Trigeminal pain treatment with subcutaneous trigeminal nerve field stimulation
Trigeminal neuralgia (TN) is a distinctive facial pain syndrome that may become recurrent and chronic. It is characterized by unilateral pain following the sensory distribution of cranial nerve V (typically radiating to the maxillary or mandibular area) and is often accompanied by a brief facial spasm.
Neurosurgical pain management of drug-resistant trigeminal neuralgia (TN) was highly challenging. Micro vascular decompression was a first-line neurosurgical approach for classical TN with neurovascular conflict, but can show clinical relapse despite proper decompression.
Second line destructive techniques like radio-frequency thermo-coagulation have become reluctantly used due to irreversible side effects. Subcutaneous peripheral nerve field stimulation is a minimally invasive neuromodulatory technique which has been shown to be effective for chronic localized pain conditions. Reports on subcutaneous peripheral nerve field stimulation (sPNFS) for the treatment of trigeminal pain were still sparse and primarily focused on pain intensity as an outcome measure. As detailed data on the impact of sTNFS on attack frequency were not available, a study was conducted to evaluate the pain intensity and frequency.
In the study, patients were classified according to the International Headache Society classification. Three patients had classical TN without and another three TN with concomitant persistent facial pain. Two patients suffered from post-herpetic trigeminal neuropathy. All eight patients underwent a trial stimulation of at least 7 days subcutaneous leads in the affected trigeminal area connected to an external neuro-stimulator. Of those, six patients received permanent implantation of a neuro-stimulator. During the follow-up, VAS scores, attack frequencies, oral during intake, complications and side effects were documented.
After the completion of trial, seven out of eight patients responded to sTNFS during the test trial. The pain intensity was reduced by 83 ± 16% and the number of attacks decreased by 73 ± 26%. Five out of six patients were able to reduce or stop pain medication. One patient developed device infection. Two patients developed stimulation-related side effects which could be resolved by re-programming.
After observation, treatment by sTNFS has proven to be a beneficial option for patients with refractory trigeminal pain. Prospective randomized trials were further required to systematically evaluate the efficacy rates and safety of this low-invasive neuro-surgical technique.