Nerve Root Block in Spasticity

March 12, 2025 updated by: Walton Centre NHS Foundation Trust

Determination of Feasibility of Reversible Conduction Block Generated Using Peripheral Nerve Stimulator in Treatment of Focal Spasticity and the Stimulation Parameters for the Same.

In this work the investigators propose to briefly apply kilohertz frequency alternating current via PNS device placed next to the isolated nerve in 4 patients undergoing peripheral neurectomy, just before cutting the nerve. The intervention shall be performed utilizing EMG monitoring and mapping. After the muscular branches of the tibial nerve are exposed, proximal stimulation (1Hz) shall be applied to a selected branch with a bipolar electrode to produce muscle contractions. A high frequency (10kHz) blocking current shall be applied by placing a PNS electrode distally to the bipolar electrode and the EMG shall be recorded. The PNS electrode shall be removed from surgical field and further proximal stimulation done to confirm reversal of block (return to baseline) on the EMG. Then the nerve will be severed as a part of standard tibial neurectomy, and further proximal and distal stimulation shall be performed. The results will be compared to see if high frequency conduction block can physiologically mimic peripheral neurectomy; and obtain parameters of stimulation required for that.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Dysregulated neural activity is responsible for many ailments- focal spasticity after stroke or spinal cord injury, reflex incontinence, overactive bladder, etc. Current treatment options for such pathologies are suboptimal and include ablative procedures like neurectomy. Neurectomy inadvertently leads to loss of function. Modulated electrical conduction block can help control this activity without causing additional loss of function and thus has immense potential in treatment of these conditions.

Animal experiments have suggested that such a block is feasible. While safety ranges for delivery of current to human peripheral nerves are known and stimulation parameters for activation of nerves well established, further data is needed to assess the parameters for clinically useful conduction block. Currently such data studies are being conducted to block pain from neuroma after amputation and to block vagal nerve for obesity.

Peripheral Neurectomy is a procedure used for treating focal spasticity when less invasive options have been unsuccessful. The procedure is performed under full Neurophysiology monitoring. Intra-operatively, the nerve is exposed and motor activity from this is recorded spontaneously and with direct bipolar stimulation with help of EMG electrodes placed in the territory of the nerve. A tetanic response obtained upon such stimulation indicates spasticity. The nerve is cut, and further testing done by stimulating proximal and distal to the cut. Lack of tetanic response after proximal stimulation indicates adequacy of procedure.

In this work the investigators propose to briefly apply kilohertz frequency alternating current via PNS device placed next to the isolated nerve in 4 patients undergoing peripheral neurectomy, just before cutting the nerve. The intervention shall be performed utilizing EMG monitoring and mapping. After the muscular branches of the tibial nerve are exposed, proximal stimulation (1Hz) shall be applied to a selected branch with a bipolar electrode to produce muscle contractions. A high frequency (10kHz) blocking current shall be applied by placing a PNS electrode distally to the bipolar electrode and the EMG shall be recorded. The PNS electrode shall be removed from surgical field and further proximal stimulation done to confirm reversal of block (return to baseline) on the EMG. Then the nerve will be severed as a part of standard tibial neurectomy, and further proximal and distal stimulation shall be performed. The results will be compared to see if high frequency conduction block can physiologically mimic peripheral neurectomy; and obtain parameters of stimulation required for that.

This will be a proof of concept work assessing feasibility of conduction block for focal spasticity. If successful, further pilot study shall be done to assess efficacy.

Apart from brief application of high frequency stimulation, the rest of the procedure will be standard.

The stimulation will be within parameters approved by FDA and CE marking. As the nerve will then be cut anyway, there is no additional risk of harm to the nerve or the patient.

This study will adhere to the principles outlined in the UK Policy Framework for Health and Social Care Research (v3.2 10th October 2017). It will be conducted in compliance with the protocol, the EU General Data Protection Regulation 2016 and Data Protection Act 2018, and other regulatory requirements as appropriate.

Study Type

Interventional

Enrollment (Actual)

4

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • Liverpool, United Kingdom, L9 7LJ
        • The Walton Centre NHS Foundation Trust

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male or Female, aged 18 years or above selected for peripheral neurectomy for focal spasticity
  • Functioning LMN pathway determined by EMG

Exclusion Criteria:

  • Age <18yr
  • Myopathy and other LMN disorders
  • Impaired LMN pathway determined by EMG

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Nerve block
The group of participants undergoing tibial neurectomy for focal spasticity to whom the high frequency nerve conduction block shall be applied.
Procedure: High-frequency nerve conduction block
A high-frequency nerve conduction block applied to a muscular branch of the tibial nerve and assessed by intraoperative EMG, performed before the nerve is cut as a part of a standard tibial neurectomy for focal spasticity.
Other Names:
  • HFNB

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
EMG - Nerve conduction block
Time Frame: Intraoperative.
Following the application of the high-frequency current to the distal part of the nerve, the stimulated EMG shall show the decrease in amplitude [uV], compared to baseline EMG.
Intraoperative.
EMG - The reversibility of nerve conduction block
Time Frame: Intraoperative.
After stopping the high-frequency stimulation, the stimulated EMG amplitudes shall return to baseline [uV].
Intraoperative.
EMG - Comparative analysis of the effects of nerve block vs. neurectomy.
Time Frame: Intraoperative
After the nerve block is reversed, a standard tibial neurectomy shall be performed. Stimulated EMG amplitudes [uV] shall be compared to those recorded at the time of nerve block [uV].
Intraoperative

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Walton Centre NHS Foundation Trust

Collaborators

Nevro Corp

Investigators

  • Study Chair: Andrew Marshall, PhD, Walton Centre NHS Foundation Trust

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 15, 2024

Primary Completion (Actual)

December 9, 2024

Study Completion (Actual)

December 9, 2024

Study Registration Dates

First Submitted

March 7, 2025

First Submitted That Met QC Criteria

March 7, 2025

First Posted (Actual)

March 25, 2025

Study Record Updates

Last Update Posted (Actual)

March 25, 2025

Last Update Submitted That Met QC Criteria

March 12, 2025

Last Verified

March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RG420-21

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The data generated during the study comprises of EMG recordings stored on the password protected computers within the Trust. The anonymised EMG data for each participant shall be disseminated as a part of a publication.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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