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Biomedical subjects

C R Lye

Publications and source records attributed to C R Lye.

9 recordsLinked to original sources

Chronic mesenteric ischemia.

Although chronic mesenteric ischemia is an infrequent, even rare, condition and a busy vascular surgeon may encounter only one such patient in a year, the associated morbidity and mortality are high, especially if the condition is not recognized. General and vascular surgeons must bear in mind the triad of postprandial pain, weight loss and diarrhea. Patients with mesenteric ischemia are at high risk and generally have diffuse peripheral vascular disease. Although surgery is hazardous, successful repair can result in long-term survival without morbidity. The author favours antegrade supraceliac bypass grafting over infrarenal grafting which is technically more difficult.

Chronic Disease

Peripheral nerve injuries during carotid endarterectomy.

Peripheral nerve injuries associated with carotid endarterectomy are fairly common but not emphasized in reported results of carotid endarterectomy. The sensory nerves to the submandibular skin and ear lobe are often damaged. Motor nerves VII, IX, X, XI and XII may be injured at surgery. The commonest motor injuries involve the facial, vagus and hypoglossal nerves. Carotid endarterectomy was studied prospectively over 1 year to document the incidence of nerve injury. Nerve injury occurred in 12% of patients, with facial and vagus nerves being involved in 4% each. Careful surgical technique based on appropriate anatomical knowledge can prevent most of these complications.

Carotid Arteries

Inflammatory abdominal aortic aneurysm.

The inflammatory abdominal aortic aneurysm has received little attention in the literature. To date only four reports have addressed the subject specifically. Controversy remains as to whether this is a variant of the usual atherosclerotic aneurysm or a separate entity. The operative reports of 24 patients with inflammatory abdominal aortic aneurysms are reviewed; 21 were intact and 3 ruptured. Intact aneurysms ranged in diameter from 5 to 12 cm and the ruptured ones from 5 to 10 cm. Nine patients with intact aneurysms had symptoms of abdominal or back pain. Of 13 patients who underwent excretory pyelography before operation, only 3 had evidence of obstruction. Nine patients had tube grafts placed, 10 had aortoiliac grafts and 5 aortofemoral grafts. There was one intraoperative duodenal injury and in another patient it was necessary to divide the left renal vein for proximal exposure. No attempt was made to expose the ureters at operation. All patients were discharged from hospital. The authors believe that the inflammatory aneurysm is a variant of the abdominal aortic arteriosclerotic aneurysm. Intraoperative complications can be avoided by the recognition of the pathological features.

Aged

The effects of femoropopliteal vein graft failure on limb function.

Twenty-one patients were followed for an average of 40 months following occlusion of femoropopliteal vein grafts. Serial recordings of the resting ankle pressure index and treadmill walking time were correlated with the patient's clinical status, and compared to the preoperative values. Graft failure resulted in a return to preoperative status in ten of 11 limb salvage patients. There were 5 amputations, 3 died of unrelated causes, and 2 were subsequently improved by further reconstructions. At last followup, 3 of 10 patients who were operated on for claudication were unchanged, 6 were improved, and one became worse. In no case did graft failure result in the development of advanced ischemia. Femoropopliteal graft failure did not have a significantly adverse effect on limb function or survival in patients presenting with claudication, nor did it complicate the subsequent course of patients in whom the initial aim was limb salvage.

Adult

The accuracy of the supraorbital Doppler examination in the diagnosis of hemodynamically significant carotid occlusive disease.

The supraorbital Doppler technique was used to study 102 carotid arteries prior to arteriography. A carotid stenosis was defined as being hemodynamically significant if the diameter of the lumen were reduced by more than 50 percent. The Doppler examination gave a false-positive result in only two of the 61 arteries which did not demonstrate significant stenoses. False-negative Doppler results occurred in 22 percent of the 41 significant carotid lesions. The presence or absence of significant carotid lesions were predicted in 96 percent of 67 arteries for which the results of the supraorbital examination and carotid auscultation were in agreement. False-negative results occurred in association with significant ipsilateral external and common carotid stenoses and in the presence of unusually efficient collateral circulation via the circle of Willis. The supraorbital Doppler examination is a valuable technique for the identification of patients with hemodynamically significant carotid stenoses.

Adult

Aortorenal arterial autografts.

Forty-nine iliac artery autografts were used in the treatment of renovascular hypertension in 45 patients, including six children. The pathological process was fibromuscular dysplasia in 42, atherosclerosis in two, and Takayasu arteritis in one. The internal iliac artery was used as a graft in 39 patients. The common iliac bifurcation was used in two patients, and the external iliac artery in four patients. Common and external iliac artery continuity was restored with Dacron prostheses. Forty-three patients with 47 autografts have been followed up from one to ten years (average three years). Hypertension was cured or improved in 96% of the patients. Serial follow-up arteriograms as late as ten years after surgery have been obtained in 50% of the patients. No late occlusions occurred. Slight autograft dilation occurred seven years postoperatively in one child. Normal growth of the autograft was exhibited in the remaining five children. No evidence of dilation, aneurysm formation, or stenosis appeared in any other grafts, although one patient developed a new lesion distal to her graft.

Adolescent

The transcutaneous measurement of the elastic properties of the human saphenous vein femoropopliteal bypass graft.

The pressure-strain elastic modulus and compliance of 20 reversed saphenous femoropopliteal vein grafts have been measured by a noninvasive, ultrasonic method. The grafts had been in place for an average of 33.6 months, 11 days to 128 months. In this study no correlation was demonstrated between wall stiffness and duration of implantation. It is concluded that the elastic properties of vein grafts may remain stable for considerable periods of time.

Adult