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Biomedical subjects

S J Mathes

Publications and source records attributed to S J Mathes.

At least 55 records · Page 3Linked to original sources

Comparison of the intracellular bacterial killing activity of leukocytes in musculocutaneous and random-pattern flaps.

The in vivo physiologic response to gram-negative bacterial inoculation within wound cylinder spaces enclosed by the deep surface of paired musculocutaneous and random-pattern flaps was studied in the canine model. Leukocyte function was assessed by calculating the following values: leukocyte counts, bacterial counts, phagocytic indices, and intracellular bacterial killing ratios. The following results were observed in the wound cylinder spaces after bacterial inoculation with 5 X 10(7) of Pseudomonas aeruginosa bacteria: (1) the numbers of mobilized leukocytes within each wound cylinder space flap were not statistically different, (2) the bacterial counts were significantly lower in the musculocutaneous flap wound cylinder space at both 24 and 48 hours, (3) the phagocytic activity of the leukocytes within musculocutaneous flap wound cylinder space was 1.5 times greater than the leukocytes in the random-pattern flap wound cylinder space, and (4) the intracellular bacterial killing ratio of the musculocutaneous flap leukocyte was 83 percent versus 26 percent in the random-pattern flap leukocyte, a significant difference.

Animals↗

Long-term effects of tissue expansion on cranial and skeletal bone development in neonatal miniature swine: clinical findings and histomorphometric correlates.

Progressive tissue expansion induces significant gross, histologic, and bony changes in skulls and long bones of neonatal miniature swine. These bony changes consist of erosion underlying tissue expanders, with bony lipping and bone deposition at the periphery of the expander. Cranial suture lines underneath expanders appear effaced and convoluted. Serial CT scans reveal decreased bone thickness and volume (p less than 0.02) but identical bone density (p = 0.60) beneath expanders. Increased bone volume and thickness occur at the periphery of expanders (p less than 0.02). Bone density (CT number) is unaffected by tissue expansion in both cranial and long bones. These findings have histomorphometric correlates: Osteoclastic bone resorption occurs underneath expanders with periosteal reaction at the periphery of expanders. Cranial sutures are similarly affected, but no cranial synostosis results. No changes to the inner table of the skull or stigmata of increased intracranial pressure were observed either in CT scans or in behavioral changes in long-term animals. The pathophysiology of bony changes is a remodeling effect, not one of simple pressure deformation. Increased bone resorption and complete inhibition of bone formation occur until the pressure is removed. Cranial bone is significantly more affected than long bone. After removal of the expanders, reparative bone remodeling begins within 5 days and nearly complete healing of the cranial defects occurs within 2 months (p less than 0.02). No plagiocephaly results despite early coronal suture changes. On the basis of this study, we conclude that tissue expansion causes significant but reversible effects, readily monitored by high-resolution CT scans, on neonatal and infant cranial and long bones.

Animals↗

Blood supply of the upper extremity muscles as related to functional tendon transfers.

For a given function to be restored, we feel that a "low risk" muscle should be employed in preference to a "high risk" muscle. If a "high risk" muscle must be used, a knowledge of its segmental blood supply should lead one to proceed with careful dissection (even under magnification), wider exposure, and preservation of every possible distal pedicle. We would strongly discourage blind "stripping" of the muscle belly in "high risk" muscles. This technique could be employed almost with impunity in the "low risk" muscles. We realize that this is a static, purely anatomic study with a new, theoretical viewpoint of tendon transfer techniques. Other factors must be considered (expendability, muscle strength, synergism, and amplitude). However, we feel that results may be improved through application of these detailed anatomic data. We have attempted to better delineate the blood supply to the muscles of the upper extremity. This knowledge may help improve our results in functional tendon transfer procedures.

Arm↗

Biologic priming of neutrophils in subcutaneous wounds.

Migration of neutrophils from blood into tissue is a complex response by circulating cells to chemotactic stimulation. Previous studies of the functional changes induced by this process have produced variable results. We compared neutrophils isolated from blood and from subcutaneous wounds in rabbits using established assays for adherence, chemotaxis, superoxide anion production, and hydrogen peroxide production. No differences in adherence to biologic surfaces or chemotaxis toward activated plasma were found. However, our results confirm the observation that wound neutrophils are "primed" for increased production of oxygen radicals. Primed responses were observed for both soluble (formyl methionyl leucylphenylalanine, phorbol myristate acetate) and particulate (opsonized zymosan) stimulants. Priming was also observed for peritoneal exudate neutrophils. The data suggest that the process of extravascular migration includes priming of the superoxide generating system.

Animals↗

Reconstruction of posterior neck and skull with vertical trapezius musculocutaneous flap.

The vertical trapezius musculocutaneous flap has been successfully utilized for reconstruction in 13 patients with complex posterior skull and neck defects. This flap based on its vascular pedicle, the descending branch of the transverse cervical artery, provides well-vascularized tissue for coverage of defects related to chronic osteomyelitis, tumor extirpation, osteoradionecrosis, and dehisced cervical laminectomy wounds. Emphasis on flap design, including the location of the skin island, allows adequate wound coverage, direct donor site closure, and muscle function preservation. With its large size and wide arc of rotation, the vertical trapezius musculocutaneous flap provides reliable coverage for posterior trunk, cervical, and skull defects.

Back↗

Distal avulsion of the palmar plate of the interphalangeal joint of the thumb.

A 63-year-old woman was unable to actively flex the interphalangeal joint of her right thumb after a hyperextension injury. Surgical exploration revealed an avulsion of the distal insertion of the palmar plate, allowing the bulk of the plate to block the joint during attempted active flexion. Resection of the palmar plate restored active flexion and caused no joint instability. We do not believe this lesion, which resulted in this disability, has been previously described.

Cumulative Trauma Disorders↗

Oxygen as an isolated variable influences resistance to infection.

The relative importance of oxygen in relation to resistance to infection was assessed in 24 mongrel dogs. Rectus abdominis musculocutaneous (MC) and corresponding cutaneous random pattern (RP) flaps based at the level of the xiphoid were elevated, replaced, and sutured. Immediately after the surgical procedure, 0.1 ml saline containing 10(8) Staphylococcus aureus/ml was injected intradermally into six fields of each flap. After the operation, the dogs were caged in controlled environments with different oxygen concentrations at 12%, 21%, and 45% for 3 days. After 24, 48, and 72 hours, lesion size was measured. Different lesion size was noted between the hypoxic and the hyperoxic groups in the MC flaps from the first day on and in the RP flaps from the second day on (p less than 0.05). Resistance to infection with S. aureus is oxygen dependent, particularly when tissue PO2 is below 40 mmHg.

Animals↗

The V-Y plantar flap for reconstruction of the forefoot.

Stable reconstruction of the forefoot remains a formidable challenge. The present study reviews our experience with a flap of plantar skin and fascia advanced in a V-Y manner to cover metatarsal head ulcers. Although this technique was used in a variety of clinical situations, 71 percent of the 38 patients were diabetic with neurotrophic wounds. The anatomic basis for flap design is reported based on 10 fresh cadaver dissections. Flap survival was 100 percent. Ulcer recurrence was related to the problems inherent in the hypesthetic foot. We feel that judicious manipulation of the bony architecture along with weight-dispersion shoe inserts assists in preventing recurrent ulceration.

Adolescent↗

Vascular anatomy of the upper extremity muscles.

This study delineates the vascular anatomy of the upper extremity with particular attention toward the size, location, and number of vascular pedicles supplying each muscle. Ten cadaver upper extremities were dissected. A total of 440 muscles and 2209 pedicles were identified. The major "named" arterial source, number of pedicles, and pattern of perfusion for each muscle were delineated. Detailed description of the vascular anatomy of muscles commonly used for tendon transfer and local flaps is presented. The potential use of the coracobrachialis flap for contouring the infraclavicular area is elucidated. The anatomic bases of the anconeus and flexor carpi ulnaris flaps are confirmed. The radial and ulnar arteries may be used as microvascular donor or recipient vessels without compromising forearm muscle perfusion.

Adult↗

Tissue oxygen measurements in delayed skin flaps: a reconsideration of the mechanisms of the delay phenomenon.

The delay phenomenon was studied by measuring tissue oxygen tension (PsqO2) for 3 weeks in delayed flaps and normal adjacent contralateral skin in seven mongrel dogs. The PsqO2 fell after elevation of a bipedicle flap and rose again to normal by day 14. Delivery of oxygen to this flap was improved by surgical delay, so that when the bipedicle flap was reelevated on day 14 and its distal pedicle divided, minimal changes in PsqO2 occurred. When the control area was elevated on day 14 as a random-pattern flap, it had higher PsqO2 values than measured in the bipedicle flap on day 0, and therefore, it too had participated in the delay phenomenon, even though only its midline edge had been incised. An anatomic explanation for the findings was sought in wounds made in 10 rabbit ear chambers. After injury, blood flow was seen to be rerouted parallel to the incision line and was increased first by vasodilation and then also by angiogenesis until about day 14. Rerouting of blood by injury, inflammation, and angiogenesis due to repair appears to account for a significant portion of the delay phenomenon.

Animals↗

Preservation of projection after reduction mammaplasty: long-term follow-up of the inferior pedicle technique.

In reduction mammaplasty by the inferior pedicle technique, the dermal-breast pedicle can be manipulated to form a central breast mound and enhance breast projection. When this technique is applied both to macromastia and breast asymmetry, excellent early results are reported. To study the effects of time on breast reduction, 22 patients were followed for an average of 4.7 years. Contour of the breast mound and projection are well preserved. However, evaluation of long-term results reveals a gradual increase in the inframammary fold to inferior areola distance. Since no increase in the midclavicle to nipple distance is observed, inferior migration of the breast parenchyma and superior displacement of the nipple-areola with respect to the breast mound occur after reduction mammaplasty with the inferior pedicle technique.

Adult↗

Resistance of rapidly expanded random skin flaps to bacterial invasion.

This study tested the hypothesis that rapidly expanded random pattern skin flaps demonstrate enhanced resistance to bacterial invasion from intradermal injection of Staphylococcus aureus in a porcine model. Sites for a 6 X 12 cm expanded, a 6 X 9 cm sham-expanded, and a 6 X 6 cm acute random pattern skin flap were outlined, but not elevated, on the backs of 14 white pigs. A 450-cc tissue expander inserted beneath the panniculus carnosus at the site for expansion was sequentially filled to the limits of skin viability each day for 5 days. At the sham site a tissue expander was similarly inserted but left unexpanded; the acute flap site was left undisturbed. On day 8, flaps were elevated, immediately sutured in place, and 0.1 ml of saline solution containing 10(7) Staphylococcus aureus inoculated intradermally at four corresponding sites in each flap and at three sites in normal skin. In seven animals these sites were at the proximal base of the flaps; in seven others the sites were distal. The resulting areas of erythema and skin ulceration were measured on each of the next 3 days and the measurements compared. At corresponding proximal sites, the mean area of erythema and ulceration measured over the next 3 days in expanded flaps (31.2 mm2) and in sham-expanded flaps (33.8 mm2) was significantly less than in acute flaps and control skin (47.5 mm2, 43.4 mm2, p less than 0.05). Measurements in the rapidly expanded flaps were not significantly different than those in the sham-operated expanded flaps.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

A fasciocutaneous flap for vaginal and perineal reconstruction.

A skin and fascia flap from the medial thigh is proposed for vaginal and perineal reconstruction. Dissection, vascular injection, and radiographs of 20 fresh cadaver limbs uniformly demonstrated the presence of a communicating suprafascial vascular plexus in the medial thigh. Three to four nonaxial vessels were consistently found to enter the proximal plexus from within 5 cm of the perineum. Preservation of these vessels permitted reliable elevation of a 9 X 20 cm fasciocutaneous flap without using the gracilis muscle as a vascular carrier. Fifteen flaps in 13 patients were used for vaginal replacement and coverage of vulvectomy, groin, and ischial defects. Depending on the magnitude of the defect, simultaneous and independent elevation of the gracilis muscle provided additional vascularized coverage as needed. Our experience indicates that the medial thigh fasciocutaneous flap is a durable, less bulky, and potentially sensate alternative to the gracilis musculocutaneous flap for vaginal and perineal reconstruction.

Adult↗

Knee joint salvage utilising a plantar musculocutaneous island pedicle flap.

A young adult male presented with an open tibia-fibula fracture, extensive circumferential soft tissue loss and exposed bone. Although the fracture sites were stabilised by an external fixator, chronic infection complicated this 2-week-old wound. Treatment by amputation was elected. Local skin alone was inadequate for coverage of a preferred below-knee amputation. As an alternative to above-knee amputation, the patient underwent coverage of a below-knee amputation using a musculocutaneous island pedicle flap of sensate plantar skin and muscle.

Adult↗

Comparison of continuous and interrupted suture techniques in microvascular end-to-side anastomosis.

To compare the speed and patency rates of the continuous and interrupted suture techniques in microvascular end-to-side anastomosis, 10 anastomoses utilizing each technique were performed using a femoral artery-superficial epigastric vein bypass model in Sprague-Dawley rats. The continuous suture technique was found to be almost twice as fast as the interrupted technique with no functional compromise. Patency for both techniques was 100 percent. These results are similar to those of several recent reports comparing the two techniques in end-to-end anastomosis and suggest that the continuous suture technique may be the most efficient technique for end-to-side anastomosis as well.

Animals↗

Comparison of the effect of bacterial inoculation in musculocutaneous and fasciocutaneous flaps.

The skin fascial flap is now recognized as a reliable flap for use in reconstructive surgery. The fasciocutaneous flap has been advocated for coverage of chronic infected wounds after debridement as an alternative to the musculocutaneous flap. Previous experimental and clinical studies have demonstrated the superior resistance of the musculocutaneous flap as compared to the random-pattern flap to bacterial inoculation. A canine model is presented for comparison of the effect of bacterial inoculation in fasciocutaneous and musculocutaneous flaps of similar dimensions. The area of skin necrosis secondary to bacterial inoculation was similar in these two flap types despite greater blood flow and skin oxygen in the fasciocutaneous flap. In a study of closed wound spaces formed by the deep surface of these two flap types, a greater degree of inhibition and elimination of bacterial growth and more collagen deposition are observed in the musculocutaneous wound space than in the fasciocutaneous flap.

Animals↗

Management of foot injuries with free-muscle flaps.

Transfer of a free-muscle graft with application of a split-thickness skin graft is one of many techniques available for reconstruction of the massive foot injury. The durability of such a reconstruction has been questioned. We have treated nine patients suffering from foot injuries with extensive soft-tissue loss. Each patient underwent reconstruction using a free-muscle transfer covered by a split-thickness skin graft. A mean follow-up of 33 months (range 17 to 48 months) is reported for these nine patients. Each patient is ambulatory. One patient developed an ulcer on the plantar surface, which was treated successfully by flap revision and skin grafting. We feel this technique provides a durable reconstruction for significant soft-tissue loss of the foot.

Adult↗