In 412 patients undergoing surgery for herniated lumbar discs from September 1986 to September 1987 and from January 1988 to July 1989 a microbiological specimen was taken from the intervertebral disc space and from the cover of the operating microscope. Also the tips of the wound drains were examined microbiologically after removal. 17% of the patients had a positive bacteriological culture from their intervertebral disc space; 12% of the specimen from the operating microscope were positive. These results favour the hypothesis that intra-operative contamination of the disc space, in contrast to haematogenous spread, causes spondylodiscitis. On the other hand we saw during this time course only one case of clinical spondylodiscitis, which implies a possible involvement of other predisposing factors such as pre- or perioperative infections or compromised patient immunologically. It is also possible, that the routine application of local antibiotic or antiseptic solutions into the disc space at the end of the operation could decontaminate the operative site and prevent clinical infection despite positive culture findings.

Six endoscopic fenestrations of the 3rd ventricular floor have been performed in patients with stenosis (SAS) of the aqueduct of Sylvius in our institute during the last two years. The endoscopic intraventricular landmarks were the Monro's foramen followed by the mamillary bodies. The fenestration instrument was a monopolar coagulation wire, the dilatation instrument was a balloon catheter. The patients included two newborns and four adults. The two newborns developed a recurrent hydrocephalus after 2 months. The four adults remained well after the operation. The only complication was edema (SIADH syndrome) in one case for 24 hours. Flow sensitised phase MRI showed a mirroring in the prestenotic CSF pulsation curve preoperatively. This, in combination with an increased intraventricular pulsation, is a sign of reduced capacity of the subarachnoid space at the cerebral surface. The postoperative patency of the fenestration with diminished intraventricular pulsation can be demonstrated with ECG retrogated phase MRI. There was a slow and incomplete decrease of the preoperative enlarged ventricular size. This operative method is a low-risk, minimal invasive alternative method to shunt implantation in adults with SAS.

The coincidence of a lumbar disk herniation L4-5 and a neurinoma at the L5 nerve root in a 52-year-old male is reported. The clinical course revealed typical signs of a herniated disk, whereas the tumour was accidentally found by myelography initially performed for the suspected prolapse. Both lesions were removed without complications. The clinical and neuroradiologic aspects of this rare condition are discussed, with special regard to the problems of differential diagnosis. A review of the literature is added.

The experience of 7 operated patients with cavernous haemangiomas (CHa) and of 2 conservatively treated older patients is reported. There was no further postoperative neurological deficit, although 6 of the 7 patients had the CHa in an eloquent cerebral region. Two of the operated patients (22%) had several bleedings before surgery. In these cases seizures and visual field deficits remained. The relatively low rate of complications in our patient group was possible because an exact preoperative localisation helped to avoid a large traumatisation. This is possible with a stereotactic system or directly by CT guided skin marking. Intraoperative ultrasound was necessary in all cases because there was no landmark at the cerebral surface. The CHa was removed by a transsulcal microsurgical operation. A complete removal of the surrounding haemosiderin rim around the angioma seems necessary to avoid further seizures. The used technique has proved to be a simple and safe minimal invasive method.

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