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Biomedical subjects

N Weinzweig

Publications and source records attributed to N Weinzweig.

50 records · Page 3Linked to original sources
PubMed1995

Free tissue failure is not an all-or-none phenomenon.

A common misconception among microsurgeons is that free tissue failure is an "all-or-none" phenomenon. In other words, there is an instantaneous cessation of blood flow to a flap primarily due to thrombosis at the arterial or venous anastomotic site (primary thrombosis) with complete flap loss as a result. Contrary to this belief, we have found that free tissue transfers occasionally "die" a slow, progressive, and partial death. This most likely is due to gradual "shutting down" of the microcirculation by the showering of microemboli downstream from the arterial anastomosis (secondary thrombosis). We discuss our clinical experience during the past 6 years with 10 patients in whom free flap failure was not an all-or-none phenomenon and describe the expectant management of these failing free flaps. Microvascular reconstruction of the lower extremities was performed for recalcitrant sickle cell ulceration, chronic venous stasis ulceration in a patient with anti-thrombin III deficiency, dry gangrene of the plantar surface of the foot and toes secondary to posterior tibial artery injection in an intravenous drug abuser, Gustillo type IIIc injury requiring reconstitution of the femoropopliteal artery after an automobile bumper injury, Gustillo type IIIb injury resulting from gunshot wounds, an open ankle joint in a patient with severe peripheral vascular disease, and osteomyelitis. Other cases included cheek soft tissue reconstruction after wide resection of a recurrent dermatofibrosarcoma protuberans of the parotid gland, chest wall coverage after claviculectomy for osteoradionecrosis, and thumb replantation complicated by refractory vasospasm. Latissimus dorsi (four patients), rectus abdominis (three patients), scapular (one patient), and radial forearm fasciocutaneous (one patient) flaps were used. Flap compromise was detected between 4 hours and 6 weeks after surgery. Salvage attempts included Fogarty thrombectomy (four patients), anastomotic revision (two patients), streptokinase instillation (one patient), and leech application (one patient). Failing free flaps were managed expectantly with the use of daily dressing changes. This allowed for the survival of sufficient soft tissue to effect coverage of exposed bone, tendon, or joint. Hyperbaric oxygen was not administered. Tangenital excision of the eschar was performed between 6 and 51 days after free tissue transfer. Skin grafting was delayed for 15 to 80 days. In all cases, a successful outcome was achieved ultimately by either a single skin-grafting procedure (seven patients) or groin flap coverage (one patient). Follow-up ranged from 2 to 35 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Constriction band-induced vascular compromise of the foot: classification and management of the "intermediate" stage of constriction-ring syndrome.

Gangrene of an extremity secondary to a congenital constriction band may result from in utero or postnatal vascular compromise. Often ths process is completed in utero following spontaneous resolution of the vascular insufficiency, resulting in a healed wound by fetal repair and regeneration or in amputation of the distal part. When this process is progressive as a result of worsening lymphaticovenous and/or arterial obstruction with associated soft-tissue necrosis, salvage of the distal part can be accomplished by immediate decompression to evacuate the lymphedema fluid, staged band excision, Z-plasty closure, and topical antimicrobial therapy of the open wound. A revised classification of constriction-ring syndrome incorporating the "intermediate" stage (3B) of severe lymphaticovenous compromise with soft-tissue loss is introduced.

Adult↗
PubMed1995

Lower limb salvage by microvascular free-tissue transfer in patients with homozygous sickle cell disease.

Chronic, excruciatingly painful ulcerations of the lower extremities in patients with homozygous sickle cell anemia (HbSS) present a frustrating clinical problem for the reconstructive surgeon. Despite adequate wound care and skin grafting, there is a dismally high incidence of recurrence. Furthermore, there is a paucity of reliable locoregional fasciocutaneous, muscle, and myocutaneous flaps in the ankle region. Free-tissue transfer has become the procedure of choice for reconstruction of the lower third of the leg. However, in sickle cell anemia, does the obligate period of flap ischemia inherent in free-tissue transfer inevitably doom a flap to failure? We present our multidisciplinary experience over 55 months with five free flaps in four homozygous sickle cell anemia patients 21 to 38 years old who had chronic nonhealing leg ulcerations. Special perioperative measures included exchange transfusion to lower hemoglobin S to below 30 percent, maintaining the hematocrit at 31 to 35 percent, intraoperative flap washout and perfusion with warm heparinized saline-dextran solution, administration of dextran and aspirin intraoperatively and postoperatively, prophylactic topical and systemic anti-Pseudomonas antibiotics, supplemental oxygen, and warm ambient room temperature. Flaps included the latissimus dorsi muscle (two patients), the temporoparietal fascia (one patient), and "split" omentum for bilateral lower limb salvage (one patient). Successful free-tissue transfer was accomplished in all patients. One patient suffered gradual partial occlusion of the microcirculation by sickled erythrocytes following a transient hypothermic, hypotensive episode. Sufficient flap tissue survived to permit skin grafting with an excellent result. Pseudomonas infection occurred in two patients (three flaps).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

A simple fail-safe method for the harvesting of cranial bone.

The technique of cranial bone graft harvesting with the sagittal saw is described. With this technique regular bone grafts of any size can be obtained. Bone-graft size dictates the technique to be used. Small grafts (less than 3.0 cm in shortest dimension) are harvested in situ, while larger grafts are harvested by formal craniectomy.

Bone Transplantation↗
PubMed1994

Oromandibular reconstruction using a keel-shaped modification of the radial forearm osteocutaneous flap.

The keel-shaped modification for harvest of the radial forearm osteocutaneous flap has been used to reconstruct 19 oromandibular defects in 18 patients. Fourteen men and 4 women ranging in age from 22 to 72 years have undergone composite mandibular reconstruction, with follow-up ranging from 3 to 36 months. Sixteen patients (17 reconstructions) had resection of advanced malignancies, and 2 patients sustained shotgun wounds. Twelve symphyseal and 7 lateral or posterior defects were reconstructed with donor radius bone ranging in length from 5 to 13.5 cm. Double osteotomies were performed in 7 patients. Two skin paddles were used in 4 patients to provide simultaneous intraoral lining and external skin coverage. The radial forearm osteocutaneous flap is still an excellent choice for oromandibular reconstruction. Anterior and lateral composite mandibular defects were satisfactorily reconstructed both aesthetically and functionally using the keel-shaped modification of the radial forearm flap. Donor-site problems were uncommon and minor, and long-term forearm function was minimally affected. Radius fracture occurred in only 1 patient.

Adult↗
PubMed1994

Histomorphology of neochondrogenesis after antihelical fold creation: a comparison of three otoplasty techniques in the rabbit.

The purpose of this article is twofold: (1) to investigate the histomorphology of cartilaginous proliferation using three different otoplasty techniques and (2) to determine whether recurrence is related either to the method of otoplasty or the duration of suture fixation. Eighteen 6-week-old New Zealand white rabbits were divided into three equal groups. In each animal, a skin pocket was developed on the posterior surface of both ears; the perichondrium of the left ear was stripped off, whereas the perichondrium of the right ear was left undisturbed. Otoplasties were performed by inserting permanent mattress sutures with (Converse-Wood-Smith) or without (Mustardé) cartilaginous incisions or by scoring of the anterior cartilaginous surface of the antihelix (Stenstrom). In each group, sutures were cut at 1, 2, 4, and 6 weeks and the animals killed 1 week later. Histomorphometric analysis was performed. Perichondrial stripping stimulated cartilaginous proliferation in all groups. The antihelical fold maintained its shape best in group 3, in which the anterior perichondrium was rasped; a fibrocartilaginous cap formed over the rasped convex surface of the antihelical fold, reinforcing and stabilizing the newly created fold. Groups 1 and 2, in contrast, demonstrated significantly less anterior cartilaginous proliferation than did group 3, and cap formation was not observed. No significant differences were apparent between groups 1 and 2 in either the quantity or quality of cartilaginous proliferation in any of the time periods. Cutting the sutures at 1 week resulted in loss of shape or "flattening" of the fold in all groups; however, increased cartilaginous proliferation between 2 and 6 weeks stabilized the fold, minimizing deformability.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Vitamin C reduces ischemia-reperfusion injury in a rat epigastric island skin flap model.

Free radicals have been implicated in the cause of ischemia-reperfusion injury. Various agents have been used in an attempt to reduce ischemia-reperfusion injury pharmacologically, including free radical scavengers. Vitamin C (ascorbic acid), a well-known free radical scavenger, has not, to the best of our knowledge, been evaluated in this respect. Previous work at our institution has shown that vitamin C decreases capillary permeability, thus significantly reducing fluid resuscitation requirements in postburn cases. Because this is due in part to the scavenging effect of vitamin C on free radicals, we investigated the role, if any, of vitamin C on ischemia-reperfusion injury in a rat epigastric island skin flap model. Twenty-four adult Sprague-Dawley rats were divided into control and vitamin C groups. Superficial epigastric island skin flaps measuring 6.0 x 3.5 cm were raised. Pedicles were isolated and occluded with microvascular clamps for 6 hours. The flaps were then sutured back to their beds over Steri-Drape barriers. Fifteen minutes before reperfusion, the control group flaps were perfused via femoral artery cannulation with normal saline (2.5 ml/kg). The vitamin C-treated group was perfused in a similar fashion with 2.5 ml/kg of a vitamin C/normal saline solution (27 mg/ml). The animals were observed for 7 days, and the percentage of flap survival was determined using a paper template technique. The vitamin C-treated group demonstrated a significantly higher percentage of flap survival than did the control group (25.8% mean vs. 7.5% mean, p < 0.025). In this animal model, vitamin C reduced or limited reperfusion injury after 6 hours of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The distally based radial forearm fasciosubcutaneous flap with preservation of the radial artery: an anatomic and clinical approach.

The axial-pattern reverse radial forearm fasciocutaneous flap has become one of the primary flaps for reconstruction of soft-tissue defects of the hand. The two main disadvantages of this flap are (1) sacrifice of a major artery that may possibly jeopardize hand viability and (2) morbidity and appearance of the donor site. In an effort to overcome these drawbacks, an anatomic study of a distally based radial forearm fasciosubcutaneous flap with preservation of the radial artery was conducted. Seventeen fresh cadaver forearms were dissected to investigate the contribution of the distal radial artery and its superficial and deep branches to the fasciosubcutaneous plexus of the forearm. The blood supply to the radial forearm fasciosubcutaneous tissue was found to emanate from 6 to 10 septocutaneous perforators of the distal radial artery in the vicinity of the anatomic snuff box that "fan out" at the level of the deep fascia to form a rich plexus supplying the forearm fascia, subcutaneous tissue, and skin. There appeared to be a definite directional component, with the arterioles running longitudinally along the intermuscular septum. The deep fascia and subcutaneous tissue were found to have their own venous system accompanying the small perforating arterioles. Encouraged by these findings, we proceeded to utilize this fasciosubcutaneous flap for coverage of the thumb-index web space (three patients), the dorsum of the hand (two patients), and both the palmar and dorsal aspects of the hand (one patient). Five flaps had almost complete survival. The largest flap in our series suffered significant loss. Minor skin-graft loss occurred in a few cases, and we now delay skin grafting for several days. The distally based radial forearm fasciosubcutaneous flap with preservation of the radial artery can be a very useful and reliable alternative for repairing soft-tissue defects of the hand, obviating the need for the classic fasciocutaneous flap or even a free flap. This flap not only preserves the radial artery, which is essential in cases where only the radial artery is functioning, such as following severe hand injuries, but also provides a more acceptable donor site.

Adolescent↗
PubMed1994

Lower face reconstruction using a neurosensory osteocutaneous radial forearm flap and Webster modification lip repair.

An innervated bipaddled osteocutaneous radial forearm free flap was combined with a Webster modification lip repair to successfully reconstruct in one stage the lower face following a devastating shotgun injury with loss of the anterior mandible, floor of the mouth, full-thickness chin, and subtotal lower lip. In addition to a pleasing aesthetic appearance with restoration of facial contour, the patient had a sensate flap with intelligible speech and no problems with drooling or mastication. This approach to a most complex reconstructive problem is technically feasible with a satisfactory aesthetic and functional outcome.

Adult↗
PubMed1994

Radial, ulnar, and median nerve palsies caused by a congenital constriction band of the arm: single-stage correction.

Single-stage correction of a congenital constriction band of the arm in an infant with radial, ulnar, and median nerve dysfunction is reported with significant improvement in neurologic function. This was accomplished by thorough preoperative physical examination and neurologic evaluation, circumferential excision of the constricting band, decompression of the involved peripheral nerves, and multiple large Z-plasties for skin closure. Based on the case presented here and a review of the literature, management of patients with congenital constriction rings overlying major nerve trunks should include (1) complete neurologic examination, even in the infant, (2) electromyographic and nerve conduction studies if there is any evidence of nerve dysfunction, (3) early complete excision of the band in one stage if there is no evidence of edema seen with lymphatic or venous obstruction (otherwise, two-stage removal of the band should be planned), and (4) early exploration and decompression of all major peripheral nerves beneath the band if there is any neurologic dysfunction.

Amniotic Band Syndrome↗
PubMed1990

Supplemental vitamin A prevents the tumor-induced defect in wound healing.

To test our hypothesis that supplemental vitamin A would mitigate the impaired healing that occurs in tumor-bearing animals, six groups of C3H mice, eight per group, eating a standard commercial mouse chow ad libitum that supports normal growth, reproduction, and longevity were innoculated with 200,000 C3HBA cells. When tumors measured approximately 6 mm in diameter, the mice were anesthesized and wounded (dorsal skin incisions and subcutaneous polyvinyl alcohol sponges). Twenty-four hours later, two groups (one continued on the chow and the other started on the chow supplemented with 150,000 IU vitamin A/kg chow) underwent local tumor irradiation; two groups, one ingesting the chow, the other the vitamin A supplemented chow, were started on cyclophosphamide therapy; two groups, one ingesting the chow, the other the vitamin A supplemented chow, received neither local tumor irradiation nor cyclophosphamide therapy. An additional two groups ingesting the chow, one group neither innoculated with tumor nor wounded, the other wounded by not innoculated, served as controls. Wound breaking strength and sponge reparative collagen accumulation (assessed by hydroxyproline proline measurement) were used as indicators of wound healing. The mice were killed 12 days after wounding. Tumor presence decreased wound breaking strength and sponge hydroxyproline content; these effects were largely negated by supplemental vitamin A. Local tumor irradiation diminished the adverse effect of tumor on sponge reparative collagen content but to a lesser extent than the supplemental vitamin A. Supplemental vitamin A added to the irradiation effect on healing but irradiation did not add to the vitamin A effect. Cyclophosphamide, a systemic radiomimetic anti-tumor agent, did not alter the impaired wound healing of the tumor-bearing mice. Supplemental vitamin A mitigated the impaired wound healing in the cyclophosphamide-treated tumor-bearing mice. Supplemental vitamin A also moderated the effects of wounding, tumor, and tumor therapies (local irradiation and cyclophosphamide) on the increase in adrenal size, leukopenia, thrombocytopenia, and thymic involution (except the last was not moderated in the cyclophosphamide-treated tumor-bearing rats). The splenic enlargement in the untreated tumor-bearing wounded rats and in those treated with cyclophosphamide was lessened by supplemental vitamin A. We hypothesize that these anti-stress effects of vitamin A underlie, in part, its action in mitigating the impaired wound healing of tumor-bearing mice, including those treated by local irradiation or cyclophosphamide. These findings have implications for the care of patients with malignant tumors.

Animals↗
PubMed1988

The versatile axial pattern digital transposition flap.

The anatomic and clinical basis for a reliable and versatile axial pattern transposition flap for reconstruction of complex distal finger injuries is presented. This is a one-step procedure utilizing the nondominant side digital skin with possible preservation of the nerve to the fingertip. This flap obviates the necessity for a distant donor site and provides nonbulky good quality tissue. In eight patients requiring nine flaps, it has proved valuable in the salvage of severely injured digits. These injuries probably would have required distant flap reconstruction or flaps that might have jeopardized adjacent digits.

Adolescent↗
PubMed1988

Infraclavicular median nerve compression caused by a lipoma.

The most common site of median nerve compression is in the carpal tunnel, the most common of all entrapment neuropathies. Less frequent entrapment neuropathies of the median nerve include the anterior interosseous and pronator syndromes in the proximal forearm. Even less commonly seen is entrapment at the infraclavicular segment of the brachial plexus. Median nerve compression at the level of the axilla has been reported as being caused by anomalous axillary arch muscles, anomalous vascular perforations of the nerve or its roots, the pectoralis minor muscle, and a thickening of the deltopectoral fascia. To the authors' knowledge, this is the first report of compression at that level by a benign tumor.

Clavicle↗