Spinal dural arteriovenous fistulas are the most common type of arteriovenous malformation involving the spinal cord, especially in middle-aged men. We report 21 patients with this malformation who had signs and symptoms of myelopathy. The diagnosis was established by selective spinal angiography in patients whose neurological deficits, myelograms or magnetic resonance tomographies suggested the presence of a spinal arteriovenous fistula. They were treated by microsurgical coagulation of the fistula nidus located in the dura and intradural division of the draining vein. Twenty patients improved neurologically following surgery, one remained unchanged. Complete obliteration of all lesions was verified by intra-operative microvascular Doppler sonography and in 3 cases by postoperative angiography. There were only a few minor and transient complications after surgery: one neurological deterioration where venous thrombosis was suspected, one cerebrospinal fluid accumulation and, in one case a transient wound healing impairment. Two patients had to be operated on again. In one case with difficult localization of a fistula at the L5/S1 level, the fistula was still visible in the postoperative angiogram. In another patient, a spinal epidural haematoma occurred a few hours after surgery. We conclude that microsurgical treatment of spinal dural arteriovenous fistulas is a safe, fast, simple and effective method of treating these lesions. However, recovery after surgical management was often incomplete because the diagnosis was established too late and the patient already presented with severe and long-lasting deficit. Thus, the main problem remains a diagnostic and not a surgical one.

Spinal dural arteriovenous fistulae (DAVF) affect predominantly levels of the lower thoracic and lumbar segments; only 13 cases have been reported of DAVF at the foramen magnum. We present three surgically treated patients with DAVF at the foramen magnum. In none of our three patients could the site of the arteriovenous fistula be suspected from the clinical presentation. The clinical course varied from acutely developing signs and symptoms to a 10-year history of very slowly progressing symptoms. After neuroradiological diagnosis the patients were operated on direct microsurgical disconnection of the arteriovenous shunt via an enlargement of the foramen magnum and a hemilaminectomy of C1. DAVF at the foramen magnum may thus present with slowly to acutely progressing clinical symptoms and signs. Spinal angiographic examination should include the level of the foramen magnum if standard spinal angiography of thoracic, lumbar, and sacral segments is negative in suspected spinal DAVF since the nidus of the shunt can be situated remote from the level of neurological disorder. DAVF at the foramen magnum can be treated very effectively and with minimal surgical trauma by direct microsurgical disconnection of the shunt. This surgical procedure is indicated if embolization with glue is not possible or is unsuccessful.

Six patients with a dural arteriovenous fistula (DAVF) of the floor of the anterior cranial fossa underwent microsurgical treatment. Two of them were operated using a conventional frontobasal approach, and four using an interhemispheric approach. The interhemispheric approach offers the advantages of sparing the frontal sinus, minimizing frontal lobe retraction, and providing a visual angle perpendicular to the floor of the anterior fossa and an excellent view of the fistula located on the cribriform plate at the level of the foramen caecum. Using the interhemispheric route, the malformation was occluded in all the cases by dividing the vascular connection between the dura of the cribriform plate and the intradural draining vein. There were no complications related to the surgical procedure. This route avoids some disadvantages of the more frequently reported frontobasal approach. It is therefore a recommendable alternative for the management of frontal DAVFs.

After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.

Object. Complete resection is the optimal treatment for atypical meningiomas (AMs) but its feasibility depends on the tumor site. The object of this study was to assess the effect of gamma knife surgery (GKS) on AM. Methods. In 15 patients 21 AMs were treated by GKS. Four patients had residual lesions and 10 patients had recurrent tumors after one or more microsurgical interventions. Three patients were treated twice with GKS because of tumor tissue outside the treatment volume, either at the margin or at a distant location. The median clinical and neuroimaging follow-up period was 35 months (range 21–67 months). Ten tumors shrank 6 to 12 months after GKS, 10 remained stable, and one grew. Between 18 and 36 months after GKS, four patients had a distant recurrence, and two had a margin recurrence. In one of these cases, an additional local recurrence was demonstrated 1 year later, and the patient underwent standard radiotherapy. No patient suffered persistent adverse effects after radiosurgery. Conclusions. After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.