Navigated pedicle screw placement in lumbar spine fusion surgery

Abstract

For the treatment of spinal instabilities arising from injuries, tumors and deformities devices with the use of transpedicular screws has become a routine procedure since the introduction by Roy-Camille [25]. However, due to the small diameter and its relation to neural structures and the screws are directed to major vessels, these technique may lead to serious complications due to misplacement of these screws [6]. Most surgeons use fluoroscopy for localizing the pedicle. But with this conventional technique the cortical perforation rate is high. Within the lumbar spine the misplacement rate is up to 30 [9, 27]. Within the thoracic spine the pedicle placement is more difficult because of the smaller diameter of the pedicle and the closeness of the spinal cord. In the literature cortical perforations of the pedicle are described up to 55 percent [29]. The incidence of neurological complications arising of such misplacements is described up to 5% [6, 9, 18]. In some cases even a placement through the cauda equina is described [5]. But also from the biomechanical point of view it is useful to hit the pedicle as precise as possible. The better the screw fills the pedicle, the higher is the fixation strength [2]. This effect is higher with a screw as long as possible. © 2007 Springer Medizin Verlag Heidelberg.