Surgical Anatomy of the Vertebrobasilar Territory and Posterior Circle of Willis

BACKGROUND: In the present era of microscopic and neuroendoscopic procedures; the surgical anatomy of the skull base vessels has gained increased significance. The pattern of the vertebrobasilar arterial complex and the posterior circle of Willis (COW) in Nigerians has not been previously reported despite various variants of these complexes existing in different populations. OBJECTIVE: To review and document the size; distribution and anomalies of the vertebrobasilar territory and posterior COW pattern in a Nigerian set of brains. Methods: The target population for this study was a group of Nigerian adults 18 years and above. Specimens from patients with an ante-mortem or post-mortem evidence of meningitis or atherosclerosis were excluded. The size; distribution and anomalies of the vertebrobasilar artery; its branches; and the posterior COW were defined in 50 brains. RESULTS: The male: female ratio was 1.9:1 and a mean age of 44 years. Statistical analysis showed significant differences between the sizes of posterior inferior cerebellar arteries and anterior inferior cerebellar arteries (Student's t = -30.189; p-value = 0.000). Fifty-six percent of the brains had no anomalies. Thirty anomalies were noted in posterior COW compared with six in the vertebrobasilar territory. There were no aneurysms in all the specimens studied. CONCLUSION: Anomalies in the region of the posterior COW are commoner than the vertebrobasilar territory and the region of the posterior communicating artery is the most common site of anomalies in the posterior COW territory. These variations should be taken into account during skull base and carotid surgeries; and cerebral angiography

Neurocritical Care Audit in a Tertiary Institution

Background:The `open' intensive care unit (ICU) predominates in most low and middle economy societies. This is associated with paucity of personnel and cost challenges involved for its maintenance and smooth unning despite the great public demand for this service. Data on neurocritical care in scare in Nigeria and the subregion as a whole. Our objective is to audit our neurocritical care facility; human resources; patient admission and outcome. Patients and Method: We conducted a retrospective audit of all patients admitted to our `open' ICU following a neurological indication. This study was carried out over a one year period (January 2008-December 2008). In addition to patients' boidata; we recorded date of admission; indication for admission; treatment (operative/non-operative); ventilatory support if any; and outcome (Alive or dead). Results: One hundred and twenty-nine patients were admitted during the study period; 85 (65.9) of which was due primarily to a Neurosurgical indication. The overall mortality was 25.9while mortality of ventilated patients was 64.5Mortality rate was significantly by ventilation.Conclusion: Neurological patients account for most of our ICU admission. Hospitals with ICUs should ensure that they have a proper high dependency unit. We also ecommend that appropriate equipments and staff training in the area of neurocritical care be incorporated into existing `open' ICUs in our environment. The use of protocol for ventilated patients and managing common ICU cases and common procedures should enhance treatment outcomes

Congenital Hydrocephalus in Mono and Dizygotic Twins

Background: Information regarding the occurrence of hydrocephalus (HC) in twins is important in establishing the significance of environmental factors as well as a genetic basis in congenital HC aetiology. This was the basis for this study. Methods: A single institution retrospective study was conducted between August 1; 2006 and July 31; 2008. Only those cases of hydrocephalus (based on clinical and radiological testscranial Computeried tomographic or Magnetic resonance imaging scan) that required placement of a ventricular shunt or endoscopic third ventriculostomy were included in the study. Data regarding the patient's demographics; clinical history; examination and the maternal demographics were retrieved and analysed. DNA analysis was done to confirm the fraternity of the twins when applicable. Results: Fifty-eight patients with congenital hydrocephalus presented to the unit over the study period. We identified three sets of twins in the study. Only one set were identical (both male) and both had hydrocephalus. In the remaining two sets only one out of each pair had hydrocephalus (one male and one female). Two of the patients (1male; 1female) were twins with discordant HC. All the children had normal thumbs. DNA analysis confirmed identical twins in both the like sex twins. The mothers were not known diabetics; hypertensive or sickle cell patients neither did they smoke or take alcohol. There was no family history of hydrocephalus in all patients. Conclusion: Concordance for HC is likely if the twins are like sex and identical. Congenital hydrocephalus seems to be a multifactorial disorder; triggered by environmental factors in genetically predisposed individuals

Anomalies, aneurysm and histology of the middle cerebral artery in Nigerian Africans

The histology of the middle cerebral artery (MCA) in Nigerian Africans has not been previously studied. One hundred MCAs obtained at autopsy from fifty adult Nigerians were studied. The vessels were processed and stained with Ehrlich's haematoxylin and eosin, elastic Van Gieson and Masson's trichrome stains. Early branches were given off before the perforators in two middle cerebral arteries, and there was one accessory MCA, making an incidence of anomalies of 3 percent. No aneurysm was observed in any of the cases. The internal elastic laminas were well developed but the external elastic laminas of the vessels were poorly developed. Close to the bifurcations the tunica media tapered gradually and at the bifurcations, the tunica media was completely deficient being replaced by the tunica adventitia (Forbus raphé). The tunica adventitia was thicker at the bifurcations (0.21mm) compared to other sites of the vessel. The average thickness of the MCA tunica media at its origin was 0.12mm while that of the tunica adventitia was O.lOmm. These results are similar to what has been described in the literature for Caucasians. It buttresses the assertion that anatomical anomalies of the MCA are rare. The seemingly low frequency of MCA aneurysms in Nigerian Africans is not due to its anomalies or histology.

La histología de la arteria cerebral media (ACM) de los africanos de Nigeria no ha sido previamente estudiada. Fueron examinadas 100 ACM, obtenidas en autopsias de 50 individuos nigerianos adultos. Las arterias fueron procesadas y teñidas con hematoxilina y eosina de Ehrlich, Van Gieson para fibras elásticas y tricrómico de Masson. Ramas proximales se originan antes de la división en dos arterias cerebrales medias, y había una ACM accesoria, constituyendo una incidencia de anomalías del 3 por ciento. No se observó aneurisma en ninguno de los casos. La lámina elástica interna estaba bien desarrollada, pero la lámina elástica externa de los vasos estaba pobremente desarrollada. Cerca de la bifurcación la túnica media es gradualmente cónica, la túnica media es totalmente deficiente siendo sustituida por la túnica adventicia (Forbus raphé). La túnica adventicia es más gruesa en las bifurcaciones (0.21mm) en comparación con otros lugares del buque. El grosor medio de la túnica media de ACM en su origen fue 0.12mm mientras que el de la túnica adventicia de O.lOmm. Estos resultados son similares a los que han sido descritos en la literatura para Caucásicos. Es importante la afirmación que las anomalías anatómicas de la ACM son raras. La aparentemente baja frecuencia de los aneurismas de ACM en nigerianos africanos no es debido a sus anomalías o a la histología.

Lessons from History: Human Anatomy, from the Origin to the Renaissance / Lecciones de Historia: Anatomía Humana, desde el Origen hasta el Renacimiento

The well-known fact that history writers always seem wiser than the subjects on whom they write is the most logical inherent proof that history is rich in lessons. The history of Anatomy is not an exception. It is full of imperative lessons in the Art and Science of the discipline of Anatomy, which following generations ought to learn. We present a defined brief survey with this in mind.

El hecho bien conocido que los historiadores siempre parecen ser más sensatos que los sujetos sobre quienes escriben, es la más lógica prueba que la historia es rica en lecciones. La historia de la Anatomía no es la excepción. Ella está llena de lecciones imperativas en el arte y ciencia, de la cual generaciones venideras deberían aprender. Presentamos un breve reconocimiento sobre lecciones de la Historia de la Anatomía.

Intrascrotal anomalies related to testicular torsion in nigerians: an anatomical study

Objective: The abnormalities that predispose to torsion are often bilateral. They include horizontally lying testis; bell-clapper deformity (BCD); long mesorchium; well-developed spiral cremasteric muscle and ectopic testis. The pattern and incidence of intrascrotal anomalies that predispose to testicular anomalies in Nigerians have not been studied. Our objective was to define and document this. Material and Methods: The scrotal sacs of fifty cadaver scrotums and inguinal canals from patients aged between 35 and 57 years (mean age: 42 years) were examined. The parameters studied were the location (scrotal or canalicular); alignment (horizontal; vertical); mesorchium (height and width); cremasteric muscle development (well or poorly developed) and parietal tunica vaginalis investment of the testis (normal; intermediate or BCD). Results: Forty-nine testes had descended to the scrotal position; all were anchored by the ligamentum testis. The canalicular position was noted to be present in one cadaver. Forty-eight testes lay vertically. 16of the testes had BCD; while intermediate tunica investment was noted in 12. The most common type of epididymal and testicular relationship was Type I (84). The mesorchium was normal in all specimens examined. Conclusion: The most common anomaly in our study was that of tunica investment; and this is usually bilateral. The need for bilateral orchiopexy in cases of testicular torsion is further strengthened since the anatomic anomalies are usually bilateral