Ranjit K. Laha

Temporary microvascular clips.

Selected commercially designated temporary clips (Acland, Biemer, Kleinert-Kutz, Variangle, and Yasargil) were applied for 1 hour to rat common carotid arteries. Scanning electron and light microscopic studies revealed varying degrees of endothelial damage. The authors believe that further improvements are needed in the design of temporary clips.

Acute cerebral revascularization following cerebral embolism.

From the of Neurological Surgery, University of Pittsburgh School of Medicine and the Veterans Administration Hospital, Pittsburgh, Pennsylvania, and from the Department of Neurological Surgery, University of California, Davis, Sacramento, California. Supported in part by a grant from the Alcoa Foundation and by a grant-in-aid from the Western Pennsylvania Heart Association. The disability and loss of life resulting from stroke continue to be significant. It has been estimated that thromboembolic cerebral infarcts will cause

Intermittent erection in spinal canal stenosis.

A case of intermittent erection in a patient with spinal canal stenosis is reported. The symptoms disappeared after lumbar laminectomy. The mechanism of erection remains speculative.

Scanning electron microscopic anatomy of the supratentorial basal cisterns.

Arachnoid slips from the canine supratentorial basal cisterns were excised and studied by scanning electron microscopy. The inner face of the arachnoid membrane was examined, and two fundamental surface patterns, fenestrated and embossed, were observed. The remaining fibers and microfibers were anchored to these two surface sheets.

Post-traumatic middle cerebral artery thrombosis.

Post-traumatic thrombosis of the middle cerebral artery (MCA) is uncommon: only 39 cases were found in the literature. In the present report, eight cases of post-traumatic MCA thrombosis are analyzed and compared with other reported cases. The symptoms can be easily confused with those of expanding intracranial hematoma. Although ancillary noninvasive diagnostic methods are helpful, cerebral angiography confirms the diagnosis. The morbidity and mortality rates are high, and treatment has been mainly supportive. The low mortality in the present study may be related to the absence of severe head or other trauma. Possible cerebral revascularization procedures are also discussed.

Antiplatelet Agents in Microvascular Surgery

From the Department of Neurological Surgery, University of Pittsburgh School of Medicine, and the Veterans Administration Medical Center, Pittsburgh, Pennsylvania. Despite advances in instruments, suture materials, and techniques, thrombosis at the anastomotic site is still a problem in microvascular anastomosis. Various pharmacologic agents have been used to inhibit or suppress the process of thrombosis, and the results have been variable. In the present study, a scanning electron microscopic was used to evaluate the roles of aspirin, dipyridamole, and prostaglandin D2 (PGD2) to assess their effects in microvascular anastomosis.

Dorsal longitudinal myelotomy

An evaluation of dorsal longitudinal myelotomy in the management of spasticity of the lower limbs has been done in 17 patients. The follow-up has varied from 1 month to over 2 years. Most patients achieved satisfactory relief from spasticity. Eight patients have died after the operation in chronic care hospitals. In all except one, the spasticity had been relieved. Eight out of the nine living patients have benefited from myelotomy. Recurrence of spasticity following the first operation occurred in four patients, two of whom improved after a repeat myelotomy. In the presence of fixed contractures of the hip and knee joints, a satisfactory clinical result may not be obtained after the myelotomy.

Safe Microclip Occlusive Force for Temporary Vascular Occlusion

A need for refined techniques and instrumentation is becoming more apparent with the widespread application of micro vascular procedures in neurosurgery. Commercially available micro vascular clips currently recommended for temporary small artery occlusion have been substantially improved over the miniature aneurysm clips available previously. Nevertheless, some of these specially designed clips inflict considerable endothelial damage when applied temporarily to small arteries. To date, there are no standard guidelines for a traumatic vascular occlusion; even the minimal force necessary to occlude a small vessel is not known empirically. In our study we evaluated several commercially available temporary micro clips in an attempt to determine the mechanism responsible for endothelial damage.

Effects of contrast media on the canine subarachnoid space.

This study reports an investigation of the canine arachnoid membrane using the scanning electronmicroscope (SEM) regarding the effects of contrast material on these structures. In the normal arachnoid membrane, two basic surface patterns were observed; one fenestrated and the other embossed with parallel fibers. Ventriculography was performed on 30 mongrel dogs divided into five groups: control, air, iophendylate, meglumine iothalamate, and Metrizamide. SEM study of the arachnoid membrane from basal cisterns showed no change after air ventriculography. After contrast agents were used, macrophages appeared and fenestrations became closed with a fibrin-like substance.

Staged middle cerebral artery embolectomy

Abstract Microsurgical MCA embolectomy in our experimental situation seems effective if done within 2 hr postembolism. Embolectomy delayed until 6 hr postembolism was significantly less effective, implying that irreversible, ischemic changes develop during these additional 4 hr. Additional canine MCA embolectomies will be staged at specific time intervals between 2 and 6 hr post-embolism, to determine the maximal time interval within which embolectomy may still be beneficial.