Recording ocular vestibular evoked myogenic potentials intraopertively
Research type
Research Study
Full title
Intraoperative neurophysiological monitoring of the ocular vestibular evoked myogenic potential (oVEMP): A novel implementation to detect vestibular and oculomotor pathway dysfunction during brainstem surgery.
IRAS ID
270435
Contact name
Peter Walsh
Contact email
Sponsor organisation
North Bristol NHS Trust
Duration of Study in the UK
2 years, 0 months, 3 days
Research summary
Patients undergoing surgical removal of tumours in and around the brainstem are at risk of post-operative neurological deficits. Intraoperative neurophysiological monitoring can be utilised at the time of surgery to monitor the integrity of various neural pathways using auditory evoked potentials (BAEPs), somatosensory (SEP) and motor (MEP) evoked potentials and can also map out the course of these pathways.
This can help reduce the rates of deficits that occur in these pathways.
However, approximately 5-30% of patients who have brainstem surgery performed have some form of ocular motor deficit post-operative that can cause double vision, disabling nystagmus, or nerve palsy that can cause functional blindness.
However, there is no technique that can currently monitor the oculomotor function intraoperatively to help avoid these deficits.
By implementing ocular vestibular evoked myogenic potentials (oVEMP) into the armament of neurophysiological monitoring it would potentially enable the early detection of neural damage, prior to the damage becoming permanent. oVEMPs are elicited after excitation of vestibular portion of the VIIIth cranial nerve, similar to how BAEPs are elicited and they are recorded from electrodes placed around the eye, similar to the electrodes that are used to record the facial nerve responses. After excitation of the vestibular nerve, the nerve action potential passes along the medial longitudinal fascicule (MLF) in the brainstem, to cross the mid-line and excite the inferior oblique muscle that is controlled by the oculomotor cranial nerve.
Monitoring of this reflex pathway, at the same time as the other modalities are being recorded, using the same equipment already placed on the patient, could potentially avert the risk of these patients awakening with permanent vestibular ocular pathway deficits.REC name
East of England - Cambridgeshire and Hertfordshire Research Ethics Committee
REC reference
20/EE/0110
Date of REC Opinion
14 Jun 2020
REC opinion
Further Information Favourable Opinion