Intraoperative Flash Visual Evoked Potential Recording and Relationship to Visual Outcome.

Objective: To determine the relationship between intraoperative flash visual evoked potential (FVEP) monitoring and visual function.

Methods: Intraoperative FVEPs were recorded from electrodes placed in the scalp overlying the visual cortex (Oz) after flashing red light stimulation delivered by Cadwell LED stimulating goggles in 89 patients. Restrictive filtering (typically 10-100 Hz), optimal reject window settings, mastoid reference site, total intravenous anesthetic (TIVA), and stable retinal stimulation (ensured by concomitant electroretinogram [ERG] recording) were used to enhance FVEP reproducibility.

Giant Somatosensory Evoked Potentials Coincident With Epileptiform Discharges in Acutely Comatose Patients.

Background: The amplitude of the cortically generated somatosensory evoked potential (SSEP) is used to predict outcome in comatose patients. The relationship between epileptiform discharges and SSEP amplitude has not been elucidated in those patients.

Methods: Bilateral median nerve SSEP and electroencephalograph (EEG) studies were performed in a comatose patient (patient 1) 1 day after cardiac surgery and repeated 4 days later.

Intraoperative flash VEPs are reproducible in the presence of low amplitude EEG.

Flash visual evoked potentials (FVEPs) are often irreproducible during surgery. We assessed the relationship between intraoperative FVEP reproducibility and EEG amplitude. Left then right eyes were stimulated by goggle light emitting diodes, and FVEPs were recorded from Oz–Fz′ (International 10-20 system) in 12 patients.

Intraoperative neurophysiological monitoring during circulatory arrest using deep hypothermia: A case report during brain aneurysm clipping.

Neuroprotection is the main goal during procedures that involve circulatory arrest using hypothermia. This case report describes the role intraoperative neurophysiological monitoring (IONM) plays and describes the sensitivity of specific modalities used intraoperatively to identify changes and intervene in a timely manner Understanding the contributing factors and IONM changes during hypothermia helps the neuroelectrophysiology monitorist and the surgeon to provide optimal care while minimizing morbidity. In this report we describe the role of IONM from the monitorist's perspective, describing the surgical procedure and the sequence of events.

Optimal intraoperative somatosensory evoked potential stimulus intensity can be determined by nerve action potential amplitude.

Purpose: Muscle twitch threshold has been used to determine optimal stimulus intensity for somatosensory evoked potentials but neuromuscular blockade precludes the use of muscle twitch during surgery. Accordingly, nerve action potential (NAP) amplitude was investigated as a surrogate to muscle twitch.

Methods: The ulnar and tibial nerves were stimulated at the wrist and ankle, respectively, in 27 patients undergoing spine and brain surgery.

A novel method for making dorsal horn lesions.

Objective: Dorsal root entry zone (DREZ) lesioning for intractable pain currently requires a multi-level laminectomy for direct access to all spinal cord segments intended to be lesioned. The hypothesis is that a silastic rubber catheter can be inserted into the dorsal horn (through a single laminectomy site) and advanced down several spinal cord segments, while staying exclusively in the dorsal horn.

Methods: A cervical laminectomy was performed in four sheep.

Early somatosensory evoked potential grades in comatose traumatic brain injury patients predict cognitive and functional outcome.

Objectives: To relate early somatosensory evoked potential grades from comatose traumatic brain injury patients to neuropsychological and functional outcome 1 yr later; to determine the day (within the first week after traumatic brain injury) that somatosensory evoked potential grade best correlates with outcome; to determine whether somatosensory evoked potential grade improvement in the first week after traumatic brain injury is associated with improved outcome.

Design: Prospective cohort study.

Setting: Critical care unit at a university hospital.

Generalized peripheral nerve failure during thoracic spine surgery: a case report.

Objective: Intra-operative systemic changes impairing peripheral nerve function are not commonly detected with electrophysiology. This case presentation illustrates how somatosensory evoked potential (SSEP) monitoring can detect global changes in peripheral nerve excitability during spine surgery.

Methods: A posterior thoracic spine fixation was performed on a young male with multiple traumatic injuries.

Comparison of monitoring techniques for intraoperative cerebral ischemia.

Objective: To prospectively compare somatosensory evoked potentials, electroencephalography (EEG) and transcranial Doppler ultrasound (TCD) for detection of cerebral ischemia during carotid endarterectomy (CEA).

Methods: Somatosensory evoked potentials and EEG recordings were attempted in 156 consecutive CEAs and TCD was also attempted in 91 of them. Recordings from all three modalities were obtained for at least 10 minutes before CEA, during CEA and for at least 15 minutes after CEA.

Neurogenic motor evoked potentials: role in brachial plexus surgery. Case report.

Peripheral nerve graft repair after severe brachial plexus injury is futile if there is degeneration of motor fibers in the proximal nerve stump to which the graft must be attached. Traditional intraoperative neurophysiological assessment methods like nerve action potential (NAP) and somatosensory evoked potential (SSEP) monitoring have been used to evaluate proximal nerve stump integrity, but these methods do not allow evaluation of the integrity of motor fibers back to the anterior horn cell. Consequently, the authors used transcranial electrical stimulation and recorded neurogenic motor evoked potentials (MEPs) directly from the brachial plexus in a patient undergoing surgical repair of a complete upper brachial plexus injury (Erb palsy) to assess the functional continuity of motor fibers.