The etiology of adolescent idiopathic scoliosis ( AIS) ,the most common form of scoliosis, is still unclear.This article reviews the progress of etiology and related problems of AIS from the points of genetic factors, growing development, hormone metabolism and nervous dysfunction.

Objective To explore the pathogenesis of the superior mesenteric artery syndrome (SMAS) after surgical correction of scoliosis, and to analyse the inducing factors of the SMAS during scoliosis correction. Methods From July 1997 to January 2001, 430 cases of scoliosis were corrected with the 3 dimensional derotation technique(312 cases of the CD instrumentation and 118 cases of the TSRH or CDH instrumentation), 5 cases of which suffered from the SMAS postoperatively. Three of these 5 cases had the SMAS during the heavy Halo-pelvic traction following the anterior spinal release, the other two cases happened after the posterior correction. Results For the 5 patients, the symptoms were relieved after fasting,drainage with nasogastric tube, keeping electrolytic balance, left lateral position, suspense or reduction of the heavy traction, all of them recovered completely after 5-7 days. Conclusion SMAS is apt to occur in severe scoliosis, especially in kyphoscoliosis with trunk collapse. If more spine elongation and higher correction rate are obtained during operation, or the heavy Halo-pelvic traction is necessary after the anterior spinal release, the SMAS is more likely to happen. Early diagnosis and treatment play an important role in the recovery of patients.

Objective To evaluate the clinical manifestation and the treatment strategy of the scoliosis associated with Chiari malformation and /or syringomyelia. Methods Fifty-two cases suffered from scoliosis with Chiari malformation and /or syringomyelia were divided into three groups for surgical treatment: 1) Group 1: 18 cases had scoliosis with Chiari Ⅰmalformation and /or syringomyelia without obvious neurologic impairment, their scoliosis was corrected with posterior instrumentation, but their Chiari Ⅰmalformation and syringomyelia were left untreated surgically. 2) Group 2: 12 patients, whose scoliosis was not indicated for surgery but those Chiari malformation associated with syringomyelia, underwent posterior sub-occipital craniectomy to enlarge foramen occipital magnum, C1 posterior arch decompression, duraplasty and syrinx-subarachnoid space shunting no matter whether neurologic deficits were present or not. 3) Group 3: 22 cases in addition of correction of scoliosis, due to neurologic deficits caused by Chiari Ⅰmalformation or syringomyelia, two-stage surgery was indicated: firstly, with posterior suboccipital craniectomy to enlarge foramen occipital magnum, C1 posterior arch decompression, duraplasty and syrinx-subarachnoid space shunting 6 months later, then underwent the scoliosis correction with instrumentation. Results In 34 patients who underwent craniovertebral decompression, only 6 of the 24 cases with preoperatively neurologic deficits achieved mild improvement within 6 months postoperatively. In 40 patients who were treated with posterior correction for scoliosis, the average frontal correction was 63% and the average sagittal correction was 80% for scoliosis less than 90?, the average frontal correction was 49% and the average sagittal correction was 74% for scoliosis more than 90?. At a follow-up of 6 months to 5 years, the average loss of the frontal correction was 6%. Conclusion Scoliosis associated with Chiari malformation and /or syringomyelia can be effectively treated with the similar results, as for adolescent idiopathic scoliosis. The mainstay for diagnosis is MR imaging. Accurate diagnosis and proper treatment for Chiari malformation or syringomyelia before scoliosis surgery will improve the rate of scoliosis correction, decrease the neurological complications.

Objective To evaluate the biomechanical basis and long term clinical outcome of the offset hook-screw combined instrumentation in preventing against correction loss after it is used to treat the unstable thoracolumbar fractures. Methods Of 98 cases treated with the offset hook-screw combined instrumentation from July 1997 to December 2002, 64 with follow-up over two years were reviewed. All 64 cases received operation within average 3.2 days after injury, of which 41 were fixated with CD or CD-Horizon instrumentation and 23 with TSRH instrumentation. The long term clinical outcome evaluation included the maintenance of the vertebral height restoration, the sagittal kyphotic Cobb angle loss and the coronal Cobb angle correction loss. Results No death occurred. But after operation, there was one case with worsened neurological deficits (recovered one week after surgery) and two with deep infection. The average post-operative vertebral height and the coronal Cobb angle were restored by 89.0% and 100.0% respectively and the sagittal kyphotic Cobb angle corrected from preoperative 31?to postoperative -1? . During the follow-up for 24-62 months, no instrumentation breakage occurred. The pseudoarthrosis was affirmed in one case and suspected in two with the vertebral height loss of 8.6% and the kyphotic Cobb angle correction loss of 4?respectively. Conclusions The offset hook-screw combined instrumentation can satisfactorily restore the normal sagittal profile, effectively prevent the fixation loosening or breakage, minimize the mechanical failure of instrumentation, and particularly reduce the loss of long-term correction.

35? in 40. Risser sign was 0 in 38,Ⅰin 19,Ⅱin 13, and Ⅲ in 7. The standing AP X-ray films were obtained at intervals of 3 to 6 months. The Cobb's angle, the apical vertebral rotation and the Risser sign were measured at initial brace application and at the latest follow-up. Results With a follow-up of 24 to 60 months (mean, 30 months), 23 patients (29.9%) were judged as curve progression. Patients with double major curve were found to have the lowest percentage of curve progression, but there was no significant difference compared with other patterns of curves. The lower the Risser sign, the higher the initial brace correction rate and the percentage of curve progression. The difference of the initial brace correction rate was significant(P35?(P35?. 21 patients required surgical correction before completing bracing treatment because of curve progression, but in 13 of them, the surgical intervention was postponed about 12-20 months. Conclusion The Risser sign is a good predictor of bracing effect. Patients with double major curve have the lowest rate of treatment failure. The greater the amount of the Cobb's angle, the higher the percentage of curve progression. Bracing should be considered as successful if it can effectively reduce curve progression and postpone surgery.

Objective To investigate the clinical outcome of intermittent distracting rod for the correction of juvenile scoliosis, and analyze its complications. Methods Between July 1997 through June 2002, 21 patients with scoliosis underwent posterior growing-rod instrumentation, with their age ranged from 6 to 11 years. Risser sign was 0 in all patients. Average curve magnitude was 78 degrees (62 to 94 degrees) before initial instrumentation. A pair of claw-type hooks were inserted at the upper and lower levels respectively, one rod was attached to the upper hooks and the other to the lower hooks. These two rods were allowed to overlap and were connected with a growth connector. Distraction was achieved by means of lengthening the two rods at the connector site. Repetition of lengthening was indicated by the curve deterioration larger than 15 degrees or the interval of 10 to 12 months after the previous operation. After each operation, a Milwaukee brace was worn for external support. Results The initial intraoperative correction averaged 40 degrees, but this decreased to 23 degrees of correction on average at every subsequent lengthening. The total distraction procedure of 4 times only achieved in 5 patients. The reasons for distraction ceasing were as follows: hook dislodgment in 3 patients, looseness of pedicle screw in 2, looseness of dominos connector in 2, wound infection in 1, spontaneous fusion in 2, and insufficient financial support in 6. Conclusion Curve response to correction tends to decline with consecutive distractions. A high rate of complications has been noted during the distraction procedure. The single distracting rod technique is not suitable for the correction of severe scoliosis in Chinese children.

AIS group or NS group. 2)Cross sectional area of type Ⅰ fibers on the convex side: SS group

[Objective]To demonstrate the shift of the spinal cord to the concave side of the spinal canal in adolescent patients with idiopathic thoracic scoliosis,to investigate possible cause of the shift of the spinal cord and to explore its clinical relevance.[Method]Thirty-nine adolescents with idiopathic thoracic scoliosis were recruited in this study.Cobb's angle,relative apical translation and relative trunk shift of the major thoracic curves were recorded from standing posteroanterior roentgenography of the whole spine.The shift of the spinal cord was determined through the measurements of distance between the spinal cord and the medial walls of the pedicles on the convex and concave sides,which were performed in transverse magnetic resonance images of the spinal canal in the major thoracic curves(T5~12).The variations of the shift of the spinal cord were determined,and the relationships between the shift of the spinal cord at the apical region and Cobb's angle,and between that and the relative apical vertebral translation were analyzed.[Result]In the region of the major thoracic curves,the distance from the spinal cord to the pedicle on the convex side was significantly less than the distance to the pedicle on the concave side(P

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

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.