SUMMARY

A review of 139 histologically verified intraspinal tumours in Black Eastern Africans who were operated upon in Nairobi. Kenya in the last 25 years, is presented. Intraspinal tumours in this series are compared with other studies from Africa and elsewhere. Extradural and intramedullary tumours together with cervical spine tumours appear to be more frequent in this series. There is a high incidence ofdumbell tumours in the neurinomas. Sarcomas are the most common type of tumours and mainly affect he thoracic spine

Keywords : Africa , Spinal cord, Spine, Tumours

RESUME

139 cas de tumeurs intrarachidiennes observées chez des noirs de 1’Afrique de l’Est à Nairobi (Kenya), ont été opérées durant 25 ans, et confirmées histologiquement, Les tumeurs intrarachidiennes sont comparées à celles d’autres études publiées en Afrique et dans d’autres pays. Les tumeurs à la fois extradurales et intramédullaires et les tumeurs du rachis cervical sont plus fréquentes dans cette série. Il existe une incidence élevée de tumeurs en forme d’haltère parmi les neurinomes. Les sarcomes sont les tumeurs les plus fréquentes et affectent surtout le rachis dorsal.

Mots cles : Afrique, Tumeurs intra-rachidiennes, Compression médullaire, Rachis

A series of 139 Black Eastern African patients have been treated surgically for intraspinal tumours (I.S.T.) in the last 25 years, in Nairobi, Kenya. This series does not include vascular malformation, parasitic or infectious lesions nor arachnoditis. The ratio between intracranial tumours (605 cases) and I.S.T. (139 cases) in this series is 4.35: 1, with a higher incidence of intraspinal tumours when compared with other larger series, as ofBROAGER, 1953 (10.1) or MALECI, 1954 (8:1). The higher incidence of intraspinal tumours in our series may be due to a higher mortality rate of intracranial tumours before any treatment. (RUBERTI et al. 1976) The relative incidence of various histopathological types of these tumours compared in percentage with other African and Western series was as follows:

Table 1 : Site of Intraspinal Tumours (in percentage)

Our series compares similarly to the one of SOROUR et al, Egypt 1970, and to the overseases series in regard of site ofI.S.T. In the series ofODEKU et al, Nigeria 1976, and GARRIDO et all Zimbabwe 1985, there is a higher percentage ofextradural tumours (ODEKU et al 80.3%, GARRIDO et al 62.3% ) and consequent relative lower incidence of intradural tumours, although the main causes were the same i.e meningiomas and neurinomas. The incidence of intramedullary tumours coincides more or less with all other series.

There is a high incidence ofI.S.T. betweeen the age of 11- 50 years (about a equal distribution in the 2nd, 3rd and 4th decade of life) instead of being between 35-55 years of age as in the large overseas series.

In the gliomas series, the astrocytoma is the most common histopathology found, (18 cases, 82%), with only a few ependymonas (4 cases or 18%). The metastatic tumours are all hystopathologically carcinomas: 2 bronchial, 2 prostate, 1 breast, 1 thyroid, the rest undentified carcinomas. Out of 10 metastasis 9 are located in the thoracic and one in the lumbar region.
The age incidence oflntraspinal tumour in this series is shown in table 2:

Table 2 : Age distribution of intraspinal tumours

In our series there was a high incidence of sarcomas and gliomas in the first two decades of life. In the third and forth decades there was a prevalence of neurinomas and meningiomas, followed by gliomas and sarcomas. In the fifth and sixth decades there was a prevalence of meningiomas and nerurinomas followed by sarcomas and metastatic tumours almost in equal number. Over the age of sixth we fiound only two sarcomas and one metastatic tumour.
There has been a tendency to malignancy (gliomas and sarcomas) in the young age group compared with the middle and old age group were benign (menigiomas and neurinomas) are prevalent.

The sex incidence of I.S.T. in this series as shown in Table 3:

Table 3 : Sex incidence of intraspinal tumours

There is a prevalence of males over females with a ratiomale – female of 1.4:1, Males are 81 cases, 58.2 per cent, females are 58 cases, 41.8 percent, but the difference is not as marked as per mtracranial tumours. It seems that malignant tumours (gliomas, sarcomas and metastatic tumours) affects the male more than the female, while beningn tumours are preferential in the female The preferential site of I.S.T. in the Eastern African patients was as follows:

Table 4 : Preferenctial spinal location of I.S.T.

There is a prevalence of benign tumours in the cervical spine with a high incidence of neurinomas and meningiomas; also the gliomas are frequent at this level The thoracic spine is affected more by sarcomas, with a. lower incidence of benign tumours, hi the lumbar spine there is again a prevalence of benign tumours, 11 between neurinomas and lipomas against 5 sarcomas and metastases.
Two interesting points emerge from these series: the relatively higher incidence of the cervical tumours compared with those of the thoracic tract (in larger series the incidence is largely in favour of tumours of the thoracic tract), and the contrast between the liigh incidence of benign tumours of the cervical spine compared with the high incidence of malignant tumours of the thoracic tract.

DISCUSSION

Tlie incidence ofintraspmal tumours compared with intracranial tumours in higher this series than in larger over seases series Tlie age distribution of I.S.T. is almost equal in the various decades of life from the age of ten to the age of fifty, instead of being 35 and .55 years of age as in other large series: this may be certainly due to tlie large, young population in this part of the world This study correlates with various others in sex incidence and suggest that I.S.T are prevalent in males than in female
The younger age group appear to be affected more by malignant tumours (sarcomas and gliomas) while the middle and older age group seem to be affected more by benign tumours (neurinomas and meningiomas) Intraspinal tumours appear to affect males more than females. Malignant tumours (gliomas, sarcoma, and metastases are more frequent in the males, whilst benign tumours have a higher incidence in the females (meningiomas and neurinomas)
Extradural, intramedullary tumours as well as the cervical spine tumours have a higher incidence in this series. The cervical and lumbar spine are mainly site of benign tumours, while in the thoracic spine there is a high incidence of malignancies . A high percentage. (50 percent ) of dumbell tumours have been found in the neurinomas.
The use of an operating microscope has proven to be very useful in reducing the trauma due to the removal the spinal cord tumours, particularly for the removal of intramedullary gliomas