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As part of a nationally renowned teaching program, the UC department of otolaryngology provides a number of services to area physicians. These include the following:
Intraoperative Monitoring Division
A wide range of monitoring services are available from our certified neurodiagnostic intraoperative monitoring personnel. Common modalities include:
- Somatosensory evoked potentials (SSEP)
- Electromyography (EMGs and t-EMGs)
- Auditory brainstem responses (ABR)
- Transcranial motor evoked potentials
- Spinal cord mapping
- Cortical mapping
- Facial nerve monitoring
- Pedicle screw monitoring
What is the purpose of Intraoperative monitoring?
Intraoperative monitoring (IOM) helps prevent dysfunction of the brain, cranial nerves, spinal cord and peripheral nerves. IOM can also facilitate mapping of the motor cortex and spinal cord.
IOM is suggested for cases in which surgical complications may cause a loss of neurological function, such as surgery of the spine, brain and nerve plexus. The use of neuromonitoring can assist in preventing or reversing loss of function. Suggested cases include:
- Tumor resection
- Arterial aneurysm repair
- Arteriovenous malfunction repair
- Spinal procedures
- Carotid endarterectomy
- Brachial plexus exploration
- Deep brain stimulator implantation
- Brainstem function assessment
- Tethered spine release
- Elimination of hemifacial spasms
Monitoring personnel with the Intraoperative Monitoring Division have OR privileges at numerous hospitals in the Greater Cincinnati Area, including:
- Bethesda-North Hospital
- Deaconess Hospital
- Good Samaritan Hospital
- Jewish Hospital – Kenwood
- Mercy-Anderson Hospital
- Mercy-Fairfield Hospital
- Mercy-Mt. Airy Hospital
- Mercy-Western Hills Hospital
- The Christ Hospital
- University Hospital Medical Center
- Veterans Administration Hospital
Intraoperative Neurophysiological Monitoring Limitations and Concerns:
The following characteristics of intraoperative monitoring technology should be understood by the surgeon:
- All monitoring modalities are rendered unusable during use of electrocautery devices (e.g. the Bovie and Bipolar), including “alarm” signals that annunciate EMG activity upon mechanical nerve stimulation.
- Free-running EMG monitoring is usually disabled during SSEP monitoring periods, except when EMG monitoring is limited to cephalic regions. To facilitate frequent monitoring of SSEPs, which often require one minute for acquisition and averaging, the surgeon must stop operating during recording if strategic timing of signal sampling cannot be accomplished safely.
- Changes in SSEP signals may be undetectable for several minutes or more after an ischemic event. Changes in motor evoked potential (MEP) signals, although similarly not immediate following an ischemic event, are generally more quickly observable.
- Motor evoked potential (MEP) monitoring involves transcranial stimulation of the patient’s motor cortex with voltage levels as high as 1,000 Volts. Because of this, the patient must be protected from all potentially dangerous muscle contractions that may occur during MEP monitoring. Soft bilateral mouth guards that protect the teeth and tongue are required, and care must be exercised to ensure that strong muscle contractions cannot result in the patient’s head becoming dislodged from pinning devices.MEP monitoring is contraindicated if the patient has a pacemaker, metal plates on the skull or a history of seizure activity.
Cooperation of anesthesia personnel is required because MEPs are often completely inhibited by the use of even small amounts of inhalants, including nitrous oxide.
Spinal cord MEP monitoring requires numerous muscles be monitored. The surgeon should understand that the time required to place and make connections to electrodes could delay the start of surgery.
Although muscle contractions involved in MEP testing occur quickly, it is sometimes necessary for the surgeon to briefly stop activity during patient movement.
MEP responses can be obtained in only 80 to 85 percent of IOM situations.
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