Introduction

Subarachnoid haemorrhage (SAH) and intracranial aneurysms have been a condition of humans for thousands of years. An Egyptian skull dating back to the fifth or sixth century AD contained erosive bony lesions referable to a probable aneurysm of the internal carotid artery (Sundt 1990). Annotations to cerebral aneurysms can be found in Egyptian, Greek, and Arabic literary antiquities (de Moulin 1961; Al-Rodhan 1986).

The modern history of the study and treatment of SAH and intracranial aneurysms parallels the history of development of neurosurgery. From the anatomists of the 1700s, to the first successful ligation by Cooper in 1808 (Schorstein 1940), to Horsley's confirmation of an intracranial aneurysm at craniotomy (Beadles 1907), to the introduction of angiography by Moniz in 1927 (Moniz et al. 1928), to Dott's wrapping of an intracranial aneurysm in 1931 (Dott 1969), and to Dandy's clipping of an intracranial internal carotid artery aneurysm (Cushing 1911; Dandy 1938), the advances in neurosurgery have often been designed better to treat patients suffering from SAH. Perhaps the greatest advance in the treatment of aneurysms was the introduction of the operating microscope and microsurgical techniques in the 1960s. Despite these great technical advances, the treatment of cerebral aneurysms and subarachnoid hemorrhage remains a formidable challenge. The purpose of this chapter is to examine SAH in terms of its incidence, aetiology, clinical features, natural history and surgical outcomes.

The incidence of intracranial aneurysms is estimated at 1–8% of the general population according to autopsy and angiographic series (McCormick & Nofzinger 1965; Pakarinen 1967; Stehbens 1972; Sekhar & Hevos 1981; Atkinson et al. 1989)