The Effects of Negative Pressure by External Tissue Expansion Device on Epithelial Cell Proliferation, Neo-Vascularization and Hair Growth in a Porcine Model

The Effect of Negative Pressure on Wound Healing and Regeneration in Closed Incisions under High Tension: Evidence from Animal Studies and Clinical Experience

Closed-incision negative-pressure wound therapy (iNPWT) is known to enhance wound healing and tissue regeneration. The main aim of the present study is to investigate its effectiveness on enhancing wound healing under tension. An animal study was designed using a swine model by removing a skin flap to create a wound that could be closed primarily under tension, and iNPWT was applied. The enhancement of angiogenesis, lymphangiogenesis, collagen deposition, and tissue proliferation with reduced inflammation by iNPWT was confirmed by histology. The effect of iNPWT was further verified in patients receiving a profunda artery perforator (PAP) free flap for breast reconstruction. iNPWT was applied on the transversely designed donor site in continuous mode for 7 days, in which the wound was always closed under tension. A significant improvement in off-bed time was noted with the application of iNPWT (4.6 ± 1.1st and 5.5 ± 0.8th postoperative days in the iNPWT and control groups, respectively, p = 0.028). The control group (without iNPWT treatment) presented more cases of poor wound healing in the acute (23.1% vs. 0%) and wound breakdown in the late (23.1% vs. 8.3%) stages. The treatment of closed incisions under tension with iNPWT clinically enhances wound healing and tissue regeneration and with histological evidence.

Efficacy and safety of external tissue expansion technique in the treatment of soft tissue defects: a systematic review and meta-analysis of outcomes and complication rates

Background

Currently, various external tissue expansion devices are becoming widely used. Considering the scarcity of relevant application standards, this systematic review was performed to explore the effectiveness and safety of external tissue expansion techniques for the reconstruction of soft tissue defects.

Method

A systematic review and meta-analysis on the efficacy and safety of external tissue expansion technique was conducted. A comprehensive search was performed in the following electronic databases: PubMed/Medline, Embase, Cochrane Library (Wiley Online Library), and Web of Science. Studies reporting patients with soft tissue defects under the treatment of external tissue expansion technique were included.

Results

A total of 66 studies with 22 different types of external tissue expansion devices met the inclusion criteria. We performed a descriptive analysis of different kinds of devices. A single-arm meta-analysis was performed to evaluate the efficacy and safety of the external tissue expansion technique for different aetiologies. The pooled mean wound healing time among patients with defects after fasciotomy was 10.548 days [95% confidence interval (CI) = 5.796-15.299]. The pooled median wound healing times of patients with defects after excisional surgery, trauma, chronic ulcers and abdominal defects were 11.218 days (95% CI = 6.183-16.253), 11.561 days (95% CI = 7.062-16.060), 15.956 days (95% CI = 11.916-19.996) and 12.853 days (95% CI=9.444-16.227), respectively. The pooled wound healing rates of patients with defects after fasciotomy, excisional surgery, trauma, chronic ulcers and abdominal defects were 93.8% (95% CI=87.1-98.2%), 97.2% (95%CI=92.2-99.7%), 97.0% (95%CI=91.2-99.8%), 99.5% (95%CI=97.6-100%), and 96.8% (95%CI=79.2-100%), respectively. We performed a subgroup analysis in patients with diabetic ulcers and open abdominal wounds. The pooled median wound healing time of patients with diabetic ulcers was 11.730 days (95% CI = 10.334-13.125). The pooled median wound healing time of patients with open abdomen defects was 48.810 days (95% CI = 35.557-62.063) and the pooled successful healing rate was 68.8% (95% CI = 45.9-88.1%). A total of 1686 patients were included, 265 (15.7%) of whom experienced complications. The most common complication was dehiscence (n = 53, 3.14%).

Conclusions

Our systematic review is the first to demonstrate the efficacy and safety of external tissue expansion in the management of soft tissue defects. However, we must interpret the meta-analysis results with caution considering the limitations of this review. Large-scale randomized controlled trials and long-term follow-up studies are still needed to confirm the effectiveness and evaluate the quality of healing.

Dual growth factor entrapped nanoparticle enriched alginate wafer-based delivery system for suppurating wounds

We have investigated the wound healing efficiency of calcium alginate wafer embedded with growth factor entrapped PLGA nanoparticle. Herein, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) entrapped PLGA nanoparticles were synthesized and embedded in a sodium alginate gel by freeze-drying technique. The synthesized dressing exhibited a high degree of swelling and appropriate porosity. The scaffold was characterized by Scanning Electron Microscopy (SEM) showing a highly porous morphology. Also, incorporation of growth factor loaded nanoparticles in a wafer-based delivery system resulted in localized growth factor delivery at the site of the wound in a sustained manner. The biocompatibility of the scaffold was evaluated by MTT assay, which showed a higher cell proliferation in the proposed scaffold as compared to the control. In vivo wound healing efficiency of the scaffold was evaluated using a full thickness murine wound model, which showed improved re-epithelialization, collagen deposition, and angiogenesis. These results suggest the use of the scaffold as a promising wound dressing material.

Reconstruction of Large Cervicofacial Defects With Expanded Island Superficial Temporal Artery Flaps and an 810-nm Diode Laser Hair Removal Technique

BACKGROUND

Extensive cervicofacial reconstruction is challenging for plastic surgeons. Because of the location of the adjacent scalp flap nourished by the superficial temporal artery (STA), it can be a candidate for cervicofacial reconstruction.

OBJECTIVES

This article aims to report a combined treatment of an expanded island STA flap and an 810-nm diode laser hair removal technique for extensive cervicofacial defects.

METHODS

Between January 2015 and December 2018, 10 patients with lower face and neck scar contraction were reconstructed with a bilateral or unilateral expanded STA island flap and an 810-nm diode laser for hair removal in this retrospective study. Hair removal via the 810-nm laser was started when the injected volume reached the volume of the expander, with a fluence of 35 to 40 J/cm2 and a 1 to 2 Hz repetition rate. Before second-stage surgery, the hair reduction rate was assessed. Twelve months after surgery, the degree of epilation efficacy according to the satisfaction scale and Global Aesthetic Improvement Scale was evaluated.

RESULTS

This study included 2 single-pedicle flaps and 8 double-pedicle flaps. The average size of the implanted expanders was 600 mL. The average injected volume was 1405 mL. Before second surgery, there was a 67.4% hair reduction rate. Twelve months after surgery, the results of Global Aesthetic Improvement Scale were very good (3), good (6), average (1), and poor (0).

CONCLUSIONS

The expanded island STA flap and 810-nm diode laser technique may be a novel treatment option for severe face and neck aesthetic reconstruction.

Mechanotransduction in Wound Healing: From the Cellular and Molecular Level to the Clinic

GENERAL PURPOSE

To review the various mechanical forces that affect fibroblasts, keratinocytes, endothelial cells, and adipocytes at the cellular and molecular level as well as scar-reducing mechanical devices currently in clinical use.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will:1. Compare and contrast the responses of various types of cells to mechanical forces.2. Identify the mechanical devices and techniques that can help restore skin integrity.

Multidisciplinary Application of an External Tissue Expander Device to Improve Patient Outcomes: A Critical Review

Significance: Continuous external tissue expansion (CETE) is a versatile tool in soft tissue injury management, and could be an addition to the traditional reconstructive ladder.

Recent Advances: This critical review discusses the principles and application of CETE, covering a company-sponsored consensus meeting on this emerging technology and highlighting the DermaClose^® (Synovis Micro Companies Alliance, Inc., Birmingham, AL) device's unique approach to soft tissue injury management. There is clinical evidence to support the use of CETE in the management of a number of wound types, including fasciotomy, trauma, amputation, and flap donor sites. The device can be applied to open wounds, potentially avoiding the need for a skin graft or other more complex or invasive reconstruction options. DermaClose applies constant tension without restricting blood flow and does not require repeated tightening.

Critical Issues: CETE is becoming more widely used by surgeons of different specialties, and numerous reports describing its efficacy and safety in wound management have been published. Surgeons using CETE must follow the correct technique and select patients carefully to achieve optimal outcomes. However, there is no single source of information or consensus recommendations regarding CETE application.

Future Directions: Prospective evidence on the efficacy and safety of CETE in clinical practice is required to communicate the best techniques and share important experiences. This will help to solidify its place in the reconstructive ladder as a valuable additional option for surgeons.

Negative Pressure From an Internal Spiral Tissue Expander Generates New Subcutaneous Adipose Tissue in an In Vivo Animal Model

BACKGROUND

Tissue expanders are widely utilized in plastic surgery. Traditional expanders usually are "inflatable balloons," which are planned to grow additional skin and/or to create space to be filled, for example, with an implant. In very recent years, reports suggest that negative pressure created by an external device (ie, Brava) induces both skin expansion and adipogenesis.

OBJECTIVES

The authors evaluated and assessed the adipogenetic potential of a novel internal tissue expander in an in vivo animal model.

METHODS

New Zealand female rabbits were enrolled in the study. A prototype spiral inner tissue expander was employed. It consisted of a-dynamic conic expander (DCE) with a valve at the end: when empty, it is flat (Archimedean spiral), whereas when filled with a fluid, it takes a conic shape. Inside the conic spiral, a negative pressure is therefore created. DCE is implanted flat under the latissimus dorsi muscle in experimental animals (rabbit) and then filled to reach the conical shape. Animals were investigated with magnetic resonance imaging, histology, and transmission electronic microscopy at 3, 6, and 12 months.

RESULTS

Magnetic resonance imaging revealed a marked increase in newly formed adipose tissue, reaching its highest amount at 12 months after the DCE implantation. Histology confirmed the existence of new adipocytes, whereas transmission electronic microscopy ultrastructure confirmed that most of these new cells were mature adipocytes.

CONCLUSIONS

Tensile stress, associated with negative-pressure expanders, generated newly white subcutaneous adipose tissue.

The Preparation of the Recipient Site in Fat Grafting: A Comprehensive Review of the Preclinical Evidence

BACKGROUND

Several methods to prepare the recipient site in fat grafting have been proposed in recent decades. However, to date, these procedures have never been reviewed exhaustively. The purpose of the present study is to provide a comprehensive overview of the different techniques to prepare the recipient site for fat grafting as they were investigated in preclinical studies, with resulting outcomes and underlying mechanisms of action.

METHODS

The PubMed/MEDLINE database was queried to search for preclinical investigations on the preparation of the recipient site in fat grafting using the following algorithm: ((recipient site) AND (fat grafting) OR (lipofilling) OR (lipograft)). A priori criteria were applied to review the resulting articles.

RESULTS

Thirteen animal studies met inclusion criteria. Overall, five techniques were identified: external volume expansion, implantation of alloplastic material (silicone sheets), administration of cell-proliferation factors (i.e., vascular endothelial growth factor, adipose tissue-derived stromal vascular fraction, and interleukin-8), ischemia, and microneedling. A positive effect on cellular activity (cell proliferation and angiogenesis) was demonstrated by all studies and achieved with all techniques. Seven of the eight authors who examined this aspect reported enhancement of fat graft survival.

CONCLUSIONS

Improvement of fat grafting surgical outcomes is documented preclinically using different recipient-site preparation techniques, particularly through enhancement of vascularization and soft-tissue expansion. This understanding will lead to further clinical research, especially for those cases where improvement of the recipient site is recommended, such as contracted scars or preirradiated tissues.

The Impact of Recipient Site External Expansion in Fat Grafting Surgical Outcomes

BACKGROUND

The fat grafting process includes the 4 phases of tissue harvesting, processing, recipient-site preparation, and reinjection. Among them, the preparation of the recipient site has never been exhaustively reviewed. We aim to provide a comprehensive overview of the methods to prepare the recipient site through external expansion with the resulting outcomes.

METHODS

PubMed/Medline database was searched for studies on fat grafting recipient site preparation by applying the following algorithm: ((fat grafting) OR (lipofilling) OR (lipograft) AND (recipient site)). A priori criteria were used to review the resulting articles and identify those dealing with external expansion.

RESULTS

Fourteen studies published from 2008 through 2016 met inclusion criteria (4 case reports, 6 retrospective, and 4 prospective studies), representing 1,274 treated patients. Two devices for preexpansion were used with different protocols: BRAVA system and Kiwi VAC-6000M with a PalmPump. The 13 studies that applied the BRAVA system reported large fat volume transplantation to the breast (average > 200 cc). The most common complications were localized edema (14.2%), temporary bruising, and superficial skin blisters (11.3%), while the most serious was pneumothorax (0.5%). The majority of the studies reported enhancement of fat graft survival, which ranged between 53% and 82% at 6 months to 1 year follow-up, and high satisfaction of patients and surgeon.

CONCLUSIONS

External expansion and fat grafting is a promising technique for breast reconstruction and augmentation. However, due to the overall low level of evidence of the available studies, further research is needed to validate the procedure.