Clinical Results of Selective Thoracic Fusion by Segmental Pedicle Screws in King type II Adolescent Idiopathic Scoliosis ( AIS )

Suk, Se Il; Kim, Jin Hyok; Kim, Won Jung; Kim, Dong Soo; Lee, Sang Min; Whang, Hoon

Abstract

STUDY DESIGN: This study analyzes the results of selective thoracic fusion by segmental pedicle screw fixation in King type II adolescent idiopathic scoliosis(AIS).
OBJECTIVES
To verify the efficacy of selective thoracic fusion by segmental pedicle screw fixation in King type II adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Decompensations following selective thoracic fusion in King type II adolescent idipathic scoliosis have been attributed to relative inability of the lumbar curves to accommodate correction of the thoracic curves. However, with segmental pedicle screw fixation, selective thoracic fusions yielded satisfactory results in most of the patients regardless of the lumbar curve characteristics.
MATERIALS AND METHODS
Eighty patients subjected to selective thoracic fusion by segmental pedicle screw fixation were analyzed after a minimum follow-up of 2 years for deformity correction and spinal balance. Deformity correction was performed by derotation of rod contoured to the normal sagittal curve without additional compression or distraction.
RESULTS
Mean preoperative thoracic curve of 53.3 was corrected to 20.3 showing a correction of 63.2%. The mean preoperative lumbar curve was 34.4 with a flexibility of 97.2% and mean lumboapical distance(LAD)of 18.0mm, L4 tilt of 8.0, and lumbar apical rotation (LAR) of 10.9. It was corrected to 16.5 showing a correction of 55.5%. All the patients were balanced clinically and radiologically.
CONCLUSIONS
Selective thoracic fusion with segmental pedicle screw fixation and rod rotation offers a satisfactory correction of the deformity and maintenance of spinal balance in King type g AIS regardless of lumbar curve magnitude, LAD, L4 tilt or LAR.