Risk of hemorrhage in patients with untreated Spetzler-Martin grade IV and V arteriovenous malformations: a long-term follow-up study in 63 patients.

BACKGROUND: Treatment of Spetzler-Martin Grade IV and V brain arteriovenous malformations (ie, high-grade AVMs) carries a high risk of morbidity and even mortality. However, little is known about the behavior of these lesions if left untreated. OBJECTIVE: To investigate the natural history of patients with high-grade AVMs. METHODS: Patients with untreated high-grade AVMs admitted to our center between 1952 and 2005 were followed from admission until death, AVM rupture, or initiation of treatment. Rates of rupture and various risk factors were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards models. Functional outcome was assessed 1 year after possible AVM rupture using the Glasgow Outcome Scale. RESULTS: Sixty-three patients with a mean follow-up time of 11.0 years (range, 1 month to 39.6 years) were identified. Twenty-three patients (37%) experienced a subsequent rupture. The average annual rate of rupture was 3.3%. In patients with hemorrhagic presentation, the annual rate was 6.0%, compared to 1.1% in patients with unruptured AVMs (P = .001, log-rank test; hazard ratio, 5.09 [1.40-18.5, 95% CI]; P = .013, multivariate Cox regression model). One year after the first subsequent rupture, 6 patients (26%) had died, and 9 (39%) had moderate or severe disability. CONCLUSION: Untreated high grade AVMs presenting with hemorrhage have a significant risk of subsequent rupture, and their rupture carries a higher risk of case fatality and permanent morbidity than AVMs in general. The risks associated with their treatment should be appraised in light of perilous natural history.

Microsurgical principles for anterior circulation aneurysms.

Microneurosurgical techniques introduced by Prof. Yasargil have been modified by the senior author (JH) when treating more than 4,000 patients with aneurysms at two of the Departments of Neurosurgery in Finland, Kuopio and Helsinki, with a total catchment area of close to three million people. This experience is reviewed, and the treatment of anterior circulation aneurysms by simple, fast, normal anatomy preserving strategy is presented.Most of the aneurysms of the anterior circulation are treated by using the lateral supraorbital approach, a less invasive, more frontally located modification of the pterional approach. To avoid extensive skull base surgery, a slack brain is needed and achieved by experienced neuroanesthesia and by surgical tricks for removal of CSF.Diagnosis of cerebral aneurysm before rupture improves treatment results more than any technical advances. Until this is realized, we continue to treat cerebral aneurysms by simple, fast, preserving normal anatomy-strategy, which has served our patients well.Patients with cerebral aneurysms should be treated at specialized neurovascular centers.

Present state of microneurosurgery of cerebral arteriovenous malformations.

Microneurosurgical excision is known to be the definitive treatment for brain arteriovenous malformation (AVMs). The most important factors governing the operability of an AVM are location, size, age of the patient, and the neurosurgeon's and team's experience. We present in this review the surgical experience of the senior author (JH) in microneurosurgical treatment of brain AVMs. This consists of the following steps: (1) accurate preoperative embolization; (2) optimal selection of the surgical approach; (3) accurate definition and preservation of the normal arterial vessels of passage; (4) temporary clipping of the feeding arteries; (5) a special method of coagulation called "dirty coagulation" of the deep small difficult vessels inside apparently normal brain around the AVM; (6) removal of all AVM; (7) meticulous hemostasis; (8) intra- and postoperative digital subtraction angiography (DSA); (9) clinical and radiological follow-up. These steps are not possible in AVMs lying entirely within central eloquent areas. Nine out of ten small- and medium-sized arteriovenous malformations (AVMs) are suitable for direct surgery, but surgical complications increase drastically with the size of the AVM. Nevertheless, the actual results of combined treatment with preoperative Onyx embolization followed by microsurgery have decreased these risks.

Ectopic recurrence of craniopharyngioma along the surgical route: case report and literature review.

We present a 22-year-old woman with an ectopic recurrence of a craniopharyngioma. The patient presented first with a visual field deficit, and a craniopharyngioma was removed via an interhemispheric transcallosal approach. Magnetic resonance imaging (MRI) performed at 1 month, and then at 1 year after surgery showed complete removal of the lesion. However, at 4 years, MRI showed the presence of a small tumor in the right medial frontal lobe attached to the falx and along the previous surgical route. We present possible explanations for the ectopic recurrence and literature review.