Risk factors for augmented vertebrae recollapse after percutaneous kyphoplasty for osteoporotic vertebral compression fractures

Risk factors for augmented vertebrae recollapse after percutaneous kyphoplasty for osteoporotic vertebral compression fractures | 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 Risk factors for augmented vertebrae recollapse after percutaneous kyphoplasty for osteoporotic vertebral compression fractures Ming-Wei Dong, Jun Lei, Jun Yang, Yue Pan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6983662/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 11 You are reading this latest preprint version Abstract Objectives: The purpose of this study was to analyze the risk factors for recollapse of augmented vertebrae after percutaneous kyphoplasty (PKP). Methods: Patients who had been treated with bilateral PKP and met the inclusion criteria were retrospectively reviewed. We assessed the following potential risk factors for augmented vertebrae recollapse: age, gender, weight, height, body mass index (BMI), preoperative T-score in bone mineral density (BMD), fracture spine level, follow-up duration, reduction rate (RR), reduction angle (RA), cement volume, preoperative intravertebral cleft (IVC), cement contact with endplates, cement distribution, and the cross-sectional area (CSA) and percent fatty infiltration area (pFIA) of the multifidus. Univariate and multivariate regression analyses were progressively performed to identify the risk factors for augmented vertebrae recollapse. Results: A total of 112 patients were enrolled in the study. There were 27 (24.1%) patients in the recollapse group. Multivariate regression analysis identified preoperative IVC, separated cement distribution, higher RR, greater RA, and larger pFIA of the multifidus as the risk factors for the augmented vertebrae recollapse.Larger CSA of the multifidus was a protective factor for vertebral body recompression. Receiver operating characteristic (ROC) curve analysis showed that the areas under the ROC curve of higher RR, greater RA, larger pFIA, and larger CSA were 0.710, 0.649, 0.714,and 0.754, respectively. Conclusions: Preoperative IVC, separated cement distribution, higher RR, greater RA, and larger FIA of the multifidus are independent risk factors for the augmented vertebrae recollapse. Larger CSA of the multifidus is a protective factor for the augmented vertebrae recollapse. Percutaneous kyphoplasty Vertebrae recollapse Paraspinal muscle Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Osteoporosis is characterized by reduced bone mass, degeneration of bone microstructure, and decline in bone density and bone quality, and it is one of the main reasons of fracture in elderly patients. It is estimated that every year 1.4 million new osteoporotic vertebral compression fractures (OVCFs) occur in the world. 1 Not only can OVCFs cause severe back pain, limited activity, progressive spinal deformity, and increased mortality, but they also bring a heavy economic burden to the patients' families 2 – 4 . According to previous literature, OVCFs account for about 45% of osteoporotic fractures and are a common fracture type in the elderly. 5 The treatment of OVCFs mainly includes conservative management and surgical treatment. Most OVCFs are successfully treated through conservative methods, such as bed rest, analgesics, anti-osteoporosis treatment, and physical therapy. However, nearly 30% of patients still experience persistent pain and limited physical function. 6 – 8 Percutaneous kyphoplasty (PKP) was designed by Wong and Reiley and approved for clinical use in 1998. 9 It is a minimally invasive surgery for the treatment of symptomatic OVCFs. 2 A large number of clinical studies have shown that compared with conservative treatment, PKP can quickly relieve pain, improve physical function, and restore vertebral height. 10 , 11 Due to this, PKP has widely been used in clinical practice. However, many studies have reported augmented vertebrae recollapse after a period of postoperative follow-up, which may lead to a more serious fracture and damage to the spinal cord, and usually requires further treatment. 12 – 16 This situation may eventually lead to problems that reduce quality of life, including lower back pain, vertebral fractures, nerve compression, and spinal deformities. Numerous clinical studies have reported various factors related to the augmented vertebrae recollapse after PKP, such as preoperative intravertebral cleft (IVC), small volume of cement injection, cement distribution pattern, excessive vertebral height restoration, and no polymethyl methacrylate (PMMA)–endplate contact (NPEC). 12 – 15 However, some risk factors may have been missed due to the small sample population, and some of the factors are still controversial or neglected. Therefore, the purpose of this study was to analyze the risk factors for recollapse of augmented vertebrae after PKP. Materials and methods Patients All patients gave informed consent to participate. From March 2019 to May 2021, we retrospectively reviewed 512 patients with OVCFs treated with PKP. The inclusion criteria were as follows: 1) single-level vertebral compression fracture treated with PKP; 2) completed radiological studies, including preoperative, postoperative, and latest follow-up; 3) if the patient's bone mineral density (BMD) T-score was less than − 1.0 or − 2.5, the patient was diagnosed with osteopenia or osteoporosis, respectively; 4) postoperative regular anti-osteoporosis treatment during the follow-up period. The patients took alendronate (70 mg/week), calcium tablets (600–1200 mg/day), and calcitriol (0.25–0.5 µg/day) after surgery. The exclusion criteria were as follows: 1) vertebral compression fractures at two or more levels; 2) compression fracture caused by other factors, such as pathological fractures due to spinal infection or tumor; 3) brain disease or cognitive impairment that prevents independent communication. There were a total of 512 patients, of which 115 were treated conservatively. 239 patients were excluded due to loss of follow-up, lack of necessary imaging data, incomplete bone density, or lack of long-term anti osteoporosis treatment. 46 patients were excluded due to multiple fractures or pathological fractures. Finally, 112 patients were enrolled. Operative technique When determining osteoporotic vertebral compression fractures, all patients were given conservative treatments such as bed rest, wearing braces, pain relief, and anti-osteoporosis. If persistent pain or fracture progression was found after 1–2 weeks of non-surgical treatment, surgical treatment is performed. The patient was placed in the prone position on the operating table and given general or local anesthesia. Then, bone puncture trocars were placed on both sides of the lateral edge of the pedicle at the fracture level, and gradually passed through the pedicle into the anterior third of the vertebra under C-arm guidance. The bone cement used in the surgery is polymethylmethacrylate (Tianjin Synthetic Material Research Institute, Tianjin, China). Next, using an inflatable bone balloon, PMMA was carefully injected into the fractured vertebra. When the cement leaked into extraosseous structures or vein, or the cement reached the vertebral cortical edge, the injection was stopped. The patient was placed in the prone position for 10 to 15 minutes after the operation so that the PMMA could solidify. The patient had to wear a brace for at least one month to assist in walking. Radiographic assessment Evaluation of reduction angle and reduction rate Vertebral height and kyphotic angle were measured preoperatively and on the first postoperative day. The kyphosis angle was measured between the upper endplate of the upper vertebra and the lower endplate of the lower vertebra (Fig. 1 ). The reduction angle (RA) was defined as the difference of kyphotic angle before PKP and that on the first day after PKP. The vertebral compression rate (CR) was defined as the ratio of the central height of the injured vertebra to the average central height of the proximal and distal adjacent vertebrae (Fig. 2 ). The reduction rate (RR) was defined as the difference between the CR before PKP and that on the first day after PKP. Evaluation of cement distribution pattern The cement distribution pattern in the fractured vertebra was evaluated using postoperative plain radiographs. Based on the cement distribution pattern, the patients were divided into two patterns, namely the separated distribution group and confluent distribution group (Fig. 3 ). Evaluation of the type of contact between PMMA and vertebral endplates The type of contact between PMMA and vertebral endplates was evaluated by postoperative radiography, and the patients were divided into the following four types: PMMA connected with both the upper endplate and the lower endplate (group 1); PMMA only in contact with the upper endplate (group 2); PMMA only in contact with the lower endplate (group 3); and PMMA not in contact with any of the endplates (group 4) (Fig. 4 ). Evaluation of preoperative IVC We evaluated preoperative IVC by preoperative magnetic resonance imaging (MRI) or computed tomography (CT). The IVC sign was shown as an intravertebral gas-filled/fluid shadow on CT, and hypointensity on T1-weighted image and hypointensity/hyperintensity on T2-weighted image (Fig. 5 ). Evaluation of the fatty infiltration area (FIA) and cross-sectional area (CSA) of paravertebral muscles The paravertebral muscle of interest in this research was multifidus. The multifidus signal intensity was detected at L4/5 segment in T2W1 cross-section. First, we set up the scale pixel/cm, converted the pixels into centimeters, and converted each image into an 8-bit gray image. Next, we used ImageJ (Version 1.43u, National Institutes of Health, USA) to outline the CSA of the multifidus. Then, the signal was quantized by threshold technology to measure the fatty infiltration area (FIA). Finally, we calculated the percent FIA (pFIA) as the FIA divided by the CSA (Fig. 6 ). 17 , 18 Evaluation of recollapse of the augmented vertebrae We defined the augmented vertebrae recollapse as the decrease in the central height of the vertebral body by more than 2 mm in the latest follow-up relative to the central height of the vertebra on the first day after operation on the plain radiograph. Factors for recollapse The potential risk factors, including age, sex, height, weight, body mass index (BMI), follow-up duration, preoperative T-score in BMD, fracture spine level, RR, RA, cement volume, preoperative IVC, cement contact with endplates, cement distribution, and the CSA and FIA of the multifidus, were recorded. Pain was assessed by visual analogue scale (VAS) before operation, on the first day after PKP, and at the latest follow-up. Statistical analysis We used t -tests for independent samples or Mann–Whitney U tests to compare quantitative variables between the recollapse group and maintaining group. Categorical variables were compared by Fisher’s exact test or chi-square test. The VAS scores of the maintaining group and recollapse group were analyzed and compared by a covariance model. Then, we used multiple logistic regression analysis to determine the independent factors that were helpful in predicting the recollapse of augmented vertebrae. In addition, we established a receiver operating characteristic (ROC) curve and determined the cutoff value of all important risk factors with quantitative data. The p value lower than 0.05 was considered statistically significant. The statistical analysis was conducted in SPSS, version 26.0 (SPSS, Inc., Chicago, IL, USA). Results A total of 112 patients, including 16 men and 96 women, met the study criteria and were enrolled in the study. All patients successfully underwent surgery. Table 1 summarizes the comparison of the patients’ demographic data between maintaining and recollapse groups. The average age was 68.91 ± 8.39 years (69.60 ± 8.34 years in the maintaining group vs. 66.74 ± 8.35 years in the recollapse group; p = 0.124). The average follow-up time of the maintaining group and recollapse group was 11.89 ± 1.3 months and 11.96 ± 1.34 months, respectively ( p = 0.813). The operative levels were T6–T10 (6 cases), T11–L2 (94 cases), and L3–L5 (12 cases). There were no significant differences in gender, age, fracture spine level, follow-up duration, preoperative T-score in BMD, weight, height, and BMI ( p > 0.05) between the recollapse and maintaining groups (Table 1 ). Table 1 Demographics of Patients in Maintaining and Recollapse Groups Demographic Categories Maintaining Group (n = 85) Recollapse Group (n = 27) P Value Age (year) 69.60 ± 8.34 66.74 ± 8.35 0.124 Gender Male Female 10(12%) 75(88%) 6(22%) 21(78%) 0.300 Treated level T6-T10 T11-L2 L3-L5 5(6%) 73(86%) 7(8%) 1(4%) 21(78%) 5(18%) 0.307 Follow-up duration (months) 11.89 ± 1.3 11.96 ± 1.34 0.813 BMD (preoperative T-scores) -3.4 ± 1.1 -3.1 ± 1.0 0.506 Cement volume (ml) 3.4 ± 1.1 3.6 ± 0.9 0.276 preoperative IVC Yes No 2(2%) 83(98%) 10(37%) 17(63%) < 0.001 Cement contact with endplates Both Crania Caudal Neither 61(72%) 17(20%) 2(2%) 5(6%) 21(78%) 3(11%) 1(4%) 2(7%) 0.664 Cement distribution Separate Connect 16(19%) 69(81%) 14(52%) 13(48%) 0.001 Reduction rate (%) 14.0 ± 8.6 21.1 ± 9.4 < 0.001 Reduction angle(°) 3.0 ± 4.2 5.0 ± 3.3 0.020 Cross-sectional area(mm 2 ) 824.1 ± 137.9 700.3 ± 119. 1 < 0.001 Percent Fatty infiltration area(%) 24.9 ± 8.8 32.7 ± 11.2 0.001 Body weight (kg) 56.11 ± 6.67 58.63 ± 8.40 0.111 Body height (cm) 157.74 ± 6.14 158.67 ± 7.9 0.527 There was no significant difference in VAS pain score between the maintaining and recollapse groups in the preoperative and postoperative evaluation (Table 2 ). However, in the latest follow-up, VAS score of the recollapse group was significantly higher than that of the maintaining group ( p = 0.026). As shown in Table 3 , in the recollapse group, the vertebral height ratio (VHR) after PKP increased from 69.49%±9.71–90.40%±7.09% but decreased to 78.03%±8.56% at the latest follow-up. The kyphosis angle decreased from 17.03°±10.13° to 12.05°±8.66° and decreased to 15.34°±8.74° at the latest follow-up. In the maintaining group, the VHR and kyphosis angle did not change significantly during the follow-up. Table 2 VAS Pain Scores for Recollapse and Maintaining Patient Groups VAS Pain Scores Preoperative Pain Postoperative Pain Post VS Pre Pain at Last Last VS PRE Recollapse 7.6 ± 0.9 1.9 ± 0.8 P = 0.000* 2.7 ± 0.9 P = 0.000* Maintaining 7.5 ± 1.1 2.1 ± 1.0 P = 0.000* 2.2 ± 1.1 P = 0.000* Maintaining Versus Recollapse P = 0.567† P = 0.368 ‡ P = 0.026 ‡ *Pairwise t test. †Group/independent t test. ‡Analysis of covariance adjusted for baseline value. Table 3 Radiographic Outcomes in the Recollapse and Maintaining Patient Groups Radiographic Outcomes Preoperative Postoperative At Last Follow-Up Kyphotic angle(°) Recollapse Maintaining 17.03 ± 10.13 14.20 ± 8.01 12.05 ± 8.66 11.26 ± 6.99 15.34 ± 8.74 12.40 ± 7.42 Central vertebral height ratio (%) Recollapse Maintaining 69.49 ± 9.71 76.52 ± 12.65 90.40 ± 7.09 90.49 ± 10.70 78.03 ± 8.56 87.93 ± 10.54 Univariate analysis showed that the bone cement distribution patterns (p = 0.001), preoperative IVC (p < 0.001), RR (p < 0.001), RA (p = 0.020), and CSA (p < 0.001) and pFIA (p = 0.001) of the multifidus showed statistically significant differences between the two groups (Table 1 ). Multivariate logistic regression analysis showed that preoperative IVC (OR = 34.005; 95% CI 2.861–404.175; p = 0.005), separated cement distribution (OR = 7.402; 95% CI 1.402–39.074; p = 0.018), higher RR (OR = 1.122; 95% CI 1.025–1.229; p = 0.01), greater RA (OR = 1.421; 95% CI 1.092–1.850; p = 0.009), and larger pFIA of the multifidus (OR = 1.082; 95% CI 1.002–1.169; p = 0.044) were the independent risk factors for the augmented vertebrae recollapse. Larger CSA of the multifidus (OR = 0.986; 95% CI 0.978–0.994; p = 0.001) was the protective factor for the augmented vertebrae recollapse (Table 4 ). Table 4 Outcome of multivariate logistic regression analysis OR (95% CI) P value preoperative IVC 34.005(2.861-404.175) 0.005 Cement distribution 7.402(1.402–39.074) 0.018 Reduction rate 1.122(1.025–1.229) 0.012 Reduction angle 1.421(1.092–1.850) 0.009 Cross-sectional area 0.986(0.978–0.994) 0.001 Fatty infiltration area 1.082(1.002–1.169) 0.044 The area under the ROC curve (AUC) of RR as a predictor of recollapse was 0.710 ( p = 0.002), with a cutoff value of 12.42%, sensitivity of 87.5%, and specificity of 51.5%. The AUC of RA as a predictor of recollapse was 0.649 ( p = 0.031), with a cutoff value of 3.38°, sensitivity of 70.8%, and specificity of 57.4%. The AUC of pFIA as a predictor of recollapse was 0.714 ( p = 0.002), with the cutoff value of 30.24%, sensitivity of 66.7%, and specificity of 76.5%. The AUC of CSA as a predictor of recollapse was 0.754 ( p = 0.000), with a cutoff value of 744.5 mm 2 , sensitivity of 75.0%, and specificity of 72.1% (Fig. 7 ). Discussion PKP is a minimally invasive surgery used to treat OVCFs safely and effectively. 2 It can quickly relieve pain, improve physical function, and restore vertebral height. 10 , 11 However, according to previous studies, 12 , 14 , 19 – 21 some patients experience augmented vertebrae recollapse during follow-up, with a decrease in vertebral height and aggravation of local kyphosis, which usually requires further treatment. Augmented vertebrae recollapse may cause recurrent, stubborn back pain and render conservative treatment ineffective due to the change in facet joint load and progressive collapse. This situation eventually leads to problems that reduce quality of life. Therefore, the purpose of this research was used to retrospectively analyze the risk factors for recollapse of the augmented vertebrae. According to previous studies, 22 – 24 IVC is the nonunion area of fracture pseudoarthritis. The presence of IVC has been described as a risk factor for the recollapse of augmented vertebrae. 14 , 19 Our results are compatible with those from the prior studies. Wang et al. 19 reported that IVC was an important risk factor for recollapse. Preoperative IVC was present in 26 of the 79 patients with vertebral fracture in the recollapse group (32.9%) and in 25 of the 124 patients with vertebral fracture in the maintaining group (20.2%). There was significant difference in preoperative IVC between the recollapse group and maintaining group ( p < 0.05). Kim et al. 14 obtained similar results. In a fractured vertebra without IVC, the balloon can compress the adjacent bone to give space to PMMA and improve bone density of the compression area. After PMMA is injected, some of PMMA infiltrates into the bone marrow cavity under pressure, forming an interdigitated structure. If the interdigital PMMA gets in touch with the endplate, it can support the endplate to bear the load. However, in a fractured vertebral body with IVC, the balloon easily expands in the IVC area without compressing the adjacent bone. PMMA only fills the space formed by the balloon, and does not form an interdigitated pattern. Therefore, the endplate is only pushed by PMMA, and under the effect of stress shielding, the augmented vertebrae are prone to recollapse. In this study, higher RR and greater RA were the risk factors for augmented vertebrae recollapse. Niu et al. 12 reported that vertebral height recovery and LKA correction significantly correlated with recompression ( p < 0.05), and multiple binary logistic regression analysis demonstrated that the degree of VHR (OR = 1.260; p < 0.001) positively correlated with the recollapse of augmented vertebrae. Wang et al. 19 showed that higher vertebral height recovery after PKP was more likely to lead to recollapse. Our results are consistent with previous research. 12 , 19 The reasons for this result may be that higher RR and greater RA can lead to the increased paravertebral soft tissue tension, thereby resulting in more instability of the fracture segments or the increased mechanical load on the augmented vertebrae. In addition, Heo et al. 25 suggested that in the augmented vertebrae, especially those with solid block cement distribution or preoperative IVC, excessive vertebral height restoration might promote osteonecrosis. However, there was no unified conclusion on the optimal reduction rate of vertebral height and reduction angle, which requires further research. In PVP, PMMA fills the cancellous bone of the fractured vertebra in an interdigitated manner. The distribution pattern of the cement is mainly divided into two modes, namely solid and trabecular. However, in PKP, PMMA is composed of one or two solid masses. Thus, in this study, we divided the cement distribution pattern into the separated group and confluent group. Previous studies have mainly reported the relationship between the distribution pattern of cement and pain residue after PKP. 26 , 27 He et al. 27 showed that the pain relief effect was better in the confluent group than in the separated group. Li et al. 26 demonstrated that the quality of life of the separated group was significantly worse than that of the confluent cement distribution group. However, to date, no relevant research has mentioned the relationship between the distribution of separated and confluent cement and augmented vertebrae recollapse. In this study, we found that the separation distribution rate of recollapse group was higher than that of the maintaining group, and multivariate logistic regression analysis revealed that the distribution pattern of separated cement was an independent risk factor for the recollapse of augmented vertebrae. Relevant studies have confirmed that back muscles are important for spine stability. 28 However, the relationship between CSA and pFIA of paraspinal muscles and augmented vertebrae recollapse has rarely been mentioned in prior research. In this study, we found that larger pFIA of multifidus was an independent risk factor for the augmented vertebrae recollapse. Larger CSA of multifidus was identified as a protective factor for the augmented vertebrae recollapse. The reason may be that strong paravertebral muscles can reduce the stress between vertebrae, intervertebral disc, and facet joints, playing an irreplaceable role under higher load. In addition, there was a correlation between paraspinal muscle atrophy and muscle fatty infiltration with spinal and pelvic parameters, and the spine and muscles can interact to maintain sagittal balance in the human body. 29 Patients with paraspinal muscle atrophy and fat infiltration may lead to bending and further sagittal imbalance of the spine, which can increase weight load and increase the risk of re collapse of the fractured vertebral body after surgery. Previous studies have shown that strengthening back muscle movement after surgery can improve body function, reduce pain, promote spinal height recovery, and maintain bone density. 30 Therefore, it was also crucial to evaluate muscle quality and strengthen exercises for the lower back muscles. The current research has some limitations. First, because the number of patients in the two groups were relatively small and the samples were from the same institution, the study results are not generalizable. Second, the CSA and FIA of the multifidus were evaluated on MRI. Therefore, a blind assessment was conducted by three experienced specialists to minimize bias. Third, there is no gold standard to evaluate the recollapse of augmented vertebrae. Wang et al. 19 defined the augmented vertebrae recollapse as the reduction in the central vertebral body height by more than 2 mm in the last follow-up. Kim et al. 14 defined the augmented vertebrae recollapse as the height of the postoperative anterior body greater than the final anterior body height by more than 1.0 mm. Niu et al. 12 adopted the criterion of 4-mm reduced height of the vertebral body. In addition, ROC curve needs to determine the "diagnostic authenticity" of the study case. Due to the lack of the gold standard for vertebral collapse, the results will also deviate. Conclusions In conclusion, during follow-up, the augmented vertebrae height after PKP was usually partially offset by recollapse. Preoperative IVC, separated cement distribution, higher RR, greater RA, and larger pFIA of the multifidus were identified as the independent risk factors for the augmented vertebrae recollapse. Larger CSA of the multifidus was identified as the protective factor for the augmented vertebrae recollapse. Abbreviations BMI Body mass index CT Computed tomography MR Magnetic resonance OVCF Osteoporotic vertebral compression fracture PKP Percutaneous kyphoplasty PMMA Polymethyl methacrylate VAS Visual Analog Scale VHR Vertebral height ratio Declarations Ethics approval and consent to participate This study protocol was reviewed and approved by the Ethics Committee of the The First People's Hospital of Jiashan County, Zhejiang Province. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Consent for publication Not applicable. Availability of data and materials The datasets generated during and analyzed during the current study are not publicly available due to privacy and ethical concerns but are available from the corresponding author on reasonable request. Competing Interests The authors declare that they have no competing interests. Funding This work has no funding support. Authors' contributions M.D. conducted data analysis and wrote the initial draft. J.L. reviewed and revised the initial draft. J.Y. conducted data collection. Y.P. designed the ideas for the paper.All authors reviewed the manuscript. Acknowledgements Not applicable. Clinical trial:number Not applicable References Johnell O, Kanis JA. 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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-6983662","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":483017117,"identity":"6a5f97da-d86b-4569-ada5-ba7310ea85fb","order_by":0,"name":"Ming-Wei Dong","email":"","orcid":"","institution":"The First People's Hospital of Jiashan County","correspondingAuthor":false,"prefix":"","firstName":"Ming-Wei","middleName":"","lastName":"Dong","suffix":""},{"id":483017118,"identity":"137013f3-db58-483a-800d-9304535fc91d","order_by":1,"name":"Jun Lei","email":"","orcid":"","institution":"The First People's Hospital of Jiashan County","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Lei","suffix":""},{"id":483017119,"identity":"80631c13-59f7-418c-b1fd-a11b8e7f333b","order_by":2,"name":"Jun Yang","email":"","orcid":"","institution":"The First People's Hospital of Jiashan County","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Yang","suffix":""},{"id":483017120,"identity":"1760248a-d125-4628-9abf-f5290709e6e0","order_by":3,"name":"Yue Pan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYBACNv7m4x8+VNTIsbE3H3yQUFFDWAufxLE0xhlnjhnz8xxLNnhw5hhhLXIMOWrMnG3MiTNn5KhJPmxhJsJhDGfYHgOxscGBHLaKxAY2Bv727gT8Wph7jxsXVMjIGRw4e+xG4g4ZBokzZzcQsOVcgvQMkC0H+9JuJJ5hYzCQyCWkJcdAmhfolw2HecwKEtuYidJiBtYys43HjIE4LRLHkg0hgcyWLJFw5hgPQb/I9wNjEByV8o8PfvwBZPC39+LXggF4SFM+CkbBKBgFowArAAByOk0WvOz/ZAAAAABJRU5ErkJggg==","orcid":"","institution":"The First People's Hospital of Jiashan County","correspondingAuthor":true,"prefix":"","firstName":"Yue","middleName":"","lastName":"Pan","suffix":""}],"badges":[],"createdAt":"2025-06-26 12:53:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6983662/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6983662/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86657204,"identity":"75de5d62-75e5-455d-9a68-3954b540bd7f","added_by":"auto","created_at":"2025-07-14 10:22:43","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1142278,"visible":true,"origin":"","legend":"\u003cp\u003eThe kyphotic angle was measured as between the upper endplate of the proximal adjacent vertebra and the lower endplate of the distal adjacent vertebra.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/da2e98f3847ee2baea7d3b62.png"},{"id":86657202,"identity":"ca8e7c7e-ecc6-468e-b9dc-a22b630f8445","added_by":"auto","created_at":"2025-07-14 10:22:43","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1306219,"visible":true,"origin":"","legend":"\u003cp\u003eThe vertebral compression rate (CR) was measured as the ratio of the central height of the injured vertebrae to the average central height of the upper and lower vertebrae. MVH, midline vertebral height.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/134e5c2dfba06b38a7859eb2.png"},{"id":86659216,"identity":"15a9bf82-9d88-4d84-a409-e2585767bc9d","added_by":"auto","created_at":"2025-07-14 10:30:43","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":905199,"visible":true,"origin":"","legend":"\u003cp\u003eseparated cement distribution (A); confluent cement distribution (B).\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/f5f3a25759430ed2482a9be9.png"},{"id":86661341,"identity":"1a72c0d6-385a-4511-ac52-c0e0a6dffed4","added_by":"auto","created_at":"2025-07-14 10:38:43","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":713896,"visible":true,"origin":"","legend":"\u003cp\u003ePMMA was connected with the upper endplate and the lower endplate (A,B); PMMA was only in contact with the upper endplate (C,D); PMMA was only in contact with the lower endplate (E,F); PMMA did not contact either the upper endplate or the lower endplate (G,H).\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/db3b5a3626937aeb757b5ca6.png"},{"id":86657206,"identity":"05f32993-d5ee-40b7-8f18-44a7f4e9416c","added_by":"auto","created_at":"2025-07-14 10:22:43","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":147346,"visible":true,"origin":"","legend":"\u003cp\u003eThe imaging manifestation of preoperative IVC on CT (A and B), T1 WI (C); T2 WI(D).\u003c/p\u003e","description":"","filename":"image5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/f07f0f77d7ab1964e49eaf95.jpeg"},{"id":86659221,"identity":"7ebba9f4-3086-4083-92f7-1172760f4818","added_by":"auto","created_at":"2025-07-14 10:30:43","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":73429,"visible":true,"origin":"","legend":"\u003cp\u003eThe multifidus signal intensity was detected at L4/5 segment in T2W1 cross-section(A). Measurement methods of CSA and FIA of paraspinal muscle(B,C).\u003c/p\u003e","description":"","filename":"image6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/00d662c82fcbe3f4aea35c29.jpeg"},{"id":86659220,"identity":"df52f030-d8fb-4e4a-a8fa-f9ac00fca090","added_by":"auto","created_at":"2025-07-14 10:30:43","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":38470,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver operating characteristic curve for recollapse risk.\u003c/p\u003e","description":"","filename":"image7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/efff0b4d5ff93e8dad3f64c5.jpeg"},{"id":86663011,"identity":"8439f0ea-ef04-4fab-9c61-be28701da94e","added_by":"auto","created_at":"2025-07-14 10:46:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5939948,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6983662/v1/d0e2daa9-e2cb-455f-a1f2-ab3ca645384e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Risk factors for augmented vertebrae recollapse after percutaneous kyphoplasty for osteoporotic vertebral compression fractures","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOsteoporosis is characterized by reduced bone mass, degeneration of bone microstructure, and decline in bone density and bone quality, and it is one of the main reasons of fracture in elderly patients. It is estimated that every year 1.4\u0026nbsp;million new osteoporotic vertebral compression fractures (OVCFs) occur in the world.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e Not only can OVCFs cause severe back pain, limited activity, progressive spinal deformity, and increased mortality, but they also bring a heavy economic burden to the patients' families\u003csup\u003e\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. According to previous literature, OVCFs account for about 45% of osteoporotic fractures and are a common fracture type in the elderly.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eThe treatment of OVCFs mainly includes conservative management and surgical treatment. Most OVCFs are successfully treated through conservative methods, such as bed rest, analgesics, anti-osteoporosis treatment, and physical therapy. However, nearly 30% of patients still experience persistent pain and limited physical function.\u003csup\u003e\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e Percutaneous kyphoplasty (PKP) was designed by Wong and Reiley and approved for clinical use in 1998.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e It is a minimally invasive surgery for the treatment of symptomatic OVCFs.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e A large number of clinical studies have shown that compared with conservative treatment, PKP can quickly relieve pain, improve physical function, and restore vertebral height.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e Due to this, PKP has widely been used in clinical practice.\u003c/p\u003e\u003cp\u003eHowever, many studies have reported augmented vertebrae recollapse after a period of postoperative follow-up, which may lead to a more serious fracture and damage to the spinal cord, and usually requires further treatment.\u003csup\u003e\u003cspan additionalcitationids=\"CR13 CR14 CR15\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e This situation may eventually lead to problems that reduce quality of life, including lower back pain, vertebral fractures, nerve compression, and spinal deformities. Numerous clinical studies have reported various factors related to the augmented vertebrae recollapse after PKP, such as preoperative intravertebral cleft (IVC), small volume of cement injection, cement distribution pattern, excessive vertebral height restoration, and no polymethyl methacrylate (PMMA)\u0026ndash;endplate contact (NPEC).\u003csup\u003e\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e However, some risk factors may have been missed due to the small sample population, and some of the factors are still controversial or neglected. Therefore, the purpose of this study was to analyze the risk factors for recollapse of augmented vertebrae after PKP.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e\u003cb\u003ePatients\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e All patients gave informed consent to participate. From March 2019 to May 2021, we retrospectively reviewed 512 patients with OVCFs treated with PKP. The inclusion criteria were as follows: 1) single-level vertebral compression fracture treated with PKP; 2) completed radiological studies, including preoperative, postoperative, and latest follow-up; 3) if the patient's bone mineral density (BMD) T-score was less than \u0026minus;\u0026thinsp;1.0 or \u0026minus;\u0026thinsp;2.5, the patient was diagnosed with osteopenia or osteoporosis, respectively; 4) postoperative regular anti-osteoporosis treatment during the follow-up period. The patients took alendronate (70 mg/week), calcium tablets (600\u0026ndash;1200 mg/day), and calcitriol (0.25\u0026ndash;0.5 \u0026micro;g/day) after surgery. The exclusion criteria were as follows: 1) vertebral compression fractures at two or more levels; 2) compression fracture caused by other factors, such as pathological fractures due to spinal infection or tumor; 3) brain disease or cognitive impairment that prevents independent communication. There were a total of 512 patients, of which 115 were treated conservatively. 239 patients were excluded due to loss of follow-up, lack of necessary imaging data, incomplete bone density, or lack of long-term anti osteoporosis treatment. 46 patients were excluded due to multiple fractures or pathological fractures. Finally, 112 patients were enrolled.\u003c/p\u003e\u003cp\u003e\u003cb\u003eOperative technique\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWhen determining osteoporotic vertebral compression fractures, all patients were given conservative treatments such as bed rest, wearing braces, pain relief, and anti-osteoporosis. If persistent pain or fracture progression was found after 1\u0026ndash;2 weeks of non-surgical treatment, surgical treatment is performed.\u003c/p\u003e\u003cp\u003eThe patient was placed in the prone position on the operating table and given general or local anesthesia. Then, bone puncture trocars were placed on both sides of the lateral edge of the pedicle at the fracture level, and gradually passed through the pedicle into the anterior third of the vertebra under C-arm guidance. The bone cement used in the surgery is polymethylmethacrylate (Tianjin Synthetic Material Research Institute, Tianjin, China). Next, using an inflatable bone balloon, PMMA was carefully injected into the fractured vertebra. When the cement leaked into extraosseous structures or vein, or the cement reached the vertebral cortical edge, the injection was stopped. The patient was placed in the prone position for 10 to 15 minutes after the operation so that the PMMA could solidify. The patient had to wear a brace for at least one month to assist in walking.\u003c/p\u003e\u003cp\u003e\u003cb\u003eRadiographic assessment\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eEvaluation of reduction angle and reduction rate\u003c/em\u003e\u003c/p\u003e\u003cp\u003eVertebral height and kyphotic angle were measured preoperatively and on the first postoperative day. The kyphosis angle was measured between the upper endplate of the upper vertebra and the lower endplate of the lower vertebra (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The reduction angle (RA) was defined as the difference of kyphotic angle before PKP and that on the first day after PKP. The vertebral compression rate (CR) was defined as the ratio of the central height of the injured vertebra to the average central height of the proximal and distal adjacent vertebrae (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The reduction rate (RR) was defined as the difference between the CR before PKP and that on the first day after PKP.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eEvaluation of cement distribution pattern\u003c/em\u003e\u003c/p\u003e\u003cp\u003eThe cement distribution pattern in the fractured vertebra was evaluated using postoperative plain radiographs. Based on the cement distribution pattern, the patients were divided into two patterns, namely the separated distribution group and confluent distribution group (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eEvaluation of the type of contact between PMMA and vertebral endplates\u003c/em\u003e\u003c/p\u003e\u003cp\u003eThe type of contact between PMMA and vertebral endplates was evaluated by postoperative radiography, and the patients were divided into the following four types: PMMA connected with both the upper endplate and the lower endplate (group 1); PMMA only in contact with the upper endplate (group 2); PMMA only in contact with the lower endplate (group 3); and PMMA not in contact with any of the endplates (group 4) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eEvaluation of preoperative IVC\u003c/em\u003e\u003c/p\u003e\u003cp\u003eWe evaluated preoperative IVC by preoperative magnetic resonance imaging (MRI) or computed tomography (CT). The IVC sign was shown as an intravertebral gas-filled/fluid shadow on CT, and hypointensity on T1-weighted image and hypointensity/hyperintensity on T2-weighted image (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eEvaluation of the fatty infiltration area (FIA) and cross-sectional area (CSA) of paravertebral muscles\u003c/em\u003e\u003c/p\u003e\u003cp\u003eThe paravertebral muscle of interest in this research was multifidus. The multifidus signal intensity was detected at L4/5 segment in T2W1 cross-section. First, we set up the scale pixel/cm, converted the pixels into centimeters, and converted each image into an 8-bit gray image. Next, we used ImageJ (Version 1.43u, National Institutes of Health, USA) to outline the CSA of the multifidus. Then, the signal was quantized by threshold technology to measure the fatty infiltration area (FIA). Finally, we calculated the percent FIA (pFIA) as the FIA divided by the CSA (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eEvaluation of recollapse of the augmented vertebrae\u003c/em\u003e\u003c/p\u003e\u003cp\u003eWe defined the augmented vertebrae recollapse as the decrease in the central height of the vertebral body by more than 2 mm in the latest follow-up relative to the central height of the vertebra on the first day after operation on the plain radiograph.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFactors for recollapse\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe potential risk factors, including age, sex, height, weight, body mass index (BMI), follow-up duration, preoperative T-score in BMD, fracture spine level, RR, RA, cement volume, preoperative IVC, cement contact with endplates, cement distribution, and the CSA and FIA of the multifidus, were recorded. Pain was assessed by visual analogue scale (VAS) before operation, on the first day after PKP, and at the latest follow-up.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eWe used \u003cem\u003et\u003c/em\u003e-tests for independent samples or Mann\u0026ndash;Whitney \u003cem\u003eU\u003c/em\u003e tests to compare quantitative variables between the recollapse group and maintaining group. Categorical variables were compared by Fisher\u0026rsquo;s exact test or chi-square test. The VAS scores of the maintaining group and recollapse group were analyzed and compared by a covariance model. Then, we used multiple logistic regression analysis to determine the independent factors that were helpful in predicting the recollapse of augmented vertebrae. In addition, we established a receiver operating characteristic (ROC) curve and determined the cutoff value of all important risk factors with quantitative data. The \u003cem\u003ep\u003c/em\u003e value lower than 0.05 was considered statistically significant. The statistical analysis was conducted in SPSS, version 26.0 (SPSS, Inc., Chicago, IL, USA).\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 112 patients, including 16 men and 96 women, met the study criteria and were enrolled in the study. All patients successfully underwent surgery. Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the comparison of the patients\u0026rsquo; demographic data between maintaining and recollapse groups. The average age was 68.91\u0026thinsp;\u0026plusmn;\u0026thinsp;8.39 years (69.60\u0026thinsp;\u0026plusmn;\u0026thinsp;8.34 years in the maintaining group vs. 66.74\u0026thinsp;\u0026plusmn;\u0026thinsp;8.35 years in the recollapse group; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.124). The average follow-up time of the maintaining group and recollapse group was 11.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 months and 11.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34 months, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.813). The operative levels were T6\u0026ndash;T10 (6 cases), T11\u0026ndash;L2 (94 cases), and L3\u0026ndash;L5 (12 cases). There were no significant differences in gender, age, fracture spine level, follow-up duration, preoperative T-score in BMD, weight, height, and BMI (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) between the recollapse and maintaining groups (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDemographics of Patients in Maintaining and Recollapse Groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDemographic Categories\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMaintaining Group (n\u0026thinsp;=\u0026thinsp;85)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRecollapse Group (n\u0026thinsp;=\u0026thinsp;27)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge (year)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e69.60\u0026thinsp;\u0026plusmn;\u0026thinsp;8.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e66.74\u0026thinsp;\u0026plusmn;\u0026thinsp;8.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.124\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGender\u003c/p\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e10(12%)\u003c/p\u003e\n \u003cp\u003e75(88%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e6(22%)\u003c/p\u003e\n \u003cp\u003e21(78%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.300\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTreated level\u003c/p\u003e\n \u003cp\u003eT6-T10\u003c/p\u003e\n \u003cp\u003eT11-L2\u003c/p\u003e\n \u003cp\u003eL3-L5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e5(6%)\u003c/p\u003e\n \u003cp\u003e73(86%)\u003c/p\u003e\n \u003cp\u003e7(8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e1(4%)\u003c/p\u003e\n \u003cp\u003e21(78%)\u003c/p\u003e\n \u003cp\u003e5(18%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.307\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFollow-up duration (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.813\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBMD (preoperative T-scores)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-3.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.506\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCement volume (ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.276\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003epreoperative IVC\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e2(2%)\u003c/p\u003e\n \u003cp\u003e83(98%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e10(37%)\u003c/p\u003e\n \u003cp\u003e17(63%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026lt;\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCement contact with endplates\u003c/p\u003e\n \u003cp\u003eBoth\u003c/p\u003e\n \u003cp\u003eCrania\u003c/p\u003e\n \u003cp\u003eCaudal\u003c/p\u003e\n \u003cp\u003eNeither\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e61(72%)\u003c/p\u003e\n \u003cp\u003e17(20%)\u003c/p\u003e\n \u003cp\u003e2(2%)\u003c/p\u003e\n \u003cp\u003e5(6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e21(78%)\u003c/p\u003e\n \u003cp\u003e3(11%)\u003c/p\u003e\n \u003cp\u003e1(4%)\u003c/p\u003e\n \u003cp\u003e2(7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.664\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCement distribution\u003c/p\u003e\n \u003cp\u003eSeparate\u003c/p\u003e\n \u003cp\u003eConnect\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e16(19%)\u003c/p\u003e\n \u003cp\u003e69(81%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e14(52%)\u003c/p\u003e\n \u003cp\u003e13(48%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReduction rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14.0\u0026thinsp;\u0026plusmn;\u0026thinsp;8.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e21.1\u0026thinsp;\u0026plusmn;\u0026thinsp;9.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReduction angle(\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.020\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCross-sectional area(mm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e824.1\u0026thinsp;\u0026plusmn;\u0026thinsp;137.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e700.3\u0026thinsp;\u0026plusmn;\u0026thinsp;119. 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePercent Fatty infiltration area(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24.9\u0026thinsp;\u0026plusmn;\u0026thinsp;8.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.7\u0026thinsp;\u0026plusmn;\u0026thinsp;11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBody weight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e56.11\u0026thinsp;\u0026plusmn;\u0026thinsp;6.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e58.63\u0026thinsp;\u0026plusmn;\u0026thinsp;8.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.111\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBody height (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e157.74\u0026thinsp;\u0026plusmn;\u0026thinsp;6.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e158.67\u0026thinsp;\u0026plusmn;\u0026thinsp;7.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.527\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThere was no significant difference in VAS pain score between the maintaining and recollapse groups in the preoperative and postoperative evaluation (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). However, in the latest follow-up, VAS score of the recollapse group was significantly higher than that of the maintaining group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.026). As shown in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, in the recollapse group, the vertebral height ratio (VHR) after PKP increased from 69.49%\u0026plusmn;9.71\u0026ndash;90.40%\u0026plusmn;7.09% but decreased to 78.03%\u0026plusmn;8.56% at the latest follow-up. The kyphosis angle decreased from 17.03\u0026deg;\u0026plusmn;10.13\u0026deg; to 12.05\u0026deg;\u0026plusmn;8.66\u0026deg; and decreased to 15.34\u0026deg;\u0026plusmn;8.74\u0026deg; at the latest follow-up. In the maintaining group, the VHR and kyphosis angle did not change significantly during the follow-up.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eVAS Pain Scores for Recollapse and Maintaining Patient Groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVAS Pain Scores\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePreoperative Pain\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePostoperative Pain\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePost VS Pre\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePain at Last\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLast VS PRE\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRecollapse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintaining\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintaining\u003c/p\u003e\n \u003cp\u003eVersus\u003c/p\u003e\n \u003cp\u003eRecollapse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.567\u0026dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.368 \u0026Dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eP\u0026thinsp;=\u0026thinsp;0.026 \u0026Dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*Pairwise t test.\u003c/p\u003e\n\u003cp\u003e\u0026dagger;Group/independent t test.\u003c/p\u003e\n\u003cp\u003e\u0026Dagger;Analysis of covariance adjusted for baseline value.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRadiographic Outcomes in the Recollapse and Maintaining Patient Groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRadiographic Outcomes\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePreoperative\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePostoperative\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAt Last Follow-Up\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKyphotic angle(\u0026deg;)\u003c/p\u003e\n \u003cp\u003eRecollapse\u003c/p\u003e\n \u003cp\u003eMaintaining\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17.03\u0026thinsp;\u0026plusmn;\u0026thinsp;10.13\u003c/p\u003e\n \u003cp\u003e14.20\u0026thinsp;\u0026plusmn;\u0026thinsp;8.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e12.05\u0026thinsp;\u0026plusmn;\u0026thinsp;8.66\u003c/p\u003e\n \u003cp\u003e11.26\u0026thinsp;\u0026plusmn;\u0026thinsp;6.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e15.34\u0026thinsp;\u0026plusmn;\u0026thinsp;8.74\u003c/p\u003e\n \u003cp\u003e12.40\u0026thinsp;\u0026plusmn;\u0026thinsp;7.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCentral vertebral height ratio (%)\u003c/p\u003e\n \u003cp\u003eRecollapse\u003c/p\u003e\n \u003cp\u003eMaintaining\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e69.49\u0026thinsp;\u0026plusmn;\u0026thinsp;9.71\u003c/p\u003e\n \u003cp\u003e76.52\u0026thinsp;\u0026plusmn;\u0026thinsp;12.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e90.40\u0026thinsp;\u0026plusmn;\u0026thinsp;7.09\u003c/p\u003e\n \u003cp\u003e90.49\u0026thinsp;\u0026plusmn;\u0026thinsp;10.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e78.03\u0026thinsp;\u0026plusmn;\u0026thinsp;8.56\u003c/p\u003e\n \u003cp\u003e87.93\u0026thinsp;\u0026plusmn;\u0026thinsp;10.54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eUnivariate analysis showed that the bone cement distribution patterns (p\u0026thinsp;=\u0026thinsp;0.001), preoperative IVC (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), RR (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), RA (p\u0026thinsp;=\u0026thinsp;0.020), and CSA (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and pFIA (p\u0026thinsp;=\u0026thinsp;0.001) of the multifidus showed statistically significant differences between the two groups (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Multivariate logistic regression analysis showed that preoperative IVC (OR\u0026thinsp;=\u0026thinsp;34.005; 95% CI 2.861\u0026ndash;404.175; p\u0026thinsp;=\u0026thinsp;0.005), separated cement distribution (OR\u0026thinsp;=\u0026thinsp;7.402; 95% CI 1.402\u0026ndash;39.074; p\u0026thinsp;=\u0026thinsp;0.018), higher RR (OR\u0026thinsp;=\u0026thinsp;1.122; 95% CI 1.025\u0026ndash;1.229; p\u0026thinsp;=\u0026thinsp;0.01), greater RA (OR\u0026thinsp;=\u0026thinsp;1.421; 95% CI 1.092\u0026ndash;1.850; p\u0026thinsp;=\u0026thinsp;0.009), and larger pFIA of the multifidus (OR\u0026thinsp;=\u0026thinsp;1.082; 95% CI 1.002\u0026ndash;1.169; p\u0026thinsp;=\u0026thinsp;0.044) were the independent risk factors for the augmented vertebrae recollapse. Larger CSA of the multifidus (OR\u0026thinsp;=\u0026thinsp;0.986; 95% CI 0.978\u0026ndash;0.994; p\u0026thinsp;=\u0026thinsp;0.001) was the protective factor for the augmented vertebrae recollapse (Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eOutcome of multivariate logistic regression analysis\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOR (95% CI)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003epreoperative IVC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.005(2.861-404.175)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCement distribution\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.402(1.402\u0026ndash;39.074)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReduction rate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.122(1.025\u0026ndash;1.229)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReduction angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.421(1.092\u0026ndash;1.850)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.009\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCross-sectional area\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.986(0.978\u0026ndash;0.994)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFatty infiltration area\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.082(1.002\u0026ndash;1.169)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.044\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe area under the ROC curve (AUC) of RR as a predictor of recollapse was 0.710 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002), with a cutoff value of 12.42%, sensitivity of 87.5%, and specificity of 51.5%. The AUC of RA as a predictor of recollapse was 0.649 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.031), with a cutoff value of 3.38\u0026deg;, sensitivity of 70.8%, and specificity of 57.4%. The AUC of pFIA as a predictor of recollapse was 0.714 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002), with the cutoff value of 30.24%, sensitivity of 66.7%, and specificity of 76.5%. The AUC of CSA as a predictor of recollapse was 0.754 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.000), with a cutoff value of 744.5 mm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, sensitivity of 75.0%, and specificity of 72.1% (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003ePKP is a minimally invasive surgery used to treat OVCFs safely and effectively.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e It can quickly relieve pain, improve physical function, and restore vertebral height.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e However, according to previous studies,\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e some patients experience augmented vertebrae recollapse during follow-up, with a decrease in vertebral height and aggravation of local kyphosis, which usually requires further treatment. Augmented vertebrae recollapse may cause recurrent, stubborn back pain and render conservative treatment ineffective due to the change in facet joint load and progressive collapse. This situation eventually leads to problems that reduce quality of life. Therefore, the purpose of this research was used to retrospectively analyze the risk factors for recollapse of the augmented vertebrae.\u003c/p\u003e\u003cp\u003eAccording to previous studies,\u003csup\u003e\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e IVC is the nonunion area of fracture pseudoarthritis. The presence of IVC has been described as a risk factor for the recollapse of augmented vertebrae.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e Our results are compatible with those from the prior studies. Wang et al.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e reported that IVC was an important risk factor for recollapse. Preoperative IVC was present in 26 of the 79 patients with vertebral fracture in the recollapse group (32.9%) and in 25 of the 124 patients with vertebral fracture in the maintaining group (20.2%). There was significant difference in preoperative IVC between the recollapse group and maintaining group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Kim et al.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e obtained similar results. In a fractured vertebra without IVC, the balloon can compress the adjacent bone to give space to PMMA and improve bone density of the compression area. After PMMA is injected, some of PMMA infiltrates into the bone marrow cavity under pressure, forming an interdigitated structure. If the interdigital PMMA gets in touch with the endplate, it can support the endplate to bear the load. However, in a fractured vertebral body with IVC, the balloon easily expands in the IVC area without compressing the adjacent bone. PMMA only fills the space formed by the balloon, and does not form an interdigitated pattern. Therefore, the endplate is only pushed by PMMA, and under the effect of stress shielding, the augmented vertebrae are prone to recollapse.\u003c/p\u003e\u003cp\u003eIn this study, higher RR and greater RA were the risk factors for augmented vertebrae recollapse. Niu et al.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e reported that vertebral height recovery and LKA correction significantly correlated with recompression (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and multiple binary logistic regression analysis demonstrated that the degree of VHR (OR\u0026thinsp;=\u0026thinsp;1.260; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) positively correlated with the recollapse of augmented vertebrae. Wang et al.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e showed that higher vertebral height recovery after PKP was more likely to lead to recollapse. Our results are consistent with previous research.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e The reasons for this result may be that higher RR and greater RA can lead to the increased paravertebral soft tissue tension, thereby resulting in more instability of the fracture segments or the increased mechanical load on the augmented vertebrae. In addition, Heo et al.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e suggested that in the augmented vertebrae, especially those with solid block cement distribution or preoperative IVC, excessive vertebral height restoration might promote osteonecrosis. However, there was no unified conclusion on the optimal reduction rate of vertebral height and reduction angle, which requires further research.\u003c/p\u003e\u003cp\u003eIn PVP, PMMA fills the cancellous bone of the fractured vertebra in an interdigitated manner. The distribution pattern of the cement is mainly divided into two modes, namely solid and trabecular. However, in PKP, PMMA is composed of one or two solid masses. Thus, in this study, we divided the cement distribution pattern into the separated group and confluent group. Previous studies have mainly reported the relationship between the distribution pattern of cement and pain residue after PKP.\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e He et al.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e showed that the pain relief effect was better in the confluent group than in the separated group. Li et al.\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e demonstrated that the quality of life of the separated group was significantly worse than that of the confluent cement distribution group. However, to date, no relevant research has mentioned the relationship between the distribution of separated and confluent cement and augmented vertebrae recollapse. In this study, we found that the separation distribution rate of recollapse group was higher than that of the maintaining group, and multivariate logistic regression analysis revealed that the distribution pattern of separated cement was an independent risk factor for the recollapse of augmented vertebrae.\u003c/p\u003e\u003cp\u003eRelevant studies have confirmed that back muscles are important for spine stability.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e However, the relationship between CSA and pFIA of paraspinal muscles and augmented vertebrae recollapse has rarely been mentioned in prior research. In this study, we found that larger pFIA of multifidus was an independent risk factor for the augmented vertebrae recollapse. Larger CSA of multifidus was identified as a protective factor for the augmented vertebrae recollapse. The reason may be that strong paravertebral muscles can reduce the stress between vertebrae, intervertebral disc, and facet joints, playing an irreplaceable role under higher load. In addition, there was a correlation between paraspinal muscle atrophy and muscle fatty infiltration with spinal and pelvic parameters, and the spine and muscles can interact to maintain sagittal balance in the human body.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e Patients with paraspinal muscle atrophy and fat infiltration may lead to bending and further sagittal imbalance of the spine, which can increase weight load and increase the risk of re collapse of the fractured vertebral body after surgery. Previous studies have shown that strengthening back muscle movement after surgery can improve body function, reduce pain, promote spinal height recovery, and maintain bone density.\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e Therefore, it was also crucial to evaluate muscle quality and strengthen exercises for the lower back muscles.\u003c/p\u003e\u003cp\u003eThe current research has some limitations. First, because the number of patients in the two groups were relatively small and the samples were from the same institution, the study results are not generalizable. Second, the CSA and FIA of the multifidus were evaluated on MRI. Therefore, a blind assessment was conducted by three experienced specialists to minimize bias. Third, there is no gold standard to evaluate the recollapse of augmented vertebrae. Wang et al.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e defined the augmented vertebrae recollapse as the reduction in the central vertebral body height by more than 2 mm in the last follow-up. Kim et al.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e defined the augmented vertebrae recollapse as the height of the postoperative anterior body greater than the final anterior body height by more than 1.0 mm. Niu et al.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e adopted the criterion of 4-mm reduced height of the vertebral body. In addition, ROC curve needs to determine the \"diagnostic authenticity\" of the study case. Due to the lack of the gold standard for vertebral collapse, the results will also deviate.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn conclusion, during follow-up, the augmented vertebrae height after PKP was usually partially offset by recollapse. Preoperative IVC, separated cement distribution, higher RR, greater RA, and larger pFIA of the multifidus were identified as the independent risk factors for the augmented vertebrae recollapse. Larger CSA of the multifidus was identified as the protective factor for the augmented vertebrae recollapse.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBody mass index\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCT\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eComputed tomography\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMagnetic resonance\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eOVCF\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eOsteoporotic vertebral compression fracture\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ePKP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePercutaneous kyphoplasty\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ePMMA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePolymethyl methacrylate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eVAS\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eVisual Analog Scale\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eVHR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eVertebral height ratio\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEthics approval and consent to participate\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study protocol was reviewed and approved by the Ethics Committee of the The First People\u0026apos;s Hospital of Jiashan County, Zhejiang Province. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eConsent for publication\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\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 generated during and analyzed during the current study are not publicly available due to privacy and ethical concerns but are available from the corresponding author on reasonable request.\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\u003eFunding\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work has no funding support.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAuthors\u0026apos; contributions\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eM.D. conducted data analysis and wrote the initial draft. J.L. reviewed and revised the initial draft. J.Y. conducted data collection. Y.P. designed the ideas for the paper.All authors reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAcknowledgements\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial:number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eJohnell O, Kanis JA. An estimate of the worldwide prevalence and disability associated with osteoporotic fractures. Osteoporos Int. 2006;17(12):1726\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGarfin SR, Yuan HA, Reiley MA. New technologies in spine: kyphoplasty and vertebroplasty for the treatment of painful osteoporotic compression fractures. Spine (Phila Pa 1976). 2001;26(14):1511\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLau E, Ong K, Kurtz S, Schmier J, Edidin A. Mortality following the diagnosis of a vertebral compression fracture in the Medicare population. J Bone Joint Surg Am. 2008;90(7):1479\u0026ndash;86.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZethraeus N, Borgstr\u0026ouml;m F, Str\u0026ouml;m O, Kanis JA, J\u0026ouml;nsson B. Cost-effectiveness of the treatment and prevention of osteoporosis\u0026ndash;a review of the literature and a reference model. Osteoporos Int. 2007;18(1):9\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eStevenson M, Gomersall T, Lloyd Jones M, et al. Percutaneous vertebroplasty and percutaneous balloon kyphoplasty for the treatment of osteoporotic vertebral fractures: a systematic review and cost-effectiveness analysis. Health Technol Assess. 2014;18(17):1\u0026ndash;290.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShah LM, Jennings JW, Kirsch CFE, et al. ACR Appropriateness Criteria(\u0026reg;) Management of Vertebral Compression Fractures. J Am Coll Radiol. 2018;15(11s):S347\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKim DH, Vaccaro AR. Osteoporotic compression fractures of the spine; current options and considerations for treatment. Spine J. 2006;6(5):479\u0026ndash;87.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSuzuki N, Ogikubo O, Hansson T. The course of the acute vertebral body fragility fracture: its effect on pain, disability and quality of life during 12 months. Eur Spine J. 2008;17(10):1380\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYang H, Liu H, Wang S, Wu K, Meng B, Liu T. Review of Percutaneous Kyphoplasty in China. Spine (Phila Pa 1976). 2016;41(Suppl 19):B52\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKasperk C, Hillmeier J, N\u0026ouml;ldge G, et al. Treatment of painful vertebral fractures by kyphoplasty in patients with primary osteoporosis: a prospective nonrandomized controlled study. J Bone Min Res. 2005;20(4):604\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLandham PR, Baker-Rand HL, Gilbert SJ, et al. Is kyphoplasty better than vertebroplasty at restoring form and function after severe vertebral wedge fractures? Spine J. 2015;15(4):721\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNiu J, Zhou H, Meng Q, Shi J, Meng B, Yang H. Factors affecting recompression of augmented vertebrae after successful percutaneous balloon kyphoplasty: a retrospective analysis. Acta Radiol. 2015;56(11):1380\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOh HS, Kim TW, Kim HG, Park KH. Gradual Height Decrease of Augmented Vertebrae after Vertebroplasty at the Thoracolumbar Junction. Korean J Neurotrauma. 2016;12(1):18\u0026ndash;21.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKim YY, Rhyu KW. Recompression of vertebral body after balloon kyphoplasty for osteoporotic vertebral compression fracture. Eur Spine J. 2010;19(11):1907\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLin WC, Lee YC, Lee CH, et al. Refractures in cemented vertebrae after percutaneous vertebroplasty: a retrospective analysis. Eur Spine J. 2008;17(4):592\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLin WC, Lu CH, Chen HL, et al. The impact of preoperative magnetic resonance images on outcome of cemented vertebrae. Eur Spine J. 2010;19(11):1899\u0026ndash;906.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee JC, Cha JG, Kim Y, Kim YI, Shin BJ. Quantitative analysis of back muscle degeneration in the patients with the degenerative lumbar flat back using a digital image analysis: comparison with the normal controls. Spine (Phila Pa 1976). 2008;33(3):318\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRanson CA, Burnett AF, Kerslake R, Batt ME, O'Sullivan PB. An investigation into the use of MR imaging to determine the functional cross sectional area of lumbar paraspinal muscles. Eur Spine J. 2006;15(6):764\u0026ndash;73.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang C, Zhang X, Liu J, Shan Z, Li S, Zhao F. Percutaneous kyphoplasty: Risk Factors for Recollapse of Cemented Vertebrae. World Neurosurg. 2019;130:e307\u0026ndash;15.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYu W, Xu W, Jiang X, Liang D, Jian W. Risk Factors for Recollapse of the Augmented Vertebrae After Percutaneous Vertebral Augmentation: A Systematic Review and Meta-Analysis. World Neurosurg. 2018;111:119\u0026ndash;29.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHe D, Lou C, Yu W, et al. Cement Distribution Patterns Are Associated with Recompression in Cemented Vertebrae After Percutaneous Vertebroplasty: A Retrospective Study. World Neurosurg. 2018;120:e1\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHasegawa K, Homma T, Uchiyama S, Takahashi H. Vertebral pseudarthrosis in the osteoporotic spine. Spine (Phila Pa 1976). 1998;23(20):2201\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIto Y, Hasegawa Y, Toda K, Nakahara S. Pathogenesis and diagnosis of delayed vertebral collapse resulting from osteoporotic spinal fracture. Spine J. 2002;2(2):101\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBaur A, St\u0026auml;bler A, Arbogast S, Duerr HR, Bartl R, Reiser M. Acute osteoporotic and neoplastic vertebral compression fractures: fluid sign at MR imaging. Radiology. 2002;225(3):730\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHeo DH, Chin DK, Yoon YS, Kuh SU. Recollapse of previous vertebral compression fracture after percutaneous vertebroplasty. Osteoporos Int. 2009;20(3):473\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi Y, Yue J, Huang M, et al. Risk factors for postoperative residual back pain after percutaneous kyphoplasty for osteoporotic vertebral compression fractures. Eur Spine J. 2020;29(10):2568\u0026ndash;75.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHe S, Zhang Y, Lv N, et al. The effect of bone cement distribution on clinical efficacy after percutaneous kyphoplasty for osteoporotic vertebral compression fractures. Med (Baltim). 2019;98(50):e18217.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGoel VK, Kong W, Han JS, Weinstein JN, Gilbertson LG. A combined finite element and optimization investigation of lumbar spine mechanics with and without muscles. Spine (Phila Pa 1976). 1993;18(11):1531\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXia W, Fu H, Zhu Z, et al. Association between back muscle degeneration and spinal-pelvic parameters in patients with degenerative spinal kyphosis. BMC Musculoskelet Disord. 2019;20(1):454.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDeng D, Lian Z, Cui W, Liang H, Xiao L, Yao G. Function of low back muscle exercise: Preventive effect of refracture analysis of postoperative vertebral fractures. Orthopade. 2019;48(4):337\u0026ndash;42.\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":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Percutaneous kyphoplasty, Vertebrae recollapse, Paraspinal muscle","lastPublishedDoi":"10.21203/rs.3.rs-6983662/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6983662/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives:\u003c/strong\u003e The purpose of this study was to analyze the risk factors for recollapse of augmented vertebrae after percutaneous kyphoplasty (PKP).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e Patients who had been treated with bilateral PKP and met the inclusion criteria were retrospectively reviewed. We assessed the following potential risk factors for augmented vertebrae recollapse: age, gender, weight, height, body mass index (BMI), preoperative T-score in bone mineral density (BMD), fracture spine level, follow-up duration, reduction rate (RR), reduction angle (RA), cement volume, preoperative intravertebral cleft (IVC), cement contact with endplates, cement distribution, and the cross-sectional area (CSA) and percent fatty infiltration area (pFIA) of the multifidus. Univariate and multivariate regression analyses were progressively performed to identify the risk factors for augmented vertebrae recollapse.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e A total of 112 patients were enrolled in the study. There were 27 (24.1%) patients in the recollapse group. Multivariate regression analysis identified preoperative IVC, separated cement distribution, higher RR, greater RA, and larger pFIA of the multifidus as the risk factors for the augmented vertebrae recollapse.Larger CSA of the multifidus was a protective factor for vertebral body recompression. Receiver operating characteristic (ROC) curve analysis showed that the areas under the ROC curve of higher RR, greater RA, larger pFIA, and larger CSA were 0.710, 0.649, 0.714,and 0.754, respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e Preoperative IVC, separated cement distribution, higher RR, greater RA, and larger FIA of the multifidus are independent risk factors for the augmented vertebrae recollapse. Larger CSA of the multifidus is a protective factor for the augmented vertebrae recollapse.\u003c/p\u003e","manuscriptTitle":"Risk factors for augmented vertebrae recollapse after percutaneous kyphoplasty for osteoporotic vertebral compression fractures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-14 10:22:38","doi":"10.21203/rs.3.rs-6983662/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-19T15:05:43+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-07T10:04:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-21T15:32:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"278573577238576905167899144997604096682","date":"2025-08-05T14:35:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"142487694098080333956350316588802467265","date":"2025-07-31T00:03:10+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-29T13:15:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"228802654626502283175168893203259881335","date":"2025-07-09T14:25:15+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-08T14:53:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-07T06:55:20+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-05T07:59:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2025-07-05T07:56:41+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ad0345a5-92c9-4502-a80d-88db1491e4ae","owner":[],"postedDate":"July 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2025-12-19T15:09:45+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-14 10:22:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6983662","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6983662","identity":"rs-6983662","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}