BACKGROUND:Pedicle screw is the major instrumentation of surgery in thoracic spine. However, there have been few reports about pedicle morphology relevant to screw insertion tracts, and few reports comparing the normal adolescents and adolescent idiopathic scoliosis patients. OBJECTIVE:To compare the morphologic characteristics of the thoracic pedicle with regard to safe thoracic pedicle screw placement in normal adolescents and adolescent idiopathic scoliosis patients. METHODS: Thoracic pedicles of thirty-five normal adolescents and thirty-five adolescent idiopathic scoliosis patients were measured with three-dimensional reconstruction CT images. Measured parameters include (1) critical distance: the shortest distance from an entry point to the ventral cortex of the lamina. (2) Safe distance: the distance from the entry point to the tangent of the spinal canal at the medial wal of the pedicle. (3) Pedicle screw length. (4) Pedicle width. (5) Pedicle transverse angle. The dangerous area was defined as the distance between the critical distance and the safe distance. RESULTS AND CONCLUSION: The mean critical distance was (9.2±1.0) mm for the normal adolescents, and (9.4±1.2) mm for the adolescent idiopathic scoliosis patients. Safe distances were significantly less in normal adolescents (14.7±0.8) mm than that of the adolescent idiopathic scoliosis group (15.4±1.4) mm (P < 0.001). The dangerous area was (5.4±0.7) mm for the normal adolescents, which was significantly less than that of the adolescent idiopathic scoliosis patients (6.0±1.0) mm (P < 0.001). Pedicle screw length was (36.6±4.1) mm for the normal adolescents and (37.1±5.3) mm for the adolescent idiopathic scoliosis patients. Pedicle width was (5.8±1.2) mm for the normal adolescents and (5.7±1.7) mm for the adolescent idiopathic scoliosis patients. No significant difference in critical distance, pedicle screw length and pedicle width was found between the two groups (P=0.382, 0.135, 0.293). Pedicle transverse angle decreased gradualy from T1 to T12 in both groups. These results verify that pedicle morphology of many parameters is different between normal adolescents and adolescent idiopathic scoliosis patients, especialy in the apical area of the thoracic curve.

Objective To discuss the short-term currative effect of horizontal osteotomy across injured vertebral forⅤdegree old frac-ture-dislocations of thoracolumbar spine.Methods The data of 4 patients who received horizontal osteotomy across injured vertebral internal fixation in our hospital from April 2010 to October 2012 were retrospectively analyzed,of which 1 case with T8-9 fracture dislocation,2 cases with T10-11 fracture dislocation,1 case with T11-12 fracture dislocation.The Franke1 classification of all patients were grade A.Results All 4 cases were achieved completely fracture reduction and followed-up for 2-14 months(an average of 7.4 months),who could get sitting posi-tion with the support of brace 1 week after operation.The postoperative follow-up indicated that all 4 cases got fusion,but there was no improve-ment for Franke1 classification.Conclusion The method of horizontal osteotomy across injured vertebral forⅤdegree old fracture-dislocations of thoracolumbar spine has good short-term clinical effect,with the advantages of shorter operation time,less bleeding and good reduction effect.

Objective: To compare the clinical effects of robot-assisted minimally invasive transforaminal lumbar interbody fusion (TLIF) and traditional open TLIF in the treatment of lumbar spondylolisthesis. Methods: A total of 41 patients with lumbar spondylolisthesis accepted surgical treatment in Department of Spinal Surgery of Beijing Jishuitan Hospital From July 2015 to April 2016 were retrospectively analyzed. There were 16 cases accepted robot-assisted minimally invasive TLIF and 25 accepted traditional open TLIF. The operation time, X-ray radiation exposure time, perioperative bleeding, drainage volume, time of hospitalization, time for pain relief, time for ambulatory recovery, visual analogue scale (VAS), Oswestry disability index (ODI) and complications were compared. T test and χ² were used to analyze data. Results: There were no significant difference in gender, age, numbers, degrees, pre-operative VAS and ODI in spondylolisthesis (all P>0.05). Compared with traditional open TLIF group, the robot-assisted minimally invasive TLIF group had less perioperative bleeding ((187.5±18.4) ml vs. (332.1±23.5) ml), less drainage volume ((103.1±15.6) ml vs. (261.3±19.8) ml), shorter hospitalization ((7.8±1.9) days vs. (10.0±1.6) days), shorter time for pain relief ((2.8±1.0) days vs. (5.2±1.1) days), shorter time for ambulatory recovery ((1.7±0.9) days vs. (2.9±1.3) days) and less VAS of the third day postoperatively (2.2±0.9 vs. 4.2±2.4) (t=2.762-16.738, all P<0.05), but need more operation time ((151.3±12.3) minutes vs. (102.2±7.1) minutes) and more X-ray radiation exposure ((26.1±3.3) seconds vs. (5.5±2.1) seconds) (t=6.125, 15.168, both P<0.01). In both groups ODI was significantly lower in final follow-up than that of the pre-operation (t=12.215, 14.036, P<0.01). Intervertebral disc height of the final follow-up in both groups were significantly larger than that of the preoperation (robot-assisted minimally invasive TLIF group: (11.8 ± 2.8) mm vs. (7.5 ± 1.9) mm, traditional open TLIF group: (12.7 ± 2.5) mm vs. (7.9±2.0) mm), and so was the lumbar lordosis angle (robot-assisted minimally invasive TLIF group: (48.7±9.2)°vs. (39.6±7.9)°, traditional open TLIF group: (50.1±10.8)°vs. (41.4±8.8)°), the lordosis angle of the slippage segment (robot-assisted minimally invasive TLIF group: (18.7±5.6)°vs. (10.9±3.8)°, traditional open TLIF group: (17.6±6.1)°vs.(8.7±3.2)°) (t=4.128-16.738, all P<0.01). Slippage rate of the final follow-up in both groups were significantly smaller than those of the pre-operation (robot-assisted minimally invasive TLIF group: (5.3±2.3) % vs. (27.8±7.2) %, traditional open TLIF group: (6.6±2.8) % vs. (29.1±9.5) %) (t=11.410, 18.504, both P<0.01). There was no difference of the upper data between two groups (t=0.106-1.227, P>0.05). The results of the post-operative CT showed that the pedicle screws in the robot-assisted minimally invasive TLIF group were more precisely placed than traditional open TLIF group (χ²=4.247, P=0.039). The mean follow-up time was 8 months (ranging from 3 to 12 months). There were no significant difference in outcomes between the two groups (χ²=0.366, P=0.545). Conclusions In the treatment of lumbar spondylolisthesis, Robot-assisted minimally invasive TLIF can lead to less perioperative bleeding, less post-operative pain, and quicker recovery than traditional open TLIF surgery, but it needs more operation time and radiation exposure.