SERVICES

PNS offers intraoperative neurophysiological monitoring services to surgeons and their patients.  Neurophysiological monitoring is utilized to minimize neurological morbidity from operative techniques.  Neurophysiological monitoring assists the surgeon by predicting neurophysiological/functional change in brain, spinal cord, and peripheral nerves prior to irreversible damage.

Intraoperative monitoring (IOM) allows early intervention for the prevention of neuronal compromise throughout surgical procedures. Continuous measurements are compared to the patient's own baseline data, thus neurophysiological changes due to body positioning or surgical manipulation can immediately be detected.

PNS has a staff of certified surgical neurophysiologists who provide high quality, state-of-the-art intraoperative monitoring. We are dedicated to providing patients with the most appropriate care possible.

Test Performed and Techniques Used During Surgery

Electromyography (EMG) recordings of the electrical activity generated when a muscle contracts. Free-running EMGs (for spontaneous activity) are used to record activation of nerve roots and Triggered EMGs (response to stimulation) are recorded. Most useful during procedures involving cranial nerves and/or spinal nerve roots.

Somatosensory Evoked Potentials (SSEP) are recordings from cortical and/or subcortical structures in response to peripheral stimulation. SSEPs are used to assess the functional status of the sensory pathways during surgeries which may affect peripheral nerves, spinal cord, and brain.

Transcranial motor evoked potentials (tcMEP) responses obtained from muscle groups in response to electrical stimulation of the motor cortex through the cranium. tcMEPs provide instantaneous feedback about the integrity of the motor tracts. Losses in tcMEP responses are highly predictive of post-operative neurological motor deficits.

Pedicle Screw Stimulation is a rapid method for assessing pedicle screw/bone purchase.  A hand-held probe delivers an electrical signal to the pedicle screw and the EMG activity observed.  If the intensity of the electrical signal is low and response is observed a breach of the pedicle wall is suggested.

Direct Nerve Root Stimulation provides immediate information on nerve root function.  The surgeon uses a hand-held probe that sends an electrical signal to the neural tissue. Stimulation of nervous tissue results in EMG activity in peripheral muscles. This test defines neural and nonneural tissue; motor and sensory nerve roots and can be used to conform neural integrity.

Brainstem auditory evoked potentials (BAEP) recordings of the electrical potential changes generated by multiple structures in the auditory pathways in reponse to sounds presented to the ear.  Auditory brainstem responses (ABRs) can be used to identify hemodynamic or structural insults to the brainstem as well as the VIIIth cranial nerve, the cochlear nucleus, and sub-cortical auditory tracts.  Early detection of vasospasm or other vascular compromises in particular AICA (Anterior Inferior Cerebellar Artery) and labryrinthine artery can be identified.

Visual evoked potentials (VEPs), analogous to ABRs, but are produced by visual transients which evoke activity in the visual central nervous system.  VEPs can be recorded in the O.R., however anesthetic requirements for their recording many times precludes their use.

Cortical Mapping of Sensory and Speech Areas (awake) — The cortex is stimulated with a bipolar or monopolar electrode to locate the sensory and/or speech areas.

Cortical / Subcortical Mapping of Motor Areas — The cortex is stimulated by the surgeon with a hand-held bipolar or monopolar electrode and the motor cortex is identified and localized by recording sub-clinical EMGs generated after cortical and/or sub-cortical stimulation.

Central Sulcus Identification — Somatosensory cortex is mapped by recording the electrical activity from the brain in response to stimulation at the wrist or ankle. The location of the central sulcus is identified by finding the location at which a polarity reversal of the SEP occurs.

Electroencephalography (EEG) — Surgical and ICU monitoring of cortical activity. Responses may be recored prior to, during and after drug administration or during vascular clipping.

Reflex studies provide information regarding the integrity of 1) peripheral afferent input, 2) segmental neurons, and 3) propriospinal tracts.