Factors as predictors for thoracic and thoracolumbar/lumbar structural curves in adolescent idiopathic scoliosis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recent studies have demonstrated that the Lenke system is relatively efficient and consistent in classifying scoliosis curves. Basically, fusion should include the main curve and the structural minor curve. The criteria for defining the structural minor curve were established to help guide these decision-making process. The present study was designed to investigate predictors of the structural curve, and see whether it was possible to prevent the formation of the structural curve by interfering with influencing factors to decrease the fusion level.</p><p><b>METHODS</b>Age, gender, Cobb angle, Perdriolle rotation, Risser sign and the number of vertebrae included in the curve, brace treatment, and curve location were recorded in 145 idiopathic scoliosis patients from July 2001 to January 2007. The patients were divided into two groups: structural and non-structural groups. Demographics and baseline characteristics were compared between the two groups as an initial screen. Logistic regression was used to analyze factors affecting the minor curve to become the structural curve.</p><p><b>RESULTS</b>Compared with the non-structural group, the structural group had a higher Cobb angle ((51.34 ± 13.61)° vs. (34.20 ± 7.21)°, P < 0.001), bending angle ((33.94 ± 9.92)° vs. (8.46 ± 5.56)°, P < 0.001) and curve rotation ((23.25 ± 12.86)° vs. (14.21 ± 8.55)°, P < 0.001), and lower flexibility ((33.48 ± 12.53)% vs. (75.50 ± 15.52)%, P < 0.001). There was no significant difference in other parameters between the two groups. The results of the Logistic regression analysis showed that the Cobb angle (OR: 9.921, P < 0.001) and curve location (OR: 4.119, P = 0.016) were significant predictors of structural curve in adolescent idiopathic scoliosis. Every 10° change of Cobb angle increased the possibility of turning the minor curve into the structural curve by 10-fold. And thoracic curve showed, on the average, the possibility of becoming the structural curve about 4-fold more often than did the thoracolumbar/lumbar curve.</p><p><b>CONCLUSIONS</b>Curve severity and curve location affect the minor curve's structural features in adolescent idiopathic scoliosis.</p>

Learning curve of computer-assisted navigation system in spine surgery / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Spine surgery using computer-assisted navigation (CAN) has been proven to result in low screw misplacement rates, low incidence of radiation exposure and excellent operative field viewing versus the conventional intraoperative image intensifier (CIII). However, as we know, few previous studies have described the learning curve of CAN in spine surgery.</p><p><b>METHODS</b>We performed two consecutive case cohort studies on pedicel screw accuracy and operative time of two spine surgeons with different experience backgrounds, A and B, in one institution during the same period. Lumbar pedicel screw cortical perforation rate and operative time of the same kind of operation using CAN were analyzed and compared using CIII for the two surgeons at initial, 6 months and 12 months of CAN usage.</p><p><b>RESULTS</b>CAN spine surgery had an overall lower cortical perforation rate and less mean operative time compared with CIII for both surgeon A and B cohorts when total cases of four years were included. It missed being statistically significant, with 3.3% versus 4.7% (P = 0.191) and 125.7 versus 132.3 minutes (P = 0.428) for surgeon A and 3.6% versus 6.4% (P = 0.058), and 183.2 versus 213.2 minutes (P = 0.070) for surgeon B. In an attempt to demonstrate the learning curve, the cases after 6 months of the CAN system in each surgeon's cohort were compared. The perforation rate decreased by 2.4% (P = 0.039) and 4.3% (P = 0.003) and the operative time was reduced by 31.8 minutes (P = 0.002) and 14.4 minutes (P = 0.026) for the CAN groups of surgeons A and B, respectively. When only the cases performed after 12 months using the CAN system were considered, the perforation rate decreased by 3.9% (P = 0.006) and 5.6% (P < 0.001) and the operative time was reduced by 20.9 minutes (P < 0.001) and 40.3 minutes (P < 0.001) for the CAN groups of surgeon A and B, respectively.</p><p><b>CONCLUSIONS</b>In the long run, CAN spine surgery decreased the lumbar screw cortical perforation rate and operative time. The learning curve showed a sharp drop after 6 months of using CAN that plateaued after 12 months; which was demonstrated by both perforation rate and operative time data. Careful analysis of the data showed CAN is especially useful for less experienced surgeon to reduce perforation rate and intraoperative time, although further comparative studies are anticipated.</p>

Analysis of posterior pedicle screw-only constructs in surgical treatment of adolescent idiopathic scoliosis with a minimum three-year follow-up / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate clinical outcomes of a group of adolescent idiopathic scoliosis (AIS) patients undergoing posterior pedicle screw-only instrumentations.</p><p><b>METHODS</b>Between April 2002 and July 2006, 121 AIS patients (93 female and 28 male, average age at operation was 15.5 years which ranged from 10 to 20 years) received posterior pedicle screw-only instrumentation and fusion. All the patients were evaluated by the various-parameters measured in X-ray films before and after surgery, including Cobb angle on coronal plane, Cobb angle on sagittal plane, clavicle angle and shoulder height difference, lowest instrumented vertebrae (LIV) angulation, proximal junction kyphotic angle, the distances of central sacral vertical line (CSVL) to the LIV, to the apical vertebra and to the C(7) plumb line respectively. Complications were followed.</p><p><b>RESULTS</b>An average of (11.0 + or - 1.5) levels was fused. An average coronal correction of proximal thoracic curve was 41.8%, of thoracic curve was 70.8%, of thoracolumbar/lumbar curves was 74.0%. No significant change was found in sagittal alignment. Shoulder balance and apex vertebral to central sacral line were restored well. There were no pseudoarthroses and loss of correction during the follow-ups. One adding-on, 4 proximal thoracic decompensation and 15 proximal junction kyphosis were found during the follow-ups.</p><p><b>CONCLUSION</b>Posterior pedicle screw-only instrumentation and fusion has excellent radiographic and clinical results with minimal complications in the surgical treatment of AIS.</p>