【Objective】 To compare the effect of thoracoscopic anterior instrumentation and conventional posterior instrumented fusion with thoracoplasty on rib and lumbar hump correction. 【Methods】 Thirty-six patients underwent thoracoscopic instrumented fusion (thoracoscopic group); and 29 patients underwent posterior segmental instrumentation with thoracoplasty (posterior group). The angle of trunk rotation (ATR) was measured at thoracic (rib hump) and lumbar (lumbar hump) region using a scoliometer in standing forward bending position pre-operatively

and at 3

6

12

and 24 months after surgery. The effect of anterior instrumentation on apical vertebral de-rotation was calculated by Nash & Moe method. 【Results】 The mean pre-operative thoracic-ATR were 13.4 and 12.8; and lumbar ATR were 5 and 4.9 for the posterior-group and thoracoscopic-group respectively. Mean percentage improvement of thoracic-ATR were 60%

56%

43%

53% in posterior-group; and 64%

58%

61%

59% in thoracoscopic-group respectively at 3

6

12

and 24 months post surgery. Differences between groups were not statistically significant. Mean grade of thoracic apex rotation in thoracoscopic-group before surgery was 2.0±0.5

and at final follow-up was 0.4±0.6. One patient improved by three grades; 21 patients (58%) improved by two grades; and 13 patients (36%) improved by one grade and one remained same at final follow-up. Mean percentage improvement of lumbar ATR were 40.8%

51.9%

43.9%

53% in posterior-group; and 66%

42%

43%

50% in thoracoscopic-group respectively at 3

6

12 and 24 months with no statistically significant difference between the groups. 【Conclusion】 Thoracoscopic instrumentation resulted in rib and lumbar hump correction similar to that of conventional posterior instrumentation. Rib hump correction in thoracoscopic anterior instrumentation is due to its vertebral de-rotation effect

similar to that observed in anterior instrumentation for thoracolumbar scoliosis.