The incidence and risk factors for extensive epidural cement leakage in cement-augmented pedicle screw fixation: a multicenter retrospective study.

INTRODUCTION: In cement-augmented pedicle screw fixation (CAPSF), epidural cement leakage (CL) is a frequently reported complication with the potential for neural injury, especially when it is extensive. To date, there has been no reports discussing basivertebral foramen morphology and pedicle screw placement, which is critical in the analysis of the risk of extensive epidural CL. Thus, this study aimed to identify the incidence and risk factors for extensive epidural CL in osteoporotic patients with CAPSF. MATERIALS AND METHODS: 371 osteoporotic patients using 1898 cement-augmented screws were included. Preoperative computed tomography (CT) was utilized to characterize basivertebral foramen morphology. Following CAPSF, the severity of epidural CL, the implantation position of pedicle screw and cement extension within the vertebral body were determined by postoperative CT. In this study, significant risk factors for extensive epidural CL were identified through logistic regression analysis. RESULTS: There were 19 patients (5.1%) and 32 screws (1.7%) with extensive epidural CL. Nine patients (involving 19 screws) had neurological symptoms. The independent risk factors for patients with extensive epidural CL were decreased BMD and increased number of augmented screws. Significant predictors for extensive epidural CL were a magistral type of basivertebral foramen, more volume of cement injected, solid screw, a shallower screw implantation, and the smaller distance between the tip of the screw and the midline of vertebral body. CONCLUSION: Extensive epidural CL risk was significant in CAPSF when a magistral basivertebral foramen was present; solid screws and more volume of cement were used; and screw tip was implanted shallower or closer to the midline.

Prediction of subsequent vertebral compression fractures after thoracolumbar kyphoplasty: a multicenter retrospective analysis.

OBJECTIVE: Second fractures at the cemented vertebrae (SFCV) are often seen after percutaneous kyphoplasty, especially at the thoracolumbar junction. Our study aimed to develop and validate a preoperative clinical prediction model for predicting SFCV. METHODS: A cohort of 224 patients with single-level thoracolumbar osteoporotic vertebral fractures (T11-L2) from 3 medical centers was analyzed between January 2017 and June 2020 to derive a preoperative clinical prediction model for SFCV. Backward-stepwise selection was used to select preoperative predictors. We assigned a score to each selected variable and developed the SFCV scoring system. Internal validation and calibration were conducted for the SFCV score. RESULTS: Among the 224 patients included, 58 had postoperative SFCV (25.9%). The following preoperative measures on multivariable analysis were summarized in the 5-point SFCV score: bone mineral density (≤-3.05), serum 25-hydroxy vitamin D3 (≤17.55 ng/mL), standardized signal intensity of fractured vertebra on T1-weighted images (≤59.52%), C7-S1 sagittal vertical axis (≥3.25 cm), and intravertebral cleft. Internal validation showed a corrected area under the curve of 0.794. A cutoff of ≤1 point was chosen to classify a low risk of SFCV, for which only 6 of 100 patients (6%) had SFCV. A cutoff of ≥4 points was chosen to classify a high risk of SFCV, for which 28 of 41 (68.3%) had SFCV. CONCLUSION: The SFCV score was found to be a simple preoperative method for identification of patients at low and high risk of postoperative SFCV. This model could be applied to individual patients and aid in the decision-making before percutaneous kyphoplasty.

Lower ratio of adjacent to injured vertebral bone quality scores can predict augmented vertebrae recompression following percutaneous kyphoplasty for osteoporotic vertebral fractures with intravertebral clefts.

BACKGROUND: Despite the favorable clinical outcome of percutaneous kyphoplasty (PKP) in symptomatic osteoporotic vertebral fractures (OVFs) patients with intravertebral clefts (IVCs), previous studies have demonstrated a high incidence of augmented vertebrae recompression (AVR). We aim to evaluate the usefulness of the adjacent and injured vertebral bone quality scores (VBQS) based on T1-weighted MRI images in AVR after PKP for OVFs with IVCs. METHODS: Patients who underwent PKP for single OVFs with IVCs between January 2014 and September 2020 were reviewed and met the inclusion criteria. The follow-up period was at least 2 years. Relevant data affecting AVR were collected. Pearson and Spearman correlation coefficients were used to calculate the correlation between the injured and adjacent VBQS and BMD T-score. We determined independent risk factors and critical values using binary logistic regression analysis and receiver operating characteristic curves (ROC). RESULTS: A total of 165 patients were included. Recompression group was found in 42 (25.5%) patients. The independent risk factors for AVR were lumbar BMD T-score (OR = 2.53, p = 0.003), the adjacent VBQS (OR = 0.79, p = 0.016), the injured VBQS (OR = 1.27, p = 0.048), the ratio of adjacent to injured VBQS (OR = 0.32, p < 0.001), and cement distribution pattern. Among these independent significant risk factors, the prediction accuracy of the ratio of adjacent to injured VBQS was the highest (Cutoff = 1.41, AUC = 0.753). Additionally, adjacent and injured VBQS were negatively correlated with lumbar BMD T-scores. CONCLUSION: For the patients after PKP treatment for OVFs with IVCs, the ratio of adjacent to injured VBQS had the best prediction accuracy in predicting recompression and when the ratio of adjacent to injured VBQS was <1.41, the augmented vertebrae were more likely to have recompression in the future.

Biomechanical effects of cement distribution in the fractured area on osteoporotic vertebral compression fractures: a three-dimensional finite element analysis.

BACKGROUND: According to some clinical studies, insufficient cement distribution (ID) in the fractured area and asymmetrical cement distribution around the fractured area were thought to be the reasons for unrelieved pain and recollapse after percutaneous vertebral augmentation (PVA) in the treatment of symptomatic osteoporotic vertebral compression fractures. METHODS: Finite element methods were used to investigate the biomechanical variance among three patterns of cement distribution (ID and sufficient cement distribution in the fractured area and asymmetrical cement distribution around the fractured area including upward [BU] and downward [BD] cement distribution). RESULTS: Compared with fractured vertebra before PVA, distribution of von Mises stress in the cancellous bone was transferred to be concentrated at the cancellous bone surrounding cement after PVA, whereas it was not changed in the cortical bone. Compared with sufficient cement distribution group, maximum von Mises stress in the cancellous bone and cortical bone and maximum displacement of augmented vertebra increased significantly in the ID group, whereas asymmetrical cement distribution around the fractured area in BU and BD groups mainly increased maximum von Mises stress in the cancellous bone significantly. Similar results could be seen in all loading conditions. CONCLUSIONS: ID in the fractured area may lead to unrelieved pain after PVA in the treatment of symptomatic osteoporotic vertebral compression fractures as maximum displacement of augmented vertebral body increased significantly. Both ID in the fractured area and asymmetrical cement distribution around the fractured area are more likely to induce recollapse of augmented vertebra because they increased maximum von Mises stress in the cancellous bone and cortical bone of augmented vertebra significantly.

Anatomic distribution of basivertebral foramen with a magistral form in vertebral bodies of T10~L5 and its clinical significance for extensive epidural cement leakage in cement-augmented pedicle screw fixation: a multicenter case-control study.

BACKGROUND: There are no reports discussing anatomic distribution of basivertebral foramen (BVF) in the osteoporotic vertebral body, which is critical in the analysis of the risk of epidural cement leakage (ECL) after cement-augmented pedicle screw fixation (CAPSF). METHODS: 371 osteoporotic patients using 1898 cement-augmented screws were included. Preoperative computed tomography (CT) was used to determine the frequency, width, height, and depth of magistral BVF in T10~L5. Additionally, we measured the distance between BVF and the left/right borders of vertebral body as well as the distance between BVF and upper/lower endplates. Following CAPSF, the severity of ECL and the position of pedicle screws were determined by postoperative CT. Finally, significant risk factors for extensive ECL were identified through binary logistic regression analysis. RESULTS: Of 2968 vertebral bodies ranging from T10 to L5, 801 (42.2%) had a magistral BVF. From T10 to L5, the frequency of magistral BVF appeared to gradually increase. The magistral BVF was much closer to the upper endplate and the depth accounted for about a quarter of anteroposterior diameter of vertebral body. Overall, there were 19 patients (5.1%) and 32 screws (1.7%) with extensive ECL, nine of whom had neurological symptoms. The independent risk factors for extensive ECL were the magistral BVF (OR = 8.62, P < 0.001), more volume of cement injected (OR = 1.57, P = 0.031), reduced distance from screw tip to vertebral midline (OR = 0.76, P = 0.003) and vertebral posterior wall (OR = 0.77, P < 0.001) respectively. CONCLUSION: When planning a CAPSF procedure, it is important to consider anatomical distribution of BVF and improve screw implantation methods.

Establishment and Validation of Nomograms and Web Calculators for Different Cement Leakage Risk Types in Pedicle Screw Augmentation for Degenerative Lumbar Stenosis in Osteoporotic Vertebrae.

BACKGROUND: The use of cement in pedicle screw augmentation (PSA) enhances the pullout force of pedicle screws in vertebrae affected by osteoporosis. Risks involved in the use of cement for PSA include nerve injury and vascular damage caused by cement leakage. METHODS: This study included all patients who received PSA for degenerative lumbar stenosis in osteoporotic vertebrae from January 2014 to May 2022. Postoperative computed tomography was used to assess cement leakage. Correlation analysis and logistic regression analyses were used to establish the associated clinical or radiological factors, which were then used to construct nomograms and web calculators. RESULTS: The study comprised 181 patients including 886 screws inserted into 443 vertebrae. Perivertebral cement leakage was significantly associated with female sex, decreased bone mineral density, solid screws, and scattered cement distribution. Cement leakage through segmental veins (type S, 72.1%), leakage through basivertebral veins (type B, 23.9%), and instrument-related leakage (type I, 13.9%) accounted for most cement leakage. Patients with lower bone mineral density and scattered cement distribution were more likely to experience type S or type B leakage. Our analysis data showed that cement augmentation with cannulated and fenestrated screws tended toward concentrated cement distribution. Creation and verification of each nomogram additionally showcased the prognostic capability and medical significance of the corresponding model. CONCLUSIONS: Nomograms and web-based calculators can accurately forecast the probability of cement leakage. PSA should be routinely performed using cannulated and fenestrated screws, along with a moderate amount of high-viscosity cement, with continuous monitoring using fluoroscopy.

Establishment of a novel risk prediction model for recompression of augmented vertebrae at the thoracolumbar junction and modified puncture technique for prevention: a multicenter retrospective study.

OBJECTIVE: Recompression of augmented vertebrae (RCAV) is often seen after percutaneous kyphoplasty (PKP), especially at the thoracolumbar junction. The authors aimed to develop and validate a risk prediction model (nomogram) for RCAV and to evaluate the efficacy of a modified puncture technique for RCAV prevention after PKP for thoracolumbar osteoporotic vertebral fractures (OVFs). METHODS: Patients who underwent PKP for single thoracolumbar OVFs (T10-L2) between January 2016 and October 2020 were reviewed and followed up for at least 2 years. All patients were randomly divided into a training group (70%) and a validation group (30%). Relevant potential data affecting recompression were collected. Predictors were screened by using binary logistic regression analysis to construct the nomogram. Calibration and receiver operating characteristic curves were used to evaluate the consistency of the prediction models. Finally, the efficacy of the modified puncture technique for prevention of RCAV in OVF patients with a preoperative intravertebral cleft (IVC) was further demonstrated through binary logistic regression analysis. RESULTS: Overall, 394 patients were included and 116 of them (29.4%) sustained RCAV. The independent risk factors included decreased bone mineral density, lower level of serum 25-hydroxy vitamin D3, larger C7-S1 sagittal vertical axis (SVA), preoperative IVC, and solid-lump cement distribution. The area under the curve (AUC) of the prediction model was 0.824 in the training group and 0.875 in the validation group patients. The calibration curve indicated the predictive power of this nomogram, with the preoperative IVC having the highest prediction accuracy (AUC 0.705). The modified puncture technique significantly reduced the incidence of RCAV by enhancing bone cement distribution into a sufficiently diffused distribution in OVF patients with preoperative IVC. CONCLUSIONS: The nomogram prediction model had satisfactory accuracy and clinical utility for identification of patients at low and high risk of postoperative RCAV. Patients at high risk of postoperative RCAV might benefit from the target puncture technique and vitamin D supplementation as well as effective antiosteoporotic therapies.

The Potential Impact of Basivertebral Foramen Morphology and Pedicle Screw Placement on Epidural Cement Leakage With Cement-Augmented Fenestrated Pedicle Screw Fixation: A Multicenter Retrospective Study of 282 Patients and 1404 Augmented Screws.

BACKGROUND: Epidural cement leakage (CL) is a common complication in cement-augmented fenestrated pedicle screw fixation (CAFPSF) with the potential for neural injury. However, there are no reports discussing basivertebral vein morphology and pedicle screw placement, which are critical in the analysis of the risk of epidural CL after CAFPSF. OBJECTIVE: To identify the incidence and risk factors of epidural CL in osteoporotic patients during CAFPSF. METHODS: Two hundred and eighty-two osteoporotic patients using 1404 cement-augmented fenestrated screws were included. Preoperative computed tomography (CT) was used to characterize the morphology of posterior cortical basivertebral foramen. After CAFPSF, the severity of epidural CL, the implantation position of the screw tip, and cement extension within the vertebral body were determined by postoperative CT scans. In this study, significant risk factors for epidural CL were identified through logistic regression analysis. RESULTS: In total, 28 patients (18.8%) and 108 screws (7.7%) had epidural CL and 7 patients (13 screws) experienced neurological symptoms. Although local epidural CL was generally not clinically significant, extensive epidural leakage posed a higher risk of neurological symptoms. Significant predictors for extensive epidural CL were a magistral type of basivertebral foramen and the smaller distance between the tip of the screw and the posterior wall of the vertebral body. CONCLUSION: In osteoporotic patients receiving CAFPSF, epidural CL is relatively common. The morphology of basivertebral foramen should be taken into account when planning a CAFPSF procedure. It is important to try and achieve a deeper screw implantation, especially when a magistral type of basivertebral foramen is present.

[Risk factors of hidden blood loss in percutaneous vertebral augmentation].

OBJECTIVE: To explore the risk factors of hidden blood loss in osteoporosis vertebral compression fractures during percutaneous vertebral augmentation. METHODS: From October 2018 to December 2019, 360 patients with osteoporosis vertebral compression fractures who received percutaneous vertebral augmentation were enrolled in this study. The factors analyzed included gender, age, surgical methods, disease course, height, weight, the operative segment, bone mineral density, amount of bone cement, operative time, percentage of height loss, percentage of vertebral height restoration, cement leakage, blood clotting function, preoperative and postoperative hemoglobin and hematocrit and other internal diseases. Total blood loss was calculated by Gross's formula, influential factors of the hidden blood loss were further analyzed by t-test, multivariate linear regression and one-way ANOVA analysis. RESULTS: Surgical methods, the operative segment, disease course, cement leakage, preoperative hemoglobin, cement leakage via the basivertebral and segmental vein were significantly correlated with hidden blood loss(P<0.05). CONCLUSION: Patients with percutaneous kyphoplasty, two-level and multi-level surgery, the course of the disease beyond 6 weeks, cement leakage via the basivertebral and segmental vein, and lower preoperative hemoglobin had more perioperative hidden blood loss.

Comparison of Cement Leakage Rate and Severity After Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures Using Front-Opening Versus Side-Opening Cannulas.

The authors assessed the occurrence and severity of cement leakage (CL) following percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCFs) performed using front-opening cannulas (FOCs) vs side-opening cannulas (SOCs). This retrospective cohort study included 811 patients with single-level OVCFs who underwent PVP between March 2016 and September 2018. The 264 patients who met the inclusion criteria were divided into two groups according to whether the procedure was performed using a FOC (n=128) or a SOC (n=136). Visual analog scale score, Oswestry Disability Index, local kyphotic angle, vertebral height, amount of bone cement injected, and rate of CL were compared between the groups. Types of CL were classified according to postoperative computed tomography. The CL types were further classified according to severity (mild and severe). Visual analog scale score, Oswestry Disability Index, local kyphotic angle, and vertebral height were all significantly improved after surgery. The total incidence of CL was significantly higher for FOCs than for SOCs (P=.001). Similarly, the occurrence of the CL subtypes was significantly higher for FOCs than for SOCs (B type, P=.033; C type, P=.01; and S type, P=.015). Analysis of CL type severity revealed that the rates of severe D type (intradiskal leakage category of the C type) and severe S type were significantly lower for SOCs than for FOCs (P=.001), while the incidence of severe B type leaks was not significantly different between the groups (P=.443). Percutaneous vertebroplasty performed using SOCs decreases the incidence and severity of D type and S type CL compared with FOCs. Secondary classification of CL could help physicians better understand the severity of leakage and select a more appropriate surgical approach to reduce CL. [Orthopedics. 2021;44(3):134-140.].

Influence of bone cement distribution on outcomes following percutaneous vertebroplasty: a retrospective matched-cohort study.

OBJECTIVE: To evaluate the influence of insufficient bone cement distribution on outcomes following percutaneous vertebroplasty (PVP). METHODS: This retrospective matched-cohort study included patients 50-90 years of age who had undergone PVP for single level vertebral compression fractures (VCFs) from February 2015 to December 2018. Insufficient (Group A)/sufficient (Group B) distribution of bone cement in the fracture area was assessed from pre- and post-operative computed tomography (CT) images. Assessments were before, 3-days post-procedure, and at the last follow-up visit (≥12 months). RESULT: Of the 270 eligible patients, there were 54 matched pairs. On post-operative day 3 and at the last follow-up visit, significantly greater visual analogue scale (VAS) pain scores and Oswestry Disability Index (ODI) scores were obtained in Group B over Group A, while kyphotic angles (KAs) and vertebral height (VH) loss were significantly larger in Group A compared with Group B. Incidence of asymptomatic cement leakage and re-collapse of cemented vertebrae were also greater in Group A compared with Group B. CONCLUSIONS: Insufficient cement distribution may relate to less pain relief and result in progressive vertebral collapse and kyphotic deformity post-PVP.

Risk Factors for the Occurrence of Insufficient Cement Distribution in the Fractured Area after Percutaneous Vertebroplasty in Osteoporotic Vertebral Compression Fractures.

BACKGROUND: Insufficient cement distribution (ICD) in the fractured area has been advocated to be responsible for unsatisfied pain relief after percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCFs). However, little is known about risk factors for the occurrence of ICD. OBJECTIVE: The present study aimed to identify independent risk factors of the emergence of ICD. STUDY DESIGN: A retrospective cohort study. SETTING: Department of spinal surgery, an affiliated hospital of a medical university. METHODS: Patients who underwent PVP for single-level OVCF from January 2012 to September 2014 and met this study's inclusion criteria were retrospectively reviewed. Associations of ICD with co-variates (age, gender, bone mass density with a T-score, amount of injected cement, cement leakage, fracture level, fracture age, fracture severity grade, and location of the fractured area) and the influence of ICD on pain relief were analyzed. RESULTS: A total of 225 patients were included. ICD was found in 26 (11.6%) patients. Fractured area located in the superior portion of the index vertebra was significantly associated with occurrence of ICD. No further significant associations between the studied co-variates and emergence of ICD were seen in the adjusted analysis. In addition, patients with ICD had significantly higher immediate postoperative visual analog scale scores of back pain compared with those with sufficient cement distribution in the fractured area. LIMITATION: Location of the fractured area and cement distribution in the fractured area could not be evaluated quantitatively. CONCLUSIONS: The incidence of ICD is higher in patients with the fractured area located in the superior portion of the index vertebra and ICD might be responsible for unsatisfied pain relief after PVP for OVCFs. KEY WORDS: Percutaneous vertebroplasty, insufficient cement distribution, fractured area, risk factor, osteoporosis, vertebral compression fracture, spine, unsatisfied pain relief, cement augmentation.

The therapeutic effect of intravertebral vacuum cleft with osteoporotic vertebral compression fractures: A systematic review and meta-analysis.

BACKGROUND: To date, there has been ongoing debate over whether intravertebral vacuum cleft (IVC) has the effect of therapeutic efficacy in percutaneous vertebral augmentation (PVA) for the treatment of osteoporotic vertebral compression fractures (OVCFs). OBJECTIVE: The aim of this meta-analysis was to calculate a pooled estimate of the IVCs on the effect of therapeutic efficacy of PVA for the treatment of OVCFs. METHODS: A systematic electronic literature search was performed using the following databases: PubMed, Embase and Cochrane Library; the databases were searched from the earliest available records up to June 2016. Pooled risk ratio (RR) or a mean difference (MD) with 95% confidence interval (CI) was calculated using random- or fixed-effects models. The RevMan 5.2 was used to analyze the data. RESULTS: In the immediate postoperative period, pooled results showed that vertebral height and VAS scores of the IVC patients were significantly lower than those of the non-IVC patients. However, pooled results showed there was no significant difference in kyphotic angle and ODI indices between the two groups. At final follow-up period, significant difference was observed in all the radiological and clinical parameters for the IVC patients with compared to the non-IVC patients in our pooled results. Pooled results showed significant difference with respect to the rate of cement leakage between the two groups. CONCLUSION: The IVCs had an important effect of therapeutic efficacy in PVA for the treatment OVCFs. Therefore, we strongly recommend its strict observation and follow-up for the IVCs patients.

[COMPARISON OF EFFECTIVENESS BETWEEN PERCUTANEOUS VERTEBROPLASTY AND PERCUTANEOUS KYPHOPLASTY FOR TREATMENT OF OSTEOPOROTIC VERTEBRAL COMPRESSION FRACTURE WITH INTRAVERTEBRAL VACUUM CLEFT].

OBJECTIVE: To compare the clinical efficacy and safety between percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fracture (OVCF) with intravertebral vacuum cleft (IVC). METHODS: Between January 2010 and December 2013, 68 patients with single OVCF and IVC were treated, and the clinical data were retrospectively analyzed. Of 68 patients, 48 underwent PVP (PVP group) and 20 underwent PKP (PKP group). There was no significant difference in age, gender, disease duration, fracture level, bone mineral density (BMD), visual analogue scale (VAS), Oswestry disability index (ODI), and preoperative radiological parameters between 2 groups (P>0.05). The intraoperative incidence of cement leakage, cement volume, and operative time were compared between 2 groups; VAS score was used for evaluation of back pain and ODI for evaluation of dysfunction; the incidence of adjacent vertebral fracture was observed within 2 years. The vertebral height and kyphotic angle were measured on X-ray films; the rate of vertebral compression (CR), reduction rate (RR), progressive height loss (PHL), reduction angle (RA), and progressive angle (PA) were calculated. RESULTS: There was no significant difference in cement volume and the incidence of cement leakage between 2 groups (P>0.05). The operative time in PVP group was shorter than that in PKP group, showing significant difference (t=-8.821, P=0.000). The mean follow-up time was 2.4 years (range, 2.0-3.1 years). The VAS scores and ODI were significantly reduced at 1 day, 1 year, and 2 years after operation when compared with preoperative scores (P<0.05), but there was no significant difference between different time points after operation in 2 groups (P>0.05). Adjacent vertebral fracture occurred in 5 cases (10.4%) of PVP group and in 2 cases (10.0%) of PKP group, showing no significant difference (χ2=0.003, P=0.963). BMD was significantly increased at 1 year and 2 years after operation when compared with preoperative BMD (P<0.05), but no significant difference was found between 2 groups (t=0.463, P=0.642; t=0.465, P=0.646). The X-ray films showed that CR and kyphotic angle were significantly restored at immediate after operation in 2 groups (P<0.05); but vertebral height and kyphotic angle gradually aggravated with time, showing significant difference between at immediate and at 1 and 2 years after operation (P<0.05); there was no significant difference in CR and kyphotic angle between 2 groups at each time point (P>0.05). RR, RA, PHL, and PA showed no significant difference between 2 groups (P>0.05). CONCLUSIONS: There is similar clinical and radiological efficacy between PVP and PKP for treatment of OVCF with IVC. Re-collapse could happen after operation, so strict observation and follow-up are needed.

[CLASSIFICATION AND TREATMENT STRATEGIES OF SYMPTOMATIC SEVERE OSTEOPOROTIC VERTEBRAL FRACTURE AND COLLAPSE].

OBJECTIVE: To investigate the classification and treatment strategies of symptomatic severe osteoporotic vertebral fracture and collapse. METHODS: Between August 2010 and January 2014, 42 patients with symptomatic severe osteoporotic vertebral fracture and collapse were treated, and the clinical data were retrospectively analyzed. According to clinical symptom and imaging materials, 23 cases were classified as type I (local pain, limitation of motion, no neurological symptom, and no obvious deformity), 12 cases as type II (slight neurological symptom and kyphotic Cobb angle < or = 30 degrees), and 7 cases as type III (severe neurological symptom and kyphotic Cobb angle >30 degrees). In 23 type I patients, 17 underwent percutaneous vertebral augmentation, 6 underwent posterior pedicle screw fixation strengthened with bone cement combined with percutaneous vertebral augmentation. In 12 type II patients, they were treated with local spinal decompression and internal fixation strengthened with bone cement. In 7 type III patients, 5 underwent posterior osteotomy, and 2 underwent one stage posterior approach of vertebral resection and reconstruction. The visual analogue scale (VAS), Oswestry disability index (ODI), and local kyphotic Cobb angle were used to evaluate the neurological function. The complications were recorded. RESULTS: The operation was successfully completed in all patients. Wound infection and ketoacidosis secondary to stress blood glucose rise occurred in 1 case of type III patients respectively, and were cured after corresponding treatment; primary healing of wound was obtained in the other patients. The patients were followed up from 6 to 36 months (mean, 11.6 months). The nerve function was improved in 17 cases, and micturition disability was observed in 2 cases. Asymptomatic cement leakage occurred in 13 cases (30.95%) (7 cases in type I, 4 cases in type II, and 2 cases in type III). No bone cement dislocation and internal fixation failure were found during follow-up. The VAS score, ODI, and the local kyphotic Cobb angle at 1 week and last follow-up were significantly improved when compared with preoperative ones (P<0.05), but no significant difference was found between at 1 week and last follow-up (P>0.05). CONCLUSION: In order to improve the effectiveness and reduce the risk and complications of operation, individualized strategies should be performed according to different types of severe osteoporotic vertebral fracture and collapse.

[Correlation analysis of cement leakage with volume ratio of intravertebral bone cement to vertebral body and vertebral body wall incompetence in percutaneous vertebroplasty for osteoporotic vertebral compression fractures].

OBJECTIVE: To investigate the risk factors of cement leakage in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fracture (OVCF). METHODS: Between March 2011 and March 2012, 98 patients with single level OVCF were treated by PVP, and the clinical data were analyzed retrospectively. There were 13 males and 85 females, with a mean age of 77.2 years (range, 54-95 years). The mean disease duration was 43 days (range, 15-120 days), and the mean T score of bone mineral density (BMD) was -3.8 (range, -6.7- -2.5). Bilateral transpedicular approach was used in all the patients. The patients were divided into cement leakage group and no cement leakage group by occurrence of cement leakage based on postoperative CT. Single factor analysis was used to analyze the difference between 2 groups in T score of BMD, operative level, preoperative anterior compression degree of operative vertebrae, preoperative middle compression degree of operative vertebrae, preoperative sagittal Cobb angle of operative vertebrae, preoperative vertebral body wall incompetence, cement volume, and volume ratio of intravertebral bone cement to vertebral body. All relevant factors were introduced to logistic regression analysis to analyze the risk factors of cement leakage. RESULTS: All procedures were performed successfully. The mean operation time was 40 minutes (range, 30-50 minutes), and the mean volume ratio of intravertebral bone cement to vertebral body was 24.88% (range, 7.84%-38.99%). Back pain was alleviated significantly in all the patients postoperatively. All patients were followed up with a mean time of 8 months (range, 6-12 months). Cement leakage occurred in 49 patients. Single factor analysis showed that there were significant differences in the volume ratio of intravertebral bone cement to vertebral body and preoperative vertebral body wall incompetence between 2 groups (P < 0.05), while no significant difference in T score of BMD, operative level, preoperative anterior compression degree of operative vertebrae, preoperative middle compression degree of operative vertebrae, preoperative sagittal Cobb angle of operative vertebrae, and cement volume (P > 0.05). The logistic regression analysis showed that the volume ratio of intravertebral bone cement to vertebral body (P < 0.05) and vertebral body wall incompetence (P < 0.05) were the risk factors for occurrence of cement leakage. CONCLUSION: The volume ratio of intravertebral bone cement to vertebral body and vertebral body wall incompetence are risk factors of cement leakage in PVP for OVCF. Cement leakage is easy to occur in operative level with vertebral body wall incompetence and high volume ratio of intravertebral bone cement to vertebral body.

[Clinical application of cyanoacrylates for prevention of cerebrospinal fluid leakage].

OBJECTIVE: To explore the effectiveness of cyanoacrylates (Fuaile) for spinal subdural benign tumorectomy to prevent the cerebrospinal fluid leakage. METHODS: Between January 2009 and March 2013, 35 patients underwent spinal subdural benign tumorectomy. Of 35 patients, Fuaile and gelatin sponge were used after stitch suture for a watertight closure of the dura in 19 cases (trial group), and only gelatin sponge was used after stitch suture in 16 cases (control group). There was no significant difference in gender, age, disease duration, types of tumors, and sites of tumors between 2 groups (P > 0.05). The ratio of watertight closure, incision healing, and relative complications were compared between 2 groups. RESULTS: All patients in 2 groups achieved watertight closure of the dura intraoperatively. There was no significant difference in operation time, intraoperative blood loss, length of dura incision, hospitalization time, total drainage volume, and drainage time between 2 groups (P > 0.05). Primary incision healing was obtained; no delayed healing, infection, or nerve compression occurred in all patients. At last follow-up, the ratios of successful watertight closure of trial and control groups were 89.5% (17/19) and 50.0% (8/16) respectively, showing significant difference (P=0.02). No delayed cerebrospinal fluid leakage or incision infection was found at 1 and 3 months after operation. CONCLUSION: The application of cyanoacrylates for watertight closure of dura in spinal subdural benign tumorectomy is safe and effective.