Paresthesia-free Peripheral Nerve Field Stimulation for Trigeminal Neuralgia (FreeST Trial)

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

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 surgeryAverage preoperative episodic/constant pain intensity of 5 or greater out of 10 cm on the VASCapable of providing informed consent and complying with study proceduresPatients 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 perceptionPatients 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