Microneural decompression operations in the treatment of some forms of cranial rhizopathy.

Since 1985 147 explorations of the cerebellopontine angle have been performed in patients with trigeminal neuralgia (TN), in 26 patients with hemifacial spasm (HFS), and in the craniospinal region in 22 patients with spasmodic torticollis (ST). In TN in 128 (87%) patients vascular compression of the fifth nerve was found, in 8 (5%)--compression by a tumour, but in 11 (7.5%) nerve compression was not observed. In 92 (63%) patients only microvascular decompression (MVD) was performed, but in 36 (24.5%)--MVD and partial sensory rhyzotomy (PSR). Following MVD pain was absent or insignificant in 121 (92%) after MVD and PSR in all 36 patients, recurrence was observed in 5 (5%) cases. MVD was inefficient in case of atypical TN. Two patients died. As diagnostic criteria for vascular decompression pre-operative and intra-operative recording of short latency somatosensory evoked potentials of the fifth nerve were used. In all HFS patients vascular compression of the facial nerve roots has been established. Following MVD spasm was absent in 18 (69%) patients, 6 (23%) patients had significant improvement, but in two cases (8%) the improvement was insignificant. During craniospinal exploration in ST the accessory nerve was compressed in 6 cases by artery, in 6 patients only by cross-sectional adhesions, in two by a hypertrophied dentate ligament and in 3 cases by small neurinomas of the XI th nerve. Following microdecompression of the accessory nerve (without roots transsection) 17 (77%) patients fully recovered or had significant improvement. One of the 4 patients with insignificant improvement had previously undergone stereotactic surgery, but the other had retrocollis. In one patient with neurinoma of the XI nerve recurrence was observed, no significant improvement was noted in the other two patients.