Microsurgical Anatomy of the Labyrinthine Artery and Clinical Relevance.

AIM: To describe the origin, the course, and relationships of the labyrinthine artery (LA). MATERIAL AND METHODS: Thanks to a colored silicone mix preparation, ten cranial bases were examined using x3 to x40 magnification under surgical microscope. RESULTS: The LA often arose from the meatal loop of the anterior inferior cerebellar artery (AICA) (90%), or basilar artery (10%). The loop was extra-meatal of the internal auditory meatus (IAM) in 30%, at the opening of the internal auditory meatus in 20%, or intra-meatal in 35%. The AICA coursed in closed relationship to the VII and VIII cranial nerves. It coursed between VII and VIII cranial nerve roots in 85%, or passed over the ventral side of both VII and VIII cranial nerve. The average diameter of the LA was 0.2 +/- 0.05 mm. LA was single trunk in 60%, and bi-arterial in 40%. CONCLUSION: The implication of these anatomic findings for cerebello-pontine angle tumors surgery and neurovascular pathology such as infarction, aneurysm of the LA or the AICA are reviewed and discussed.

Functional consequences of a section of the anterior part of the body of the corpus callosum: evidence from an interhemispheric transcallosal approach.

The aim of this study was to determine the neuropsychological consequences of a middle interhemispheric approach for the removal of tumors of the third or lateral ventricles. A retrospective analysis of eight callosotomized patients for ventricular tumors (three males/five females; mean age: 48.7 ± 11.2 years; education level: 11.9 ± 2.9 years) and eight healthy subjects was performed. An extensive neuropsychological test battery was used to evaluate global intellectual efficiency, memory capacities, executive functions, and interhemispheric transfer of a procedural learning task (serial reaction time task/SRTT). Neuropsychological results showed that: (1) five of eight patients operated through a middle transcallosal approach had disturbances of verbal or visual memory; (2) three of eight patients displayed a dysexecutive cognitive syndrome(two of eight of whom presenting with a deficit of verbal fluency); (3) two of eight patients presented a dysexecutive behavior syndrome; and (4) with regard to the SRTT, although all participants learned the task, in contrast to controls, the callosotomized patients showed an increase in reaction times and an absence of interhemispheric transfer of learning from one hand to the other. The transcallosal approach transects a large number of callosal fibers. This damage accounts for the deficits of memory, the dysexecutive cognitive and behavioral syndrome, and disturbances in interhemispheric transfer of learning.

A phase-contrast MRI study of acute and chronic hydrodynamic alterations after hydrocephalus induced by subarachnoid hemorrhage.

OBJECTIVE: To determine acute intracranial hydrodynamic changes after subarachnoid hemorrhage (SAH) via phase-contrast MRI (PC-MRI) analysis of the CSF stroke volume in the aqueduct (SVaq) and the foramen magnum (SVfm). METHODS: A prospective PC-MRI study was performed on 34 SAH patients in the acute and late phase. Data on CSF flow and hemorrhage site were analyzed according to acute or chronic hydrocephalus (HC). RESULTS: In the acute phase, CSF analysis was performed for 31 patients, 12 of whom presented HC. All 12 had an abnormal SVaq; those with communicating HC (n = 7) had an elevated SV and those with noncommunicating HC (n = 5) had a nil SV. None of the patients with a normal SVaq (n = 11) developed acute HC. Intraventricular bleeding led to more cases of acute HC (P = .005), which was communicating in 58% of cases. In the chronic phase, CSF analysis was performed for 27 patients, 7 of whom presented HC. None of these 7 patients displayed a depressed SVaq. CONCLUSION: SAH led to changes in cerebrospinal fluid hydrodynamics in the majority of patients. Acute HC was communicating in most cases, even when there was intraventricular bleeding. In the late phase, all chronic HC were communicating and did not display aqueductal stenosis.

The duodenal fossae: anatomic study and clinical correlations.

The aim of this study was to present anatomic macroscopic aspects and the relationship between the duodenum and the posterior abdominal wall. The authors describe anatomic types of peritoneal duodenal fossae and stress some points of surgical importance. Twenty-four cadavers, fixed in formalin, were dissected. Ten peritoneal fossae were given prominence and the authors show the anatomical structures topographically, from a superficial plane to a deep viscerae level. There is usually a complete fusion of the duodenal loop with the posterior parietal peritoneum except the duodenojejunal flexure. The study reveals three right retroduodenal fossae, three left retroduodenal fossae, two inferior duodenal fossae, one left paraduodenal fossa and one superior duodenal fossa. These peritoneal recesses mostly result from an incomplete adhesion of the Treitz's fascia. This work provides some explanation of paraduodenal hernias that represent a rare case of intestinal obstruction. Two cases of these internal hernias are illustrated and their pathophysiology and embryologic basis are discussed.