The Effect of Increasing Current or Pulse Duration on Patient Movement and Intraoperative Transcranial Electric Stimulation Motor Evoked Potential Amplitude

NCT05375669 | Completed

• 1 other identifier: CCCV
• Study Type: interventional
• Target: 31
• Locations: 1 country
• Sites: 1

Brief Summary

Transcranial electric stimulation (TES) motor evoked potential (MEP) monitoring is standard during surgery risking motor system injury. The stimuli are typically 5-pulse trains with a 4 ms interstimulus interval (ISI). The pulse duration (D) is often set to 50 or 500 µs. Both are effective, but setting D to the chronaxie would be physiologically optimal and limited data suggest that mean MEP chronaxie may be near 200 µs. When necessary, one can obtain larger MEPs by increasing current (I) or D to increase stimulus charge (Q = I × D). However, this also increases patient movement that can interfere with surgery and reduce MEP acquisition frequency. The main research question is whether increasing current or pulse duration when applying intraoperative neuromonitoring produces less patient movement during surgery. As such, the IOM ISIS System will be employed for neuromonitoring and an accelerometer will be used to quantify patient movement. The constant-current TES stimulators will be used in this study with a high-precision oscilloscope. Total intravenous anesthesia (TIVA), surgery and TES MEP monitoring will proceed routinely without modification and normally involves acquiring many MEPs over several hours. The only departure from standard care will be the placement of two small accelerometers and a brief MEP sequence before skin incision to determine chronaxie and compare the effect of an equivalent increase of I or D on MEP amplitude and movement.

Conditions

Surgery

Outcome Measures

Primary Outcomes (1)

• Comparison of the effect of a 2-fold increase of I or of D from threshold on patient movement

  Comparison of the effect of a 2-fold increase of I or of D from threshold on patient movement quantified by accelerometers on the patient's forehead and contralateral (non-affected) shoulder.

  During surgery, estimated on average to be about 4 hours

Secondary Outcomes (2)

• Comparing the effect of a 2-fold increase of I or of D from threshold on MEP amplitude

  During surgery, estimated on average to be about 4 hours

• Chronaxie

  During surgery, estimated on average to be about 4 hours

Study Arms (1)

ISIS IOM System

EXPERIMENTAL

Total intravenous anesthesia (TIVA), surgery and TES MEP monitoring will proceed routinely without modification and normally involves acquiring many MEPs over several hours. The only departure from standard care will be the placement of two small accelerometers and a brief MEP sequence before skin incision to determine chronaxie and compare the effect of an equivalent increase of I or D on MEP amplitude and movement.

Device: ISIS IOM System

Interventions

ISIS IOM System DEVICE

The constant-current TES stimulators will be used in this study with a high-precision oscilloscope. The calibration will assess 5-pulse trains with a 4 ms ISI and 100 mA output across a 1000 Ω resistor at 250, 500, and 1000 µs D. Measurements will include actual I and D of each pulse, and actual ISI. Total intravenous anesthesia (TIVA), surgery and TES MEP monitoring will proceed routinely without modification and normally involves acquiring many MEPs over several hours. The only departure from standard care will be the placement of two small accelerometers and a brief MEP sequence before skin incision to determine chronaxie and compare the effect of an equivalent increase of I or D on MEP amplitude and movement.

ISIS IOM System

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Informed Consent signed by the subject
• The patient has a supra- or infra-tentorial lesion requiring surgery
• The patient is undergoing neurosurgery with the use of Intraoperative Monitoring (IOM) during surgery to protect functional tissue
• The patient is older than 18 years

You may not qualify if:

• No need for Intraoperative Monitoring (IOM)
• Vulnerable subjects (pregnant women, pregnant, impaired consciousness)
• People who do not want to participate in the study
• Emergency procedures in which no consent was obtained before the operation
• Multiple surgeries on the same patient
• Preoperative non-affected arm motor deficit (MRC \<5), that is to say, no motor deficit of the arm ipsilateral to the surgery
• Inhalational anesthesia
• Persisting neuromuscular blockade

Sponsors & Collaborators

• Insel Gruppe AG, University Hospital Bern: lead

Study Sites (1)

Dep. of Neurosurgery, Bern University Hospital

Bern, 3010, Switzerland

Location

Related Publications (5)

• Szelenyi A, Kothbauer KF, Deletis V. Transcranial electric stimulation for intraoperative motor evoked potential monitoring: Stimulation parameters and electrode montages. Clin Neurophysiol. 2007 Jul;118(7):1586-95. doi: 10.1016/j.clinph.2007.04.008. Epub 2007 May 15.

  PMID: 17507288 BACKGROUND

• Abalkhail TM, MacDonald DB, AlThubaiti I, AlOtaibi FA, Stigsby B, Mokeem AA, AlHamoud IA, Hassounah MI, Baz SM, AlSemari A, AlDhalaan HM, Khan S. Intraoperative direct cortical stimulation motor evoked potentials: Stimulus parameter recommendations based on rheobase and chronaxie. Clin Neurophysiol. 2017 Nov;128(11):2300-2308. doi: 10.1016/j.clinph.2017.09.005. Epub 2017 Sep 28.

  PMID: 29035822 BACKGROUND

• Macdonald DB, Skinner S, Shils J, Yingling C; American Society of Neurophysiological Monitoring. Intraoperative motor evoked potential monitoring - a position statement by the American Society of Neurophysiological Monitoring. Clin Neurophysiol. 2013 Dec;124(12):2291-316. doi: 10.1016/j.clinph.2013.07.025. Epub 2013 Sep 18.

  PMID: 24055297 BACKGROUND

• MacDonald DB. Safety of intraoperative transcranial electrical stimulation motor evoked potential monitoring. J Clin Neurophysiol. 2002 Oct;19(5):416-29. doi: 10.1097/00004691-200210000-00005.

  PMID: 12477987 BACKGROUND

• Eng J. Sample size estimation: how many individuals should be studied? Radiology. 2003 May;227(2):309-13. doi: 10.1148/radiol.2272012051.

  PMID: 12732691 BACKGROUND

Study Officials

• Kathleen Seidel, MMD

  Inselspital Bern, Department of Neurosurgery

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Patients will be screened as part of the clinical routine and will be included if they satisfy the eligibility criteria and sign the informed consent. All the study subjects who are included are patients who undergo surgery

Study Record Dates

• First Submitted: April 21, 2022
• First Posted: May 17, 2022
• Study Start: August 10, 2022
• Primary Completion: November 1, 2024
• Study Completion: November 1, 2024
• Last Updated: April 1, 2025

Record last verified: 2025-03

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)