Replantation of lamina spinous process ligament complex and miniature titanium plate shaping internal fixation in the treatment of tumors in the spinal canal.

OBJECTIVE: Purpose This study aims to explore the clinical efficacy of laminospinous process ligament complex reimplantation combined with mini-titanium plate fixation in the treatment of thoracolumbar intraspinal tumors. METHODS: A retrospective analysis was performed on 43 cases of intraspinal tumors treated with thoracolumbar intraspinal tumor resection from August 2018 to March 2021, and 27 cases underwent laminospinous process ligament complex reimplantation combined with micro titanium plate shaping. Fixation (laminar replantation group), and 16 patients underwent laminectomy combined with pedicle screw internal fixation (laminectomy group). The operation time, blood loss, drainage tube removal time, cerebrospinal fluid leakage, spinal instability, and the incidence of secondary spinal stenosis were compared between the two groups. The pain VAS score, ODI score, and modified Macnab at the last follow-up were compared between the two groups. And the laminar fusion rate of the laminoplasty group was measured. RESULTS: Both groups successfully completed the surgery and obtained complete follow-up. The incidence of cerebrospinal fluid leakage and secondary spinal canal stenosis in the laminectomy group was lower than that in the laminectomy group, and the difference was statistically significant (P < 0.05). There was no statistically significant difference in the incidence of spinal instability between the two groups (P > 0.05). The operation time and intraoperative blood loss in the laminectomy group were less than those in the laminectomy group, and the drainage tube removal time was earlier than that in the laminectomy group. The difference was statistically significant (P < 0.05). At the final follow-up, there was no statistically significant difference in the pain VAS score, ODI score, and modified Macnab between the two groups (P > 0.05), but they were all significantly improved compared with preoperative ones. Fusion evaluation was conducted on the laminoplasty group. Two years after surgery, the fusion rate was 97.56% (40/41). CONCLUSIONS: The application of laminospinous process ligament complex reimplantation combined with mini titanium plate fixation during thoracolumbar intraspinal tumor resection can effectively reconstruct the spinal canal and posterior column structure, reduce the incidence of cerebrospinal fluid leakage and secondary spinal stenosis. The laminar fusion rate is high.

Combined use of tranexamic acid and rivaroxaban in posterior lumbar interbody fusion safely reduces blood loss and transfusion rates without increasing the risk of thrombosis-a prospective, stratified, randomized, controlled trial.

PURPOSE: This prospective, stratified, randomized, single-blind, placebo-controlled multicentre study investigated the safety and effectiveness of reducing blood loss and preventing venous thromboembolism (VTE) during posterior lumbar interbody fusion (PLIF) in patients with stenosis or spondylolisthesis using the combination of tranexamic acid (TXA) and rivaroxaban. METHODS: The Autar score was evaluated in patients after admission. Patients with an Autar score ≤ 10 were randomized to group A or B. Group A was the placebo-controlled group. Patients in group B were treated with 1 g TXA via intravenous injection and 1 g TXA for external use. Patients with an Autar score > 10 were randomized to group C or D. Patients in group C were treated with 10-mg rivaroxaban qd for 35 days after surgery. Patients in group D received the same treatment as those in group B intra-operatively and as those in group C post-operatively. RESULTS: A total of 599 patients from eight hospitals participated in this clinical trial. The total blood loss, intra-operative blood loss, and drainage volume were reduced by the administration of TXA (group A vs group B, P < 0.01; group C vs group D, P < 0.01), and the blood transfusion rate was also decreased (group A vs group B, P < 0.01; group C vs group D, P < 0.01). There were no significant differences (P > 0.05) in the VTE incidence rates among group A and group B. In patients with high-risk thrombosis, the number of patients with VTE was only three and seven after the application of rivaroxaban. Epidural haematoma was not discovered in any patients in our trial. CONCLUSION: The combined application of tranexamic acid and rivaroxaban significantly reduced the amount of blood loss and the transfusion rate during PLIF surgery and avoided an increase in the probability of thrombosis and the occurrence of epidural haematoma. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: ChiCTR-1800016430 2018-06-01.

Biomimetic porous silk fibroin/biphasic calcium phosphate scaffold for bone tissue regeneration.

The purpose of our study is to prepare a biomimetic porous silk fibroin (SF)/biphasic calcium phosphate (BCP) scaffold, and evaluate its performance in bone tissue regeneration. The differences in pore size, porosity, mechanical strength and biocompatibility of four different fibroin-containing scaffolds (0, 20, 40, and 60% SF) were studied in vitro. After inoculation with MC3T3-E1 cells, the ectopic bone formation ability of the SF/BCP bionic scaffold was evaluated in a rat model. The SEM and CT demonstrated that compared with pure BCP group (0% SF), the pore size and porosity of SF/BCP scaffolds were proportional to SF content, of which 40% of SF and 60% of SF groups were more suitable for cell growth. The compressive strength of SF/BCP scaffold was greater than that of the pure BCP scaffold, and showed a trend of first increasing and then decreasing with the increase of SF content, among which 40% of SF group had the maximum compressive strength (40.80 + 0.68) MPa. The SF/BCP scaffold had good biocompatibility, under the electron microscope, the cells can be smoothly attached to and propagated on the scaffold. After loading the osteoblasts, it showed excellent osteogenic capacity in the rat model. The SF/BCP scaffold can highly simulate the micro-environment of natural bone formation and can meet the requirements of tissue engineering. The SF/BCP biomimetic porous scaffold has excellent physical properties and biocompatibility. It can highly simulate the natural bone matrix composition and microenvironment, and can promote the adhesion and proliferation of osteoblasts. The SF/BCP scaffold has good ectopic osteogenesis after loading with osteoblasts, which can meet the requirements of scaffold materials in tissue engineering, and has broad application prospects in clinical application.

[Observation of lumbar zygapophyseal joints adjacent arterials by anatomy and DSA].

OBJECTIVE: To investigate the arterials adjacent to the lumbar zygapophyseal joints by anatomy and DSA and aimed to provide a safe operation way for the lumbar back and posterolateral surgery by reducing operative hemorrhage in clinical treatment. METHODS: We selected 20 adult corpse lumbar departments and discovered the lumbar lateral artery and lumbar transverse process artery. Using anatomical microscope to observe the lumber transverse process artery and dosal artery of 1-4 lumber arteries from the lumbar spine 1/2-4/5. We also selected 20 patients without lumbar disease and used DSA to research their lumbar arteries and the starting, mutation or branch line of other artery sources in vivo. RESULTS: The anatomy and DSA results showed that the original location of dorsal branch usually at the anterosuperior of L1/2-4/5 foramen intervertebrale outlet area, then distributed to the outside and backside of ZJ. Anterior branch of transverse process sent out and branch into ascending and descending muscle branch. The ascending branch distributed to the below root of upper ZJ and sent out zygapophyseal branches which were distributing to the back of ZJ. The descending branch distributed to the upper root of below ZJ and sent out several muscle branches which were going into muscles in the front. And there were no statistically significant difference between left and right in the body. CONCLUSIONS: The routes of arteries adjacent to ZJ and the relationship between them showed obvious regularity. Mastering its anatomical characteristics could effectively reduce the posterior surgical bleeding, make the operation easier, reduce the important tissue damage and then avoided the postoperative hematoma complications.

Closed Reduction for the Treatment of Traumatic Thoracolumbar Spondylolisthesis.

OBJECTIVE: Thoracolumbar traumatic spondylolisthesis is a relatively rare phenomenon and has poor prognosis due to serious spinal cord or cauda equina injuries. In such cases, closed reduction is a method for restoring the vertebral sequence and may play an important role in the treatment process, although whether it is actually feasible for patients with this condition requires further investigation. The present study included 9 patients with serious thoracolumbar traumatic spondylolisthesis to determine the advantages of closed reduction over total reduction through open surgery. METHODS: Data from 9 patients (cases 1-9), diagnosed with severe thoracolumbar traumatic spondylolisthesis between June 2012 and August 2023, were retrospectively reviewed. Five patients were treated with closed reduction in an emergency department and subsequently underwent delayed internal fixation surgery at least 48 hours after the injury, and 4 with similar serious injuries underwent emergency surgery. The incidence of complications and recovery of the spinal cord or cauda equina were compared between groups. RESULTS: There were no significant differences in demographic characteristics or adverse events between the 2 groups. The reduction group had a shorter surgical duration and less blood loss than the surgery group. Although patients in the surgery group may have experienced more pain, there were no significant differences between the groups in Oswestry Disability Index or Japanese Orthopaedic Association scores. Thus, regardless of whether closed reduction was chosen, patients experienced a similar quality of life for a relatively prolonged period. CONCLUSIONS: Closed reduction may be feasible for serious thoracolumbar traumatic spondylolisthesis, although the safety of this method requires further research.

Safety and efficacy of one-hole split endoscope technique for surgical treatment of thoracic ossification of the ligamentum flavum.

Surgical intervention is typically recommended for thoracic ossification of the ligamentum flavum (TOLF). This study aimed to evaluate the efficacy and safety of a novel non-coaxial one-hole split endoscope (OSE) technique for treating TOLF. We performed OSE procedure on 13 patients with TOLF from June 2022 to July 2023. The mean operative time was 117.5 ± 15.4 min. VAS scores for lower limbs decreased from 6.5 ± 0.8 preoperative to 1.6 ± 0.4 at the last follow-up (P < 0.001). ODI scores improved from 62.4 ± 5.7 preoperative to 18.6 ± 2.2 at the last follow-up (P < 0.001), and mJOA scores increased from 5.1 ± 1.6 preoperative to 8.4 ± 1.5 at the latest follow-up (P < 0.001). All patients achieved ASIA scale grade D or E at the final follow-up, except for two patients remained residual limb numbness. None of the thirteen patients suffered from severe perioperative complications. The OSE technique proves to be a safe and effective procedure for treating TOLF or even with dura mater ossification, characterized by minimal surgical trauma, relatively smooth learning curve and flexible operation.

[Effectiveness analysis of posterolateral approach lumbar interbody fusion assisted by one-hole split endoscope for L4, 5 degenerative lumbar spondylolisthesis].

Objective: To compare the effectiveness of posterolateral approach lumbar interbody fusion assisted by one-hole split endoscope (OSE) and traditional posterior lumbar interbody fusion (PLIF) in the treatment of L4, 5 degenerative lumbar spondylolisthesis (DLS). Methods: The clinical data of 58 patients with DLS who met the selection criteria admitted between February 2020 and March 2022 were retrospectively analyzed, of which 26 were treated with OSE-assisted posterolateral approach lumbar interbody fusion (OSE group) and 32 were treated with PLIF (PLIF group). There was no significant difference between the two groups in terms of gender, age, body mass index, Meyerding grade, lower limb symptom side, decompression side, stenosis type, and preoperative low back pain visual analogue scale (VAS) score, leg pain VAS score, Oswestry disability index (ODI), and the height of the anterior and posterior margins of the intervertebral space (P>0.05). The operation time, intraoperative blood loss, postoperative hospital stay, and complications were compared between the two groups. The low back pain and leg pain VAS scores and ODI before operation, at 1 month, 6 months after operation, and last follow-up, the height of anterior and posterior margins of the intervertebral space before operation, at 6 months after operation, and last follow-up, the modified MacNab criteria at last follow-up after operation were used to evaluate the effectiveness; and the Bridwell method at last follow-up was used to evaluate the interbody fusion. Results: Both groups successfully completed the operation. Compared with the PLIF group, the OSE group showed a decrease in intraoperative blood loss and postoperative hospital stay, but an increase in operation time, with significant differences (P<0.05). In the OSE group, no complication such as nerve root injury and thecal sac tear occurred; in the PLIF group, there were 1 case of thecal sac tear and 1 case of epidural hematoma, which were cured after conservative management. Both groups of patients were followed up 13-20 months with an average of 15.5 months. There was no complication such as loosening, sinking, or displacement of the fusion cage. The low back pain and leg pain VAS scores, ODI, and the height of anterior and posterior margins of the intervertebral space at each time point after operation in both groups were significantly improved when compared with those before operation (P<0.05). Except for the VAS score of lower back pain in the OSE group being significantly better than that in the PLIF group at 1 month after operation (P<0.05), there was no significant difference in all indicators between the two groups at all other time points (P>0.05). At last follow-up, both groups achieved bone fusion, and there was no significant difference in Bridwell interbody fusion and modified MacNab standard evaluation between the two groups (P>0.05). Conclusion: OSE-assisted posterolateral approach lumbar interbody fusion for L4, 5 DLS, although the operation time is relatively long, but the postoperative hospitalization stay is short, the complications are few, the operation is safe and effective, and the early effectiveness is satisfactory.

Phase I 270° single-incision percutaneous spinal endoscopy for decompression treatment of thoracic spinal stenosis.

This study aimed to explore the feasibility of Phase I percutaneous spinal endoscopy with a 270° single incision in the ventral and dorsal dura mater for decompression treatment of thoracic spinal stenosis (TSS). Phase I percutaneous spinal endoscopy with a two-path (posterior and posterolateral approaches) single incision with a 270° decompression was performed in four cases of TSS with compression in the ventral and dorsal dura mater. The affected intervertebral space was located during the surgery, and the ossified ligamentum flavum in the ventral and dorsal dura mater was removed via laminectomy, which formed a decompression space in the thoracic cord. Next, posterolateral transforaminal expansion and plasty were performed to remove the ventral intervertebral disk. The visual analogue scale (VAS) score, thoracic spinal cord function score of the Japanese Orthopaedic Association (JOA) (11-point method), and Oswestry Disability Index (ODI) scores were used to evaluate the clinical efficacy. No dura mater or thoracic nerve injury occurred during the surgery. The symptoms of weakness in the lower extremities improved after the surgery. The postoperative magnetic resonance imaging and computed tomography examinations showed compression removal and dura mater bulging. The postoperative VAS, JOA, and ODI scores improved compared with the preoperative scores. Two surgical trajectories, posterior and posterolateral approaches, were established by a single incision using thoracic spinal canal decompression with Phase I 270° single-incision percutaneous spinal endoscopy. The posterior approach was performed mainly by translaminar unilateral fenestration and bilateral decompression in the ventral and dorsal dura mater, whereas the posterolateral approach was performed by decompression in the ventral dura mater to the midline of the vertebrae. This surgical method could be applied as a safe and feasible minimally invasive treatment for TSS with compression on both the ventral and dorsal dura mater.

[Imaging study and clinical application of unilateral biportal endoscopy technique for upper lumbar disc herniation via contralateral approach].

Objective: To investigate the relationships between the bony structures, nerve, and indentations of ligamentum flavum of the upper lumbar spine by using CT three-dimensional reconstruction technique, in order to guide the unilateral biportal endoscopy (UBE) technique via contralateral approach in the treatment of upper lumbar disc herniation (ULDH). Methods: Twenty-one ULDH patients who were admitted between June 2019 and July 2021 and met the selection criteria were selected as the research subjects. There were 12 males and 9 females with an average age of 62.1 years (range, 55-72 years). The disease duration was 1-12 years (mean, 5.7 years). There was 1 case of L 1, 2, 4 cases of L 2, 3, and 16 cases of L 3, 4. The CT myelography data of T 12-S 3 segment was saved in DICOM format and imported into Mimics21.0 software for three-dimensional reconstruction. The relationship between the intersection (point Q) of spinous process and the inferior margin of lamina, the indentation of superior margin of ligamentum flavum, the inferior margin of nerve root origin, intervertebral space, and foramen were observed. The Mimics21.0 software was used to create a 3-mm-diameter cylinder to simulate the UBE channel and measure its abduction angle (∠b1), as well as measure the following lumbar vertebra-related indicators: in L 1,2-L 3,4 segments, the vertical distance from the point Q to the inferior margin of the contralateral lumbar pedicle of the same lumbar vertebra (a1), the superior margin of the contralateral pedicle of the lower lumbar vertebra (a2), the lower endplate of the same lumbar vertebra (a3), the upper endplate of the lower lumbar vertebra (a4); the vertical distance from the lower endplate of lumbar vertebra to the inferior margin of the lumbar pedicle (c1), the vertical distance from the upper endplate of the lower lumbar vertebra to the superior margin of the lumbar pedicle (c2); the vertical distance from the inferior margin of the nerve root origin to the superior margin (d1) and the inferior margin (d2) of the lumbar pedicle, respectively; the vertical distance from the intersection (point P) of the indentation of superior margin of ligamentum flavum and the medial margin of the lumbar pedicle to the superior margin (e1) and the inferior margin (e2) of the lumbar pedicle, respectively; the horizontal distance from the lateral margin of the dural mater (f1) and the narrowest part of the lumbar isthmus (f2) to the facet joint space, respectively. Thirteen of the patients included in the study chose the UBE surgery via contralateral approach. There were 8 males and 5 females with an average age of 63.3 years (range, 55-71 years). The disease duration was 2-12 years, with an average of 6.2 years. There were 3 cases of L 2, 3 and 10 cases of L 3, 4. The perioperative complications and surgical decompression were recorded. And the effectiveness were evaluated by visual analogue scale (VAS) score, Oswestry disability index (ODI), and short form-36 health survey (SF-36) score. Results: The imaging results showed that there was no significant difference in a1, a3, a4, e1, e2, f1, and f2 between segments ( P>0.05), and there were significant differences ( P<0.05) in a2 and c2 between L 1, 2 and L 3, 4 segments, in ∠b1 and d2 between L 1, 2, L 2, 3 segments and L 3, 4 segments, and in c1 and d1 between L 1, 2 and L 2, 3, L 3, 4 segments. The 87.30% (110/126) of point Q of L 1, 2-L 3, 4 segments corresponded to the inferior articular process, and 78.57% (99/126) of the lower endplate corresponded to the level of the isthmus. All 13 patients completed the UBE surgery via contralateral approach, and none were converted to open surgery. All patients were followed up 12-17 months (mean, 14.6) months. The VAS score of low back pain and leg pain, ODI, and SF-36 score at 6 and 12 months after operation significantly improved when compared with those before operation ( P<0.05), and further improved at 12 months after operation when compared with 6 months after operation ( P<0.05). The imaging review results showed that the herniated disc was removed and the dura mater was decompressed adequately. Conclusion: The point Q, the superior margin of ligamentum flavum, and lumbar pedicle can be used as the markers for the treatment of ULBD with UBE surgery via contralateral approach, making the procedure safer, more precise, and more effective.

Upper endplate nonunion after transcorporeal percutaneous endoscopic cervical discectomy: A case report.

BACKGROUND: Transcorporeal percutaneous endoscopic cervical discectomy (TcPECD) destroys the integrity of the vertebral body. We herein discuss its long-term risks and avoidance measures. Case presentation: A 44-year-old woman underwent TcPECD. Although her upper limb symptoms were relieved after the operation, the bone channel did not heal and the endplate of the segment was altered. She consequently developed chronic neck and shoulder discomfort. CONCLUSION: Careful preoperative planning is needed to avoid non-healing of the bone channel following TcPECD. The diameter of the bony channel should be as small as possible and the channel should be opened at the posterior edge of the upper endplate to avoid collapse.

[Application of three-dimensional reconstruction simulation to define the starting point of lumbar cortical bone trajectory].

OBJECTIVE: CT three-dimensional reconstruction technology was used to simulate the placement of the lumbar cortical bone trajectory (CBT), to determine the starting point and direction of the screw trajectory. METHODS: Between February 2017 and April 2018, 24 patients with lumbar CT were selected as the study object. There were 7 males and 17 females, with an average age of 50.4 years (range, 37-68 years). The CT DICOM data of patients were imported into Mimics 16.0 software, and the three-dimensional model of lumbar spine was established. A 5 mm diameter cylinder was set up to simulate the CBT by using Mimics 16.0 software. According to the different implant schemes, the study was divided into groups A, B, and C, the track of the screw respectively passed through the upper edge, the medial edge, and the lower edge of the isthmus of the pedicle. The intersection of simulated screw and lumbar spine was marked as region of interest (ROI) and a mask was generated. The average CT value [Hounsfield unit (HU)] and the screw length of ROI were automatically measured by Mimics 16.0 software. In addition, the head inclination angle and head camber angle of the screw were measured respectively. Point F was the intersection of the level of the lowest edge of the transverse process and the lumbar isthmus periphery. The horizontal and vertical distance between point F and the starting point were measured, and the relationship between the three schemes and the position of the zygapophysial joint and spinous process was observed. RESULTS: Plan A has the highest ROI average HU, with the maximum value appearing in L 4; plan B has the longest screw length, with the maximum value appearing in L 5; plan C has the largest nail track head inclination angle, with the maximum value appearing in L 4; plan B has the largest nail track head camber angle, with the maximum value appearing in L 3. The screw length and head camber angle of the nail in group B were significantly greater than those in groups A and C ( P<0.05); the head inclination angle in groups A, B, and C was gradually increased, showing significant differences ( P<0.05); there was no significant difference in the average HU value of ROI between the 3 groups ( P>0.05). In plan A, 74.48% (143/192) screws had a horizontal distance of -2 to 4 mm from point F, a vertical distance of 6-14 mm from point F, a head inclination angle of (14.64±2.77)°, and a head camber angle of (6.55±2.09)°, respectively; in plan B, 84.58% (203/240) screws had a horizontal distance of 1-6 mm from point F, a vertical distance of 1-5 mm from point F, a head inclination angle of (26.93±2.21)°, and a head camber angle of (10.29±2.46)°, respectively; in plan C, 85.94% (165/192) screws had a horizontal distance of -2 to 3 mm from point F, a vertical distance of -2 to 4 mm from point F, a head inclination angle of (33.50±3.69)°, and a head camber angle of (6.47±2.48)°, respectively. CONCLUSION: Plan B should be selected as the starting point of the L 1-L 5 CBT implant. It is located at the intersection of the lowest horizontal line of the transverse process root and the lateral edge of the lumbar isthmus, which is 1-6 mm horizontally inward, 1-5 mm vertically upward, with a head inclination angle of (26.93±2.21)°, and a head camber angle of (10.29±2.46)°, respectively.

Screening of disorders associated with osteosarcoma by integrated network analysis.

Osteosarcoma is a common malignant bone tumor in children and adolescents under the age of 20. However, research on the pathogenesis and treatment of osteosarcoma is still insufficient. In the present study, based on gene-phenotype correlation network, an analysis was performed to screen disorders related to osteosarcoma. First, we analyzed the differential expression of osteosarcoma in two groups according to different types of osteosarcoma and screened the differentially expressed genes (DEGs) related to osteosarcoma. Further, these DEG coexpression modules were obtained. Finally, we identified a series of regulatory factors, such as endogenous genes, transcription factors (TFs), and ncRNAs, which have potential regulatory effects on osteosarcoma, based on the prediction analysis of related network of gene phenotypes. A total of 3767 DEGs of osteosarcoma were identified and clustered them into 20 osteosarcoma-related dysfunction modules. And there were 38 endogenous genes (including ARF1, HSP90AB1, and TUBA1B), 53 TFs (including E2F1, NFKB1, and EGR1), and 858 ncRNAs (including MALAT1, miR-590-3p, and TUG1) were considered as key regulators of osteosarcoma through a series of function enrichment analysis and network analysis. Based on the results of the present study, we can show a new way for biologists and pharmacists to reveal the potential molecular mechanism of osteosarcoma typing, and provide valuable reference for different follow-up treatment options.

Biomechanical comparison of percutaneous posterior endoscopic cervical discectomy and anterior cervical decompression and fusion on the treatment of cervical spondylotic radiculopathy.

BACKGROUND: Cervical spondylotic radiculopathy is a common spinal disease. The traditional surgical treatment consists of anterior cervical decompression and fusion (ACDF), but it presents problems such as trauma and fusion complications. Percutaneous posterior endoscopic cervical discectomy (PPECD) is a new minimally invasive technology that has produced good clinical outcome, but further biomechanical comparisons are needed to guide the clinical work. The goal of this study was to compare the biomechanical characteristics of the two methods by finite element analysis. METHOD: On the basis of the computed tomography scanning data of five cases of cervical spondylosis after PPECD surgery, five cases after ACDF surgery, and five non-surgical patients, software (Mimics 15.0, HyperMesh 12.0, and Abaqus 6.13) was adopted to establish a C1-C7 segment 3D finite element model. We also applied 50 N vertical load on the C1 surface and 1.5 Nm torque, simulated the anteflexion, rear protraction, and left and right lateral flexion and rotation, and observed the stability, stress distribution, and Cobb angular change of the surgical section of the cervical vertebra under different working conditions. RESULT: The postoperative model under different working conditions demonstrated poorer stability than the non-surgical group, but the stability of the PPECD group was close to that of the non-surgical group. The stability of the ACDF group was the worst, especially when making lateral bending and posterior extension. The ACDF group also showed significant differences. The PPECD group showed uniform stress distribution, whereas the ACDF group was under large stress, which was primarily concentrated in the internal fixation system. In addition, the implant showed the potential for fracture. The Cobb angle of surgery section of the PPECD group was smaller than that of the ACDF group, and the stability of the section was good. CONCLUSION: From the perspective of finite element analysis, the cervical vertebrae after PPECD treatment showed good biomechanical performance and stability.

[Imaging and biomechanics researches of reconstructing lumbosacral stability after L 5 vertebrectomy via anterolateral approach].

Objective: To investigate the feasibility of anterolateral approach for L 5 vertebral resection, bone grafting, and screw rod fixation by imaging and biomechanics researches. Methods: Twenty formalized adult cadavers (12 males and 8 females) were randomly divided into 2 groups; L 5 vertebral resection, bone graft, and screw rod fixation was performed on 10 specimens by using anterolateral approach (experimental group), and on the other 10 specimens by combined anterior and posterior approach. CT scanning and three-dimensional reconstruction were performed in the experimental group; preoperative maximal safe entry angle and depth of screws and intraoperative actual entry angle and depth of screws were measured; the sacral screw position was observed after operation. The biomechanical test was done in 2 groups. Results: Twenty specimens smoothly underwent L 5 excision and reconstruction. CT scan showed that there was no significant difference in maximal safe entry angle and depth of screws between males and females in experimental group before operation ( P>0.05); the maximal safe entry angle and depth were 51.93° and 47.88 mm for anterior screw, and were 37.04° and 46.28 mm for posterior screw. After operation, depth of the sacral anterior and posterior screws were appropriate, which did not pierce into the spinal canal. The biomechanical test results indicated that the flexion, extension, and lateral flexion displacements, and vertical compression stiffness showed no significant difference between 2 groups ( P>0.05). Conclusion: For L 5 lesions not invading posterior column, to use L 5 vertebral resection, bone graft, and screw rod fixation by anterolateral approach is a safe and feasible method to reconstruct lumbosacral stability, with the advantages of no changing posture, less operation time and incision, and prevention of bone graft shift, but effectiveness need further be identified.