Objective:To analyze the revision strategies for failed atlantoaxial dislocation (AAD) surgery.Methods:A retrospective analysis was conducted on 145 patients who underwent revision surgery for AAD at the General Hospital of Southern Theatre Command of PLA between September 2009 and December 2023. The cohort included 74 males and 71 females, with a mean age of 43±16 years (range, 6-72 years). The initial surgical approaches were: anterior 31 cases, posterior 114 cases. Based on imaging assessments of immediate postoperative reduction and fusion status prior to revision, the cases of failure were classified into reduction-nonfusion type (22 cases), nonreduction-fusion type (31 cases), and nonreduction-nonfusion type (92 cases). Among the nonreduction-nonfusion cases, 39 had initial surgery with internal fixation for reduction, while 53 had initial surgery with simple decompression (posterior arch resection, foramen magnum decompression) without reduction. In the nonreduction-fusion cases, 8 cases had spot fusion and 23 had extensive fusion. Japanese Orthopaedic Association (JOA) scores were compared before and after revision, and complication rates were observed.Results:All patients successfully underwent surgery. The revision approaches included: anterior (anterior fixation and fusion 52 cases, anterior implant removal combined anterior fixation and fusion 4 cases, transoral odontoidectomies 16 cases, anterior implant removal combined transoral odontoidectomy 2 cases), posterior (posterior fixation and fusion 2 cases, posterior implant removal combined posterior fixation and fusion 22 cases), and combined anterior-posterior (posterior implant removal combined anterior fixation and fusion 18 cases, anterior implant removal combined posterior fixation and fusion 25 cases, posterior implant removal combined transoral odontoidectomy 5 cases). Operative time was 254.20±107.63 min (range, 90-660 min), and blood loss was 218.83±172.17 ml (range, 20-800 ml). Except for 3 patients who died due to postoperative complications, all patients were followed up for a duration of 12±11 months (range, 3-60 months). Six patients who failed to achieve bony fusion after the initial revision surgery underwent a second revision due to poor reduction (1 case), infection (1 case), suboptimal implant position (3 cases), and graft nonunion (1 case). All three patients with bony fusion after the initial revision surgery underwent a second revision due to poor reduction. Following the second revision surgery, none of the 9 patients exhibited graft nonunion or spinal cord compression. The 136 successful initial revision cases had a final follow-up JOA score of 14.75±2.00, significantly higher than the preoperative score of 11.93±2.92 ( t=-18.869, P<0.001). Conclusions:Revision surgery for AAD should take into account the immediate postoperative reduction status and fusion status prior to revision. An appropriate revision strategy should be selected to achieve satisfactory reduction and bony fusion.

Objective:To analyze the revision strategies for failed atlantoaxial dislocation (AAD) surgery.Methods:A retrospective analysis was conducted on 145 patients who underwent revision surgery for AAD at the General Hospital of Southern Theatre Command of PLA between September 2009 and December 2023. The cohort included 74 males and 71 females, with a mean age of 43±16 years (range, 6-72 years). The initial surgical approaches were: anterior 31 cases, posterior 114 cases. Based on imaging assessments of immediate postoperative reduction and fusion status prior to revision, the cases of failure were classified into reduction-nonfusion type (22 cases), nonreduction-fusion type (31 cases), and nonreduction-nonfusion type (92 cases). Among the nonreduction-nonfusion cases, 39 had initial surgery with internal fixation for reduction, while 53 had initial surgery with simple decompression (posterior arch resection, foramen magnum decompression) without reduction. In the nonreduction-fusion cases, 8 cases had spot fusion and 23 had extensive fusion. Japanese Orthopaedic Association (JOA) scores were compared before and after revision, and complication rates were observed.Results:All patients successfully underwent surgery. The revision approaches included: anterior (anterior fixation and fusion 52 cases, anterior implant removal combined anterior fixation and fusion 4 cases, transoral odontoidectomies 16 cases, anterior implant removal combined transoral odontoidectomy 2 cases), posterior (posterior fixation and fusion 2 cases, posterior implant removal combined posterior fixation and fusion 22 cases), and combined anterior-posterior (posterior implant removal combined anterior fixation and fusion 18 cases, anterior implant removal combined posterior fixation and fusion 25 cases, posterior implant removal combined transoral odontoidectomy 5 cases). Operative time was 254.20±107.63 min (range, 90-660 min), and blood loss was 218.83±172.17 ml (range, 20-800 ml). Except for 3 patients who died due to postoperative complications, all patients were followed up for a duration of 12±11 months (range, 3-60 months). Six patients who failed to achieve bony fusion after the initial revision surgery underwent a second revision due to poor reduction (1 case), infection (1 case), suboptimal implant position (3 cases), and graft nonunion (1 case). All three patients with bony fusion after the initial revision surgery underwent a second revision due to poor reduction. Following the second revision surgery, none of the 9 patients exhibited graft nonunion or spinal cord compression. The 136 successful initial revision cases had a final follow-up JOA score of 14.75±2.00, significantly higher than the preoperative score of 11.93±2.92 ( t=-18.869, P<0.001). Conclusions:Revision surgery for AAD should take into account the immediate postoperative reduction status and fusion status prior to revision. An appropriate revision strategy should be selected to achieve satisfactory reduction and bony fusion.

Objective To investigate the injuries caused by cholesterol to the vascular endothelial cells (VECs). Methods Different dosage of cholesterol (6.25,12.5,25.0,50.0 mg/L) was used on human umbilical endothelial cell line,ECV304,respectively. LDH activity,nitric oxide and the nitric oxide synthetase activity in the supernatant of cell culture were detected. The concentration of MCP-1 protein in cell culture was detected by ELISA. Results As compared with the normal control cells,a significant increase of LDH activity was found in the cells treated with 50.0 mg/L cholesterol. The NO level decreased in the cells treated by 25.0 or 50.0 mg/L cholesterol. When treated by cholesterol at dose of 6.25,12.5,25.0 or 50.0 mg/L respectively,the NOS activity was greatly decreased and MCP-1 protein was significantly increased in a dose-dependent manner. Conclusion Cholesterol of high concentration could directly injure the structure and partial function of VECs.