Menachem R. Wexler

Deep partial skin thickness burns: A reproducible animal model to study burn wound healing

A reproducible deep partial skin thickness burn model using guinea-pigs to study the healing process of this injury is described. Round aluminium templates heated to 75 degrees C and applied for 5 s to the moistened, clipped and depilated dorsal skin produced the desired depth of injury. This model is applicable for the study of the three main components of the burn wound healing process: epithelialization, contraction and scar formation. It is recommended that the India ink injection technique be used to confirm the depth of the burn wound.

Purse-string suture for reduction and closure of skin defects

Purse-string subcuticular suture for closure or diminishing skin defects is reported. The same principle applied to breast surgery resulted in a simple and useful way of reducing the size of the areola.

Structural and functional evaluation of modifications in the composite skin graft: cryopreserved dermis and cultured keratinocytes.

Structural and functional aspects of modifications in the composite skin graft consisting of cultured keratinocytes and cryopreserved dermis were determined. Cryopreserved human cadaveric dermis separated from skin by short and mild trypsinization was compared with dermis obtained by prolonged incubation in medium and with fresh dermis obtained by the same methods. All types of dermis were shown to retain normal ultrastructure and topographic organization, as detected by scanning and transmission electron microscope and immunofluorescence analysis. However, in fresh skin, the layers were more firmly attached, mechanical separation was more difficult, and residual epidermis often remained attached to the dermis. Keratinocytes attached better, began replication earlier, and generally reached higher cell numbers when cultured on trypsinized dermis than on medium-treated dermis. The performance of several modifications in the reconstitution and grafting procedures of the composite skin graft after transplantation to athymic mice was examined. Cultured epidermis combined onto trypsinized or medium-treated whole and meshed dermis, dermis pregrafted and allowed to take before transplanting epidermis on top, and keratinocytes grown into multiple epithelia on top of trypsinized meshed or whole dermis prior to grafting. The best grafting results were obtained with an “instant” reconstituted skin model: multiple epithelia grown in vitro combined immediately before grafting onto meshed trypsinized dermis. The transplantation results of this modification were significantly better than those of all the other modifications, including initial growth of keratinocytes into multiple epithelia on top of trypsinized dermis prior to grafting.

The prevention of cardiac arrhythmias produced in an animal model by the topical application of a phenol preparation in common use for face peeling.

We have shown in an animal model that complex ventricular arrhythmias produced by topical application of a phenol preparation that is used in face peeling can be prevented by a brisk diuresis at the time of application or by gradual application of the phenol preparation. We recommend that continuous cardiac monitoring and recording be performed in patients having topical phenol applications in order to determine the true incidence of cardiac arrhythmias and to ascertain if they are prevented by a forced diuresis, by the gradual application of the preparation, or by a combination of both.

Cryopreserved cadaveric allografts for treatment of unexcised partial thickness flame burns: clinical experience with 12 patients

Partial thickness burns (PTB) usually heal within 3 weeks. Prevention of infection and desiccation of the wounds are crucial for optimal healing. Early tangential excision of the burn eschar and allografting prevent deepening of the burns, and are therefore advocated for treatment with the best functional and aesthetic results. For superficial partial thickness burns (SPTB) conservative use of topical antimicrobial agents with frequent dressing changes are implemented. We compared the conservative treatment for PTBs and SPTBs to grafting cryopreserved cadaveric allografts with no prior excision. Twelve patients with flame PTB areas were allografted after mechanical debridement without excision of the burn wounds. The allografts were cadaveric skin cryopreserved by programmed freezing and stored at -180 degrees C for 30-48 months. Matching burns for depth and area were treated with silver sulfadiazine (SSD) one to two times daily until healing or debridement and grafting were required. It was found that 80 per cent of the cryopreserved allografts adhered well and 76 per cent of the treated areas healed within 21 days, whereas only 40 per cent of the SSD-treated burns healed within 21 days. Partial thickness burns can be treated successfully with viable human allografts (cryopreserved cadaveric skin) with no prior surgical excision. The burn wounds heal well within 3 weeks. For deep partial thickness burns (DPTB) treatment with allografts has no advantage if they have not been previously excised.

A simplified testing system to evaluate performance after transplantation of human skin preserved in glycerol or in liquid nitrogen.

We have designed and tested a mouse recipient model for evaluation and direct comparison of skin-preservation procedures. Glycerolized skin was compared with cryopreserved and fresh cadaveric skin. Human skin samples were grafted on Balb/c mice, and primary take was evaluated after 4 and 7 days. The results demonstrate that although all grafted specimens were initially accepted as indicated by gross observations, histologic differences were evident and significant. Cryopreserved skin grafts performed better than did glycerolized skin even after a transplantation period as short as 4 days; this difference became even more pronounced after 7 days. Both methods of preservation provided a less successful product than did fresh viable cadaveric skin. However, for very short periods of grafting the performance of glycerolized skin might be considered adequate (79% compared with cryopreserved). Because the present study used an immunocompetent xenogeneic model, it is possible that the period of adequate allogeneic grafting will be prolonged in patients who are immunosuppressed. The present model is simple to use, requires a minimum of maintenance and expertise, and has inherent clinical relevance, because it is concerned primarily with the clinical performance of the skin. Thus it may be used as a quality control test for banked skin.

The correction of seventh nerve palsy lagophthalmos with gold lid load (16 years experience)

Seventy-one patients with facial palsy following implantation of a gold prosthesis into the upper eyelid are reviewed; the average follow-up is 3.2 years. Eighty percent (57) of the patients demonstrated no complications and had satisfactory results. The methods, complications, advantages, and disadvantages are discussed.

Hemangioma of the median nerve

Intrinsic hemangiomas of peripheral nerves are extremely rare. Eight cases have been reported in the literature and only two of them involved the median nerve. An extensive cavernous hemangioma with carpal tunnel symptomatology is reported.

Mandibular resorption from silicone chin implants in children

Silicone implants were placed in the nasal, cheek, and chin areas in children with Downs syndrome to improve facial appearance. Clinical and radiologic follow-up evaluation revealed significant crater-like bone resorption in the mandibular symphysis in 75% of the cases. All of these implants were removed, and the bone showed regrowth to the presurgical state. No sign of bone damage was present in the malar or nasal areas.

Efficacy of the topical anesthetic cream, EMLA, in alleviating both needle insertion and injection pain

To assess the efficacy of the topical anesthetic cream, EMLA, in alleviating the pain produced by infiltration of local anesthetic prior to surgical skin biopsies, a randomized, double-blind, placebo-controlled study was performed on 54 patients undergoing 162 excisional biopsies. Both pain induced by needle insertion and pain induced by local injection were significantly diminished after topical application of EMLA cream. However, part of the effect was placebo, because the placebo ointment (Vaseline) also produced significant pain alleviation.