[Objective]To observe the clinical results of a hollow compression nail applied to treat the separation of elements of neural arch.[Method]Since February,2003,sixteen cases of separation of elements of neural arch have been treated with a hollow compression nail and bone grafting .The mean age of the group was 32,from 18 to 54.Five cases of separation of elements of neural arch located at L4 and the other 11 at L5.All the patients suffered from severe back pain.During the operation,the presence of the pars interarticularis defect was confirmed.The defects were cleared of any fibrous and cartilaginous tissues.The sclerotic bone margins were curetted until bleeding was noted .Autograft harvested from posterior ilium was done.The hollow compression nail was placed onto the index vertebra.[Result]All the patients were followed-up for more than 14 months (14～26 months).The significant back pain relief was found in all the cases.The bony healing was comfirmed in 11 cases,and the other 5 were in the process of bone growth.[Conclusion]The separation of elements of neural arch can be treated by the hollow compression nail without spinal fusion.The hollow compression nail is proved to be safe and effective.

Objective To explore the effects of single rectangle cage interbody fusion combined with pedicle screw fixa?tion for isthmic spondylolisthesis. Methods Data of the 34 cases with isthmic spondylolisthesis hospitalized at our department from March 2012 to February 2015 were retrospectively analyzed. All cases were operated by posterior pedicle screw fixation com?bined with single rectangle cage interbody fusion. There were 21 males and 13 females, aging from 18 to 63 years old (with an aver?age age of 41.6±8.2 years). Lesion segments were L4 in 15 cases and L5 in 19 cases;there were 12 cases in Meyerding I degree, 16 in II degree and 6 in III degree;28 patients had lower back pain associated with lower limb pain;19 patients had lower back pain associated with numbness of lower limb;18 patients had lower back pain associated with lower limb muscle weakness and 2 pa?tients had urination and defecation function disturbance. The surgical operation time, bleeding, postoperative drainage flow, graft fusion rate, complications were measured, and the intervertebral disc height, Japanese Orthopaedic Association (JOA), Oswestry disability indes (ODI), visual analogue scale (VAS) score were compared before and after treatment. Results The operation of 34 patients was successfully completed with the average operation time of 1.8 ± 0.8 h, and the bleeding in operation was 362.4 ± 93.7 ml, while postoperative drainage flow was 116.3±54.2 ml. All patients were effectively followed up for 12 months to 46 months (av?erage, one year and 10 months). Two weeks after operation, the intervertebral disc height were obviously increased (9.85±1.11 mm, 9.63 ± 1.04 mm), and there were significant difference compared with preoperative results (6.53 ± 0.98 mm, 6.24 ± 1.07 mm), but there were no significant difference compared with the latest follow?up results (9.23±1.33 mm, 9.30±1.16 mm). At the latest follow?up, JOA score was 13.19±1.08, ODI score 12.34±7.52, VAS score 2.23±1.51, and there were significantly different in each score compared with preoperative results. The symptoms of low back pain, lower limb nerve dysfunction and quality of life were signifi?cantly improved compared with preoperative situation. At the 16 month follow?up, all postoperative patients with vertebral body bone graft were judged to be fused. There was no pedicle screw loosening, fracture and so on. Conclusion Single rectangle cage interbody fusion combined with pedicle screw fixation for the treatment of isthmic spondylolisthesis is a kind of mini?invasive, less bleeding, safe and effective surgical method.

Objective:To explore the safety and effectiveness of the Renaissance spine surgery robot in the middle and upper thoracic spine fractures.Methods:62 patients with middle and upper thoracic vertebra fractures from March 2015 to March 2019 were prospectively analyzed. These patients were randomly divided into robot group (Renaissance robot-assisted nailing) and free hand group (unarmed nailing under perspective). There were 32 patients in robot group, including 25 males and 7 females with an average age of 43.1±8.91 years (range, 18-65 years). Body mass index (BMI) was 26.15±3.97 kg/m 2 (range, 16.3-41.7 kg/m 2). The preoperative Cobb angle was 20.9 °±2.83° (range, 10.7 °-33.9°). In the free hand group, there were 30 cases, including 24 males and 6 females; Age 44.2±9.10 years (range, 20-67 years), BMI 25.97±4.02 kg/m 2 (range, 17.1-43.2 kg/m 2); The preoperative Cobb angle was 21.3°±3.01° (range, 11.6°-35.1°). The 2 groups were compared in terms of accuracy of screw placement, one-time success rate of screw placement, completion time of screw placement, time of total operation and penetration rate of anterior vertebral margin. The robot group also compared the consistency of screw placement angle with preoperative planning. Results:All patients completed the operation successfully. The number of fractured vertebrae in the robot group was 37; the screw placement time was 16.11±5.82 min; the total number of screws was 230, of which 227 were successfully placed at one time, with a success rate of 98.70% (227/230); 1 screw was inserted through the anterior edge of the vertebral body, and the penetration rate was 0.43% (1/230). The number of fractured vertebrae in the free hand group was 35; the nail placement time was 21.09±7.31 min; the total number of screws was 216, of which 195 were successfully placed at one time, with a success rate of 90.28% (195/216); 12 screws was inserted through the anterior edge of the vertebral body, and the penetration rate was 5.56% (12/216). There were significant differences in the time, success rate and penetration rate between the two groups. There was no significant difference in the total operation time between the robot group and the unarmed nail group 137.23±12.68 min and 140.23±13.13 min, respectively. There was no significant difference in the angle of screw placement between pre-operative planning image and post-operative CT scan in the robot group.Conclusion:Renaissance spinal surgery robot in the treatment of middle and upper thoracic vertebra fractures has the advantages of high accuracy, low intraoperative risk, high safety and satisfactory effect of pedicle screw placement.