Non-saccular aneurysms of the supraclinoid internal carotid artery trunk causing subarachnoid hemorrhage: acute surgical treatments and review of literatures

Abstract

Chondrosarcoma (CSA) of the skull base (SB) is an uncommon, slowly growing, neoplasm comprising approximately 0.1% of all intracranial tumors and 6% of SB lesions. Even though its growth is slow, CSA is a potentially lethal tumor. The therapeutic approach to CSA of the SB is still controversial and clinical experience is limited because of the relative rarity of this tumor. The use of proton therapy (PT) after maximal surgery is widely accepted, but there are no controlled studies demonstrating the need of PT and its superiority in comparison to radiotherapy with photons. We conducted a systematic review of the scientific literature published during the period between January 1980 and June 2008 on data regarding irradiation of CSA of the SB with PT and a series of inclusion criteria. During August 2008, two independent reviewers (M.A. and D.A.), by applying the key words "skull base", "chondrosarcoma", and "proton therapy" selected those studies from the PubMed database in which a minimum of ten patients received palliative, radical, or postoperative irradiation with protons and which furnished a minimum of 24 months of follow-up. Forty nine reports were retrieved. There were no prospective trials (randomized or nonrandomized) but just nine uncontrolled single-arm studies for PT mainly related to advanced and frequently incompletely resected tumors. According to the inclusion criteria, only four articles, reporting the most recent updated results of the publishing institution, were included in the analysis providing clinical outcomes for 254 patients in total. Therapeutic approach to CSA of the SB has traditionally relied on surgical control. Radiation therapy has demonstrated to be a valuable modality for local control in the postoperative setting or in advanced/inoperable cases treated with definitive intent. The use of PT following maximal surgical resection shows a very high probability of medium- and long-term cure with a relatively low risk of significant complications.

The importance of preoperative diagnosis of blister aneurysms

“…Instead, an inherent collagen defect may significantly contribute to aneurysmal formation [22]. Shimizu et al propose that areas of high ICA curvature are more susceptible to atherosclerosis and internal elastic lamina injury [22]. In a simulated study of shear stress on 3D BA reconstructions, low stress was noted within the BA.…”

“…As BA typically arise in regions remote from vessel branching points, high shear stress is not believed to be the principal pathogenic mediator. Instead, an inherent collagen defect may significantly contribute to aneurysmal formation [22]. Shimizu et al propose that areas of high ICA curvature are more susceptible to atherosclerosis and internal elastic lamina injury [22].…”

Morphological aspects of blister aneurysms and nuances for surgical treatment

“…All aneurysms in our series and those we found in the literature could be readily classified into 1 of these 4 types (Table 2). 1,2,4,6,7,9,10,[12][13][14][18][19][20][23][24][25][26][27][28][29][31][32][33]35,[39][40][41][42][43][44]47,[49][50][51][52]57 Each type presented distinctive surgical pitfalls, which required a different clip placement technique.…”

“…Also generally, patients with blister aneurysms were younger than patients with berry aneurysms. 47 In 12 cases, the first angiogram was negative or inconclusive, requiring a second angiogram 3 to 14 days later, revealing the presence of an aneurysm or a change in its morphological appearance. In all 61 cases, we were able to match the aneurysms according to our classification of 4 subtypes.…”

“…16,21,22,47,55 However, occlusion of a major vessel in an acute stage following subarachnoid hemorrhage is associated with poor prognosis. 33 Also, a balloon test occlusion may be difficult to assess when the patient is suffering from the neurological effects of a ruptured aneurysm.…”