18. Intraoperative monitoring in calcified giant thoracic disc herniations in anterior thoracic approach surgery

Giant herniated thoracic disc (GHTD) is a surgical challenge with high rate of complication. This was a retrospective study of all patients with calcified GHTD operated between July 2012 and February 2017 with intraoperative neurophysiological monitoring (IOM). The study included 10 patients (9 females and 1 male). IOM study comprised: transcranial electric motor evoked potentials (MEP) and somatosensory evoked potentials (SEP) from all limbs in supine position and after lateral position. IOM MEP at the end of surgery were reduced in 4 recovered in 1, stable in 5 patients and disappeared at left lower limb in 1 patient. IOM SEP were stable in 6 patients, reduced in amplitude in 2, disappeared in 1 and in 1 case SEP at lower limbs were absent from preoperative study. The neurological outcome was stable in 9 and transitory worsened in 1 patient, who lost MEP in lower left limb. The surgical strategy was modified according to IOM findings in 4 cases leading to a partial disc excision, one where IOM MEP disappeared and 3 where MEP decreased without recovering. IOM is usefull in this combined surgery (thoracic surgery and neurosurgery) and can help to remove safely GHDT without new permanent neurological deficits.