Three-dimensional finite element simulation of surgical correction for Lenke 2 type adolescent idiopathic scoliosis / 第二军医大学学报

Objective To simulate different anterior and posterior correction strategies using finite element model of Lenke 2 type adolescent idiopathic scoliosis (AIS), in an effort to seek the optimal surgical protocol. Methods The finite element model of Lenke 2 type AIS was established and used to simulate five surgical strategies. The effectiveness and shoulder balance parameters were compared among different surgical approaches. Results The coronary proximal thoracic (PT) Cobb angle and corrective rates of the five surgical strategies were 21. 5(44. 8%), 26. 5(32. 1%), 28. 1(27. 9%), 34. 1(12. 5%), and 32(17. 9%). The corrective rates for the main thoracic curves were not significantly different among the five strategies, and the physiological sagittal configuration was maintained. Postoperative radiographic shoulder balance parameters were increased for all five surgical protocols. Except for strategy A (posterior fusion from T2 to Tn), other four strategy achieved the following outcomes: coracoid height differences* 9 mm, clavical angle>2. 5° and clavicular tilt angle differences* 4. 5°. Conclusion Simulation of posterior correction and fusion to T2 including both thoracic curve can achieve excellent three-dimensional corrective results and balanced shoulders for Lenke 2 type AIS model with preoperative left elevated shoulder. Partial fusion of PT curves to T3 or T4 results in inferior corrective rate of PT curve and mild or moderate shoulder imbalance. Simulation of anterior or posterior selective main thoracic curve fusion has very low spontaneous PT corrective rate and can lead to deteriorated shoulder imbalance slight to moderate degrees.

Comparative Analysis of Surgical Options in the Treatment of Lumbar Degenerative Kyphosis / 대한척추외과학회지

STUDY DESIGN: A retrospective study OBJECTIVES: To compare the radiological and clinical outcomes of three surgical methods SUMMARY OF LITERATURE REVIEW: There were many proposed surgical treatments for lumbar degenerative kyphosis but the best treatment is still controversial. MATERIALS AND METHODS: Thirty three patients (all female) had undergone surgery. The mean age at surgery was 61.2. The average follow-up period was 34.7 months. The patients were divided into three groups. Group A included 7 cases with a correction by a posterior osteotomy, Group B included 15 with a posterior correction without an osteotomy, and Group C included 11 with combined anterior-posterior surgery. The radiographic measurements of lumbar lordosis, upper lumbar lordosis, lower lumbar lordosis, and pelvic tilt were performed before surgery, after surgery, and at the final follow-up visit. The loss of correction, complication rates and the clinical results were also compared. RESULTS: Postoperative correction of the lumbar and lower lumbar lordosis were significantly higher in group A and C than group B. The correction of upper lumbar lordosis was significantly higher in group A than group C. On the final follow-up, there was no significant difference in the loss of correction and clinical results between the three groups. The number of cases with complications in groups A, B and C was 4 (57%), 2 (13.3%) and 2 (18.2%), respectively. Two patients in group A required additional surgery. CONCLUSIONS: Groups A and C were more effective than posterior-only correction. There was no significant difference in the clinical results between the three groups but complication rate was higher in Group A than the other groups. Combined anterior and posterior surgery can be a safe and effective method for correction.

Posterior Correction with Segmental Pedicle Screw Fixation Alone in Severe Adolescent Idiopathic Scoliosis Over 70 degrees / 대한정형외과학회잡지

PURPOSE: To evaluate the results of a posterior procedure with segmental pedicle screw fixation in severe adolescent idiopathic scoliosis > or =70 degrees. MATERIALS AND METHODS: Twenty-three adolescent idiopathic patients with a curve magnitude > or =70 degrees subject to segmental pedicle screw fixation were analyzed retrospectively with a minimum follow-up of 2 years (2-7.8 years). There were 19 females and 4 males with a mean age of 14.9 years. All patients, except for 4 patients with King type I, were subjected to thoracic curve fusion. Twenty patients showed a thoracic curve > or =70 degrees (70-96), and 4 patients had a lumbar curve > or =70 degrees (70-77), preoperatively. The preoperative and postoperative standing roentgenograms were used to check the radiological parameters. RESULTS: The mean preoperative thoracic curve was corrected from 79.5+/-9.1 degrees to 25.3+/-5.8 degrees at the most recent follow-up, showing a correction of 67.9+/-7.8% and loss of correction of 2.5+/-1.9%. The mean preoperative lumbar curve was corrected from 72.3+/-3.3 degrees to 30.0+/-10.1 degrees at the most recent follow-up (58.4+/-14.8% curve correction, 2.4+/-2.5% loss of curve correction). The mean preoperative lowest instrumented vertebral tilting was corrected from 30.0+/-7.4 degrees to 10.5+/-5.6 degrees, showing a correction of 64.8+/-20.9%. The preoperative thoracic kyphosis improved from 28.3+/-11.2 degrees (0-50 degrees) to 35.0+/-9.1 degrees (22-53 degrees) postoperatively. There was neither pseudoarthrosis nor complications related to the pedicle screws at the most recent follow-up. CONCLUSION: Segmental pedicle screw fixation without an anterior release procedure in severe adolescent idiopathic scoliosis produced a satisfactory deformity correction with no significant loss of the curve correction. This procedure obviates the need for the anterior release and reduces the complications associated with anterior surgery.

Posterior Correction of Idiopathic Scoliosis With using Transpedicular Screw Fixation / 대한척추외과학회지

STUDY DESIGN: This is a retrospective study. OBJECTIVES: We wanted to determine the effectiveness of performing transpedicular screw fixation in idiopathic scoliosis surgery by evaluating the radiological results. LITERATURE REVIEW SUMMARY: Deformity correction using pedicle screw fixation in scoliosis surgery is one of the most effective methods of treatment. However, the extent of correction and the complication rate are quite variable. MATERIALS AND METHODS: We evaluated the radiological results of performing posterior correction with using transpedicular screws in sixty patients who were suffering with idiopathic scoliosis. The follow-up duration was 39 months (range: 12 to 91 months). The changes of the coronal and sagittal geometry in the major and compensatory curves were measured according to the Cobb method with using the anteroposterior and lateral radiographs in the standing and lateral bending positions before the surgery and at the final follow-up. RESULTS: In the coronal plane, the average correction rate of the major curve was 77% and that of the compensatory curve was 72% on the immediate postoperative radiographs. In the sagittal plane, the Cobb angle in those patients who had a hypokyphosis under 15 degrees was improved from 9.0 degrees to 21.2 degrees. The angle between the lowest instrumented vertebra and T10, and also the lumbar lordosis did not change significantly. The correction rate of the rotational deformity of the apical vertebra was 55%, and that of the translation degree was 68%. The correction rate of the translation of the lowest instrumented vertebra was 54% and that of the tilting angle was 77%. No patients had a significant loss of correction in the coronal or sagittal plane at the latest follow-up. CONCLUSIONS: Posterior correction using transpedicular screws was an effective method for treating idiopathic scoliosis, and it resulted in a high correction rate at the major curve and the compensatory curve even with short segment fixation, and it reduced the loss of the correction angle.