Spinal osteotomies are inherently high-risk surgeries for neurological deficit, and the incidence varies from 0.06 to 11 % depending upon the series and the nature of osteotomy (Table 19.2). It is mandatory that the possibility of a postoperative deficit is discussed with the patient in every case. Intraoperative spinal cord monitoring must also be utilised to identify any untoward cord accident at the earliest possible, as early identification and immediate action can result in reversal of the deficit.

The reason for a neurological deficit is sometimes obvious but many times not (Fig. 19.1). Spinal osteotomies are complex surgical procedures which can cause neurological deficit in many different mechanisms. Inadvertent placement of the implants is a well-known cause for neurological deficit. Although the injury due to intracanal placement of screws and wires is ever present in any spine surgery, this risk is more in patients requiring osteotomy due to the presence of three-dimensional deformity and different pedicle orientations at each segment of the deformed segments (Fig. 19.2). The process of correcting the deformity involves mobilisation and distraction of the cord, which can either cause a direct neurological deficit or compromise the vascular supply to the cord. Intraoperatively, the laminae at the margins of the decompression, especially the lower border of the upper laminae, can compress the cord during correction. Any movement or mobilisation of the dura can also compromise the blood supply and result in deficit.