The historical evolution of microvascular decompression for trigeminal neuralgia: from Dandy's discovery to Jannetta's legacy.

Although the symptoms of trigeminal neuralgia (TN) have been well described throughout the history of medicine, its etiology was initially not well understood by most surgeons. The standard procedure used to treat TN today, microvascular decompression (MVD), evolved due to the efforts of numerous neurosurgeons throughout the twentieth century. Walter Dandy was the first to utilize the cerebellar (suboccipital) approach to expose the trigeminal nerve for partial sectioning. He made unique observations about the compression of the trigeminal nerve by nearby structures, such as vasculature and tumors, in TN patients. In the 1920s, Dandy unintentionally performed the first MVD of the trigeminal nerve root. In the 1950s, Palle Taarnhøj treated a TN patient by performing the first intentional decompressive procedure on the trigeminal nerve root solely through the removal of a compressive tumor. By the 1960s, W. James Gardner was demonstrating that the removal of offending lesion(s) or decompression of nearby vasculature alleviated pressure on the trigeminal nerve and the pain associated with TN. By the 1990s, Peter Jannetta proved Dandy's original hypothesis; he visualized the compression of the trigeminal nerve at the root entry zone in TN patients using an intraoperative microscope. In this paper, we recount the historical evolution of MVD for the treatment of TN.

A history of the Jannetta procedure.

Peter Jannetta was a neurosurgery resident when he proposed the neurovascular compression theory. He built upon the astute observations of Dandy, Gardner, and others who, in the era before the operating microscope, had successfully ventured into the posterior fossa. In 1965, Jannetta performed cranial nerve microdissections for dental students and identified the trigeminal portio intermedia. He proposed that preservation of these sensory fibers may avoid complete facial numbness, and together with Robert Rand developed a subtemporal transtentorial approach for selective rhizotomy for trigeminal neuralgia (TN). Such rash surgery, using an operating microscope, was then forbidden at their University of California, Los Angeles center, so they collaborated with John Alksne to perform the first surgery at Harbor General Hospital. Upon visualizing the trigeminal nerve root, Jannetta was surprised to see a pulsating superior cerebellar artery compressing the nerve and said "That's the cause of the tic." He also hypothesized that alleviating the observed vascular cross-compression may be curative.A few months later, while assessing a patient with hemifacial spasm, Jannetta had the epiphany that this was the same disease process as TN, but instead affecting the facial nerve. The patient consented to what would become Jannetta's first microvascular decompression procedure. The senior faculty members who had forbidden such surgery were away, so the supervising neurosurgeon, Paul Crandall, granted the approval to perform the surgery and assisted. Via a retromastoid approach with the patient in the sitting position and using the operating microscope, Jannetta identified and alleviated the culprit neurovascular compression, with a cure resulting.Jannetta presented his neurovascular compression theory and operative findings to the neurosurgical patriarchy of the time. Elders of the field were generally not inclined to accept the bold speculations of an untested neurosurgeon, and were often determined to discredit the new "cure" of the old diseases. Over decades of refining his surgical technique, documenting the outcomes, and enduring the skepticism he often faced, Jannetta's theory and his microvascular decompression procedure withstood critical analysis and have become recognized as one the great discoveries and advances in neurosurgery and medicine.

Microdescompresión vascular en la neuralgia esencial del trigémino / Microvascular decompression for essential trigeminal neuralgia

Objetivo: Determinar los resultados de la microdescompresión vascular (MDV) en los pacientes con diagnóstico de neuralgia esencial del trigémino no controlados con el tratamiento médico.Métodos: Se realizó un estudio retrospectivo de una serie con neuralgia esencial del trigémino operados por MDV en los Hospitales Clínico Quirúrgicos “Lucía Iñiguez Landín” y “Hermanos Ameijeiras” en el período comprendido de enero del 2001 a marzo del 2016. Se analizaron las variables edad, sexo, ramas neurales afectadas, tipo de compresión vascular más frecuentemente encontrada,complicaciones y recidivas.Resultados: La muestra quedó conformada por 61 pacientes. El sexo femenino fue el más afectado. Mayormente los casos tenían entre50 y 60 años de edad. Las ramas más afectadas fueron la tercera y la asociación de la segunda y tercera rama para un 43,1 (Por ciento) (22) y 21,5(Por ciento) (11) respectivamente. La sepsis de la herida y la fístula de LCR fueron las principales complicaciones con 13,7 (Por ciento) (7) y 9,8 (Por ciento) (5). En el transoperatorio se encontró la compresión vascular en el 60,3 (Por ciento) (31), siempre relacionado con arteria cerebelosa superior. El 88 (Por ciento) (45)de los pacientes operados no presentaron recidiva.Conclusiones: La MDV es efectiva, tanto, para aliviar el dolor, como para preservar las estructuras y funciones neurales, con una mínima aparición de recidivas(AU)

Objective: To determine the outcome of microvascular decompression surgery (MVD) in patients with diagnosis of trigeminal essential neuralgia uncontrolled by medical treatment.Methods: A retrospective study was carried out in a sample of trigeminal essential neuralgia uncontrolled by medical treatment in “Lucía Iñiguez Landín” y “Hermanos Ameijeiras” Clinic-Surgical Hospital between January of 2001 and march 2016. Variables like; age, gender, neural root affect, intraoperative vascular finding, complication and recurrence of pain were analyzed.Results: The sample included 61 patients. There was a female predominance. The most frequent age group was between 50 to 60 yearsold. The trigeminal root more affected was the V2 and the association V2-V3 with 21,5 (Per cent) (11) and 43,1 (Per cent) (22) respectively. The woundinfection and cerebrospinal fluid leak was the main complication with 13,7 (Per cent) (7) and 9,8 (Per cent) (5) We have found intraoperative vascularcompression in 60,3 (Per cent) (31), always related to the Superior Cerebellar Artery. There was not recurrence in 88 (Per cent) (45) patients.Conclusions: The MVD is an effective technique, so much, to relief pain, like to preserve neural structure, with low incidence of pain recurrence(AU)