Reconstruction Of Spinal Stability Research Articles

Finite Element Analysis of Additive Manufactured Porous PEEK Artificial Vertebral Bodies in Lumbar Total En Bloc Spondylectomy

BackgroundLumbar total en bloc spondylectomy and internal fixation allows the removal of spinal tumors and the reconstruction of spinal stability. However, postoperative internal fixation failure due to unmatched spinal biomechanics remains obscure. PURPOSEThis study aimed to assess the biomechanical characteristics of additive manufactured (AM) porous polyetheretherketone (PEEK) artificial vertebral body for total en bloc spondylectomy and internal fixation. STUDY DESIGN/SETTINGComparative finite element (FE) study. METHODSWe created porous artificial vertebral bodies using medical-grade PEEK filaments and fused deposition modeling (FDM) technology, and evaluated the mechanical properties of the solid and porous implants. A finite element model of intact L1-L5 was created to analyze biomechanical characteristics of five operative constructs for reconstructing the lumbar anterior column. The lumbar anterior column was reconstructed using a titanium alloy mesh and bone graft (Ti+B) and AM PEEK artificial vertebral bodies with solid or porous structures. The maximum von Mises stresses of implants and adjacent structures were analyzed and compared under physiological conditions. RESULTSAM PEEK artificial vertebral bodies reduced von Mises stress on the artificial vertebral body, adjacent vertebral bodies, and intervertebral discs. The AM porous PEEK artificial vertebral body (PEEK-500) exhibited the lowest von Mises stress of the artificial vertebral body, adjacent vertebral bodies, and intervertebral discs. CONCLUSIONSTi+B increased the maximum stress on adjacent vertebral bodies, suggesting that it has the potential for mesh subsidence. Moreover, PEEK-500 had minimal impact on the internal implants and adjacent structures. This indicated that the lumbar anterior column reconstructed with AM porous PEEK artificial vertebral bodies may decrease the risk of postoperative internal fixation failure and adjacent segment degeneration. CLINICAL SIGNIFICANCEManufactured porous PEEK artificial vertebral bodies demonstrated a minimal impact on both the internal implants and adjacent structures. This suggests that reconstructing the lumbar anterior column with AM porous PEEK artificial vertebral bodies can decrease the risk of postoperative internal fixation failure and adjacent segments degeneration.

Thoracolumbar Burst Fracture Treatment Using Posterior Pedicle Screw Fixation and Autogenous Bulk Iliac Bone Graft Fusion

Background: Thoracolumbar vertebral fracture is the most common type of thoracolumbar vertebral fracture. For the patients with severe thoracolumbar vertebral burst fracture and neurological impairment, surgical decompression and reconstruction of spinal stability is an important intervention method, however, there is still controversy on the way of postoperative stability reconstruction. Objective: This study was to investigate the efffcacy of posterior open reduction, pedicle screw ffxation, and autogenous iliac bone graft fusion in the treatment of thoracolumbar burst fractures with neurological impairment. Methods: The clinical data of 43 patients with thoracolumbar single vertebral burst fracture with neurological function injury treated in our department from January 2016 to December 2020 were retrospectively analyzed. The Visual Analog Scale (VAS) score of lumbothoracic pain, the occupying rate of spinal canal, the ratio of the anterior height of the injured vertebral body to the normal height, Cobb angle, and the American Spinal Injury Association (ASIA) classiffcation of neurological function were compared before and after operation. All patients completed the procedure successfully. Results: Bone graft fusion was achieved in all patients, and no screw or rod was broken. The VAS score of thoracolumbar pain, the ratio of the anterior height of the injured vertebral body to the normal height, and the Cobb angle were signiffcantly lower than those before operation at 1 and 12 months after operation (P < 0.001). There was no signiffcant difference in the VAS score of thoracolumbar pain, the ratio of the anterior height of the injured vertebral body to the normal height, and the Cobb angle between 1 and 12 months after operation. The occupying rate of spinal canal 6 months after operation was lower than that before operation (12.02% ±7.35% vs. 46.98% ±9.26%), and the difference was statistically signiffcant (t = 20.066, P < 0.05). There was a signiffcant difference in ASIA classiffcation of neurological function between 12 months after operation and before operation (Z = −5.372, P < 0.001). The neurological function was signiffcantly improved 12 months after operation. Conclusion: Reconstruction of vertebral lamina with iliac bone graft is an effective method for the treatment of thoracolumbar burst fractures, which can reduce the loss of vertebral height and recurrent kyphosis and avoid the neurological impairment caused by secondary spinal stenosis.

Separation Operation Followed by Stereotactic Radiotherapy in the Treatment of Spinal Metastasis From Hepatocellular Carcinoma: A Retrospective Cohort Study.

Retrospective cohort study. Spinal metastasis from hepatocellular carcinoma is rapidly progressive and predisposes to spinal disability, cord compression and further neural injury, leading to poor prognosis. Currently, it is still challenging to look for a treatment strategy that can improve the quality of life of patients and even directly prolong the survival time. This study attempts to evaluate the clinical efficacy of separation operation combined with postoperative stereotactic radiotherapy (SRT/SRS) in the treatment of hepatocellular carcinoma patients developing spinal metastasis and epidural spinal cord compression. Patients with metastases spinal cord compression from hepatocellular carcinoma were studied retrospectively and divided into two groups, the SO group (who undergo separation operations combined with postoperative SRS, n = 32) and RT group (who received only SRS, n = 28). The visual Analogue Scale (VAS) pain score, Frankel grade, Karnofsky performance score, and Quality of Life (SF-36) score were comparatively analyzed between the two groups. Significantly higher VAS pain scores, Frankel grades, Karnofsky performance scores and Quality of Life (SF-36) scores were demonstrated in patients with combination treatment than in patients with SRS alone. Separation operations are effective surgical procedure for the treatment of spinal metastatic tumor from hepatocellular carcinoma with spinal cord compression. The combination with postoperative SRS can significantly improve the quality of life in this patient population via spinal canal decompression and spinal stability reconstruction.

Beneficial influence of single-stage posterior surgery for the treatment of lumbar brucella spondylitis combined with spondylolisthesis

We aimed to evaluate the clinical efficacy of the single-stage posterior surgical treatment for patients of lumbar brucella spondylitis combined with spondylolisthesis. In this study, we performed a retrospective analysis of 16 patients with lumbar brucellosis spondylitis combined with spondylolisthesis from January 2015 to January 2019. All patients underwent single-stage posterior lumbar debridement, reduction, interbody fusion, and instrumentation. Preoperative and postoperative of the visual analog scale (VAS), the Oswestry disability index (ODI), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were compared. In addition, the spondylolisthesis reduction rate, reduction loss rate, interbody fusion rate, and complication rate were recorded. VAS, ODI, ESR, and CRP were conducted with repeated analysis of variance data at different follow-ups. The postoperative follow-up was 12–36 months, with an average of (25.0 ± 8.1) months. VAS, ODI, ESR, and CRP were significantly better at 2-week and 1-year follow-up than preoperative results (P = 0.000, respectively). In addition, 1 year after the operation, VAS, ODI, ESR, and CRP showed a significant improvement (P = 0.000, respectively). The average spondylolisthesis reduction in 2 weeks after operation was (91.2 ± 6.7)%, and the median reduction loss rate in 1 year after operation was 8.0 (5.0, 9.8)%. At the last follow-up, all patients achieved interbody fusion, no loosening and fracture of instrumentation were found, and no recurrence happened. Single-stage posterior operation for lumbar debridement, reduction, interbody fusion, and instrumentation is beneficial for treating lumbar brucellosis spondylitis combined with spondylolisthesis. Furthermore, the reconstruction of spinal stability may relieve pain, heal lesions, and improve patients’ living.

Comparison of percutaneous pedicle screw placement under O-arm navigation with traditional percutaneous pedicle screw placement in patients with thoracolumbar fractures without neurological symptoms

Objective: To investigate the accuracy and clinical efficacy of percutaneous pedicle screw placement under O-arm navigation and traditional fluoroscopy in patients with thoracolumbar fractures without neurological symptoms. Methods: From July 2016 to July 2018, 72 patients with thoracolumbar fractures in Peking University International Hospital without neurological symptoms were divided into two groups, group A and group B. In group A, 36 patients underwent the surgery of percutaneous pedicle screw implantation under traditional fluoroscopy and 168 pedicle screws were inserted. In group B, 36 patients underwent the surgery of percutaneous pedicle screw implantation under O-arm guided fluoroscopy and 164 pedicle screws were inserted by the same surgeon. The general condition, operation condition, radiation dose, fluoroscopy time of single screw, screw placement time and accuracy, visual analogue score (VAS) score, Oswestry dysfunction index (ODI), kyphosis Cobb's angle, anterior edge height of 1 week and 6 months after surgery were compared. The data were compared with paired t test between the two groups. Results: There was no significant differences between the two groups in general condition, intraoperative blood loss, length of hospital stay, VAS, ODI, kyphosis Cobb's angle, and anterior edge height of the injured vertebra (all P>0.05). The operation time was (99±14) min in group A and (75±10) min in group B, the average screw setting time was (15.8±2.6) min in group A and (11.8±3.3) min in group B, the fluoroscopy time of each screw was (38.0±2.0) s in group A and (28.5±2.8) s in group B, the radiation dose of each surgery was (563±163) cGy/cm(2) in group A and (378±70) cGy/cm(2) in group B; the above-mentioned data of group A were all superior to those in group B and the differences between the two groups were all statistically significant (t=8.48, 5.73, 16.30, 6.25, all P<0.05). Rampersaud grading in group A was better than group B, and the differences between the two groups was statistically significant(χ(2)=12.2, P<0.05). Conclusion: The O-arm navigation system could not only provide high-definition navigation images and achieve high-precision navigation operations, which is more accurate than traditional pedicle screws placement, but also contribute to the reconstruction of spinal stability and reduce radiation dose, pedicle screws placement and operating time.

Radiological and Clinical Differences between Tinavi Orthopedic Robot and O-Arm Navigation System in Thoracolumbar Screw Implantation for Reconstruction of Spinal Stability.

BackgroundPedicle screw fixation is one of the most commonly used methods in spine surgery. We introduce a surgical robot system from China based on 3-dimensional fluoroscopy imaging and compare it with the commonly used O-arm navigation system. We study the differences in accuracy, safety, and clinical effect in auxiliary pedicle screw fixation.Material/MethodsPatients who underwent thoracolumbar internal fixation in our hospital from 2017 to 2019 were divided into a robot and navigation group according to whether surgery was assisted by the Tinavi orthopedic robot or O-arm navigation system. Imaging data of patients were searched from the image system and accuracy of screw implantation was measured by Rampersaud A to D grade classification. Deviation sagittal, deviation transversal, and facet joint violation were also measured and calculated.ResultsIn total, 306 patients were included: 136 patients in the robot group with 760 screws implanted; 166 patients in the navigation group with 908 screws implanted. The accuracy of “perfect” and “clinically acceptable” pedicle screw implantation was 96.2% and 99.6%, respectively, in the robot group and 90.5% and 96.7%, respectively, in the navigation group, with a significant difference between the 2 groups (P<0.05). The sagittal and transversal deviations in the robot group were significantly less than those in the navigation group (P<0.05).ConclusionsThe Tinavi orthopedic robot can significantly improve surgical accuracy and safety of pedicle screw fixation, as compared with that of O-arm navigation technology, without increasing complications. It shows great potential in clinical application.

An aneurysmal bone cyst ruptured and compressed the spinal cord: a case report

Spinal aneurysmal bone cyst (ABC) is a rare benign bone lesion with various prognosis. Common clinical symptoms of spinal ABCs include local pain, swelling. But we presented a case of a teenager girl who exhibited symptoms of acute thoracic cord compression after a slight trauma and was then diagnosed with ABC in her thoracic spine. A unique aspect is that this patient did not have symptoms before she fell down on her hip, and had an acute worsening of her neurological deficits. In the vast majority of cases, for a teenager, the trauma on the spine is tiny after falling down on the hips. That is the reason we initially felt confused before she had an urgent CT scan. In order to achieve early decompression of the thoracic cord and stabilization of the local spine around T4, we proceeded with urgent lesion resection and pedicle screws fixation from T2 to T5 to remove the liquid containing cyst and achieve spinal stability. Postoperative pathology indicated the lesion was an ABC. The patient gained good neurological recovery without any adverse effect in the final follow-up. We believe spinal ABC of teenagers can have no symptoms until a slight trauma leading to acute neurological deficits. Careful preparing for emergency surgery, prompt resection of the lesion as well as spinal stability reconstruction can promote good recovery and minimal adverse effect.

Massive Spondylectomy for Metastatic Spinal Cord Compression From Non-Small-Cell Lung Cancer With Local Failure After Radiotherapy.

Study Design.:A retrospective multivariate analysis.Objective.:To analyze clinical outcomes of surgical treatment and prognostic factors of local failure after stereotactic body radiation therapy (SBRT) in patients with spinal metastatic non–small-cell lung cancer (NSCLC).Methods.:This study included patients with metastatic spinal cord compression (MSCC) from spinal NSCLC after radiotherapy who received massive spondylectomy for circumferential decompression of spinal cord and reconstruction of spinal stability in our center between May 2006 and February 2017. Neurological function was evaluated using the Frankel score. Overall survival (OS) was estimated by the Kaplan-Meier method. Factors with Pvalues ≤.1 were subjected to multivariate analysis for OS by proportional hazard analysis. Values of P<.05 were considered statistically significant.Results.:The mean age of the 55 included patients (36 male and 19 female) was 57.76 ± 8.94 (median 58, range 36-77) years, with a mean postoperative OS of 14.98 ± 14.81 (median 10.0, range 1-84) months. Neurological function was improved in 46 (83.6%) of the 55 patients after surgery. Prognostic analysis suggested that preoperative frankel score (FS) score, visceral metastasis, D-dimer (D-D) level, and neutrophil/lymphocyte ratio (NLR) were independent prognostic factors for selected patients.Conclusions.:Massive spondylectomy could provide circumferential decompression and improve the neurological function of patients with MSCC from spinal NSCLC after radiotherapy. A preoperative FS score of C/D, no visceral metastasis, D-D <1000 μg/L, and NLR <5 are predictors of better prognosis.

Tissue-engineered bone used in a rabbit model of lumbar intertransverse process fusion: A comparison of osteogenic capacity between two different stem cells.

Spinal fusion serves an important role in the reconstruction of spinal stability via restoration of the normal spinal sequence and relief of pain. Studies have demonstrated that the fusion rate is mainly associated with the osteogenic capacity of the implanted graft. Mesenchymal stem cells (MSCs) have been successfully isolated from human degenerated cartilage endplate (CEP) and designated as CEP-derived stem cells (CESCs). Previous studies have suggested that CESCs possesses in vitro and in vivo chondrogenic potential superior to that of bone marrow (BM)-MSCs. In addition, CESCs have shown a stronger in vitro osteogenic ability. The present study aimed to further determine the in vivo three-dimensional osteogenesis efficacy of CESCs for spinal fusion. Tissue-engineered bone grafts were transplanted into a rabbit model of posterolateral lumbar intertransverse process fusion using CESCs and BM-MSCs as seed cells composited with porous hydroxyapatite (PHA). The results of manual palpation and computed tomography (CT) scan reconstruction indicated that the CESCs/PHA group had a higher fusion rate than the BM-MSCs/PHA group, although the difference was not observed to be statistically significant. In addition, RT-qPCR results revealed that the in vitro CESCs/PHA composite expressed significantly higher levels of osteogenic-specific mRNA compared with the BM-MSCs/PHA composite. Finally, micro-CT and semi-quantitative histological analysis further demonstrated that the newly formed bone quality of the CESCs/PHA group was significantly higher than that of the BM-MSCs/PHA group in the intertransverse process fusion model. Therefore, the study indicated that CESCs possess superior in vivo osteogenesis capacity compared with BM-MSCs, and might serve as an important alternative seed cell source for bone tissue engineering. These results may provide the foundation for a biological solution to spinal fusion or other bone defect issues.

Debridement and Interbody Graft Using Titanium Mesh Cage, Posterior Monosegmental Instrumentation, and Fusion in the Surgical Treatment of Monosegmental Lumbar or Lumbosacral Pyogenic Vertebral Osteomyelitis via a Posterior-Only Approach

The main objective of the present study was to analyze the efficacy and feasibility of surgical management for patients with monosegmental lumbar or lumbosacral pyogenic vertebral osteomyelitis (PVO) by using one stage posterior debridement, interbody graft using titanium mesh cage, posterior monosegmental instrumentation, and fusion. From February 2014 to May 2016, 27 patients with lumbar or lumbosacral PVO were treated by posterior debridement, interbody graft using titanium mesh cage, posterior monosegmental instrumentation, and fusion. The degree of damage to the patients' vertebral bodies was one third to one half height. There were 16 male and 11 female, with a mean age of 43.5 years (range, 32-56 years) at the time of surgery. The mean follow-up time was 35.7 months (range, 26-53 months). The clinical efficacy was evaluated on average operation time, blood loss, visual analog scale, erythrocyte sedimentation rate, C-reactive protein level, and neurologic function recovery. PVO was completely cured and the grafted bone was fused in all 27 patients. There was no recurrent vertebral osteomyelitis infection. Erythrocyte sedimentation rate and C-reactive protein level achieved normal limits within 3 months in all patients. The American Spinal Injury Association neurologic classification was improved in all cases. Pain relief was obtained in all patients. Our results showed that one stage posterior debridement, interbody graft using titanium mesh cage, posterior monosegmental instrumentation, and fusion was an effective treatment for patients with one third to one half height of vertebral body damaged in monosegmental lumbar or lumbosacral PVO. The surgical method is characterized as minimum surgical trauma, good pain relief, good neurologic recovery, and good reconstruction of spinal stability.

Biomechanical analysis of a novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body: a finite element study

BackgroundTo compare the biomechanical properties of a novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body (HAVB) with the titanium mesh cage (TMC) and artificial vertebral body (AVB), and evaluate its biomechanical efficacy in spinal stability reconstruction.MethodsA 3D nonliner FE model of the intact L1-sacrum was established and validated. Three FE models which instrumented HAVB, TMC, and AVB were constructed for surgical simulation. A pure moment of 7.5 Nm and a 400-N preload were applied to the three FE models in 3D motion. The peak von Mises stress upon each prosthesis and the interfaced endplate was recorded for analysis. In addition, the overall and intersegmental range of motion (ROM) of each model was investigated to assess the efficacy of each model in spinal stability reconstruction.ResultsAVB had the greatest stress concentration compared with TMC and HAVB in all motions (25.6–101.8 times of HAVB, 0.8–8.1 times of TMC). The peak stress on HAVB was 3.1–10.3% of TMC and 1.6–3.9% of AVB. The maximum stress values on L2 caudal and L4 cranial endplates are different between the three FE models: 0.9–1.9, 1.3–12.1, and 31.3–117.9 times of the intact model on L2 caudal endplates and 0.9–3.5, 7.2–31.5, and 10.3–56.4 times of the intact model on L4 cranial endplates in HAVB, TMC, and AVB, respectively, while the overall and segmental ROM reduction was similar between the three models, with AVB providing a relatively higher ROM reduction in all loading conditions (88.1–84.7% of intact model for overall ROM and 69.5–82.1% for L1/2, 87.0–91.7% for L2/4, and 71.1–87.2% for L4/5, respectively).ConclusionsHAVB had similar biomechanical efficacy in spinal stability reconstruction as compared with TMC and AVB. The material used and the anatomic design of HAVB can help avoid stress concentration and the stress shielding effect, thus greatly reducing the implant-associated complications. HAVB exhibited some advantageous biomechanical properties over TMC and AVB and may prove to be a potentially viable option for spinal stability reconstruction. Further in vivo and vitro studies are still required to validate our findings and conclusions.

Application of 3D O-arm-navigated pedicle screw insertion in spinal stability reconstruction in patients with spinal cord and spinal column tumors

Objective To explore the advantages of O-arm-navigated pedicle screw insertion in patients with spinal column and spinal cord tumors. Methods We retrospectively enrolled 29 patients with spinal tumors who underwent pedicle placement using O-arm-based navigation (Group A, 21 cases) or freehand technique (Group B, 8 cases) at Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, Tsinghua University from October 2015 to December 2017. Screw position was judged on the 3D O-arm images and the accuracy of screws placement was evaluated according to the Gertzbein-Robbins scale. The clinical data and neuroimaging data were collected during the follow-up. Results Age, sex, body mass index, mean blood loss, length of stay and radiation dose showed no significant difference (all P>0.05) between the 2 groups. The operation time in group A was longer than that in group B (109.7±59.9 min vs. 74.5±19.4 min, P=0.025). A total of 134 screws were inserted in Group A and 117 screws was classified as grade A, 11 as grade B and 6 as grade C. There were 45 screws inserted in group B and 34 screws were classified as grade A, 4 as grade B, 6 as grade C and 1 as grade D. The accuracy of screw inserting was significantly different between the 2 groups (group A: 95.5% and group B: 84.4%, χ2=4.604, P=0.032). No screw-related neurovascular complications occurred. Conclusion O-arm-based navigation system could markedly improve the accuracy of screw insertion and thus help reconstruct spinal stability. Key words: Spinal cord neoplasms; Spinal neoplasms; Neuronavigation; O-arm; Spinal fixation

Five-year outcomes of posterior affected-vertebrae fixation in lumbar tuberculosis patients

BackgroundPosterior instrumentation after deformity correction is an important method for reconstruction of spinal stability in the management of lumbar tuberculosis (TB). However, the commonly used methods include both long- and short-segment fixation of normal motor units. There has been no report regarding affected-vertebrae fixation of lumbar TB.MethodsData from 135 patients with lumbar TB who underwent posterior instrumentation and either affected-vertebrae fixation or short-segment fixation using a combined posterior and anterior approach were retrospectively reviewed. Among these patients, 71 cases were treated with affected-vertebrae fixation, and 64 cases were treated with short-segment fixation. Debridement, bone grafting, deformity correction, and decompression were performed within all affected segments. Operative times, intra-operative blood loss, TB cure rates, bone graft fusion rates, degree of deformity correction, neurological function, pain recovery, and complications were analyzed.ResultsComparing affected-vertebrae fixation vs. short-segment fixation groups, respectively, the number of the affected segments was 107 vs. 98; average number of affected segments was 1.51 vs. 1.53; total number of fixed segments was 107 vs. 226; average number of fixed segments was 1.51 vs. 3.53; average blood loss was 726.2 ml vs. 948.5 ml; average operative time was 210.4 min vs. 270.3 min; and average hospitalization costs were 29,000 RMB vs. 42,000 RMB (all p values < 0.05). In the affected-vertebrae fixation vs. short-segment fixation groups, respectively, TB cure rates were 82.61% vs. 84.62% at 6 months after operation and 97.83% vs. 97.44% at 5 years after operation; bone fusion rates were 86.96% vs. 87.18% at 6 months after operation and 97.83% vs. 97.66% at 5 years after operation; average number of degrees of Cobb’s angle correction were 13.1° vs. 13.7°; average correction losses were 1.9° vs. 1.4°; and complication rates were 12.04% vs. 12.97% (all p values > 0.05).ConclusionUnder strict surgical indications, posterior instrumentation on affected-vertebrae is a safe, effective, and feasible fixation method in the treatment of lumber TB.

Recurrent complex spinal tuberculosis accompanied by sinus tract formation: causes of recurrence and clinical treatments

Recurrent complex spinal tuberculosis accompanied by sinus tract formation is one of the most common and complex types of recurrent tuberculosis. To date, only very few studies have reported the strategies and effectiveness of surgical treatments on postoperative recurrent spinal tuberculosis accompanied by sinus tract formation. In this study, 21 recurrent patients out of 87 patients with complex spinal tuberculosis were reviewed. The data of the patients, including age, gender, existence of drug-resistant mycobacterium tuberculosis, postoperative standard chemotherapy, completeness of lesion debridement, reconstruction of the spinal stability, nutritional status, accompaniment by tuberculosis in other regions, timing of the operations, and areas of the lesions, were collected for single- and multiple-factor analyses. The clinical outcomes were evaluated by long-term follow-ups. The results showed that 7 factors were significantly associated with postoperative recurrence of complex spinal tuberculosis accompanied by sinus tract formation. This suggested that when we treat complex spinal tuberculosis, we should pay more attention to these seven indicators to avoid postoperative recurrence, and our clinical outcomes suggested that it is difficult to treat recurrent complicated spinal tuberculosis combined with sinus tract formation. The key for successful surgical treatment includes effective chemotherapy, radical debridement and proper reconstruction of spinal stability.

Accuracy of a patient-specific template for pedicle screw placement compared with a conventional method: a meta-analysis.

Accurate placement of pedicle screws in spine surgery is a challenge for surgeons. Patient-specific template techniques have the potential for improving the accuracy of screw placement. The target of this analysis was to investigate differences in terms of accuracy of pedicle screw insertion between patient-specific template assistance and the conventional free-hand method for reconstruction of spinal stability. The Cochrane Library, Ovid, Web of Science, PubMed, EMBASE and CNKI database were searched until February 2017 for a systematic review, and several comparative studies were screened for comparisons of accuracies of pedicle screw insertion with patient-specific assistance and conventional methods. Primary outcomes extracted from papers that met the selection criterion were expressed as odds ratios for dichotomous outcomes with a 95% confidence interval. A χ 2 test and I 2 statistics were used to evaluate heterogeneity. A total of ten RCTs and two prospective cohort studies were finally chosen for the analysis of accuracy rates. Study quality was assessed using the Cochrane Collaboration's Tool and Newcastle-Ottawa Quality Assessment Scale. There were obvious differences between them, and the accuracy rate of screw implantation among a patient-specific template assistance set was statistically significantly higher than the conventional free-hand set (OR 95% CI 3.78-6.41, P<0.01); in vitro: OR 95% CI 3.93-7.42, P<0.01; in vivo: OR 95% CI 2.49-6.44, P<0.01. The template-assisted technique is superior to the conventional method for the reduction of pedicle violation. The template-assisted technique is a promising technique that should be considered as another available navigation tool for surgeons to improve the accuracy of pedicle screw placement. As an available technique for emerging applications in spine surgeries, this technique will face challenges but ultimately prove successfully.

The causes and surgical strategy of spinal tuberculosis retreatment

Objective To investigate the causes of spinal tuberculosis retreatment and its surgical treatment strategy. Methods Between May 2010 and May 2014, 96 patients with spinal tuberculosis who had been operated before were retreated. The dates of them were reviewed. There were 51 males and 45 females with mean age of 39.7 years. Deciding upon the revision surgical procedure should be determined by last operation approach, the direction of compression of spinal cord, the position of sinus and extent of foci. The retreated patients were compared with 481 unretreated patients in the following index including sex, age, duration of disease, focus range, nutrition, drug resistant tuberculosis, debridement, stability of instrumentation, postoperative regular chemotherapy, associated tuberculosis. Results The surgery duration time was 160-280 min, average 210 min, and the blood loss was 400-1500 ml, average 600 ml. The VAS score before the operation was 6-9 (average 7.5) and 1-3 (average 1.5) at the last follow-up, the difference was statistically significant. Neurological deficits in 21 patients clinically improved at least one grade according to the ASIA grading system at last follow-up. Kyphosis and scoliosis degrees were corrected significantly postoperatively and the correction was 9.5°±3.6° at the final follow-up. The average angle loss was 3.5°±1.1°. There was significant difference between the kyphosis angles preoperatively, postoperatively and final follow-up. Kirkaldy-Willis function score showed that the total fine rate was 88%. There were 35 patients whose tuberculosis bacterial culture and drug sensitive experiments suggested drug resistance. Wound healing delayed in 7 patients. 24 cases had sinus formation, 13 cases in which were healed after wound dressing, and 11 cases undertook operation again. Conclusion The causes of spinal tuberculosis retreatment include uncompleted debridement, drug resistant strains of tuberculosis, irregular postoperative anti-tubercular treatment, poor preoperative nutritional status and failure of spinal stability reconstruction. The key of successful revision surgery includes radical debridement, strut grafting with autologous iliac bone block, proper reconstruction of spinal stability, individualized chemotherapy according to the drug-resistance, and the appropriate use of irrigation and drainage postoperatively. Key words: Tuberculosis; Spinal diseases; Risk factors; Clinical protocols

Atlantoaxial instability secondary to eosinophilic granuloma of the axis in adults: long-term follow-up in six cases

Background contextEosinophilic granuloma (EG) involving the spine is uncommon in adults. Atlantoaxial instability (AAI) secondary to EG of the axis in adults is an extremely rare clinical condition that can give rise to severe neurologic morbidity or mortality if not treated appropriately. There have been no previous reports on the condition in adults. PurposeTo present the outcome and clinical experience for the management of AAI secondary to EG of the axis in adults. Study designA retrospective review study. Patient sampleAll adult patients with AAI secondary to EG of the axis who were admitted to the spine service at the study institution between January 1999 and April 2012. Outcome measuresClinical symptoms, neurologic status, radiologic manifestations, treatment, outcome, and/or complications were recorded and analyzed. MethodsSix consecutive adults who presented clinical and radiographic manifestations of AAI secondary to EG of axis were treated and monitored. All patients were treated surgically with anterior tumor resection and posterior reconstruction of spinal stability. Oral steroid therapy was administered after surgery as adjuvant therapy. ResultsThe mean duration of follow-up was 77 months (range, 37–140 months). The most common radiographic feature was osteolytic destruction of the vertebral body of the axis. All patients had favorable recoveries, with osseous fusion. There were no surgery-related postoperative complications, and neither recurrence nor spinal deformity had occurred by the final follow-up examination. ConclusionsSurgical intervention via anterior tumor resection and posterior reconstruction was found to be safe and effective for treating AAI secondary to EG in adults, in terms of recovering neurologic function, improving symptom relief, and reducing the risks resulting from osteolytic destruction. Surgical treatment plus oral steroid therapy can produce beneficial results and definitive local control during the follow-up period.

Surgical management of schwannomas in spinal eloquent areas

Objective To investigate the clinical characteristics and surgical management of schwannomas in spinal eloquent areas. Methods Clinical data of 58 patients with schwannomas in spinal eloquent areas was retrospectively studied. All the tumors were excised by microsurgery assisted with intraoperative neurophysiological monitoring. If the tumor originated from cervical enlargement, somatosensory-evoked potentials (SEPs) and motor-evoked potentials (MEPs) of both upper and lower extremities and EMG of upper extremities were performed. If the tumor originated from intumescentia lumbalis and conus medullaris, SEPs and MEPs of lower extremities and EMG of lower extremities and sphincter ani were performed. All the tumors were excised through posterior median approach. Laminectomy or hemilaminectomy was chosen according to the size and location of tumors. The internal fixation was accepted for the reconstruction of spinal stability if facetectomy was performed. The intraoperative neurophysiological monitoring could be helpful during the procedure of internal fixation. Results Total resection was achieved in all of the 58 patients. There was no new neurological deficit after surgery. The preoperative pain symptoms in 42 patients disappeared in 39 patients and relieved obviously in 3 patients after operation. Twenty-two patients had numbness on the involved nerve root dominate regions, and maybe it was concerned with the resection of tumors and parent nerve roots. The preoperative weakness symptoms in 17 patients and constipation symptoms in 2 patients were significantly improved when discharge. One patient with severe weakness of bilateral lower extremities and 2 patients with sphincter dysfunction were transferred to Physiatry Department when their condition became stable. During the follow-up period of 3-12 months, the preoperative neurological deficit improved significantly and there was no tumor recurrence. Conclusion The intraoperative neurophysiological monitoring can reduce the rate of neurological complications for schwannomas originated from spinal eloquent areas, such as intumescentia lumbalis and conus medullaris. doi：10.3969/j.issn.1672-6731.2013.11.004 Video: http://www.cjcnn.org/index.php/cjcnn/pages/view/v13n11a4

Reconstruction of spinal stability for intra-and extra-spinal tumor in operation

Objective To investigate the preservation and reconstruction of spinal stability for intro-and extra-spinal tumor in operations.Methods Clinical data of 26 patients with intra-and extra-spinal tumor were retrospectively studied.The bone was destroyed by tumor severely in 16 patients,the bone was not destroyed by tumor or destroyed not so severely in 10 patients,but the facetectomy was needed for the removal of tumor.Hemilaminectomy and facetectomy was performed in 20 cases,and laminectomy and facetectomy was performed in 6 cases.The tumor was excised through the posterior approach in 23 patients,and through the posterior approach combined with the anterior approach in 3 patients.The pedicular screw fixation was performed in all the vertebral body except cervical 3 to 7 in which the lateral mass screw fixation was performed.Results All patients began exercising with the support of a simple external brace within 3 weeks postoperatively,there was no displacement or fracture of the instrumentation of internal fixation,and no spinal spondylolisthesis and deformity were observed.Conclusions The spinal stability was destroyed in operation because of facetectomy and laminectomy; sometimes,the spinal stability can be destroyed by the tumor because of bone erosion pre-operatively.Internal fixation should be performed for the reconstruction of spinal stability. Key words: Intra-and extra-spinal tumor; Spinal stability; Internal fixation

Treatment of thoracolumbar tumors with total en bloc spondylectomy and the results of spinal stability reconstruction

To investigate the therapeutic effect of total en bloc spondylectomy (TES) for thoracolumbar tumors and the results of spinal stability reconstruction. From January 2007 to June 2011 there were 18 patients with thoracolumbar tumors distributed in the thoracic vertebrae (n = 10) and lumbar vertebrae (n = 8). There were 7 haemangiomas, 5 giant cell tumors of bone, 1 malignant schwannoma, 1 solitary plasmocytoma, 1 neuroblastoma, 1 osteoblastoma, 1 metastatic malignant fibrous histiocytoma, and 1 metastasis of breast cancer. All the 18 patients were treated with improved TES under electrophysiological monitoring of spinal cord. Four patients were treated through one-stage combined anteroposterior approach and 14 patients through one-stage posterior approach. The anterior reconstructions included titanium mesh cages filled with bone or bone cement in 15 cases, titanium mesh cage with strengthened rings in 2 cases and artificial vertebral body replacement in 1 case. The posterior reconstruction included multiple segmental fixation with pedicle screw-rod system in 15 cases and short segmental fixation in 3 cases. Massive bone auto-graft was employed in 13 cases and fragmental bone graft in 5 cases. The total en bloc spondylectomy was performed successfully in 15 patients and unsuccessful in 3 whose spinal tumors were resected by piecemeal technique. In 15 patients with successfully performed TES, the duration of surgery was from 340 to 610 min (average, 450.7 min), the blood loss was from 3000 to 10 200 ml (average, 4850 ml), and the intraoperative blood transfusion was from 2800 to 9600 ml (average, 4200 ml). The operation-related complications comprised hemopneumothorax, intercostal nerve pain, stress ulcer and bleeding, and so on. One year after operation, the patients with neurological dysfunction recovered from grade A to grade D in one patient, and to grade E in the other 14 cases. The average visual analog scale (VAS) scores was 0.5. One patient with plasmacytoma and another one with L5 metastatic tumor suffered progression of the disease and were living with the diseases. The patient with metastatic malignant fibrous histiocytoma died of local recurrence and lung metastasis 16 months postoperatively. One patient with L4 neuroblastoma died of other reason and all the rest were free from relapse. The Cobb angle of upper and lower vertebral body adjacent to the involved vertebrae in sagittal plane was from -26.7° to 12.0° (average, -2.57°) just postoperatively and from -17.5° to 57.2° (average, 11.5°) at the last follow-up or before reoperation. There were 2 patients with screw-rod breakdown and 2 patients with internal fixation loosening. The measurement of titanium mesh cage subsided into adjacent vertebral bodies was average 7.5 mm. The revision surgery was performed in 3 patients, through combined anteroposterior approach in 2 and only posterior approach in 1 patient. TES significantly increases the therapeutic effect of spinal tumors, although accompanied with high difficulty and massive bleeding. In spinal stability reconstruction after total spondylectomy, it should be emphasized that posterior long segment fixation with pedicle screw-rod system, massive bone bridging graft and the application of thoracolumbosacral orthosis can achieve short-term firm fixation and long-term fusion-stabilization.