A 34-year-old male was brought to the hospital with a chest gunshot wound. Pulseless upon arrival, blood pressure was absent for 10 minutes. A thoracotomy resulted in return of spontaneous circulation. On hospital day 5, with brainstem reflexes present, he was unresponsive to call or pain, exhibited generalized hyperreflexia and bilateral Babinskys. Median nerve somatosensory evoked potentials (mSSEPs) and brainstem auditory evoked potentials were obtained. International Federation of Clinical Neurophysiology recommendations for mSSEPs and brainstem auditory evoked potentials were followed. Despite absence of the N20 responses from cortical mSSEPs no withdrawal from care was agreed upon. After awaking on day 7, mSSEPs were repeated and present. The patient survived and was discharged with minor deficits. Bilateral absence of N20 responses from mSSEPs performed beyond 48 hours after resuscitation from cardiac arrest is highly associated with bad neurological outcomes. However, variation due to hypothermia, noisy signals, medications, and brain hypo-perfusion must be taken into account.
Adult ; Blood Pressure ; Brain ; Brain Stem ; Critical Care Outcomes ; Evoked Potentials, Auditory, Brain Stem ; Evoked Potentials, Somatosensory ; Heart Arrest ; Humans ; Hypothermia ; Male ; Median Nerve ; Nervous System Diseases ; Neurophysiology ; Prognosis ; Reflex ; Reflex, Abnormal ; Resuscitation ; Thoracotomy ; Thorax ; Wounds, Gunshot

BACKGROUND AND PURPOSE: Intraoperative neurophysiological monitoring (IONM) using upper and lower somatosensory evoked potentials (SSEPs) is an established technique used to predict and prevent neurologic injury during intracranial tumor resections. Endoscopic port surgery (EPS) is a minimally-invasive approach to deep intraparenchymal and intraventricular brain tumors. The authors intended to evaluate the predictive value of SSEP monitoring during resection of intracranial brain tumors using a parallel endoscopic technique. METHODS: A retrospective review was conducted of patients operated on from 2007-2010 utilizing IONM in whom endoscopic ports were used to remove either intraparenchymal or intraventricular tumors. Cases were eligible for review if an endoscopic port was used to resect an intracranial tumor and the electronic chart included all intraoperative monitoring data as well as pre- and post-operative neurologic exams. RESULTS: 139 EPS cases met criteria for inclusion. Eighty five patients (61%) had intraparenchymal and fifty four (39%) had intraventricular tumors or colloid cysts. SSEP changes were seen in eleven cases (7.9%), being irreversible in three (2.2%) and reversible in eight cases (5.8%). Seven patients (5.0%) with intraparenchymal tumors had SSEP changes which met our criterea for significant changes while there were four (2.9%) with intraventricular (p-value=0.25). Five patients suffered post operative deficits, two reversible and two irreversible SSEP changes. Only one case exhibited post operative hemiparesis with no SSEP changes. The positive predictive value of SSEP was 45.4% and the negative predictive value was 99.2%. CONCLUSIONS: Based on the high negative and low positive predictive values, the utility of SSEP monitoring for cylindrical port resections may be limited. However, the use of SSEP monitoring can be helpful in reducing the impact of endoscopic port manipulation when the tumor is closer to the somatosensory pathway.
Brain Neoplasms ; Colloid Cysts ; Evoked Potentials ; Evoked Potentials, Somatosensory* ; Humans ; Monitoring, Intraoperative ; Paresis ; Retrospective Studies