SUMMARY

This is a prospective study of 146 black African patients with intracranial aneurisms seen by the Author in 30 years of practice in Kenya. Out of 146 patients, 131 have been surgically treated mainly (90%) by clipping the aneurismal neck. The majority of the patients were Kenyans but others were from Eastern African Region. An analysis of the intracranial aneurismatic disease is carried out, with particular reference to the neuroepidemiology of this condition as seen in the African patients and to the pathological, diagnostic and prognostic aspects as related to the management.

RESUME

146 patients Africains noirs presentant un aneurisme intracranien, qui ont ete vus par l’Auteur en 30 ans de pratique medicale au Kenya, font l’objet d’une etude prospective. 131 de ces 146 patients ont ete traites chirurgicalement, la plupart (90%) par clippage au collet de l’aneurisme. La majorite de ces patients etaient Kenyans, les autres originaires de l’Afrique de l’Est. Une analyse de la maladie aneurysmale intracranienne est entreprise a partir, en particulier, des donnees qui ressortent de la neuroepidemiologie de cette maladie chez les patients Africains et des aspects pathologiques, diagnostiques et pronostiques, en relation au traitement chirurgical.

Keywords : Aneurisms, Intracranial East Africa

A series of 146 black African patients with intracranial aneurisms has been seen by the Author in Nairobi, Kenya, in the course of 30 years. The majority of patients were Kenyans but others were coming from the East African region.

The incidence of intracranial aneurysms (I.A.) in East Africa is unknown as unknown is the incident cerebro-vascular disease and cardio-vascular diseases. We are perhaps better informed about the relative incidence or cerebro-vascular disease and intracranial aneurisms in the African when compared with the other neurological pathology observed in the same circumstance by the same Author. In the present series cerebro-vascular diseases represent 6-8% of the approximately 10,000 African patients seen by the Author in 30 years time, and this incidence is similar to other large overseas series. The vascular malformation are approximately a quarter of the cerebro-vascular diseases and of them the 75% are intracranial aneurisms and 25% arterio-venous malformations.

There is a lower incidence of I.A. when compared with the arterio-venous malformations in the African: the I.A. versus AVM stands at 3:1 in the African, whilst in the western series it is 10; 1. This can be partly explained with the fact that the AVM manifests clinically early in life whilst the I.A. are clinically more frequent at the age between 40 and 60 years, that the African have a shorter span of life, that the haemorrhages due to the AVM are less catastrophic and gives more often focal signs that the subarachnoidal hemorrhages due to an aneurism that can be confused, at the general practitioner level, with a meningitis, cerebral malaria and other diseases.

The age incidence for the intracranial aneurisms in this series was as follows:

TABLE I – AGE INCIDENCE-INTRACRANIAL-ANEURISMS-AFRICAN

Although intracranial aneurisms are encountered at all ages, they reach the peak between 40 and 60 years in all series; in this series it has to be noted that almost 50 per cent (46.5%) of cases are in the first four decades of life and this could be explained with the tact that 50 percent of the population in East Africa is below the age of 15 years.

The sex incidence was 89 men and 57 women with a ratio of 1.56 to 1. Unruptured aneurisms are more common in women whilst with regards to ruptured aneurysms, under the age of 40 years men preponderate, over the age of 50 women proponderated to a steadily increasing degree. Aneurysms of the internal carotid artery are more common in women, whereas those arising from the anterior-cerebral and anterior communicating artery are more frequent in men.

In the first two decades of life there were no aneurysms of the anterior cerebral and anterior communicating arteries. The incidence of aneurysm of the internal carotid artery are the same in the age between 20 and 40 years, the ones of the ACA and A. Com. A. are twice as frequent in the age between 40 to 60 than between 20-40.

The site of the aneurisms was as following.

TABLE 2 – LOCATION INTRACRANIAL ANEURISMS-AFRICAN

As in other larger series the aneurisms of the internal carotid artery are the most frequent (45%) followed by the aneurisms of the anterior cerebral-anterior communicating artery (34%) and by the aneurisms of the middle cerebral artery (16.5%).

The number of intracranial bleedings for each aneurisms was as shown in table 3.

TABLE 3 – NUMBER OF INTRACRANIAL BLEEDINGS FOR EACH ANEURISM

Unruptured aneurysms in this series are 11 cases. Of the remaining 135 cases, 96 had one episode of intracranial bleeding, 21 cases 2 episodes 8 cases 3 episodes and 10 cases more than three episodes. 51 cases were on the right side, 46 on the left, the other were on the midline. In this series the recurrence of bleeding is far more common for the internal carotid artery aneurisms, less for the ones of the arterior communicating artery and absent for the ones of the middle cerebral artery. In many other series the anterior communicating aneurism is the most likely to bleed again, stastical confirmation of a general opinion (NORTHFIELD 1973)

The majority of the patients had possibly four vessels angiography and more recently also CT Scan and MRI investigations if required. Multiple aneurysms were found in only two cases: this may be due to the fact that four vessels angiography was not done in all patients. Arterial spasm was found in 56 patients (38 3%) and a conspicuous intracerebral hematoma in 23 cases (15.7 per cent). The intracerebral hematomas were more frequent for the aneurysms of the middle cerebral artery (16 cases69.5%) followed by the aneurysm on the anterior communication artery (five cases-21.7%) whilst they were rare for the intracranial aneurisms of the internal carotid artery and bifurcation (2 cases-8.6%).

For clinical assesment of these cases we have followed the classification of HUNT and HESS (1968). The cases were divided as follows:

TABLE 4 – CLINICAL FEATURES FOLLOWING HUNT AND HESS CLASSIFICATION

As seen in the above table, the condition of these patients were quite satisfactory in 60 percent of them, discrete in 17 per cent and very bad in more than 20 per cent of cases. Out of 146 cases, 131 underwent surgical treatment. Of the non surgical cases, 4 died before planned surgery (one aneurism of basilar artery, one of middle cerebral artery that died one hour before going to theatre, two patients with aneurisms of the anterior Comm. Artery respectively). 11 cases either refused surgery or were transferred elsewhere.

SURGICAL TREATMENT

It is generally agreed that the surgical risk in aneurism surgery is strictly related to the patients condition as well as to other factor as age, location of the aneurysm, hypertension, diabetes, arteriosclerosis, chronic pulmonary disease. Many criteria have been proposed to evaluated risks but we have given the preference again to the classification of HUNT and HESS (1968) that takes in account mainly the intensity of the meningeal reaction, the severity of neurological deficit, the presence or absence of significant associated diseases: this should provide in our experience the best clinical criteria for the estimate of surgical risk.

Out of 131 in this series, the relationship between grade of surgical risk and mortality following the classification of HUNT and HESS was as follows:

TABLE 5 – RELATIONSHIP BETWEEN GRADE OF SURGICAL RISK AND MORTALITY

This table confirms, if there was any need, that one should avoid to perform any surgery in patients grade five and that in patients grade 4 the risk of surgery is extremely high. The policy should be to delay surgery in patients grade 4 and 5 until the conditions are improving to grade 3 or they deteriorate until death occurs. Our policy now is that not even angiographic investigations should be carried out in cases grade five, but only a C.T. Scan of the head should be done to rule out a possible intracerebral hematoma, that may be worth evacuating in certain conditions.

In 118 cases a clip was applied on the aneurysmal neck (90% of cases), in 6 cases the aneurysm was wrapped in muscle (4.5%), in 5 cases a trapping technique was carried out for aneurisms of the internal carotid artery (4.5% of cases) and in one case of intracavernous aneurysms, a ligature of the internal carotid artery in the neck was performed. The Ibllowing table shows the relationship between site of intracranial aneurisms technique used and mortality rate:

TABLE 6 – RELATIONSHIP BETWEEN SITE- TECHNIQUE- MORTALITY

Only two patients have been reoperated: one for correcting the position of the clip that was not properly applied. and one case that developed a hypertensive hydrocephalous in which a shunt was inserted. There has been no mortality in cases where wrapping has been used. Two cases of trapping of the internal carotid artery for aneurism that burst during dissection died, and one case of progressive ligature of the internal carotid artery with the MAYFIELD clamp .for an intracavenous aneurism survived without neurological deficit. The use of clipping the aneurysmal neck involved a 25 per cent of mortality. ‘The relationship between the time of last heamorrhage, surgery and mortality is shown in table 7.

TABLE 7 – RELATIONSHIP BETWEEN LAST HEMORRHAGE-SURGERY-MORTALITY

The above table shows the timing of surgery from last heamorrhage and relationship with mortality: earlier the surgery, higher the mortality: nevertheless it has to be considered that the range of mortality is mainly dependent not so much on the timing of surgery related to the last heamorrhage but by the clinical state ot the patient at the time of the operation, status reflecting the degree of brain damage and accompanying complications. In this series, if the patients were practically symptom free, the mortality was 3.7 per cent, when in grade five of HUNT and HESS scale, the mortality was 100 per cent. In intermediate groups the mortality rates varies accordingly as already emphasised: the level of conciousness was the most valuable index for predicting the outcome.

RESULTS

The study of the literature discloses an operative mortality for the inracranial surgical treatment of intracranial aneurism ranging from 5 to 50 per cent. The Co-operative study (VIII part 2) provided 979 patients treated in this way and 31 per cent died: aneurisms of the middle cerebral artery had a mortality rate of 22 percent, on the internal carotid artery 36 per cent and on the anterior communicating artery 30 per cent. In the Author’s personal series of 130 patients undergoing intracranial direct obliteration, reinforcement or trapping, the mortality has been of 36 cases (27.7 per cent). The distribution in the three major groups was: internal carotid artery 11 died (18 percent): anterior communicating artery 14 died (36 per cent): middle cerebral artery 10 died (47 per cent).

The operation was carried out after the heamorrhage when the patient’s conditions appeared to allow it. Mild hypotension with temporary occlusion of the carotid in the neck in large aneurisms, has been used, associated with lumbar CSF drainage for better exposure, magnification with loops or microscope.

Of the 95 survivors, 11 did not report for a check up after having been discharged in good conditions. 84 of them had a follow up from 2 months to 12 years with an average follow up of up to one and a half years. The results were as follows:

TABLE 8 – RESULTS OF SURGERY FOR VARIOUS TYPES OF ANEURISMS

The above table shows that 89 per cent of these patients have full working capacity with 26 per cent with minimal disability (like some loss of concentration, minimal weakness in one limb etc).

The other 9 patients ( 11 per cent) are not working because disabled but able to care for themselves and are relatively independent. No patient is bed ridden or in a nursing home.

The surgery of berry intracranial aneurism, despite the progress in techniques and surgical ingenuity still carries a high mortality due to the severity of the heamorrhage causing often intracerebral hematomas, arterial spasm and other complications eventually affecting badly the surrounding brain and the brain stem.