g) Statistics concerning the surgical mortality and morbidity are rarely discussed in detail. Generally, the operative mortality in the collected literature is 11.0% (among this number are large – giant AVMs, deep seated AVMs, patients in condition IV-V, some with large hematomas). The statement that the mortality is 5–6% in good risk cases and 20–30% in poor risk cases is helpful but not sufficient to obtain a proper indication as to individual operability.
Useful information has been provided in the series of 81 patients of Haerer (1982) (Tables 1.6 and 1.7).
h) The simultaneous development of three new techniques, microsurgery, embolization and radiation, over the past 20 years has provided, to some extent, healthy competition, yet it has also been exasperating. The success of stereotactic gamma-radiation in the treatment of small to moderate sized AVMs (up to 3 cm in diameter) was and is a factor which reduces just that number of surgically suitable cases for the teaching of young neurosurgeons. In cases of large to giant AVMs, selective embolization and proton beam application are attempts at treatment in otherwise hopeless situations. The results have not as yet been convincing.
The information gained from CT, MRI and selective angiography concerning size, site, shape, precise construction and composition of an AVM, and the studies with Doppler sonography, PET etc. (see Chapter 4: Hemodynamics) still does not allow us to make any prognostic conclusion about the behavior of the AVM with regard to hemorrhage, ischemia, and growth. Statistical studies showing that AVMs are more benign lesions than aneurysms (Crawford et al. 1986) are unsatisfactory. For a given single patient, nobody can readily predict what is going to happen. The exact risk that these lesions present is far from clear (Symon 1976). It remains a ‘perplexing disease’ (Fults and Kelly 1984).
Over the past 30 years the number of publications on cerebral AVM and the number of operated cases have increased enormously:
Anderson and Korbin 1958, Höök and Johanson 1958, Tönnis et al. 1958 (134 cases), Guillaume et al. 1959, Paillas et al. 1959 (70 cases), (80 cases), Poppen 1960, Krenchel 1961 (98 cases), Margolis et al. 1961, Dott and MacCabe 1963, Frugoni and Ruberti 1963 (54 cases), Houdart and Le Besnerais 1963 (44 cases, 3), Sano 1964, Kunc 1965, 1974, 1975, 1977, Pool and Potts 1965 (523 collected cases), Sharkey 1965, Svien and McRae 1965 (95 cases), Perret and Nishioka 1966 (545 collected cases), Pool 1965, 1968, Schatz and Botterell 1966, Walter and Bischof 1966 (72 cases), Henderson and Gomez 1967, Houdart 1967, Carrea and Girado 1968, Castaigne et al. 1968 (53 cases), Kempe 1968, Kunicki 1968, Pertuiset 1968, Verbiest 1968, Weir et al. 1968, French and Chou 1969, Salibi 1969, Vianello 1969, Bartal and Yahel 1970 (43 cases, 37 operated), Maspes and Marini 1970, Milhorat 1970, Müller et al. 1970 (99 cases), Troupp et al. 1970, 1977 (137 cases), Montaut et al. 1971, Perria et al. 1971, Raskind 1971, Amacher et al. 1972 (55 cases), Bushe et al. 1972 (42 cases, 10 operated), Forster et al. 1972 (150 cases between 1930–1960), Green and Vaughan 1972, Krayenbühl and Yaşargil 1972 (523 cases, 303 operated; 187 extirpated), Pia 1972, Amacher and Shillito 1973, French and Seljeskog 1973, Morello and Borghi 1973 (154 cases, 102 operated), Peserino and Frugoni 1973 (91 cases), Waltimo 1973 (43 cases), Boldrey and Pevehouse 1975, Bushe et al. 1975 (56 cases, 46 operated), Chou et al. 1975, Pia 1975 (124 cases), Sano et al. 1975 (205 cases, 165 operated), Pertuiset et al. 1976, Towfighi et al. 1976, Yaşargil et al. 1976, French 1977, Luessenhop and Gennarelli 1977 (300 cases, 49 operated), Filatov et al. 1978 (588 diagnosed, 276 operated, 160 radical removal, 60 endovascular occlusion, 56 palliative procedures), Juhasz 1978, Kosary et al. 1978 (12 cases), Mingrino 1978 (196 cases, 98 operated), Patterson and Voorhies 1978 (50 cases), So 1978, Vigouroux et al. 1978, Andreussi et al. 1979, Dobbelaere et al. (Laine) 1979 (370 cases), Drake 1979 (166 cases, 140 radically operated), Pellettieri et al. (Norlen) 1979 (166 cases, 119 operated), Pertuiset et al. 1979 (162 cases), Sundt 1979 (38 cerebral cases, I†), Wilson et al. 1979 (183 cases, 65 radically operated), Da Pian et al. 1980, Guidetti and Delitala 1980 (145 cases, 95 operated, 92 radically, 50 conservatively), Laine et al. 1980, 1981 (500 cases), Parkinson and Bachers 1980 (100 cases, 90 operated, 10†), Viale et al. 1980, Gerosa et al. 1981, Pertuiset et al. 1981, Aimard 1982 (100 cases), Albert 1982 (178 cases, 140 operated), Debrun et al. 1982 (46 cases, acrylate), Heros 1982, Malis 1982, Martin and Wilson 1982 (116 cases, 16 occl. operated), Patterson 1982, Smith et al. 1982, Suzuki 1982, Graf et al. 1983 (191 cases between 1976–80), Hassler et al. 1983 (35 cases), Ojemann and Crowell 1983, Yonekawa et al. 1983, Black and Farhat 1984, Fujita and Matsumoto 1984, Fults and Kelly 1984 (131 cases, 48 operated between 1979–82), Grisoli et al. 1984, Martin et al. 1984, Rutka and Tucker 1984, Wilson and Stein 1984 (180 cases, 175 radically, 5 subtotally operated, 2†), Adelt et al. 1985 (43 cases), Aoki and Mizutani 1985, Bonnal 1985, Davis and Symon 1985 (129 cases, 69 operated between 1948–1980, 1†), Jomin et al. 1985 (128 cases), Salcman et al. 1985, Samson and Batjer 1985, 1985, Waga et al. 1985, Crawford et al. 1986, Drake 1986.
Monographs
Comprehensive monographs including history, embryology, anatomy, pathological and clinical considerations, analyses of results in operated and nonoperated patients with intracranial AVMs have been published since 1928 by:
Cushing and Bailey 1928, Dandy 1928, Bergstrand, Olivecrona and Tönnis 1936 (in German), Asenjo and Uiberall 1945 (in Spanish), Olivecrona and Ladenheim 1957 (in English), Ley 1957 (in Spanish), Pool and Potts 1965, Lange-Cosack two separate chapters in Olivecrona and Tönnis: Handbook of Neurosurgery, Vol. IV, 1966, Norlén in Olivecrona and Tönnis: Handbook of Neurosurgery, Vol. IV, 1966, Smith, Haerer and Russel 1982, Ojemann and Crowell 1983, Wilson and Stein 1984, Fein and Flamm 1985.
Summary and Outlook
Five aspects of vascular malformations have always been, and still remain, controversial:
1) Pathogenesis,
2) Nomenclature,
3) Classification,
4) Diagnosis,
5) Treatment.
The first 3 aspects are discussed on pages 49–61.
Diagnosis
A vast increase in the number of angiographic studies performed from 1928 onwards, has given rise to the impression that AVMs of all types have become more frequent in their presentation to the clinician. Once any of these lesions have become symptomatic it is generally felt that it has become a more dangerous lesion to that patient. Whether this is true for all types of vascular malformation is uncertain. There is even an argument as to the frequency of occurrence of the various types of anomaly. Earlier, it was generally considered that venous and cavernous malformations were rare, but McCormick (1985) in his large pathological series found that the opposite was true and that venous malformations were 10 times more common than the arterial or arteriovenous forms. The next most frequent form of malformation was the cavernoma. Improved angiographic techniques (Constans et al. 1968, Wendling et al. 1976, Preissig et al. 1976) and the routine use of CT scanning and radionucleide scanning (Partain et al. 1979, Fierstien et al. 1979) demonstrated the increasingly frequent occurrence of venous malformations. The incidence of cavernous malformations has also apparently increased enormously since the intruduction of the MRI scan. Huang et al. (1984) have further revived the 200 year old dispute regarding nomenclature.
Surgery
In terms of surgical treatment:
a) Decompression (Ray 1941 and others), and extra- or intracranial ligature of carotid arteries are now techniques of the past. Potter’s criticism is valid: “The ligature invited arterial blood from somewhere on the ‘easy term’ of low resistance at the expense of normal