Ruptured Cerebral Aneurysm of the Anterior Circulation

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1 Original Articles * Division of Neurosurgery Department of Surgery Ruptured Cerebral Aneurysm of the Anterior Circulation Management and Microsurgical Treatment Ossama Al-Mefty, MD* ABSTRACT Based on the author's experience with the last 20 consecutive cases of anterior circulation aneurysm and on a review of the literature, this paper emphasizes to the medical community in Saudi Arabia that advances in microsurgical techniques employed in aneurysm surgery have greatly reduced the high mortality previously associated with such surgery. Aneurysms that have been considered inoperable are now accessible. It is hoped that as physicians in the area become more aware of these techniques in treating ruptured cerebral aneurysm, more patients in Saudi Arabia will benefit from the immediate diagnosis and appropriate management. O Al-Mefty, Ruptured Cerebral Aneurysm of the Anterior Circulation. 1983; 3(2): KEYWORDS: Cerebral aneurysm, Microsurgery, Subarachnoid hemorrhage Introduction Ruptured intracranial aneurysm is a surgically curable disease. It is seen with significant frequency in Western countries. During the past 6 years, only 15 patients were treated for ruptured cerebral aneurysms at King Faisal Specialist Hospital and Research Centre. 1 The cause of this low incidence is difficult to determine. It could be related to a truly low incidence of cerebral aneurysm in the Saudi Arabian population or to a high incidence of misdiagnosis. This paper is addressed to all the health personnel in the area to help increase the awareness of ruptured cerebral aneurysm diagnosis and proper management. Preoperative Management Initial Management A complaint of sudden severe headache should always raise the probability of subarachnoid hemorrhage. Many times such a complaint has been dismissed only for the patient to return in a few days or weeks with recurrent, fatal bleeding. A thorough clinical evaluation plays a vital role in deciding the preoperative management, the operative timing, and the final outcome. Patients' conditions are classsified according to the modified Botterell grading system as follows: 2 Grade I Grade II Minimal bleed, alert, no neurological deficit. Mild bleed, alert, minimal neurological deficit as a third nerve palsy, stiff neck. Grade III Moderate bleed, drowsy or confused, stiff neck, with or without neurological deficit. Grade IV Moderate or severe bleed, semicoma, with or without neurological deficit. Grade V Severe bleed, coma, and decerebrate movements. Patients over age 50 are placed in the next highest grade. They are also classified in a higher grade if they have a major heart, lung, kidney, or liver disorder.

2 The diagnosis of subarachnoid hemorrhage should be confirmed as soon as possible by means of a computerized tomography (CT) scan, which frequently demonstrates the blood in the subarachnoid space (Figure 1). A CT scan also may show associated hydrocephalus or hematoma and may help in localizing the rupturing aneurysm in the case of multiple aneurysms (Figure 2). Finally, CT scanning might have value in determining the prognosis. Figure 1. CT scan in patient with ruptured middle cerebral artery aneurysm (arrow indicates blood within the sylvian fissure). Figure 2. CT scan in patient with hydrocephalus following ruptured aneurysm. Lumbar puncture (where there is no evidence of mass lesion) is still a time-honored, valuable, inexpensive, and definitive way of diagnosing sub-arachnoid hemorrhage. Xanthochromia in the supernatant fluid confirms the diagnosis of subarachnoid hemorrhage and -differentiates it from "traumatic" spinal tap. Sedation, control of blood pressure, control of seizures, and antifibrinolytic agents such as epsilon aminocaproic acid (Amicar) are used to minimize the incidence of rebleeding until definitive surgical management is carried out. Angiography Four-vessel cerebral angiography is needed to visualize the cerebral aneurysm and to discover the presence of multiple aneurysms (Figure 3). Subtraction angiographic views, along with occasional stereoscopic views or magnification, will enhance the information obtained. The configuration of the aneurysm, its neck, the surrounding

3 vessels, the parent vessel, and the presence of vasospasm are well delineated by selective angiography, and they are critical factors in the planning of surgical attack. An angiogram usually is obtained postoperatively to confirm the complete clipping of the aneurysm and the patency of the surrounding vessels. Figure 3. Subtraction oblique view demonstrates an anterior communicating artery aneurysm (arrow). Microsurgical Treatment The exact timing of surgical intervention is still in dispute. 3 Generally, the author prefers to wait 10 to 14 days after the aneurysmal hemorrhage to allow the cerebral edema to subside and to avoid surgery during the peak of vasospasm. However, patients clinically in Grades I and II (alert, oriented, and without major neurological deficits) will be considered for earlier surgery, while patients in Grades III and IV (various degrees of altered consciousness and neurological deficits) may be further delayed. Patients with acute hydrocephalus or associated significant intracranial hematoma require immediate, proper surgery after the diagnosis is confirmed by computerized tomography. Using the operative microscope, aneurysms at virtually all locations in the circle of Willis may be approached through frontotemporal craniotomy. The patient is positioned in the headrest; particular attention is given to preserving the superficial temporal artery for extracranial-intracranial microanastomosis, if ever needed in the future 4 (Figure 4). A small, frontotemporal flap is raised and the sphenoid ridge is drilled away to facilitate exposure along the base of the skull, minimizing brain retraction. The sylvian fissure is opened to allow access, without undue retraction, to the circle of Willis in the base of the brain. A sharp, micro-dissecting technique with special microinstruments is used throughout the dissection. The aneurysm is meticulously dissected, along with the surrounding parent vessel and its branches, completely preserving the small but vitally important perforating vessels (Figure 5). The perforating vessels are often so intimately associated with the neck of the aneurysm that it would be virtually impossible to dissect and preserve them without the aid of the microscope. Once the aneurysm has been carefully dissected, a clip may then be secured at its base, thus permanently and effectively isolating it from the circulation and ending the risk of future rupture (Figures 6 and 7). Advances in neuroanesthesiology have permitted the surgeon to work on a slack brain. The use of hyperventilation with the close monitoring of blood gases is standard practice to control intracranial pressure. Spinal fluid drainage is routinely used by the author to facilitate exposure and minimize retraction. One of the most important factors of aneurysm surgery has been the use of the hypotension technique during the crucial moments of the aneurysm dissection and clipping. The importance of an operating team being familiar with and knowledgeable in this particular type of surgery cannot be overemphasized. The continuous television monitor display allows the rest of the operating team and the anesthetist to observe the operation as the surgeon sees it through the operative microscope.

4 Figure 4. Patient positioned in Mayfield headrest. Solid line indicates incision line. Dotted line indicates the course of the superficial temporal artery. Figure 5. Exposure of anterior communicating artery aneurysm. The optic chiasma and both optic nerves are well visualized. The artery of Heubner and small perforating branch also are seen and preserved.

5 Figure 6. Middle cerebral artery aneurysm completely dissected and ready for clipping. Figure 7. Same middle cerebral artery with a clip applied to its neck. Discussion Cerebral aneurysm in Western countries is relatively common. Its prevalence at autopsy is reported to be from 0.5 to 10 percent. However, the prevalence is thought to be lower in the Oriental race than in Caucasians. 5 There is no routine autopsy series to ascertain the prevalence of cerebral aneurysm in Saudi Arabia. Ramamurthi has indicated there is a low incidence of clinically diagnosed aneurysm in India, citing similar impressions from Iran. 6 During the past 6 years only 15 patients were treated for ruptured cerebral aneurysm at King Faisal Specialist Hospital, which is the major neurosurgical referral center in the Kingdom of Saudi Arabia. A patient with a ruptured cerebral aneurysm may die before reaching a hospital. It is also very easy to overlook the diagnosis when the patient presents with the complaint of headache and there are no other findings. Thus, a true incidence of ruptured intracranial aneurysm can be determined only when full knowledge of the disease becomes common. About 70 percent of patients with subarachnoid hemorrhage due to ruptured intracranial aneurysms will survive the first bleeding. The majority of these patients require definitive surgical treatment to protect them from recurrent, fatal bleeding, which often occurs 7 to 10 days after the first hemorrhage This protection will be accomplished

6 by a direct surgical attack and clipping of the aneurysm utilizing microsurgical techniques These techniques permit a smaller craniotomy, minimal brain retraction, excellent delineation of the anatomy, precise clipping of the aneurysm, and preservation of the vitally important neighboring and perforating vessels. Use of these techniques underlies the dramatic reduction in mortality and morbidity, from 33 percent average mortality in the cooperative study of intracranial aneurysms and subarachnoid hemorrhage to about 4 percent or less. 13,14 However, this rate is still related to the patient grading. The author's experience with a series of 20 consecutive patients with anterior circulation aneurysms treated by microsurgical techniques confirms these findings. There was no mortality. One patient had a recurrent subarachnoid hemorrhage 1 month after surgery during which her ophthalmic artery aneurysm was clipped. The recurrent bleeding was due to a small remnant of the aneurysm neck. She had temporary hemiparesis due to postoperative spasm. One patient required a shunt for hydrocephalus. All of the patients have returned to active life. Summary Advances in microsurgery have made ruptured cerebral aneurysm a surgically curable disease. It is hoped that this article will bring to the attention of the medical community in Saudi Arabia the importance of prompt, accurate diagnosis of ruptured aneurysm and the proper preoperative management and microsurgical treatment. 1. Carney P: Personal communication. REFERENCES 2. Lougheed WM, Marshall BM: Management of aneurysms of the anterior circulation by intracranial procedures. In: Youmans JR, ed. Yournans' Neurological Surgery, Philadelphia, WB Saunders Co 1973 pp Kassell NF, Boarini DJ, Adams HP, et al.: Overall management of ruptured aneurysm: comparison of early and late operation. Neurosurg 9(2): Al-Mefty O, Velo AG: Preservation of superficial temporal artery in frontotemporal flaps (letter). Neurosurg 6: Stehbens WE: Pathohgy of the Cerebral Blood Vessels. St Louis, CV Mosby Co 1972 pp Ramamurthi B: Incidence of intracranial aneurysms in India. J Neurosurg 30: Jane JA, Winn HR, Richardson AE: The natural history of intracranial aneurysms: rebleeding rates during the acute and longterm period and implication for surgical management. Clin Neurosurg 24: Rhoton AL, Jackson FE, Gleave J, et al.: Congenital and traumatic intracranial aneurysms. Clin Symp 29(4): Sahs AL, Perret GE, Locksley HN, et al.: Intracranial Aneurysms and Subarachnoid Hemorrhage. A Cooperative Study. Philadelphia, JB Lippincott Co Sundt TM, Whisnant JP: Subarachnoid hemorrhage from intracranial aneurysms: surgical management and natural history of disease. New Engl J Med 299: Fox JL: Microsurgical exposure of intracranial aneurysm. J Microsurg 1: Nornes H, Wikeby P: Results of microsurgical management of intracranial aneurysms. J Neurosurg 51(5): Yasargil MG, Fox JL: The microsurgical approach to intracranial aneurysms. Surg Neurol 3(1): Skultety FM, Nishioka H: Report on the cooperative study of intracranial aneurysms and subarachnoid hemorrhage. Section VIII, part 2. The results of intracranial surgery in the treatment of aneurysm. J Neurosurg 25: