Clipping of a basilar tip aneurysm using hypothermia and cir
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A 52-year-old patient was admitted to hospital with a subarachnoid hemorrhage Hunt and Hess Grade 4. The digital subtraction angiography (DSA) revealed a complex basilar tip aneurysm. At the time of patient’s presentation in our clinic, there was no endovascular therapy option in our institution as our hospital lacked a neuro interventional infrastructure. As the optimal timing of surgically treating high-grade aneurysmal subarachnoidal hemorrhage is still controversial and our patient presented with hydrocephalus and a Hunt and Hess Grade 4 subarachnoidal hemorrhage, The surgeons first decided to treat the hydrocephalus with the placement of an external ventricular drainage.

The anatomical location of the aneurysm in the narrow space of interpeduncular fossa filled with blood clots and the severe brain edema were additional factors to the poor initial clinical presentation of the patient that made us decide for a delayed surgical treatment. Under intensive care therapy and treatment of the hydrocephalus with the external ventricular drainage, the clinical situation of the patient improved to Hunt and Hess Grade 3 preoperatively. Surgeons decided to clip the aneurysm under hypothermia and temporary cardiac arrest as the wide neck of the aneurysm, its large size and the narrow surgical space could not ensure the safe preparation of the aneurysm neck and the surrounding vessels and would also require a prolonged temporary clip application with increased ischemia risk if a technique with temporarily deflating the aneurysmal sac and allowing comfortable surgical maneuvres was not used.

The author conducted a thorough preoperative cardiological evaluation that revealed no contraindication for application of extracorporeal circulation using the heart–lung-machine. The operation took place 14 days after the rupture of the aneurysm. The surgical approach was done via a right-sided pterional craniotomy combined with orbitozygomatic osteotomy. Then, the sylvian fissure was opened; subsequently, the Liliequist membrane was opened through the optico-carotid cistern revealing the aneurysm. Following, a sternotomy and opening of the pericardium was performed by our cardiac surgeons. After intravenous administration of 35 000 IU heparin, an aortic and venous cannula was placed. The patient then was put on extracorporeal circulation with the use of heart–lung-machine and was cooled gradually down to 18°C.

At this point, a circulatory arrest was caused by stopping the heart–lung-machine. Simultaneously, the head of the operating table was elevated to promote emptying the blood from the aneurysm sac. Thanks to these manipulations, an efficient and comfortable microsurgical preparation of the aneurysm and its neck from the surrounding small perforating arteries and the proximal branches of the basilar artery was achieved. Hereafter, a clip was placed uneventfully occluding the aneurysm. The author gradually rewarmed the patient up to 36.5°C in the following 15 minutes. After the administration of protamine sulfate to antagonize the previously administered heparin, the surgery proceeded with the closure of the craniotomy and the thoracotomy. No postoperative complications were recorded and the patient was able to exit the intensive care unit in 8 weeks. A postoperative DSA confirmed the complete occlusion of the aneurysm (Fig. 2B). The patient was transferred 18 weeks after the operation with no focal neurological deficits at the referring hospital.