Electronmicroscopic Changes of Rat's Sciatic Nerve after Phenol Injection or Drip / 대한마취과학회지

BACKGROUND: Phenol is the most commonly used neurolytic agent for the management of intractable somatic pain, but side effects such as motor dysfunction and potential loss of bladder or rectal sphincter function develop following their application. This study observed functional changes of hind limb and neuropathologic changes in the sciatic nerve after phenol application, highlighting the time of nerve regeneration. METHODS: Functional changes in hind limbs were observed for 6 weeks and the distal part of the phenol-injected or dripped sciatic nerve was severed in 3 rats of each group respectively at 10 minutes, 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 4 weeks and 6 weeks. The pathologic changes in the severed nerves were observed under the electron microscope. RESULTS: The phenol-injected or-dripped hind limbs showed more pronounced motor weakness and more obvious gait changes. About 2 weeks after the phenol application, gradual improvement of gait changes began, and after 6 weeks, motor weakness and gait changes were no longer perceptible. In the group with phenol injection, at 10 minutes after injection, destructive lesions were confined to unmyelinated fibers and the myelin sheath of small myelinated fibers. On the 3rd day and at 1 week, pathologic changes on axonal fibers and Schwann cells were in progress with phagocytosis in spite of myelin restitution. From 2 to 4 weeks, axonal regeneration and remyelination appeared concurrent with myelin disintegration and axonolysis, and histologic findings at 6 weeks were similar to those of the control group. In the group with phenol drip, the histologic changes in the sciatic nerve were very similar to the injection group. CONCLUSIONS: These results suggest that histopathologic lesions after a phenol application on the peripheral nerves are not influenced by application methods. The progress of histopathologic changes is obvious according to the time interval following the phenol application. Accordingly, side effectsthat developed following the use of phenol may be improved around the time when the nerve regeneration occurs, between the second and fourth weeks after the injection. The course of histopathologic changes and clinical findings following the application of phenol is very similar to the previous experiment using alcohol.

Anatomy of Human Epidural Space using CT-epidurography / 대한마취과학회지

The anatomy of the human epidural space was demonstrated in 8 patients by computed tomography (CT) examinations performed after epidural injection of water soluble radiographic contrast material into the L3-4 epidural space via Tuohy needle. The examinations showed the posterior epidural space to be divided by the plica mediana dorsalis and an additional transverse connective tissue plane. The compartmentalized nature of the space may be, at times, responsible for entrapment and coiling of epidural catheters, despite the satisfactory technical performance of catheterization for epidural anesthesia. All patients demonstrated a great amount of fatty tissue within the junction of the posterior midline epidural connective tissue structures, producing a triangular-shaped structure which might be an impediment to catheterization. The posterior epidural space is more easily filled with contrast media than the anterior epidural space. We also measured the depth of epidural space. The posterior epidural space was 2-6 mm deeper than the anterior epidural space. At the thoracic spine, the depth of the posterior epidural space was about 1-2 mm and the anterior space was under 1 mm or revealed trace. At the lumbar region, the depth of the posterior epidural space was about 4-7 mm. Air bubbles were noticed in the epidural space, especially around intervertebral foramen; therefore, it was suggested that the air bubbles can produce incomplete analgesia along the nerve roots.

Control of Intraoeular Pressure by Intravenous Lidocaine Pretreatment / 대한마취과학회지

It is a known fact that the increase of intraocular pressure results from the action of succinylcholine, endotracheal stimulation to carina, bucking and coughing etc during the induction arid recovery periods. Efforts have been made by several inveatigators to prevent intraocular hypertension by giving trimetaphan, inderal or curare. However, their effects were not remarkable. In this study, lidocaine Img/tg was administered intravenously to selectee patients 2-3 minutes hefore induction ; followed by regular induction with pentothal, succinylcholine and incubation. Intraocular pressures were measured at the pre-induction and post-intutation time, and every 30 minutes until the early recovery period, thereafter. The result of this study showed that the post-intubational increase of intraocular pressure was prevented in 86.7% of the lidocaine pretreated cases. The increase of post-extuba-tional intraocular pressure was also reduced significantly in the lidocaine pretreated group-as well. We came to the conclusion that lidocaine pretreatment technic can be used effectively to prevent intraocular hyperteilsion caused by induction and extubation in clinical practice.