A modified technique for bypass of the external carotid artery to the proximal posterior cerebral artery: an anatomical and technical study.

CONCLUSIONS: Our results support the proposition that bypass between the external carotid artery (ECA) and proximal posterior cerebral artery (PCA) can be achieved by using a short saphenous venous graft. The diameters of the ECA and vein graft may provide an increased blood flow with a straighter course. This technique may be helpful for management of patients with vertebrobasilar insufficiency or those requiring a high volume blood flow to the posterior circulation. OBJECTIVES: We aimed to describe a modified technique using a short saphenous vein graft for bypass between the ECA and the PCA in order to use a small length of graft material and increase the patency of the anastomosis. MATERIALS AND METHODS: Ten sides of five cadavers were dissected bilaterally. After a frontotemporal craniotomy and zygomatic arch osteotomy, the middle cranial fossa was exposed. A hole located approximately 2-3 cm posterolateral to the foramen rotunda was created extradurally. The sylvian fissure and the interpeduncular and ambient cisterns were opened. The proximal P2 segment of the PCA was identified. The ECA was found through a cervical incision. A short interposition saphenous vein graft was conducted to pass just behind the ramus mandible to the infratemporal fossa. The bypass between the ECA and P2 segment of the PCA was performed by using a short saphenous vein graft. The diameters of the ECA, P2 segment of PCA and both ends of the saphenous vein graft and its length were measured using an electronic micrometer. RESULTS: The mean cross-clamping time of the PCA was 10.4+/-1.8 min. The mean diameters of the P2 segment of the PCA and ECA were 2.2+/-0.15 mm and 3.83+/-0.28 mm, respectively. The mean length of the saphenous vein graft was 88.8+/-3.8 mm.

Effects of gamma-hydroxybutyrate on cerebrospinal fluid lactate and glucose levels after spinal cord trauma.

This study aims to evaluate the effects of gamma-hydroxybutyrate (GHB) after spinal cord trauma (SCT). Twenty rabbits were divided equally into four groups: group I was the sham-operated group, group II suffered from SCT but received no treatment, group III was given a dose of 400 mg/kg of GHB intravenously before SCT and group IV received the same dose after SCT. Cerebrospinal fluid (CSF) samples were obtained 30 min before SCT (T(0)), at 60 (T(1)) and 120 min (T(2)) after SCT. There was a threefold increase in lactate levels from baseline value at T(2) in group II, while statistically significant elevation of the lactate levels were not observed in groups III and IV. Glucose levels at T(1) and T(2) were significantly lower in groups III and IV compared with the control group. The findings of this study demonstrate that GHB can control the increase of CSF lactate and glucose levels following SCT and that this metabolic effect may be associated with neuroprotective physiological changes.