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Biomedical subjects

W M Swartz

Publications and source records attributed to W M Swartz.

At least 19 recordsLinked to original sources
PubMed1992

Attenuation of reperfusion-induced lipoperoxidation by systemic use of oxygen radical scavengers after pedicle occlusion.

Oxygen free radicals are implicated to cause tissue injury during ischemia and reperfusion and may play a central role in the no-reflow phenomena. Modulation of these substances has been suggested as a means of decreasing the amount of tissue loss due to ischemia and subsequent reperfusion. Pretreatment of tissues with a variety of agents has been reported to minimize the production of oxygen radicals and augment tissue survival after an ischemic insult. Ischemic clinical situations, however, usually present unexpectedly and thus pretreatment is not feasible. Our study evaluated the activity and effect of free radical scavengers delivered systemically during the ischemic interval to an ischemia/reperfusion rat intestinal model. Superoxide dismutase and dimethylthiourea were given systemically after occlusion and reperfusion to simulate a clinical sequence of a failing flap, that is, the vascular compromise, the diagnosis, and the successful resolution of the vascular embarrassment. Measurements of malonyldialdehyde (MDA), the end product of lipoperoxidation of cell walls, were compared with controls. Tissue histology was assessed and correlated with the use of these agents. A third group of rats was systemically alkalinized to attempt to shift the Bohr curve and decrease free oxygen substrate in the ischemic tissues on reperfusion. Rats treated with superoxide dismutase and dimethylthiourea showed significant reductions of MDA compared with nontreated rats (p less than 0.05), indicating attenuation of reperfusion lipoperoxidation. Systemic alkalinization of the rats did not significantly change the levels of MDA. Tissue histology showed severe injury in all ischemic groups regardless of the level of MDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Cost analysis of microsurgical reconstruction in the head and neck.

In a cost-conscious environment, pressure exists to justify the use of expensive techniques such as reconstructive microsurgery in head and neck patients. Therefore, the costs and effectiveness of 39 consecutive free tissue transfers in patients with head and neck defects due to neoplasia (77%), trauma (13%), or congenital causes (10%) were assessed by reviewing clinical and billing records. The technical success rate was 95% with a 29% rate of complications. Most patients returned to preoperative levels of social activities, and none admitted dissatisfaction with their results. Average cost was $27,000 per case with 16 days of hospitalization. Average cost for aerodigestive tract tumors was $37,400 with 21 days of hospitalization. Costs were directly related to the etiology of the defect and incidence of complications. Applying cost-effectiveness principles we believe that these costs are justified by the high level of patient satisfaction and enhanced quality of life.

Adult↗
PubMed1990

Expanding the horizons in treatment of severe peripheral vascular disease using microsurgical techniques.

The use of microvascular tissue transfer as an adjunct to arterial reconstruction has begun to have a positive impact on limb salvage in patients with advanced arteriosclerosis and nonhealing ischemic wounds. However, many patients with severe peripheral vascular insufficiency not amenable to conventional arterial reconstructive procedures eventually require limb amputation. We have treated 12 patients with advanced peripheral vascular disease and nonhealing ischemic wounds by three different methods. These included distal bypass alone, distal bypass done in conjunction with free-tissue transfer, and free-tissue transfer alone. All bypass grafts were done to vessels at or below the ankle using a reversed saphenous vein. In each case, the distal anastomosis was performed, using the operating microscope and standard microvascular technique. Mean follow-up for these patients is 18 months. Distal bypass alone resulted in limb salvage in three of five patients. In the combined bypass and free-flap group, three of five patients had salvage of their threatened extremity at a 1-year follow-up. Two patients with ischemic ulcers, rest pain, and unsuitable distal vessels for bypass were treated with free-tissue transfer alone. This resulted in healed wounds, limb salvage, and complete resolution of the rest pain symptoms in both patients. When advanced ischemia is complicated by large areas of tissue loss, combined bypass and microvascular free-issue transfer, performed in stages or simultaneously, is safe and can often result in limb salvage. In the rare instance of a completely obliterated distal runoff bed, free-tissue transfer alone may provide not only a healed wound, but also a means of "indirect" revascularization of the extremity and limb salvage.

Aged↗
PubMed1990

The survival and nature of the immune response to soft-tissue and composite-tissue allografts in rats treated with low-dose cyclosporine.

We studied a variety of soft-tissue and composite-tissue allografts (CTA) in a histoincompatible rat model to determine the outcome and the nature of the immunologic responses to these tissues using continuous low-dose cyclosporine (CsA) therapy. Brown-Norway (RT1n) rats served as donors of soft tissue and CTA to Lewis (RT1l) rat recipients given low-dose CsA immunosuppressive therapy by gavage. Nine groups were studied. Three control groups were not treated with CsA: group 1, skin grafts alone; group 2, skin flaps alone; and group 3, skin grafts and delayed vessel allotransplants. Six groups were treated with CsA: group 4, skin grafts alone; group 5, skin flaps alone; group 6, skin grafts and delayed vessel allotransplants; group 7, aortas alone; group 8, muscle flaps alone; and group 9, bone grafts alone. Isografts were performed in all groups as technical controls. The appearance posttransplant of donor-directed cytotoxic antibodies was determined in recipient serum using a complement-mediated cytotoxicity assay and was compared to control and pretransplant sera. In the absence of CsA therapy, recipients in groups 1, 2, and 3 rejected their allografts early (8.5-9.4 days) and developed profound antidonor cytotoxic antibody activity posttransplant by day 7. Groups 4, 5, 6, 7, and 9 had prolonged graft survival in the presence of low-dose CsA, despite the presence of antidonor antibody activity. By contrast, group 8 (muscle flaps) were all uniformly rejected in the presence of profound recipient cytotoxic antidonor antibody activity. These results suggest that long-term soft-tissue and CTA survival can be achieved in histoincompatible rat recipients using continuous low-dose CsA immunosuppressive therapy despite the presence of cytotoxic antidonor antibodies.

Animals↗
PubMed1990

Refinements in free flaps for head and neck reconstruction.

The decade of adolescence of microsurgical techniques of head and neck reconstruction has led to a further clarification of the indications and methods for microsurgical reconstruction of head and neck defects. A review of the defects and the variety of flaps available for reconstruction leads to an increased understanding of the advantages and disadvantages of these various methods. When assessing a defect in the head and neck for microsurgical reconstruction, the surgeon should consider the various advantages of the flap to be used and weigh them against the disadvantages. The specialty has long since passed the point when one or two donor flaps could be considered to answer all of the reconstructive questions. We must now thoughtfully consider all the available options before settling on a course of treatment.

Esophagus↗
PubMed1989

Experimental and clinical monitoring of free jejunal transfers using an implantable ultrasonic Doppler probe.

Postoperative assessment of the continued viability of a "buried" free jejunal transfer remains a difficult problem. The reliability of a 20 MHz pulsed ultrasonic Doppler probe to detect arterial or venous occlusion has been investigated experimentally in isolated vascularised jejunal segments in dogs. Clinically, the probe has been used intraoperatively to confirm normal flow in both the mesenteric artery and mesenteric vein of free jejunal transfers. Continuous recording of the acoustic signal from the probe during closure of the incisions has allowed immediate detection of any adverse effect due to pedicle kinking or excessive skin tension. Sixteen patients undergoing free jejunal transfer have been monitored continuously using the implantable 20 MHz pulsed ultrasonic Doppler probe positioned on the inflow mesenteric artery.

Animals↗
PubMed1989

Mycetoma of the hand.

Mycetoma or maduromycosis is a rare chronic granulomatous disease caused by a fungus infection. We report a rare case of mycetoma in the hand; to our knowledge this is the first report in the United States of mycetoma caused by Nocardia asteroides. The patient had had 2 years of chronic drainage and edema of the left hand after a penetrating injury sustained in the shipyards. After surgical debridement he was treated with co-triamazole, 1 tablet orally four times a day for 6 months. The chronic drainage has ceased but most of his wrist and hand joint movements are restricted.

Hand↗
PubMed1989

Restoration of sensibility in mutilating hand injuries.

The restoration of hand sensibility should be a high priority in providing soft tissue coverage for extensive hand injuries. Initial wound management may be effectively provided by conventional techniques, including skin grafts and groin flaps as a first stage. Once the magnitude of the injury is determined and the reconstructive goals are established, many of these procedures can be performed at a second operation. More circumscribed tissue losses, in which restoration of sensibility is the primary reconstructive goal, may be addressed in the acute or semiacute setting with primary sensory flap reconstructions. The advantage of this approach is that dissection of vessels and nerves is generally easier without the problems of scarring and fibrosis, thereby significantly hastening functional recovery.

Finger Injuries↗
PubMed1988

Rat surgery board.

Our microsurgery laboratory needed a number of surgical rat boards, and considering the expense of the ones already on the market, we decided to make our own. A 14 in x 10 in board was cut from a large Plexiglas sheet. Suction cups with metal hooks were used to hold the rat in place. We found this board to be less expensive and also very versatile.

Animals↗
PubMed1988

Microvascular approaches to nasal reconstruction.

In summary, the use of free tissue transfers for nasal reconstruction offers a wide variety of tissues that provide cutaneous coverage, underlying support, and nasal lining. Obtaining the final aesthetic result frequently requires defatting and other touch-up procedures, which usually can be done under local anesthesia on an outpatient basis.

Aged↗
PubMed1988

Primary lymphedema of the scrotum: surgical treatment and reconstruction.

Lymphedema of the penis and scrotum has significantly functional, cosmetic, psychological, and possibly malignant consequences for the affected patient. The authors have treated 3 patients with lymphedema of the scrotum by radical excision of all lymphedematous scrotal tissue and reconstruction using posterolaterally based scrotal flaps. Patients have been followed for six months to one year: There has been no recurrence of lymphedema. No complications were encountered, and cosmetic results were satisfactory.

Adult↗
PubMed1988

Direct monitoring of microvascular anastomoses with the 20-MHz ultrasonic Doppler probe: an experimental and clinical study.

The 20-MHz ultrasonic Doppler probe was used to determine its efficacy as a continuous monitoring technique for microvascular anastomoses. A 1-mm2 piezoelectric crystal embedded in a soft silicone sleeve was sutured directly to the blood vessel distal to the anastomosis. Using the dog femoral artery, simultaneous measurement of velocity and blood flow with an electromagnetic flowmeter established a direct correlation between flow and velocity with a 14 percent error at maximum flow and an 18 percent error at minimum flow conditions. The probe was then implanted in the rabbit femoral artery for 1 week (n = 3) and 4 weeks (N = 6), demonstrating that a continuous tracing could be obtained without injury to the vessel. Our clinical study included 63 patients undergoing free-tissue transfers monitored with the implantable probe for 7 to 29 days (average 10.5 days). Twenty-three flaps were buried. Two patients experienced loss of arterial tracing due to malfunction of the probe (3 percent). Three patients had a venous thrombosis with a present arterial tracing. There were no flap failures per se. All probes were removed without mishap, and there were no complications related to the probe. We conclude that the 20-MHz ultrasonic Doppler probe holds promise as a useful monitoring method.

Anastomosis, Surgical↗
PubMed1988

The critical relationship between free radicals and degrees of ischemia: evidence for tissue intolerance of marginal perfusion.

UNLABELLED: Skin-flap ischemia has been associated with the presence of free radicals. In this study, two enzyme systems involved in free-radical metabolism were used to compare a distal skin flap to a skin graft. Forty-two rats were divided into several test groups. A 10 X 3 cm dorsal rat flap was used, and tissue biopsies for xanthine oxidase and malonyldialdehyde (MDA) were obtained 2.5, 5.5, and 8.5 cm from the base of the flap at the hours given. In group I (control), the flap was outlined but not elevated, and biopsies were obtained. In group II, the flap was elevated, and biopsies were obtained at 6 hours. In group III, the flap was elevated, the distal 4 X 3 cm was amputated and replaced as a full-thickness skin graft, and biopsies were obtained at 6 hours. In group IV, the flap was elevated, and biopsies were obtained at 12 hours. In group V, the flap was treated as in group III, and biopsies were obtained at 12 hours. In group VI, the flap was elevated, and biopsies were obtained at 24 hours. In group VII, the flap was treated as in group III, and biopsies were obtained at 24 hours. RESULTS: Xanthine oxidase was significantly higher in all distal biopsies compared to proximal biopsies. Xanthine oxidase also increased with time. Malonyldialdehyde increased over time as well as with distance from the flap base. Distal flap biopsies at 24 hours had greatly increased levels of malonyldialdehyde compared to skin grafts (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1988

The "double barrel" free vascularized fibular bone graft.

A further modification of the free vascularized fibular bone graft is described in which a transverse osteotomy is made from the anterolateral aspect of the fibular shaft just distal to the entry of the nutrient artery. This produces two vascularized bone struts that may be folded parallel to each other but that remain connected by the periosteum and muscle cuff surrounding the peroneal artery and vein. The proximal strut is vascularized by both a periosteal and an endosteal blood supply, whereas the distal strut is vascularized by a periosteal blood supply alone. This so-called "double barrel" free vascularized fibular graft has been employed in three patients with segmental bone defects of the distal femur and in one patient with adjacent bony defects of the radius and ulna.

Adult↗
PubMed1988

Extensive and complex defects of the scalp, middle third of the face, and palate: the role of microsurgical reconstruction.

Twenty-one patients with gigantic defects of the scalp and middle third of the face and palate following excision of neglected or recurrent tumors, burns, and infections have undergone microsurgical reconstruction. Wide resection of the middle third of the face, orbit, and palate requires "complex" three-dimensional volume reconstruction, whereas extensive defects of the scalp and skull (exceeding 80 cm2) require coverage of the larger surface area soft-tissue defect and the exposed brain and dura. The latissimus dorsi free-muscle flap and split-thickness skin graft have become our methods of choice for extensive scalp and skull defects. The latissimus dorsi musculocutaneous free flap is preferable for reconstruction of complex palatal and external skin and orbital defects of the middle third of the face. Microsurgical free-tissue transfer reliably frees the oncologic surgeon from the constraints imposed by conventional reconstructive techniques and may therefore allow improved curative or at least palliative resection of these extensive tumors.

Adult↗