Iatrogenic nerve injury is one of the most severe complications of surgical correction for spinal deformity with different etiologies.The intraoperative neurophysiological monitoring (IONM) has been widely used to detect the nerve injury in spinal correction surgery.The commonly used IONM techniques involve somatosensory evoked potential (SEP),motor evoked potentials (MEP) and electromyography (EMG).All the IONM techniques have both advantages and disadvantages,while combing SEP,MEP and EMG in the spinal correction surgery could maximumly improve the accuracy and reliability of the IONM.The different pathophysiology of patients with spinal deformity due to different etiologies might significantly decrease the success rate,sensitivity,and specificity of IONM,which might further decrease the reliability of IONM.However,the IONM still serves as the most important monitoring method for the iatrogenic nerve injury in patients with different spinal deformity due to different etiologies.For those monitoring changes that cannot be distinguished,the wake-up test is still the gold standard.

Objective:To evaluate the radiographic and clinical outcomes of pre-operative Halo-gravity traction (HGT) and posterior correction surgery in treating patients with neurological deficits secondary to severe focal angular kyphosis of the upper thoracic spine.Methods:A total of 16 patients (11 males, 5 females) with neurologic deficits secondary to severe focal angular kyphosis of the upper thoracic spine undergoing preoperative HGT and posterior correction operation from January 2010 to December 2019 were retrospectively analyzed. The average age was 12.9±5.6 years (range 6-27 years). The standing X-ray of whole spine was taken at pre-, post-traction and post-operation. The Cobb angles of main curve at both sagittal and coronal planes were measured accordingly. The neurologic function at pre-traction, post-traction and post-operation was assessed according to the American Spinal Injury Association (ASIA) grading. The complications during HGT, operation and post-operative follow-up were recorded for each patient.Results:The average values of focal kyphosis and scoliosis were 96.1°±16.0° (71°-128°) and 75.5°±20.5° (40°-107°) at pre-traction respectively. The spinal cord function graded by ASIA criteria at pre-traction was B in 1 patient, C in 6 and D in 9, respectively. The correction rates of focal kyphosis and scoliosis were 32.8%±15.0% (18.0%-65.9%) and 22.9%±8.0% (14.1%-38.6%) after traction, which were further improved to 45.4%±14.9% (29.0%-69.0%) and 33.6%±8.6% (23.3%-49.3%) at post-operation without significant correction loss during 35.6±14.2 (24-72) months follow-up. After traction, the spinal cord function improved to grade D in 4 patients and grade E in 12 patients. At the last follow-up, the spinal cord functions were grade E in 15 patients and grade C in 1 patient. No neurologic monitor events occurred during operation. One patient suffered from transient left brachial plexus after operation. Further, proximal hook loosening was observed in 2 patients during follow-up. The spinal cord function was ASIA grade C pre-operatively in one patient, who recovered to ASIA grade E after operation and significantly deteriorated to ASIA C at 4 years follow-up.Conclusion:The correction of spinal kyphoscoliosis was satisfactory in this cohort. Preoperative HGT followed by posterior spinal correction surgery is an effective and safe procedure in treating neurological deficits secondary to focal angular kyphosis in the upper thoracic spine.

Objective To explore the feasibility and efficacy of posterior minimally invasive scoliosis surgery in Lenke 5C adolescent idiopathic scoliosis (AIS).Methods From November 2012 to March 2014,a total of 16 patients underwent posterior minimally invasive scoliosis surgery assisted by O-arm three-dimensional CT navigation were included.There were 14 female and 2 male,with an average age of (16.7± 1.6) years (ranged from 14 to 18 years).The mean Cobb angles of lumbar and thoracic curve were 48.7°±5.6°and 24.1°±5.4°,respectively.Results 16 patients were successfully completed the operation,the average operation time was (246±89) min,the average intraoperative blood loss was (192± 105) ml,and the fusion level was 4.9±0.5 on average.A total of 155 screws were inserted in the 16 patients,with a mean implant density of 98.9％±4.9％.All the patients were followed up for (26.4±3.9) months on average.The following radiographic parameters were evaluated before surgery,immediately after surgery and at the last follow-up:curve magnitude,apical vertebral translation (AVT),apical vertebral rotation (AVR),trunk shift,thoracic kyphosis (TK),thoracolumbar kyphosis (TLK),lumbar lordosis (LL) and sagittal vertical axis (SVA).The accuracy of pedicle screw placement was assessed according to postoperative CT scans.SRS-22 scores and complications were also recorded during the follow-up.Immediately after surgery,the correction rate of main lumbar curve was 80.1％±8.3％,and thoracic curve was 59.3％±8.7％,and a obvious improvement was noted in terms of AVT,AVR,trunk shift and TLK.At the last follow-up,except the increase of SVA from (-27.6± 19.5) mm to (-12.3±6.6) mm,no obvious changes of AVT,AVR,trunk shift,TK,TLK and LL were observed during the follow-up.According to CT evaluation,the satisfactory rate of pedicle screw placement was 94.2％,while the perforation rate was 5.8％ (9/155).Fusion across the facet joint were satisfactory.In SRS-22 assessment,the mean scores of functional,pain,self-image,mental state and satisfaction were (4.3 ± 0.5) points,(4.7 ± 0.6) points,(4.2 ± 0.7) points,(4.2 ± 0.5)points and (4.4 ± 0.6) points.No wound infection,implant failure and neurologic complications were found after surgery.Conclusion Wiltse approach assisted by O-arm three-dimensional CT navigation has the characteristics of small injury,less bleeding,high accuracy placement of pedicle screws and high self-satisfaction of patients.It is a feasible,safe and effective way to treat Lenke 5C AIS.

Objective To evaluate the effects of different levels of neuromuscular blockade(NMB)on transcranial electric motor-evoked potentials(TCeMEPs)during idiopathic scoliosis.Methods Thirty American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of both sexes,aged 11-23 yr,weighing 31-62 kg,scheduled for elective idiopathic scoliosis under general anesthesia,were enrolled in the study.NMB was monitored with train of four(TOF)-Watch SX.The levels of partial NMB were classified into 5 states according to TOF ratio(TOFR)and TOF counts:1 or 2 TOF counts(TOF1),3 TOF counts and TOFR≤15%(TOF2),TOFR 16%-25%(TOF3),TOFR 26%-50%(TOF4),TOFR 51%-75%(TOF5) and TOFR>75%(no NMB).Each state was maintained for 10 min.Failure and false-positive findings in TCeMEP monitoring,development of unexpected body movement and satisfaction with NMB were recorded.Results Compared with no NMB,the failure and false-positive rates of TCeMEP monitoring were significantly increased,the incidence of unexpected body movement was decreased,and the rate of satisfactory NMB was increased at TOF1,TOF2 and TOF3(P<0.05),no significant change was found in failure or false-positive rates of TCeMEP monitoring at TOF4 and TOF5(P>0.05),and the incidence of unexpected body movement was decreased and the rate of satisfactory NMB was increased at TOF4,the rate of satisfactory NMB was increased at TOF5(P<0.05),and no significant change was found in the incidence of unexpected body movement at TOF5(P>0.05).Compared with those at TOF4,no significant change was found in the failure or false-positive rates of TCeMEP monitoring(P>0.05),the incidence of unexpected body movement was significantly increased,and the rate of satisfactory NMB was decreased at TOF5(P<0.05).Conclusion Maintaining TOFR at 26%-50% the partial NMB during surgery does not affect TCeMEP monitoring during idiopathic scoliosis and meets the intra-operative NMB requirements simultaneously,and it is the optimum NMB for this type of surgery.

Objective: To illustrate the surgical strategy of sequential correction in degenerative lumbar scoliosis (DLS) with type C coronal imbalance, and to evaluate the clinical outcomes and advances of sequential correction technique. Methods: Twelve patients (2 males and 10 females) applying sequential correction technique from January 2015 to August 2017 were retrospectively reviewed. The ages of the cohort ranged 48-74 years and the average value was 52.3±8.4 years. The sequential correction technique was mainly applied in 3 steps: correction of local kyphoscoliosis with satellite rod on convex side of lumbar spine; correction of lumbosacral curve with L ₄-S₁ Intervertebral fusion and satellite rod on convex side of lumbosacral spine; correction of global deformity with bilateral long rods. The coronal parameters including Cobb angle and distance between C₇ plumb line and center sacral vertical line (C₇PL-CSVL), and the sagittal parameters including global kyphosis (GK) and sagittal vertical axis (SVA) were assessed at pre-operation, post-operationand last follow-up. The quality of life was evaluated using SF-36 questionnaire, and paired t test was used for the statistical analysis. Results: The average follow-up period was 16.7±4.8 months. The Cobb angles at pre-operation and post-operation were 59.6°±18.7° and 25.6°±12.4° (t=3.705, P<0.001), respectively. At last follow-up, the average Cobb angle was 27.5°±13.0°, and there was no significant loss of correction (t=0.366, P=0.718). Post-operative C₇PL-CSVL changed from 48.5±17.2 mm to 9.7±4.3 mm (t=5.842, P<0.001), of which the average value was 10.1±4.5 mm at last follow-up (t=0.223, P=0.826). At post-operation, 11 patients were with type A coronal imbalance, and 1 patient was still with type C coronal imbalance. The scores of bodily pain, general health, and social functioning were 8.4±1.9, 78.1±9.4 and 76.7±8.4 at pre-operation, 10.2±2.0 (t=2.260, P=0.034) , 89.5±7.6 (t=3.267, P=0.004) and 84.5±9.3 (t=2.156, P=0.042) at post-operation. In addition, there was no implant-related complications during follow-up. Conclusion The sequential correction technique could be well used in adult degenerative lumbar scoliosis patients with type C coronal imbalance, which can simplify the surgical procedure, decrease the rates of post-operative coronal imbalance, and obtain rigid internal fixation.

Objective: To investigate the efficacy and safety of Ponte osteotomy and sequential correction technique with satellite rod construction in the treatment of severe rigid thoracic scoliosis. Methods: A total of 32 patients (12 male, 20 female) with severe rigid thoracic scoliosis (Cobb angle>100°) who underwent posterior Ponte osteotomy and sequential correction technique with satellite rod construction between October 2012 and October 2016 and with more than 2 years follow-up were retrospectively reviewed. Major curve Cobb angle, apex vertebral translation, trunk shift, thoracic kyphosis and lumbar lordosis were measured through standing posterior-anterior X-ray preoperatively, postoperatively and at the final follow-up. The duration of operation, blood loss and complications were recorded. SRS-22 questionnaire was used to evaluate the clinical outcomes. Results: The average age was 21.3±10.8 years (range from 17 to 46 years). The mean preoperative major curve Cobb angle was 117.8°±9.8°(range from 104° to 131°) with a mean flexibility of 13.9% and the mean thoracic kyphosis was 65.5°±18.7° (range from 48° to 87°). The mean duration of operation was 267.4±42.3 min and the mean blood loss was 895.4±103.1 ml. The mean fused levels ranged from T2 to L4 with a mean 13.3±2.4 fused segments. The mean implant density was 62.1%±8.8%. Ponte osteotomy was performed in 4-9 segments which was 6.1±1.9 segments in average. The coronal main curve was corrected to 54.4°±10.9° with a mean correction rate of 53.9%±9.3% and the mean thoracic kyphosis was corrected to 35.6°±12.0°, which were both significantly improved. The average follow-up time was 34.3±8.9 months. At the last follow-up, the mean coronal main curve was 53.1°±1.9° with a mean correction loss of 1.3° and the thoracic kyphosis was 36.7°±11.4°. There were no neurological deficit or implant failure postoperatively and follow-up. Conclusion Ponte osteotomy followed by sequential correction technique with satellite rods construction was safe and effective which could achieve satisfactory correction rate and less correction loss during the longitudinal follow-up in the treatment of severe rigid thoracic scoliosis.

Objective:To modify the global alignment and proportion (GAP) score according to the spinopelvic alignment of healthy volunteers and to validate the reliability of the GAP score and the modified GAP (M-GAP) score in the prediction of mechanical failure after corrective surgeries in adult degenerative scoliosis (ADS).Methods:Clinical and radiographical data of 66 ADS patients undergoing correction surgeries in our center between January 2014 and January 2017 were retrospectively reviewed. The average age of the cohort was 60.2±7.1 years, including 13 male patients and 53 female patients. The predictive ability of GAP score to the mechanical failure was validated with Fisher's exact test and Linear-by-linear association test. Sagittal spinopelvic parameters were measured on lateral full-spine X-rays of 67 healthy volunteers aged between 50 and 70. The average age of these subjects was 58.2±5.4 years. Values of spinal and pelvic parameters including pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), global tilt (GT) and sagittal vertical axis (SVA) were measured. Simple linear regression analysis was conducted between PI and SS, LL and GT, respectively. The equations of regression analysis were used to calculate patients' ideal SS, LL and GT, and to establish the modified GAP (M-GAP) score. The predictive ability of M-GAP score to the mechanical failure was also validated.Results:Sagittal spinal and pelvic parameters of healthy subjects were measured and illustrated. The correlations between SS, LL and PI were SS=0.40×PI+12, LL=0.46×PI+22 and GT=0.46×PI-5. According to the GAP score, the postoperative sagittal spinopelvic alignment was proportioned in 16 (24.2%) cases, moderately disproportioned in 32 (48.5%) cases and severely disproportioned in 18 (27.3%) cases according to the original GAP score, and the occurrence of mechanical complication was 18.8% (3/16), 12.5% (4/32) and 22.2%(4/18) respectively. The GAP categories were not significantly correlated with the prevalence of mechanical failure ( P=0.633), and no significant linear correlation was found (χ 2=5.022, P=0.822). After re-evaluation of M-GAP score, the postoperative sagittal spinopelvic alignment was proportioned in 32 (48.5%) cases, moderately disproportioned in 25 (37.9%) cases and severely disproportioned in 9 (13.6%) cases, and the occurrence of mechanical failure was 6.3% (2/32), 24.0% (6/25) and 30%(3/9), respectively. The prevalence of mechanical failure was statistically different between proportioned, moderately disproportioned and severely disproportioned spinopelvic alignment patients classified by M-GAP score ( P=0.048), and there was a statistically significant linear association between the M-GAP categories and the occurrence of mechanical complications (χ 2=0.093, P=0.034). Conclusion:Poor predictive ability of the original GAP score to the mechanical failure was detected in ADS patients. However, the modified GAP score seemed to be a reliable predictor for mechanical failure in ADS patients.

Objective: To evaluate the efficiency of preoperative Halo-gravity traction (HGT) in the treatment of severe kyphoscoliosis secondary to neurofibromatosis type Ⅰ (NF1). Methods: A retrospective review was conducted on patients with severe kyphoscoliosis secondary to NF1 at Department of Spinal Surgery, Drum Tower Hospital, Medical School of Nanjing University between July 2007 and May 2016. A total of 29 patients including 17 males and 12 females were finally enrolled and the age was (13.7±2.9) years. The Cobb angle of major coronal curve and global kyphosis were measured before and after HGT. The forced vital capacity (FVC)and forced expiratory volume in 1 second (FEV₁) before and after traction were also recorded. The paired t test was used for comparison analysis. Results: The average maximum traction weight of HGT was (12.2±2.8) kg and the traction duration was (10.2±6.6) weeks. The coronal Cobb angle before HGT was (87.5±36.5)°, which improved to (68.4±25.9)° after HGT with a correction rate of (21.9±12.1)% (t=9.14, P<0.001); the average global kyphosis before HGT was (79.1±27.1)°, which improved to (59.9±19.4)° after HGT and the correction rate was (20.2±14.1)% (t=8.55, P<0.001). One patient had transient brachial plexus palsy which resolved completely after reducing the traction weight. After HGT treatment, FVC increased from (0.83±0.16) L to (0.89±0.19) L (t=1.48, P=0.12) and FEV₁ increased from (0.72±0.16) L to (0.78±0.20) L (t=0.49,P=0.63). FVC predicted and FEV₁ predicted improved from (42.9±20.1)% and (40.6±19.6)% to (46.9±20.5)% (t=0.98,P=0.33) and (43.6±25.8)% (t=1.24,P=0.22), respectively. Conclusion Preoperative HGT in the treatment of severe kyphoscoliosis secondary to NF1 can improve spinal deformity and pulmonary function to some extent, which can further benefit the patients by improving their surgical tolerance.

Objective: To evaluate the radiographic and clinical outcomes of Scoliosis Research Society(SRS)-Schwab Grade IV osteotomy in type I congenital kyphosis. Methods: All of 28 patients with type I congenital kyphosis who underwent SRS-Schwab Grade 4 osteotomy from June 2015 to June 2017 were retrospectively reviewed,including 21 males and 7 females aged 10 to 28 years old, with an average of 13.6±8.5 years. On standing wholespinal X-rays at pre-operation, post-operation and each follow-up, global kyphosis(GK), thoracic kyphosis(TK), lumbar lordosis(LL) and sagittal vertical axis(SVA) were measured. The intra-operative and post-operative complications were recorded for each patient. The Scoliosis Research Society-22 questionnaires(SRS-22) and visual analog scale(VAS) for back pain were collected from patients elder than 12 years old at pre-operation and last follow-up. The comparison analysiswasperformed by paired samples t test. Results: At pre-operation, the GK, TK, LL and SVA were 47.0°±4.9°, 16.8°±3.7°, 36.6°±7.7°, (-31.9±13.6) mm, respectively. At 3 months post-operation, the average values improved to 3.7°±2.3°, 36.8°±4.0°, 46.5°±4.4°, 4.0±19.1 mm, respectively. Significant differences were found in all parametersbetween pre- and post-operation. The post-operative follow-up was 12 to 24 months, with an average of 13.2±5.2 months. At the last follow-up, the GK, TK, LL and SVA were 4.0°±2.4°, 38.0°±6.0°, 45.9°±5.4°, 7.6±15.3 mm, and no significant correction loss was found during follow-up. The scores of each domain of SRS-22 questionnaire improved at different level during follow-up, of which the improvement in self-imagewas statistically significant (P<0.001). The scores of VAS for back pain improved significantly after operation (P<0.001). One patient hadabnormal intra-operative monitoringwhile no neurological defectwas detected at post-opera tion. Proximal junctional kyphosis occurred in 2 patients at 3 months follow-up while no patients needed revision surgery. There wereno implant-related complicationsduring follow-up. Conclusion The SRS-Schwab Grade 4 osteotomycould provide satisfying correction with relatively low rates of complications in type I congenital kyphosis. Thus, the SRS-Schwab Grade IV osteotomy is a safe strategy for type I congenital kyphosis.

Objective To investigate the incidence and risk factors for rod fracture after correction surgery with satellite rod in severe spinal deformity.Methods A retrospective analysis was made including 234 cases who underwent correction surgery using satellite rod technique for severe spinal deformity in our hospital from July 2012 to June 2017.At the last follow-up,a total of 6 patients were found to have rod fracture.All the patients had complete clinical and imaging data at the time of preoperation,postoperation,rod fracture occurring,post-revision and the last follow-up.The Cobb angle,the Global kyphosis (GK),the coronal balance (distance between C7 plumb line and center sacral vertical line,C7PL-CSVL) and the sagittal vertical axis (SVA) were measured respectively in the 6 patients with rod fracture during the follow-up process.The time,incidence and position of the broken rod were recorded,and the reasons of rod fracture were analyzed for each patient.Results The incidence of rod fracture was 2.6％ (6/234) in the current study.The 6 patients included 3 males and 3 females with an average age of 34.5±15.4 years at initial surgery.The mean time of rod fracture was 24.0±17.7 months,of which 3 cases (50％) occurred within 1 years after operation.A total of 7 rods were broken,including 4 (57％) rods located at the single-rod-fixed side with stress concentration and 3 (50％) rods at the adjacent segment of the satellite rod.The average loss of correction was 20.8°±29.4° for Cobb angle and 34.0°±21.4° for GK.The potential reasons for rod fracture were listed as follows:3 cases for residual kyphosis;2 cases for pseudarthrosis;3 cases for long fusion construct crossing lumbosacral junction;1 case for trauma.Of the 6 patients with rod fracture,3 (43％) patients underwent revision surgery by replacing the broken rods,adding satellite rod at the opposite side of pre-existing satellite rod and bone graft at the rod-breakage area.The other 3 patients underwent observation and no deterioration was found during follow-up.Conclusion The incidence of rod fracture after correction for severe spinal deformity with satellite rod is 2.6％.The broken rods are mainly located at the single-rod-fixed side with stress concentration or the adjacent segment of the satellite rod.Residual kyphosis,pseudarthrosis,long fusion construct crossing lumbosacral junction and trauma are the significant risk factors of rod fracture.