Positioning of pedicle screws in adolescent idiopathic scoliosis using electromyography

Abstract

<sec><title>OBJECTIVE:</title><p> To analyze the occurrence of poor positioning of pedicle screws inserted with the aid of intraoperative electromyographic stimulation in the treatment of Adolescent Idiopathic Scoliosis (AIS).</p></sec><sec><title>METHODS:</title><p> This is a prospective observational study including all patients undergoing surgical treatment for AIS, between March and December 2013 at a single institution. All procedures were monitored by electromyography of the inserted pedicle screws. The position of the screws was evaluated by assessment of postoperative CT and classified according to the specific AIS classification system.</p></sec><sec><title>RESULTS:</title><p> Sixteen patients were included in the study, totalizing 281 instrumented pedicles (17.5 per patient). No patient had any neurological deficit or complaint after surgery. In the axial plane, 195 screws were found in ideal position (69.4%) while in the sagittal plane, 226 screws were found in ideal position (80.4%). Considering both the axial and the sagittal planes, it was observed that 59.1% (166/281) of the screws did not violate any cortical wall.</p></sec><sec><title>CONCLUSION:</title><p> The use of pedicle screws proved to be a safe technique without causing neurological damage in AIS surgeries, even with the occurrence of poor positioning of some implants.</p></sec>

Intraoperative Neurophysiological Monitoring for Spinal Fusion

“…On the LILACS database, with the use of the narrow term intraoperative neurophysiological monitoring, we found 13 articles, but only 9 were related to spinal surgery. [36][37][38][39][40][41][42][43][44]…”

“…In scoliosis correction surgeries, as there is a high number of levels, there is a real risk of occurrence of poor positioning of the pedicle screws inserted, even with the aid of intraoperative electromyographic stimulation. 36 Kobayashi et al 23 studied the characteristics of cases with intraoperative transcranial motor-evoked potential waveform deterioration (defined as a decrease in intraoperative amplitude 70% of the control waveform) during posterior corrective fusion for adolescent idiopathic scoliosis. Waveform deterioration commonly occurred during rotation maneuvers and more frequently in patients with a larger preoperative Cobb angle.…”

Incidence of pedicle breach following open and minimally invasive spinal instrumentation: A postoperative CT analysis of 513 pedicle screws applied under fluoroscopic guidance

“…A cadaveric study done by Agarwal et al found the sensitivity and specificity of postoperative CT scans to pick up pedicle screw breach was 91.52% and 95.02% respectively [ 35 ]. However, not all patients with pedicle breaches present with neurological deficits [ 36 – 39 ]. Lotfinia et al reported that nerve root injury with radicular pain and/or neurological deficits was observed only in 15.1% patients with mal-positioned screws [ 12 ].…”