Trigeminal Evoked Responses to Improve Rhizotomy

Trigeminal neuralgia (TGN) is a debilitating pain syndrome where electrical, shock- like jolts of pain affect the face. Trigeminal somatosensory evoked potentials (TSEPs) provide a promising modality for measuring the trigeminal sensory and nociceptive pathway by using peripheral stimulation of the trigeminal nerve (on the skin) and measuring low latency evoked potentials on the scalp (contralateral sensory cortex). While TSEPs have been measured in the past, it is not clear if implementing TSEPs into a routine neurosurgical rhizotomy procedure will be feasible. This is a prospective cohort study examining the feasibility of routinely performing TSEPs during rhizotomies for TGN.

Study Overview

• Status: Recruiting
• Conditions: Trigeminal Neuralgia; Rhizotomy
• Intervention / Treatment: Other: TSEP + rhizotomy surgery; Other: TSEPs recording only

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Early Phase 1

Contacts and Locations

• Study Contact: Name: Matthew Maple; Phone Number: 612-626-3582; Email: maple036@umn.edu

Study Locations

• United States
  • Minnesota
    • Minneapolis, Minnesota, United States, 55455
      • Recruiting
      • University of Minnesota
      • Contact: Matthew Maple; Phone Number: 612-626-3582; Email: maple036@umn.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults of 18 years or older
• Scheduled to undergo percutaneous rhizotomy for facial pain

Exclusion Criteria:

• For TGN: Facial pain of unclear origin (i.e. not clearly TGN pain) or Rhizotomy procedure canceled
• For Healthy control: Diagnosis or history of facial pain such as TMD or TGN, History of migraine, History of any functional pain disorder: fibromyalgia, IBS, CRPS or Recent chronic pain (within last month)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: TGN patients; Patients with TGN who will undergo rhizotomy surgery as the standard of care	Other: TSEP + rhizotomy surgery; TGN patients recruited for this study will already be undergoing percutaneous rhizotomy surgery. TSEPs will be measured at baseline prior to surgery. During the rhizotomy procedure, an electrode or balloon is placed through a metal sheath to then damage the nerve. A stylet is introduced to clear tissue from the sheath in preparation for the electrode or balloon. Prior to the final insertion of the RF electrode where the gasserian ganglion will be damaged, we will place a standard stereotactic EEG electrode (SEEG). Following damaging the nerve (clinical procedure), we will record again to measure differences in the TSEPs following cell body damage. The Neuralynx system will be used to record the potentials at 40 KHz.
Active Comparator: Healthy volunteers; Healthy volunteers for whom TSEPS will be recorded in a lab setting	Other: TSEPs recording only; TSEPS will also be recorded from healthy controls in a lab setting; all procedures for the healthy controls will be non-invasive.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Feasibility	total study procedure completion rate	3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
TSEPS peak to peak amplitude within TGN	difference in measured peak to peak amplitude between normal and TGN side	1 day
TSEPS latency within TGN	difference in measured TSEPS latency between normal and TGN side	1 day
TSEPS peak to peak amplitude between control and TGN patients	difference in measured peak to peak amplitude between healthy participants and TGN patients	1 day
TSEPS latency between control and TGN patients	difference in latency between healthy participants and TGN patients	1 day

Collaborators and Investigators

• Sponsor: University of Minnesota
• Investigators: Principal Investigator: David P Darrow, MD, University of Minnesota

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2023
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): November 1, 2026

Study Registration Dates

• First Submitted: February 7, 2023
• First Submitted That Met QC Criteria: February 17, 2023
• First Posted (Actual): February 21, 2023

Study Record Updates

• Last Update Posted (Actual): November 26, 2025
• Last Update Submitted That Met QC Criteria: November 24, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mouth Diseases; Stomatognathic Diseases; Nervous System Diseases; Cranial Nerve Diseases; Trigeminal Nerve Diseases; Facial Neuralgia; Facial Nerve Diseases; Trigeminal Neuralgia
• Other Study ID Numbers: Rhizotomy

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No