Regression of anterior cervical disc-osteophyte complex following artificial disc replacement – A radiological phenomenon

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Regression of anterior cervical disc osteophyte complex after CDA is a less commonly recognized and understood radiological finding, one which was previously only described following fusion. Our aim is to describe the regression of anterior cervical disc osteophyte complex following CDA, and discuss its potential clinical significance. Methods Baseline characteristics, clinical presentation, perioperative details, and postoperative details were collected of patients who underwent CDA with a minimum of 2-year follow up. Presence of implant subsidence, peri-implant fractures, and heterotopic ossification were also recorded. Radiological parameters including pre and postoperative global cervical alignment, segmental range of motion, protrusion of cervical disc-osteophyte complex at each vertebral level. Results 50 patients (122 levels) were analyzed. Regression of anterior cervical disc osteophytes was observed in 92 levels (75%) at 3-month postoperatively, 75 levels (61%) at 1-year postoperatively, and 40 levels (33%) at 2-year postoperatively. Mean osteophyte size significantly decreased from immediate postoperative period up to 1-year follow-up ( p < 0.005), with no significant difference in osteophyte size between 1 and 2-year follow-up. Range of motion of C2-7 and operated functional spinal unit improved throughout all 3 follow-up timepoints. Heterotopic ossification was observed up to 35 levels (28%) at 2-year follow-up. Conclusion Regression of anterior cervical disc-osteophyte complex following CDA suggests stress distribution and restoration of movement in the cervical spine, and may be a useful predictor of satisfactory functional and radiological outcomes. Cervical disc arthroplasty motion preservation regression of disc-osteophyte complex cervical spondylosis heterotopic ossification Figures Figure 1 Figure 2 Figure 3 Introduction Anterior compressive pathologies of the cervical spine are associated with significant burden of disease worldwide, with associated symptoms of radiculopathy and/or myelopathy resulting in worsened function and quality of life[ 1 ]. Traditionally, anterior cervical discectomy and fusion (ACDF) is the gold standard treatment for symptomatic anterior cervical disease – with proven reliability in achieving adequate decompression, spinal stability and satisfactory patient outcomes[ 2 , 3 ]. However, the process of eliminating segmental motion causes increased spinal stiffness which in turn stresses adjacent disc segments[ 4 ]. Pseudoarthrosis may occur at the operated levels[ 5 ], and accelerated degeneration in the adjacent segments, both possibly leading to the need for revision spinal surgery – with more pronounced effects following an increase in number of levels operated [ 6 – 8 ]. Over the past decade, cervical disc arthroplasty (CDA) has gained popularity as an efficacious and suitable alternative to ACDF for treatment of anterior cervical compressive pathologies, with reported equivalent or superior short-to-medium-term clinical and radiological outcomes compared to fusion [ 9 – 13 ]. CDA has been shown to confer several advantages over ACDF in terms of motion preservation [ 4 ], lower rates of symptomatic adjacent segment degeneration [ 10 ], and lower rates of revision surgeries at both operated and adjacent levels [ 10 , 12 ]. Moreover, CDA has the added advantage of protecting the same level from pseudoarthrosis revision – a complication of fusion with higher rates than CDA prosthesis catastrophic failures [ 14 – 16 ]. However, a less commonly recognized and understood radiological finding is the regression of anterior cervical disc-osteophyte complex after CDA – a phenomenon of osteophytic resorption in the cervical spine previously only described following anterior or posterior cervical instrumentation and fusion [ 17 , 18 ]. Although regression of anterior cervical disc osteophyte complexes following fusion has been attributed to motion restriction and subsequent lack of strain at the instrumented levels [ 17 ], the authors believe that a similar phenomenon following CDA occurs due to healthy stress redistribution, a result of rebalancing the spine with desirable controlled mobility, with clinical implications. To the authors’ best knowledge, regression of anterior cervical disc osteophyte complex following CDA has not been described in the literature. The objective of the present study is to describe the regression of anterior cervical disc osteophyte complex following CDA, and discuss its potential clinical significance. Materials and Methods Study design and patient selection This is a retrospective review of hospital data. Patients who underwent CDA surgery with the Prodisc-C Vivo implant (Centinel Spine, West Chester, PA) performed by a fellowship-trained spine surgeon with 10 years of operative experience at a single tertiary institution between March 2022 and April 2023 were retrospectively enrolled into the study following local ethics board approval. Indications for CDA included patients with clinically and radiologically concordant diagnosis of cervical spondylotic radiculopathy who have failed at least 6 weeks of conservative treatment as well as those with myelopathy. All included patients needed to have preoperative cervical spinal imaging (X-ray or slot scanned images) showing ≥ 3mm of anterior disc-osteophyte complex in anteroposterior plane. All patients had computed-tomography (CT) scan of the cervical spine preoperatively, as well as anteroposterior/ lateral/ flexion/extension X-rays of the cervical spine preoperatively, immediate postoperatively, and at time points up to 2 years of follow-up. Patients with prior cervical spinal surgery, severe facet arthritis, tumor, infection, or vertebral fractures were excluded. Surgical technique All surgeries were performed by the senior author using his described techniques[ 4 , 19 ]. Patients were positioned supine with the cervical spine maximally extended and strapped at the chin and shoulders. Left sided transverse skin crease approach is used. When above 3 levels were performed at a single setting, 2 incisions were used. After blunt dissection to the prevertebral space, a subperiosteal plane was developed on the anterior vertebra body surface and Caspar pins were placed. Anterior longitudinal ligaments were incised at the discs to gain access to the intervertebral space. A sharp ultracut was used to tear the side annulus completely by gliding laterally along the uncus until a “give” was felt. Intervertebral distraction up to a minimum distance of at least 8mm was achieved for every level during the discectomy and preparation of the endplates. Each endplate was raised enbloc using the ultacut followed by clearance of remaining residues using an angled curette. Under direct visualization of a headlight, kerrison punches were used for complete resection of posterior longitudinal ligament. When decompression of nerve root is required, posterior third of the uncus on the affected side is excised. Retrovertebral decompression when desired is performed using trumpet osteotomy cuts for surgical corridors. Prosthesis was inserted under the strict guidance of intra-operative fluoroscopy until the desired position is achieved. This is done in distraction and following finalisation of prosthesis position, compression is allowed via Caspar pins. The wound is closed at the platysma muscle and skin layers following single drain insertion. This drain is removed on the first postoperative day. Postoperatively, no cervical orthosis is worn. All patients go through immediate forced flexion exercises – 20 repetitions three times a day - upon reversal of general anaesthesia [ 19 ]. Data collection We collected baseline patient demographics (age, sex, body mass index, smoking history, comorbidities), clinical presentation and diagnosis, perioperative details (level of surgery performed, duration of surgery, blood loss, intraoperative complications), and postoperative details (length of hospitalization, return to work/usual activities of daily living, postoperative complications). Radiographic parameters measured included pre- and postoperative global cervical alignment (GCA) and segmental range of motion (SROM). Protrusion of anterior cervical disc-osteophyte complex at each vertebral level (either over the cranial or caudal endplates) was measured using digital calipers – whereby a digital straight line continuous and in-line with the endplate was subtended from the anterior vertebral body line of the index vertebra. The measurement recorded by digital caliper between the anterior vertebral body line and a perpendicular line subtended to the point of maximal disc-osteophyte complex protrusion was recorded as the size of the disc-osteophyte complex at the endplate (Fig. 1 ). Additionally, the presence of implant subsidence (reduction of more than 2mm in vertebral height at the anterior, mid or posterior vertebral body line), peri-implant fractures, and heterotopic ossification (using McAfee’s classification from Grade I-IV) were also radiographically evaluated at latest follow-up. All radiographic measurements were performed by two independent spine surgeons not directly involved in management of study patients, using the institution’s picture archiving and communications system (PACS). Statistical Analysis All statistical analysis was conducted using IBM SPSS Statistics v25.0 (IBM Corp., Armonk, NY, USA), with statistical significance set at p < .05 throughout. Categorical variables were analyzed using Fisher’s exact test. Continuous variables were summarized using mean and standard deviations and analyzed using Mann–Whitney U test and Wilcoxon rank-sum tests. Comparisons of normally distributed continuous variables were made using an independent T-test. Results Baseline characteristics A total of 50 patients comprising 122 cervical levels with a minimum follow up period of 2 years were included in the study (Table 1 ). Eight patients underwent a single level CADR, with 42 patients undergoing multilevel CADR (16 two-level, 20 three-level, and 6 four-level). There were 26 males (52%), and a relatively equal distribution of patients with cervical myelopathy and radiculopathy. Table 1 Baseline Patient Characteristics and Peri-operative data Number of patients ( n ) 50 Number of cervical levels ( n ) C3/4 C4/5 C5/6 C6/7 122 19 29 42 32 Mean age (years) 59.22 (± 11.9) Mean BMI 24.9 (± 3.0) Surgical Duration (mins/level) 53.4 Mean Blood Loss (mLs/level) 8.4 Intraoperative/postoperative blood transfusions ( n ) 0 Length of Hospital Stay (days) 1.1 (± 1.1) Readmissions ( n ) 0 Postoperative complications ( n ) 1 (2%) Radiological outcomes At 3-month postoperative follow up, a total of 92 operated levels were noted to have regression of anterior cervical disc osteophytes, with significant reduction in osteophyte size compared to immediate postoperative period ( p < 0.005) (Table 2 ). At the 1-year postoperative period, a total of 75 operated levels had regression of anterior cervical disc osteophytes, of which 66 levels had further regression from the 3-month follow up period. Osteophyte size reduction at this timepoint was also significant compared to the 3-month postoperative period ( p < 0.005). At the 2-year postoperative period, 40 operated levels had regression of anterior cervical disc osteophytes, with 32 levels further regressing from the 1-year follow up period. Of note, osteophyte size at 2-year follow up was not statistically significantly different from the 1-year follow up timepoint ( p = 0.313). Preoperative mean segmental range of motion was 9.6° (± 6.0), and 4.6° (± 4.7) at immediate postoperative period, 7.5° (± 5.5) at 3 months postoperatively, 8.2° (± 5.4) at 1 year postoperatively, and 8.3° (± 5.5) at 2 years postoperatively. Preoperative C2-C7 range of motion was 35.5° (± 20.8), and 17.1° (± 9.8) at immediate postoperative period, 35.3° (± 12.8) at 3 months postoperatively, 34.2° (± 13.0) at 1 year postoperatively, and 37° (± 11.5) at 2 years postoperatively. No peri-implant fractures were observed in the patients included. Only one case of implant subsidence was noted at 2-year follow up. Heterotopic ossification was observed in 14 levels at 3-month follow up, 27 levels at 1-year follow up, and 35 levels at 2-year follow up. Table 2 Radiological outcomes Preoperative Immediate postoperative 3-month postoperative 1-year postoperative 2-years postoperative Regression of anterior cervical disc osteophytes ( n of levels) N/A N/A 92 75 (66 levels with continued regression, 9 levels new regression) 40 (32 levels with continued regression, 8 levels new regression) Mean osteophyte size (mm) N/A 2.89 (SD 1.86) 1.98 (SD 1.56) 1.37 (SD 1.51) 1.45 (SD 1.62) Statistical significance Immediate postoperative N/A N/A p < 0.005 p < 0.005 p < 0.005 3-month postoperative N/A N/A N/A p < 0.005 p < 0.005 1-year postoperative N/A N/A N/A N/A p = 0.313 FSU angular range of motion (°) 9.58 (SD 5.99) 4.57 (SD 4.70) 7.46 (SD 5.54) 8.15 (SD 5.39) 8.28 SD (5.45) C2-C7 range of motion (°) 35.54 (SD 20.79) 17.13 (SD 9.75) 35.25 (SD 12.77) 34.18 (SD 12.97) 36.99 (SD 11.48) Heterotopic Ossification ( n of levels) Grade 1 - - 13 11 11 Grade 2 - - 0 7 4 Grade 3 - - 1 9 12 Grade 4 - - 0 0 8 Implant subsidence ( n of levels) - - 0 0 1 Peri-implant fractures ( n of levels) - - 0 0 0 Discussion CDA has emerged as an effective motion-preserving surgical alternative to ACDF for the management of symptomatic cervical degenerative disc disease refractory to conservative treatment [ 20 ]. When performed in prime indications, CDA has been shown to provide comparable and possibly superior clinical outcomes, and has been associated with lower long-term healthcare costs [ 21 ]. Unlike ACDF, which ends with a rigid fixation and segmental immobilization, CDA offers several biomechanical advantages, including preservation of healthy ROM, no pseudoarthrosis, a decreased incidence of ASD, and a significant reduction in secondary surgeries at both the index and adjacent levels [ 4 , 16 , 22 , 23 ]. Comparative analyses have demonstrated that single-level CDA achieves superior outcomes relative to ACDF with respect to overall clinical success, neurological improvement, pain relief, complication rates, patient-reported satisfaction, and preservation of adjacent segment integrity [ 24 ]. These findings are corroborated by Level I prospective randomized controlled trials, which further highlight the superiority of two-level CDA over two-level ACDF in terms of both clinical and functional endpoints in selected cases at follow-up durations of up to 84 months [ 25 , 26 ]. CDA is increasingly being performed in expanded indications such as elderly patients with substantial spinal degenerative changes. Following discectomy, from a biomechanical perspective, ACDF eliminates motion at the index level through fusion, thereby increasing mechanical stress on adjacent segments. This shift in load distribution at the adjacent spinal segments elevates intradiscal pressure (IDP) and facet joint forces (FJF), accelerating ASD [ 27 , 28 ]. Finite element modeling and postoperative imaging have confirmed that ACDF results in increased ROM, annular stress, and dehydration at adjacent discs, particularly during flexion-extension movements [ 29 ]. In contrast, CDA maintains segmental mobility and facilitates more physiological load distribution along the cervical spine. The use of an artificial disc reduces facet joint overload and contributes to a more favorable biomechanical environment. CDA has been shown to preserve preoperative ROM while reducing IDP and FJF at neighboring levels, factors believed to mitigate the development of ASD over time[ 30 ]. In our series, radiographic evaluation revealed spontaneous regression of anterior osteophytes following CDA. This finding supports a biomechanical hypothesis: rather than stress elimination as typically observed in fusion procedures, it is the healthy redistribution of mechanical stress in the cervical spine through allowing mobility following CDA that may facilitate osteophyte resorption. Osteophyte regression following ACDF or laminectomy with fusion has been attributed to mechanical unloading, a mechanism consistent with Wolff’s law and the Heuter-Volkmann principle [ 17 ]. According to these principles, bone continuously remodels in response to mechanical stimuli. Under dynamic loading, bone maintains or reinforces its structural integrity, whereas in the absence of stress, osteoclastic resorption may predominate [ 31 ]. Fusion procedures reduce mechanical loading of key spinal structures such as Sharpey’s fibers, intervertebral discs, and dentate ligaments, which may account for the gradual regression of hypertrophic bone observed over time. Data from other clinical scenarios also corroborate this mechanism, particularly in 1) cervical laminoplasty where partial loss of motion—often attributed to laminar auto-fusion on the hinged side—has been associated with progressive resorption of disc-osteophyte complexes during follow-up, and 2) posterior instrumented fusion of the cervical spine also has an effect of reducing growth rates of ossification of posterior longitudinal ligament [ 32 ]. In contrast, CDA engages a biomechanically distinct yet mechanically consistent pathway—one that remains congruent with Wolff’s law, albeit through stress redistribution rather than stress elimination. We postulate that unlike fusion-based approaches that promote remodeling via unloading, CDA may induce a comparable biological response through evenly distributed stress loading and restoration of healthy mobility, a state perceived by the body as being natural. Such modulation of stress may serve as a potent stimulus for osteoclastic activity at the osteophyte–ligament–bone interface, thereby facilitating spontaneous resorption of hypertrophic bone which becomes unnecessary after CDA. The interesting findings of this study yield several clinical implications. In patients with good balanced-releases and segmental remobilization, coupled with appropriately selected and positioned prosthesis to achieve good segmental and global cervical ROM, favorable bone remodeling—such as anterior osteophyte regression—may occur spontaneously via physiological redistribution of mechanical stress. This underscores the importance of surgical technique in CDR, which will undeniably be more demanding than ACDF. Naturally, achieving a single preferred implant alignment in fusion will never be as challenging as obtaining healthy post-operative mobility following prosthesis placement. Nevertheless, it is important to highlight that our study only examines this radiological phenomenon up to 2 years, which unless healthy mobility is continued longer, regrowth of anterior osteophytes may still occur. This emphasizes the importance of encouraging early and sustained postoperative mobilization to ensure longevity of the results. The presence of HO in a minority of our patients may be due to multifactorial causes (Fig. 3 ), of which, inevitable aggressive resection of osteophytes may be a leading reasons and can be further investigated in another study. Spontaneous regression of anterior disc-osteophyte complexes may serve as a valuable postoperative radiographic marker, indicative not only of procedural success but also of restored healthy segmental spinal mechanics. The presence of this finding is both interesting and encouraging. It supports our current understanding that there can be some reversibility of disease pathologies should treatment be delivered early and appropriately. In this case, having anterior osteophyte formation is not irreversible. Moreover, it also demonstrates the possibility of rejuvenation of the mobile spine using CDA in terms of not simply treating the patients’ symptoms, but also being able to restore the proper mechanics of the degenerated spine. With these results, guidelines should look again at the contraindications of CDA and focus on the need for proper surgical techniques to be able expand the indications of CDA for greater benefit to our patients. This study has some limitations. First, its retrospective nature, single-center design, as well as the limited sample size will inherently have some effect on the reliability of the reported results. However, radiological findings will not be influenced by these issues and remain objective proof of our findings. Second, the regression of disc osteophytes was analyzed using radiographic 2D imaging rather than utilizing a volumetric 3D assessment (i.e., using CT). Therefore, osteophyte size evaluation might have been affected by the patient position during X-ray acquisition as well as by the subjective nature of imaging assessment. This we believe will have little impact especially when regression is qualitatively obvious and is trended over time. Third, we caution that the results may not be applicable to every center as the technique of CDR will differ from surgeon-to-surgeon and prosthesis-to-prosthesis. Variation in surgical techniques and prosthesis use has been shown to affect outcomes. Last, while promising in terms of radiological evaluation, the real clinical relevance of osteophyte regression in the setting of CDA still needs to be further demonstrated with larger and longer prospective clinical studies looking at patient reported outcome scores. Conclusion Regression of anterior cervical disc-osteophyte complex following CDA is common with proper surgical technique and prosthesis. This phenomenon highlights the strengths of CDA in stress distribution and restoration of movement in the cervical spine. Its presence can be regarded as a positive feedback interpreted by the body, and may become a useful predictor of satisfactory functional and radiological outcomes. Declarations Competing Interests : the authors declare that they have no competing interests. Ethics approval : this study was approved by the local institutional ethics board. As this was a retrospective review of anonymized data, the requirement for informed consent was waived. Funding: the authors received no financial support for the research, authorship, and/or publication of this article. Author Contribution E.d.R. and Z.C. conceived the study and drafted the initial manuscript; E.L.K. and A.Q.A.T. contributed to data collection and analysis; T.J.H. and S.L. performed radiological measurements and statistical analysis; D.H.H.W. supervised the project, provided critical revisions, and ensured overall scientific integrity. All authors reviewed and approved the final version of the manuscript. Acknowledgements: The first two co-authors contributed equally to this work. 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Int J Artif Organs 47:411–417. https://doi.org/10.1177/03913988241259969 Sheng XQ, Wu TK, Liu H, Meng Y (2023) Incidence of heterotopic ossification at 10 years after cervical disk replacement: a systematic review and meta-analysis. Spine (Phila Pa 1976) 48:E203–E215. https://doi.org/10.1097/BRS.0000000000004674 Wang W, Zheng X, Wang H, Zuo B, Chen S, Li J (2024) Mechanical unloading promotes osteoclastic differentiation and bone resorption by modulating the MSC secretome to favor inflammation. Cell Transpl 33:9636897241236584. https://doi.org/10.1177/09636897241236584 Lee JJ, Shin DA, Yi S, Kim KN, Yoon DH, Shin HC, Ha Y (2018) Effect of posterior instrumented fusion on three-dimensional volumetric growth of cervical ossification of the posterior longitudinal ligament: a multiple regression analysis. Spine J 18:1779–1786 Additional Declarations No competing interests reported. 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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-8704317","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":592421108,"identity":"dff897b6-ca47-4f17-aa23-4a4252a6301b","order_by":0,"name":"Brian Zhaojie Chin","email":"","orcid":"","institution":"National University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Brian","middleName":"Zhaojie","lastName":"Chin","suffix":""},{"id":592421109,"identity":"0a08aed5-5e20-4350-83d4-8f133f3765c7","order_by":1,"name":"Elisabetta de Rinaldis","email":"","orcid":"","institution":"Università Campus Bio-Medico","correspondingAuthor":false,"prefix":"","firstName":"Elisabetta","middleName":"","lastName":"de Rinaldis","suffix":""},{"id":592421110,"identity":"07a90ad4-d0d7-469d-b429-0706cccecd80","order_by":2,"name":"Evelyn Linyi Koh","email":"","orcid":"","institution":"National University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Evelyn","middleName":"Linyi","lastName":"Koh","suffix":""},{"id":592421111,"identity":"87cf1213-04d6-471d-ae9d-ca52f16f824c","order_by":3,"name":"Alex Quok An Teo","email":"","orcid":"","institution":"National University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Alex","middleName":"Quok An","lastName":"Teo","suffix":""},{"id":592421112,"identity":"3d3c3151-76b5-4c5a-b77d-a7972c4e4a6d","order_by":4,"name":"Junhao Tan","email":"","orcid":"","institution":"National University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Junhao","middleName":"","lastName":"Tan","suffix":""},{"id":592421113,"identity":"8ea75549-478f-47ca-a275-6aa9902eea72","order_by":5,"name":"Shuxun Lin","email":"","orcid":"","institution":"Ng Teng Fong General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shuxun","middleName":"","lastName":"Lin","suffix":""},{"id":592421114,"identity":"089f5ddf-42f9-4e0c-8ad5-561f809aa839","order_by":6,"name":"Hwee Weng Dennis Hey","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIiWNgGAWjYDCCAwxsDAxsNhAODwla0kjXcpgELXzH25895ik7n2dw/gDjg7dtDPbyDgS0SJ45Y27Mc+52scGNBGbDuW0MiRsPENBicCOHTTq37XbihhsMbNK8bQwJhg0EtaQ/A2o5l7jh/AH230At9kRoSTADajmQuOFAAhszUAvjfAI6QH4xk/5zLjlx5o3EZsk55yQSNxDSAgoxyRlldol95w8f/PCmzMZenpDDkAAjSK0Eg8EB4rVAASm2jIJRMApGwcgAAEcPQ6V3WUEXAAAAAElFTkSuQmCC","orcid":"","institution":"National University of Singapore","correspondingAuthor":true,"prefix":"","firstName":"Hwee","middleName":"Weng Dennis","lastName":"Hey","suffix":""}],"badges":[],"createdAt":"2026-01-26 23:53:36","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8704317/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8704317/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103166089,"identity":"02324285-e683-4d03-925b-eea76b3d0736","added_by":"auto","created_at":"2026-02-22 12:37:13","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":43409,"visible":true,"origin":"","legend":"\u003cp\u003eMethod of measuring syndesmophyte length at caudal endplate of C4. AVBL, anterior vertebral body line (line a-b); SL, syndesmophyte length (line b-c)\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8704317/v1/b132735d258c65e405556ad2.jpeg"},{"id":103505052,"identity":"63371eba-1936-4475-b7fc-6411863a9d0d","added_by":"auto","created_at":"2026-02-26 13:22:41","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":246792,"visible":true,"origin":"","legend":"\u003cp\u003eRegression of Anterior Cervical Disc Osteophytes after Artificial Disc Replacement\u003cem\u003e \u003c/em\u003e(from preoperative to 2-year postoperative follow up)\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8704317/v1/b42e8299516baaa4616209cf.jpeg"},{"id":103166091,"identity":"0ebe771d-9d9d-4100-81e2-d1d9d918379a","added_by":"auto","created_at":"2026-02-22 12:37:14","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":79737,"visible":true,"origin":"","legend":"\u003cp\u003eHeterotopic Ossification after Artificial Disc Replacement\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8704317/v1/167aeab0e72475970d9e6b20.jpeg"},{"id":109289528,"identity":"0b5d49a4-d0bd-4b86-8f7a-cc00dcd02133","added_by":"auto","created_at":"2026-05-15 06:28:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":607450,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8704317/v1/e121fe48-b770-4825-9b8f-d51ccc96956b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Regression of anterior cervical disc-osteophyte complex following artificial disc replacement – A radiological phenomenon","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAnterior compressive pathologies of the cervical spine are associated with significant burden of disease worldwide, with associated symptoms of radiculopathy and/or myelopathy resulting in worsened function and quality of life[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Traditionally, anterior cervical discectomy and fusion (ACDF) is the gold standard treatment for symptomatic anterior cervical disease \u0026ndash; with proven reliability in achieving adequate decompression, spinal stability and satisfactory patient outcomes[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, the process of eliminating segmental motion causes increased spinal stiffness which in turn stresses adjacent disc segments[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Pseudoarthrosis may occur at the operated levels[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], and accelerated degeneration in the adjacent segments, both possibly leading to the need for revision spinal surgery \u0026ndash; with more pronounced effects following an increase in number of levels operated [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOver the past decade, cervical disc arthroplasty (CDA) has gained popularity as an efficacious and suitable alternative to ACDF for treatment of anterior cervical compressive pathologies, with reported equivalent or superior short-to-medium-term clinical and radiological outcomes compared to fusion [\u003cspan additionalcitationids=\"CR10 CR11 CR12\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. CDA has been shown to confer several advantages over ACDF in terms of motion preservation [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], lower rates of symptomatic adjacent segment degeneration [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], and lower rates of revision surgeries at both operated and adjacent levels [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Moreover, CDA has the added advantage of protecting the same level from pseudoarthrosis revision \u0026ndash; a complication of fusion with higher rates than CDA prosthesis catastrophic failures [\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. However, a less commonly recognized and understood radiological finding is the regression of anterior cervical disc-osteophyte complex after CDA \u0026ndash; a phenomenon of osteophytic resorption in the cervical spine previously only described following anterior or posterior cervical instrumentation and fusion [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Although regression of anterior cervical disc osteophyte complexes following fusion has been attributed to motion restriction and subsequent lack of strain at the instrumented levels [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], the authors believe that a similar phenomenon following CDA occurs due to healthy stress redistribution, a result of rebalancing the spine with desirable controlled mobility, with clinical implications. To the authors\u0026rsquo; best knowledge, regression of anterior cervical disc osteophyte complex following CDA has not been described in the literature. The objective of the present study is to describe the regression of anterior cervical disc osteophyte complex following CDA, and discuss its potential clinical significance.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and patient selection\u003c/h2\u003e \u003cp\u003e This is a retrospective review of hospital data. Patients who underwent CDA surgery with the Prodisc-C Vivo implant (Centinel Spine, West Chester, PA) performed by a fellowship-trained spine surgeon with 10 years of operative experience at a single tertiary institution between March 2022 and April 2023 were retrospectively enrolled into the study following local ethics board approval. Indications for CDA included patients with clinically and radiologically concordant diagnosis of cervical spondylotic radiculopathy who have failed at least 6 weeks of conservative treatment as well as those with myelopathy. All included patients needed to have preoperative cervical spinal imaging (X-ray or slot scanned images) showing\u0026thinsp;\u0026ge;\u0026thinsp;3mm of anterior disc-osteophyte complex in anteroposterior plane. All patients had computed-tomography (CT) scan of the cervical spine preoperatively, as well as anteroposterior/ lateral/ flexion/extension X-rays of the cervical spine preoperatively, immediate postoperatively, and at time points up to 2 years of follow-up. Patients with prior cervical spinal surgery, severe facet arthritis, tumor, infection, or vertebral fractures were excluded.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgical technique\u003c/h3\u003e\n\u003cp\u003eAll surgeries were performed by the senior author using his described techniques[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Patients were positioned supine with the cervical spine maximally extended and strapped at the chin and shoulders. Left sided transverse skin crease approach is used. When above 3 levels were performed at a single setting, 2 incisions were used. After blunt dissection to the prevertebral space, a subperiosteal plane was developed on the anterior vertebra body surface and Caspar pins were placed. Anterior longitudinal ligaments were incised at the discs to gain access to the intervertebral space. A sharp ultracut was used to tear the side annulus completely by gliding laterally along the uncus until a \u0026ldquo;give\u0026rdquo; was felt. Intervertebral distraction up to a minimum distance of at least 8mm was achieved for every level during the discectomy and preparation of the endplates. Each endplate was raised enbloc using the ultacut followed by clearance of remaining residues using an angled curette. Under direct visualization of a headlight, kerrison punches were used for complete resection of posterior longitudinal ligament. When decompression of nerve root is required, posterior third of the uncus on the affected side is excised. Retrovertebral decompression when desired is performed using trumpet osteotomy cuts for surgical corridors. Prosthesis was inserted under the strict guidance of intra-operative fluoroscopy until the desired position is achieved. This is done in distraction and following finalisation of prosthesis position, compression is allowed via Caspar pins. The wound is closed at the platysma muscle and skin layers following single drain insertion. This drain is removed on the first postoperative day. Postoperatively, no cervical orthosis is worn. All patients go through immediate forced flexion exercises \u0026ndash; 20 repetitions three times a day - upon reversal of general anaesthesia [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eData collection\u003c/h3\u003e\n\u003cp\u003eWe collected baseline patient demographics (age, sex, body mass index, smoking history, comorbidities), clinical presentation and diagnosis, perioperative details (level of surgery performed, duration of surgery, blood loss, intraoperative complications), and postoperative details (length of hospitalization, return to work/usual activities of daily living, postoperative complications).\u003c/p\u003e \u003cp\u003eRadiographic parameters measured included pre- and postoperative global cervical alignment (GCA) and segmental range of motion (SROM). Protrusion of anterior cervical disc-osteophyte complex at each vertebral level (either over the cranial or caudal endplates) was measured using digital calipers \u0026ndash; whereby a digital straight line continuous and in-line with the endplate was subtended from the anterior vertebral body line of the index vertebra. The measurement recorded by digital caliper between the anterior vertebral body line and a perpendicular line subtended to the point of maximal disc-osteophyte complex protrusion was recorded as the size of the disc-osteophyte complex at the endplate (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Additionally, the presence of implant subsidence (reduction of more than 2mm in vertebral height at the anterior, mid or posterior vertebral body line), peri-implant fractures, and heterotopic ossification (using McAfee\u0026rsquo;s classification from Grade I-IV) were also radiographically evaluated at latest follow-up. All radiographic measurements were performed by two independent spine surgeons not directly involved in management of study patients, using the institution\u0026rsquo;s picture archiving and communications system (PACS).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eAll statistical analysis was conducted using IBM SPSS Statistics v25.0 (IBM Corp., Armonk, NY, USA), with statistical significance set at \u003cem\u003ep\u003c/em\u003e \u0026lt;\u0026thinsp;.05 throughout. Categorical variables were analyzed using Fisher\u0026rsquo;s exact test. Continuous variables were summarized using mean and standard deviations and analyzed using Mann\u0026ndash;Whitney \u003cem\u003eU\u003c/em\u003e test and Wilcoxon rank-sum tests. Comparisons of normally distributed continuous variables were made using an independent T-test.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBaseline characteristics\u003c/h2\u003e \u003cp\u003eA total of 50 patients comprising 122 cervical levels with a minimum follow up period of 2 years were included in the study (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Eight patients underwent a single level CADR, with 42 patients undergoing multilevel CADR (16 two-level, 20 three-level, and 6 four-level). There were 26 males (52%), and a relatively equal distribution of patients with cervical myelopathy and radiculopathy.\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 Patient Characteristics and Peri-operative data\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of patients (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of cervical levels (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e \u003cp\u003eC3/4\u003c/p\u003e \u003cp\u003e C4/5\u003c/p\u003e \u003cp\u003e C5/6\u003c/p\u003e \u003cp\u003e C6/7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e122 \u003c/p\u003e \u003cp\u003e19\u003c/p\u003e \u003cp\u003e29\u003c/p\u003e \u003cp\u003e42\u003c/p\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean age (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e59.22 (\u0026plusmn;\u0026thinsp;11.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean BMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.9 (\u0026plusmn;\u0026thinsp;3.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurgical Duration (mins/level)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean Blood Loss (mLs/level)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntraoperative/postoperative blood transfusions (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of Hospital Stay (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.1 (\u0026plusmn;\u0026thinsp;1.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReadmissions (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative complications (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2%)\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\n\u003ch3\u003eRadiological outcomes\u003c/h3\u003e\n\u003cp\u003eAt 3-month postoperative follow up, a total of 92 operated levels were noted to have regression of anterior cervical disc osteophytes, with significant reduction in osteophyte size compared to immediate postoperative period (\u003cem\u003ep\u0026thinsp;\u0026lt;\u003c/em\u003e\u0026thinsp;0.005) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). At the 1-year postoperative period, a total of 75 operated levels had regression of anterior cervical disc osteophytes, of which 66 levels had further regression from the 3-month follow up period. Osteophyte size reduction at this timepoint was also significant compared to the 3-month postoperative period (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005). At the 2-year postoperative period, 40 operated levels had regression of anterior cervical disc osteophytes, with 32 levels further regressing from the 1-year follow up period. Of note, osteophyte size at 2-year follow up was not statistically significantly different from the 1-year follow up timepoint (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.313). Preoperative mean segmental range of motion was 9.6\u0026deg; (\u0026plusmn;\u0026thinsp;6.0), and 4.6\u0026deg; (\u0026plusmn;\u0026thinsp;4.7) at immediate postoperative period, 7.5\u0026deg; (\u0026plusmn;\u0026thinsp;5.5) at 3 months postoperatively, 8.2\u0026deg; (\u0026plusmn;\u0026thinsp;5.4) at 1 year postoperatively, and 8.3\u0026deg; (\u0026plusmn;\u0026thinsp;5.5) at 2 years postoperatively. Preoperative C2-C7 range of motion was 35.5\u0026deg; (\u0026plusmn;\u0026thinsp;20.8), and 17.1\u0026deg; (\u0026plusmn;\u0026thinsp;9.8) at immediate postoperative period, 35.3\u0026deg; (\u0026plusmn;\u0026thinsp;12.8) at 3 months postoperatively, 34.2\u0026deg; (\u0026plusmn;\u0026thinsp;13.0) at 1 year postoperatively, and 37\u0026deg; (\u0026plusmn;\u0026thinsp;11.5) at 2 years postoperatively. No peri-implant fractures were observed in the patients included. Only one case of implant subsidence was noted at 2-year follow up. Heterotopic ossification was observed in 14 levels at 3-month follow up, 27 levels at 1-year follow up, and 35 levels at 2-year follow up.\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\u003eRadiological outcomes\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImmediate postoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3-month postoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1-year postoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2-years \u003c/p\u003e \u003cp\u003epostoperative\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRegression of anterior cervical disc osteophytes \u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e of levels)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75 \u003c/p\u003e \u003cp\u003e(66 levels with continued regression, 9 levels new regression)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40 \u003c/p\u003e \u003cp\u003e(32 levels with continued regression, 8 levels new regression)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean osteophyte size (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.89 \u003c/p\u003e \u003cp\u003e(SD 1.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.98 \u003c/p\u003e \u003cp\u003e(SD 1.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.37 \u003c/p\u003e \u003cp\u003e(SD 1.51)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.45 \u003c/p\u003e \u003cp\u003e(SD 1.62)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eStatistical significance\u003c/em\u003e\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=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eImmediate postoperative\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e3-month postoperative\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e1-year postoperative\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ep\u0026thinsp;=\u003c/em\u003e\u0026thinsp;0.313\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFSU angular range of motion (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.58 \u003c/p\u003e \u003cp\u003e(SD 5.99)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.57 \u003c/p\u003e \u003cp\u003e(SD 4.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.46 \u003c/p\u003e \u003cp\u003e(SD 5.54)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.15 \u003c/p\u003e \u003cp\u003e(SD 5.39)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.28 \u003c/p\u003e \u003cp\u003eSD (5.45)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC2-C7 range of motion (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35.54 \u003c/p\u003e \u003cp\u003e(SD 20.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.13 \u003c/p\u003e \u003cp\u003e(SD 9.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35.25 \u003c/p\u003e \u003cp\u003e(SD 12.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34.18 \u003c/p\u003e \u003cp\u003e(SD 12.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e36.99 \u003c/p\u003e \u003cp\u003e(SD 11.48)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003eHeterotopic Ossification (\u003cem\u003en\u003c/em\u003e of levels)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eGrade 1\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eGrade 2\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eGrade 3\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eGrade 4\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImplant subsidence \u003c/p\u003e \u003cp\u003e (\u003cem\u003en\u003c/em\u003e of levels)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePeri-implant fractures (\u003cem\u003en\u003c/em\u003e of levels)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eCDA has emerged as an effective motion-preserving surgical alternative to ACDF for the management of symptomatic cervical degenerative disc disease refractory to conservative treatment [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. When performed in prime indications, CDA has been shown to provide comparable and possibly superior clinical outcomes, and has been associated with lower long-term healthcare costs [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Unlike ACDF, which ends with a rigid fixation and segmental immobilization, CDA offers several biomechanical advantages, including preservation of healthy ROM, no pseudoarthrosis, a decreased incidence of ASD, and a significant reduction in secondary surgeries at both the index and adjacent levels [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Comparative analyses have demonstrated that single-level CDA achieves superior outcomes relative to ACDF with respect to overall clinical success, neurological improvement, pain relief, complication rates, patient-reported satisfaction, and preservation of adjacent segment integrity [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. These findings are corroborated by Level I prospective randomized controlled trials, which further highlight the superiority of two-level CDA over two-level ACDF in terms of both clinical and functional endpoints in selected cases at follow-up durations of up to 84 months [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCDA is increasingly being performed in expanded indications such as elderly patients with substantial spinal degenerative changes. Following discectomy, from a biomechanical perspective, ACDF eliminates motion at the index level through fusion, thereby increasing mechanical stress on adjacent segments. This shift in load distribution at the adjacent spinal segments elevates intradiscal pressure (IDP) and facet joint forces (FJF), accelerating ASD [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Finite element modeling and postoperative imaging have confirmed that ACDF results in increased ROM, annular stress, and dehydration at adjacent discs, particularly during flexion-extension movements [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. In contrast, CDA maintains segmental mobility and facilitates more physiological load distribution along the cervical spine. The use of an artificial disc reduces facet joint overload and contributes to a more favorable biomechanical environment. CDA has been shown to preserve preoperative ROM while reducing IDP and FJF at neighboring levels, factors believed to mitigate the development of ASD over time[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our series, radiographic evaluation revealed spontaneous regression of anterior osteophytes following CDA. This finding supports a biomechanical hypothesis: rather than stress elimination as typically observed in fusion procedures, it is the healthy redistribution of mechanical stress in the cervical spine through allowing mobility following CDA that may facilitate osteophyte resorption. Osteophyte regression following ACDF or laminectomy with fusion has been attributed to mechanical unloading, a mechanism consistent with Wolff\u0026rsquo;s law and the Heuter-Volkmann principle [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. According to these principles, bone continuously remodels in response to mechanical stimuli. Under dynamic loading, bone maintains or reinforces its structural integrity, whereas in the absence of stress, osteoclastic resorption may predominate [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Fusion procedures reduce mechanical loading of key spinal structures such as Sharpey\u0026rsquo;s fibers, intervertebral discs, and dentate ligaments, which may account for the gradual regression of hypertrophic bone observed over time. Data from other clinical scenarios also corroborate this mechanism, particularly in 1) cervical laminoplasty where partial loss of motion\u0026mdash;often attributed to laminar auto-fusion on the hinged side\u0026mdash;has been associated with progressive resorption of disc-osteophyte complexes during follow-up, and 2) posterior instrumented fusion of the cervical spine also has an effect of reducing growth rates of ossification of posterior longitudinal ligament [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. In contrast, CDA engages a biomechanically distinct yet mechanically consistent pathway\u0026mdash;one that remains congruent with Wolff\u0026rsquo;s law, albeit through stress redistribution rather than stress elimination. We postulate that unlike fusion-based approaches that promote remodeling via unloading, CDA may induce a comparable biological response through evenly distributed stress loading and restoration of healthy mobility, a state perceived by the body as being natural. Such modulation of stress may serve as a potent stimulus for osteoclastic activity at the osteophyte\u0026ndash;ligament\u0026ndash;bone interface, thereby facilitating spontaneous resorption of hypertrophic bone which becomes unnecessary after CDA.\u003c/p\u003e \u003cp\u003eThe interesting findings of this study yield several clinical implications. In patients with good balanced-releases and segmental remobilization, coupled with appropriately selected and positioned prosthesis to achieve good segmental and global cervical ROM, favorable bone remodeling\u0026mdash;such as anterior osteophyte regression\u0026mdash;may occur spontaneously via physiological redistribution of mechanical stress. This underscores the importance of surgical technique in CDR, which will undeniably be more demanding than ACDF. Naturally, achieving a single preferred implant alignment in fusion will never be as challenging as obtaining healthy post-operative mobility following prosthesis placement. Nevertheless, it is important to highlight that our study only examines this radiological phenomenon up to 2 years, which unless healthy mobility is continued longer, regrowth of anterior osteophytes may still occur. This emphasizes the importance of encouraging early and sustained postoperative mobilization to ensure longevity of the results. The presence of HO in a minority of our patients may be due to multifactorial causes (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), of which, inevitable aggressive resection of osteophytes may be a leading reasons and can be further investigated in another study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSpontaneous regression of anterior disc-osteophyte complexes may serve as a valuable postoperative radiographic marker, indicative not only of procedural success but also of restored healthy segmental spinal mechanics. The presence of this finding is both interesting and encouraging. It supports our current understanding that there can be some reversibility of disease pathologies should treatment be delivered early and appropriately. In this case, having anterior osteophyte formation is not irreversible. Moreover, it also demonstrates the possibility of rejuvenation of the mobile spine using CDA in terms of not simply treating the patients\u0026rsquo; symptoms, but also being able to restore the proper mechanics of the degenerated spine. With these results, guidelines should look again at the contraindications of CDA and focus on the need for proper surgical techniques to be able expand the indications of CDA for greater benefit to our patients.\u003c/p\u003e \u003cp\u003eThis study has some limitations. First, its retrospective nature, single-center design, as well as the limited sample size will inherently have some effect on the reliability of the reported results. However, radiological findings will not be influenced by these issues and remain objective proof of our findings. Second, the regression of disc osteophytes was analyzed using radiographic 2D imaging rather than utilizing a volumetric 3D assessment (i.e., using CT). Therefore, osteophyte size evaluation might have been affected by the patient position during X-ray acquisition as well as by the subjective nature of imaging assessment. This we believe will have little impact especially when regression is qualitatively obvious and is trended over time. Third, we caution that the results may not be applicable to every center as the technique of CDR will differ from surgeon-to-surgeon and prosthesis-to-prosthesis. Variation in surgical techniques and prosthesis use has been shown to affect outcomes. Last, while promising in terms of radiological evaluation, the real clinical relevance of osteophyte regression in the setting of CDA still needs to be further demonstrated with larger and longer prospective clinical studies looking at patient reported outcome scores.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eRegression of anterior cervical disc-osteophyte complex following CDA is common with proper surgical technique and prosthesis. This phenomenon highlights the strengths of CDA in stress distribution and restoration of movement in the cervical spine. Its presence can be regarded as a positive feedback interpreted by the body, and may become a useful predictor of satisfactory functional and radiological outcomes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003e \u003cb\u003eCompeting Interests\u003c/b\u003e:\u003c/h2\u003e \u003cp\u003ethe authors declare that they have no competing interests.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003e \u003cb\u003eEthics approval\u003c/b\u003e:\u003c/strong\u003e \u003cp\u003e this study was approved by the local institutional ethics board. As this was a retrospective review of anonymized data, the requirement for informed consent was waived.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003ethe authors received no financial support for the research, authorship, and/or publication of this article.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eE.d.R. and Z.C. conceived the study and drafted the initial manuscript; E.L.K. and A.Q.A.T. contributed to data collection and analysis; T.J.H. and S.L. performed radiological measurements and statistical analysis; D.H.H.W. supervised the project, provided critical revisions, and ensured overall scientific integrity. 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Spine J 18:1779\u0026ndash;1786\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Cervical disc arthroplasty, motion preservation, regression of disc-osteophyte complex, cervical spondylosis, heterotopic ossification","lastPublishedDoi":"10.21203/rs.3.rs-8704317/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8704317/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eCervical disc arthroplasty (CDA) has gained popularity as a suitable alternative to ACDF for treatment of anterior cervical compressive pathologies. Regression of anterior cervical disc osteophyte complex after CDA is a less commonly recognized and understood radiological finding, one which was previously only described following fusion. Our aim is to describe the regression of anterior cervical disc osteophyte complex following CDA, and discuss its potential clinical significance.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eBaseline characteristics, clinical presentation, perioperative details, and postoperative details were collected of patients who underwent CDA with a minimum of 2-year follow up. Presence of implant subsidence, peri-implant fractures, and heterotopic ossification were also recorded. Radiological parameters including pre and postoperative global cervical alignment, segmental range of motion, protrusion of cervical disc-osteophyte complex at each vertebral level.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003e50 patients (122 levels) were analyzed. Regression of anterior cervical disc osteophytes was observed in 92 levels (75%) at 3-month postoperatively, 75 levels (61%) at 1-year postoperatively, and 40 levels (33%) at 2-year postoperatively. Mean osteophyte size significantly decreased from immediate postoperative period up to 1-year follow-up (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.005), with no significant difference in osteophyte size between 1 and 2-year follow-up. Range of motion of C2-7 and operated functional spinal unit improved throughout all 3 follow-up timepoints. Heterotopic ossification was observed up to 35 levels (28%) at 2-year follow-up.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eRegression of anterior cervical disc-osteophyte complex following CDA suggests stress distribution and restoration of movement in the cervical spine, and may be a useful predictor of satisfactory functional and radiological outcomes.\u003c/p\u003e","manuscriptTitle":"Regression of anterior cervical disc-osteophyte complex following artificial disc replacement – A radiological phenomenon","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-22 12:37:08","doi":"10.21203/rs.3.rs-8704317/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c2e35788-c4aa-4607-95ba-2c6805276158","owner":[],"postedDate":"February 22nd, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-15T06:07:03+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-14T13:58:42+00:00","index":19,"fulltext":""},{"type":"reviewerAgreed","content":"111182333063271073671951312718572761561","date":"2026-05-14T10:26:31+00:00","index":18,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T06:28:12+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-22 12:37:08","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8704317","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8704317","identity":"rs-8704317","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}