Clinical trial NCT05615714: Paresthesia-free Peripheral Nerve Field Stimulation for Trigeminal Neuralgia (FreeST Trial)
Official title: Paresthesia-free Peripheral Nerve Field Stimulation for Trigeminal Neuralgia: a Double-blinded, Randomized Trial (FreeST Trial)
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: PHASE1
PHASE2
Conditions: Trigeminal Neuralgia
Facial Pain
Keywords: Peripheral Nerve Field Stimulation
Lead sponsor: University Health Network, Toronto
Sponsor class: OTHER
First posted: 2022-11-14
Enrollment: 24
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: Study type: Prospective, double-blinded, double arm, cross-over, randomized controlled clinical trial.

Brief protocol:

Postoperative week 0-2 -\> Conventional parameters (parameters tested during trial period)

Postoperative week 2-6 -\> Sham stimulation (2 weeks) and paresthesia-free stimulation (2 weeks) double-blind crossover design

Postoperative week 6 - month 12 -\> Parameters that patients feel more benefit from

Detailed description: Background:

Peripheral Nerve Field Stimulation (PNFS) has been utilized for the treatment of facial pain for around 60 years, and the commercial devices needed to deliver PNFS have been available for around 30 years. The safety and efficacy of the procedure has been demonstrated by various uncontrolled observational studies. It serves as a part of daily neurosurgical practice for selected patients in UHN Toronto Western Hospital. This therapeutic modality involves subcutaneous implantation of electrodes in the vicinity of trigeminal nerve branches and application of electrical current using a permanently implanted pulse generator (IPG). Similar to other forms of neuromodulation, PNFS is non-ablative, reversible, adjustable and associated with a relatively low risk of severe complications. A meta-analysis of paresthesia-inducing (PI) PFNS studies in the literature revealed a treatment efficacy of 75% decrease in VAS scores (mean difference: -6.32 out of 10) with PNFS utilization for facial pain. (PMID: 35180702)

Study design:

Patients who underwent a successful unilateral PNFS implantation surgery (trial and permanent implantation) for a facial pain syndrome as a standard of care treatment, will be screened for inclusion after permanent implantable pulse generator (IPG) implantation. Upon consent, the investigators will set up participants' IPG to deliver stimulation with parameters tested during the trial period (paresthesia-inducing parameters) for 2 weeks. The participants will come back to hospital at postoperative week 2 and will be randomized (1:1 ratio) between the two arms of the study (Group 1= sham, Group 2= paresthesia-free (PF) stimulation). Each participant will consecutively experience all two stimulation groups by 2-week periods in a crossover design. Both participants and clinical investigators that will assess the pain will be blind during the study period (between postoperative week 2 and 6). After 6 weeks, the treatment arms will be merged and all the participants will receive any stimulation parameter that they feel more benefit from ("best" parameter). Outcomes will be assessed 6 and 12 months post-operatively.

Eligibility criteria: Inclusion Criteria:

* Diagnosis of a medically-refractory unilateral facial pain syndrome as defined by the Burchiel classification but excluding atypical facial pain (somatoform pain disorder)
* Recent successful PNFS trial and permanent implantation surgery
* Average preoperative episodic/constant pain intensity of 5 or greater out of 10 cm on the VAS
* Capable of providing informed consent and complying with study procedures
* Patients may or may not use a pain medication at the time of recruitment. Medications allowed during the study are long-acting/modulatory analgesics (anticonvulsants such as carbamezapine, oxcarbazepine, pregabalin, gabapentin, lamotrigine; baclofen, botox injections) and short-acting analgesics (non-steroid anti-inflammatory drugs, short-acting opioids, lidocaine or sumatriptan injections)

Exclusion Criteria:

* Currently in a clinical trial involving an investigational product or non-approved use of a drug or device.
* Active psychiatric disorder or other known condition that can significantly impact pain perception
* Patients with a revision surgery of a PNFS system by any reason (history of trigeminal pain surgery of other types (i.e., microvascular decompression, gamma knife, percutaneous rhizotomies) are not exclusion criteria)
* Pregnant and lactating women

Primary outcomes:
measure: Visual Analogue Scale (VAS) Score Change
timeFrame: Postoperative week 2 to week 6
Secondary outcomes:
measure: Visual Analogue Scale (VAS) Score Change
timeFrame: Postoperative week 0 to week 6
measure: Barrow Neurological Institute (BNI) pain intensity score change
timeFrame: Postoperative week 0 to week 6
measure: Brief Pain Inventory (BPI) score change
timeFrame: Postoperative week 0 to week 6
measure: Clinician and Patient Global Impression of Change Scale and Patient satisfaction scale score change
timeFrame: Postoperative week 0 to week 6
measure: Adverse effect Profile
timeFrame: Postoperative week 0 to month 12
measure: Ratio of patients who chose paresthesia-free or paresthesia-inducing stimulation at week 6, month 6 and 12
timeFrame: Postoperative week 6, month 6 and 12
measure: fMRI BOLD signal change
timeFrame: Between postoperative month 6 and 12
measure: Visual Analogue Scale (VAS) Score Change
timeFrame: Postoperative month 6 and 12
measure: Barrow Neurological Institute (BNI) pain intensity score change
timeFrame: Postoperative month 6 and 12
measure: Brief Pain Inventory (BPI) score change
timeFrame: Postoperative month 6 and 12
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: Toronto Western Hospital, University Health Network
state: Ontario
city: Sherbrooke
country: Canada
facility: Centre hospitalier universitaire de Sherbrooke
state: Quebec
Study officials:
affiliation: University of Toronto
name: Mojgan Hodaie, MD, MSc
role: PRINCIPAL_INVESTIGATOR
References: