Finite Element Analysis of a Novel Anterior Locking Plate for Thoracolumbar Burst Fracture

Purpose. The finite element analysis method was used to explore the biomechanical stability of a novel locking plate for thoracolumbar burst fracture fusion fixation. Methods. The thoracolumbar CT imaging data from a normal volunteer was imported into finite software to build a normal model and three different simulated surgical models (the traditional double-segment fixation model A, the novel double-segment fixation model B, and the novel single-segment fixation model C). An axial pressure (500 N) and a torque (10 Nm) were exerted on the end plate of T12 to simulate activity of the spine. We recorded the range of motion (ROM) and the maximum stress value of the simulated cages and internal fixations. Results. Model A has a larger ROM in all directions than model B (flexion 5.63%, extension 38.21%, left rotation 46.51%, right rotation 39.76%, left bending 9.45%, and right bending 11.45%). Model C also has a larger ROM in all directions than model B (flexion 555.63%, extension 51.42%, left rotation 56.98%, right rotation 55.42%, left bending 65.67%, and right bending 59.47%). The maximum stress of the cage in model A is smaller than that in model B except for the extension direction (flexion 96.81%, left rotation 175.96%, right rotation 265.73%, left bending 73.73%, and right bending 171.28%). The maximum stress value of the internal fixation in model A is greater than that in model B when models move in flexion (20.23%), extension (117.43%), and left rotation (21.34%). Conclusion. The novel locking plate has a smaller structure and better performance in biomechanical stability, which may be more compatible with minimally invasive spinal tubular technology.

Is Osteoporotic Thoracolumbar Burst Fracture a Contraindication to Percutaneous Kyphoplasty? A Systematic Review

BACKGROUND: The management of pain after osteoporotic thoracolumbar burst fracture has not reached a treatment consensus. Percutaneous kyphoplasty has been shown to be efficient in reducing acute pain after burst fracture, although the topic remains highly controversial in this field. OBJECTIVE: This study aimed to conduct a systematic review of the current literature to evaluate the effectiveness and safety of percutaneous kyphoplasty on the treatment of osteoporotic thoracolumbar burst fracture. STUDY DESIGN: A systematic review. SETTING: University hospital. METHODS: A comprehensive literature search was performed through PubMed, EMBASE, Web of Science, and Cochrane library without time restriction. Among the studies meeting the eligible criteria, any study in which percutaneous kyphoplasty was utilized alone in the treatment of osteoporotic thoracolumbar burst fracture was included in the current review. For radiographic outcome evaluation, vertebral height and kyphotic angle were analyzed. VAS (Visual Analog Scale) and ODI (Oswestry Disability Index) were utilized for clinical outcome evaluation. Complications such as cement leakage and adjacent vertebral fracture or relapse were also analyzed. RESULTS: In total, 289 patients (338 vertebral bodies) were included in the 8 studies. Clinical outcomes indicated that patients achieved pain relief (VAS) from 6.8 preoperatively to 1.1 postoperatively, and improvement of quality of life (ODI) ranged from 87.0 ± 6.0% to 23.9 ± 4.4%. The radiological outcome indicated that anterior vertebral height restoration ranged from 20.1 ± 2.3 to 85.3 ± 10.6, and posterior vertebral height restoration ranged from 27.3 ± 1.7 to 83.3 ± 7.4. Kyphotic angle achieved correction ranged from 21.7 ± 7.8° preoperatively to 3.17° postoperatively. The main complications after PKP were cement leakage and adjacent vertebral fracture or relapse, which had an incidence of 7.7% -45.4% and 4.3% -74.1%, respectively. LIMITATIONS: Due to the good quality of the English publications, only English-language research searches were conducted, but they do not unduly affect our aggregate results impact. More prospective randomized controlled trials are needed to provide higher evidence for clinical practice. CONCLUSIONS: To osteoporotic thoracolumbar burst fracture is absolutely not a contraindication to percutaneous kyphoplasty. Percutaneous kyphoplasty can obtain satisfactory effectiveness for the treatment of osteoporotic thoracolumbar burst fractures. Complications can be effectively decreased by meticulous evaluation, careful manipulation, and appropriate precautionary measures. KEY WORDS: Percutaneous kyphoplasty, osteoporosis, burst fracture, cement leakage, adjacent fracture

Development and validation of a nomogram for prediction of the risk of positive hidden blood loss in the perioperative period of single-level thoracolumbar burst fracture

Background This study aimed to develop and validate an individualized nomogram to predict the risk of positive hidden blood loss (HBL) in patients with single-level thoracolumbar burst fracture (TBF) during the perioperative period. Methods We conducted a retrospective investigation including 150 consecutive patients with TBL, and the corresponding patient data was extracted from March 2013 to March 2019. The independent risk factors for positive HBL were screened using univariate and multivariate logistic regression analyses. According to published literature and clinical experience, a series of variables were selected to develop a nomogram prediction model for positive HBL. The area under the receiver operating characteristic curves (AUC), C-index, calibration plot, and decision curve analysis (DCA) were used to evaluate the performance of the prediction model. Bootstrapping validation was performed to evaluate the performance of the model. Results Among the 150 consecutive patients, 62 patients were positive for HBL (38.0%). The multivariate logistic regression analysis showed that the six risk factors of age, length of surgical incision, duration of operation, percentage of vertebral height restoration (P1%), preoperative total cholesterol, and preoperative fibrinogen were independent risk factors of positive HBL. The C-index was 0.831 (95% CI 0.740–0.889) and 0.845 in bootstrapping validation, respectively. The calibration curve showed that the predicted probability of the model was consistent with the actual probability. Decision curve analysis (DCA) showed that the nomogram had clinical utility. Conclusion Overall, we explored the relationship between the positive HBL requirement and predictors. The individualized prediction model for patients with single-level TBF can accurately assess the risk of positive HBL and facilitate clinical decision making. However, external validation will be needed in the future.

Long-segment Fixation VS Short-segment Fixation Combined With Kyphoplasty for Osteoporotic Thoracolumbar Burst Fracture

BackgroundTo compare clinical and radiological results of long-segment fixation (LF) and six-screw short-segment fixation combined with kyphoplasty (SSFK) for osteoporotic thoracolumbar burst fracture (OTBF). Methods Forty patients affected by OTBF with mean age of 61.85 were included in this study. The mean follow-up period was 13.63 months. Twenty-four patients were treated by SSFK, and 16 patients were treated by LF. Clinical outcomes, radiological parameters and complications were assessed and compared. ResultsThe mean operative time and blood loss were 89.71±7.62min and 143.75±42.51ml for SFK group, respectively; 111.69±12.25min (P<0.01) and 259.38±49.05 ml (P<0.01) for LF group, respectively. The two groups were similar in terms of preoperative radiological and clinical results. Compared with preoperative values, both groups achieved significant improvement in terms of VAS, ODI, Cobb angle and anterior vertebral body height (AVH) ratio at final follow-up. However, during the follow-up period, the loss of Cobb angle and AVH ratio were significant different between immediately postoperative and final follow-up evaluations for both groups. Five cases (20.83%) of asymptomatic cement leakage were observed in SSFK group. One case of implant failure and two cases of adjacent or non-adjacent vertebral fractures were observed in LF group. ConclusionsFor the treatment of OTBF, SSFK shows similar clinical and radiological results as LF. Comparatively, SSFK is less invasive and can preserve more motion segments, which is a more valuable surgical option in selected elderly patients.

Vacuum Phenomenon As A Predictor of Kyphosis After Implant Removal Following Posterior Pedicle Screw Fixation Without Fusion For Thoracolumbar Burst Fracture: A Single-Center Retrospective Study

Background: Posterior pedicle screw fixation without fusion has been commonly applied for thoracolumbar burst fracture. Implant removal is performed secondarily after bone union. However, the occurrence of secondary kyphosis has recently attracted attention. Secondary kyphosis results in poor clinical outcomes. The purpose of this was to determine predictors of kyphosis after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture.Methods: This retrospective study reviewed 60 consecutive patients with thoracolumbar burst fracture who underwent implant removal following posterior pedicle screw fixation without fusion. Inclusion criteria were non-osteoporotic fracture and T11-L4 burst fracture. Old age, sex, initial severe wedge deformity, initial severe kyphosis, and vacuum phenomenon were examined as factors potentially associated with final kyphotic deformity (defined as kyphotic angle greater than 25°) or loss of correction. Logistic regression analysis was performed using propensity score matching.Results: Among the 31 female and 29 male patients (mean age 39 years), final kyphotic deformity was found in 17 cases (28%). Multivariate analysis showed a significant association with the vacuum phenomenon. Loss of correction was found in 35 cases (58%) and showed a significant association with the vacuum phenomenon. There were no significant associations with other factors.Conclusions: The findings of this study suggest that the vacuum phenomenon before implant removal may be a predictor of secondary kyphosis of greater than 25° after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture, but that old age, sex, initial severe kyphosis, and initial severe wedge deformity may not be predictors.

Risk Factor Analysis for Predicting Kyphosis Reoccurrence of Thoracolumbar Burst Fracture Patients Treated with Posterior Short-Segment Fixation

Background: The thresholds of risk factors of kyphosis recurrence in thoracolumbar burst fracture patients were still controversial. The aim of this multi-center study was to identify these thresholds.Methods: 169 patients were included in this study. Upper intervertebral angle (UIVA), lower intervertebral angle (LIVA), Cobb angle (CA), anterior vertebral height ratio (AVH%), regional angle (RA), posterior vertebral height ratio (PVH%), vertebral wedge angle (VWA), anteroposterior ratio (A/P%), Clinical assessment included Load Sharing Classification (LSC) score, Thoracolumbar Injury Classification and Severity (TLICS) score, Visual Analogue Scale (VAS), and Body mass index (BMI) were perioperatively evaluated. Patients were divided into KR group and none KR (NKR) group according to whether the loss of CA correction was less than 15˚ or not. The risk factors of KR before or after implant removal were analyzed, respectively. Result: There were significant improvements in postoperative parameters compared with preoperative parameters, such as AVH%, A/P%, VAS, CA, VWA, PVH% (P < 0.001, respectively), and UIVA (P = 0.02). Age (AUC = 0.828) and BMI (AUC = 0.846) were good predictors of KR before implant removal. BMI (AUC = 0.871) was a good predictor of KR after implant removal. Conclusion: There were significant differences in risk factors of KR at different postoperative follow-up stages: age > 49 years, BMI > 24 were risk factors of KR before implant removal; BMI > 25.17 was a risk factor of KR.