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Biomedical subjects

W M Swartz

Publications and source records attributed to W M Swartz.

At least 55 records · Page 3Linked to original sources
PubMed1986

Studies on the nature of the flap/bed interaction in rodents--Part I: Flap survival under varying conditions.

A flap needs close contact with its bed for optimal flap survival. Using a rat dorsal flap model, flap/bed contact times were varied by use of a sterile polyethylene film. In addition, the flap was modified either by removing the panniculus carnosus or by converting the distal flap into a skin graft. Finally, the effect of using a dressing was assessed. Several observations were made: (1) The initial 6 to 12 hours of a flap's interaction with its bed is critical for optimal survival; (2) fluorescein accurately predicted flap survival upon polyethylene removal; (3) removing the panniculus carnosus increased flap and skin graft survival; (4) dressing allowed flaps and skin grafts to better withstand bed deprivation; and (5) distal flaps and skin grafts under various conditions responded differently to bed deprivation.

Animals↗
PubMed1986

Studies on the nature of the flap/bed interaction in rodents--Part II: Morphological and fluorescein kinetic data.

The current study in rats concerns two aspects of the flap/bed interaction: fluorescein kinetics and histological finding. In the control group of animals in the fluorescein kinetics experiment, flaps were raised and then reattached. In one experimental group, the flaps were raised and placed on a sterile polyethylene film. In two other groups, the flaps were raised and then the pedicle was cut, either immediately or at specific intervals. At intervals up to 24 hours several animals were injected with 5% fluorescein. In the control group fluorescein penetration increased with time, while it decreased in the polyethylene-film group. There was virtually no fluorescein staining in both cut-pedicle groups. To study histological events, the animals were divided into groups with flaps and groups in which the distal end of each flap was severed to form a contiguous skin graft. Other conditions were varied. All flaps were cultured, and biopsy specimens were obtained from three areas at several time intervals. Histological sections from the distal flap were markedly different from the corresponding skin grafts. These results corroborate previously noted survival rates.

Animals↗
PubMed1986

The osteocutaneous scapular flap for mandibular and maxillary reconstruction.

Microfil injections in 8 cadavers and clinical experience with 26 patients have demonstrated a reliable blood supply to the lateral border of the scapula based on branches of the circumflex scapular artery. This tissue has been used successfully for reconstruction of a variety of defects resulting from maxillectomy and mandibular defects from cancer and benign tumor excisions. Advantages of this tissue over previous reconstructive methods include the ability to design multiple cutaneous panels on a separate vascular pedicle from the bone flap allowing improvement in three-dimensional spatial relationships for complex mandibular and maxillary reconstructions. The lateral border of the scapula provides up to 14 cm of thick, straight corticocancellous bone that can be osteotomized where desired. The thin blade of the scapula provides optimum tissues for palate and orbital floor reconstruction. There have been no flap failures and minimal donor-site complications.

Adolescent↗
PubMed1986

Pharyngocutaneous fistulas: management with one-stage flap reconstruction.

After total laryngectomy, postoperative pharyngocutaneous fistula still constitutes a most troublesome and challenging problem. We present 9 cases of postoperative fistulas managed by one-stage flap reconstruction. Possible contributing factors related to earlier management or medical status are identified. When the posterior pharyngeal wall was intact in a large pharyngocutaneous fistula, 4 pectoralis major and 2 latissimus dorsi double island musculocutaneous flaps were used. Autogenous jejunal free grafts were used in 3 patients when circumferential reconstruction was required. The cervical esophagus was successfully reconstructed, facilitating swallowing function, in a one-stage procedure in each patient.

Aged↗
PubMed1986

Management of difficult lower extremity fractures and nonunions.

Difficult fractures and nonunions of the lower extremities are defined as compound fractures with soft-tissue loss, segmental bone fractures, and infected nonunions. A variety of methods for managing these defects are presented, including the use of modern fixation techniques and the application of highly vascularized bone and soft tissues. Vascularized bone grafts play a significant role in the treatment of difficult fractures that previously would have required amputation.

Adult↗
PubMed1985

Vascularization of tricalcium phosphate, an artificial bone substitute: preliminary observations.

Tricalcium phosphate (TCP), a biodegradable artificial bone substitute, was used to study the following questions: i) can TCP be vascularized; ii) do ectopically placed implants have osteoinductive capacity; and iii) does vascularization affect implant resorption? Implants were placed in dogs in several areas: i) subcutaneous controls; ii) wrapped with latissimus dorsi muscle; iii) wrapped in omentum; iv) saphenous and thoracodorsal av pedicles threaded through implant. Prior to harvest, animals were given tetracycline and implants were harvested at 3, 6, and 9 weeks. Microfil was injected prior to sacrifice and specimens were xeroradiographed. Histology and computerized axial tomography were obtained. From this study, we conclude that 1) TCP can be vascularized; 2) the most effective method of vascularization was by an AV pedicle threaded through the implant; 3) vascularized implants did not have osteoinductive properties per se, and 4) in the time observed no difference in implant resorption was demonstrated between the test groups.

Animals↗
PubMed1985

The role of free-tissue transfers in lower-extremity reconstruction.

Eighty-five free flaps were performed in 76 patients for defects in the lower extremity. A new classification of lower-extremity defects was devised to help define the role of free-tissue transfers: group 1, soft-tissue defects; group 2, soft-tissue and bone loss less than 8 cm; group 3, massive soft-tissue and bone loss greater than 8 cm; and group 4, bone defect only. Each group was further divided into clean (A) and infected (B) wounds. Our overall results include resolution of the presenting problem in 82 percent; there were 17 flap losses (20 percent), persistent osteomyelitis in 8, and 10 amputations. This review has prompted us to limit our indications for limb salvage, particularly in group 3B, in patients with compound injuries that include loss of plantar sensation, and in patients with large segments of infected bone.

Adolescent↗
PubMed1984

Immediate reconstruction of the wrist and dorsum of the hand with a free osteocutaneous groin flap.

A free osteocutaneous groin flap, based on the deep circumflex iliac artery, was used to primarily fuse the wrist and stabilize the first and second metacarpal bones, as well as provide soft tissue coverage for a severely injured hand. The indications for primary reconstruction with free tissue transfers include a tidy wound with minimal bacterial contamination, ready access to uninjured recipient vessels, and a predictable advantage in the use of free tissue transfer over conventional techniques.

Adult↗
PubMed1984

Limb allografts in rats immunosuppressed with cyclosporin A.

The role of cyclosporin A in transplantation of composite tissue for potential reconstructive purposes is examined in the rat hind limb transplant model. Two inbred rat strains were utilized. Brown ACI rat hind limbs were transferred to the dorsum of white Lewis rats with microvascular anastomoses. Twenty transplants were divided into four groups for postoperative immunosuppression: control, no cyclosporin; 7 days of cyclosporin; 21 days of cyclosporin; and continuous cyclosporin from 44-113 days. Hemagglutination and antibody titers were measured. Clinical evaluation and histologic examination at sacrifice were performed and rejection graded. Cyclosporin A has been successful in suppressing rejection in composite allograft transplant across defined major histocompatability barriers. Rats treated with cyclosporin A for a short period of time showed signs of rejection after discontinuation of therapy. Five animals treated continuously on cyclosporin A for up to 113 days showed no sign of rejection clinically, histologically, or immunologically.

Animals↗
PubMed1984

The results of 39 fractures complicated by major segmental bone loss and/or leg length discrepancy.

Thirty-nine fractures with segmental bone loss and/or limb length discrepancy with defects of 1.8 to 12.0 cm were reviewed retrospectively. Most patients presented with an acute open fracture with segmental bone loss or a late reconstructive problem with a nonunion, frequently complicated by infection, segmental bone loss, and adjacent soft-tissue disruption. One hundred forty-two weeks was the average length of time of treatment before referral of a patient to us. Eighty-eight per cent of the patients received a bone graft that included either autologous cancellous bone, bank bone, a vascularized free iliac crest or fibular transplant, or some combination of these materials. Forty per cent of the patients required some type of soft-tissue coverage such as a split-thickness skin graft, myoplasty, or a free vascularized flap. Seventy-nine per cent of the cases achieved complete osseous and soft-tissue healing within an average of 49 weeks. One patient underwent an above-knee amputation. Almost 80% of all of the patients healed to within 85% or better of anatomic length. Based upon these results a protocol for the management of osseous and soft-tissue defects is outlined which includes debridement, rigid stabilization, and various types of soft-tissue and osseous reconstruction.

Adolescent↗
PubMed1984

The internal oblique muscle flap: an anatomic and clinical study.

A new muscle flap based on the ascending branch of the deep circumflex iliac artery is described. Twenty internal oblique muscle flaps have been dissected and studied in 10 fresh cadavers. This muscle flap has been used successfully as a free-tissue transfer in seven lower extremity defects. There was one loss of flap due to venous thrombosis. Other complications included a local wound abscess (one case), partial loss of skin graft (two cases), and arterial thrombosis (one case). There has been no donor-site morbidity. The donor scars are well concealed and no hernias have been observed, the longest follow-up being 9 months. The additional advantages of this flap include its thin, flat shape, excellent vascularity, and ease of application to areas about the ankle, with good aesthetic results. The disadvantages are (1) bloody and tedious dissection and (2) potential for abdominal weakness or hernia in the long run. This muscle flap appears to be excellent as a free flap for coverage of small- to moderate-sized defects of the distal lower extremity and as a pedicle flap for coverage of soft-tissue defects of the groin and anterior perineum.

Abdominal Muscles↗
PubMed1982

Tumor immunity in rat lymph nodes following transplantation.

Inguinal lymph nodes in the Buffalo rat were autotransplanted to the popliteal fossa by an intact vascular pedicle or by microvascular anastomosis. These revascularized nodes had normal histology and made spontaneous afferent and efferent lymphatic reconnection with surrounding lymphatic vessels, as documented by ink and silicone rubber injection studies. Lymphoscintigraphy with 99mTc antimony sulfide colloid correctly predicted the 44 of 120 node transplants that had made afferent reconnection. To demonstrate immunologic activity of lymph nodes following transplantation, a cellular adherance assay was employed to detect cell-mediated cytotoxicity of lymph node cells isolated from rats sensitized to an allogeneic gliosarcoma. Cytotoxicity was detected in nontransplanted regional nodes sensitized to tumor (p less than 0.01) and in nodes transplanted by vascular pedicle and then sensitized to tumor (p less than 0.001). This study demonstrates that lymph nodes can be transplanted with restoration of functional lymphatic anatomy, and that following transplantation, lymph nodes retain the ability to mount an immune response against tumor.

Animals↗