Electron microscopic study of the myelinated nerve fibres and the perineurial cell basement membrane in the diabetic human peripheral nerves

To study the quantitative and ultrastructural changes in myelinated nerve fibers and the basement membranes of the perineurial cells in diabetic nerves. The study was performed at the Department of Anatomy, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Saudi Arabia from 2003 to 2005. Human sural nerves were obtained from 15 lower limbs and 5 diabetic nerve biopsies. The total mean and density of myelinated nerve fibers per fascicle were calculated, with density of microtubules and mitochondria in the axoplasm. The number of the perineurial cell basement membrane layers was counted, and thickness of the basement membrane was measured. Among the 15 diabetic and 5 normal human sural nerves, the average diameters, number and surface area of myelinated nerve fibers and axonal microtubules density were found to be less in diabetic nerves. Mitochondrial density was higher in diabetic axons. Thickness of the perineurial cell basement membrane had a greater mean, but the number of perineurial cell layers was less than that of the diabetic group. The inner cellular layer of the perineurium of the diabetic nerves contained large vacuoles containing electron-dense degenerated myelin. A few specimens showed degenerated myelinated nerve fibers, while others showed recovering ones. Retracted axoplasms were encountered with albumin extravasation. Diabetes caused an increase in perineurial permeability. The diabetic sural nerve showed marked decrease in the myelinated nerve fibres, increase degenerated mitochondria, and decreased microtubules

Ultrastructural changes of compressed lumbar ventral nerve roots following decompression

To study whether there will be a permanent lumbar nerve root scarring or degeneration secondary to continuous compression followed by decompression on the nerve roots, which can account for postlaminectomy leg weakness or back pain. The study was performed at the Department of Anatomy, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia during 2003-2005. Twenty-six adult male New Zealand rabbits were used in the present study. The ventral roots of the left fourth lumbar nerve were clamped for 2 weeks then decompression was allowed by removal of the clips. The left ventral roots of the fourth lumbar nerve were excised for electron microscopic study. One week after nerve root decompression, the ventral root peripheral to the site of compression showed signs of Wallerian degeneration together with signs of regeneration. Schwann cells and myelinated nerve fibers showed severe degenerative changes. Two weeks after decompression, the endoneurium of the ventral root showed extensive edema with an increase in the regenerating myelinated and unmyelinated nerve fibers, and fibroblasts proliferation. Three weeks after decompression, the endoneurium showed an increase in the regenerating myelinated and unmyelinated nerve fibers with diminution of the endoneurial edema, and number of macrophages and an increase in collagen fibrils. Five and 6 weeks after decompression, the endoneurium showed marked diminution of the edema, macrophages, mast cells and fibroblasts. The endoneurium was filled of myelinated and unmyelinated nerve fibers and collagen fibrils. Decompression of the compressed roots of a spinal nerve is followed by regeneration of the nerve fibers and nerve recovery without endoneurial scarring

Anatomical study of the round ligament approach to segment III duct of the liver

The duct of segment III of the liver has been used as a conduit to the jejunum in cases of hilar biliary obstruction. Twenty five fresh livers were studied. The bile duct-common hepatic or common bile-, the hepatic artery and the portal vein were injected with latex and dissected to display the anatomy of the round ligament approach to segment III duct. The round ligament approach was attempted in six patients operated upon for hilar biliary stricture. In ten specimens [40%], the duct of segment III passed from its sheath and followed the left side of the left portal branch posterosuperiorly in the fissure for ligamentum teres till the origin of the sheath of segment II where it changed its direction to the right to run above and behind the left portal branch in the porta hepatis [the pattern of the curved duct]. In 9 specimens [36%], the duct of segment III passed from its sheath directly to the right in front of the left portal branch just proximal to its junction with the round ligament on its way to the left end of the porta hepatis [the pattern of straight duct]. In 6 specimens [24%], segment III was drained by two ducts [the pattern of double duct]. In the six cases operated upon, the duct could not be reached in a cirrhotic patient, three patients had straight ducts which were easily exposed, one patient had the curved duct pattern which was exposed with great difficulty, and in one patient a hepatotomy was done to reach the duct