The periodontal ligament, temperature-sensitive ion channels TRPV1-4, and the mechanosensitive ion channels Piezo1 and 2: A Nobel connection.

Teeth are subject to a variety of mechanical forces and vectors. The periodontal ligament (PDL), fibrous tissue that connects the cementum of the tooth to the bony socket, plays a decisive role in transmitting force to alveolar bone via Sharpey fibers, transforming and converting these forces into biological signals. This interaction effects significant osteoblastic and osteoclastic responses via autocrine proliferative and paracrine responses. Recent discoveries of receptors for temperature and touch by the Nobel laureates David Julius and Ardem Patapoutian, respectively have a profound impact on orthodontics. Transient receptor vanilloid channel 1 (TRPV1), initially described as a receptor for temperature, has been proposed to participate in the sensing of force. TRPV4, another ion channel receptor, perceives tensile forces as well as thermal and chemical stimuli. Piezo1 and 2, the classic receptors for touch, in addition to the aforementioned receptors, have similarly been described on PDL-derived cells. In this text, we review the role of the temperature-sensitive ion channels and mechanosensitive ion channels on their biological function and influence in orthodontic treatment.

Healing Time Correlates With the Quality of Scaring: Results From a Prospective Randomized Control Donor Site Trial.

BACKGROUND: Scar formation remains a potential problem after surgery or trauma. Factors influencing scar tissue have been recognized, most notably healing time and wound depth. OBJECTIVE: To examine the association between healing time and the quality of scar tissue formation. MATERIALS AND METHODS: Scarring was assessed at 3 and 12 months after treatment in an RCT of 219 patients and consecutive 438 split-thickness skin graft donor sites. The primary end point of the study was healing time and the quality of scar tissue, which was scored by a validated scar scale evaluating scar height, surface, and color. RESULTS: The mean time of wound healing was 15.8 days, with a mean scar score of 6.89 at 3 months and 4.66 at 12 months. There was a significant (p < .000001) and linear correlation between healing time and scar quality. Of particular note, at 12 months, all subparameters of the score demonstrated worsening with prolonged time to heal. CONCLUSION: The authors could objectively demonstrate that epithelialization time is an important factor influencing scar quality. In contrast to previous assumptions, this correlation follows linearly. It is reasonable then to assume that treatment strategies expediting healing will also improve scar outcome.

Injection of SVF combined with HBO2 improves viability of unfavorably designed flaps.

PURPOSE: Soft-tissue reconstruction is complicated by ischemia and reperfusion injury. Animal trials have documented the independent healing benefits of hyperbaric oxygen preconditioning (HBOP) and stem cell delivery in cutaneous flaps. We explored the role of HBOP and stem cell delivery in flap preconditioning and survival. METHODS: We designed a randomized controlled trial to assess the effects of hyperbaric oxygen preconditioning and stromal vascular fraction (SVF) delivery on flap survival. Of the first 24 guinea pigs, six received neither HBOP nor injections, and six underwent HBOP without injections. Of the remaining 12 animals, six received SVF or saline injections in the absence of HBOP. The final six animals received autologous SVF injections or saline injections followed by four HBOP treatments. To enhance clinical relevance, a group of 6 animals underwent HBOP prior to SVF or saline injections. Thereafter, an unfavorably designed cutaneous flap was elevated and assessed via study-blinded observer, as well as by quantification of TUNEL-positive cells. RESULTS: Distal necrosis of the tissue flap was more extensive in the no-intervention group (45% of flap). Flaps treated with HBOP only and those treated with SVF injections demonstrated only 38.2% and 27.1% distal necrosis. The most significant difference occurred in the combination HBOP and SVF group, where distal necrosis was only 21.1% of the flap (p ≤ 0.05). SVF delivery immediately prior to flap elevation further minimized distal necrosis of the flap to 15.6%. These findings were mirrored by the TUNEL assay. CONCLUSIONS: Combining HBOP and SVF improves flap viability.

The Use of Dehydrated Human Amnion/Chorion Membranes in the Treatment of Burns and Complex Wounds: Current and Future Applications.

Historically, biologic materials found in nature have been used for a wide variety of medicinal purposes, although their widespread use may be limited due to challenges in obtaining and properly preparing the material for safe clinical use. Amniotic membrane has long been recognized to possess unique properties favorable for healing. Dehydrated human amnion/chorion membrane allografts are commercially available for use in multiple sizes and configurations applicable for a variety of clinical settings and presentations. The purpose of this article is to review the therapeutic properties of amniotic membrane.

Primary Cutaneous γδ T-Cell Lymphoma and Hemophagocytic Syndrome.

Primary cutaneous γδ T-cell lymphoma and hemophagocytic syndrome (HPS) is a very rare disease process with only 41 cases of this type of lymphoma published to date. We report the case of a 56-year-old woman who developed high-grade fevers and multiple nonhealing bilateral lower extremity ulcers associated with a recent diagnosis of Ackerman syndrome. Multiple lesion biopsies yielded a differential diagnosis including sarcoidosis and lupus panniculitis. Each biopsy site developed into a poorly healing wound. After extensive rheumatologic and dermatologic workup, failed courses of hyperbaric oxygen and corticosteroids, and the development of worsening fevers, the diagnosis of γδ T-cell lymphoma was made. The objective of this article was to illustrate a very rare case of a rapidly progressing cutaneous lymphoma while stressing the importance of a surgical approach to nonhealing wounds and biopsy in chronic wounds.An aggressive multidisciplinary approach including infectious disease, hematology/oncology, nephrology, plastic surgery, and interventional pulmonology was used. Medical approaches included several courses of corticosteroids and antineoplastics. Our surgical approach included numerous excision and debridements of her nonhealing ulcers with removal of necrotic tissue. It also included placement of cadaveric epidermal graft, and bovine tendon collagen cross-linked with glycosaminoglycans with a silicone matrix bilayer (Integra, Plainsboro, NJ) combined with multiple local myocutaneous advancement flaps. This approach demonstrated clinical improvement in wound healing. Pathological examination of several lesions included immunohistochemistry staining, flow cytometry, and molecular studies.The diagnosis of primary cutaneous γδ T-cell lymphoma was made based on a pathology specimen. Subsequent imaging showed numerous pulmonary nodules later determined to be pulmonary Aspergillosis. Additionally, she developed a constellation of clinical and laboratory features defined as the HPS. Despite medical therapy and improved wound healing, she died to seizures that left her comatose, thought to be secondary to central nervous system advancement of her HPS. The patient eventually died after care was withdrawn.Cutaneous forms of lymphoma must be considered in the differential diagnosis of atypical cutaneous lesions or nonhealing wounds. There should be no delay in performing a skin biopsy to obtain a tissue diagnosis. A surgical approach to wounds clearly demonstrates improved wound healing.

Dental health concerns for patients suffering from facial, peri-oral burns, and inhalation injury: A persistent yet underappreciated challenge.

Demographic data reveal a correlative relationship between facial burns and profoundly impaired dental health, while inhalation injury correlates with a high Periodontal Screening and Recording Index, both of which significantly reduce quality of life for the burn injury patient. Despite these facts, few if any burn centers surveyed in the U.S. or Germany enlist specialized services and well-defined follow-up protocols for patients who might well be at risk. Facial burns represent a severe injury, the consequence of which may tragically lead to significant and long lasting functional, esthetic, and psychological sequelae such as perioral scarring, deformity and microstomia. Inhalation injury from inhaled heated air, gas, and chemical exposure are well-known causes of early as well as late airway injury, morbidity, and death. Thermal injury patterns to perioral-related and dental structures is increasingly being recognized. This review delineates current burn-related dental health pathology and when available the underlying causation. These findings may help guide future research as well as therapeutic strategies to improve dental health and outcome for our patients.

Roles of Mechanosensitive Channel Piezo1 in Wound Healing and Scar Formation.

The ability to heal one's wounds is perhaps one of the most fundamental and critical of physiologic processes. This coordinated and closely regulated sequential biological process involves a variety of migratory and resident cells. The activation, modulation, balance, and control of these functions depend upon soluble mediators that activate cells and modulate their diverse functions. Recent advances have identified mechanotransduction as functionally integral in many different cell types and physiologic processes. The mechanically sensitive ion channel Pieoz1 is expressed on platelets, neutrophils, macrophages, endothelial cells, keratinocytes, and fibroblasts, all of which are principally involved in wound healing. On a cellular level, there have been great advances in our understanding of the functional role of Piezo1 mechanotransduction in cutaneous wounding. The blocking of Piezo1 has recently been shown to reduce scarring in vivo and yet, thus far, a comprehensive understanding of the roles that Piezo1 plays in in vivo wound healing remains lacking. Recognizing the ever-present and critical importance of optimal and reparative wound healing, and with the availability of new physical mechanomodulating devices, the time is ripe for gaining deeper insights into optimizing wound healing. In this review, we describe the current knowledge of Piezo1 related to wound healing.

Encircling the tendon repair site with collagen-GAG reduces the formation of postoperative tendon adhesions in a chicken flexor tendon model.

BACKGROUND: Tendon healing is a complex and coordinated event involving the activation of extrinsic mechanisms as in classic reparative skin wound healing as well as intrinsic mechanisms characteristic of regenerative wound healing. Despite improvements in surgical and rehabilitative techniques, tendon adhesions remain the most frequent cause of disability following tendon surgery. In this animal model, we evaluated the use of a clinically available, biocompatible collagen- glycosaminoglycan (GAG) material as an adjunct to surgical tendon repair. METHODS: Thirty-two white leghorn chickens underwent surgical tendon repair of their left second and fourth digits. Digits were randomized to study and control groups. In both groups, the long flexor tendon was divided and repaired using a modified Kessler's repair. In the study group, collagen-GAG membrane was wrapped around the repair site. Animals were immobilized with a plaster cast and sacrificed at 3 wk. Sixteen animals had their tendon repair sites histologically assessed and graded for healing and adhesion formation. Eight animals had their tendon repairs assessed for quantification of the work associated with flexion, employing a specifically designed biomechanical apparatus. Eight animals had their repair sites tested for bursting strength. RESULTS: Control (untreated) tendons showed fibrous tissue surrounding the repair sites with approximately 50% of the circumference of the repair site adherent to surrounding tissue elements. The mean histologic grades for control and study group were 3.1+/-0.2 and 1.9+/-0.2, respectively. The difference between mean grades for control and study group samples was statistically significant (paired t-test: P<0.01). The work of flexion (WOF) for flexion cycles 1, 2, 3, and 4 for the control group was 0.58, 0.55, 0.46, and 0.44N/mm, respectively. The study (collagen-GAG wrapped) group had WOF values 0.16, 0.14, 0.10, 0.09N/mm, and the difference between the groups was statistically significant (paired t-test, P<0.01). The mean bursting strength of repaired tendons for control and study groups were 14.3+/-1.87N and 11.5+/-1.85N, respectively. There was no significant difference in bursting strength between the groups (paired t-test, P=0.71). CONCLUSIONS: Collagen-GAG reduces formation of early postoperative tendon adhesions in this chicken flexor tendon repair model. Collagen-GAG wrapped tendons healed with minimal peritendinous adhesion formation and required less effort for flexion. The investing collagen-GAG membrane did not appear to interfere with either the quality or strength of healing.

Minimal Scar Formation After Orthopaedic Skin Incisions Along Main Folding Lines.

BACKGROUND: Patients, particularly those who are young, often develop noticeable orthopaedic scars. In order to achieve minimal scarring, surgeons should attempt to place incisions in skinfolds or skin creases. METHODS: Optimal incision lines can be determined from the direction of stretch marks (striae distensae), which develop perpendicular to lines of tension or main folding lines. A composite diagram of photographs of 213 individuals with striae distensae was created and compared with 276 images of incisions and scars derived from the Internet. RESULTS: Classically described Langer cleavage lines often run counter to real tension lines and poorly predict the optimal direction for skin incisions. CONCLUSIONS: Whenever possible, main folding lines should be utilized as a guide in planning surgical incisions for young patients as well as for correction of problem scars.

A brief historical review of flaps and burn reconstruction.

 Thermal, chemical, and electrical injuries contribute to some of the most disabling and deforming wound injury patterns. These challenges, ultimately cared for by burn and reconstructive specialists, require an evolution in the understanding of functional and aesthetic prioritization, 3-dimensional geometric rearrangement of tissues, anatomic considerations of neurovascularized constructs, as well as the development of fundamental technical skills. Flaps, generally defined as tissue constructs, transferred along with a defined vascular supply are considered principle elements in the armamentarium of the reconstructive specialist. The transfer and design of these flaps can augment most tissue type deficits, protect or transfer functional neurovascular and musculotendinous structures, and provide bone and durable soft tissue elements to restore both form and function. The history of flap construct and reconstruction precedes available written text and spans independent cultural, temporal and geographic divides. Several key flaps currently utilized in burn and reconstructive surgery will be reviewed with some historical context provided. A comprehensive review of the history of flaps in reconstructive surgery certainly exceeds the scope of any simplistic chapter or text.

Preclinical assessment of safety and efficacy of intravenous delivery of autologous adipose-derived regenerative cells (ADRCs) in the treatment of severe thermal burns using a porcine model.

OBJECTIVE: A number of studies have reported that application of autologous adipose-derived cell populations leads to improved outcome in different preclinical models of thermal burn injury. However, these studies were limited to assessment of relatively small injuries amounting to only ∼2% of total body surface area (TBSA) in which the complications associated with large burns (e.g.: systemic inflammation and the need for fluid resuscitation) are absent. In anticipation of translating this approach to a clinical trial in which these complications would be present we applied a preclinical model that more closely resembles a patient with large thermal burn injury requiring skin grafting. Thus, the present study used a porcine model to investigate safety and efficacy of intravenous delivery of ADRCs in the treatment of a complex burn injury comprising ∼20% TBSA and including both moderately deep (44%) partial and full thickness burns, and the injury associated with skin graft harvest. METHODS: Two pairs of full thickness and partial thickness burns involving in total ∼20% TBSA were created on the back of Yorkshire pigs (n=15). Three days post-burn, full thickness wounds were excised and grafted with a 3:1 meshed autologous split thickness skin graft (STSG). Partial thickness wounds were not treated other than with dressings. Animals were then randomized to receive intravenous delivery of ADRCs (n=8) or vehicle control (n=7). Safety was assessed by monitoring systemic parameters (blood gases, hematology, and clinical chemistry) throughout the course of the study. Wound healing for both types of burn wound and for the skin graft donor sites was followed for 18days using wound imaging, histology, and trans-epidermal water loss (TEWL; skin barrier function assessment). RESULTS: No serious adverse events related to ADRC infusion were noted in any of the animals. Delivery of ADRCs appeared to be safe with none of the systemic safety parameters worsened compared to the control group. TEWL and histological analyses revealed that ADRC treatment was associated with significantly accelerated healing of skin graft (27.1% vs. 1.1% on Day 5 post-grafting), donor site (52.8% vs. 33.1% on Day 5 post-excision) and partial thickness burn (81.8% vs. 59.8% on Day 18 post-treatment). Data also suggested that ADRC treatment improved parameters associated with skin graft elasticity. CONCLUSIONS: This study demonstrated that intravenous delivery of autologous ADRCs appears to be a safe and feasible approach to the treatment of large burns and supports the use of ADRCs as an adjunct therapy to skin grafting in patients with severe burns.

Interleukin-6 Serum Levels Correlate With Severity of Burn Injury but Not With Gender.

Gender-specific differences in the outcome of patients with burn injury have been recognized in the past with female patients being at a higher risk of mortality. We hypothesized that early post-burn interleukin-6 (IL-6) cytokine levels may contribute to the different gender-specific outcome. We retrospectively examined 94 burned patients who were treated in the Burn Intensive Care Unit at the University Hospital Aachen. Age, gender, presence of inhalation injury, depth, TBSA, and clinical outcome were documented. Serum samples for IL-6 analysis were collected within 24 hours posttrauma. The relationship between IL-6 levels, gender, survival, and abbreviated burn severity index score was investigated. Male patients (64.9%; n = 61) presented a higher median TBSA (26%) than female patients (20%). The mortality rate of male patients (27.9%; n = 17) and female patients (21.2%; n = 7) was similar. Deceased patients had significant higher TBSA (P = 0.0005) and IL-6 levels (P = 0.0007) than burn survivors. A moderate correlation between IL-6 levels and abbreviated burn severity index score was observed (r = 0.554; P < 0.0001). While TBSA showed a significant influence on IL-6 levels (P = 0.0003), gender did not (P = 0.7395) and inhalation injury indicated a minor influence (P = 0.0780). Only TBSA and age presented a significant influence on mortality (P = 0.0028 and P = 0.0031, respectively). All patients with burn trauma were characterized by elevated IL-6 levels with higher TBSA values resulting in more pronounced levels. Deceased patients had higher initial IL-6 serum levels reflecting higher TBSA and severity. In contrast to other defined trauma mechanisms, gender had no significant influence on postburn IL-6 serum levels and mortality in our patient population.

Comparison of wound irrigation and tangential hydrodissection in bacterial clearance of contaminated wounds: results of a randomized, controlled clinical study.

Thorough irrigation of contaminated or infected traumatic and open surgical wounds is considered standard practice. High-power pulse lavage is frequently used to facilitate the removal of surface contaminants and bacteria but studies to compare the results of various irrigation techniques are limited. The purpose of this randomized, controlled clinical study was to compare the ability of a high-pressure parallel waterjet (pressure range 5,025 to 7,360 psi) to pulse lavage (pressure 40 psi) in reducing wound bacterial counts. The higher velocity instrument utilizes a waterjet oriented parallel to the surface of the wound and can be used to cut and remove necrotic tissues. After obtaining informed consent, 21 patients who presented with open surgical and traumatic wounds were randomly assigned to high-pressure parallel waterjet (n = 12) or pulse lavage (n = 9). Pre- and post irrigation tissue culture results showed an average decrease in absolute bacterial counts of 90.8% in the high-pressure parallel waterjet and 86.9% in the pulse lavage group. The difference between the two treatment groups was not statistically significant. The results of this study confirm that cleansing contaminated or infected acute wounds using high pressure (at least 15 psi) reduces wound bacterial counts. Studies to compare the clinical outcomes of various irrigation techniques and pressure ranges are warranted and the potential benefit of selective debridement using the high-pressure parallel waterjet should be investigated.

Staged Repair of an Aortic Pseudoaneurysm Secondary to Delayed Methylmethacrylate Plate Migration.

Methylmethacrylate is a prosthetic material commonly used for the reconstruction of large chest wall defects. We present the first reported case of delayed methylmethacrylate plate migration, which resulted in an aortic pseudoaneurysm with aortopulmonary fistula. Treatment management, including staged repair combining endovascular and open approaches, is also discussed.

Autologous adipose-derived regenerative cell therapy modulates development of hypertrophic scarring in a red Duroc porcine model.

BACKGROUND: Effective prevention and treatment of hypertrophic scars (HTSs), a common consequence of deep-partial thickness injury, remain a significant clinical challenge. Previous studies from our group have shown that autologous adipose-derived regenerative cells (ADRCs) represent a promising approach to improve wound healing and, thereby, impact HTS development. The purpose of this study was to assess the influence of local delivery of ADRCs immediately following deep-partial thickness cutaneous injury on HTS development in the red Duroc (RD) porcine model. METHODS: Bilateral pairs of deep-partial thickness excisional wounds (2 mm depth; 58 cm2 area) were created using an electric dermatome on RD pigs (n = 12). Autologous ADRCs were isolated from the inguinal fat pad and then sprayed directly onto the wound at a dose of 0.25 × 106 viable cells/cm2. The paired contralateral wound received vehicle control. Wound healing and development of HTS were assessed over 6 months using digital imaging, quantitative measurement of skin hardness and pigmentation, and histology. RESULTS: Data showed that ADRC treatment led to reduced scar hyperpigmentation compared to control (p < 0.05). Using the Durometer, at 2 and 6 months post-injury, skin hardness was 10-20% lower in ADRCs-treated wounds compared to control vehicle (p < 0.05). A similar trend was observed with the skin fibrometer. ADRC treatment promoted more normal collagen organization, improvement in the number of rete ridges (p < 0.01), longer elastic fiber length (p < 0.01), and reduced hypervascularity (blood vessel density; p < 0.05). ADRC treatment was associated with modulation of IL-6 expression within the wound/scar with upregulation 2 weeks after injury (wound healing phase) and downregulation at 2 months (early scarring phase) post-treatment compared to control CONCLUSIONS: These findings support the potential therapeutic value of autologous ADRC administration for reduction of HTS development following deep-partial cutaneous injury.

Development of a combined radiation and full thickness burn injury minipig model to study the effects of uncultured adipose-derived regenerative cell therapy in wound healing.

PURPOSE: To develop an approach that models the cutaneous healing that occurs in a patient with full thickness thermal burn injury complicated by total body radiation exposure sufficient to induce sub-lethal prodromal symptoms. An assessment of the effects of an autologous cell therapy on wound healing on thermal burn injury with concomitant radiation exposure was used to validate the utility of the model. METHODS: Göttingen minipigs were subjected to a 1.2 Gy total body irradiation by exposure to a 6 MV X-ray linear accelerator followed by ∼10 cm2 full thickness burns (pre-heated brass block with calibrated spring). Three days after injury, wounds were excised to the underlying fascia and each animal was randomized to receive treatment with autologous adipose-derived regenerative cells (ADRC) delivered by local or intravenous injection, or vehicle control. Blood counts were used to assess radiation-induced marrow suppression. All animals were followed using digital imaging to assess wound healing. Full-thickness biopsies were obtained at 7, 14, 21 and 30 days' post-treatment. RESULTS: Compared to animals receiving burn injury alone, significant transient neutropenia and thrombocytopenia were observed in irradiated subjects with average neutrophil nadir of 0.79 × 103/µl (day 15) and platelet nadir of 60 × 103/µl (day 12). Wound closure through a combination of contraction and epithelialization from the wound edges occurred over a period of approximately 28 days' post excision and treatment. Re-epithelialization was accelerated in wounds treated with ADRC (mean 3.5-fold increase at 2 weeks post-treatment relative to control). This acceleration was accompanied by an average 67% increase in blood vessel density and 30% increase in matrix (collagen) deposition. Similar results were observed when ADRC were injected either directly into the wound or by intravenous administration. CONCLUSIONS: Although preliminary, this study provides a reproducible minipig model of thermal burn injury complicated by myelosuppressive total body irradiation that utilizes standardized procedures to evaluate novel countermeasures for potential use following attack by an improvised nuclear device.

Debridement of burn wounds with a water jet surgical tool.

A new instrument, the Versajet system, based on fluid jet technology has recently been advocated as an alternative to standard surgical excisional technique for burn wounds. In this paper we describe our experience with this tool, the technique employed as well as its clinical feasability for debriding partial thickness burn wounds. Seventeen patients were evaluated for clinical efficacy of debridement of their burn wounds using the Versajet system. Burn wound areas of between 0.5 and 5% total body surface (TBSA) involving the face, arm, hand, leg and foot underwent debridement using the Versajet system. The Versajet system was able to sufficiently debride superficial partial thickness and mid-dermal partial thickness wounds for subsequent placement of Biobrane. Deeper partial thickness wounds could be excised for successful autografting. The Versajet system demonstrated some particular advantage in the surgical treatment of superficial to mid-partial thickness burns in areas like the face, hand and foot which can often be difficult to reach and contour with conventional modalities.

Current Concepts in Tissue Engineering: Skin and Wound.

BACKGROUND: Pure regenerative healing with little to no donor morbidity remains an elusive goal for both surgeon and patient. The ability to engineer and promote the development of like tissue holds so much promise, and efforts in this direction are slowly but steadily advancing. METHODS: Products selected and reviewed reflect historical precedence and importance and focus on current clinically available products in use. Emerging technologies we anticipate will further expand our therapeutic options are introduced. The topic of tissue engineering is incredibly broad in scope, and as such the authors have focused their review on that of constructs specifically designed for skin and wound healing. A review of pertinent and current clinically related literature is included. RESULTS: Products such as biosynthetics, biologics, cellular promoting factors, and commercially available matrices can be routinely found in most modern health care centers. Although to date no complete regenerative or direct identical soft-tissue replacement exists, currently available commercial components have proven beneficial in augmenting and improving some types of wound healing scenarios. Cost, directed specificity, biocompatibility, and bioburden tolerance are just some of the impending challenges to adoption. CONCLUSIONS: Quality of life and in fact the ability to sustain life is dependent on our most complex and remarkable organ, skin. Although pure regenerative healing and engineered soft-tissue constructs elude us, surgeons and health care providers are slowly gaining comfort and experience with concepts and strategies to improve the healing of wounds.

Description of a Simple Method of Stoma Protection During Prone Positioning.

Surgeries conducted with the patient in the prone position are frequent and can be lengthy. Abdominal stomas and su- prapubic catheters require protection for the complete duration of the procedure to avoid complications such as stomal ischemia, bleeding, or mucocutaneous separation. Standard protection strategies such as pillows and wedges can eas- ily fail. In the course of managing several patients who had sustained ostomy complications following surgery in a prone position, a simple method of stoma protection was devised. Instead of discarding the foam headrest typically used dur- ing induction by anesthesia staff, this device is placed with its central recess over the stoma and secured to the patient's abdominal wall with gentle tape just before turning the patient into a prone position. This method, used in more than 80 patients, has been found to effectively relieve pressure, and no complications have been observed. The foam shape also enables unobstructed drainage of fluids, facilitating collection and preventing leakage and contamination of the surgical field. Because the device is widely used by anesthesia, it is readily available and does not add any extra cost.

Adipose-Derived Regenerative Cell Therapy for Burn Wound Healing: A Comparison of Two Delivery Methods.

Objective: The use of noncultured autologous stromal vascular fraction or clinical grade adipose-derived regenerative cells (ADRCs) is a promising strategy to promote wound healing and tissue repair. Nevertheless, issues regarding the optimal mode of administration remain unclear. The purpose of this study was to compare the effects of local injection and topical spray delivery of ADRCs in a porcine model of thermal burns. Approach: Full-thickness thermal burns were created on the dorsum of 10 Gottingen minipigs. Two days following injury, wounds underwent fascial excision and were randomized to receive control vehicle or freshly isolated autologous ADRCs delivered by either multiple injections into or surrounding the wound bed, or by spray onto the wound surface (0.25 × 106 viable cells/cm2). Healing was evaluated by planimetry, histopathology, and immunohistochemistry at day 7, 12, 16, 21, and 28 posttreatment. Results:In vitro analysis demonstrated that there was no substantial loss of cell number or viability attributable to the spray procedure. Planimetric assessment revealed that delivery of ADRCs by either local injection or topical spray increased wound reepithelialization relative to control at day 14. No significant difference in wound reepithelialization was observed between both delivery approaches. In addition, on day 7 posttreatment, blood vessel density was greater in wounds receiving local or topical spray ADRCs than in the wounds treated with vehicle control. Histopathologic analysis suggests that ADRC treatment may modulate the inflammatory response by reducing neutrophil infiltration at day 7 and 12 posttreatment, irrespective of the route of administration. Conclusions: These data demonstrate that local injection and spray delivery of ADRCs modulate inflammation and improve wound angiogenesis and epithelialization. Importantly, both delivery routes exhibited similar effects on wound healing. Given the greater ease-of-use associated with topical spray delivery, these data support the use of a spray system for autologous ADRC delivery.