Trigeminal Neuralgia Involving All Three Branches Of Trigeminal Nerve Treated By Peripheral Neurectomy: An Interesting Case Report

摘要

Trigeminal neuralgia is a well known facial pain syndrome characterized by excruciating, paroxysmal, shock like pain attacks located in the somatosensory distribution of the trigeminal nerve. It occurs in both genders (with a slight female predominance), and the diagnosis is most common over age 50. Treatment options are varied for this condition ranging from medical therapy to invasive surgical procedures. No treatment modality to date is totally recurrence free. Peripheral neurectomy is one of the oldest surgical modalities which is least invasive and with few complications. We present an interesting case of a 53 year old male patient with trigeminal neuralgia simultaneously involving all the three branches ipsilaterally. Following neurectomy of all the three involved branches, the patient was free of recurrence in a five year follow – up period. Introduction Trigeminal neuralgia or tic douloureux is a debilitating syndrome consisting mainly of unilateral short bursts of lancinating pain in one or more branches of the trigeminal nerve1. The first detailed account of trigeminal neuralgia was given by John Fothergill in 1773 when he presented a paper in the Medical Society of London2.According to the ICHD - II criteria (International Classification of Headache Disorders II), classic trigeminal neuralgia is the most common idiopathic form of disorder and is defined as “a unilateral disorder characterized by brief electric shock-like pains, abrupt in onset and termination, limited to the distribution of one or more divisions of trigeminal nerve. Pain is commonly evoked by trivial stimuli including washing, shaving, smoking, taking and/or brushing the teeth (trigger factors) and frequently occurs spontaneously”3. In individual patients, the pain attacks are stereotyped, recurring with the same intensity and in the same distribution. The second and third trigeminal divisions are more often involved4. Right side of the face is more involved than the left5. The etiology of trigeminal neuralgia is widespread from no specific reason – known as “idiopathic form” to space – occupying lesions within the posterior cranial fossa. The current opinion is in favour of a “neurovascular conflict”: An artery, most often a loop of the superior or antero-inferior cerebellar artery, has an offending contact with the trigeminal nerve root, which results in localized demyelination and ectopic triggering of neuronal discharges6. The diagnosis is made on the basis of typical history and the exclusion of secondary cases7. Treatment of trigeminal neuralgia is both through medical therapy and surgical intervention, with each one having its own merits and demerits. Among the surgical procedures, neurectomy is the oldest modality of intervension8. In the centers where the facilities are not available or the patient is not fit for major neurosurgical procedures like microvascular decompression or radiofrequency thermocoagulation, neurectomy has its role in the treatment of trigeminal neuralgia. This paper highlights a typical case of idiopathic trigeminal neuralgia simultaneously involving all the three divisions of the trigeminal nerve. Peripheral neurectomy was performed under local anesthesia for all the three branches i.e., supra-orbital ,infra-orbital and mental. The patient was followed regularly for a 5 year period and was free of any recurrence. Case Report A 53 year old male patient was referred to our center by a general dental practitioner with acute bouts of severe pain on the right side evoked by perioral triggers. He was under medical therapy (Tab.Carbamazepine 200 mg, twice daily) for the past 8 months. Diagnosis was confirmed at our center by asking the patient to stop carbamazepine for a period of 3 days and by giving diagnostic test blocks of local anesthesia. Comprehensive head and neck examination with special attention to the trigeminal sensory system and cranial nerves was also performed. There was no sensory deficit involved. Odontogen