Efficient Decellularization of the Full-Thickness Rat-Derived Abdominal Wall to Produce Acellular Biologic Scaffolds for Tissue Reconstruction: Promising Evidence Acquired from In Vitro Results.

BACKGROUND: Functional restoration of abdominal wall defects represents one of the fundamental challenges of reconstructive surgery. Synthetic grafts or crosslinked animal-derived biological grafts are characterized by significant adverse reactions, which are mostly observed after their implantation. The aim of this study was to evaluate the efficacy of the decellularization protocol to produce a completely acellular full-thickness abdominal wall scaffold. METHODS: Full-thickness abdominal wall samples were harvested from Wistar rats and submitted to a three-cycle decellularization process. Histological, biochemical, and DNA quantification analyses were applied to evaluate the effect of the decellularization protocol. Mechanical testing and immunogenicity assessment were also performed. RESULTS: Histological, biochemical, and DNA analysis results showed efficient decellularization of the abdominal wall samples after the third cycle. Decellularized abdominal wall scaffolds were characterized by good biochemical and mechanical properties. CONCLUSION: The data presented herein confirm the effective production of a rat-derived full-thickness abdominal wall scaffold. Expanding this approach will allow the exploitation of the capacity of the proposed decellularization protocol in producing acellular abdominal wall scaffolds from larger animal models or human cadaveric donors. In this way, the utility of biological scaffolds with preserved in vivo remodeling properties may be one step closer to its application in clinical studies.

The Bridged Digital Artery Perforator Flap as an Alternative Reconstructive Option for Dorsal Digital or Toe Soft Tissue Defects.

BACKGROUND: Dorsal digital soft tissue defects are considered among the most challenging to reconstruct. Numerous treatment options are proposed, including advancement flaps, antegrade, retrograde flow flaps, adipofascial flaps, and digital artery perforator flaps. However, the optimal treatment remains controversial. The concept of the "bridge principle," consisting of the indirect transfer of the flap to the defect area through a muscular bridge, has recently introduced by authors for medial canthal reconstruction. The aim of the study was to examine the feasibility of its application in digital reconstruction for dorsal defects and the development of a new flap. The utilization of the dorsal subcutaneous adipofascial digital or toe tissue as a "bridge" led to description and development of bridged digital artery perforator flaps as an alternative treatment of such defects. METHODS: From November 2017 to September 2019, a series of 14 patients (mean age of 57.1 years) suffered from dorsal digital or toe soft tissue defects of different dimensions and sustained reconstruction with this new technique. RESULTS: Twelve digits and 2 toes have been concerned. The mean size of the defects was 1.3 × 1.1 cm. All flaps survived without a sign of venous congestion. No functional digital or toe problems were observed during the follow-up period (mean of 11.6 months). Minor wound dehiscence presented in 2 cases (2 of 14 [14.3%]) and a transient skin swelling around the flap in 1. CONCLUSIONS: A new concept was introduced to resolve a challenging problem. Initial outcomes are very encouraging. These flaps could be a valuable and reliable reconstructive option.

Tracking the risk factors associated with high-risk cSCC: A 10-year, Two-Institution, Greek study.

PURPOSE: We sought to identify independent risk factors for positive sentinel lymph node biopsy (SLNB), local recurrence (LR), metastasis (M) and death caused by cutaneous squamous cell carcinoma (cSCC) (DCS) in high-risk cSCC patients. Moreover, we compared the Brigham and Women's Hospital (BWH) system with the previous used in Greece (based on tumor size) and proposed a new classification system. METHODS: 1,524 cSCC patients were enrolled between January 2004 and December 2014, from two medical institutions. Potential risk factors for SLNB (local recurrence/LR, metastasis/M, death caused by SCC/DCS) were analyzed by univariate and multivariate Cox logistic regression models. RESULTS: Of the included patients with a median follow-up of 60 months 107 developed local recurrence (7%) while 84 developed metastases (5.5%). Among 36 patients undergoing sentinel lymph node biopsy (SLNB), 25% showed a positive SLNB with a false-negative result (11%). On multivariate analysis, key prognostic factors for LR were tumor diameter ≥2 cm, poor differentiation, incomplete excision and perineural invasion and for M were high-risk tumor site, tumor diameter ≥2 cm, poor differentiation, invasion beyond subcutaneous tissue, incomplete excision, perineural invasion and recurrence. DCS seems to be affected by tumor diameter ≥ 2 cm, poor differentiation, invasion beyond subcutaneous tissue, incomplete excision, perineural invasion and recurrence independently. CONCLUSIONS: These suggest the determined role of tumor diameter of cSCCs. Harnessing knowledge and collecting the up-to-date data along the clinical journey of high-risk cSCC, the future looks bright (development of new clinical trials, adjuvant therapies and tumor staging with SLNB).

Keystone Flaps: Physiology, Types, and Clinical Applications.

The keystone perforator flap (KPF) was first introduced in 2003 by Behan et al for use in reconstruction after skin cancer excision. Since its initial description, KPF use has been expanded to complex defects of various etiologies and disorders throughout the body. At its most basic, the KPF is a perforator-type flap designed with a 1:1 flap-to-defect width ratio. Keystone perforator flaps are specifically raised on pedicles arising from musculocutaneous or fasciocutaneous perforator vessels. Major advantages of the KPF derive from the maintenance of perforator vascular territories, perforosomes, permitting increased flap viability. In turn, this allows for more aggressive undermining in sites away from perforators when greater skin mobilization is necessary. Furthermore, the KPF is relatively easy to perform leading to shorter operative times and no postoperative monitoring period. There are basically 4 different types of keystone flaps in order of increasing undermining and disturbance of underlying fascia. These different classifications of KPFs may be used in different anatomical locations over the entire body based on skin laxity and defect size/depth. Numerous advancements and modifications have been documented adapting the KPF to specific conditions, including myelomeningoceles, and scrotal and lower eyelid defects. The purpose of this article is to provide an organized review of the KPF with emphasis on different classifications, applications, and limitations as well as an overview of the surgical technique. We have additionally included a discussion on KPF physiology and review of current literature.

Changing the Paradigm in Medial Canthal Reconstruction: The Bridge Principle and the Croissant-Like Keystone Island Perforator Flap as An Alternative for Medium Size Soft Tissue Defects in Internal Canthus Reconstruction.

INTRODUCTION: Medial canthus is a common area of skin cancer prevalence. Defects in this region represent a challenging reconstructive task. The nasal version of keystone perforator island flap (KPIF) has proven its versatility. The aim of the present study was to expand its utilization in the neighbor medial canthus area. A modified croissant-like KPIF (CKPIF) was used resolving inner convexity-related problems. The presence of procerus in the glabella area, bridging a surface from nasalis up to the frontalis, changed the traditional dissecting flap technique. Thus, the authors introduce the bridge principle, which consists of the indirect transfer of the flap to the defect site through a muscular "bridge" (the procerus). The authors report their experience in medial canthal reconstruction combining a modified KPIF with a new dissecting "principle." METHODS: From November 2016 to July 2017, a series of patients presenting soft tissue defects of various dimensions in the medial canthus, secondary to tumor extirpation, sustained reconstruction with a CKPIF dissected with the bridge principle. RESULTS: A total of 15 patients were treated with this new technique. Their mean age was 75.3 years. The mean size of the defect was 2.08 cm (length) × 1.5 cm (width). All flaps survived without any sign of venous congestion. A transient epiphora presented in 4 patients (4/15 or 26.6%), which was subsided 2 months later. CONCLUSION: A new approach following a novel paradigm was introduced to resolve an old problem. Initial outcomes are encouraging. However, longer series are needed to extract definitive and safer conclusion.

The Surgical Management of Nerve Gaps: Present and Future.

Peripheral nerve injuries can result in significant morbidity, including motor and/or sensory loss, which can affect significantly the life of the patient. Nowadays, the gold standard for the treatment of nerve section is end-to-end neurorrhaphy. Unfortunately, in some cases, there is segmental loss of the nerve trunk. Nerve mobilization allows primary repair of the sectioned nerve by end-to-end neurorrhaphy if the gap is less than 1 cm. When the nerve gap exceeds 1 cm, autologous nerve grafting is the gold standard of treatment. To overcome the limited availability and the donor site morbidity, other techniques have been used: vascularized nerve grafts, cellular and acellular allografts, nerve conduits, nerve transfers, and end-to-side neurorrhaphy. The purpose of this review is to present an overview of the literature on the applications of these techniques in peripheral nerve repair. Furthermore, preoperative evaluation, timing of repair, and future perspectives are also discussed.

Predictable Pattern Digital Artery Perforator Flap: An Alternative Concept in Digital Reconstruction.

BACKGROUND: The proper digital arteries as any other axial vessel give rise to multiple cutaneous perforators either volar or dorsal along their course. Their identification is performed with Doppler flowmetry. The vasculo-cutano-tendino-osseous complex (VCTOC), which was described by the senior authors, was responsible for the vascularization of all digital anatomic structures (extensor apparatus, skin, periosteum). Their consistent appearance to well measured distances from the digital joints led the way to the present clinical study for highlighting this described anatomy in-vivo and demonstrating the predictability in digital artery perforator (DAP) flap harvest. METHODS: From November 2012 to March 2014, fifteen patients underwent reconstruction with a predictable pattern digital artery perforator flap (PPDAP), based on the previously described VCTOC mapping, for digital lesions secondary to tumor extirpation. Flaps were designed as V-Y advancement or propeller type. Postoperative control concerned flap viability and digital function. RESULTS: Seven males and 8 females underwent elective surgery using PPDAP flaps for digital defects following tumor extirpation. The diameter of the defect ranged from 0.5 to 1.5 cm. The vast majority of the lesions were identified on the right hand, the index, the ring finger and the distal phalanx. All flaps survived without signs of venous congestion. No functional digital problems were observed during follow up (mean of 77 months). A minor wound dehiscence presented in one patient. CONCLUSIONS: Authors introduced the concept of a "predictable pattern" in the surgery of perforator flaps in the digits. These flaps are reliable and could be a valuable reconstructive option.

Keystone Perforator Island Flap as an Alternative Reconstructive Option for Partial Thickness Alar Defects Up to 1.5 Centimeters.

INTRODUCTION: The ala is a unique landmark of the nose disposing aesthetic and functional properties. The head and neck area is the main site of appearance of nonmelanoma skin cancer. One third of them are located in the nose with an alar preponderance compared with other nasal subunits. Correction of alar defects is a challenging reconstructive task. The keystone perforator island flap (KPIF) was introduced as an alternative in nasal reconstruction by senior authors. In the present case series, KPIFs' application is introduced into the alar subunit as an alternative, versatile, and reproducible reconstructive option, even for the novice plastic surgeon. MATERIALS AND METHODS: From April 2014 to September 2015, patients presenting with partial thickness alar defects (≤1.5 cm) secondary to tumor extirpation sustained reconstruction with different types of KPIF. RESULTS: A total of 31 patients (mean age of 72 years) were treated with various types of KPIF. The mean diameter of the defect was 1.14 cm. The vast majority of reconstructions concerned a type IV KPIF (18/31 or 58.1%). Sometimes an upward alar retraction was noted. A minimal rim wedge excision was performed (≤0.3 mm) using counterbalancing correcting sutures. All flaps survived without any sign of venous congestion, whereas the rim healed uneventfully. The mean follow-up period was 6.5 months. CONCLUSIONS: KPIF was introduced as a single-stage alternative reconstructive option for partial thickness alar defects, completing author's experience with this flap into such a challenging and aesthetically critical anatomic area.

Redefining Vascular Anatomy of Posterior Tibial Artery Perforators: A Cadaveric Study and Review of the Literature.

INTRODUCTION: Perforator flaps whether in a free or pedicled form are essential in leg reconstruction, requiring meticulous dissection based on a detailed understanding of vascular topographic anatomy. Numerous investigators have addressed this issue. However, the directionality of their fascial exit has not been greatly discussed in the literature. Subfascial course of the perforating vessel is a crucial determinant for optimal perforator selection especially when the propeller perforator flap option is considered, because an angulated fascial penetration would eventually result in perforator kinking which would additionally compromise vascular patency. The aim of the current study was to investigate the vascular anatomy of posterior tibial artery evaluating a wide range of parameters, including perforators' subfascial directionality, to precisely determine constant reliable perforator sites, in relation to surface landmarks on the medial aspect of the lower leg. MATERIAL AND METHODS: Dissections in 30 lower legs from 25 fresh cadavers were performed. The lower leg was divided into 3 equal vascular zones. Measurements were taken in reference to anatomical landmarks. Perforator clusters to 5-cm intervals from medial malleolus were recorded and analyzed. Vessels with external diameter less than 0.5 mm were excluded. Data regarding the number, distribution, type, external diameter, length from posterior tibial artery, distance, and subfascial directionality were collected and treated. RESULTS: A total of 155 perforators were identified (average number, 5 per leg; average diameter, 1.0 mm). Septocutaneous (127/155) perforators predominated, followed by musculocutaneous (19/155) and septomusculocutaneous (9/155). Most was concentrated in the middle (73/155) and distal (64/155) tertile. There were no septomusculocutaneous perforators at the distal third of the leg, whereas septocutaneous perforators were encountered into all vascular tertiles. An average of 2 comitant veins accompanied each perforator. Length and diameter related to the perforators' location. There was a significant association between perforator length and type. Cluster analysis revealed that reliable perforators were identified within the 21 to 25, 26 to 30, and 16 to 20 cm intervals. CONCLUSIONS: Clinically optimal perforators for the first time were precisely located in relation to subfascial directionality, vascular diameter, and length from the source artery. Continuous improving details of vascular anatomy will further evolve perforator flaps' applications.

The Keystone Perforator Island Flap in Nasal Reconstruction: An Alternative Reconstructive Option for Soft Tissue Defects up to 2 cm.

The aim of this study was to present our experience with the use of the Keystone Perforator Island Flap (KPIF) in a case series of patients with small size (diameter ≤ 2 cm) nasal defects which will be useful prospectively to assist plastic surgeons in planning a reconstructive strategy that will work. The KPIF was utilized in 30 patients with nasal defects post tumor extirpation. More than one type of KPIF (type I or type III) was used following the nasal subunit principle or a modified version of it. The mean follow-up period was 10.5 months. Overall good outcomes were achieved, with no major complications encountered, except minor wound dehiscence in 3 cases. It is the first time that the utilization of this flap is reported in nasal reconstruction. The versatility of the KPIF makes it a safe technique even in the hands of inexperienced surgeons under guidance for nasal defects up to 2 cm in diameter.