Development of new reconstructive techniques: use of Integra in combination with fibrin glue and negative-pressure therapy for reconstruction of acute and chronic wounds

Large wounds resulting from severe injuries are generally treated with extended reconstructive operations (e.g., free flaps), which are accompanied by long hospitalizations and risks of infection, thrombosis, and flap loss. Integra is a collagen template that can be used for reconstruction of defects. The take rate and the rate of infection are essential for the successful use of Integra (Johnson and Johnson, Hamburg, Germany). Whether the take rate and integration of Integra could be improved with the use of fibrin glue and negative-pressure therapy was assessed. Between January of 2002 and December of 2002, patients with large defects who underwent Integra grafting for reconstruction were randomly divided into groups receiving either a new treatment with fibrin glue-anchored Integra and postoperative negative-pressure therapy or conventional treatment. Demographic features, cause of the wound, location of the wound, take rate, complications of Integra coverage, time from Integra coverage to skin transplantation, and functional and aesthetic results were assessed. Twelve patients (with similar group distributions with respect to sex, age, and location and cause of the injury) were included in the study. The take rate was 78 +/- 8 percent in the conventional treatment group and 98 +/- 2 percent in the fibrin/negative-pressure therapy group (p < 0.003). The mean period from Integra coverage to skin transplantation was 24 +/- 3 days in the conventional treatment group but only 10 +/- 1 days in the fibrin/negative-pressure therapy group (p < 0.002). The decrease in the interval between coverage with Integra and skin transplantation resulted in shorter hospital stays. The use of fibrin glue and negative-pressure therapy in combination with Integra could shorten the period from coverage to integration, which would be beneficial in terms of decreased risks of infection, thrombosis, and catabolism. Therefore, it is suggested that Integra be used in combination with fibrin glue and negative-pressure therapy to improve clinical outcomes and shorten hospital stays, with decreased risks of accompanying complications.     

Comparative Experimental Study of Wound Healing in Mice: Pelnac versus Integra

Strategies for skin regeneration have been developed to provide effective treatment for cutaneous wounds and disease. Dermal substitutes have been used to cover the lesion to facilitate cell colonization, thereby promoting dermal regeneration. However, very little is known about Pelnac matrix especially at histological level. Therefore, the present work carried out an experimental in vivo comparative analysis between Pelnac and Integra, the most used dermal templates, in a mouse model of full-thickness skin wounds. Histological sections performed at the 3^rd, 6^th and 9^th days after surgery were analyzed with regard to inflammatory response and vascularization. Both templates were completely incorporated in all animals at the end of the analyzed period. Pelnac-treated animals displayed reduced granulation tissue during the first 6 days of treatment compared to the animals treated with Integra at the same time period. The number of inflammatory cells (neutrophils) was similar in both groups during the period, significantly reducing at the end of inflammatory phase (9^th day of treatment) consistent with the progression of healing process. In addition, the density of blood vessels was also statistically similar in both matrices. Therefore, the two dermal templates displayed comparable biological behavior in tissue repair. It is noteworthy that this is the first experimental study comparing Pelnac and Integra dermal templates with focus on full-thickness skin wounds.     

Reconstructive surgery with a dermal regeneration template: clinical and histologic study.

Integra artificial skin was introduced in 1981 and its use in acute surgical management of burns is well established, but Integra has also been used in patients undergoing reconstructive surgery. Over a period of 25 months, the authors used Integra to cover 30 anatomic sites in 20 consecutive patients requiring reconstructive surgery and then analyzed the clinical and histologic outcomes. The most common reason for surgery was release of contracture followed by resurfacing of tight or painful scars. The authors assessed patients' satisfaction using a visual analog scale and scar appearance using a modified Vancouver Burn Index Scale. They evaluated the progress of wound healing by examining weekly punch-biopsy specimens with standard and immunohistochemical stains. Patients reported a 72 percent increase in range of movement, a 62 percent improvement in softness, and a 59 percent improvement in appearance compared with their preoperative states. Pruritus and dryness were the main complaints, and neither was improved much. Four distinct phases of dermal regeneration could be demonstrated histologically: imbibition, fibroblast migration, neovascularization, and remodeling and maturation. Full vascularization of the neodermis occurred at 4 weeks. The color of the wound reflected the state of neodermal vascularization. No adnexa, nerve endings, or elastic fibers were seen in any of the specimens. The new collagen was histologically indistinguishable from normal dermal collagen. The authors conclude that Integra is a useful tool in reconstructive surgery. The additional cost of its use can be justified by its distinct benefits compared with current methodology.     

The use of vacuum-assisted closure therapy for the treatment of lower-extremity wounds with exposed bone

Lower-extremity wounds with exposed tendon, bone, or orthopedic hardware present a difficult treatment challenge. In this series of patients, subatmospheric pressure therapy was applied to such lower-extremity wounds. Seventy-five patients with lower-extremity wounds, most of which were the result of trauma, were selected for this study. Dressings made of sterile open-cell foam with embedded fenestrated tubing were contoured to the wound size and placed into the wound. The site was covered with an adhesive plastic sheet. The sheet was placed beneath any external fixation devices, or the fixation device was enclosed within the sheet. The tubing was connected to the vacuum-assisted closure pump. Continuous subatmospheric suction pressure (125 mmHg) was applied to the wound site. The wounds were inspected and the dressings were changed every 48 hours.Vacuum-assisted closure therapy greatly reduced the amount of tissue edema, diminishing the circumference of the extremity and thus decreasing the surface area of the wound. Profuse granulation tissue formed rapidly, covering bone and hardware. The wounds were closed primarily and covered with split-thickness skin grafts, or a regional flap was rotated into the granulating bed to fill the defect. Successful coverage was obtained without complication in 71 of 75 patients. Wounds have been stable from 6 months up to 6 years.     

A prospective, blinded, randomized, controlled clinical trial of topical negative pressure use in skin grafting

Topical negative pressure has been demonstrated to improve graft take in a number of noncomparative studies. This study aimed to assess whether split-thickness skin graft take is improved qualitatively or quantitatively with topical negative pressure therapy compared with standard bolster dressings. A blinded, prospective, randomized trial was conducted of 22 adult inpatients of Liverpool Hospital between July of 2001 and July of 2002 who had wounds requiring skin grafting. After grafting, each wound half was randomized to receive either a standard bolster dressing or a topical negative pressure dressing. Skin graft assessment was performed at 2 weeks by a single observer blinded to the randomization. Two patients were lost to follow-up and were excluded from the study. There were 20 patients (12 men and eightwomen) in the study group. The median patient age was 64 years (range, 27 to 88 years), and the mean wound size was 128 cm2 (range, 35 to 450 cm2). The wound exposed subcutaneous fat in eight patients, muscle in six patients, paratenon in four patients, and deep fascia in two patients. At 2 weeks, wounds that received a topical negative pressure dressing had a greater degree of epithelialization in six cases (30 percent), the same degree of epithelialization in nine cases (45 percent), and less epithelialization in five cases (25 percent) compared with their respective control wounds. Graft quality following topical negative pressure therapy was subjectively determined to be better in 10 cases (50 percent), equivalent in seven cases (35 percent), and worse in three cases (15 percent). Although the quantitative graft take was not significant, the qualitative graft take was found to be significantly better with the use of topical negative pressure therapy (p < 0.05). Topical negative pressure significantly improved the qualitative appearance of split-thickness skin grafts as compared with standard bolster dressings.     

Accelerated healing of full-thickness skin wounds in a wet environment

Full-thickness skin wounds are preferably allowed to heal under controlled hydration dressings such as hydrocolloids. It was hypothesized that a wet (liquid) environment rather than a dry or moist one would accelerate the wound healing process. We compared skin repair by secondary intention in full-thickness skin wounds in wet (saline), moist (hydrocolloid), and dry (gauze) conditions in an established porcine wound healing model. The study included three animals with a total of 70 wounds layered in a standardized fashion on the back of young Yorkshire pigs. Twelve days after wounding, 0 percent of dry, 20 percent of moist, and 86 percent of saline-treated wounds were completely reepithelialized (p values = 0.0046 and 0.027 for saline wounds compared with dry and moist wounds, respectively). The accelerated healing was caused at least in part by faster contraction in wet wounds (p value < 0.005 compared with that of other groups 9 and 12 days after wounding). Development of granulation tissue was faster in moist conditions than it was for dry and wet wounds. The thickness and number of cell layers of the newly formed epidermis were greater in dry and wet wounds than in moist ones. It was concluded that these full-thickness porcine skin wounds healed faster in a wet environment than in a moist one. Dry wounds healed more slowly than moist wounds. The basic mechanisms of skin wound repair were influenced by the treatment modality as demonstrated by the observed differences in granulation tissue formation, reepithelialization, and rate of wound contraction.     

The relative roles of aggressive wound care versus revascularization in salvage of the threatened lower extremity in the renal failure diabetic patient

Current literature indicates poor survival and limb salvage rates in renal failure diabetic patients who present with ulcerated or gangrenous lower extremities. Even in those limbs that were successfully revascularized, the amputation rate was as high as 37 percent. This has led some to advocate immediate amputation when treating the threatened limb of a renal failure diabetic patient. The authors reviewed all renal failure diabetic patients in their wound registry to determine whether such pessimism was warranted. The authors then analyzed the relative roles of revascularization and aggressive wound care on long-term limb salvage. Forty-five consecutive renal failure diabetic patients with 71 wounds in 54 limbs were identified. Twenty-seven patients had chronic renal insufficiency, 15 patients had end-stage renal disease, and three patients received kidney transplants. The revascularization procedures (46 percent of all limbs) included angioplasty, femoral-popliteal, femoral-distal, and popliteal-distal bypasses. Forty-three amputations in combination with 67 soft-tissue repairs (delayed primary wound closure, skin grafts, local flaps, pedicled flaps, and free flaps) were necessary to close the defects. After a mean follow-up of over 3 years, the data indicate that 79 percent of wounds healed, 89 percent of all limbs were salvaged, and 49 percent of patients survived. Revascularization improved the threatened limb's salvage rate from negligible to a level similar to that of the adequately vascularized limb. Fifteen out of 71 wounds did not heal because of the patient's early postoperative death, ischemia not amenable to revascularization, or noncompliance. Six below-knee amputations were performed (one despite a patent bypass and five in adequately vascularized patients). The average time for wounds to heal in the revascularized patients was 79 days versus 71 days in adequately vascularized patients. There was an overall 43 percent complication rate. Of the patients who were alive after the 3-year follow-up, 73 percent were independently ambulating, whereas 27 percent were bound to wheelchair or bed. Eighty-two percent of patients were very satisfied with the salvage attempt, 18 percent were moderately satisfied, and all patients said they would go through the process again. The authors believe that salvaging the threatened extremity in the renal failure diabetic patient is justified whether or not the limb requires revascularization. Revascularization improved the limb salvage rate, patient survival, and days for wounds to heal to a level comparable to that of the adequately vascularized limb. The key to subsequently achieving high salvage rates is the quality of perioperative wound care (e.g., serial debridements, antibiotics, dressings) and the timing and selection of appropriate soft-tissue coverage.     

Mesenchymal stromal cells from dermal and adipose tissues induce macrophage polarization to a pro-repair phenotype and improve skin wound healing

The process of wound healing restores skin homeostasis but not full functionality; thus, novel therapeutic strategies are needed to accelerate wound closure and improve the quality of healing. In this context, tissue engineering and cellular therapies are promising approaches. Although sharing essential characteristics, mesenchymal stromal cells (MSCs) isolated from different tissues might have distinct properties. Therefore, the aim of this study was to comparatively investigate, by a mouse model in vivo assay, the potential use of dermal-derived MSCs (DSCs) and adipose tissue–derived MSCs (ASCs) in improving skin wound healing. Human DSCs and ASCs were delivered to full-thickness mouse wounds by a collagen-based scaffold (Integra Matrix). We found that the association of both DSCs and ASCs with the Integra accelerated wound closure in mice compared with the biomaterial only (control). Both types of MSCs stimulated angiogenesis and extracellular matrix remodeling, leading to better quality scars. However, the DSCs showed smaller scar size,superior extracellular matrix deposition, and greater number of cutaneous appendages. Besides, DSCs and ASCs reduced inflammation by induction of macrophage polarization from a pro-inflammatory (M1) to a pro-repair (M2) phenotype. In conclusion, both DSCs and ASCs were able to accelerate the healing of mice skin wounds and promote repair with scars of better quality and more similar to healthy skin than the empty scaffold. DSCs associated with Integra induced superior overall results than the Integra alone, whereas scaffolds with ASCs showed an intermediate effect, often not significantly better than the empty biomaterial.     

Use of dermal regeneration template in contracture release procedures: a multicenter evaluation

Integra dermal regeneration template (Integra Life Sciences, Plainsboro, N.J.) is an effective treatment for full-thickness burns. It can also be useful in contracture release procedures; however, the clinical utility of a dermal regeneration template in contracture release procedures has not been adequately characterized. In this multicenter investigation, the outcomes of release procedures incorporating a dermal regeneration template for 89 consecutive patients, who underwent a total of 127 contracture releases, were retrospectively evaluated. The procedures involved the application of Integra, which includes a temporary silicone epidermal substitute and an artificial dermal layer. After formation of a neodermis, the silicone layer is removed and replaced with an epidermal autograft. Data on patient and contracture site history, treatment methods, physician assessments of range of motion or function, patient satisfaction, recurrence, and adverse events were collected with a standardized questionnaire. Release procedures for the study patients involved the neck, axilla, trunk, elbow, knee, hand, and other anatomical sites. The mean postoperative follow-up period was 11.4 months. At 76 percent of the release sites, range of motion or function was rated as good (significant improvement in range of motion or function) or excellent (maximal range of motion or function possible) by physicians. Responding patients expressed satisfaction with the overall results of treatment at 82 percent of the sites. No recurrence of contracture at 75 percent of the sites was observed during follow-up monitoring. Patient age and prior surgical treatment at the site did not significantly affect the results of treatment. However, outcomes were superior at mature sites, i.e., those for which more than 12 months had elapsed since the original injury. Postoperative complications rarely necessitated regrafting. These results indicate that a dermal regeneration template provides a useful alternative technique for contracture release procedures. The study data indicate that this approach leads to favorable functional outcomes and a high rate of patient satisfaction. This modality also seems to be versatile, because a range of anatomical sites are amenable to treatment with a dermal regeneration template, regardless of prior surgical treatment, and both pediatric and adult patients respond well to this form of therapy. Furthermore, Integra confers functional and cosmetic benefits similar to those of full-thickness grafts but without comparable potential for donor-site morbidity.     

Management of complex groin wounds: preferred use of the rectus femoris muscle flap

This study reviews our experience with the rectus femoris muscle flap for complex groin wound reconstruction. Over the past 5 years, the rectus femoris has become our routine method of groin wound reconstruction. The rectus femoris is harvested through a midanterior incision extending over the distal two-thirds of the thigh. The muscle is elevated on its pedicle and transposed into the groin wound defect either directly or through an intervening skin bridge. Hospital and outpatient records were reviewed for all patients undergoing groin wound reconstruction with this technique from 1999 through 2003. Thirty-seven rectus femoris muscle flaps were performed in 33 patients. The mean patient age was 65.3 years (range, 25 to 88 years). Thirty groin wounds (81.1 percent) occurred after infrainguinal revascularization, 23 (76.7 percent) of which contained prosthetic material. Five (21.7 percent) of these wounds had their prosthetic material removed at the time of reconstruction. The remaining seven groin wounds (18.9 percent) occurred after femoral vessel cannulation for either cardiac or transplant surgery. There were no intraoperative mortalities and no anastomotic hemorrhages. There were no flap losses. Thirty-five of the 37 treated wounds healed (94.6 percent), 26 primarily (70.3 percent) and nine (24.3 percent) after delayed healing and contracture. Reoperation was performed in one patient for flap readvancement and in three patients for prosthetic graft removal after initial flap reconstruction. Two patients (6.1 percent) died during their hospitalization with persistent open groin wounds after flap reconstruction. All muscle flap donor incisions healed, with only two (5.4 percent) experiencing minimal delayed healing. There were no donor-site wound infections and no donor sites required reoperation. Thirty-three groin wounds (89.2 percent) demonstrated culture-positive microbial infection, 15 (45.5 percent) of which were polymicrobial. The 30-day mortality rate was 15.2 percent and the 6-month mortality rate increased to 27.2 percent, with multisystem organ failure as the most common cause. The rectus femoris muscle flap is an effective and reliable means of complex groin wound reconstruction. The muscle flap is dependable and the donor site is not problematic, even in the presence of peripheral vascular disease. On the basis of our clinical results, we believe that the rectus femoris muscle flap is the flap of choice for groin wound reconstruction.     

Stimulated healing of recalcitrant wounds by topical application of enriched cell culture medium: a clinical report.

This study was designed to test the efficacy of enriched cell culture medium as a wound dressing. The rationale was to create within the wound space an optimal microenvironment, conducive to cellular proliferation, vascular granulation tissue formation, and epithelialization. This study was performed on various wounds that failed to respond to previous conventional treatments.A total of 288 wounds were within the inclusion criteria, with only contaminated and neoplastic wounds excluded. Most of the patients (80 percent) were ambulatory, and the wounds were examined by the attending physician once every 7 to 14 days at an outpatient clinic. The remaining 20 percent of patients were admitted to the study while hospitalized.Cell culture medium MCDB, supplemented with insulin, thyroxin, and growth hormone, was gelled. The gel was self-applied once a day to freshly washed wounds, covered with a gauze pad, and anchored with netting.Healing started 7 to 14 days after the initiation of treatment with enriched cell culture medium. However, the criterion for success of the treatment was determined on complete wound closure, which was achieved in 189 of 288 wounds (65.6 percent). Wound closure was correlated with the initial wound volume, stage, and origin. The average time required for closure of wounds caused by systemic pathologies (n = 181) and those based on regional status (n = 107) were 12.0 and 4.4 weeks, respectively, compared with 290 and 10.3 weeks of the previous conventional treatment. In 19 extensive wounds, when vascularized granulation tissue was established, a successful surgical closure was attained.Most wounds of patients who did not continue the enriched cell culture medium treatment (34.4 percent) manifested reduced wound volume, ranging from 11 to 98 percent of initial volume. Discontinuation of treatment was associated with difficulties in reaching the clinic for the weekly examination, rather than for reasons directly related to the treatment itself, and occurred significantly earlier during the treatment period.Thus, enriched cell culture medium was effective in stimulating wound healing in recalcitrant wounds. The healing was rapid with minimum scarring and pain. No side effects or allergic reactions were reported or observed.     

The role of intrinsic muscle flaps of the foot for bone coverage in foot and ankle defects in diabetic and nondiabetic patients

Local muscle flaps, pioneered by Ger in the late 1960s, were extensively used for foot and ankle reconstruction until the late 1970s when, with the evolution of microsurgery, microsurgical free flaps became the reconstructive method of choice. To assess whether the current underuse of local muscle flaps in foot and ankle surgery is justified, the authors identified from the Georgetown Limb Salvage Registry all patients who underwent foot and ankle reconstruction with local muscle flaps and microsurgical free flaps from 1990 through 1998. By protocol, flap coverage was the reconstructive choice for defects with exposed tendons, joints, or bone. Local muscle flaps were selected over free flaps if the defect was small (3 x 6 cm or less) and within reach of the local muscle flap. During the same time frame, the authors performed 45 free flaps (96 percent success rate) in the same areas when the defects were too large or out of reach of local muscle flaps. Thirty-two consecutive patients underwent local muscle flap reconstruction for 19 diabetic wounds and 13 traumatic wounds. All wounds, after debridement, had exposed bone at their base, with osteomyelitis being present in 52 percent of the diabetic wounds and in 70 percent of the nondiabetic wounds. Wounds were located in the hindfoot (47 percent), midfoot (44 percent), and ankle (9 percent). Vascular disease was more prevalent in the diabetic group, in which 42 percent of the affected limbs required revascularization procedures before reconstruction (versus 7 percent in the nondiabetic group). Subsequently, 83 total operations were required to heal the wounds, of which 46 percent were limited to debridement only. Thirty-four pedicled muscle flaps were used: 19 abductor digiti minimi (56 percent), nine abductor hallucis (26 percent), three extensor digitorum brevis (9 percent), two flexor digitorum brevis (6 percent), and one flexor digiti minimi (3 percent). An additional skin graft for complete coverage was required in 18 patients (53 percent). One patient died and one flap developed distal necrosis, for a 96 percent success rate. The complication rate was 26 percent and included patient death, dehiscence, and partial flap or split-thickness skin graft loss. Twenty-nine of the 32 wounds healed. One patient died in the postoperative period; in two others the wounds failed to heal and required below-knee amputations, for an overall limb salvage rate of 91 percent. Diabetes did not significantly affect healing and limb salvage rates. Diabetes, however, did affect healing times (twofold increase), length of stay (2.7 times as long), and long-term survival (63 percent survival in diabetic patients versus 100 percent in the trauma group). Local muscle flaps provide a simpler, less expensive, and successful alternative to microsurgical free flaps for foot and ankle defects that have exposed bone (with or without osteomyelitis), tendon, or joint at their base. Diabetes does not appear to adversely affect the effectiveness of these flaps. Local muscle flaps should remain on the forefront of possible reconstructive options when treating small foot and ankle wounds that have exposed bone, tendon, or joint.     

Validation of a model for the study of multiple wounds in the diabetic mouse (db/db)

The genetically diabetic db/db mouse exhibits symptoms that resemble human type 2 diabetes mellitus, demonstrates delayed wound healing, and has been used extensively as a model to study the role of therapeutic topical reagents in wound healing. The purpose of the authors' study was to validate an excisional wound model using a 6-mm biopsy punch to create four full-thickness dorsal wounds on a single db/db mouse. Factors considered in developing the db/db wound model include reproducibility of size and shape of wounds, the effect of semiocclusive dressings, comparison with littermate controls (db/-), clinical versus histologic evidence of wound closure, and cross-contamination of wounds with topically applied reagents. The size of wounds was larger, with less variation in the db/db mice (31.11 +/- 3.76 mm2) versus db/- mice (23.64 +/- 4.78 mm2). Wounds on db/db mice that were covered with a semiocclusive dressing healed significantly more slowly (mean, 27.75 days) than wounds not covered with the dressing (mean, 13 days; p < 0.001), suggesting the dressings may splint the wounds open. As expected, wounds healed more slowly on db/db mice than db/- mice (covered wounds, 27.75 days versus 11.86 days, p < 0.001; wounds not covered, 13 days versus 11.75 days, p = 0.39). Covered wounds, thought to be closed by clinical examination, were confirmed closed by histology only 62 percent of the time in the db/db and 100 percent of the time in the db/- mice. Topical application of blue histologic dye or soluble biotinylated laminin 5 to one of the four wounds did not spread locally and contaminate adjacent wounds. Multiple, uniform, 6-mm wounds in db/db mice heal in a relatively short time, decrease the number of animals needed for each study, and allow each animal to serve as its own control. The db/db diabetic mouse appears to be an excellent model of delayed wound healing, particularly for studying factors related to epithelial migration.     

Induction of airway collapse with subatmospheric pressure in awake patients with sleep apnea

To determine whether the pharyngeal airway is abnormal in awake patients with obstructive sleep apnea (OSA), we measured the ability of the pharyngeal airway to resist collapse from subatmospheric pressure applied to the nose in awake subjects, 12 with OSA and 12 controls. Subatmospheric pressure was applied to subjects placed in the supine position through a tightly fitting face mask. We measured airflow at the mask as well as mask, pharyngeal, and esophageal pressures. Ten patients developed airway obstruction when subatmospheric pressures between 17 and 40 cmH2O were applied. Obstruction did not occur in two patients with the least OSA. Obstruction did not occur in 10 controls; one obese control subject developed partial airway obstruction when -52 cmH2O was applied as did another with -41 cmH2O. We conclude that patients with significant OSA have an abnormal airway while they are awake and that application of subatmospheric pressure may be a useful screening test to detect OSA.     

Quantitative characteristics of changes in the cellular composition and vascularization of aseptic wounds in rat skin, healing without treatment and during stimulation of repair processes by exogenous collagen

The changes in cellular composition and vascularization of aseptic wounds on the rat skin were assessed quantitatively using the ocular net without treatment and during stimulation of repair processes by exogenous collagen. An intensive increase in the number of macrophages, endotheliocytes and fibroblasts was observed in wounds without treatment by the fifth day, with maximum vascularization of the granulation tissue occurring by the seventh day. During stimulation of repair processes by collagen the macrophage reaction, proliferation of endotheliocytes and fibroblasts and vascularization of wounds were activated earlier, while the stereotype relationships of the cellular components remained unchanged. The intercellular relationships of the wound healing process are discussed.     

Microencapsulated VEGF gene–modified umbilical cord mesenchymal stromal cells promote the vascularization of tissue-engineered dermis: an experimental study

Background aimsTissue-engineered dermis (TED) is thought to be the best treatment for skin defect wounds; however, lack of vascular structures in these products can cause slow vascularization or even transplant failure. We assessed the therapeutic potential of microencapsulated human umbilical cord mesenchymal stromal cells (hUCMSCs) expressing vascular endothelial growth factor (VEGF) in vascularization of TED.MethodshUCMSCs were isolated by means of enzymatic digestion and identified by means of testing biological characteristics. hUCMSCs were induced to differentiate into dermal fibroblasts in conditioned induction media. Collagen-chitosan laser drilling acellular dermal matrix (ADM) composite scaffold was prepared by means of the freeze dehydration and dehydrothermal cross-linking method. hUCMSC-derived fibroblasts were implanted on composite scaffolds to construct TED. TED with microencapsulated VEGF gene–modified hUCMSCs was then transplanted into skin defect wounds in pigs. The angiogenesis of TED at 1 week and status of wound healing at 3 weeks were observed.ResultsThe collagen-chitosan laser ADM composite has a uniform microporous structure. This composite has been used to grow hUCMSC-derived fibroblasts in vitro and to successfully construct stem cell–derived TED. Microencapsulated VEGF gene–modified hUCMSCs were prepared with the use of a sodium alginate–barium chloride one-step encapsulation technology. Seven days after the transplantation of the stem cell–derived TED and microencapsulated VEGF gene–modified hUCMSCs into the skin defect wounds on the backs of miniature pigs, the VEGF expression increased and the TED had a higher degree of vascularization. Re-epithelialization of the wound was completed after 3 weeks.ConclusionsMicroencapsulated VEGF gene–modified hUCMSCs can effectively improve the vascularization of TED and consequently the quality of wound healing.     

Frontoethmoidal encephalomeningocele: surgical correction by the Chula technique

This study reevaluates a surgical technique known as the Chula technique, previously reported in 1991 for correction of frontoethmoidal encephalomeningocele. From 1986 to 1999, 108 patients were operated on with this technique, which could remove the herniation mass, repair dural and bone defects, reconstruct the naso-orbital area, and restore aesthetic facial appearance in a single stage. Formal frontal craniotomy was not necessary. The result has been very satisfying in terms of safety, cure rate, and aesthetic outcome. Spontaneous improvement of lacrimal passage obstruction occurred in 85.2 percent of cases, and dacryocystorhinostomy was required in the rest. There was no mortality. Complications (e.g., wound infection, 6.5 percent; wire extrusion, 3.7 percent; meningitis, 2.8 percent; cerebrospinal fluid leakage, 2.8 percent; and postoperative increased intracranial pressure, 2.8 percent) were much less frequent than in other reports. With a mean follow-up period of 439 days (maximum, 12 years), there has been no recurrence.     

Management of sternal wounds with bilateral pectoralis major myocutaneous advancement flaps in 114 consecutively treated patients: refinements in technique and outcomes analysis

Because life-threatening sternal wound complications can occur following sternotomy, the optimal management of sternal wound infections remains an important topic. To decrease morbidity following operative treatment of these patients, the authors made a number of refinements in their treatment protocol over the past several years, particularly with regard to the extent of débridement, method of flap apposition, and management of drains. The purpose of this study was to obtain specific outcomes data by reviewing a large series of patients treated by a single surgeon. In this series of 114 consecutive sternal wounds treated by the senior author (Ascherman), patients were managed almost exclusively with débridement and immediate closure with bilateral pectoralis major myocutaneous advancement flaps. There were no intraoperative deaths. The 30-day perioperative mortality rate was 7.9 percent, with only one death directly related to sternal infection. Nineteen patients (16.7 percent) experienced postoperative morbidity, including partial wound dehiscences (5 percent), skin edge necrosis (5 percent), and seromas (3.5 percent). The authors advocate single-stage management of complicated sternal wounds with immediate débridement and bilateral pectoralis major myocutaneous advancement flaps. The procedure is rapid and effective. Refinements in technique have significantly lowered morbidity.     

Clinical trials of amniotic membranes in burn wound care

Four test conditions of increasing complexity were used to evaluate the clinical efficacy of amniotic membranes as biologic dressings on donor sites and burn wounds in children. These were the clean-skin donor-site wound, the uncontaminated shallow partial-thickness burn wound, the bed of freshly excised full-thickness wounds, and the granulating surface of colonized burn wounds. The rate of epithelialization under amniotic membranes was the same as that under 5% scarlet red ointment or 0.5% silver nitrate solution dressings. Preservation of a healthy excised wound bed and maintenance of a low bacterial count in contaminated wounds paralleled the experience with human allograft dressings despite technical difficulties and the absence of vascularization of amniotic membrane and its fragile structure. Tentative conclusions are drawn as to the mechanisms by which biologic dressings exert their beneficial effects.