Göran Edner

Natural History of Dural Arteriovenous Shunts

Background and Purpose— Dural arteriovenous shunts with cortical venous reflux or drainage may cause neurological symptoms and death with or without intracranial hemorrhage. Present knowledge about the natural history of these lesions is limited, however. We investigated the incidences of intracranial hemorrhage, progressive dementia syndrome, and death in patients diagnosed in our neurovascular center. Methods— We evaluated the records of 85 patients with dural arteriovenous shunts with cortical venous drainage or reflux hospitalized in our institution from 1978 to 2007. The annual incidences of intracranial hemorrhage, progressive dementia syndrome, and death were calculated. Results— Fifty-three patients did not have an intracranial hemorrhage as the presenting event. One of these patients bled after diagnosis. Thirty-two patients had an intracranial hemorrhage as the presenting event. Three patients bled after diagnosis. One of these patients died. Apart from deficits caused by hemorrhage, no patient reported adverse neurological symptoms. In patients presenting with an intracranial hemorrhage the annual risk for hemorrhage is approximately 7.4% and in those not presenting with a hemorrhage it is approximately 1.5%. Conclusion— The risk of intracranial hemorrhage from a dural arteriovenous shunt with cortical venous drainage is most likely smaller than previously proposed. Presentation with hemorrhage is a risk factor for hemorrhage. The risks of developing neurological symptoms not related to hemorrhage are also less than previously reported.

Stereotactic biopsies and computer tomography in gliomas.

SummaryThis study was carried out in order to obtain data on the relation between tumour structures seen in computer tomograms and the corresponding histopathology and cytology. Nine consecutive patients were studied, and stereotactic biopsies were obtained from sites determined on contrast enhanced computer tomograms. Biopsies were obtained from tumour areas with high and low contrast uptake and from the low attenuating areas surrounding the tumours. The results indicated a close correlation between the microscopical morphology of gliomas and the pattern of the computer tomogram. Biopsy samples from low-uptake central areas contained tumour tissue, necrotic tissue, and in one case a cyst. Biopsies from high-uptake areas typically contained tumour tissue, whereas biopsies from low-uptake surrounding areas contained oedematous non-tumour tissue. For tumour diagnosis biopsies should be obtained from both low and high attenuating tumour areas.

Stereotactic biopsy of intracranial space occupying lesions

SummaryThe results of stereotactic biopsies of intracranial expanding lesions with narrow instruments both prior to and during the CT era are evaluated in 345 patients. Eighty-four cystic lesions were needled and roughly classified. Small, cystic, or solid tumours in anatomically well-defined areas such as the sellar, the third ventricle, and the pineal regions were as easily punctured and classified without as with CT scanning.When larger tumours in different compartments were punctured the biopsy verification rate increased from 55% towards 91% if an enhanced CT investigation was included. A stereotactic biopsy is a fairly safe procedure, yielding in this series a mortality less than 1% and a morbidity of 2.3%.

Neuronavigation for arteriovenous malformation surgery by intraoperative three-dimensional ultrasound angiography.

OBJECTIVE Neuronavigational devices have traditionally used preoperative imaging with limited possibilities for adjustment to brain shift and intraoperative manipulation of the surgical lesions. We have used an intraoperative imaging and navigation system that uses navigation on intraoperatively acquired three-dimensional ultrasound data, as well as preoperatively acquired magnetic resonance imaging scans and magnetic resonance angiograms. The usefulness of this system for arteriovenous malformation (AVM) surgery was evaluated prospectively. METHODS Nine consecutive patients with Spetzler Grade 1 (n = 3), 2 (n = 3), 3(n = 2) or 4 (n = 1) AVMs underwent operation using this intraoperative imaging and navigation system. The system provides real-time rendering of three-dimensional angiographic data and can visualize such projections in a stereoscopic (virtual reality) manner using special glasses. The experiences with this technology were analyzed and the outcomes assessed. Angiographic reconstructions of three-dimensional images were obtained before and after resection. RESULTS Conventional navigation on the basis of preoperative magnetic resonance angiography was helpful to secure positioning of the bone flap; stereoscopic visualization of the same data represented a powerful means to construct a mental three-dimensional picture of the extent of the AVM and the feeder anatomy even before skin incision. Intraoperative ultrasound corresponded well to the intraoperative findings and allowed confirmation of feeding vessels in surrounding gyri and rapid identification of the perinidal dissection planes, regardless of brain shift. The latter feature was particularly helpful because the intraoperative navigational identification of surgical planes leads to minimal exploration into the nidus or dissection at a greater distance from the malformation. Application of the system was thought to increase surgical confidence. In two patients, postresection ultrasound prompted additional nidus removal. Ultrasound angiography seemed to allow some degree of resection control, although its sensitivity was not thought to be sufficient. All AVMs were radically removed without new permanent morbidity. CONCLUSION The complexities of handling the pathological vessels of AVMs were ameliorated by intraoperative three-dimensional ultrasound and navigation because the three-dimensional outline of the vasculature (feeders, nidus, and draining veins) provided a means to adapt resection strategies, define dissection planes, and interpret intraoperative findings. It is difficult to provide a scientifically valid definition of “added value.” However, in our experience, the added confidence and the improved mental image of the lesion that resulted from this technology improved the quality and flow of surgery.

The Stockholm 20-year follow-up of aneurysmal subarachnoid hemorrhage outcome.

OBJECTIVETo assess the clinical and radiological long-term outcome after aneurysmal subarachnoid hemorrhage (SAH) in a defined referral area regarding recurrent SAH and de novo aneurysm formation. METHODSOne hundred and two 1-year survivors after aneurysmal SAH, who were treated at the Neurosurgical Clinic, South Hospital, Stockholm, Sweden, between 1983 and 1985, were followed for 20 years. Forty-nine surviving patients were reevaluated. Hospital records and death certificates were scrutinized for all 53 nonsurviving patients. Clinical history penetration, Mini Mental Status, Rankin Disability Score, and Barthel Index were used to evaluate the outcome. Computed tomographic angiography was used to investigate the cerebral arteries. RESULTSOne hundred and two patients were traced. Fifty-three patients were deceased. One patient had a hospital record of sustaining an aneurysmal SAH from a known but not clipped aneurysm. Three patients had nonaneurysmal intracerebral hemorrhage and two sustained traumatic SAH. There were 49 surviving patients. Six refused follow-up. None of these patients had hospital records of intracranial disease. Three of the 43 remaining patients could not be tested. None of the survivors had experienced a new SAH. Aneurysm base remnants were observed in 1% (eight patients, 790 person-years of follow-up) and de novo aneurysms were observed in 0.9% (seven patients, 790 person-years of follow-up). CONCLUSIONFrom this epidemiological survey of patients with aneurysmal SAH, it was found that none of the patients experienced a recurrent subarachnoid bleed from the treated aneurysm during a 20-year follow-up period. Thus, a routine extreme long-term follow-up period is not necessary. De novo aneurysm formation and possible enlargements of aneurysm base remnants were observed in almost 2% of patients per person year and should, therefore, be subject of a routine, long-term follow-up.

The broken clip

SummaryTwo cases with broken aneurysm-clips are presented.

Bilateral aneurysms of the juxtasellar segment of the internal carotid artery

SummaryThree cases of bilateral aneurysms of the juxtasellar segment of the internal carotid artery concomitant with intrasellar cisternal herniation are presented. Two of the three cases were clinically and neuroradiologically misinterpreted as parasellar tumour when conventional CAT was used. The true diagnosis was established on angiography. By using a dynamic CAT technique the aneurysms would have been distinguished from tumours.