Biomedical subjects

B J Zeeman

Publications and source records attributed to B J Zeeman.

8 recordsLinked to original sources

PubMed1993

Frontoethmoidal meningoencephaloceles: a review of 14 consecutive patients.

Over a period of 4.5 years, 14 patients with frontoethmoidal meningoencephaloceles were treated. Most patients came from Northern Namibia. Precise delineation of all cranial abnormalities was obtained by modern imaging techniques, and specific patterns of cerebral abnormality were found. The malformation was corrected in a single stage, and significant modifications have been developed to render the procedure simpler and safer. Information from our series favors delayed neural tube closure as the primary pathogenesis of the defect and suggests a common teratogen as the most probable etiological agent. Our experience leads us to advocate early correction of even small defects.

Encephalocele↗

PubMed1993

Congenital pseudarthrosis of the tibia--treatment with free vascularised fibular grafts.

Congenital pseudarthrosis is uncommon. We report on a series of 4 patients treated by means of free vascularised fibular grafts. Complications encountered were graft fracture, delayed union and angulation deformities. Modifications in the surgical technique improved later results. We recommend wide excision of pathological bone, bridging of the defect by free vascularised fibular grafts and rigid fixation.

Bone Transplantation↗

PubMed1992

Cutis aplasia.

Explore the source record for details and available documents.

Bone Development↗

PubMed1989

Three dimensional reconstruction in coronal synostosis: pre and post operative appearances.

Three dimensional computed tomography (CT) is a relatively new method of arranging the elements of CT slices into a morphological image with a multi dimensional appearance. It is of particular use in craniofacial deformities. The following report shows its use in the pre and post operative assessment of frontal skull deformity in three infants with coronal synostosis.

Acrocephalosyndactylia↗

PubMed1988

The significance of resection length on the patency rate, and the histopathology, of experimentally avulsed and microsurgically repaired blood vessels.

The significance of resection length on patency rate, and the histopathology, of microsurgically repaired avulsed blood vessels was examined at 3 weeks in two groups of experimentally avulsed rabbit femoral arteries repaired by different surgeons and in a single series of avulsed and repaired veins. All veins were patent 3 weeks after avulsion and microsurgical repair. Histopathology indicated that the vast majority of lesions in veins were removed at resection. Surgeon A achieved 75% patent arteries and Surgeon B achieved 100% arterial patency (resecting 3.7 mm more on average than Surgeon A). Histopathology revealed numerous luminal circumferential lesions remained in the avulsed artery wall following resection. These lesions were sites of smooth muscle cell proliferation and neointima formation. Although similar arterial damage occurs in human avulsion, considerably lower patency rates are achieved for human arterial avulsion repair than were reported in this experimental study. Factors in addition to vessel wall damage must therefore be involved in thrombosis and occlusion of repaired avulsed arteries. Such factors might be lengthy ischaemia time and severe spasm.

Anastomosis, Surgical↗

PubMed1988

The long-term fate of microvenous autografts.

Changes in length, external diameter, wall thickness, and morphology were examined in 60 intraarterial vein grafts and 30 intravenous vein grafts inserted in rabbit femoral vessels. Half of each graft type was explored at 6 or 12 months, giving four experimental groups. The overall patency for intraarterial grafts at exploration was 98 percent and for intravenous grafts 100 percent. In comparison with the initial graft length resected, all four groups were significantly shorter at the completion of anastomosis, and three of the four groups also were significantly shorter at exploration. The overall loss in length of grafts varied between 26 and 30 percent of original length. External diameter was significantly increased (from between 133 and 201 percent) in all four groups at exploration compared to the normal femoral vein. Intravenous grafts maintained normal vein morphology to 12 months. Intraarterial grafts were modified by the ingrowth of smooth-muscle cells from the recipient artery, thereby creating a neointima that significantly thickened their walls at both 6 and 12 months.

Animals↗

PubMed1987

Experimental reclamping of free-flap pedicles: the effect of prolonged stasis on the anastomoses and clamp sites.

The effect of static blood in direct contact with areas of microvascular anastomoses and previous clamp application for prolonged periods of time has been investigated. The free groin flap was used as a model in 27 white rabbits. The flap pedicle vessels were reclamped proximal to the anastomoses and areas of previous clamp application for periods of time varying between 30 minutes and 4 hours after 15 minutes of blood flow over these areas. A 100 percent patency rate was achieved despite the long periods of reclamping. Histologically, minor intimal damage was visible in the immediate period following anastomoses and clamping of the vessels. After 2 weeks, despite a thickened myofibroblastic intimal lesion, an intact endothelial layer was observed. No evidence of thrombosis could be demonstrated in either period. We postulate that vessels carefully treated and with technically well-performed anastomoses can be regarded as "normal" vessels after 15 minutes of blood flow over the anastomoses and clamp sites. We suggest that when required, microvascular clamps may then be reapplied without risk for prolonged periods of time despite static blood being in contact with these areas.

Animals↗

PubMed1985

Effect of stasis on the patency of microvenous grafts in avulsed rabbit femoral vessels.

Seventy femoral arterial avulsions with interpositional microvenous graft repairs were performed in rabbits and were divided into three groups. In Group A clamps were reapplied for 15 minutes with an overall patency rate of 97% after 3 weeks. The overall patency rate in Group B with 30 minutes reclamping was 93% three weeks later. Group C without clamping served as Controls and a 100% patency rate was achieved. The position of the microclamps, static blood in the region of the anastomoses and in the microvenous grafts as well as the time of reclamping up to 30 minutes did not influence the patency rate in damaged vessels after sufficient resection of injured vessel walls. The results of this experiment suggest that if necessary clamps can be reapplied safely in the clinical situation for up to 30 minutes after microvenous grafts have been completed to enable the microsurgeon to perform further dissection in a bloodless field.

Animals↗