Microvascular decompression (MVD) has come to stay as an effective way of treating hemifacial spasm. But it remains to be seen how much each of the electrophysiological monitoring techniques (intra-operative) are contributing to its increased efficacy. Their role as indicators for re-exploration or recurrence is to be evaluated with more studies. We have used the lateral spread response in those patients who had distinctly abnormal recording on the ipsilateral side, studied the intra-operative changes during MVD and correlated with the outcome of surgery. 38 patients operated for HFS, were selected for intra-operative monitoring of abnormal muscle responses. In 17 patients, there was persistence of abnormal muscle responses in the immediate postoperative period and only 6 of them had mild HFS. Two of 21 patients who had disappearance of abnormal responses had persistent mild HFS; but in all cases, the HFS disappeared within 3 months. So we found that the intra-operative recording was really not reliable in predicting the immediate postoperative outcome. However the outcome at 3 months suggested that waiting for some time before re-exploration is a better option, especially if the HFS had become mild.

The syndrome of the supplementary motor area (SMA) is not well recognized and its features can easily be confused with pyramidal weakness. The authors describe the SMA syndrome in six patients who underwent surgery for tumours located in the SMA, three in the dominant and three in the non-dominant hemispheres. All of them underwent complete resection of the anatomically described SMA, with partial (n = 4) or total resection (n = 2) of the tumour. In the postoperative period, all these patients exhibited reduction of spontaneous movements and difficulty in performing voluntary motor acts to command in the contralateral limbs, although the tone in the limbs was maintained or increased. The function of these limbs in serial automatic motor activities (for example, dressing and walking) was, however, relatively unaffected. Speech deficits were seen in only one of three patients with the dominant SMA syndrome. Besides a severe impairment of volitional movements, the salient features of the deficits in this syndrome are hemineglect and dyspraxia or apraxia involving the contralateral limbs. All patients recovered their motor functions over varying periods of time ranging from one to a few weeks. Long-term follow-up (median 24 months) in five patients revealed complete return of function in the affected limbs. It is important to recognize the entity of the SMA syndrome and differentiate it from the deficits that result from operative damage to the motor cortex as the deficits associated with the former are likely to recover almost completely over a short period of time.

Chordomas constitute <5% of vertebral column tumours and a third of these arise in the upper cervical spine and tend to be clival - usually midline, with occasional eccentric extension. We report a case of cervical chordoma presenting as a lateral neck mass and discuss its origin, diagnosis and management.

We report a case of a cystic lesion in the left cerebellopontine (CP) angle cistern. The magnetic resonance (MR) imaging features closely resembled an epidermoid inclusion cyst, and was interpreted as such. However, at surgery and on histopathological examination the lesion was found to be a cysticercus cyst. It may be impossible to distinguish between the two by imaging. The MR imaging findings of cysticercosis, epidermoid and other common differentials are discussed.

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