A new technique for intraoperative analysis of trunk geometry in adolescent idiopathic scoliosis.

Can J Surg, Vol. 45, No. 3, June 2002 219 A idiopathic scoliosis (AIS) involves a deformity of the spine that is commonly assessed by physicians. The external trunk deformity is also recognized as a major concern in AIS, especially for the patient. Therefore, many authors advocate that that consideration be given to simultaneous surgical correction of spinal and trunk deformities. During posterior instrumentation of the scoliotic spine, the main objective is to restore a well-balanced spine in sagittal, coronal and transverse planes. Intraoperatively, surgeons can evaluate the spinal correction by direct visualization of the exposed vertebrae or by such techniques as radiography, stereophotogrammetry, and optoelectronic or electromagnetic tracking. However, visual evaluation of the scoliotic trunk deformity is difficult since draping sheets cover most of the trunk. In addition, an adequate correction of the spinal deformity does not guarantee successful correction of the trunk deformity. To achieve an overall correction of AIS, it would be useful for the surgeon to have immediate feedback regarding the efficacy of the surgical manoeuvres on the trunk deformity. Mac-Thiong and colleagues recently developed a technique to assess scoliotic trunk geometry in the prone operative position, but they have never used it in a surgical environment. The purpose of this study was to evaluate the feasibility of this technique during surgical correction of AIS. The trunk geometry of a patient undergoing surgical treatment of AIS was quantified at various stages of the procedure.