Pathophysiology of Trigeminal Neuralgia: The Ignition Hypothesis

Abstract

There are no satisfactory animal models of trigeminal neuralgia, and it is difficult to obtain essential data from patients. However, trigeminal neuralgia presents with such idiosyncratic signs and symptoms, and responds to so distinctive a set of therapeutic modalities, that scientific deduction can be used to generate likely hypotheses. The ignition hypothesis of trigeminal neuralgia is based on recent advances in the understanding of abnormal electrical behavior in injured sensory neurons, and new histopathologic observations of biopsy specimens from patients with trigeminal neuralgia who are undergoing microvascular decompression surgery. According to the hypothesis, trigeminal neuralgia results from specific abnormalities of trigeminal afferent neurons in the trigeminal root or ganglion. Injury renders axons and axotomized somata hyperexcitable. The hyperexcitable afferents, in turn, give rise to pain paroxysms as a result of synchronized afterdischarge activity. The ignition hypothesis accounts for the major positive and negative signs and symptoms of trigeminal neuralgia, for its pathogenesis, and for the efficacy of treatment modalities. Proof, however, awaits the availability of key experimental data that can only be obtained from patients with trigeminal neuralgia.

Gabapentin Supplemented With Ropivacain Block of Trigger Points Improves Pain Control and Quality of Life in Trigeminal Neuralgia Patients When Compared With Gabapentin Alone

“…53 The importance of this effect in GBP action is not known as ACs that act synaptically (eg, barbiturates) are largely ineffective as analgesics. 15 According to the ''ignition hypothesis'' of TN, 15,54,55 pain paroxysms begin with discharges in a small set of trigeminal primary afferents resulting from spontaneous activation or after cutaneous trigger point stimulation. Crossed-afterdischarge then excites nonstimulated neighbor fibers through a ''windup'' mechanism that selfsustains fiber activity beyond the original focal fiber discharge.…”

A prospective study of 39 patients with trigeminal neuralgia treated with percutaneous balloon compression

“…Trigeminal neuralgia (TN) is the most common type of facial neuralgia with incidence of 26.8/100,000 person-year 1 . It is considered to be one of the most painful conditions to affect patients 2 .…”

Neuralgia induzida por cavitação osteonecrótica

“…Neuromodulators significantly improve pain in the beginning, and there may be pain latency periods. There are cases where pain returns without apparent reasons [25][26][27][28][29][32][33][34][35] . Glossopharyngeal neuralgia is similar to trigeminal neuralgia being differentiated by the anatomic site.…”

“…Studies 3,19 have proposed the following diagnostic criteria: pain in the alveolar bone in regions innervated by the trigeminal nerve and temporary pain relief when the region is submitted to anesthetic block. NICO also interferes with quality of life and may be easily mistaken for other neuropathic and / or deep somatic musculoskeletal and visceral diseases 4,8,9,[25][26][27][28][29] .…”