PREOPERATIVE CT-BASED PLANNING FOR PEDICLE SCREW PLACEMENT IN CONGENITAL SCOLIOSIS SURGERY

During the last few years, pedicle screw placement for instrumented fusion of idiopathic scoliosis became a routine procedure among spinal surgeons; after the learning curve, most of the surgeons are confident to place the screws using a free-hand technique, the c-arm being used only to confirm the accuracy of screw placement. Congenital scoliosis surgery has several particularities; one of these is the difficulty of assessment of the pedicle screw trajectory for a malformed vertebra. The navigation equipment, together with the c-arm/o-arm control, make the surgeon's task less difficult. Taking into account that in their institutions, the authors do not have spine-dedicated navigation equipment, they have tried to develop a screw placement technique based on the pre-operative evaluation of the full spine ct-scan. New generation ct-scan devices allow a high-resolution scan of the entire spine in a very short time, with a radiation dose 50-70% lower than standard ct. They discuss their technique and especially the problems encountered and also the limitations of MRI as a helpful tool for this very particular surgery.