Skull base surgeries performed in areas involving the visual pathway are associated with varying levels of postoperative visual dysfunction. The goal of intraoperative FVEP monitoring is to detect and prevent intraoperative visual pathway injury.
Skull base surgeries performed in areas involving the visual pathway are associated with varying levels of postoperative visual dysfunction. For instance, surgical resection of suprasellar meningiomas has been shown to worsen visual function in 14 - 28% of patients and surgical resection of craniopharyngiomas worsen visual function in 3 - 11.5% of patients. Manipulation of the optic nerve and interference with the microvasculature during surgical dissection is thought to be responsible for the visual loss. Through intraoperative monitoring and prompt identification of flash visual evoked potentials (FVEPs) deterioration, corrective surgical measures could be undertaken to improve or stabilize postoperative visual dysfunction. Furthermore, intraoperative FVEPs monitoring may influence surgical decision-making thus contributing to predict and prevent postoperative visual dysfunction as well as allowing more total resection of a tumour when the monitoring is stable. This study's aim is to determine if intraoperative continuous FVEPs monitoring can predict and prevent or minimize possible visual pathway injury that may appear during minimally invasive endoscopic skull base surgery.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
40
During the surgery, a pair of goggles (similar to the swimming goggles) will be placed on patient's closed eyes. The goggles equipped with red LEDs will apply no pressure or minimal pressure on patient's closed eyes. Patient's left eye then right eye will be stimulated with flashing red light emitted by the goggles. Two subdermal needle electrodes will be placed under the skin behind patient's ears, and one subdermal needle electrode will be placed under the skin above the bridge of patient's nose. The two electrodes placed behind patient's ears, will record intraoperative flash visual evoked potentials (FVEPs) resulted from red light stimulation of patient's visual pathway through the eyes and the electrode above the bridge of the nose will record, at the same time, the activity of each eye's retina.
The Ottawa Hospital - Civic Campus
Ottawa, Ontario, Canada
RECRUITINGExamine the feasibility of detecting iatrogenic visual pathway injury by using intraoperative monitoring of continuous FVEPs in minimally invasive endoscopic skull base surgery.
This pilot study will evaluate the number of enrolled patients with stable and reliable FVEPs with ERGs, the number of enrolled patients with more than 50% decrease in intraoperative FVEPs N1-P1 amplitude (compared to baseline value) and the number of patients with permanent postoperative visual deficit. In addition, we will use demographic data for descriptive analysis, and obtain preliminary data for power analysis and information on subject recruitment before starting the large clinical trial.
Time frame: 1 year
Determine sensitivity and specificity as well as positive and negative predictive value of intraoperative monitoring of continuous FVEPs in minimally invasive endoscopic skull base surgery.
Evaluation of proportions (sensitivity and specificity) and performances (positive and negative predictive values)
Time frame: 1 year
Report the adverse events of intraoperative monitoring continuous FVEPs
Determine the number and percentage of each identified adverse event of intraoperative continuous FVEPs monitoring.
Time frame: 1 year
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