Intraoperative Continuous Flash Visual Evoked Potentials Monitoring During Endoscopic Skull Base Surgery

Not Applicable

• Conditions: Chiasmal; Lesion; Prechiasmal; Lesion
• Interventions: Other: intraoperative FVEPs monitoring

• Registration Number: NCT04068220
• Lead Sponsor: Fahad AlKherayf

Brief Summary

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.

Detailed Description

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 Timeline

• Study First Submitted: 2019-08-22
• Study First Submitted QC: 2019-08-22
• Study First Posted: 2019-08-28
• Study Start: 2020-03-02
• Status Verified: 2020-09
• Last Update Submitted: 2020-09-16
• Last Update Posted: 2020-09-18
• Primary Completion: 2021-12-31
• Study Completion: 2021-12-31

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

• Adult population (18 years and older), admitted to The Ottawa Hospital (TOH)-Civic Campus for a chiasmal or pre-chiasmal lesion, undergoing first time minimally invasive endoscopic skull base surgery

• Patient able to personally sign and date the informed consent document

• Patients will be selected based on the surgeon's determination that:

  1. The visual system will be at risk of iatrogenic injury
  2. The intraoperative FVEPs monitoring could rapidly detect this injury AND
  3. Corrective measures could be taken during surgery to reverse it.

Exclusion Criteria

• patients having a pre-existent retinal disease, cardiac pacemaker
• contraindication for total intravenous anaesthesia (TIVA)
• unable to complete required pre and post-operative visual assessment or unable to complete their post-operative follow-up visits at TOH-Civic Campus
• anticipated goggle movement related to reflection of the frontal skin flap
• preoperative visual deficits (e.g., profound deficits in visual acuity or dense visual field loss)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Intraoperative FVEPs monitoring	intraoperative FVEPs monitoring	adult patients admitted to TOH - Civic Campus, for chiasmal or pre-chiasmal lesions undergoing a first time minimally invasive endoscopic skull base surgery.

Primary Outcome Measures

Name	Time	Method
Examine the feasibility of detecting iatrogenic visual pathway injury by using intraoperative monitoring of continuous FVEPs in minimally invasive endoscopic skull base surgery.	1 year	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.

Secondary Outcome Measures

Name	Time	Method
Report the adverse events of intraoperative monitoring continuous FVEPs	1 year	Determine the number and percentage of each identified adverse event of intraoperative continuous FVEPs monitoring.
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.	1 year	Evaluation of proportions (sensitivity and specificity) and performances (positive and negative predictive values)

Trial Locations

Locations (1)

The Ottawa Hospital - Civic Campus; 🇨🇦 Ottawa, Ontario, Canada