The treatment of large, high-flow cerebral arteriovenous malformations (AVMs) is one of the most difficult operations which a neurosurgeons will encounter, because of the complex surgery and the postoperative effects on the brain. We evaluated 25 patients with AVMs who underwent surgical resection. They were classified into three groups for the purpose of determining a therapeutic approach. They comprised of 9 cases with small AVMs (<3cm), 2 cases of medium AVMs (3 to 6cm) and 14 cases of large AVMs (>6cm). Patients were investigated with contrast-enhanced computed tomography (CECT) and magnetic resonance (MR) imaging, 123I-IMP single photon emission computed tomography (SPECT) studies of cerebral flow and cerebral vasodilatory function, intraoperative Laser Doppler flowmetry, and conventional angiography.
SPECT imaging performed on the first postoperative day showed marked hyperperfusion in the brain tissue surrounding the resected nidus, and these regions were normal on images on the 7th postoperative day. Laser Doppler flowmetry showed sudden, and marked increase in CBF immediately following placement of temporary clips on the main feeding artery. Angiograms done 7-14 days following surgery showed a stagnating artery, fragile vessel, and a prolonged circulation time. Our results indicate that pre- and postoperative SPECT study, especially a dynamic SPECT study done on the first postoperative day, was the most useful examination for ascertaining the postoperative NPPB.
