Intraoperative angiography proves worth for brain aneurysm clipping

A decade-long study of more than 1000 patients has shown strong evidence that the use of angiography during intracranial brain aneurysm surgery is safe and useful to evaluate the surgery's success. It can alter management in more than 12% of cases.

Neurosurgeons have long tried to assess the value of different approaches to rate results of brain aneurysm clipping. Methods include plain visual inspections, sonography, and angiography. Several papers have advocated intraoperative angiography, but the technique remains controversial. Critics cite added procedural time and risk.

A recent study by the National Brain Aneurysm Center in St. Paul, MN, calls all those reasons into question.

"Intraoperative angiography did not add a significant amount of time, did not have any significant complications, and did not raise the risk of infection," said principal investigator Dr. Eric Nussbaum, chair of the NBAC. "Even in cases where everything looked perfect to the surgeons, intraoperative angiography still at times changed the way we did things."

Nussbaum and colleagues reviewed 1025 cases of microsurgery for intracranial brain aneurysm with intraoperative angiography performed at their institution from July 1997 until June 2006. The investigators evaluated all intraoperative angio findings and their impact on surgical treatment, procedure length, and morbidity. They found the technique changed treatment in nearly 10% of patients and helped detect unexpected vascular disease in almost 3%.

Nussbaum presented results of his group's findings at the 2008 American Association of Neurological Surgeons meeting in Chicago.

Intraoperative angiography resulted in clip repositioning or additional clip placement in 96 cases: 64 cases of residual, treatable aneurysm and 32 cases of vascular stenosis. The procedure demonstrated unexpected aneurysm obliteration in 42 cases when the surgeon suspected additional clip placement would be needed. Angio also identified 30 cases of treatable residual aneurysm or vascular stenosis that had been missed or misinterpreted by neurosurgeons.

Case review showed that, in 1997, intraoperative angiography added about half an hour to surgery. By 2006, however, the imaging procedure's mean extra time had been reduced to 10.5 minutes.

Intraoperative angiography proved most critical for large and giant aneurysms, lesions with wide necks needing reconstruction with multiple clips, and those in which a bypass was preferable to a vascular block.

The procedure is not for everybody, Nussbaum said. A team of neurosurgeons and interventional neuroradiologists at the NBAC decides what cases should go to clipping and which should undergo endovascular image-guided coiling instead. Older patients and those with ruptured aneurysms usually undergo the latter procedure.

"Our hope is that people will increasingly appreciate that intraoperative angiography really should be a part of aneurysm surgery," Nussbaum said.

For more information from the Diagnostic Imaging archives:

Whole-body MSCT does 'triple rule-out' of head and neck injuries

Time-resolved MRA revolutionizes imaging

Follow-up care of incidental brain findings draws criticism

Multislice CTA gains edge over DSA for brain aneurysm detection