Measurements of the Obersteiner-Redlich zone of the vagus nerve and their possible clinical applications.

The aim of our study was to describe anatomical variability of the root entry zone (REZ), also called the Obersteiner-Redlich zone, that represents the "junction zone" of glia and Schwann sheath of the cranial nerves. This zone has some clinical implications. The pulsatile compression of REZ by a vessel may produce clinical symptoms, such us trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia torticollis spasmodicus or even symptoms of essential hypertension when a vascular cross compression of REZ of a left vagus nerve is present. The vessel--cranial nerve contact in the skull base cysterns may be visualized in radiologic examinations, most accurately in magnetic resonance imaging. Because, we cannot distinguish the REZ from the rest of the vagus nerve in radiologic examinations we decided to measure the length of its REZ. The microanatomical study of the length of REZ zone of the vagus nerve was performed on 21 nerves taken from 17 human brain stems (12 men, 5 women, 14 left, 7 right), fixed with 8% buffered formalin solution. Paraffin embedded tissue was cut into 10-micron-thick sections parallel to the nerve longitudinal axis and stained with hematoxilin & eosin. Each of the nerves showed the presence of a zone of oligodendrocyte myelination, mean length 2 +/- 0.3 mm. In 17 nerves the transitional zone formed a cone-like process, in 4 nerves was shaped irregularly. The length of REZ (oligodendrocyte myelination plus "glial dome") had the mean length 3.5 +/- 0.9 mm.

Evaluation of Gore-Tex graft patency in hemodialysis access.

AIM: The purpose of this retrospective study was to analyze the patency and complications of Gore-Tex grafts used in hemodialysis (HD) access. METHODS: In the last 16 years, 1649 surgical procedures were performed on 655 patients to ensure and maintain permanent HD access. The study group consisted of 64 HD patients on whom 81 vascular synthetic PTFE Gore-tex grafts were performed. There were 28 males and 36 females, 3 of them were children (4.7%). Mean age was 54.2 years (range 15-77). Two types of Gore-Tex prosthesis were used: Diastat and Stretch. All grafts were implanted in the upper extremities. Kaplan-Meier survival curves were calculated to determine primary and secondary patency. Log-rank analysis was used to determine differences between curves. RESULTS: Primary and secondary patency at 12 months was 52.5% and 67.5%, and at 18 months respectively 41.5% and 58.2%. The Diastat graft had a lower primary and secondary patency compared with the Stretch graft (respectively p = 0.02 and p = 0.008). Factors such as gender, coexisting diabetes and hypertension did not determine graft patency. Thrombosis was one of the most frequent complications. The remaining complications included stenosis, pseudoaneurysms, infection, steal syndrome and seroma. CONCLUSION: On the basis of our experience Stretch grafts appear a better option for creating vascular access for HD than Diastat grafts.