Maintenance of trunk deformity correction following posterior instrumentation and arthrodesis for idiopathic scoliosis.

Abstract

This is a retrospective observational case series. To determine whether or not trunk deformity correction is achieved and maintained using the surgical techniques described. Transverse plane trunk deformity correction and correction maintenance have been questioned. The study group of 44 patients (40 female, 4 male) had a mean age of 16.1 years (range 10-38 years). Thirty-three had thoracic and 11 had a double curve pattern with a mean largest preoperative curve of 65 degrees. All had preoperative and follow-up at a median of 25 months (range 20-69 months); surface topography exposures quantified for both the coronal plane, as determined by the Posterior Trunk Symmetry Index, and transverse plane, as determined by the Suzuki Hump Sum, asymmetry. Thirty-four also had early postoperative studies. Change following surgery was determined by the signed rank test, with P < 0.01 being significant. Preoperative to latest follow-up largest Cobb angles had improved from a mean of 65 degrees to 23 degrees (65%, P < 0.0001), Posterior Trunk Symmetry Index from 55 to 20 (64%) (P < 0.0001), and Suzuki Hump Sum from 20 to 12 (40%) (P < 0.0001). Posterior Trunk Symmetry Index improved during the follow-up from 26 to 20 (23%) (P = 0.007). Neither Cobb nor Suzuki Hump Sum further improved or deteriorated during follow-up. These findings validate the concepts of torsional posterior spinal instrumentation and wide-thick arthrodesis to provide significant and lasting coronal and transverse plane trunk deformity correction.