Internal Neurolysis for Trigeminal Neuralgia: Technical Nuances and a Single-Institution Experience.

BACKGROUND: Trigeminal neuralgia is a facial pain syndrome most commonly caused by a neurovascular compression (NVC) of the trigeminal nerve. Microvascular decompression (MVD) is the most durable surgical treatment; however, patients without an NVC are not candidates for this procedure. Alternative treatments such as percutaneous rhizotomy and radiosurgery are effective but with higher recurrence rates. Internal neurolysis (IN) is a less frequently used procedure that aims to provide long-term relief to patients without NVC. OBJECTIVE: We present the surgical techniques for IN developed at our institution. We also discuss the technical nuances related to nerve consistency and present a new classification based on these findings. We provide pain and numbness outcomes for our cohort of patients stratified by the extent of neurolysis and nerve consistency. METHODS: Patients with medically intractable trigeminal neuralgia eligible for posterior fossa exploration are eligible for MVD and possible IN. If no NVC or a mild NVC is encountered, IN is performed. We have divided the procedure into 4 main steps: opening the outer connective sheath, fascicular dissection, inside-out dissection and the fascicular irrigation technique. Trigeminal nerve consistency has been classified into 3 main types: type 1 is soft and friable; type 2 is intermediate consistency and ideal for neurolysis; and type 3 is firm and presents a more challenging dissection. CONCLUSIONS: In the absence of microvascular compression, we advocate for a thorough neurolysis using the techniques described in our article.