Yu-Hsien Kao

Impact of cement leakage into disks on the development of adjacent vertebral compression fractures.

Study Design A retrospective study assessing new adjacent vertebral compression fracture (VCF) after percutaneous vertebroplasty (PV). Objective To evaluate the relationship between cement leakage into the disk during initial PV and development of subsequent new adjacent VCF. Summary of Background Data Cement leakage outside the vertebral body during PV has been reported and usually responds to conservative treatment. Sometimes bone cement may leak into the intervertebral disk and result in painful new adjacent VCF that usually requires another PV for pain relief. Methods From January 2002 to December 2002, a total of 106 consecutive patients underwent PVs for osteoporotic VCFs. The risk of new fractures of adjacent vertebral bodies, the amount of cement injection, and the duration of development of new adjacent fractures in relation to cement leakage into the disk were retrospectively assessed and statistically compared. Results New adjacent VCFs occurred in 20 (18.9%) of 106 patients at 22 adjacent vertebral bodies after PVs during at least 24 months of follow-up. The difference in number of new adjacent fractures between both patients and vertebral bodies with cement leakage and those without leakage into the disk were statistically significant (P<0.001 and P<0.001). Amounts of cement injected and duration to development of new adjacent fractures differed between patients with or without cement leakage (P<0.001 and P=0.005, respectively). Conclusions PV is a simple and effective, but not risk-free or complication-free procedure for the treatment of osteoporotic VCF. Patients undergoing PV should be informed of the possibility of new adjacent fractures and the higher risk if cement leaks into the disk.

Clinical evaluation of repeat percutaneous vertebroplasty for symptomatic cemented vertebrae.

Background: Percutaneous vertebroplasty (PV) with polymethylmethacrylate is widely used to treat osteoporotic vertebral compression fracture and satisfactory clinical outcomes have been reported in the literature. However, recurrent or persistent back pain after PV is not uncommon. Sometimes, the pain may result from pathogenesis within the previously treated vertebra. In this study, we evaluated the efficacy and safety of repeat PV for treating patients with recurrent back pain caused by the previously cemented vertebrae. Methods: We retrospectively reviewed the medical records of 18 patients who underwent repeat PV to treat symptomatic cemented vertebrae. Patients were categorized into 3 groups based on clinical presentation and imaging studies: those with refracture (RF), residual vacuum (RV), and osteonecrosis (ON) along the bone-cement interface. A bipedicle approach was used for repeat PV in all patients. The visual analogue scale (VAS) and modified Brodsky criteria were used to evaluate clinical outcomes before and after surgery. The Kruskal-Wallis test, Wilcoxon signed-rank test, and Spearman correlation analyses were used to analyze patient surgical prognosis and radiologic findings. Results: Nine patients were diagnosed with RF, 5 with RV, and 4 with ON. The average VAS score was 77.1 (range, 62–90) before repeat PV (80.1, 72.4, and 76.3 for the RF, RV, and ON groups, respectively) and 34.4 (range, 25–45) after repeat PV treatment (33.1, 36.8, and 34.3 for the RF, RV, and ON groups, respectively). The VAS score significantly decreased in all 3 groups. The vertebral body height was significantly restored by a mean of 13.9% across all groups (17.8%, 12.7%, and 6.8% in the RF, RV, and ON groups, respectively). Fifteen patients recovered from vertebral compression fracture and regained their preinjury activities of daily living. No surgery-related complications occurred except asymptomatic cement leakage in 5 patients. Conclusions: The results of this research demonstrate that repeat PV may be an effective method for relieving recurrent or persistent pain in patients with symptomatic cemented vertebrae, allowing them to regain functional activity.

Clinical evaluation of percutaneous vertebroplasty for symptomatic adjacent vertebral compression fracture.

Study Design: A retrospective study. Objective: To evaluate the efficacy and safety of percutaneous vertebroplasty (PV) for treating patients with symptomatic osteoporotic vertebral compression fractures (VCFs) adjacent to lumbar instrumented circumferential fusion. Summary of Background Data: Few studies have investigated adjacent VCFs and their management after spinal fusion surgery for degenerative lumbar disease. Patients and Methods: From January 2005 to July 2011, a total of 23 patients with lumbar instrumented circumferential fusion suffered from adjacent symptomatic osteoporotic VCFs. All of these patients received PV using polymethylmethacrylate bone cement augmentation in our institute. Radiography and magnetic resonance imaging were used for imaging studies. The visual analog scale and modified Brodsky criteria were used to compare clinical outcomes before and after surgery. The minimum follow-up period was 18 months (range, 18–45 mo). Results: One level PV was performed in 18 patients and 2 levels were performed in 5 patients. The patients’ visual analog scale scores improved by an average of 54.3 points after the procedure. Twenty patients returned to their preinjury activities of daily living. Lumbar lordosis was increased from 28.9 degrees before PV to 36.2 degrees after PV. The average restoration of the fractured vertebral body height was 14.0%. No surgery-related complications occurred except asymptomatic cement leakage in 4 patients. Conclusions: PV is a minimally invasive and effective procedure to treat patients with symptomatic osteoporotic VCFs adjacent to lumbar instrumented circumferential fusion.

Bone mineral density in patients with symptomatic vertebral compression fractures after instrumented spinal fusion: A retrospective analysis

Background: Few studies have been published concerning about the osteoporotic symptomatic vertebral compression fractures (VCFs) following instrumented spinal fusion for degenerative spinal disease. Purpose: The purpose of this study was to evaluate the incidence of symptomatic VCFs and the differences in the timing of occurrence and bone mineral density (BMD) between patients with adjacent and remote VCFs after instrumented spinal fusion. Methods: We performed a retrospective analysis of 1,936 patients who received posterior instrumentation for degenerative spinal disease at our institution and were followed-up for at least 3 years. Dual-energy X-ray absorptiometry surveys were arranged, and symptomatic subsequent VCFs were identified during regular follow-up. Eligible patients were divided into two groups (adjacent or remote to instrumented spinal fusion, based on the location of their VCFs. The Wilcoxon signed-rank test or chi-square test was used to assess between-group differences. Linear regression analysis was used to examine the relationship between the timing of the occurrence of VCFs and BMD (T-score). Results: The incidence of symptomatic VCFs following instrumented lumbar spine fusion was 2.37% (46/1,936), which accounted for 20.53% (46/224) of patients with VCFs. Linear regression analysis revealed a positive trend between the timing of the occurrence of symptomatic VCFs and values of BMD (T-score). The mean time to develop adjacent VCFs was 6.8 months, while that to develop remote VCFs was 13.7 months (p ＜ 0.05). Conclusion: Symptomatic adjacent VCFs occurred much earlier than remote VCFs. Device-related osteoporosis may be one of risks in subsequent VCFs, which highlight the importance of osteoporosis medication.

Impact of Instrumented Spinal Fusion on the Development of Vertebral Compression Fracture

AbstractInstrumented spinal fusion has become one of the most common surgeries for patients with various spinal disorders. Only few studies have reported subsequent vertebral compression fractures (VCFs) after instrumented spinal fusion. The purpose of this study was to evaluate the risk of new VCFs in patients undergoing instrumented spinal fusion.We obtained claims data from the National Health Insurance Research Database of Taiwan and retrospectively reviewed 6949 patients with instrumented spinal fusion as the spinal fusion cohort. Control subjects were individually matched at a ratio of 10:1 with those of the spinal fusion cohort according to age, sex, and the index day. Comorbidities were classified as those existing before the index day, and these included diabetes mellitus, hypertension, osteoporosis, and cerebrovascular accident. The end of the follow-up period for the analyses was marked on the day new VCFs developed, enrolment in the National Health Insurance was terminated, on the day of death, or until the end of 2012. We used the Cox proportion hazards model to analyze the hazard ratio (HR) for developing new VCFs.Patients with instrumented spinal fusion were significantly more likely to develop new VCFs (1.87% vs .25%, HR: 8.56; P < 0.001). Female, elderly, and osteoporotic patients had a high incidence of new VCFs after spinal fusion. The HR for developing new VCFs after instrumented spinal fusion was higher in patients younger than 65 years than in those 65 years or older (HR: 10.61 vs 8.09). Male patients with instrumented spinal fusion also had a higher HR of developing new VCFs than female patients (men, HR: 26.42; women, HR: 7.53).In our retrospective cohort study, patients who had undergone instrumented spinal fusion surgery exhibited an increased risk of developing new VCFs. Particularly, the HR increased in young (age <65 years) and male patients.

Posterior Decompression and Spinopelvic Fixation Using Commercial Pedicle Screw Instead of Iliac Screw for Metastatic Sacral Tumor

Background: Mechanical stabilization of metastatic pathological fracture of the sacrum is technically challenging. There is often inadequate purchase in the sacrum, and instrumentation has to be achieved between the lumbar vertebrae and the ilium. In addition, commercial iliac screws are usually unavailable at most institutes in Taiwan. The purpose of this study is to evaluate the feasibility and efficacy of the original pedicle screw instead of the iliac screw for spinopelvic fixation in patients with metastatic sacral tumor. Methods: From January 2006 to December 2012, we performed posterior decompression and supplemental instrumentation to treat 15 patients with metastatic sacral tumor at our institutes. The original pedicle screw, with 65 mm in length and 7 mm in diameter, was used instead of the iliac screw for spinopelvic fixation. The visual analog score (VAS), modified Brodskys criteria, Frankel scale, and Oswestry Disability Index (ODI) were recorded before surgery, before discharge, and 6 months after surgery to evaluate the clinical outcomes. Results: The average VAS was 8.1 (range, 7 to 9) before surgery; it significantly decreased to 3.3 (range, 3 to 4) after surgery (p ＜ 0.001), and continued to decrease to 1.9 (range, 1 to 3) at 6 months after surgery (p=0.001). The average ODI measured 82.9% (range, 76% to 92%) before surgery, significantly decreased to 27.2% (range, 20% to 36%) after surgery (p=0.001), and continued to decrease to 20.8% (range, 16% to 28%) 6 months after surgery (p=0.001). All patients achieved a good or excellent outcome based on modified Brodskys criteria, and the improvement was significant after surgery (p ＜ 0.001). No patient experienced surgery-related complications or neurologic deterioration. Three patients expired due to tumor progression at 10 months, 12 months, and 19 months after surgery. Conclusions: Spinopelvic fixation using commercial pedicle screw and associated neurologic decompression can provide good clinical outcomes and a low complication rate for patients with metastatic sacral tumor.