Results of treatment of trigeminal neuralgia by microvascular decompression of the Vth nerve at its root entry zone.

Eighty five patients suffering from trigeminal neuralgia resistant to medical therapy underwent surgical treatment for relief of pain at the Department of Neurosurgery University Alexander Hospital Sofia from 1981 until 1997. Microvascular decompression at the root entry zone of the V(th) nerve has been performed using the technique of Jannetta. The operative exploration of the parapontine root entry zone disclosed neurovascular conflicts in 87.1% of the cases. They represented displacement and/or distortion, sometimes pressure grooves, discoloration, altered vascularity of the V(th) nerve. The analysis of early postoperative results have shown an excellent outcome in 90.6% of the cases, good in 3.5% and poor in 2.4% with mortality of 3.5% early in these series when no postoperative monitoring was available. The follow up study one year after surgery revealed 90.2% excellent and 3.7% good results and poor outcome and recurrences in 6.1% of the cases. Patients with long lasting trigeminal neuralgia, previous destructive procedures, venous compression, lack of convincible evidences for neurovascular conflicts had less favorable outcome or recurrences. In the last years partial sensory rhizotomy was performed in cases when no neurovascular conflicts were found out. Patients with unquestionable arterial compression leading to displacement associated with distortion and pressure grooves had excellent outcomes. Early recurrences were associated with missed pathology at the entry zones. During reexplorations for late recurrences new arterial compression was found in less than half of the cases.