Characterization of the cerebral blood flow response to balloon deflation after temporary internal carotid artery test occlusion

Intraoperative Computed Tomography (CT) for Treating Giant Carotid Intracavernous Aneurysms

Background

Giant carotid intracavernous aneurysm refers to those lesions larger than 2.5 cm and derived from a cavernous segment, accounting for about 30% of all intracranial tumors. Dynamic CT perfusion imaging (PCT) is a common method recently employed to evaluate cerebral perfusion. This study investigated the efficacy and clinical application of intraoperative CT in the surgery for giant symptomatic carotid intracavernous aneurysm.

Material/Methods

A retrospective analysis was performed on 23 cases with giant symptomatic carotid intracavernous aneurysm. BTO testing was performed before surgery. Differential treatments were performed based on the condition of aneurysm, and some patients received intraoperative PCT. Postoperative anti-coagulation was given with DSA or CTA follow-up examinations at 3–6 months, 1 year, and 2 years after surgery.

Results

A total of 17 patients received aneurysm isolation coupled with high-flow bypass surgery. Among those, 9 developed early-onset neurological function after surgery, with gradual recover within 6 months. One coma patient died 25 months after discharge. One patient had aneurysm isolation with clapping of anterior communicating artery, and the other 5 cases received artery clapping only. In those patients, 4 had improvement at early phase, while 1 patient had numbness of the oculomotor nerve. Six patients received surgery in the CT room, including 5 cases with single proximal ligation of the internal carotid artery plus 1 aneurysm isolation combined with high-flow bypass surgery.

Conclusions

Intraoperative PCT can provide objective evidence and effective evaluation of cerebral perfusion.

Impact of cervical internal carotid clamping and radial artery graft bypass on cortical arterial perfusion pressure during craniotomy

Strategic cervical internal carotid occlusion is employed either temporarily or permanently in various neurosurgical procedures. The aim of the present study was to assess changes in cortical arterial pressure during cervical internal carotid cross-clamping before and after the placement of radial artery (RA) graft bypass in the treatment of complex carotid artery aneurysms. Perfusion pressure of the middle cerebral artery (MCA) was assessed in 22 patients with complex carotid aneurysm treated with RA graft bypass. Regional cerebral blood flow was assessed postoperatively using single-photon computed tomography. Mean cortical blood pressure (mcBP) was found to be 48.2 ± 24.2 and 97.0 ± 24.0 % of baseline after clamping the cervical internal carotid artery and opening the RA graft bypass, respectively. Cerebral perfusion pressure estimated by the mcBP failed to sustain a critical limit of greater than 70 mmHg under craniotomy in 16 out of 20 (80 %) patients. There was an inverse correlation in mcBP between the baseline and after the placement of the RA graft bypass (r = 0.66, P < 0.005). Postoperative regional cerebral blood flow in the MCA territory on the ipsilateral side of the aneurysm was 97 ± 7 % of that of the contralateral side after internal carotid artery (ICA) ligation combined with RA graft bypass. Substantial pressure reductions in cerebral cortical arteries were observed during the cervical internal carotid cross-clamping. Perfusion pressure in peripheral cortical arteries after the placement of the RA graft bypass was comparable to the state before ICA clamping.

Evaluation of Balloon Occlusion Test for Giant Brain Aneurysms under Local Anaesthesia

We describe our experience in balloon test occlusion for giant carotid or basilar aneurysms under hypotension. Twenty-four patients underwent balloon test occlusion (BTO) during the year 2008. Only patients showed absence of any neurological deficits after 20 minutes under normal tension then another 20 minutes under hypotension were considered tolerable for occlusion of the parent artery. Of the 24 patients, four (16.67%) had deficits at normal tension and two (8.33%) had deficits at hypotensive phase. None of the 18 (75%) patients who clinically tolerated test occlusion and had parent artery sacrifice show any complication at follow-up period of two years. Two patients with clinical intolerability underwent carotid artery sacrifice after STA-MCA bypass without sequelae. Balloon test occlusion with hypotension is a useful, competent and simple technique in the evaluation of tolerance to parent artery occlusion in case of giant and complex intracranial aneurysms.

Extracranial-intracranial bypass to reduce the risk of ischemic stroke in intracranial aneurysms of the anterior cerebral circulation: a systematic review

BACKGROUND AND PURPOSE

If clip application or coil placement for treatment of intracranial (IC) aneurysms is not feasible, the parent vessel can be occluded to induce thrombosis of the aneurysm. In the case that such an occlusion cannot be tolerated without subsequent sequel, the additional construction of an extracranial (EC)-IC bypass is needed for sufficient ipsilateral revascularization. Hitherto, the effectiveness of this combined treatment option was not investigated in a controlled randomized trial or in a review. The aim of the current report was to analyze clinical effectiveness of EC-IC bypass for cerebral revascularization in patients with Hunterian ligation in case of otherwise untreatable aneurysm of the anterior cerebral circulation. Special reference was given to different hemodynamic subgroups.

METHODS

A computerized database search was conducted from November 1985 to November 2002 using MEDLINE, relevant Internet sources, and full-text journal articles using appropriate indexed terms. Journal of Neurosurgery, Neurosurgery, Acta Neurochirurgica, and Stroke were manually searched for the period November 1985 to November 2002 and checked reference lists of all relevant articles for additional eligible studies. Language restriction was done for English, French, and German. Reports dealing with EC-IC bypass surgery for cerebral revascularization in case of aneurysm of the anterior cerebral circulation were reviewed when appropriate. Studies were included that contained evaluable data on clinical state, preoperative and postoperative hemodynamic state, surgical outcome, and follow-up. A statistical analysis was performed for different outcome parameters and clinical effectiveness in the included studies.

RESULTS

Overall, 20 studies were included, each with a study quality of 0-1. The postoperative outcome related to death or stroke depended mainly on preoperative hemodynamic subgroups (cerebral blood flow [CBF]/cerebral blood volume [CBV]; oxygen extraction fraction [OEF]). The final functional status was worse the more CBF/CBV ratio and OEF increased. Perioperative risk for death (0.8%) or stroke (1.5%) during the first month after operation was similar to the death or stroke rate during the following 2 to 12 months after operation. Neurologic function was improved over the preoperative state in 74% of the patients and was unchanged in 9%. The modified Rankin scale score was postoperatively 0 to 1 in 81% and 2 in 6% of the patients. Long-term patency was excellent, with 2.3% failure rate per year after the first year after surgery. There was no de novo aneurysm formation in the follow-up.

CONCLUSION

Neurologic function and subsequent stroke attributable to hemodynamic insufficiency in patients with otherwise untreatable IC aneurysm improves significantly by EC-IC bypass surgery if the brain area corresponding to the impaired neurologic function remains viable. The hemodynamic parameters observed for patients who experience improved neurologic function or diminished stroke risk profile after EC-IC bypass surgery contain both significantly elevated OEF and CBF/CBV. Therefore, hemodynamic state represents an important indicator for EC-IC bypass surgery. The large amount of data leads to narrow stroke with no significant heterogeneity, and the overall results are, therefore, likely to be statistically robust.

Giant mycotic aneurysm of the internal carotid artery in a child: endovascular treatment

We present a case of a giant mycotic aneurysm of the left internal carotid artery in a child, the result of direct extension of a deep neck space infection. This lesion is life threatening and may put the patient at risk of unwarranted biopsy or drainage if not recognized. Diagnosis and treatment planning rely heavily on cross-sectional imaging, and angiography is frequently necessary. This case is unique for two reasons: (1) we present for the first time the MRI findings and (2) we describe an alternative to surgical ligation -- neurointerventional embolotherapy. Minimally invasive transcatheter embolization was successfully performed on our patient to occlude the abnormal left internal carotid artery segment.