BACKGROUND:The cervical pedicle screws provide ideal three-column stability for cervical vertebra, but there is stil no a standard with the choice of pedicle screw place methods in cervical vertebra. Here, we try to seek a simpler, safer and accurate pedicle screw place method.OBJECTIVE:To evaluate the accuracy and security of transpedicular screw placement assisted by rapid prototyping individual navigation template. METHODS:Eight cadaver cervical specimens (C3-6) were selected to take CT-scan and data were saved in DICOM format. Three-dimensional (3D) software MIMICS was used to establish the C3~6 3D model, and designed the best pedicle screw channel. According to the morphological feature of the posterior cervical spine elements, the reverse template was designed. Then, the best pedicle screw channels were fused into bilateral navigation template. The navigation template was manufactured by rapid prototyping, and saved in STL format. Rapid prototyping technology was used to print out the navigation template. Cervical pedicle screws were inserted with the assistance of navigation templates fitted with the posterior structure of the vertebral body. Postoperative X-ray and CT scan were used to evaluate the accuracy of screw placement. RESULTS AND CONCLUSION:(1) Total y 64 screws were inserted with the assistance of individual navigation templates. Of them, 62 screws were completely in the pedicle;1 screw perforated the medial cortex of pedicle;1 screw perforated the lateral cortex of pedicle. Accuracy of screw placement was 97%. (2) The individual navigation template with a high accuracy rate is a feasible and safe method for cervical pedicle screw placement, which has great prospects for clinical application.

Objective:To investigate the efficacy of stage I anterior cervical reduction, decompression, interbody fusion and internal fixation of single-segment lower cervical injury of AO type C subtype F4.Methods:A retrospective case series study was made on 45 patients with single-segment lower cervical injury of AO C type F4 subtype admitted to Zhengzhou Orthopedic Hospital from January 2012 to December 2019. The study included 31 males and 14 females with the age of (48.5±3.7)years (range, 23-78 years). Segment of injury was located at C 4/5 in 11 patients, at C 5/6 in 19, and at C 6/7 in 15. Under general anesthesia, all patients (16 unilateral injury and 29 bilateral injury) underwent stage I anterior cervical reduction, decompression, interbody fusion and internal fixation within 24 hours after injury. The interbody fusion methods included autogenous iliac bone in 28 patients and cervical fusion cage in 17. The operation time, blood loss, reduction time and correction rate of zygapophysial joints, postoperative complications and incision healing were analyzed. The height of cervical intervertebral space and Cobb angle were measured through X-ray of lateral cervical vertebrae before operation and3 months after operation to assess the cervical physiological curvature. The type of injury was clarified according to Lenke classification through coronal and sagittal CT scanning to determine the intervertebral bone graft fusion rate. The intraspinal spinal cord decompression was observed through MRI. The nerve function was assessed before operation and 3 months after operation using American Spinal Injury Association (ASIA) scale and Japanese Orthopedic Association (JOA) score, and the improvement rate was measured. Results:All the patients were followed up for (6.1±3.6)months (range, 3-9 months). The operation time was (55.1±8.2)minutes (range, 40-75 minutes), and intraoperative blood loss was (45.2±5.3)ml (range, 40-80 ml). The Zygapophysial joint reduction took (2.1±0.5)minutes (range, 1.5-3.0 minutes), with a success rate of 100%. Surgical procedures were performed with no postoperative complications such as aggravated spinal cord injury, large vascular injury or esophageal lesion. All the patients obtained Class I incision healing at first stage. The height of cervical intervertebral space was improved from preoperative (3.3±0.6)mm to (4.9±0.8)mm at postoperative 3 months ( P<0.05). The Cobb angle was increased from preoperative (-4.6±3.6)° to (6.5±2.1)° at postoperative 3 months ( P<0.01). According to Lenke classification, the intervertebral body fusion was good at postoperative 3 months, including Grade A in 41 patients and Grade B in 4. The rest of the patients showed varying degrees of neurological recovery according to ASIA scale, except for 6 patients with ASIA Grade A. The JOA score was improved from preoperative (7.4±2.3)points to (15.0±3.2)points at postoperative 3 months ( P<0.05), with the improvement rate of (73.3±17.6)%. Conclusion:For stage I anterior cervical reduction, decompression, interbody fusion and internal fixation of single-segment lower cervical injury of AO type C subtype F4, early surgical decompression is needed so as to reduce the perched facet or dislocated zygapophyseal joints and effectively improve the cervical spinal cord function.

Objective:To investigate the efficacy of the classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine.Methods:A retrospective case series study was made on 105 patients with single segment facet joint dislocation in subaxial cervical spine admitted to Zhengzhou Orthopedic Hospital from January 2015 to October 2022. There were 63 males and 42 females, with the age range of 22-78 years [(47.5±3.6)years]. Preoperative American Spinal Cord Injury Association (ASIA) classification was grade A in 23 patients, grade B in 45, grade C in 22, grade D in 15 and grade E in 0. The classification of surgical approach was based on the presence or not of continuity between anterior and posterior subaxial cervical structures and the movability of the posterior cervical facet joint on CT two-dimensional images, including anterior cervical surgery if both were presented and posterior facet joint resection plus anterior cervical surgery if there was discontinuity between anterior and posterior subaxial cervical structures or posterior facet joint fusion. Reduction procedures were applied in accordance with the type of facet joint dislocation classified based on the position of the lower upper corner of facet joint, including skull traction or manipulative reduction for the dislocation locating at the dorsal side (type A), intraoperative skull traction and leverage technique for the dislocation locating at the top (type B) and intraoperative skull traction and leverage technique with boosting for the dislocation locating at the ventral side (type C). If the dislocation of two facet joints in the same patient was different, the priority of management followed the order of type C, type B and type A. The reduction success rate, operation time and intraoperative blood loss were recorded. The cervical physiological curvature was evaluated by comparing the intervertebral space height and Cobb angle before operation, at 3 months after operation and at the last follow-up. The fusion rate of intervertebral bone grafting was evaluated by Lenke grading at 3 months after operation. The spinal cord nerve injury was assessed with ASIA classification before operation and at 3 months after operation. Japanese Orthopedic Association (JOA) score was applied to measure the degree of cervical spinal cord dysfunction before operation and at 3 months after operation, and the final follow-up score was used to calculate the rate of spinal cord functional recovery. The occurrence of complications was observed.Results:All patients were followed up for 3-9 months [(6.0±2.5)months]. The reduction success rate was 100%. The operation time was 40-95 minutes [(58.6±9.3)minutes]. The intraoperative blood loss was 40 to 120 ml [(55.7±6.8)ml]. The intervertebral space height was (4.7±0.3)mm and (4.7±0.2)mm at 3 months after operation and at the last follow-up, significantly decreased from preoperative (3.1±0.5)mm (all P<0.01), but there was no significant difference in intervertebral space height at 3 months after operation and at the last follow-up ( P>0.05). The Cobb angle was (6.5±1.3)° and (6.3±1.2)° at 3 months after operation and at the last follow-up, significantly increased from preoperative (-5.4±2.2)° (all P<0.01), but there was no significant difference in Cobb angle at 3 months after operation and at the last follow-up ( P>0.05). The fusion rate of intervertebral bone grafting evaluated by Lenke grading was 100% at 3 months after operation. The ASIA grading was grade A in 15 patients, grade B in 42, grade C in 29, grade D in 12 and grade E in 7 at 3 months after operation. The patients showed varying degrees of improvement in postoperative ASIA grade except that 15 patients with preoperative ASIA grade A had partial recovery of limb sensation but no improvement in ASIA grade. The JOA score was (13.3±0.6)points and (13.1±0.6)points at 3 months after operation and at the last follow-up, significantly improved from preoperative (6.8±1.4)points (all P<0.01), but there was no significant difference in JOA score at 3 months after operation and at the last follow-up ( P>0.05). The rate of spinal cord functional recovery was (66.3±2.5)% at the last follow-up. All patients had no complications such as increased nerve damage or vascular damage. Conclusion:The classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine has advantages of reduced facet joint dislocation, recovered intervertebral space height and physiological curvature, good intervertebral fusion and improved spinal cord function.

Objective:To explore the efficacy of stage I modified posterior vertebral column resection (mPVCR) in the treatment of postoperative infection after percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fracture (OVCF).Methods:A retrospective case series study was conducted to analyze the clinical data of 11 OVCF patients with post-PVP infection who were admitted to Zhengzhou Orthopedics Hospital from January 2016 to June 2022, including 4 males and 7 females, aged 61-81 years [(70.2±6.4)years]. Injured segments included T 9 in 1 patient, T 11 in 2, T 12 in 3, L 1 in 1, L 2 in 2, T 11-T 12 in 1, and T 12-L 1 in 1. American Spinal Injury Association (ASIA) grading was grade D in 5 patients and grade E in 6. All the patients were treated with stage I mPVCR. The operation time and intraoperative bleeding volume were recorded. The values of Visual Analogue Scale (VAS), Oswestry Dysfunction Index (ODI), and Cobb angle of the lesion segments before, at 2 weeks, 3 months after surgery, and at the last follow-up were compared. The loss of Cobb angle of the lesion segments at 2 weeks after surgery and at the last follow-up were compared, and the ASIA grading at the last follow-up was recorded. The infection control, bone healing, and the incidence of complications were observed at the last follow-up. Results:All the patients were followed up for 12-44 months [(26.0±9.4)months]. The operation time and intraoperative bleeding volume were 230-330 minutes [(279.2±28.6)minutes] and 500-1 100 ml [(840.9±184.1)ml] respectively. At 2 weeks, 3 months after surgery and at the last follow-up, the VAS scores were (4.0±0.8)points, (2.7±0.9)points, and (2.4±0.7)points respectively, which were all lower than that before surgery [(8.1±1.2)points] ( P<0.01); the ODI was (45.5±5.1)%, (30.0±6.5)%, and (18.5±3.6)% respectively, which were all lower than that before surgery [(78.7±6.2)%] ( P<0.01); the Cobb angle of the lesion segments were (7.9±1.4)°, (8.5±1.4)°, and (9.2±1.5)° respectively, which were lower than that before surgery [(25.5±9.2)°] ( P<0.01). The VAS and ODI were both improved at 3 months after surgery compared with those at 2 weeks after surgery ( P<0.05), while there was no significant difference in Cobb angle of the lesion segments ( P>0.05). The ODI was further improved at the last follow-up compared with that at 3 months after surgery ( P<0.05), while there were no significant differences in VAS or Cobb angle of the lesion segments ( P>0.05). The loss of Cobb angle correction of the lesion segment at the last follow-up was 0.96 (0.69, 1.45)° compared with that at 2 weeks after surgery and the rate of loss of Cobb angle correction of the lesion segment was 4.4(2.2, 7.4)%. At the last follow-up, the ASIA grading was grade E for all the patients, who were able to walk normally independently. The infection was all cured and good bony fusion was observed in the operated area at the last follow-up. Two patients had pleural effusion and pulmonary atelectasis, 1 incision fat liquefaction, and 1 pneumonia after the surgery. None of the patients had internal fixation failure and serious complications such as worsening neurological symptoms or death. Conclusion:Stage I mPVCR for the treatment of post-PVP infection in patients with OVCF is proved to attain significant pain relief and functional improvement, good correction results, effective reconstruction of spinal stability, complete removal of infected lesions, and few serious complications.

Objective:To investigate the efficacy of one-stage posterior-anterior combined operation for the treatment of abnormal fusion after facet joint dislocation in the subaxial cervical spine.Methods:A retrospective study of case series was conducted to analyze the clinical data of 10 patients with abnormal fusion after facet joint dislocation in the subaxial cervical spine who had been admitted to Department of Spine Surgery, Zhengzhou Orthopedic Hospital from January 2015 to May 2023. There were 7 males and 3 females with an age of (41.2±3.1) years. Preoperative American Spinal Injury Association (ASIA) grading: 5 cases of grade A, 4 cases of grade B, and 1 cases of grade C. All the patients were treated with one-stage posterior-anterior combined operation. The surgical time and intraoperative bleeding volume were recorded. The ASIA grading was used to evaluate the improvements in nerve function of the spinal cord 3 months after surgery. The VAS scores, cervical intervertebral heights, and Cobb angles were compared between pre-surgery, 3 months after surgery, and the last follow-up. The fusion of intervertebral bone graft was evaluated 3 months after surgery using the Bridgell intervertebral fusion criteria. Complications were observed.Results:All patients were followed up for 15.5 (13.8, 20.5) months. The surgical time was (119.5±3.6) minutes, and the intraoperative bleeding volume (141.6±25.6) mL. Significant improvements in VAS score, cervical intervertebral height, and Cobb angle were observed at 3 months after surgery and the last follow-up compared with the pre-surgery values ( P<0.05), but there was no statistically significant difference between 3 months after surgery and the last follow-up ( P>0.05). ASIA grading 3 months after surgery: 4 cases of grade A, 4 cases of grade B, and 2 cases of grade C. By the Bridgell intervertebral fusion criteria at 3 months after surgery: 9 cases of grade Ⅰ and 1 cases of grade Ⅱ, showing good intervertebral fusion. Surgery went on well for all patients, showing no postoperative complications such as aggravation of nerve lesion or vascular injury. Conclusion:In the treatment of abnormal fusion after facet joint dislocation in the subaxial cervical spine, the efficacy of one-stage posterior-anterior combined operation is definite because it can effectively reduce pain, restore the height and physiological curvature of the cervical intervertebral space, and achieve good intervertebral fusion.