LAUSR

BACKGROUND Arteriovenous malformations (AVMs) of the posterior fossa are demanding lesions that often present with rupture. Studies including outcome analyses in surgically operated patients with ruptured infratentorial AVMs are scarce. Certain anatomic and demographic features have shown associations with postoperative outcomes. METHODS Eighty-six patients with infratentorial AVM were collected from our AVM database. Fifty-four patients were admitted from 1990 onward, and their demographic, lesion, and treatment characteristics were analyzed. The cohort was further refined to 38 consecutive patients with surgically treated ruptured infratentorial AVM admitted to our center between 1990 and 2014, and statistical analyses of factors influencing outcomes were conducted. RESULTS Twenty-seven patients (69%) had a favorable outcome at early follow-up and 24 (67%) had a favorable outcome at final follow-up. Factors associated with poor outcome in early recovery on univariate analyses were deep venous drainage of the lesion (odds ratio [OR], 5.3; P = 0.037) and high Hunt & Hess score (P = 0.003). In the multivariate model, independent predictors for poor outcome were deep venous drainage (OR, 14.5; P = 0.010) and older age at admission (OR, 1.06; P = 0.028). The sole independent predictor for poor outcome at last follow-up was deep venous drainage (OR, 5.00; P = 0.046). The total follow-up time was 370 person-years. CONCLUSIONS AVMs of the posterior fossa usually present with rupture and thus require prompt clinical treatment. The majority of surgically treated patients recover favorably. Our data show that venous drainage patterns have the greatest influence on the patient's postoperative condition. Other influencing factors include the severity of hemorrhage and patient age at admission.