Jan Vranckx

Updated Scar Management Practical Guidelines: Non-invasive and invasive measures

Hypertrophic scars and keloids can be aesthetically displeasing and lead to severe psychosocial impairment. Many invasive and non-invasive options are available for the plastic (and any other) surgeon both to prevent and to treat abnormal scar formation. Recently, an updated set of practical evidence-based guidelines for the management of hypertrophic scars and keloids was developed by an international group of 24 experts from a wide range of specialities. An initial set of strategies to minimize the risk of scar formation is applicable to all types of scars and is indicated before, during and immediately after surgery. In addition to optimal surgical management, this includes measures to reduce skin tension, and to provide taping, hydration and ultraviolet (UV) protection of the early scar tissue. Silicone sheeting or gel is universally considered as the first-line prophylactic and treatment option for hypertrophic scars and keloids. The efficacy and safety of this gold-standard, non-invasive therapy has been demonstrated in many clinical studies. Other (more specialized) scar treatment options are available for high-risk patients and/or scars. Pressure garments may be indicated for more widespread scarring, especially after burns. At a later stage, more invasive or surgical procedures may be necessary for the correction of permanent unaesthetic scars and can be combined with adjuvant measures to achieve optimal outcomes. The choice of scar management measures for a particular patient should be based on the newly updated evidence-based recommendations taking individual patient and wound characteristics into consideration.

Perforator topography of the deep inferior epigastric perforator flap in 100 cases of breast reconstruction

&NA; The anatomic topography of the perforators within the rectus muscle and the anterior fascia largely determines the time needed to harvest the perforator free flap and the difficulty of the procedure. In 100 consecutive cases, the topographic patterns of the perforators were investigated. In 65 percent, a short intramuscular course was seen. In 16 percent, a perforator at the tendinous intersection was encountered. In 9 percent, the largest perforator was found to have a long intramuscular course. In 5 percent, a subfascial course was found, and in another 5 percent, a paramedian course was found. In 74 percent of flaps, just one perforator was used, whereas two perforators were dissected in 20 percent. Only in 6 percent of flaps were three perforators used. A long intramuscular course (>4 cm) lengthens the dissection substantially, especially when the intramuscular course is in a step‐wise pattern. The subfascial course requires precarious attention at the early stage of the perforator dissection when splitting the fascia. The perforators at the tendinous intersections are the most accessible and require a short but intense dissection in the fibrotic tissue of intersection. A paramedian perforator, medial to the rectus muscle, is a septocutaneous rather than a musculocutaneous perforator. The straightforward dissection almost extends up to the midline. Therefore, dissection always is performed at one side and, if no good perforators are present, continued at the intact contralateral side. The size of these perforators and their location in the flap determine the choice. One perforator with significant flow can perfuse the whole flap. If in doubt, two perforators can be harvested, especially if they show a linear anatomy so that muscle fibers can be split. The only interference with the muscle exists in splitting the muscle fibers. A perforator that lies in the middle of the flap is preferable. For a large flap, a perforator of the medial row provides better perfusion to zone 4 than one of the lateral row because of the extra choke vessel for the lateral row perforators. The clinical appearance of the perforators is the key element in the dissection of the perforator flap. Perforator topography determines the overall length and difficulty of the procedure. (Plast. Reconstr. Surg. 109: 1912, 2002.)

Integration of Blood Outgrowth Endothelial Cells in Dermal Fibroblast Sheets Promotes Full Thickness Wound Healing

Vascularization is the cornerstone of wound healing. We introduced human blood outgrowth endothelial cells (hBOEC) in a self‐assembled human dermal fibroblast sheet (hDFS), intended as a tissue‐engineered dermal substitute with inherent vascular potential. hBOEC were functionally and molecularly different from early endothelial progenitor cells and human umbilical vein endothelial cells (HUVEC). hBOEC alone, unlike HUVEC, efficiently revascularized and re‐oxygenated the wound bed, both by active incorporation into new vessels and by trophic stimulation of host angiogenesis in a dose‐dependent manner. Furthermore, hBOEC alone, but not HUVEC, accelerated epithelial coverage and matrix organization of the wound bed. In addition, integration of hBOEC in hDFS not only further improved vascularization, epithelial coverage and matrix organization but also prevented excessive wound contraction. In vitro analyses with hBOEC, fibroblasts and keratinocytes revealed that these effects were both due to growth factor crosstalk and to short cutting hypoxia. Among multiple growth factors secreted by hBOEC, placental growth factor mediated at least in part the beneficial effects on keratinocyte migration and proliferation. Overall, this combined tissue engineering approach paves the way for clinical development of a fully autologous vascularized dermal substitute for patients with large skin defects that do not heal properly. STEM CELLS 2010;28:1165–1177

Wet wound healing.

Wound treatment in a flexible transparent chamber attached to the perimeter of the wound and containing a liquid has been extensively tested in preclinical experiments in pigs and found to offer several advantages. It protects the wound; the liquid medium or saline in the chamber provides in vivo tissue culture-like conditions; and antibiotics, analgesics, and various molecules can be delivered to the wound through the chamber. The wound chamber causes no injury to the wound itself or to the surrounding intact skin. Topical delivery of, for instance, antibiotics can provide very high concentrations at the wound site and with a favorable direction of the concentration gradient. A series of 28 wounds in 20 patients were treated with a wound chamber containing saline and antibiotics. Most patients had significant comorbidity and had not responded to conservative or surgical management with débridement and delayed primary closure or skin grafts. Six wounds had foreign bodies present; four of these were joint prostheses. Seven patients were on corticosteroids for rheumatoid arthritis, lupus, or chronic obstructive pulmonary disease, and four patients had diabetes. Most patients were treated with the wound chamber in preparation for a delayed skin graft or flap procedure, but one was treated with a wound chamber until the wound healed. Twenty-five of the wounds (89 percent) healed, and five wounds (18 percent) required additional conservative management after the initial chamber treatment and grafting procedure. Of the three wounds that did not heal, one healed after additional chamber treatment, one had a skin graft that did not take, and one required reamputation at a higher level. Antibiotic delivery was less than one intravenous dose daily, which avoided the potential for systemic absorption to toxic levels. Antibiotics such as vancomycin and gentamicin could be used in concentrations of up to 10,000 times the minimal inhibitory concentration. Forty-eight hours after application, 20 percent or more of the original antibiotic concentration was present in the wound chamber fluid. In conclusion, the wound chamber provides a safe, powerful tool in the treatment of difficult infected wounds.

In vivo gene delivery of Ad-VEGF121 to full-thickness wounds in aged pigs results in high levels of VEGF expression but not in accelerated healing

We have previously reported that endogenous vascular endothelial growth factor (VEGF) concentration in older pig wounds peaked later and at one‐fourth the level of young pigs. These data suggested that VEGF might play a major role in the healing of full‐thickness wounds in the aged pig. By in vivo gene transfer using the microseeding technique, we treated full‐thickness wounds with different doses of VEGF‐expressing adenoviral vector (Ad‐VEGF) varying from 1 × 107 to 2.7 × 1011 particles per wound (ppw). We found that the VEGF expression in wound fluid followed a dose–response pattern. However, when wounds were microseeded with the highest concentration of Ad‐VEGF (2.7 × 1011 ppw), diminished healing rates were found. We then determined the minimal functional concentrations of Ad‐VEGF. We used five aged Yucatan minipigs, all retired breeders, to analyze the role of over‐expression of 1 × 108 and 1 × 109 ppw of Ad‐VEGF (n= 78) in terms of healing of full‐thickness wounds, all 2.5 × 2.5 × 1 cm in size (n= 158). The Ad‐VEGF solutions were delivered to the wound floor and borders by in vivo microseeding. Control wounds (n= 80) were microseeded with Ad‐Lac‐Z (n= 25), treated with saline (n= 49) or treated dry (n= 6). All wounds except for the dry‐treated ones were covered with a wound chamber and a wet environment was created by injecting 2.5 ml saline into the chamber. Peak VEGF expression (2300–4000 pg/ml) was detected on days 2 or 3 post gene delivery. This level of VEGF expression was not seen in the saline (n= 49) or Ad‐null (n= 25) control groups. The VEGF expression in wounds treated with 1 × 108 and 3 × 108 ppw (n= 39) exhibited a slower onset with a peak concentration of 400–920 pg/ml on days 5–7. Although high levels of VEGF expression were achieved in the local wound environment, we could not show a significant increase in neovascularization as compared to saline‐treated wounds. No significant differences were observed in the rate of reepithelialization and wound contraction among groups of full‐thickness wounds treated with Ad‐VEGF, Ad‐null mutant, or saline in the aged “wet wound healing” pig model. These results indicate that increased levels of VEGF in wounds produced by in vivo gene transfer have little effect on the healing of full‐thickness wounds in the aged pig model. Moreover, significantly higher levels of VEGF expression by Ad‐VEGF could lead to impaired wound healing.

Learning Curve in Tracheal Allotransplantation

The first vascularized tracheal allotransplantation was performed in 2008. Immunosuppression was stopped after forearm implantation and grafting of the recipient mucosa to the internal site of the transplant. Nine months after forearm implantation, the allograft was transplanted to the tracheal defect on the radial blood vessels. Since then, four additional patients have undergone tracheal allotransplantation, three (patients 2–4) for long‐segment stenosis and one (patient 5) for a low‐grade chondrosarcoma. Our goal was to reduce the time between forearm implantation and orthotopic transplantation and to determine a protocol for safe withdrawal of immunosuppressive therapy. Following forearm implantation, all transplants became fully revascularized over 2 months. Withdrawal of immunosuppression began 4 months after graft implantation and was completed within 6 weeks in cases 2–4. Repopulation of the mucosal lining by recipient cells, to compensate for the necrosis of the donor mucosa, was not complete. This resulted in partial loss of the allotransplant in patients 2–4. In patient 5, additional measures promoting recipient cell repopulation were made. The trachea may be used as a composite tissue allotransplant after heterotopic revascularization in the forearm. Measures to maximize recipient cell repopulation may be important in maintaining the viability of the transplant after cessation of immunosuppression.

Cell suspension cultures of allogenic keratinocytes are efficient carriers for ex vivo gene transfer and accelerate the healing of full-thickness skin wounds by overexpression of human epidermal growth factor

The concept of using growth factor therapy to induce wound repair has been endorsed in studies that show reduced growth factors in wound fluid from chronic and aged wounds. In this study, we used cell suspensions of allogenic keratinocytes as gene‐delivery vehicles for human epidermal growth factor (hEGF) and analyzed their impact on wound repair in a porcine wound‐healing model. Full‐thickness wounds were created on the backs of six Yorkshire pigs and covered with a wound chamber to create a wet wound‐healing environment. First, 5 × 105 allogenic, autogenic, or mixed keratinocytes were transplanted into wounds and healing parameters were analyzed. Second, we measured long‐term reepithelialization and contraction rates from day 8 until day 35. In the third experiment, allogenic keratinocytes were transfected with an hEGF‐expressing plasmid pCEP‐hEGF and transplanted in full‐thickness wounds to improve repair. Wounds treated with autogenic, allogenic, or mixed keratinocytes showed a significantly higher rate of reepithelialization relative to saline‐treated control wounds. Repetitive biopsies indicated that the use of allogenic keratinocytes did not lead to long‐term wound breakdown. Wounds treated with hEGF‐expressing allogenic keratinocytes reepithelialized faster than wounds treated with allogenic keratinocytes or control wounds. With a peak hEGF expression of 920.8 pg/mL, hEGF was detectable until day 5 after transplantation compared with minimal hEGF expression in control wounds. This study shows that allogenic keratinocytes can serve as efficient gene transfer vehicles for ex vivo growth factor delivery to full‐thickness wounds and overexpression of hEGF further improves reepithelialization rates.

Organ Preservation Surgery for Advanced Unilateral Glottic and Subglottic Cancer

Objectives: Functional surgery of unilateral T2b to T3 glottic cancer and cricoid chondrosarcoma is possible using the technique of tracheal autotransplantation. The objective of this paper is to report the functional and oncologic outcome of 24 consecutive patients treated with this technique between 2001 and 2007.

Regulable vascular endothelial growth factor165 overexpression by ex vivo expanded keratinocyte cultures promotes matrix formation, angiogenesis, and healing in porcine full-thickness wounds.

The intricate wound repair process involves the interplay of numerous cells and proteins. Using a porcine full-thickness wound (FTW) healing model, we hypothesized that the ex vivo gene transfer of vascular endothelial growth factor (VEGF)-transfected basal keratinocyte (KC) cell suspensions may generate cross-talk and induce matrix formation, angiogenesis, and accelerated healing. Moreover, to regulate overexpression of isoform 165 of VEGF and its effect on healing, we introduced a tetracycline (TC)-inducible gene switch in the expression plasmid. Autologous basal KCs were cultivated from the porcine donor and transfected using cationic liposomes. A dose-response curve was established to determine optimal activation of the gene switch by TC. In vivo, FTWs were treated with VEGF-transfected KCs and controls. Wound fluids were collected daily and examined using enzyme-linked immunosorbent assay. Biopsies were evaluated using hematoxylin and eosin and immunostaining for fibronectin, CD144, and lectin BS-1. In vitro, highest regulable VEGF165-expression was obtained with 1 microg/mL of TCs. In vivo, after induction of the gene switch by adding 1 microg/mL of TCs to the FTW, we obtained upregulated VEGF165 levels and enhanced fibronectin deposition and found more endothelial cell tubular formations and higher rates of reepithelialization than in controls. This ex vivo gene transfer model may serve as a platform for vascular induction in full-thickness tissue repair.

Tracheal Allograft after Withdrawal of Immunosuppressive Therapy

This letter describes findings from an evaluation of a tracheal allotransplant at 2 years, documented with imaging studies and a video. Despite immunologic rejection of the donor mucosal lining, the tracheal cartilage appears to remain intact without immunosuppression.