Mechanisms of action of microdeformational wound therapy.

Microdeformational Wound Therapy (MDWT) is a class of medical devices that have revolutionized the treatment of complex wounds over the last 20 years. These devices, are a subset of Negative Pressure Wound Therapy (NPWT), in which there is a highly porous interface material placed between the wound and a semi-occlussive dressing and connected to suction. The porous interface material acts to deform the wound on a micro scale promoting cellular proliferation. These devices appear to significantly improve the speed of healing in many wounds, facilitate granulation tissue formation and reduce the complexity of subsequent reconstructive operations. The mechanisms through which such effects are obtained are beginning to be better understood through basic research and clinical trials. Further work in this field is likely to yield devices that are designed to treat specific wound types.

Greater surgical precision of a flexible carbon dioxide laser fiber compared to monopolar electrosurgery in porcine myometrium.

The objective of this experimental animal study was to compare the surgical precision of a flexible CO2 laser fiber with that of monopolar electrosurgery in porcine myometrium. The subjects were 6 live adult non-pregnant female pigs. Linear injury to the uterine horns was created using a flexible CO2 laser fiber at 5W, 10W, and 15W and with monopolar electrosurgery at 10W, 20W, 30W, and 40W in both cut and coagulation modes. Hysterectomy was then performed in the live animals. Cross-sections of the tissue were processed and stained using Masson trichrome to differentiate damaged from undamaged myometrium. Measurement means were compared using analysis of variance with Tukey honest significant difference correction; p <.05 indicated significance. Incision width of the laser at 5W and 10W was significantly less than both monopolar coagulation at all power settings and monopolar cut at 30W and 40W (all p <.01), at 5W was also significantly less than monopolar cut at 10W (p = .03), and at 15W was significantly less than monopolar coagulation at 40W (p = .001). Incision depth of the laser at 5W was significantly less than monopolar coagulation at 40W and laser at 15W (both p = .01), at 15W was significantly greater than monopolar coagulation at 10W and monopolar cut at 10, 20, and 30W (p ≤.01), and increased proportional to power for all 3 energy types. Collateral thermal damage width at all laser power settings was significantly less than at all monopolar coagulation power settings (p ≤.04) with the exception of the laser at 15W compared with monopolar coagulation at 10W (p = .30), and at all laser power settings was significantly less than at all monopolar coagulation power settings (p <.001). Collateral thermal damage depth of the laser at 5W and 10W was significantly less than monopolar cut at 30W (p ≤.002) and increased proportional to power in monopolar coagulation mode but remained constant with the laser. Incising efficiency of the laser at 5W was significantly greater than monopolar coagulation at 10W (p = .04), at 10W was significantly greater than at all monopolar power settings (p ≤.007) except cut at 40W (p = .29), and at 15W was significantly greater than that of every other energy type and power setting tested (p ≤.04). These findings support the hypothesis that CO2 laser energy delivered via a flexible fiber system would exhibit greater surgical precision than monopolar electrosurgery, in both cut and coagulation modes, as defined by 3 parameters: incising efficiency, changes in incision depth compared with width as power increases, and variability in the resulting incision measurements. Because increased thermal damage has been associated with delayed tissue necrosis and adhesion formation, these findings prompt the design of a comparative survival animal study to assess additional clinically relevant parameters.

Preliminary report of in vitro reconstruction of a vascularized tendonlike structure: a novel application for adipose-derived stem cells.

INTRODUCTION: A greater supply of tendinous tissue can be obtained through tissue engineering technology with increasing application of adult stem cells. It is well known that adipose-derived stem cells (ADSCs), found in abundance in adipose tissue, have the same differentiating capacity as mesenchymal stem cells yet have the advantage of being easily isolated. In the present study, we combined the great facility of ADSCs to differentiate with the application of an external mechanical stimulus to successfully create an in vitro reconstructed tendonlike structure with a microcapillary network. MATERIALS AND METHODS: Hyalonect meshes (Fidia Advanced Biopolymers, Abano Terme, Padova, Italy) were used as scaffold. Human ADSCs were seeded onto the biomaterials, and the cell/scaffold constructs were cultured under mechanical stress for up to 15 days. Human tenocytes were used in the same conditions as control. Performance was assessed by histology, immunochemistry, ultrastructure, and biomolecular analysis. RESULTS: Adipose-derived stem cells seeded onto Hyalonect adhered and differentiated along the entire surface of the biomaterial and began to infiltrate within its structure. Subsequently, endothelial cells migrated, forming a capillary in the new extracellular matrix. CONCLUSIONS: This technique allowed for the creation of a vascularized tendon equivalent that could easily be detached from the bioreactor, thus facilitating its implant at the lesion site. These results highlight the biologic performance of biodegradable hyaluronic acid-based (HYAFF-11) scaffolds, which were shown to be suitable for deposition of the autologous extracellular matrix critical for ADSCs differentiation.

"Synchronous" multifocal necrotizing fasciitis.

BACKGROUND: Necrotizing fasciitis (NF) is an infection of the soft tissue, and is fatal if not promptly and aggressively treated. Although it is rare, it is not exceptional; nevertheless, its presentation may be misleading and may delay the diagnosis. We highlight the possible synchronous development of NF in multiple noncontiguous areas. CASE REPORT: A 44-year-old diabetic man with no history of trauma complained of nonspecific lower back pain, which he treated with analgesics and oral antibiotics. Erythema at the left arm appeared, and the general condition worsened. The patient was admitted to the Emergency Department, and NF was diagnosed at the right gluteus and left arm. CONCLUSION: "Synchronous" multifocality is not an expected presentation of NF, and it complicates the diagnosis and delays treatment, with a potentially negative impact on outcome.

Blood levels, apoptosis, and homing of the endothelial progenitor cells after skin burns and escharectomy.

BACKGROUND: Skin burns are an acute trauma involving an extensive vascular damage and an intense inflammatory response. Bone marrow-derived circulating endothelial progenitor cells (EPC) are known to migrate to sites of neovascularization in response to mediators (vascular endothelial growth factor and stromal cell-derived factor-1) released after trauma and ischemia, to contribute to wound healing, and to increase neovascularization of animal prefabricated flaps. Recent data showed an increase in EPC number in burned patients and a positive correlation between EPC number and total body surface area (TBSA) burnt, but data were limited to the first 5 days after thermal injury. METHODS: By using flow cytometry, we studied EPC (CD34, CD133, CD45, and KDR cells) blood levels, apoptosis, and homing (stromal cell-derived factor-1 receptor expression and CXC chemokine receptor 4) in a 1-month follow-up postburn in 25 patients with ≥15% TBSA burnt, at least grade II burns and escharectomy performed at days 5 to 6, with respect to 31 controls. RESULTS: EPC count at admission showed a positive linear correlation with TBSA burnt. The EPC blood levels of the patients were low (50.7 cells/mL±61.8 cells/mL) immediately after thermal injury, then increased with two peaks, at day 1 (188.3 cells/mL±223.2 cells/mL) and day 12 (253.1 cells/mL±430.7 cells/mL) with respect to controls (95.2 cells/mL±28.5 cells/mL, p<0.05), and then returned to normal levels in 1 month. EPC apoptotic rate and inflammatory parameters paralleled EPC blood count. No significant variations were found in CXC chemokine receptor 4 expression. CONCLUSIONS: Thermal injury and escharectomy seem to induce an intense response in EPC production. In particular, escharectomy could improve physiologic wound repair by increasing EPC levels.

Layers of the abdominal wall: anatomical investigation of subcutaneous tissue and superficial fascia.

INTRODUCTION: In recent times new surgical approaches have been developed, in which subcutaneous tissue is the primary object, such as flaps and fat removal techniques, but different descriptions and abundance of terminology persist in Literature about this tissue. AIM AND METHODS: In order to investigate the structure of abdominal subcutaneous tissue, macroscopic and microscopic analyses of its layers were performed in 10 fresh cadavers. Results were compared with in vivo CT images of the abdomen of 10 subjects. RESULTS: The subcutaneous tissue of the abdomen comprises three layers: a superficial adipose layer (SAT), a membranous layer, and a deep adipose layer (DAT). The SAT presented fibrous septa that defined polygonal-oval lobes of fat cells with a mean circularity factor of 0.856 ± 0.113. The membranous layer is a continuous fibrous membrane rich in elastic fibers with a mean thickness of 847.4 ± 295 µm. In the DAT the fibrous septa were predominantly obliquely-horizontally oriented, defining large, flat, polygonal lobes of fat cells (circularity factor: mean 0.473 ± 0.07). The CT scans confirm these findings, showing a variation of the thickness of the SAT, DAT and membranous layer according with the subjects and with the regions. DISCUSSION: The distinction of SAT and DAT and their anatomic differences are key elements in modern approaches to liposuction. The membranous layer appears to be also a dissection plane which merits further attention. According with the revision of Literature, the Authors propose that the term "superficial fascia" should only be used as a synonym for the membranous layer.

Flexor tendon injuries: Repair & Rehabilitation.

Flexor tendon injuries are common and occur mostly by penetrating trauma. Suspected flexor tendon injuries require a thorough clinical assessment and often are not isolated injuries. A detailed understanding of flexor tendon anatomy and spatial relationships is essential, especially when repairing multi-tendon injuries. Principles of flexor tendon repair include a strong suture construct, minimising gap formation between tendon ends, preserving tendon blood supply and providing a smooth repair interface. Moreover, adequate exposure of the zone of injury using full-thickness skin flaps and preservation of neurovascular and pulley structures is essential. In this article an overview of contemporary management strategies is presented. Today's hand surgeons and therapists can choose from a variety of treatment options when managing these important and potentially life-changing injuries.

Quiescent platelets stimulate angiogenesis and diabetic wound repair.

INTRODUCTION: Platelets partake in hemostasis, wound healing, and tumor growth. Although platelet-rich-plasma (PRP) has been used in surgery for several years, its mechanism of action and application methods are still poorly characterized. MATERIALS AND METHODS: A single unit of human platelets obtained by plateletpheresis was diluted in plasma and divided into three equal volumes. One volume was stored at room temperature as fresh platelets (RT), another volume was frozen by storage at -80 degrees C (FZ), and the third volume was frozen at -80 degrees C with 6% DMSO (FZ6). Plasma (PL) was used as control. Using flow cytometry, platelets were tested for platelet glycoprotein GPIb and annexin V binding, as survival and activation markers, respectively. Hemostatic function was assessed by thromboelastometry. In vivo, platelets were topically applied on 1 cm,(2) full-thickness wounds on db/db mice (n = 10/group) and healing was staged microscopically and macroscopically. RESULTS: All platelet preparations showed hemostatic ability. RT platelets were GPIb positive (nonactivated-quiescent platelets) and stimulated angiogenesis by threefold, and cell proliferation by fourfold in vivo. FZ platelets were positive for annexin V, indicating activated platelets and, in vivo, increased only wound granulation. FZ6 platelets contained 30% nonactivated-quiescent and 50% activated platelets and stimulated granulation, angiogenesis, cell proliferation, and promoted re-epithelialization in vivo. CONCLUSIONS: Platelets showed distinct mechanisms to induce hemostasis and wound healing. Quiescent platelets are required to induce angiogenesis in vivo. Platelets stored at room temperature and frozen with 6% DMSO and stored at -80 degrees C achieved optimal wound healing in diabetic mice.

Comparison of transverse carpal ligament and flexor retinaculum terminology for the wrist.

PURPOSE: To investigate the macroscopic anatomy and histological characteristics of the transverse carpal ligament and the flexor retinaculum of the wrist and to investigate their anatomical relationships and define appropriate terminology. METHODS: The volar regions of the wrists of 30 unembalmed subjects were examined by dissection and by histological and immunohistochemical staining. In vivo magnetic resonance imaging studies were also carried out on 10 subjects. RESULTS: The dissection study showed that the antebrachial fascia at the volar aspect of the wrist presents a reinforcement. From a histological point of view, it is composed of 3 layers of undulated collagen fiber bundles. Adjacent layers show different orientations of the collagen fibers. Many nerve fibers and Pacini and Ruffini corpuscles were found in all specimens. Under this fibrous plane is another fibrous structure, placed transversely between the ulnar-sided hamate and pisiform bones, and the radial-sided scaphoid and trapezium bones. The deeper fibrous structure shows completely different histological characteristics, having parallel, thicker collagen fiber bundles and few nerve fibers. Magnetic resonance images confirm the presence of 2 clearly distinguished fibrous structures in the wrist, the first in continuity with the antebrachial fascia and the second located in a deeper plane between the hamate and scaphoid. CONCLUSIONS: Two different fibrous structures with different histological characteristics are present in the volar wrist: the more superficial one is in continuity with the antebrachial fascia and could be considered its reinforcement; the deeper one is composed of strong lamina, with histological features similar to those of a ligament. For these reasons, we suggest that the term transverse carpal ligament should be used to indicate the fibrous lamina connecting the hamate and pisiform to the scaphoid and trapezium and that the term flexor retinaculum of the wrist should be abandoned because it does not correspond to any specific, autonomous structure.

Surgical anatomy of the axillary nerve and its implication in the transdeltoid approaches to the shoulder.

BACKGROUND: Traumatic and iatrogenic injuries of the axillary nerve (AN) are frequent in clinical practice; nevertheless, its anatomy and its relationships with the transdeltoid approaches to the shoulder are not well documented. MATERIALS AND METHODS: Anatomic study was performed on 16 shoulders of unembalmed cadavers. A proximal humeral internal locking system (PHILOS) plate was placed to simulate the osteosynthesis of a fracture of humeral surgical neck. The relationships between the plate and the nerve were evaluated. Selective dissection of all the nerve branches inside the deltoid muscle was performed. RESULTS: The mean distance between the point where the AN entered into the deltoid muscle and the humeral head was 5.0 cm, and it was 6.8 cm from the acromion. The mean distance between the origins of the anterior and posterior branches of the axillary nerve was 5.4 cm. The mean diameter of the AN was 0.57 cm, the anterior branch diameter was 0.40 cm, of posterior branch diameter was 0.33 cm, and the teres minor branch diameter was 0.24 cm. The application of the PHILOS plate demonstrated that in 100% of cases, the 2 distal holes of the plate of those dedicated to the humeral head coincided with the passage of AN. DISCUSSION: The different patterns of nerve branches inside the deltoid muscle show that the "safe zone" during transdeltoid approaches is the anterior region of the deltoid muscle for a maximum of 6.7 cm from the acromion. In addition, the insertion of the 2 distal screws of those dedicated to humeral head of the plate should be avoided.

Increasing Fat Graft Retention in Irradiated Tissue after Preconditioning with External Volume Expansion.

BACKGROUND: Fat grafting is an adjuvant that may improve the quality of radiation-damaged tissue. However, fat grafting for volume restoration in irradiated sites may be less effective because of a poorly vascularized fibrotic recipient bed. External volume expansion has emerged as a potential technique to prepare the recipient sites for improved survival of grafted fat. The authors previously demonstrated increased vasculature with external volume expansion stimulation of irradiated tissues. The authors now hypothesize that external volume expansion's improvements in recipient-site vascularity will increase the volume retention and quality of fat grafts in fibrotic irradiated sites. METHODS: Athymic mice were irradiated until development of chronic radiation injury. Then, the irradiated site was stimulated by external volume expansion (external volume expansion group), followed by subcutaneous fat grafting. Grafts in an irradiated site without external volume expansion stimulation (irradiated control group) and grafts in a healthy nonirradiated (nonirradiated control group) site were used as controls. All grafts were monitored for 8 weeks and evaluated both histologically and by micro-computed tomography for analysis of volume retention. RESULTS: Hyperspectral imaging confirmed a 25 percent decrease in vascularity of irradiated tissue (irradiated control group) compared with nonirradiated tissue (nonirradiated control group). Grafts in the irradiated control group retained 11 percent less volume than grafts in the nonirradiated control group. The experimental external volume expansion group achieved a 20 percent (p = 0.01) increase in retained graft volume compared with the irradiated control group. CONCLUSIONS: External volume expansion stimulation can mitigate the effects of irradiation at the recipient site and in turn help preserve fat graft volume retention. Possible mechanisms include increased vascularity, adipogenic conversion, and increased compliance of a fibrotic recipient site.

Embryonic stem cell extracts improve wound healing in diabetic mice.

AIMS/HYPOTHESIS: Impaired wound healing significantly impacts morbidity and mortality in diabetic patients, necessitating the development of novel treatments to improve the wound healing process. We here investigated the topical use of acellular embryonic stem cell extracts (EXTs) in wound healing in diabetic db/db mice. METHODS: Wounds were induced in diabetic db/db mice, which were subsequently treated with EXTs, with 3T3 fibroblast cell line protein extracts (3T3XTs) or with saline as a control. Pathology and mechanistic assays were then performed. RESULTS: The in vivo topical administration of EXTs facilitates wound closure, contraction and re-epithelialization. Moreover, EXTs reduced the number of wound-infiltrating CD45+ inflammatory cells and increased the rate of repair and of angiogenesis as compared to controls. Interestingly, the EXT effect was partly enhanced by the use of a collagen-based biocompatible scaffold. In vivo, topical administration of EXTs increased the percentage of regulatory T cells in the wounded tissue, while in vitro EXT treatment reduced T cell-mediated IFN-γ production. Proteomic screening revealed 82 proteins differentially segregating in EXTs as compared to 3T3 extracts, with APEX1 identified as a key player for the observed immunomodulatory effect of EXTs. CONCLUSIONS: EXTs are endowed with immunoregulatory and anti-inflammatory properties; their use improves wound healing in diabetic preclinical models.

The palmaris longus muscle and its relations with the antebrachial fascia and the palmar aponeurosis.

The palmaris longus (PL) is a muscle of the forearm with a long distal tendon that is continuous with the palmar aponeurosis (PA). It is generally assumed that the muscle lies deep to the antebrachial fascia from origin to termination, but a detailed description is lacking. The relationship of the PL tendon with the antebrachial fascia was studied in 30 dissections. The PL was completely absent in six specimens (20%), whereas the PA was identified in all. Average length of the forearm was 25.5 cm (SD: 2.1 cm, range 22-29 cm), overall length of the PL muscle 26.9 cm (SD: 2.6 cm, range 22.5-31.5 cm), muscular belly 13.8 cm (SD: 3.4 cm, range 9.5-23 cm), tendon 13.1 cm (SD: 3.3 cm, range 8-15.5 cm). Proximally, the PL was situated deep to the antebrachial fascia, then in the lower third of the forearm its tendon perforated the antebrachial fascia (at 4.7 +/- 1.7 cm from the bistyloid line) moving to a suprafascial plane, inserting in the PA. The PA could be divided into two layers: the superficial one formed by longitudinal fibers and adherent to the skin, the deep one formed by transverse fibers continuous laterally with the deep fascia of the hand. The PL tendon was found to be in continuity only with the longitudinal fibers of the PA. Based on the anatomical findings, it may be suggested that the superficial part of the PA is situated in the subcutaneous planes of the palm, and that the muscle should be considered as a tensor of the superficial fascial system of the subcutaneous tissue.

Mechanics of crural fascia: from anatomy to constitutive modelling.

Ten dissections of inferior limbs and histological studies were performed to describe the structural conformation of the muscular fascia of the leg (crural fascia) and to propose a constitutive model to be adopted for the analysis of its biomechanical behaviour. The crural fascia had a mean thickness of 924 microm and was composed of three layers (mean thickness 277.6 microm) of parallel, collagen fibre bundles separated by a thin layer of loose connective tissue (mean thickness 43 microm). Only a few elastic fibres were highlighted. The disposition of the collagen fibres gives the crural fascia anisotropic characteristics. In addition, their crimped conformation is the cause of the non-linear elastic behaviour of the tissue. Both these aspects are included in the constitutive model. The constitutive modelling of the crural fascia represents a useful tool to rationally interpret the correlation between functional behaviour and structural conformation.

Surgical Otoplasty: An Evidence-Based Approach to Prominent Ears Correction.

Otoplasty is one of the first procedures learned during residency. A myriad of surgical techniques and nuances exist. Many have merit, some are ineffective, some destructive, and some frankly fanciful. Adopting an effective and safe technique should be based on proven efficacy and effectiveness to avoid early disappointments. We present a review of traditional otoplasty techniques and more recent innovations. Their pros and cons are discussed in view of the relative risks/benefits balance. Recurrence rates are low for most techniques. Some techniques carry a higher risk of significant complications. A ladder approach preferring techniques that minimize cartilage damage appears advisable.

Leeching as Salvage Venous Drainage in Ear Reconstruction: Clinical Case and Review of Literature.

BACKGROUND: Ear avulsion is a rare complication of different traumas, such as car accidents, human or animal bites and stab wounds, and can result in dramatic cosmetic consequences for the patient. Ear replantation, revascularization, and reattachment are the options offering best aesthetic results. But venous outflow insufficiency is responsible for a high rate of failures. Leeching is one the most efficient methods to relieve venous congestion. It has been used as an alternative venous outflow in case of severe impairment of the physiologic one. METHODS: We present a case of successful rescue of a congested reattached ear by leeching after subtotal avulsion, along with a review of the literature on cases of avulsed auricle reconstruction salvaged by hirudotherapy. Data were collected and analyzed to identify a best regimen to deal with venous congestion. RESULTS: More than 130 cases of avulsed auricle savage are described in the literature, in a fourth of which leech therapy was used in the management of venous congestion. DISCUSSION: In case of both venous outflow deficit or absence, leeches are a potentially successful option to correct the congestion while new veins reestablish normal physiology. The need for anticoagulant/antiaggregant therapy, antibiotics, and often blood transfusion are the main pitfalls of leeching. CONCLUSION: Leeches can be considered a salvage method for ear replantation and reattachment in those cases that lack venous outflow in the presence of valid arterial inflow.

Moderate-Intensity Intermittent External Volume Expansion Optimizes the Soft-Tissue Response in a Murine Model.

BACKGROUND: Intermittent external volume expansion using suction enhances the vascular network of soft tissues, possibly increasing fat graft survival. However, the optimal kinetics of application have not been determined. Based on their previous experience, the authors hypothesized that moderate-intensity intermittent external volume expansion application may further enhance both the angiogenic and adipogenic potential. METHODS: Fifty 12-week-old wild-type mice were assigned to five experimental groups (n = 10 per group) and underwent five different intermittent applications of external volume expansion (i.e., single-application control, low-intensity, moderate-intensity, and two groups of high-intensity). Five days after the final stimulation, skin biopsy specimens were obtained from stimulated and contralateral nonstimulated areas. Microscopic sections were analyzed for angiogenesis, skin remodeling, and adipogenesis. RESULTS: Moderate-intensity intermittent stimulation (0.5 hour, 6 times/day for 5 days at -25 mmHg suction) almost doubled cutaneous vascular density (1.9-fold increase), induced skin thickening (1.9-fold increase), and expanded the subcutaneous tissue (2.3-fold increase) compared with control. External volume expansion kinetics did not affect tissue inflammation at 5 days after treatment. High-intensity intermittent stimulations also increased the density of blood vessels (1.6-fold increase compared with controls) but caused tissue damage, whereas low-intensity external volume expansion did not induce significant changes. CONCLUSION: Application of moderate-intensity intermittent external volume expansion optimizes induction of angiogenesis and adipogenesis in soft tissues without tissue damage, holding potential for time-effective recipient-site preconditioning before fat grafting.