplate matching and a lower complication rate should be interpreted with caution. 4.1 Limitations This study has several limitations. First, because of its retrospective design, selection bias and residual confounding cannot be completely excluded, and implant selection may have been influenced by surgeon preference, implant availability, or changes in practice over time. Second, the sample size was relatively small, which may have reduced statistical power, particularly for complication-related comparisons and more fully adjusted analyses. Third, only single-level ACCF cases were included; therefore, extrapolation of the present findings to multilevel procedures, revision surgery, severe osteoporosis, or other complex reconstructive settings should be cautious. Finally, although the minimum 5-year follow-up strengthens the longitudinal value of the study, longer observation is still needed to clarify implant durability, adjacent segment degeneration, and the clinical relevance of better radiographic preservation over time. Larger prospective multicentre studies are needed to confirm these observations and further define the indications for 3DP-AVB reconstruction. 4.2 Clinical implications The present findings are relevant to implant selection in ACCF reconstruction. When several reconstructive options are available, 3DP-AVB may be considered for patients who are thought to be at greater risk of subsidence or postoperative loss of alignment, particularly when endplate support and load distribution are major concerns. More broadly, these results indicate that implant selection after ACCF should not be judged by fusion status alone, but also by how well structural stability is preserved during follow-up. From this perspective, 3DP-AVB may be particularly useful when long-term radiographic maintenance is a major surgical priority. Prospective multicentre studies are still required to further clarify its indications[ 41 ]. 5. Conclusions In this retrospective cohort with a minimum follow-up of 5 years, 3DP-AVB reconstruction was associated with less subsidence and better maintenance of cervical alignment than n-HA/PA66 or TMC reconstruction after single-level ACCF. All three reconstructive methods achieved fusion and were followed by postoperative clinical improvement. Compared with the radiographic findings, the clinical differences were less consistent: JOA and NDI favored 3DP-AVB, whereas VAS scores were similar among groups. Overall, these findings indicate that 3DP-AVB may offer better long-term radiographic durability after single-level ACCF, with possible advantages in neurological and functional recovery. Further prospective multicentre studies are required for confirmation. Abbreviations ACCF: anterior cervical corpectomy and fusion 3DP-AVB: three-dimensional printed artificial vertebral body n-HA/PA66: nanohydroxyapatite/polyamide-66 TMC: titanium mesh cage ASD: adjacent segment disease BMD: bone mineral density BMI: body mass index CSF: cerebrospinal fluid CSM: cervical spondylotic myelopathy CT: computed tomography FSH: fused segment height ICC: intraclass correlation coefficient JOA: Japanese Orthopaedic Association MRI: magnetic resonance imaging NDI: Neck Disability Index OPLL: ossification of the posterior longitudinal ligament SD: standard deviation VAS: Visual Analog Scale Declarations Ethical Approval This study was approved by the Ethics Committees of both China-Japan Friendship Hospital and Beijing Hospital of Traditional Chinese Medicine. The requirement for written informed consent was waived due to the retrospective nature of the study, in accordance with national ethical regulations. Funding This work was supported by the Beijing Capital Health Development Research Special Project (Grant No. 2024-2-2233). Competing Interests The authors declare that they have no competing interests. Availability of Data and Materials The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. References Zhang AS, Myers C, McDonald CL, Alsoof D, Anderson G, Daniels AH. Cervical Myelopathy: Diagnosis, Contemporary Treatment, and Outcomes. Am J Med. 2022;135(4):435–43. Epub 2021 Nov 30. PMID: 34861202. Ghogawala Z. Anterior Cervical Option to Manage Degenerative Cervical Myelopathy. Neurosurg Clin N Am. 2018;29(1):83–89. 10.1016/j.nec.2017.09.005 . PMID: 29173439. Huang D, Du X, Liang H, Hu W, Hu H, Cheng X. Anterior corpectomy versus posterior laminoplasty for the treatment of multilevel cervical myelopathy: A meta-analysis. Int J Surg. 2016;35:21–7. 10.1016/j.ijsu.2016.09.008 . Epub 2016 Sep 10. PMID: 27622728. Wang S, Xiang Y, Wang X, Li H, Hou Y, Zhao H, Pan X. Anterior corpectomy comparing to posterior decompression surgery for the treatment of multi-level ossification of posterior longitudinal ligament: A meta-analysis. Int J Surg. 2017;40:91–6. Epub 2017 Feb 22. PMID: 28254423. Sawin PD, Traynelis VC, Menezes AH. A comparative analysis of fusion rates and donor-site morbidity for autogeneic rib and iliac crest bone grafts in posterior cervical fusions. J Neurosurg. 1998;88(2):255 – 65. doi: 10.3171/jns.1998.88.2.0255. PMID: 9452233. Zhong W, Liang X, Tang K, Luo X, Quan Z, Jiang D. Nanohydroxyapatite/polyamide 66 strut subsidence after one-level corpectomy: underlying mechanism and effect on cervical neurological function. Sci Rep. 2018;8(1):12098. 10.1038/s41598-018-30678-1 . PMID: 30108277; PMCID: PMC6092369. Wei F, Xu N, Li Z, Cai H, Zhou F, Yang J, Yu M, Liu X, Sun Y, Zhang K, Pan S, Wu F, Liu Z. A prospective randomized cohort study on 3D-printed artificial vertebral body in single-level anterior cervical corpectomy for cervical spondylotic myelopathy. Ann Transl Med. 2020;8(17):1070. 10.21037/atm-19-4719 . PMID: 33145289; PMCID: PMC7575998. Fang T, Zhang M, Yan J, Zhao J, Pan W, Wang X, Zhou Q. Comparative Analysis of 3D-Printed Artificial Vertebral Body Versus Titanium Mesh Cage in Repairing Bone Defects Following Single-Level Anterior Cervical Corpectomy and Fusion. Med Sci Monit. 2021;27:e928022. 10.12659/MSM.928022 . PMID: 33550326; PMCID: PMC7876950. He H, Fan L, Lü G, Li X, Li Y, Zhang O, Chen Z, Yuan H, Pan C, Wang X, Kuang L. Myth or fact: 3D-printed off-the-shelf prosthesis is superior to titanium mesh cage in anterior cervical corpectomy and fusion? BMC Musculoskelet Disord. 2024;25(1):96. 10.1186/s12891-024-07213-7 . PMID: 38279132; PMCID: PMC10811816. SMITH GW, ROBINSON RA. The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. J Bone Joint Surg Am. 1958;40–A(3):607–24. PMID: 13539086. Lee J, Lee DH, Jung CW, Song KS. The Significance of Extra-Cage Bridging Bone via Radiographic Lumbar Interbody Fusion Criterion. Global Spine J. 2023;13(1):113–21. doi: 10.1177/2192568221993097. Epub 2021 Feb 18. PMID: 33596702; PMCID: PMC9837518. Song KS, Chaiwat P, Kim HJ, Mesfin A, Park SM, Riew KD. Anterior cervical fusion assessment using reconstructed computed tomographic scans: surgical confirmation of 254 segments. Spine (Phila Pa 1976). 2013;38(25):2171-7. 10.1097/BRS.0000000000000017 . PMID: 24048090. Tang Y, Geng X, Li F, Sun Y, Jia L, Zhou S, Chen X. Factors affecting titanium mesh cage subsidence in single-level anterior cervical corpectomy and fusion for ossification of the posterior longitudinal ligament. J Orthop Surg Res. 2022;17(1):515. 10.1186/s13018-022-03409-6 . PMID: 36457100; PMCID: PMC9714211. Wang H, Qu R, Xia T, Geng H, Yi Z, Sun Y, Zhang F, Pan S, Chen X, Zhao Y, Liu Z, Zhou F. Artificial vertebral body versus titanium mesh cage for single-level anterior cervical corpectomy and fusion (ACCF): a propensity score matching analysis of fusion, implant subsidence and clinical outcomes. BMC Musculoskelet Disord. 2025;26(1):1060. 10.1186/s12891-025-09308-1 . PMID: 41257777; PMCID: PMC12628911. Li J, Zhang J, Wang B, Huang K, Yang X, Song Y, Liu H, Rong X. Spine (Phila Pa 1976). 2025;50(2):88–95. Epub 2024 Aug 23. PMID: 39175433. Comparison of Titanium Mesh Cage, Nano-Hydroxyapatite/Polyamide Cage, and Three-Dimensional-Printed Vertebral Body for Anterior Cervical Corpectomy and Fusion. Ruomu Q, Haoxiang W, Tian X, Hanbo G, Yanbin Z, Yinze D, Xin C, Shengfa P, Li Z, Shaobo W, Fengshan Z, Yu S, Zhong Jun L, Feifei Z. Risk factors of early subsidence of 3D-printed artificial vertebral body following single-level anterior cervical corpectomy and fusion (ACCF): retrospective study of 98 patients. J Orthop Surg Res. 2025;20(1):633. 10.1186/s13018-025-06056-9 . PMID: 40635074; PMCID: PMC12243176. Hee HT, Majd ME, Holt RT, Whitecloud TS 3rd, Pienkowski D. Complications of multilevel cervical corpectomies and reconstruction with titanium cages and anterior plating. J Spinal Disord Tech. 2003;16(1):1–8; discussion 8–9. 10.1097/00024720-200302000-00001 . PMID: 12571477. Hirai T, Yoshii T, Sakai K, Inose H, Yuasa M, Yamada T, Matsukura Y, Ushio S, Morishita S, Egawa S, Onuma H, Kobayashi Y, Utagawa K, Hashimoto J, Kawabata A, Tanaka T, Motoyoshi T, Takahashi T, Hashimoto M, Sakaeda K, Kato T, Arai Y, Kawabata S, Okawa A. Anterior Cervical Corpectomy with Fusion versus Anterior Hybrid Fusion Surgery for Patients with Severe Ossification of the Posterior Longitudinal Ligament Involving Three or More Levels: A Retrospective Comparative Study. J Clin Med. 2021;10(22):5315. 10.3390/jcm10225315 . PMID: 34830602; PMCID: PMC8624558. Zhou E, Huang H, Zhao Y, Wang L, Fan Y. The effects of titanium mesh cage size on the biomechanical responses of cervical spine after anterior cervical corpectomy and fusion: A finite element study. Clin Biomech (Bristol). 2022;91:105547. Epub 2021 Dec 13. PMID: 34923190. Zhang KR, Yang Y, Ma LT, Qiu Y, Wang BY, Ding C, Meng Y, Rong X, Hong Y, Liu H. Biomechanical Effects of a Novel Anatomic Titanium Mesh Cage for Single-Level Anterior Cervical Corpectomy and Fusion: A Finite Element Analysis. Front Bioeng Biotechnol. 2022;10:881979. 10.3389/fbioe.2022.881979 . PMID: 35814021; PMCID: PMC9263189. Hu B, Wang L, Song Y, Hu Y, Lyu Q, Liu L, Zhu C, Zhou C, Yang X. A comparison of long-term outcomes of nanohydroxyapatite/polyamide-66 cage and titanium mesh cage in anterior cervical corpectomy and fusion: A clinical follow-up study of least 8 years. Clin Neurol Neurosurg. 2019;176:25–9. Epub 2018 Nov 19. PMID: 30481654. Zhong W, Liang X, Luo X, Quan Z, Jiang D. Imaging evaluation of nano-hydroxyapatite/polyamide 66 strut in cervical construction after 1-level corpectomy: a retrospective study of 520 patients. Eur J Med Res. 2020;25(1):38. 10.1186/s40001-020-00440-3 . PMID: 32873339; PMCID: PMC7466497. Yang H, Wang Y, Miao J, Wang J, Li H, Zhang Y, Yan L, Wang B. Analysis of the anti-subsidence mechanical properties of novel 3D-printed titanium cages compared to conventional titanium cages. J Orthop Surg Res. 2025;20(1):854. 10.1186/s13018-025-06237-6 . PMID: 41013548; PMCID: PMC12465666. Kiselev R, Zheravin A. Clinical Application of 3D-Printed Artificial Vertebral Body (3DP AVB): A Review. J Pers Med. 2024;14(10):1024. 10.3390/jpm14101024 . PMID: 39452532; PMCID: PMC11508315. Li L, Shi J, Zhang K, Yang L, Yu F, Zhu L, Liang H, Wang X, Jiang Q. Early osteointegration evaluation of porous Ti6Al4V scaffolds designed based on triply periodic minimal surface models. J Orthop Translat. 2019;19:94–105. PMID: 31844617; PMCID: PMC6896722. Parthasarathy J, Starly B, Raman S, Christensen A. Mechanical evaluation of porous titanium (Ti6Al4V) structures with electron beam melting (EBM). J Mech Behav Biomed Mater. 2010;3(3):249–59. 10.1016/j.jmbbm.2009.10.006 . Epub 2009 Oct 22. PMID: 20142109. Taniguchi N, Fujibayashi S, Takemoto M, Sasaki K, Otsuki B, Nakamura T, Matsushita T, Kokubo T, Matsuda S. Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: An in vivo experiment. Mater Sci Eng C Mater Biol Appl. 2016;59:690–701. Epub 2015 Oct 28. PMID: 26652423. Li JX, Peng HT, Chen ZY, Hu CB, He T, Li H, Quan ZX. Insight Into Osseointegration of Nanohydroxyapatite/Polyamide 66 Based on the Radiolucent Gap: Comparison With Polyether-Ether-Ketone. Front Mater. 2021;8:678550. 10.3389/fmats.2021.678550 . Zhang Y, Deng X, Jiang D, Luo X, Tang K, Zhao Z, Zhong W, Lei T, Quan Z. Long-term results of anterior cervical corpectomy and fusion with nano-hydroxyapatite/polyamide 66 strut for cervical spondylotic myelopathy. Sci Rep. 2016;6:26751. 10.1038/srep26751 . PMID: 27225189; PMCID: PMC4880938. Spece H, Basgul C, Andrews CE, MacDonald DW, Taheri ML, Kurtz SM. A systematic review of preclinical in vivo testing of 3D printed porous Ti6Al4V for orthopedic applications, part I: Animal models and bone ingrowth outcome measures. J Biomed Mater Res B Appl Biomater. 2021;109(10):1436–54. 10.1002/jbm.b.34803 . Epub 2021 Jan 22. PMID: 33484102. Lewallen EA, Riester SM, Bonin CA, Kremers HM, Dudakovic A, Kakar S, Cohen RC, Westendorf JJ, Lewallen DG, van Wijnen AJ. Biological strategies for improved osseointegration and osteoinduction of porous metal orthopedic implants. Tissue Eng Part B Rev. 2015;21(2):218–30. Epub 2014 Dec 18. PMID: 25348836; PMCID: PMC4390115. Zhang Y, Quan Z, Zhao Z, Luo X, Tang K, Li J, Zhou X, Jiang D. Evaluation of anterior cervical reconstruction with titanium mesh cages versus nano-hydroxyapatite/polyamide66 cages after 1- or 2-level corpectomy for multilevel cervical spondylotic myelopathy: a retrospective study of 117 patients. PLoS ONE. 2014;9(5):e96265. 10.1371/journal.pone.0096265 . PMID: 24789144; PMCID: PMC4008500. Wang X, Huang D, Han J, Luo J, Wang Y. Mid-Term Functional Recovery After ACDF and ACCF in the Treatment of Adjacent Two-Level Cervical Spondylosis: A Comparative Study. J Pain Res. 2025;18:3009–16. PMID: 40546827; PMCID: PMC12182085. Fan XW, Wang ZW, Gao XD, Ding WY, Yang DL. The change of cervical sagittal parameters plays an important role in clinical outcomes of cervical spondylotic myelopathy after multi-level anterior cervical discectomy and fusion. J Orthop Surg Res. 2019;14(1):429. 10.1186/s13018-019-1504-3 . PMID: 31829200; PMCID: PMC6907178. Zhang T, Li J, Li X, Pan X, Gao X, Yang X, Ma X, Li H, Feng S, Liu Z. An innovative self-stabilised 3D-printed artificial vertebral body designed for clinical application and comparison with the conventional implants. J Orthop Translat. 2025;53:52–62. PMID: 40529899; PMCID: PMC12173030. Meng M, Wang J, Sun T, Zhang W, Zhang J, Shu L, Li Z. Clinical applications and prospects of 3D printing guide templates in orthopaedics. J Orthop Translat. 2022;34:22–41. PMID: 35615638; PMCID: PMC9117878. Jing Z, Zhang T, Xiu P, Cai H, Wei Q, Fan D, Lin X, Song C, Liu Z. Functionalization of 3D-printed titanium alloy orthopedic implants: a literature review. Biomed Mater. 2020;15(5):052003. 10.1088/1748-605X/ab9078 . PMID: 32369792. Wang X, Guo Q, He Y, Geng X, Wang C, Li Y, Li Z, Wang C, Qiu D, Tian H. A pH-neutral bioactive glass coated 3D-printed porous Ti6Al4V scaffold with enhanced osseointegration. J Mater Chem B. 2023;11(6):1203–1212. 10.1039/d2tb02129c . PMID: 36515141. Zhang H, Wu Z, Wang Z, Yan X, Duan X, Sun H. Advanced surface modification techniques for titanium implants: a review of osteogenic and antibacterial strategies. Front Bioeng Biotechnol. 2025;13:1549439. doi: 10.3389/fbioe.2025.1549439. Erratum in: Front Bioeng Biotechnol. 2025;13:1629360. 10.3389/fbioe.2025.1629360 . PMID: 40177619; PMCID: PMC11962728. Llopis-Grimalt MA, Arbós A, Gil-Mir M, Mosur A, Kulkarni P, Salito A, Ramis JM, Monjo M. Multifunctional Properties of Quercitrin-Coated Porous Ti-6Al-4V Implants for Orthopaedic Applications Assessed In Vitro. J Clin Med. 2020;9(3):855. 10.3390/jcm9030855 . PMID: 32245053; PMCID: PMC7141521. Mok SW, Nizak R, Fu SC, Ho KK, Qin L, Saris DBF, Chan KM, Malda J. From the printer: Potential of three-dimensional printing for orthopaedic applications. J Orthop Translat. 2016;6:42–9. PMID: 30035082; PMCID: PMC5987023. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 17 May, 2026 Reviewers agreed at journal 04 May, 2026 Reviewers agreed at journal 04 May, 2026 Reviewers invited by journal 27 Apr, 2026 Editor assigned by journal 07 Mar, 2026 Submission checks completed at journal 07 Mar, 2026 First submitted to journal 03 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9025630","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":634125763,"identity":"e09cf6fc-f5e0-4e9c-86cc-65147472f30e","order_by":0,"name":"Chunke Dong","email":"","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Chunke","middleName":"","lastName":"Dong","suffix":""},{"id":634125765,"identity":"3c908b66-7fbf-42a9-89c1-ffd84d81b57c","order_by":1,"name":"Ziyi Zhao","email":"","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Ziyi","middleName":"","lastName":"Zhao","suffix":""},{"id":634125766,"identity":"2a4e7468-0c53-4216-8b08-7ab09bdde141","order_by":2,"name":"Jun Zhou","email":"","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Zhou","suffix":""},{"id":634125769,"identity":"9c17dbba-01ef-4cfc-a29a-d11993e0eccc","order_by":3,"name":"Shuai Cao","email":"","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Shuai","middleName":"","lastName":"Cao","suffix":""},{"id":634125772,"identity":"78e10537-4c40-47b0-a94d-c0737ae82b56","order_by":4,"name":"Wenhao Li","email":"","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Wenhao","middleName":"","lastName":"Li","suffix":""},{"id":634125775,"identity":"cf7da1ef-9d02-40bb-a84e-e30d2f24f9a6","order_by":5,"name":"Jiafan Ye","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYBACxmYGhg8gBj+IeMDAYECMFsYZIIZkAwNjQwIxWkC6wFoMDhCrhbmd+WHDzx2H5YyP95g/SKiwMWZgP3x0A36HsRk29p45bGx25oxhQ8KZNDMGnrS0GwT8Yv6At+1w4rYbOYYNiW2HbRgkeMwIaGH/2Pi37XD95hnEa+ExbAbakmAgAdFiRoyWwmbZtnTDGWeOFc4A+sWYjZBfDPuPb2x822Ytz9/evOHDhwobw372w8fwa2kAU80IETZ8ykFAHkLVEVI3CkbBKBgFIxkAAPsVTjGPrmMYAAAAAElFTkSuQmCC","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":true,"prefix":"","firstName":"Jiafan","middleName":"","lastName":"Ye","suffix":""},{"id":634125779,"identity":"8a6013ee-c058-4bf2-8a6f-e4c9a76436c4","order_by":6,"name":"Hongyu Wei","email":"","orcid":"","institution":"Beijing Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Hongyu","middleName":"","lastName":"Wei","suffix":""}],"badges":[],"createdAt":"2026-03-04 04:24:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9025630/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9025630/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108939304,"identity":"025b6f61-c5b4-4fc7-a213-b6f44ad52851","added_by":"auto","created_at":"2026-05-11 05:07:04","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":405160,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative reconstructive implants used in this study\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/8a2903cd41f192c800a1f1bf.png"},{"id":108977919,"identity":"4c7835dd-8e10-4291-ac88-bddc31892c4d","added_by":"auto","created_at":"2026-05-11 11:33:27","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":418470,"visible":true,"origin":"","legend":"\u003cp\u003eRadiographic measurement methods: Fused segment height (FSH) calculated as (AB+CD)/2; the angle β formed by the lower edge of C2 vertebra and the lower edge of C7 vertebra is considered as the C2–7 Cobb angle\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/5c46ccb708a4a629022d28b9.png"},{"id":108977935,"identity":"e4f79005-ee8d-444d-ab06-84d081d77765","added_by":"auto","created_at":"2026-05-11 11:33:28","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":69071,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of C2–7 Cobb angle among the three groups\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/dfc03775ea9abf6e0bafaf88.png"},{"id":108939305,"identity":"9edb9d7c-5dfe-45c3-a353-bf74089434e8","added_by":"auto","created_at":"2026-05-11 05:07:04","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":62813,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of fused segment height among the three groups\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/aed431572dfbce6148ed0fc7.png"},{"id":108977912,"identity":"52e0b8af-0787-4df8-b18e-f8cbcd30e31d","added_by":"auto","created_at":"2026-05-11 11:33:26","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":66868,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of subsidence among the three groups\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/6cac36713b50dcfb765221d0.png"},{"id":108939306,"identity":"14a3cf55-938e-4b52-95f1-c4d25d28eabf","added_by":"auto","created_at":"2026-05-11 05:07:04","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":38363,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in VAS scores among the three groups\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/6ebf53326db535065fe3b374.png"},{"id":108978307,"identity":"2d1f0679-d6ae-4b23-9556-3dc7868fc69c","added_by":"auto","created_at":"2026-05-11 11:36:06","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":57762,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in JOA scores among the three groups\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/da8fdec93558b36f94b9ed0c.png"},{"id":108939307,"identity":"60c3c192-76b8-47f7-8ee5-1800b2c6bd07","added_by":"auto","created_at":"2026-05-11 05:07:04","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":61751,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in NDI scores among the three groups\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/d1ea9e1d7c757bac03b8366e.png"},{"id":108978313,"identity":"a70adaf5-6d36-4d37-8d2a-f591e5d18383","added_by":"auto","created_at":"2026-05-11 11:36:10","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":544262,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative case of a 67-year-old male patient treated with single-level ACCF using a 3DP-AVB. (a) Preoperative lateral radiograph. (b) Preoperative sagittal CT image showing index-level compression. (c) Immediate postoperative lateral radiograph. (d) Lateral radiograph at final follow-up showing complete fusion. (e) Flexion lateral radiograph at final follow-up. (f) Extension lateral radiograph at final follow-up.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/7d2654b0789e99af3b7ca383.png"},{"id":108939310,"identity":"b0bc94a0-1712-4703-90b4-8236220a63ba","added_by":"auto","created_at":"2026-05-11 05:07:04","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":255762,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative case of a 52-year-old female patient treated with single-level ACCF using a 3DP-AVB. (a) Preoperative lateral radiograph. (b) Immediate postoperative lateral radiograph. (c) Final follow-up lateral radiograph showing maintenance of segmental height/alignment and fusion.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/b683831b5b9a7d1b69d31308.png"},{"id":108977727,"identity":"ea1080eb-20b5-49b5-b44e-19a44eb02c5c","added_by":"auto","created_at":"2026-05-11 11:32:42","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":296601,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative case of a 47-year-old male patient treated with single-level ACCF using a 3DP-AVB. (a) Preoperative lateral radiograph. (b) Immediate postoperative lateral radiograph. (c) Final follow-up lateral radiograph demonstrating postoperative alignment and implant stability.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/f6bae271307123180d0fd9e9.png"},{"id":108939312,"identity":"fda1f62e-65e9-4d36-9b55-e7d7ecb3352c","added_by":"auto","created_at":"2026-05-11 05:07:04","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":268695,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative case of a 54-year-old female patient treated with single-level ACCF using an n-HA/PA66 cage. (a) Preoperative lateral radiograph. (b) Immediate postoperative lateral radiograph. (c) Final follow-up lateral radiograph showing fusion status and sagittal alignment.\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/9d8617fa16886284945cb5e6.png"},{"id":108978041,"identity":"162d6856-865a-4362-8d7b-fe23f5e8ad9a","added_by":"auto","created_at":"2026-05-11 11:33:49","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":195246,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative case of a 72-year-old male patient treated with single-level ACCF using a TMC. (a) Preoperative lateral radiograph. (b) Immediate postoperative lateral radiograph. (c) Final follow-up lateral radiograph showing complete fusion.\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/6e7cf3692ee91c1592859441.png"},{"id":109081327,"identity":"0d36556d-b9a0-47b9-b0d4-44797d457067","added_by":"auto","created_at":"2026-05-12 12:16:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3283072,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9025630/v1/f10032aa-0734-4a57-a645-3894cc7957a1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Three-dimensional printed artificial vertebral body versus titanium mesh cage and nanohydroxyapatite/polyamide-66 cage in anterior cervical corpectomy and fusion: a retrospective cohort study with a minimum 5-year follow-up","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAnterior cervical corpectomy and fusion (ACCF) is an established surgical option for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL)[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. By directly removing ventral compressive lesions, it can provide effective decompression of the spinal cord and may result in satisfactory neurological recovery in appropriately selected patients[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Nevertheless, reconstruction after corpectomy remains challenging, particularly because graft-related complications and postoperative loss of sagittal alignment may still occur[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe reconstructive strategy used in anterior cervical surgery has gradually changed over time. Autologous iliac crest bone grafting was historically regarded as the standard method, but donor-site morbidity limited its wider acceptance[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Cage-based reconstruction was subsequently adopted to avoid graft harvest. Titanium mesh cages (TMCs) reduced donor-site complications, yet implant subsidence remained a persistent concern. Nanohydroxyapatite/polyamide-66 (n-HA/PA66) cages were later introduced because of their osteoconductive properties, although radiographic height loss and interface-related problems have not been completely eliminated[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAdvances in additive manufacturing have enabled the clinical use of three-dimensional printed artificial vertebral bodies (3DP-AVBs). Their porous architecture can be adjusted to better approximate the mechanical behavior of native bone while also facilitating osseointegration[\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. From a theoretical perspective, this design may reduce elastic modulus mismatch, improve load transfer, and support more stable implant-bone integration.\u003c/p\u003e \u003cp\u003eAlthough these implants are increasingly used in cervical reconstruction, direct comparisons among TMCs, n-HA/PA66 cages, and 3DP-AVBs remain limited. The present retrospective cohort study was therefore performed to compare the long-term radiographic and clinical outcomes of these three reconstructive options after single-level ACCF. We expected that 3DP-AVB would show better radiographic performance, particularly in terms of subsidence control and maintenance of cervical sagittal alignment.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study design, aim, and setting\u003c/h2\u003e \u003cp\u003eThis retrospective cohort study was conducted at the Departments of Spinal Surgery of China-Japan Friendship Hospital and Beijing Hospital of Traditional Chinese Medicine (Beijing, China), from September 2016 to September 2020. The study was approved by the institutional ethics committees of both hospitals. Written informed consent was waived because of the retrospective design, in accordance with national regulations and institutional requirements.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Participants\u003c/h2\u003e \u003cp\u003eConsecutive patients who underwent single-level anterior cervical corpectomy and fusion (ACCF) for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) during the study period were screened for inclusion. The inclusion criteria were: (1) age 18\u0026ndash;80 years; (2) diagnosis confirmed by magnetic resonance imaging (MRI) and computed tomography (CT); (3) complete clinical and radiographic data; and (4) a minimum follow-up of 60 months. The exclusion criteria were: multilevel corpectomy, previous cervical surgery, traumatic or infectious pathology, severe osteoporosis (T-score\u0026thinsp;\u0026lt;\u0026thinsp;\u0026minus;\u0026thinsp;2.5 on dual-energy X-ray absorptiometry), and systemic or psychiatric disorders that might affect outcome assessment.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Surgical procedure\u003c/h2\u003e \u003cp\u003eAll procedures were performed by a senior spine surgeon with more than 15 years of surgical experience. A standardized right-sided Smith-Robinson anterior cervical approach was used[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. After complete corpectomy, the endplates were prepared carefully with curettes to preserve the subchondral bony structure while removing the cartilaginous endplate. Implant size was selected intraoperatively to obtain an appropriate fit without excessive distraction. Autologous bone harvested from the resected vertebral body was morselized and tightly packed into the implant.\u003c/p\u003e \u003cp\u003e Patients in the 3DP-AVB group received a 3D-printed artificial vertebral body (Beijing AK Medical Co., Ltd., Beijing, China), with implant dimensions selected according to intraoperative measurements. The n-HA/PA66 group received nanohydroxyapatite/polyamide-66 cages (Sichuan National Nano Science and Technology Co., Ltd., Chengdu, China). The TMC group received titanium mesh cages (Fule Science \u0026amp; Technology Development Co., Ltd., Beijing, China), which were trimmed intraoperatively to improve endplate conformity (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). An anterior cervical plate was applied in all patients. After surgery, all patients wore a rigid cervical collar for 12 weeks.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Outcome assessment\u003c/h2\u003e \u003cp\u003eThe primary radiographic outcomes included fused segment height (FSH), implant subsidence, the C2-7 Cobb angle measured on standing lateral radiographs, and fusion status at 12 months (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Subsidence was defined as a decrease of 3 mm or more in FSH compared with the immediate postoperative measurement. Fusion was evaluated using the available postoperative imaging. Initial assessment was based on anteroposterior and lateral cervical radiographs. Fusion was considered present when continuous bridging bone crossed the operated segment and no radiolucent gap was identified between the grafted area and the adjacent vertebral endplates[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. When plain radiographs were inconclusive, CT with sagittal and coronal reconstruction was reviewed. Fusion was then confirmed when continuous bridging bone, particularly extragraft bridging bone, was seen across the operated segment without intervening lucency[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSecondary outcomes were clinical measures, including the Visual Analog Scale (VAS; 0\u0026ndash;10) for neck and arm pain, the Japanese Orthopaedic Association (JOA) score (0\u0026ndash;17) for myelopathy severity, and the Neck Disability Index (NDI; 0\u0026ndash;50) for functional impairment. Assessments were performed preoperatively and at 3 months and the final follow-up (\u0026ge;\u0026thinsp;60 months).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Radiographic assessment\u003c/h2\u003e \u003cp\u003eRadiographic measurements were independently performed by two spine surgeons, both blinded to the clinical outcomes. Interobserver reliability was evaluated using intraclass correlation coefficients, and all ICC values were greater than 0.85. Subsidence was quantified as the change in the vertical distance between the inferior endplate of the cranial vertebra and the superior endplate of the caudal vertebra at the operated level[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Statistical analysis\u003c/h2\u003e \u003cp\u003eAll statistical analyses were performed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). Continuous variables are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation and were compared using one-way analysis of variance (ANOVA) with Tukey's post hoc test, or the Kruskal-Wallis test when appropriate. Categorical variables are expressed as frequencies and were compared using the chi-square test or Fisher's exact test. All tests were two-sided, and P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. Because this was a retrospective study, no a priori sample size calculation was performed; the final sample size was determined by the number of eligible patients available during the study period.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Patient demographics\u003c/h2\u003e \u003cp\u003eA total of 101 patients met the inclusion criteria, including 34 in the TMC group, 34 in the n-HA/PA66 group, and 33 in the 3DP-AVB group. The baseline demographic and preoperative characteristics, including age, sex, BMI, bone mineral density (BMD), duration of follow-up and the operated level, were comparable among the three groups.\u003c/p\u003e \u003cp\u003eThe operative parameters also varied significantly across the groups. The 3DP-AVB group had the shortest operative time (97.70\u0026thinsp;\u0026plusmn;\u0026thinsp;11.29 min), followed by the TMC group (110.15\u0026thinsp;\u0026plusmn;\u0026thinsp;8.86 min) and the n-HA/PA66 group (118.41\u0026thinsp;\u0026plusmn;\u0026thinsp;11.20 min) (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Similarly, intraoperative blood loss was lowest in the 3DP-AVB group (86.61\u0026thinsp;\u0026plusmn;\u0026thinsp;8.43 mL), followed by the n-HA/PA66 group (91.62\u0026thinsp;\u0026plusmn;\u0026thinsp;10.17 mL) and the TMC group (96.71\u0026thinsp;\u0026plusmn;\u0026thinsp;11.67 mL) (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBaseline Demographic, Clinical, and Perioperative Characteristics of the Three Groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3DP-AVB (n\u0026thinsp;=\u0026thinsp;33)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003en-HA/PA66 (n\u0026thinsp;=\u0026thinsp;34)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTMC (n\u0026thinsp;=\u0026thinsp;34)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57.15\u0026thinsp;\u0026plusmn;\u0026thinsp;6.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e54.35\u0026thinsp;\u0026plusmn;\u0026thinsp;6.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55.32\u0026thinsp;\u0026plusmn;\u0026thinsp;7.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.257\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex (M/F)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20/13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17/17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18/16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.668\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.57\u0026thinsp;\u0026plusmn;\u0026thinsp;2.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24.66\u0026thinsp;\u0026plusmn;\u0026thinsp;2.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.56\u0026thinsp;\u0026plusmn;\u0026thinsp;2.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.080\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMD (T-score)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.50\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.44\u0026thinsp;\u0026plusmn;\u0026thinsp;0.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-0.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.303\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBlood loss (mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e86.61\u0026thinsp;\u0026plusmn;\u0026thinsp;8.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e91.62\u0026thinsp;\u0026plusmn;\u0026thinsp;10.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e96.71\u0026thinsp;\u0026plusmn;\u0026thinsp;11.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOperative time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e97.70\u0026thinsp;\u0026plusmn;\u0026thinsp;11.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e118.41\u0026thinsp;\u0026plusmn;\u0026thinsp;11.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e110.15\u0026thinsp;\u0026plusmn;\u0026thinsp;8.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow-up duration (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80.73\u0026thinsp;\u0026plusmn;\u0026thinsp;15.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e76.00\u0026thinsp;\u0026plusmn;\u0026thinsp;12.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73.18\u0026thinsp;\u0026plusmn;\u0026thinsp;15.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.106\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOperated level, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.467\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1(3.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2(5.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2(5.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8(24.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(8.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8(23.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14(42.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18(52.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18(52.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10(30.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11(32.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(17.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Radiographic outcomes\u003c/h2\u003e \u003cp\u003eThe 3DP-AVB group demonstrated superior radiographic outcomes compared with the n-HA/PA66 and TMC groups. Specifically, the 3DP-AVB group had the lowest subsidence rate (15.2% vs. 32.4% vs. 44.1%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and the smallest loss of fused segment height (1.99\u0026thinsp;\u0026plusmn;\u0026thinsp;0.73 mm vs. 2.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70 mm vs. 3.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.81 mm, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In addition, cervical sagittal alignment was better preserved in the 3DP-AVB group, which showed a significantly greater C2\u0026ndash;7 Cobb angle at final follow-up than the n-HA/PA66 and TMC groups (19.47\u0026thinsp;\u0026plusmn;\u0026thinsp;3.31\u0026deg; vs. 15.19\u0026thinsp;\u0026plusmn;\u0026thinsp;3.25\u0026deg; vs. 15.75\u0026thinsp;\u0026plusmn;\u0026thinsp;3.54\u0026deg;, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Fusion was achieved in all patients by 12 months, resulting in a 100% fusion rate in all three groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Clinical outcomes\u003c/h2\u003e \u003cp\u003eAll three groups showed significant postoperative improvement in JOA, NDI, and VAS scores. Baseline clinical scores were comparable among the groups, including preoperative JOA, NDI, and VAS scores (P\u0026thinsp;=\u0026thinsp;0.156, P\u0026thinsp;=\u0026thinsp;0.551, and P\u0026thinsp;=\u0026thinsp;0.093, respectively).\u003c/p\u003e \u003cp\u003eAt 3 months postoperatively, significant between-group differences were observed in JOA and NDI scores (P\u0026thinsp;=\u0026thinsp;0.022 and P\u0026thinsp;=\u0026thinsp;0.002, respectively), whereas VAS scores remained comparable across the groups (P\u0026thinsp;=\u0026thinsp;0.952). These between-group differences in JOA and NDI persisted at the final follow-up. The 3DP-AVB group showed the highest final JOA score (15.09\u0026thinsp;\u0026plusmn;\u0026thinsp;1.28), compared with the n-HA/PA66 group (13.59\u0026thinsp;\u0026plusmn;\u0026thinsp;1.37) and the TMC group (13.53\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44) (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The 3DP-AVB group also showed the lowest final NDI score (10.03\u0026thinsp;\u0026plusmn;\u0026thinsp;1.57), compared with the n-HA/PA66 group (11.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.45) and the TMC group (11.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.61) (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Final VAS scores remained comparable among groups (P\u0026thinsp;=\u0026thinsp;0.864) (Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Complications\u003c/h2\u003e \u003cp\u003eNo infections, cerebrospinal fluid leakage, or perioperative deaths were observed (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The most common complications were transient dysphagia and adjacent segment disease (ASD) requiring revision. Dysphagia occurred in 6.1%, 8.8%, and 14.7% of patients in the 3DP-AVB, n-HA/PA66, and TMC groups, respectively, with no significant between-group difference (P\u0026thinsp;=\u0026thinsp;0.480). Hoarseness or recurrent laryngeal nerve palsy was observed in 3.0%, 5.9%, and 11.8% of patients, respectively (P\u0026thinsp;=\u0026thinsp;0.356). ASD was numerically more frequent in the TMC group (8.8%) than in the 3DP-AVB group (3.0%) or the n-HA/PA66 group (2.9%), although the difference was not statistically significant (P\u0026thinsp;=\u0026thinsp;0.442).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePostoperative Complications During Follow-Up\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComplication\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3DP-AVB\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;33) n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003en-HA/PA66\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;34) n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTMC\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;34) n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInfection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDysphagia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (8.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (14.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.480\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHoarseness / recurrent laryngeal nerve palsy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (5.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (11.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.356\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCSF leakage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNew/worsened neurological deficit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdjacent Segment Disease (ASD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (8.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.442\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eIn the present cohort, reconstruction with 3DP-AVB was associated with more stable radiographic findings over long-term follow-up than reconstruction with either n-HA/PA66 cages or TMCs after single-level ACCF. The main differences were observed in subsidence, fused segment height loss, and maintenance of cervical sagittal alignment. At the same time, all three implants achieved fusion and were associated with postoperative clinical improvement. These findings suggest that the main advantage of 3DP-AVB lies in preservation of structural support over time rather than in uniform superiority across all measured outcomes.\u003c/p\u003e \u003cp\u003eEarlier comparative studies have also reported improved structural stability and radiographic maintenance with 3D-printed vertebral body devices in anterior cervical reconstruction[\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The present study adds longer-term follow-up to that body of evidence, showing that the radiographic differences remained evident after at least 5 years. In clinical terms, successful reconstruction depends not only on immediate postoperative stability, but also on preservation of segmental height and alignment throughout the later healing period.\u003c/p\u003e \u003cp\u003eSubsidence remains a major concern after ACCF because it may lead to loss of segmental height, local malalignment, and progressive reduction in construct stability during follow-up[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Previous biomechanical studies have shown that implant geometry, endplate matching, and stress distribution at the bone-implant interface play important roles in this process[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Clinical and radiographic studies have similarly linked these factors to height loss and late radiographic deterioration[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. From this perspective, the lower subsidence rate in the 3DP-AVB group is more likely to reflect implant-specific structural characteristics that improve load transfer and reduce stress concentration at the adjacent endplates.\u003c/p\u003e \u003cp\u003eThe comparison with n-HA/PA66 cages is also informative. Previous clinical studies have suggested that n-HA/PA66 cages may perform better than TMCs with respect to subsidence and radiographic maintenance[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], although loss of height and interface-related radiographic changes may still occur[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. A similar pattern was observed in the present study: the n-HA/PA66 group performed better than the TMC group in several radiographic measures, but remained inferior to the 3DP-AVB group. This gradient across the three implants indicates that the outcome of ACCF reconstruction depends not only on whether fusion is eventually achieved, but also on how well structural support is maintained while fusion is taking place.\u003c/p\u003e \u003cp\u003eComparative evidence in ACCF has increasingly pointed toward a radiographic advantage for 3DP-AVB. Wei et al. reported in a prospective randomized cohort that 3DP-AVBs were associated with less subsidence and better preservation of cervical lordosis than TMCs[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Fang et al. and He et al. also described advantages in fused segment height and alignment preservation[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. More recent comparative studies have shown similar trends in different cohorts[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In addition, mechanical studies have demonstrated that newer 3D-printed titanium cage designs may provide stronger resistance to subsidence than conventional titanium cages[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. These biomechanical observations offer a plausible explanation for the present radiographic findings.\u003c/p\u003e \u003cp\u003eOne practical advantage of 3D printing is the ability to control implant geometry, pore size, and overall porosity with greater precision[\u003cspan additionalcitationids=\"CR26 CR27\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Porous titanium constructs can therefore be designed to better balance mechanical strength and elastic modulus, which may reduce stiffness mismatch and improve load transfer at the bone-implant interface[\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Such structural optimization may account, at least in part, for the lower subsidence rate and better maintenance of sagittal alignment observed in the 3DP-AVB group. In this setting, durable reconstruction depends not only on fusion itself, but also on the mechanical interaction between the implant and the adjacent endplates.\u003c/p\u003e \u003cp\u003eLong-term implant behavior is influenced not only by mechanical support, but also by biological fixation. Although n-HA/PA66 constructs can achieve high fusion rates, previous studies have described interface-related radiographic findings, including radiolucent gaps, suggesting that osseointegration may not always be optimal[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. In contrast, the interconnected porous structure of 3DP-AVB may provide a more favorable scaffold for bone ingrowth and implant-bone integration[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. This difference in biological behavior may have contributed to the more durable radiographic performance observed in the present cohort.\u003c/p\u003e \u003cp\u003eAll three groups demonstrated substantial postoperative clinical improvement, indicating that adequate decompression and reconstruction were achieved regardless of implant type. However, recovery was not identical across all clinical measures. Differences among groups were observed for JOA and NDI at 3 months and remained evident at final follow-up, whereas VAS scores were comparable. This pattern suggests that the potential clinical benefit associated with 3DP-AVB may be more apparent in neurological recovery and functional improvement than in pain relief alone.\u003c/p\u003e \u003cp\u003eThe lack of consistent differences across all clinical outcomes should be interpreted cautiously. Recovery after ACCF is influenced by multiple factors, including preoperative neurological status, adequacy of decompression, postoperative rehabilitation, and other patient-related variables in addition to implant characteristics[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. As a result, implant selection may have a more direct influence on radiographic durability than on symptom relief itself. Even so, preservation of cervical sagittal alignment may still be clinically relevant, because postoperative sagittal parameters have been associated with functional outcomes after anterior cervical surgery[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe complication profile was acceptable in all three groups, and no infection, cerebrospinal fluid leakage, or perioperative death was observed. The most frequent complications were transient dysphagia, hoarseness or recurrent laryngeal nerve-related symptoms, and adjacent segment disease requiring revision. Although these events were numerically more common in the TMC group, the between-group differences were not statistically significant. This finding is consistent with earlier reports indicating that complications after anterior cervical corpectomy remain clinically relevant and may be influenced by both construct stability and the technical demands of reconstruction[\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Given the modest sample size, any possible relationship between improved endplate matching and a lower complication rate should be interpreted with caution.\u003c/p\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Limitations\u003c/h2\u003e \u003cp\u003eThis study has several limitations. First, because of its retrospective design, selection bias and residual confounding cannot be completely excluded, and implant selection may have been influenced by surgeon preference, implant availability, or changes in practice over time. Second, the sample size was relatively small, which may have reduced statistical power, particularly for complication-related comparisons and more fully adjusted analyses. Third, only single-level ACCF cases were included; therefore, extrapolation of the present findings to multilevel procedures, revision surgery, severe osteoporosis, or other complex reconstructive settings should be cautious. Finally, although the minimum 5-year follow-up strengthens the longitudinal value of the study, longer observation is still needed to clarify implant durability, adjacent segment degeneration, and the clinical relevance of better radiographic preservation over time. Larger prospective multicentre studies are needed to confirm these observations and further define the indications for 3DP-AVB reconstruction.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Clinical implications\u003c/h2\u003e \u003cp\u003eThe present findings are relevant to implant selection in ACCF reconstruction. When several reconstructive options are available, 3DP-AVB may be considered for patients who are thought to be at greater risk of subsidence or postoperative loss of alignment, particularly when endplate support and load distribution are major concerns. More broadly, these results indicate that implant selection after ACCF should not be judged by fusion status alone, but also by how well structural stability is preserved during follow-up. From this perspective, 3DP-AVB may be particularly useful when long-term radiographic maintenance is a major surgical priority. Prospective multicentre studies are still required to further clarify its indications[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eIn this retrospective cohort with a minimum follow-up of 5 years, 3DP-AVB reconstruction was associated with less subsidence and better maintenance of cervical alignment than n-HA/PA66 or TMC reconstruction after single-level ACCF. All three reconstructive methods achieved fusion and were followed by postoperative clinical improvement. Compared with the radiographic findings, the clinical differences were less consistent: JOA and NDI favored 3DP-AVB, whereas VAS scores were similar among groups. Overall, these findings indicate that 3DP-AVB may offer better long-term radiographic durability after single-level ACCF, with possible advantages in neurological and functional recovery. Further prospective multicentre studies are required for confirmation.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eACCF: anterior cervical corpectomy and fusion\u003c/p\u003e\n\u003cp\u003e3DP-AVB: three-dimensional printed artificial vertebral body\u003c/p\u003e\n\u003cp\u003en-HA/PA66: nanohydroxyapatite/polyamide-66\u003c/p\u003e\n\u003cp\u003eTMC: titanium mesh cage\u003c/p\u003e\n\u003cp\u003eASD: adjacent segment disease\u003c/p\u003e\n\u003cp\u003eBMD: bone mineral density\u003c/p\u003e\n\u003cp\u003eBMI: body mass index\u003c/p\u003e\n\u003cp\u003eCSF: cerebrospinal fluid\u003c/p\u003e\n\u003cp\u003eCSM: cervical spondylotic myelopathy\u003c/p\u003e\n\u003cp\u003eCT: computed tomography\u003c/p\u003e\n\u003cp\u003eFSH: fused segment height\u003c/p\u003e\n\u003cp\u003eICC: intraclass correlation coefficient\u003c/p\u003e\n\u003cp\u003eJOA: Japanese Orthopaedic Association\u003c/p\u003e\n\u003cp\u003eMRI: magnetic resonance imaging\u003c/p\u003e\n\u003cp\u003eNDI: Neck Disability Index\u003c/p\u003e\n\u003cp\u003eOPLL: ossification of the posterior longitudinal ligament\u003c/p\u003e\n\u003cp\u003eSD: standard deviation\u003c/p\u003e\n\u003cp\u003eVAS: Visual Analog Scale\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEthical Approval\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committees of both China-Japan Friendship Hospital and Beijing Hospital of Traditional Chinese Medicine. The requirement for written informed consent was waived due to the retrospective nature of the study, in accordance with national ethical regulations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eFunding\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Beijing Capital Health Development Research Special Project (Grant No. 2024-2-2233).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCompeting Interests\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAvailability of Data and Materials\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZhang AS, Myers C, McDonald CL, Alsoof D, Anderson G, Daniels AH. Cervical Myelopathy: Diagnosis, Contemporary Treatment, and Outcomes. Am J Med. 2022;135(4):435\u0026ndash;43. Epub 2021 Nov 30. PMID: 34861202.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGhogawala Z. Anterior Cervical Option to Manage Degenerative Cervical Myelopathy. Neurosurg Clin N Am. 2018;29(1):83\u0026ndash;89. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.nec.2017.09.005\u003c/span\u003e\u003cspan address=\"10.1016/j.nec.2017.09.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 29173439.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang D, Du X, Liang H, Hu W, Hu H, Cheng X. Anterior corpectomy versus posterior laminoplasty for the treatment of multilevel cervical myelopathy: A meta-analysis. Int J Surg. 2016;35:21\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ijsu.2016.09.008\u003c/span\u003e\u003cspan address=\"10.1016/j.ijsu.2016.09.008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2016 Sep 10. PMID: 27622728.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang S, Xiang Y, Wang X, Li H, Hou Y, Zhao H, Pan X. Anterior corpectomy comparing to posterior decompression surgery for the treatment of multi-level ossification of posterior longitudinal ligament: A meta-analysis. Int J Surg. 2017;40:91\u0026ndash;6. Epub 2017 Feb 22. PMID: 28254423.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSawin PD, Traynelis VC, Menezes AH. A comparative analysis of fusion rates and donor-site morbidity for autogeneic rib and iliac crest bone grafts in posterior cervical fusions. J Neurosurg. 1998;88(2):255\u0026thinsp;\u0026ndash;\u0026thinsp;65. doi: 10.3171/jns.1998.88.2.0255. PMID: 9452233.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhong W, Liang X, Tang K, Luo X, Quan Z, Jiang D. Nanohydroxyapatite/polyamide 66 strut subsidence after one-level corpectomy: underlying mechanism and effect on cervical neurological function. Sci Rep. 2018;8(1):12098. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/s41598-018-30678-1\u003c/span\u003e\u003cspan address=\"10.1038/s41598-018-30678-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 30108277; PMCID: PMC6092369.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWei F, Xu N, Li Z, Cai H, Zhou F, Yang J, Yu M, Liu X, Sun Y, Zhang K, Pan S, Wu F, Liu Z. A prospective randomized cohort study on 3D-printed artificial vertebral body in single-level anterior cervical corpectomy for cervical spondylotic myelopathy. Ann Transl Med. 2020;8(17):1070. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.21037/atm-19-4719\u003c/span\u003e\u003cspan address=\"10.21037/atm-19-4719\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 33145289; PMCID: PMC7575998.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFang T, Zhang M, Yan J, Zhao J, Pan W, Wang X, Zhou Q. Comparative Analysis of 3D-Printed Artificial Vertebral Body Versus Titanium Mesh Cage in Repairing Bone Defects Following Single-Level Anterior Cervical Corpectomy and Fusion. Med Sci Monit. 2021;27:e928022. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.12659/MSM.928022\u003c/span\u003e\u003cspan address=\"10.12659/MSM.928022\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 33550326; PMCID: PMC7876950.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe H, Fan L, L\u0026uuml; G, Li X, Li Y, Zhang O, Chen Z, Yuan H, Pan C, Wang X, Kuang L. Myth or fact: 3D-printed off-the-shelf prosthesis is superior to titanium mesh cage in anterior cervical corpectomy and fusion? BMC Musculoskelet Disord. 2024;25(1):96. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12891-024-07213-7\u003c/span\u003e\u003cspan address=\"10.1186/s12891-024-07213-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 38279132; PMCID: PMC10811816.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSMITH GW, ROBINSON RA. The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. J Bone Joint Surg Am. 1958;40\u0026ndash;A(3):607\u0026ndash;24. PMID: 13539086.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee J, Lee DH, Jung CW, Song KS. The Significance of Extra-Cage Bridging Bone via Radiographic Lumbar Interbody Fusion Criterion. Global Spine J. 2023;13(1):113\u0026ndash;21. doi: 10.1177/2192568221993097. Epub 2021 Feb 18. PMID: 33596702; PMCID: PMC9837518.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSong KS, Chaiwat P, Kim HJ, Mesfin A, Park SM, Riew KD. Anterior cervical fusion assessment using reconstructed computed tomographic scans: surgical confirmation of 254 segments. Spine (Phila Pa 1976). 2013;38(25):2171-7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/BRS.0000000000000017\u003c/span\u003e\u003cspan address=\"10.1097/BRS.0000000000000017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 24048090.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTang Y, Geng X, Li F, Sun Y, Jia L, Zhou S, Chen X. Factors affecting titanium mesh cage subsidence in single-level anterior cervical corpectomy and fusion for ossification of the posterior longitudinal ligament. J Orthop Surg Res. 2022;17(1):515. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13018-022-03409-6\u003c/span\u003e\u003cspan address=\"10.1186/s13018-022-03409-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 36457100; PMCID: PMC9714211.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang H, Qu R, Xia T, Geng H, Yi Z, Sun Y, Zhang F, Pan S, Chen X, Zhao Y, Liu Z, Zhou F. Artificial vertebral body versus titanium mesh cage for single-level anterior cervical corpectomy and fusion (ACCF): a propensity score matching analysis of fusion, implant subsidence and clinical outcomes. BMC Musculoskelet Disord. 2025;26(1):1060. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12891-025-09308-1\u003c/span\u003e\u003cspan address=\"10.1186/s12891-025-09308-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 41257777; PMCID: PMC12628911.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J, Zhang J, Wang B, Huang K, Yang X, Song Y, Liu H, Rong X. Spine (Phila Pa 1976). 2025;50(2):88\u0026ndash;95. Epub 2024 Aug 23. PMID: 39175433. Comparison of Titanium Mesh Cage, Nano-Hydroxyapatite/Polyamide Cage, and Three-Dimensional-Printed Vertebral Body for Anterior Cervical Corpectomy and Fusion.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRuomu Q, Haoxiang W, Tian X, Hanbo G, Yanbin Z, Yinze D, Xin C, Shengfa P, Li Z, Shaobo W, Fengshan Z, Yu S, Zhong Jun L, Feifei Z. Risk factors of early subsidence of 3D-printed artificial vertebral body following single-level anterior cervical corpectomy and fusion (ACCF): retrospective study of 98 patients. J Orthop Surg Res. 2025;20(1):633. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13018-025-06056-9\u003c/span\u003e\u003cspan address=\"10.1186/s13018-025-06056-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 40635074; PMCID: PMC12243176.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHee HT, Majd ME, Holt RT, Whitecloud TS 3rd, Pienkowski D. Complications of multilevel cervical corpectomies and reconstruction with titanium cages and anterior plating. J Spinal Disord Tech. 2003;16(1):1\u0026ndash;8; discussion 8\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00024720-200302000-00001\u003c/span\u003e\u003cspan address=\"10.1097/00024720-200302000-00001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 12571477.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHirai T, Yoshii T, Sakai K, Inose H, Yuasa M, Yamada T, Matsukura Y, Ushio S, Morishita S, Egawa S, Onuma H, Kobayashi Y, Utagawa K, Hashimoto J, Kawabata A, Tanaka T, Motoyoshi T, Takahashi T, Hashimoto M, Sakaeda K, Kato T, Arai Y, Kawabata S, Okawa A. Anterior Cervical Corpectomy with Fusion versus Anterior Hybrid Fusion Surgery for Patients with Severe Ossification of the Posterior Longitudinal Ligament Involving Three or More Levels: A Retrospective Comparative Study. J Clin Med. 2021;10(22):5315. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/jcm10225315\u003c/span\u003e\u003cspan address=\"10.3390/jcm10225315\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 34830602; PMCID: PMC8624558.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhou E, Huang H, Zhao Y, Wang L, Fan Y. The effects of titanium mesh cage size on the biomechanical responses of cervical spine after anterior cervical corpectomy and fusion: A finite element study. Clin Biomech (Bristol). 2022;91:105547. Epub 2021 Dec 13. PMID: 34923190.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang KR, Yang Y, Ma LT, Qiu Y, Wang BY, Ding C, Meng Y, Rong X, Hong Y, Liu H. Biomechanical Effects of a Novel Anatomic Titanium Mesh Cage for Single-Level Anterior Cervical Corpectomy and Fusion: A Finite Element Analysis. Front Bioeng Biotechnol. 2022;10:881979. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fbioe.2022.881979\u003c/span\u003e\u003cspan address=\"10.3389/fbioe.2022.881979\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 35814021; PMCID: PMC9263189.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu B, Wang L, Song Y, Hu Y, Lyu Q, Liu L, Zhu C, Zhou C, Yang X. A comparison of long-term outcomes of nanohydroxyapatite/polyamide-66 cage and titanium mesh cage in anterior cervical corpectomy and fusion: A clinical follow-up study of least 8 years. Clin Neurol Neurosurg. 2019;176:25\u0026ndash;9. Epub 2018 Nov 19. PMID: 30481654.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhong W, Liang X, Luo X, Quan Z, Jiang D. Imaging evaluation of nano-hydroxyapatite/polyamide 66 strut in cervical construction after 1-level corpectomy: a retrospective study of 520 patients. Eur J Med Res. 2020;25(1):38. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s40001-020-00440-3\u003c/span\u003e\u003cspan address=\"10.1186/s40001-020-00440-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 32873339; PMCID: PMC7466497.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang H, Wang Y, Miao J, Wang J, Li H, Zhang Y, Yan L, Wang B. Analysis of the anti-subsidence mechanical properties of novel 3D-printed titanium cages compared to conventional titanium cages. J Orthop Surg Res. 2025;20(1):854. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13018-025-06237-6\u003c/span\u003e\u003cspan address=\"10.1186/s13018-025-06237-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 41013548; PMCID: PMC12465666.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKiselev R, Zheravin A. Clinical Application of 3D-Printed Artificial Vertebral Body (3DP AVB): A Review. J Pers Med. 2024;14(10):1024. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/jpm14101024\u003c/span\u003e\u003cspan address=\"10.3390/jpm14101024\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 39452532; PMCID: PMC11508315.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi L, Shi J, Zhang K, Yang L, Yu F, Zhu L, Liang H, Wang X, Jiang Q. Early osteointegration evaluation of porous Ti6Al4V scaffolds designed based on triply periodic minimal surface models. J Orthop Translat. 2019;19:94\u0026ndash;105. PMID: 31844617; PMCID: PMC6896722.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eParthasarathy J, Starly B, Raman S, Christensen A. Mechanical evaluation of porous titanium (Ti6Al4V) structures with electron beam melting (EBM). J Mech Behav Biomed Mater. 2010;3(3):249\u0026ndash;59. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jmbbm.2009.10.006\u003c/span\u003e\u003cspan address=\"10.1016/j.jmbbm.2009.10.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2009 Oct 22. PMID: 20142109.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaniguchi N, Fujibayashi S, Takemoto M, Sasaki K, Otsuki B, Nakamura T, Matsushita T, Kokubo T, Matsuda S. Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: An in vivo experiment. Mater Sci Eng C Mater Biol Appl. 2016;59:690\u0026ndash;701. Epub 2015 Oct 28. PMID: 26652423.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi JX, Peng HT, Chen ZY, Hu CB, He T, Li H, Quan ZX. Insight Into Osseointegration of Nanohydroxyapatite/Polyamide 66 Based on the Radiolucent Gap: Comparison With Polyether-Ether-Ketone. Front Mater. 2021;8:678550. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fmats.2021.678550\u003c/span\u003e\u003cspan address=\"10.3389/fmats.2021.678550\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y, Deng X, Jiang D, Luo X, Tang K, Zhao Z, Zhong W, Lei T, Quan Z. Long-term results of anterior cervical corpectomy and fusion with nano-hydroxyapatite/polyamide 66 strut for cervical spondylotic myelopathy. Sci Rep. 2016;6:26751. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/srep26751\u003c/span\u003e\u003cspan address=\"10.1038/srep26751\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 27225189; PMCID: PMC4880938.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpece H, Basgul C, Andrews CE, MacDonald DW, Taheri ML, Kurtz SM. A systematic review of preclinical in vivo testing of 3D printed porous Ti6Al4V for orthopedic applications, part I: Animal models and bone ingrowth outcome measures. J Biomed Mater Res B Appl Biomater. 2021;109(10):1436\u0026ndash;54. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/jbm.b.34803\u003c/span\u003e\u003cspan address=\"10.1002/jbm.b.34803\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2021 Jan 22. PMID: 33484102.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLewallen EA, Riester SM, Bonin CA, Kremers HM, Dudakovic A, Kakar S, Cohen RC, Westendorf JJ, Lewallen DG, van Wijnen AJ. Biological strategies for improved osseointegration and osteoinduction of porous metal orthopedic implants. Tissue Eng Part B Rev. 2015;21(2):218\u0026ndash;30. Epub 2014 Dec 18. PMID: 25348836; PMCID: PMC4390115.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y, Quan Z, Zhao Z, Luo X, Tang K, Li J, Zhou X, Jiang D. Evaluation of anterior cervical reconstruction with titanium mesh cages versus nano-hydroxyapatite/polyamide66 cages after 1- or 2-level corpectomy for multilevel cervical spondylotic myelopathy: a retrospective study of 117 patients. PLoS ONE. 2014;9(5):e96265. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1371/journal.pone.0096265\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0096265\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 24789144; PMCID: PMC4008500.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang X, Huang D, Han J, Luo J, Wang Y. Mid-Term Functional Recovery After ACDF and ACCF in the Treatment of Adjacent Two-Level Cervical Spondylosis: A Comparative Study. J Pain Res. 2025;18:3009\u0026ndash;16. PMID: 40546827; PMCID: PMC12182085.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFan XW, Wang ZW, Gao XD, Ding WY, Yang DL. The change of cervical sagittal parameters plays an important role in clinical outcomes of cervical spondylotic myelopathy after multi-level anterior cervical discectomy and fusion. J Orthop Surg Res. 2019;14(1):429. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13018-019-1504-3\u003c/span\u003e\u003cspan address=\"10.1186/s13018-019-1504-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 31829200; PMCID: PMC6907178.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang T, Li J, Li X, Pan X, Gao X, Yang X, Ma X, Li H, Feng S, Liu Z. An innovative self-stabilised 3D-printed artificial vertebral body designed for clinical application and comparison with the conventional implants. J Orthop Translat. 2025;53:52\u0026ndash;62. PMID: 40529899; PMCID: PMC12173030.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeng M, Wang J, Sun T, Zhang W, Zhang J, Shu L, Li Z. Clinical applications and prospects of 3D printing guide templates in orthopaedics. J Orthop Translat. 2022;34:22\u0026ndash;41. PMID: 35615638; PMCID: PMC9117878.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJing Z, Zhang T, Xiu P, Cai H, Wei Q, Fan D, Lin X, Song C, Liu Z. Functionalization of 3D-printed titanium alloy orthopedic implants: a literature review. Biomed Mater. 2020;15(5):052003. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1088/1748-605X/ab9078\u003c/span\u003e\u003cspan address=\"10.1088/1748-605X/ab9078\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 32369792.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang X, Guo Q, He Y, Geng X, Wang C, Li Y, Li Z, Wang C, Qiu D, Tian H. A pH-neutral bioactive glass coated 3D-printed porous Ti6Al4V scaffold with enhanced osseointegration. J Mater Chem B. 2023;11(6):1203\u0026ndash;1212. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1039/d2tb02129c\u003c/span\u003e\u003cspan address=\"10.1039/d2tb02129c\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 36515141.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang H, Wu Z, Wang Z, Yan X, Duan X, Sun H. Advanced surface modification techniques for titanium implants: a review of osteogenic and antibacterial strategies. Front Bioeng Biotechnol. 2025;13:1549439. doi: 10.3389/fbioe.2025.1549439. Erratum in: Front Bioeng Biotechnol. 2025;13:1629360. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fbioe.2025.1629360\u003c/span\u003e\u003cspan address=\"10.3389/fbioe.2025.1629360\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 40177619; PMCID: PMC11962728.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLlopis-Grimalt MA, Arb\u0026oacute;s A, Gil-Mir M, Mosur A, Kulkarni P, Salito A, Ramis JM, Monjo M. Multifunctional Properties of Quercitrin-Coated Porous Ti-6Al-4V Implants for Orthopaedic Applications Assessed In Vitro. J Clin Med. 2020;9(3):855. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/jcm9030855\u003c/span\u003e\u003cspan address=\"10.3390/jcm9030855\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 32245053; PMCID: PMC7141521.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMok SW, Nizak R, Fu SC, Ho KK, Qin L, Saris DBF, Chan KM, Malda J. From the printer: Potential of three-dimensional printing for orthopaedic applications. J Orthop Translat. 2016;6:42\u0026ndash;9. PMID: 30035082; PMCID: PMC5987023.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"anterior cervical corpectomy and fusion, 3D-printed artificial vertebral body, titanium mesh cage, nanohydroxyapatite/polyamide-66 cage, subsidence, cervical sagittal alignment","lastPublishedDoi":"10.21203/rs.3.rs-9025630/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9025630/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground: Anterior cervical corpectomy and fusion (ACCF) is a commonly performed procedure for cervical spondylotic myelopathy (CSM), but the choice of reconstructive device after corpectomy remains unsettled. Titanium mesh cages (TMCs) and nanohydroxyapatite/polyamide-66 (n-HA/PA66) cages are both widely used in clinical practice, although subsidence and postoperative loss of cervical alignment remain important concerns. Three-dimensional printed artificial vertebral bodies (3DP-AVBs) have been introduced as an alternative reconstructive option. This study assessed the long-term radiographic and clinical outcomes of 3DP-AVB, n-HA/PA66, and TMC reconstruction after single-level ACCF.\u003c/p\u003e\n\u003cp\u003eMethods: This retrospective cohort study included 101 patients with CSM who underwent single-level ACCF at two centres. Reconstruction was performed using a 3DP-AVB (n = 33), an n-HA/PA66 cage (n = 34), or a TMC (n = 34). Clinical and radiographic data were reviewed with a minimum follow-up of 5 years. Radiographic outcomes included fusion status, subsidence, fused segment height (FSH), and cervical sagittal alignment. Clinical outcomes included the Visual Analog Scale (VAS), Japanese Orthopaedic Association (JOA) score, and Neck Disability Index (NDI). Complications and revision procedures were also recorded.\u003c/p\u003e\n\u003cp\u003eResults: At final follow-up, the 3DP-AVB group had a lower subsidence rate than the n-HA/PA66 and TMC groups (15.2% vs. 32.4% vs. 44.1%; P \u0026lt; 0.001), less loss of FSH (1.99 ± 0.73 vs. 2.80 ± 0.70 vs. 3.07 ± 0.81 mm; P \u0026lt; 0.001), and better preservation of cervical sagittal alignment (C2-7 Cobb angle, 19.47 ± 3.31° vs. 15.19 ± 3.25° vs. 15.75 ± 3.54°; P \u0026lt; 0.001). Fusion was achieved in all patients by 12 months. All three groups improved after surgery. Differences in JOA and NDI were observed at 3 months and remained significant at final follow-up (final JOA, 15.09 ± 1.28 vs. 13.59 ± 1.37 vs. 13.53 ± 1.44; final NDI, 10.03 ± 1.57 vs. 11.88 ± 1.45 vs. 11.88 ± 1.61; both P \u0026lt; 0.001). VAS scores were similar among groups.\u003c/p\u003e\n\u003cp\u003eConclusions: In patients undergoing single-level ACCF, 3DP-AVB reconstruction was associated with lower subsidence and better maintenance of cervical alignment during long-term follow-up than n-HA/PA66 or TMC reconstruction. All three reconstructive methods achieved fusion and postoperative clinical improvement. Compared with the other two implants, 3DP-AVB may provide greater radiographic durability and may also be associated with better neurological and functional recovery. Further prospective multicentre studies are needed.\u003c/p\u003e\n\u003cp\u003eTrial registration: Not applicable (retrospective cohort).\u003c/p\u003e","manuscriptTitle":"Three-dimensional printed artificial vertebral body versus titanium mesh cage and nanohydroxyapatite/polyamide-66 cage in anterior cervical corpectomy and fusion: a retrospective cohort study with a minimum 5-year follow-up","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-11 05:06:59","doi":"10.21203/rs.3.rs-9025630/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-17T08:54:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"78978266261678774649903351216701789131","date":"2026-05-04T12:04:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"155171159046547483324693369201899350496","date":"2026-05-04T11:31:41+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-27T10:27:47+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-07T12:02:25+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-07T12:01:27+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Orthopaedic Surgery and Research","date":"2026-03-04T04:12:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e1904885-229e-4719-889f-af91c63e64fb","owner":[],"postedDate":"May 11th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-17T08:54:47+00:00","index":32,"fulltext":""},{"type":"reviewerAgreed","content":"78978266261678774649903351216701789131","date":"2026-05-04T12:04:03+00:00","index":31,"fulltext":""},{"type":"reviewerAgreed","content":"155171159046547483324693369201899350496","date":"2026-05-04T11:31:41+00:00","index":30,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T05:06:59+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-11 05:06:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9025630","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9025630","identity":"rs-9025630","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}