Neurovascular Compression Syndromes

Abstract

Neurovascular compression syndromes are a group of pathological conditions caused by vascular compression of cranial nerves in the cerebellopontine angle. These syndromes include trigeminal neuralgia, hemifacial spasm, disabling positional vertigo, tinnitus, and glossopharyngeal neuralgia. Historical Background: In 1773, Fothergill gave a clear description of trigeminal neuralgia while in 1888 Gowers described hemifacial spasm as a disease entity. In the 1930s Dandy first observed abnormal contacts between vessels and the trigeminal nerve in patients suffering from trigeminal neuralgia. In the 1940s, Sunderland observed abnormal neurovascular relationships in the brains of elderly cadavers. In the 1960s Gardner performed vascular decompression in patients with hemifacial spasm and trigeminal neuralgia. In the 1970s and in the 1980s, Jannetta and Moller greatly contributed to clarifying the concept of neurovascular compression and to developing definitive microsurgical procedures aimed at treating these symptoms. Surgery: Microvascular decompression is a surgical procedure used to separate the offending vessel(s) from the affected cranial nerve. Usually, a piece of Teflon is placed between the blood vessel and the nerve to prevent recontact. Treatment of vascular compression syndromes by microvascular decompression is effective with a consistently high cure rate. In Parma and in Marseille the decompression was performed via a minimally invasive retrosigmoid approach in the majority of cases. The use of the endoscope (Magnan, 1993) allows a safe and reliable identification of the offending vessel(s) and confirms the correct position of Teflon before closure. The enlarged middle cranial fossa approach was used in Parma to treat hemifacial spasm. A chemical product called mesna facilitates elevation of the compressing vascular loop from the affected cranial nerve. To perform the so-called “chemically assisted dissection” (CADISS®) we use the common mechanical instruments opportunely modified in order to deliver the mesna solution on the tip of the instruments and, therefore, directly in contact with the tissues to be detached, thus reducing its inappropriate diffusion. The authors will present the surgical technique of microvascular decompression and the results obtained in 500 decompression procedures.