Demonstration of neurovascular compression in XXXX with magnetic resonance imaging. Comparison with surgical findings in 52 consecutive operative cases.

@entity1 @entity5108 @entity4254 @entity2850 @entity158 @entity2287 @entity15
Until recently, the inability to demonstrate neurovascular compression of the trigeminal nerve preoperatively resulted in surgery being offered only in cases of severe @entity4254 ( @entity4254 ), frequently after a prolonged trial of medical treatment and following less invasive procedures, despite the fact that posterior fossa microvascular decompression gives long-term @entity158 relief in 80% to 90% of cases. To assess whether @entity2850 of the nerve could be demonstrated preoperatively, high definition magnetic resonance tomographic angiography (MRTA) was performed in 50 consecutive @entity1 , five of whom had bilateral @entity4254 , prior to posterior fossa surgery. The imaging results were compared with the operative findings in all @entity1 , including two @entity1 who underwent bilateral exploration. Vascular compression of the trigeminal nerve was identified in 42 of 45 @entity1 with unilateral symptoms and on both sides in four @entity1 with bilateral @entity4254 . In the last @entity1 with bilateral @entity4254 , neurovascular compression was identified on one side, and on the other side the compressing superior cerebellar artery was separated from the nerve by a sponge placed during previous surgery. There was full agreement regarding the presence or absence of neurovascular compression demonstrated by MRTA in 50 of 52 explorations, but MRTA misclassified four vessels compressing the trigeminal nerve as arteries rather than veins. In two cases, there was disagreement between the surgical and MRTA findings. In the first of these cases, surgery revealed distortion of the nerve at the pons by a vein that MRTA had predicted to lie 6 mm remote from this point. In the second @entity1 , venous compression was missed; however, this @entity1 was investigated early in the series and did not have @entity2287 -enhanced imaging. In nine cases, MRTA correctly identified neurovascular compression of the trigeminal nerve by two arteries. Moreover, MRTA successfully guided surgical reexploration in one @entity1 in whom a compressing vessel was missed during earlier surgery and also prompted exploration of the posterior fossa in two @entity1 with @entity15 and one @entity1 with @entity5108 , in whom neurovascular compression was identified preoperatively. It is concluded that MRTA is an extremely sensitive and specific method for demonstrating @entity2850 in @entity4254 . As a result, open surgical procedures can be recommended with confidence, and microvascular decompression is now the treatment of choice for @entity4254 at the authors' unit. They propose MRTA as the definitive investigation in such @entity1 in whom surgery is contemplated.
