Intraoperative Monitoring Services
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). Most useful during procedures involving cranial nerves and/or spinal nerve roots.
Somatosensory Evoked Potentials (SSEP)
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. Useful during surgeries involving the spinal cord, such as cervical, thoracic, and upper lumbar fusions, but can also be utilized for detecting ischemia in the brain. Losses in tcMEP responses are highly predictive of postoperative neurological motor deficits.
Pedicle Screw Stimulation
A rapid method for assessing pedicle screw breach. A hand-held probe delivers an electrical signal to the pedicle screw, and if the intensity of the electrical signal is low while an EMG response is observed, this may indicate a breach of the pedicle wall.
Electroencephalograhy (EEG)
This technique allows for surgical and ICU monitoring of cortical activity, which can be useful for determining the depth of anesthesia and seizures. Responses may be recorded prior to, during, and after drug administration or during vascular clipping.
Direct Nerve Root Stimulation/
D-wave assessment
Direct Nerve Root: 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.
D-Wave: Direct waves (D-waves) provide immediate/realtime feedback on the integrity of the lateral corticospinal tract. This technique is useful during intramedullary tumor resection. Assists surgeon in a more complete, guided resection.
Brainstem auditory evoked potentials (BAEP)
Recordings of the electrical potential changes generated by multiple structures in the auditory pathways in response to sounds presented to the ear. This test can be used to identify hemodynamic or structural insults to the brainstem as well as the VIII cranial nerve, the cochlear nucleus, and sub-cortical auditory tracts. Early detection of vasospasm or other vascular compromises such as the AICA (Anterior Inferior Cerebellar Artery) and labyrinthine artery can also 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 intraoperatively, with the right anesthetic regimine.
Cortical Mapping of Sensory and Motor/Speech Areas
The cortex is stimulated by the surgeon with a bipolar or monopolar electrode to locate the sensory and/or speech areas. This technique is useful during brain tumor resections as it allows the surgeon to identify a safe corridor to approach the tumor, as well as identifying useful landmarks.
Cortical / Subcortical Mapping of Motor Areas
Similar to above, the cortex is stimulated by the surgeon to identify the motor cortex via sub-clinical EMGs generated after cortical and/or sub-cortical stimulation.
Central Sulcus Identification
The somatosensory cortex can be mapped by recording the electrical activity from the brain in response to stimulation at the wrist or ankle and identifying the location at which a polarity reversal of the SEP occurs.
D-Wave Monitoring and Spinal Cord Mapping
Direct waves (D-waves) provide immediate feedback on the integrity of the lateral corticospinal tract. Useful during resection of intramedullary tumor removal, this technique assists in a more complete surgical resection. D-waves help guide the tumor resection, providing immediate intraoperative warning signs and alarm criteria that will assist in making surgical decisions. D-waves have been shown to be excellent prognostic indicators for long-term recovery of motor function.