0.05).But there was a significant statistical difference among those parameters between Group A and Group B at final follow up(P

BACKGROUND:Previous studies have mainly focused on costal cartilage, articular cartilage, nasal septal cartilage, and auricular cartilage, but in vitro culture of human vertebral endplate cartilage is stil rarely reported. OBJECTIVE: To discuss the feasibility of culture of vertebral endplate chondrocytes from type I neurofibromatosis associated with scoliosis patientsin vitro and to study the biological characters of the chondrocytes. METHODS: Through two-step enzymatic digestion and tissue culture, the chondrocytes from the vertebral endplate of seven type I neurofibromatosis patients isolated and cultured in monolayer and passaged to observe the changes of cel morphology under inverted phase contrast microscope. Colagen type II expression was detected by immunocytochemistry to identify whether the cels had chondrocyte characters. The growth kinetics was detected by using MTT colorimetric assay to draw the growth curve of passage 2 chondrocytes. RESULTS AND CONCLUSION:A few chondrocytes crawled from the cartilage after 2 weeks culture and cels were passaged at 3 weeks. Along with passage going on, the phenotype of chondrocytes was changed from polygonal, round, triangle, and irregular shapes to fusiform. The colagen type II expression in passage 2 cels was positive by immunohistochemical staining. MTT test showed the growth curve of the passage 2 chondrocytes presented a transverse “S”. Cels were found logarithmic growth at days 4-7, reached platform stage at days 8-13, and decreased at day 14. It is an effective and simple procedure by two-step enzymatic digestion and tissue explant method to culture vertebral endplate chondrocytes with high purity and good viability from type I neurofibromatosis patients associated with scoliosisin vitro. Passage 2 chondrocytes from the vertebral endplate exhibit the best viability at days 4-7, which can be used as targets for research of pathogenesis of type I neurofibromatosis with atrophic scoliosis.

Objective To investigate the risk factors and revision strategies for rod fracture in patients with severe kyphoscoliosis following posterior vertebral column resection (PVCR).Methods Between June 2003 and June 2011,7 patients (4 males and 3 females) who developed rod fractures following PVCR in our institution were retrospectively reviewed.The average age was 24.4 years (range,12-39 years) at the time of primary surgeries.The occurrence times and locations of the rod fractures were recorded and the risk factors for the fractures were analyzed.Results The occurrence times of the rod fractures ranged from 6 to 53 months.Five cases of fracture occurred within 2 years after the primary surgeries,while the other 2 cases occurred more than 4 years after the primary surgeries.Six cases of fracture occurred at levels of osteotomies and 1 case occurred at 1 level below the osteotomy.The potential reasons for rod fractures were listed as follows:(1)residual kyphosis (1 case); (2) residual kyphosis combined with unsteady gait (1 case); (3) residual kyphosis combined with single rod fixation (1 case); (4) residual kyphosis combined with malposition of titanium mesh cage (1 case); (5) residual kyphosis combined with anterior column defect; (6) injury (2 cases).Six patients underwent revision surgeries,5 patients received one-stage combined anterior-posterior approach surgeries,while 1 patient received single posterior surgery.They were followed up for 12 to 22 months (average,18months).At final follow-up,all patients obtained satisfying corrections and graft fusion,without internal fixationrelated complications.Conclusion Rod fractures mostly occur at levels of osteotomies within 2 years after PVCR.Residual kyphosis is the main risk factor for the rod fracture.Injury,anterior column defects,unsteady gait,single rod fixation and malposition of titanium mesh cage also increase risks of rod fractures.

Objective To prospectively explore the techniques and correction results of the method of vertebral coplanar alignment (VCA) in posterior correction for thoracic scoliosis. Methods Between June 2008 to March 2009, 27 patients with idiopathic thoracic scoliosis were selected to undergo posterior pedicle screw fixation with assistance of Coplanar system. There were 26 females and 1 male with the average age of 15.9 years(ranged 11-23 years). There were type 1 in 25 cases and type 2 in two cases. The levels of fusion were established according to the Lenke criteria. The average preoperative coronal Cobb angle was 49°(ranged 40°-70° ). During the procedure, the pedicle screws were inserted in each involved levels on the convex side, an extended Coplanar tube was screwed in line with screw axis to each screws. Then two rigid bars were inserted through the uppermost part of the slotted tube sequentially. As the bar was gently driven down toward the bottom end, the pedicle screws axis started to converge in the straight line, correcting translation and rotation. Spacers were inserted into the slots of the tubes to achieve the ideal physiologic thoracic kyphosis. Once the rod was fixated in the concave side of the main curve, the Coplanar system could be removed. Results The mean postoperative Cobb angle was 14° (ranged 6°-25°), representing the correction rate of 70.7%. The average duration of surgery was 245 min (ranged 210-300 min) and a mean estimated blood loss was 1500 ml (ranged 600-2100 ml). The duration of follow-up averaged 15 (12-18) months. The loss of correction at last follow-up was 3° with the loss of correction rate of 6.1%. In the sagittal plane, the thoracic kyphosis was restored from 18° to 25°. No coronal or sagittal plane decompensation occurred. No thoraeoplasties were necessary to correct the residual rib hump. There was no death, infection and neurological complications. Conclusion The Coplanar is a new technique for the correction of scoliosis, its advantage lies in excellent and modulatable three-dimensional correction with a single and standardized maneuver.

Objective To analyze the influence of the Risser sign on the sagittal compensatory mode of the spine in idiopathic thoracic scoliosis after anterior spinal fusion.Methods Between June 2002 and November 2006,43 adolescent idiopathic scoliosis(AIS)patients(Lenke 1)undergone anterior correction with a minimum 2 years follow-up were included in this study.The patients were divided into three groups according to the Risser sign:group A(Risser 0),group B(Risser 1-3),and group C(Risser 4-5).The preoperative,postoperative and follow-up sagittal profile were evaluated by the following radiological parameters measured on the lateral radiograph,including the thoracic kyphosis,the lumbar lordosis,the thoracolumbar junction kyphosis,the distal junctional kyphosis,and the sagittal vertical axis.Results In group A,the thoracolumbar junction kyphosis significantly changed from-1.7° preoperative to 6.6° at the final follow-up,with an average increase of 8.3°.Similarly,in group B,the thoracolumbar junction kyphosis changed from -7.3° before surgery to 0.6° at the final follow-up,with an average variation of 7.9°.No obvious change of the thoracolumbar junction kyphosis was observed in group C.At the final follow-up,the average thoracic kyphosis in three groups was 21.2°,18.4° and 14.7°,respectively.No significance of the variation of the thoracic kyphosis was observed in the three groups,however,in group A and B,the thoracic kyphosis showed an ascending trend during the follow-up without significant statistical difference,in addition; the ratio of the thoracic kyphosis increased in group A was higher compared with group B and C.Conclusion For AIS patients with low Risser sign,the increased thoracic kyphosis,and the thoracolumbar junction kyphosis may be ascribed to the decompensation of thoracolumbar region caused by the reconstruction of sagittal alignment due to the continued growth of posterior elements of the thoracic spine.

Objective To compare the clinical and radiological outcomes between hybrid and total pedicle screw instrumentation in adolescents undergone posterior spinal fusion (PSF) for thoracic scoliosis secondary to Chiari malformation..Methods A total of 75 patients undergone PSF were included and divided into two groups:the all pedicle screw group (Group A,n=44) and the hybrid group (Group B,n=31).Patients were evaluated before surgery,immediately after surgery,and at the 2-year follow-up in radiographic changes in curve magnitude,apical vertebral translation (AVT),apical vertebral rotation (AVR),trunk shift,thoracic kyphosis (TK),lumbar lordosis (LL),and sagittal vertical axis (SVA).These parameters were further analyzed with respect to preoperative TK in both groups.Results After surgery,the average correction of the thoracic curve was 60.2％ and 51.3％ in Group A and B,respectively (t=2.372,P=0.023).The average lumbar curve correction was 61.7％ in Group A,representing a significant increase compared to Group B (51.1％,t=2.431,P=0.020).At the final follow-up,loss of the thoracic curve correction was less in Group A (0.3％) than in Group B (1.7％),however,there was no statistical significance (t=-0.468,P＞0.05).AVT of the thoracic curve improved in Group A from 25.0 mm to 6.9 mm,while in Group B it changed from 24.1 mm to 7.4 mm.For patients with a preoperative TK greater than 40°,the proximal junctional angle was found to be significantly larger in Group A (10.0 degrees versus 4.5 degrees,t=-2.031,P=0.052) by the final follow-up,along with a significantly increased incidence of proximal junctional kyphosis (20％ versus 9％).Conclusion Total pedicle screw instrumentation provided a significantly better correction of the major and minor curves than hybrid constructs for the operative treatment of thoracic scoliosis secondary to Chiari malformation.However,for patients with thoracic hyperkyphosis,all-screw instrumentation had a higher risk of adjacent level proximal kyphosis.

Objective To investigate the preoperative evaluation of pulmonary function and protocol for scoliotic patients with respiratory failure. Methods From September 2000 to June 2008, sixteen patients suffered from respiratory failure were recruited into this study. There were two males and three females who were diagnosed as idiopathic scoliosis with a mean age of 13.5 years (range, 10-16 years). The other eleven patients were diagnosed as congenital scoliosis, including five males and six females with a mean age of 12.4 years (range, 10-14 years). The mean preoperative Cobb angle was 126.6°±15.5° with a mean height of 137.6 cm (range, 120-160 cm) and a mean weight of 32.5 kg (range, 18-40 kg). Decision was made depending on the severity of pulmonary impairment and spinal deformity. Preoperative treatment included respiratory training, noninvasive positive pressure ventilation therapy and halo-gravity traction. Results All patients received corrective surgery; ten patients were extubated tracheal tubes successfully 1 hour after surgery and six patients had to stay in intensive care unit (ICU) for 24 hours. Pulmonaryedema occurred in two cases and pneumonia in one case. The Cobb angle had improved to 72.0°±13.2° after surgery with a correction rate of 43%. All patients recovered well after surgery with no major cardiac or pulmonary complications.Conclusion Patients with preexisting respiratory failure can tolerate deformity correction operation with few complications after receiving a set of preoperative respiratory training modalities.

Objective To investigate anterior longitudinal ligaments (ALL) ossified surrounding osteotomy vertebra impact the lordosing effect of pedicle subtraction osteotomy (PSO) in patients with thoracolumbar kyphosis secondary to ankylosing spondylitis (AS).Methods We retrospectively reviewed 102 AS patients with thoracolumbar kyphosis treated with single-level PSO at our institution from September 2007 to August 2015.There were 92 male and 10 female.The average age was (35.6±11.8)years old (range from 17 to 65 years old).Patients were stratified into ossified group (54 cases) and non-ossified group (48 cases)based on the presence of ALL ossification adjacent to osteotomy vertebra.Compared the contribution of adjacent disc wedging to total correction of each PSO segment between the ossified and non-ossified groups.The long-term correction loss of spine and pelvic sagittal morphology were also evaluated and compared between the 2 groups.Results Patients in the ossified group accomplished significantly lower amount of correction in single level segment of PSO (36.3°±6.9° vs.41.5°±6.9°),and there was significant difference between the two groups.The contribution of adjacent disc wedging to total correction of PSO was significantly larger in the non-ossified group (22.9％ vs.7.8％,P＜0.001).For subgroups with a minimum 2 year follow-up,loss of corrections concerned sagittal vertical axis (SVA),which was (1.7±4.5) cm vs.(-0.2±4.0) cm in ossified group and non-ossified group,and there was significant difference between the two groups.Pelvic tilt (PT) was 3.5°±8.2° vs.2.0°± 10.4°,lumbar lordosis (LL) was-7.9°±11.9° vs.-0.1°± 11.9° and sacral slope (SS) was 4.5°±9.3° vs.1.6°±7.9°,and there were all significant differences between the two groups.The change of adjacent disc wedging angle was marginally higher in the unossified group (-2.1°±6.2° vs.-0.1°±3.7°,P=0.09),but there was no significant difference between the two groups.No significant correction loss of osteotomy angle was observed in both groups.Conclusion Osteotomy vertebrae accompanied by unossified adjacent ALL in PSO of AS were prone to create more disc-originated lordosing effect immediately after surgery.However,a correction loss might occur more commonly during a long term follow-up.

ObjectiveTo explore the change of spino-pelvic parameters following pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis secondary to ankylosing spondylitis(AS).MethodsTwenty-one AS patients with thoracolumbar kyphosis,who underwent PSO at L1 level from July 2006 to October 2010 in our hospital,were retrospectively reviewed.There were 18 males and 3 females with a mean age of 35.6 years (range,21-53 years).The pre- and post-operative thoracic kyphosis(TK),lumbar lordosis (LL),globe kyphosis (GK),angle of the fusion levels (AFL),sagittal imbalance (SVA),pelvic incidence (PI),sacral slope (SS) and pelvic tilting (PT) were measured.ResultsSignificant differences were observed in terms of the improvement of LL,PT,SS,SVA,GK and AFL (P＜ 0.01).The alteration of LL showed significant correlation with the change of PT (r=0.59,P=0.005),SS (r=0.64,P=0.002),SVA (r=0.49,P=0.025),and AFL (r=0.60,P=0.004).The change of PT exhibited cardinal correlation with the change of SS(r=0.94,P=0.000).The improvement of AFL significantly correlated with the improvement of SS(r=0.61,P=0.003),PT (r=0.59,P=0.005).ConclusionThe change of the sagittal spino-pelvic profile following PSO in AS-related thoracolumbar kyphosis is closely related with the improvement of LL.

Objective To evaluate the potential risk of aorta injury by simulating different lateral misplacement patterns of thoracic pedicle screws (TPS) in the treatment of adolescent idiopathic scoliosis (AIS).Methods From December 2010 to August 2011,50 AIS patients were admitted to our hospital,including 7 males and 43 females,aged from 13 to 18 years (average,15.3±2.6 years).All patients underwent axial magnetic resonance imaging (MRI) scans from T5 to T12.The left pedicle-aorta (LtP-Ao) angle and distance were measured on the axial MR images by the software of PACS Client.The lateral misplacement of pedicle screw was simulated with variable direction errors (10°,20°,30°) and different lengths of pedicle screw (30 mm,35 mm,40 mm).A total of nine patterns of lateral pedicle screw misplacement were set up,and a warning misplacement was defined as the mimic pedicle screw crossed the aorta.The percentages of warning misplacement were compared in each pattern of lateral pedicle screw misplacement and each level from T5 to T12.Correlation analysis was made between the percentages of warning misplacement and the direction errors as well as length of pedicle screw.Results The mean LtP-Ao angle increased from 34.3°±8.5° at T5 level to 45.7°±4.1° at T7 level,and then gradually decreased to 9.2°±5.6° at T12 level.The mean LtP-Ao distance increased from 28.2±7.3 mm at T5 level to 37.7±6.5 mm at T12 level.The percentages of warning misplacement were positive correlation with the direction errors and length of pedicle screw.The percentage of warning misplacement was higher at the T11 level.Conclusion The potential risk of aorta injury increases with enlarging of direction error and lengthening of thoracic pedicle screw,particularly at the T11 level.