Radiological evaluation of positions of pedicle screws which are instrumented with neuromonitoring

This study aims to evaluate the positions of pedicle screws in patients which are instrumented with intraoperative neurophysiological neuromonitoring. Patients who admitted to our clinic, and had operation between April – 2011 and March – 2014 were included the study. One of 58 evaluated patients was excluded the study due to new neurological deficit postoperatively without neuromonitoring warn. 31 of 57 patients were male (54.4%) and 26 of 57 patients were female (45.6%). 21 patients were operated for deformity, 31 patients were operated for malignancy, 5 patients were operated for compression fracture due to osteoporosis. Total intravenous anesthesia technique was used for all patients. 1167 pedicle screws were used for patients totally. 817 pedicle screws were used in thoracic region. 335 pedicle screws were used in lomber region. 66 medial wall penetration were found totally. 41 of 66 were in thoracic region, 25 of 66 were in lomber region. Penetration rates of screws were found 5% for thoracic region, and 7% for lomber region. T12 and L1 have the highest rate for penetration (13.8 %). Reliability of neuromonitoring was found 98.3 %. There is no significant difference between penetration rate and diagnosis (p=0,332). There is significant relationship between penetration rate and number of used screw (p=0,009). There is a weak positive correlation between number of used screw and surgery time (r=0.293 , p=0.027). There is a modarate correlation between number of used screw and blood loss (r=0.499, p=0.001). There is a significant difference for penetration rate (p=0,009) between thoracal and lomber region. Consequently neuromonitoring was evaluated as a useful method in this study for improving patient safety with preventing development of new neurological deficit even it does not prevent penetration of pedicle screws exactly.