True and 'choke' anastomoses between perforator angiosomes: part i. anatomical location

Angiosome-Guided Perfusion Decellularization of Fasciocutaneous Flaps

BACKGROUND

 Tissue engineering based on whole-organ perfusion decellularization has successfully generated small-animal organs, including the heart and limbs. Herein, we aimed to use angiosome-guided perfusion decellularization to develop an acellular fasciocutaneous flap matrix with an intact vascular network.

METHODS

 Abdominal flaps of rats were harvested, and the vascular pedicle (iliac artery and vein) was dissected and injected with methylene blue to identify the angiosome region and determine the flap dimension for harvesting. To decellularize flaps, the iliac artery was perfused sequentially with 1% sodium dodecyl sulfate (SDS), deionized water, and 1% Triton-X100. Gross morphology, histology, and DNA quantity of flaps were then obtained. Flaps were also subjected to glycosaminoglycan (GAG) and hydroxyproline content assays and computed tomography angiography.

RESULTS

 Histological assessment indicated that cellular content was completely removed in all flap layers following a 10-hour perfusion in SDS. DNA quantification confirmed 81% DNA removal. Based on biochemical assays, decellularized flaps had hydroxyproline content comparable with that of native flaps, although significantly fewer GAGs (p = 0.0019). Histology and computed tomography angiography illustrated the integrity and perfusability of the vascular system.

CONCLUSION

 The proposed angiosome-guided perfusion decellularization protocol could effectively remove cellular content from rat fasciocutaneous flaps and preserve the integrity of innate vascular networks.

Extended DIEP flap with bilateral anterior fascia based on unilateral perforator for lower extremity reconstruction

Complex soft tissue defects in the lower limb pose significant challenges for surgeons, especially when extensive coverage is needed. Free flaps are preferred for their reliable soft tissue, with the deep inferior epigastric perforator (DIEP) flap being particularly advantageous in middle-aged women due to its ample tissue and the ability to perform abdominoplasty at the donor site. However, its bulkiness can be an issue for lower limb reconstruction. We present two cases where the DIEP flap was used for lower limb reconstruction with immediate flap thinning. By employing a unique thinning method based on the vascular connection between perforators, we successfully extended the flap's use without needing to anastomose the pedicles. All flaps were well-vascularized with no complications, demonstrating that maintaining the anterior fascia between perforators optimizes the DIEP flap for reconstructive purposes.

Arborization of Musculocutaneous Perforators in the Skin and Subcutaneous Tissue

Background

The arborization of musculocutaneous (MC) perforators in the skin and subcutaneous tissue has been well studied using cadaver anatomical studies and preoperative imaging such as computed tomography and magnetic resonance angiography. However, the fine arborization of perforators and anastomoses between fine vessels in the skin and subcutaneous tissue remains unreported. Understanding the peripheral arborization and characteristics of these vessels is essential for advancing perforator flap techniques. We performed vascular dissection based on the layered structure to examine the vascular network of the subcutaneous tissue.

Methods

In 8 fresh cadavers, the buttocks (single layer of subcutaneous fat) and back (double layer) were examined through radiological and gross observations of MC perforators, with the fine arterial architecture analyzed in relation to the layered structure of the subcutaneous tissue.

Results

Thin blood vessels at the periphery of the MC perforator were visualized. The perforator reached the dermis, forming a subdermal plexus, from which twigs ascended to the epidermis and descended to the subcutaneous fat. The vascular plexus in subcutaneous tissue varied with the adipofascial structure, and twigs connecting the subdermal plexus to deep adipose tissue were also observed.

Conclusions

The thinning of perforator flaps and the elevation of adipofascial flaps depend on the judgment of clinicians. We believe that understanding the arborization and vasculature of MC perforators will enhance perforator flap procedures, ensuring safer and stable blood flow.

Arteriogenesis Mechanism in Remodeling of Choke Vessels Within Choke Zone 2 of Delayed Multiterritory Perforator Flap

BACKGROUND

The aim of this study is to validate that both morphological and hemodynamic changes in the choke vessels remodeling within the choke zone 2 of delayed multiterritory perforator flap (MPF) in rats are consistent with revascularization through the arteriogenesis mechanism.

METHODS

Two hundred seventy-two Sprague-Dawley (SD) rats were randomly divided into 4 groups: group A (classical group with harvested MPF), group B (delay group with ligated perforator in the potential region), group C (delay group with ligated perforator in the dynamic region), and group D (delay group with double fasciocutanoeus pedicles). The morphological changes in the choke vessels were evaluated using integument radiography and H&E staining, while the hemodynamic alterations within the choke zones were assessed utilizing a laser Doppler blood flow imager.

RESULTS

In choke zone 2, the true anastomosis emerged on 5 days postoperatively, and 3, 3, and 5 days after the delay surgery in group A, B, C, and D, respectively. The microvessel densities on each time points postoperatively were lower than those before operation in the 4 groups (P > 0.05). The arteriolar diameters on 5 days after the delay surgery were significantly larger than those before operation in group B, group C, and group D (P < 0.05). In the group B, C, and D, the blood perfusion at 1 day after the delay surgery was significantly higher than that at 6 hours after the delay surgery (P < 0.05).

CONCLUSIONS

The arteriogenesis mechanism plays an important role in the remodeling of the choke vessels in the choke zone 2 within the MPF after 3 types of delay procedures.

Finding Perforator "Freeway" for Design Optimization of Expanded Flaps by Indocyanine Green Angiography

SUMMARY

Indocyanine green angiography (ICGA) is a useful tool for the visual assessment of superficial blood flow. The authors used ICGA to visualize perforator branches and linking vessels to provide a road map for flap design of an expanded flap. Twenty-eight expansions were planned to use the back-cut technique in 26 patients. ICGA was used to visualize the perforator branching pattern with the linking vessels and the venous network in the expanded flap before expander explantation. The appropriate perforator was selected, and the flap was designed following the axiality of its branch linked by true anastomoses. The vein running closely was chosen as the axial vein. The back cut was designed to avoid transection of the axial artery and vein. Patient characteristics, defect characteristics, and reconstructive outcomes were assessed. ICGA clearly visualized the perforator branches and the linking vessels in the expanded flap at 4the head and neck, trunk, and extremity. The back-cut flap containing the axial artery and vein was raised successfully in 27 expansions. The arterial perforator and superficial vein separated greatly and resulted in design modification from back-cut to advancement flap in one expansion. All expanded flaps met the reconstructive needs and exhibited complete survival. ICGA allowed the visualization of the preoperative topography of the vascular network in the expanded flap and helped surgeons locate the vascular axis and perform an appropriate back-cut design for efficient and safe flap transfer.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Choke Anastomosis: A Key Element Acting as a Shunt Converter Between Adjacent Angiosomes

BACKGROUND

Choke anastomosis is commonly recognized as a resistance factor that detrimentally affects the hemodynamics of the skin flap; however, its additional potential physiological roles in normal skin function are currently not fully understood.

METHODS

Ten cadaveric forehead flap specimens pedicled with unilateral STAs were perfused with lead oxide-gelatin mixture, and then dissected into 3 layers, including the super temporal fascia-frontalis-galea aponeurotica layer, the subcutaneous adipose tissue layer, and the "super-thin flap" layer. The forehead flap and stratified specimens underwent molybdenum target x-ray and subsequent transparent processing to effectively visualize the microscopic spatial architecture of arterial vessels across all levels.

RESULTS

Based on the different anastomoses near the midline area of the flap, 2 types of arterial perfusion were identified: choke anastomosis type (8/10) and true anastomosis type (2/10). The former formed multiple choke anastomoses near the midline. In the "super-thin flap" layer, arterial perfusion density on the ipsilateral side was significantly higher compared to that on the contralateral side. The arterioles on the ipsilateral side exhibited a dense and uninterrupted distribution, whereas those on the contralateral side appeared sparse and dispersed. The latter exhibited an alternative perfusion pattern; the bilateral arterial vessels were connected with 3 to 5 true anastomoses near the midline. Furthermore, the microscopic architecture confirmed a uniform distribution of arterioles that remained continuous from ipsilateral to contralateral sides in the "super-thin flap" layer.

CONCLUSION

This study demonstrated that choke anastomosis not only impairs blood perfusion in the adjacent angiosomes but also acts as a shunt converter to impact the blood supply of distal skin flaps at different levels through the "trans-territory diversion phenomenon." This results in necrosis of the superficial dermis while preserving survival of the deep subcutaneous adipose tissue.

Utility of Free Fibula Flap With an Extended Banana-shaped Skin Paddle for Oro-mandibular Reconstructions

The free fibula flap is a common technique for mandibular bone defects. However, its limited skin paddle is disadvantageous in cases with significant soft-tissue defects. A free fibula dual-skin paddle flap is used for medium-sized soft-tissue defects. Just as the anterolateral thigh flap can be extended through linking vessels, so the peroneal skin flap can be extended to the adjacent proximal area through linking vessels. This has led to the development of the free fibula banana-shaped flap. From 2021 to 2023, 8 patients, with an average age of 68.1 years, underwent head and neck reconstructive surgery using the free fibula banana-shaped flap at the Saitama Cancer Center in Japan. Their primary disease, defect sites, flaps, bone size, and postoperative complications were analyzed retrospectively. The blood flow of the flap was examined using intraoperative indocyanine green imaging. All 8 patients had successful operations with only 1 partial necrosis of the flap tip. Four patients had buccal mucosa cancers, 3 had osteoradionecrosis of the jaw, and 1 had lower gingival cancer. The flap size averaged 25.0 ± 3.0 cm (long axis) and 4.1 ± 0.4 cm (short axis), with a transplanted bone length of 8.4 ± 1.9 cm. The number of perforators was 1-3 in the distal to the central area. All flaps' microcirculation was confirmed with intraoperative indocyanine green imaging; the average time was 3 minutes 59 seconds. Postoperative complications included 1 surgical site infection and 1 minor salivary leak. The free fibula banana-shaped flap is a good option for head and neck reconstructive surgery in medium-sized soft-tissue defects with mandibular bone defects.

Imaging Study of Peroneal Artery Branches and its Application in Flap Design and Transplantation

The reconstruction of defects in the lower extremity with bone or tendon exposure presents a significant challenge in clinical practice. Among the various surgical options available, the peroneal artery perforator flap (PAPF) stands out as a superior choice for repairing such defects. However, due to potential damage and variations in the peroneal artery's branches and perforators, identifying these anatomic features accurately is crucial for optimizing flap design and transplantation. This study reports the successful experience of reconstructing soft tissue defects of the lower extremity using PAPF. Preoperative digital subtraction angiography (DSA) was used to visualize the peroneal artery and its branches. High-frequency ultrasound was also employed to accurately locate perforating branches. This approach enables visualization, customization, and precision in flap surgery, assisting in flap design and transplantation.

Prognostic Prediction of Multiterritory Flap: A Preliminary Clinical Study on the Classification of Priority Developing Artery and Arterial Anastomosis Utilizing Indocyanine Green Angiography

BACKGROUND

Congestion and necrosis are frequent complications in multiterritory flaps. Indocyanine green angiography (ICGA) is a commonly utilized tool for evaluating blood flow and perforator location within the flap; however, there is currently no existing research investigating its potential to predict flap prognosis before surgery.

METHODS

The forehead skin of 50 surgical patients was assessed using preoperative ICGA, enabling observation and classification of the priority developing artery and arterial anastomosis among adjacent arterial perfusion territories during the arterial phase. Subsequently, 5 clinical cases of forehead flap transfer were studied to validate the classification method.

RESULTS

First, the priority developing artery can be classified into 4 types and 5 subtypes, encompassing type Ⅰa: Bilateral ST-As equalization type (9/50), type Ⅰb: unilateral ST-A dominance type (11/50), type II: SOT-As dominance type (14/50), type III: unilateral ST-A plus SOT-A dominance type (6/50), and type IV: bilateral ST-As plus SOT-As equilibrium type (10/50). Second, arterial anastomosis can be divided into 5 types: type I: complete choke anastomosis type (13/50), type II: complete true anastomosis type (7/50), type III: central choke anastomosis type (10/50), type IV: bilateral choke anastomosis type (8/50), and type V: unilateral choke anastomosis type (12/50). Finally, the clinical flap outcomes showed that the ICGA classification could serve as a good prognostic indicator.

CONCLUSIONS

The hemodynamic classification of priority developing artery and arterial anastomosis employed by ICGA has the potential to predict flap prognosis and offer valuable insights for preoperative design and perioperative treatment strategies. More sample size is needed to optimize and validate this classification.

Flap Monitoring Techniques: A Review

Postoperative tissue flap vitality monitoring enables early detection of clinical complications, allowing for intervention. Timely re-operation can prevent the need for extensive correction procedures, thus reducing healthcare costs and hospitalization time. Statistics show that monitoring can increase the success rate of flap survival to 95% or higher. However, despite the significant progress in monitoring techniques, major and minor complications, leading to the loss of the flap, still occur. This clinical application review aims to provide a comprehensive overview of the recent advancements and findings in flap surgery reconstructions, transplants, and systems for their postoperative assessment. The literature from the years 1925 to 2024 has been reviewed to capture previous and current solutions for monitoring flap vitality. Clinically acclaimed methods and experimental techniques were classified and reviewed from a technical and clinical standpoint. Physical examination, metabolism change, ultrasound method, and electromagnetic (EM) radiation-based measurement methods were carefully evaluated from the perspective of their considered applications. Guidelines aiding engineers in the future design and development process of monitoring systems were proposed. This paper provides a comprehensive overview of the monitoring techniques used in postoperative flap vitality monitoring. It also gives an overview of each approach and potential ways for future development.

Clinical study on anterolateral femoral interregional flap with turbocharge technique in the repair of large limb wounds

OBJECTIVES

To compare the clinical outcomes of anterolateral femoral interregional flap with turbocharge technique and traditional anterolateral femoral flap in repair of large limb wounds.

METHODS

Clinical data of 38 patients with large limb surface wound (11 cm×39 cm-16 cm×65 cm) admitted to the Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from May 2018 to May 2022 were retrospectively analyzed. Eighteen patients were treated by anterolateral thigh perforator flap combined with superficial circumflex iliac artery flap (ALTP-SCIAP) with turbocharge technique (interregional flap group); while 20 patients were treated with unilateral or bilateral anterolateral femoral flaps, combined with skin grafting if necessary (traditional anterolateral femoral flap group). The survival of skin flap, repair of donor area, complications and patient satisfaction were compared between the two groups.

RESULTS

In interregional flap group, 18 flaps were harvested and transplanted, the flap width, length and the viable area were (9.9±2.0) cm, (44.2±3.5) cm and (343.2±79.9) cm2, respectively. In traditional anterolateral femoral flap group, 29 flaps were harvested and transplanted, the flap width, length and the viable area were (11.0±2.8) cm, (21.7±3.2) cm and (186.4±49.2) cm2, respectively. There were significant differences in the flap length and the viable area between the two groups (t=22.365 and 8.345, both P<0.05). In the interregional flap group, the donor site of flap was closed by direct suture in 11 flaps, by skin retractor assisted suture in 6 flaps, and by skin grafting in one flap. In traditional anterolateral femoral flap group, the donor site of flap was closed by direct suture in 12 flaps, by skin retractor assisted suture in 11 flaps, and by skin grafting in 6 flaps. The skin graft rates of the two groups were 5.6% (1/18) and 20.7% (6/29), respectively (χ2=2.007, P>0.05). The interregional flap group had lower postoperative complications rate (5.6% vs. 35.0%, χ2=4.942, P<0.05) and higher patient satisfaction rate (94.4% vs. 70.0%, χ2=4.448, P<0.05) than traditional anterolateral femoral flap group.

CONCLUSIONS

Compared with the traditional anterolateral femoral flap, the anterolateral femoral interregional flap with turbocharge technique has a larger flap area, most of the donor areas of the flap can be sutured directly without skin grafting and with less complications and a higher patient satisfaction rate.

Modified medial gastrocnemius myocutaneous flap with extended anterior, inferior and/or posterior boundaries: Anatomical observation and report of a clinical series of 33 flaps

INTRODUCTION

Reports on medial gastrocnemius myocutaneous (MGM) flaps with extended inferior and posterior boundaries are rare, and information about the MGM flaps with extended anterior boundaries is unavailable. Thus, this study aimed to investigate the vascular anatomical basis and clinical reliability of the modified MGM flap with extended anterior, inferior and/or posterior boundaries.

METHODS

Five fresh lower limb specimens from patients with recurrent tumours in the thigh were immediately irrigated and perfused. The stripped integuments were radiographed. The pretibial skin was equally divided into nine zones. The reconstruction outcomes of the modified MGM flaps were documented in 33 patients.

RESULTS

True anastomotic connections existed among the branches of the saphenous artery, the perforator from the inferior medial genicular artery and 3-5 (mean, 4.5) perforators from the posterior tibial artery in the upper two-thirds of the leg. A total of 33 modified MGM flaps were applied. The anterior margins of 26 modified flaps with extended anterior boundaries exceeded the medial edge of the tibia by 1.0-4.5 cm (mean, 2.1 cm). Fourteen modified MGM flaps were used to repair the defects involving the lower third leg, whose distal edges were located in the seventh (n = 8) or eighth (n = 6) zone. A 1-169-month (median, 9 months) follow-up was conducted for 33 patients. Of the 33 flaps, 29 (87.9 %) survived completely, partial necrosis occurred in four flaps with extended anterior (n = 2) or inferior (n = 2) boundaries.

CONCLUSIONS

Multiple source vessels are the vascular anatomical basis of the modified MGM flap with extended anterior, posterior and/or inferior boundaries. The modification of the MGM flap is feasible and reliable, broadening the applicable scope of the flap. The modified MGM flap can be applied to repair more distal, wider and larger-area defects with a simpler design and procedure.

Optimizing the Use of Pedicled versus Random Pattern Local Flaps in the Foot and Ankle

Background

The aim of this study was to compare the use of pedicled local (PFs) versus random pattern flaps (RpFs) in foot and ankle reconstruction in patients with chronic, nonhealing wounds.

Methods

A single-center, retrospective review of 204 patients with 118 PFs and 86 RpFs was performed. The primary outcome included rates of limb salvage.

Results

PFs were used more often in the hindfoot (44.1% versus 30.2%, P = 0.045), lateral and medial surface (39.8% versus 18.6%, P = 0.001), and wounds containing exposed bone and hardware (78.8% versus 62.8%, P = 0.018). RpFs were used more for forefoot (19.8% versus 10.2%, P = 0.053) and plantar defects (58.1% versus 30.3%, P = 0.000). RpFs had a higher rate of immediate success (100% versus 95.8%, P = 0.053), with no significant differences in rate of long-term limb salvage (77.1% versus 69.8%, P = 0.237). PFs had higher rates of ischemia requiring intervention (11.0% versus 3.5%, P = 0.048). RpFs had a higher rate of minor amputations (15.12% versus 6.8%, P = 0.053) but similar rates of major amputation (15.1% versus 16.1%, P = 0.848). There were no significant differences in rates of mortality or ambulatory status.

Conclusions

Both RpFs and PFs remain reliable options to reconstruct defects of the foot and ankle. Optimizing the use of each flap type should consider wound characteristics. RpFs are preferred for dorsal and plantar defects, whereas PFs are protective for minor infections and preferred for deeper wounds despite a higher rate of partial necrosis.

Extrinsic Vascular Pathway Preservation Improves Survival in a Rat Three-Territory Flap Model Based on the Deep Circumflex Iliac Artery

BACKGROUND

Extended flaps are commonly applied for large defects. However, a postoperative flap necrosis incidence of 11% to 44% remains a major complication. Previous clinical studies have shown that maintaining the extrinsic vascular pathway (EVP) can increase the survival area of extended flaps. The authors hypothesized that preserving the EVP would improve flap survival by reducing blood resistance within the vascular territory.

METHODS

Twenty-four adult male Sprague-Dawley rats were used. Tissue samples were obtained from eight untreated rats as a baseline control. Three-territory flaps were elevated in the remaining 16 rats. The EVP was preserved or ligated. Flap perfusion was assessed immediately using indocyanine green angiography. Rats were euthanized on day 7. The flap survival area was measured using Adobe Photoshop. Hematoxylin and eosin staining, CD31 immunostaining, and Western blot analysis of vascular endothelial growth factor protein expression were used to quantitatively assess vasodilation and angiogenesis in choke zones.

RESULTS

Indocyanine green angiography revealed that blood could flow through the preserved EVP and perfuse the third vascular territory of the flap. EVP preservation significantly increased flap survival area (86.3%, 19.3% difference; P < 0.001), promoted vasodilation (5.0/choke zone, 3.0/choke zone difference; P = 0.013) and angiogenesis (29.3/mm 2 , 14.3/mm 2 difference; P = 0.002), and increased vascular endothelial growth factor expression (0.6, 0.2 difference; P = 0.067) in the second choke zone.

CONCLUSIONS

EVP preservation improves flap survival in this rat three-territory flap model. Further investigation in large-animal models is required for clinical translation.

CLINICAL RELEVANCE STATEMENT

Although further validation in large animal models and prospective clinical trials are necessary to verify the efficacy of the authors' hypothesis, their findings suggest that the EVP preservation procedure could provide an alternative for surgeons to create an extended flap in defect reconstruction.

High-pressure infusion improves multi-territory perforator flap viability via choke artery dilation: A preliminary study in a rat model

BACKGROUND

Multi-territory perforator flaps have become the preferred option for the repair and reconstruction of large soft tissue defects. Although methods (e.g., pharmacological agents, mechanical stimulation, and thermal stimulation) were developed to open choke vessels to improve flap survival, the flap necrosis rate is still as high as 28.8%. The authors hypothesized that high-pressure infusion might enhance flap viability by dilating choke arteries intraoperatively in a rat model of multi-territory perforator flap.

METHODS

Two-month-old male Sprague-Dawley rats were randomized into two groups (n = 32 each). During the multi-territory perforator flap elevation based on the right superficial epigastric angiosome, one group received continuous high-pressure infusion (mean pressure, 250 mmHg; duration, 1 min) of an isotonic heparin sodium solution (12,500 U/L) via the artery in the pedicle, whereas the other group received no infusion. At 7 days postoperatively, arteriography was performed; endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) expression and microvascular density were evaluated by western blot and histology, respectively; and flap survival was compared. Moreover, intraluminal diameters were examined at 1 day and 7 days postoperatively using hematoxylin and eosin staining, and coagulation function was assessed immediately postoperatively.

RESULTS

High-pressure infusion significantly promoted the dilation of choke arteries at 1 day and 7 days postoperatively. It also increased eNOS and VEGF expression, flap survival, and microvascular density. The coagulation function remained unaffected.

CONCLUSIONS

High-pressure infusion allowed intraoperative and postoperative dilation of the choke arteries that enhanced the viability of multi-territory perforator flaps in rats.

Hemodynamics in Distally Based Sural Flaps for Lower Leg Reconstruction: A Literature Review

Coverage of posttraumatic and chronic wounds at the distal leg is a difficult problem due to limited soft tissue available for local flaps. The sural flap is a versatile and effective method for reconstruction in this area since it does not need a significant amount of time or assistance to complete. Improving the survival of these flaps is critically dependent on understanding the basics of flap circulation and why recent modifications were introduced. This review will serve as a much-needed comprehensive analysis of these topics for surgeons looking to increase the reliability of their sural flaps.

Arterialization of plantar venous system via vein graft: A novel technique for reconstruction of heel pad degloving injuries

BACKGROUND

Patients with heel pad degloving injury frequently develop ischemic necrosis of the area, necessitating soft-tissue reconstruction surgery. We have developed a technique for arterialization of the plantar venous system via vein graft (APV) as the primary revascularization treatment. The objective of this study was to clarify both the utility of APV for the preservation of degloved heel pads and the impact of this preservation on clinical outcomes.

METHODS

Ten consecutive cases of degloving injury with devascularized heel pad were treated at a single trauma center from 2008 to 2018. Five cases underwent APV and five underwent conventional primary suture (PS) as the initial treatment. We evaluated the course according to the frequency of heel pad preservation, additional intervention after heel pad necrosis, post-operative complications, and outcomes using the Foot and Ankle Disability Index score (FADI) at the time of last follow-up.

RESULTS

Among the five cases that underwent APV, the heel pad was preserved in three cases and flap surgery was required in two cases. All cases that underwent PS developed necrosis of the heel pad, requiring skin graft in one case and flap surgery in four. One skin graft case and one free flap case after PS developed plantar ulcers. The three cases with preserved heel pads exhibited higher FADI than the seven cases that developed necrosis.

CONCLUSION

APV showed a relatively high frequency of heel pad preservation, which otherwise was uniformly lacking. Functional outcomes were improved in cases with preserved heel pad compared to those that developed necrosis and underwent additional tissue reconstruction.

Effects of pharmacological delay with roxadustat on multi-territory perforator flap survival in rats

Roxadustat (FG-4592) is a specific hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor. We investigated the effects of FG-4592 pretreatment on survival and second choke vessels of multi-territory perforator flaps in rats. In total, 72 rats were divided into two groups (n = 36 each): the experimental (FG-4592) group and the control group. FG-4592 was administered orally as a single dose of 60 mg/kg every other day; the first drug solution was administered to the animals 7 days before the surgical procedure. On postoperative day 7, the surviving flap area was calculated. At 12 h post-surgery, in the second choke zone in the flaps, macrovascular hinges were compared by angiography and imaging, and microvascular changes were assessed by histology. Laser Doppler imaging was used to evaluate flap perfusion at the second choke zone at 12 h and 7 days after surgery. At 7 days after surgery, the flap survival area and perfusion were significantly greater in rats given FG-4592 compared with controls. At 12 h after surgery, the diameter of macrovascular and microvascular vessels, nitric oxide content, perfusion, and the protein levels of HIF-1α and inducible nitric oxide synthase were also significantly greater in FG-4592-treated rats than controls. In conclusion, pretreatment with roxadustat may improve initial flap survival and dilate the second choke zone vessels in a multi-territory perforator flap.

Revisiting Bipedicled Flaps for Lower Extremity Distal Third Defects

BACKGROUND

Lower extremity reconstruction of the distal third of the leg is challenging. Free tissue transfer is the criterion standard. The COVID-19 pandemic encouraged seeking alternatives for resource consuming procedures. Bipedicled flaps are flaps with a dual-source subdermal perfusion. The purpose of this study was to assess outcomes of patients who had bipedicled flaps primary or auxiliary local flap for distal third leg/foot reconstruction.

METHODS

A retrospective review of patients undergoing lower extremity reconstruction (2020-2021) was performed. Inclusion criteria were patients older than 18 years with lower extremity wounds secondary to traumatic injury for which bipedicled flaps were used in the reconstruction. Exclusion criteria included lower extremity wounds secondary to peripheral vascular disease or diabetes.

RESULTS

Fourteen patients were included in the study. All patients had distal third of the leg/foot wounds, and 12 patients (87.5%) had concurrent leg fractures. In 8 patients (57.1%), the bipedicled flap was used to decrease the wound size and facilitate another concurrent flap: hemisoleus (21.4%), anterior tibialis muscle turnover (14.3%), medial plantar artery (14.3%), and posterior tibial artery perforator (14.3%). Mean wound size for bipedicle flaps used alone was 42.0 ± 18.3 cm2, whereas wounds that required a bipedicled flap with an additional flap were 69.9 ± 80.8 cm2 (P = 0.187). Two patients had partial flap necrosis (14.3%) but healed their defect. One patient had nonunion (7.1%). Limb salvage rate was 100%.

CONCLUSIONS

Bipedicled flaps can be used as an alternative to free flaps in distal third leg/foot defects in select patients. If distal extremity wounds cannot be covered with a bipedicled flap alone, the flap can be used an accessory flap to facilitate reconstruction with other local flaps.

Reverse Peroneal Artery Flap-A Workhorse Flap for Reconstruction of Large, Distal Defects of Ankle and Foot

Background  Reconstruction of large foot and ankle defects is a difficult task due to less available local soft tissue and more critical from functional point of view. To overcome the limitations associated with locoregional flaps and free flaps, reverse peroneal artery (RPA) flap was selected and its usefulness in reconstruction of distal large defects of the ankle and foot and its complications were studied. Materials and Methods  This is a prospective observational study done in 20 patients treated as cohort within 2 years and 8 months from January 2018 to August 2020. Large defects of foot and ankle were reconstructed with RPA flap and evaluated for its usefulness. Three cases were evaluated with computed tomography angiography postoperatively, to assess the vascular pattern. Conclusion  RPA flap is a versatile and very reliable flap for the reconstruction of large and distal defects of foot and ankle. It is safely done in children and in acute trauma without any major complications.

Clinical reliability of pedicled perforator flaps in the management of adult limb and trunk soft tissue sarcomas: Experience of two French expert centres

INTRODUCTION

Limb-sparing surgery combined with radiation has become the standard treatment for soft tissue sarcomas. Despite the many advantages of reconstruction procedures, such as muscle-sparing flap and local reconstruction, the use of pedicled perforator flaps remains non-consensual due to doubts about their reliability when associated with radiotherapy. This study evaluated their surgical reliability in reconstructive surgery for limb and trunk soft tissue sarcomas, in terms of healing time, wound disorders, and postoperative complications, regardless of radiation timing.

PATIENTS AND METHODS

We realized a retrospective, observational, bi-center study (Cancer University Institute of Toulouse Oncopole, France and Bergonié Institute Bordeaux, France) and describes pedicled perforator flaps performed between January 2015 and January 2021.

RESULTS

A total of 74 flaps were included. The median age of the population was 70-year-old. The group consisted of 68.8% (n = 51/74) propeller flaps. We found a partial necrosis rate of 28.4% (n = 21/74), scar disunion of 48.6% (n = 36/74), local infection of 10.8% (n = 8/74), and venous congestion of 13.5% (n = 10/74). Only 16.2% (n = 12/74) required secondary surgical repair to a local complication. The average length of stay was 7.3 days  [1.0-25.0]. The mean operating time of our flaps was 133.4 min [38.0-280.0].

CONCLUSIONS

Pedicled perforator flaps are a surgical technique that can be used in reconstructive surgery for limb and trunk soft tissue sarcomas in adults, regardless of radiation timing. However, these flaps carry a high rate of postoperative complications so they should be reserved for expert surgeons in referral centers.

The turbocharged wide anterolateral thigh perforator flap to reconstruct massive soft tissue defects in traumatized lower extremities: A case series

BACKGROUND

Extensive traumatic soft tissue defects in the lower extremities typically require complete coverage of exposed bone because inadequate coverage, such as partial flap loss, may result in bony infection and ultimately lead to limb salvage failure. To achieve complete coverage of these defects, we used the wide anterolateral thigh perforator flap in which the turbocharging procedure augments the blood flow. Herein, we describe our turbocharging technique and discuss its effectiveness.

METHODS

From January 2014 to December 2020, the turbocharged wide ALTP free flaps were used to treat 13 patients with massive traumatic soft tissue defects in the lower extremities, ranging in size from 22 × 10 cm2 (220 cm2) to 21 × 17 cm2 (357 cm2) (mean, 270 cm2). All ALTP flaps were supplied by perforators from both the transverse branch of the lateral circumflex artery (TB-LCFA) and descending branch of the lateral circumflex artery (DB-LCFA) simultaneously. The turbocharging procedure by connecting the TB-LCFA to a side branch of the DB-LCFA was carried out in all these flaps. A retrospective review of medical records for each patient was performed.

RESULTS

The size of the transferred ALTP flap ranged from 23 × 12 cm2 (276 cm2) to 23 × 19 (437 cm2) (mean, 331 cm2). The total number of perforators included in the flaps was three on average. All ALTP flaps survived completely without partial necrosis. The postoperative course was uneventful except for two cases with minor complications, including hematoma and partial necrosis of the recipient's skin.

CONCLUSION

Free transfer of the turbocharged wide ALTP flap can be a reliable and effective reconstructive method to obtain complete coverage of extensive traumatic soft tissue defects in the lower extremities and achieve successful limb salvage.

Identification of Unequal Flow-Carrying Capabilities of Choke Vessels in Rat Abdominal Flaps

BACKGROUND

Although the angiosome concept is a well-accepted theory, unexpected necrosis suggests that other factors can influence the flap survival. Our study uses the rat model to explore the flow capacity of the choke vessels across 2 angiosomes.

METHODS

The medioventral line of Sprague-Dawley rats' abdominal flap was equally divided into 4 sections, which were preserved in 7 different groups (n = 6/group): A, no dissection; B to D, preserve the inferior 1/4, 2/4, and 3/4 sections; E to G, preserve the superior 1/4, 2/4, and 3/4 sections. The ratio (%) of the survival area of the distal/proximal territory was calculated. Indocyanine green, lead-oxide gel imaging, hematoxylin and eosin, and CD31 histology tests were performed.

RESULTS

Compared with 96.0 ± 1.4% flap survival in group A, groups B, C, and D had distal territory flap loss (34.8% ± 4.1%, 65.0% ± 3.7%, and 94.3% ± 3.1% respectively). Group E lost the majority of the distal territory (3.5% ± 2.4%), whereas groups F and G (15.5% ± 3.8% and 79.2% ± 3.3%, respectively) had larger flap survival. Except for groups A and D, each of the other 2 groups showed statistically significant results ( P < 0.001). Indocyanine green indicated no blood flow at the superior 1/4 part. Lead-oxide gel and histology showed that the choke vessels residing along the medioventral line had no significant difference.

CONCLUSIONS

Choke vessels do not carry blood flow equally. Two categories of choke vessels-"resting" and "active"-are proposed. The "active" form has variable flow carrying capabilities when the flap is harvested in different designs.

Thermography Supported Color Duplex Ultrasound Accelerates ALT Perforator Imaging

BACKGROUND

 The anterolateral thigh flap is a versatile and dependable perforator flap and is a popular choice in the reconstruction of various body sites. The variable perforator anatomy suggests preoperative perforator imaging to improve safety and speed of dissection. An innovative perforator imaging technique is thermography, which lately gained attention in plastic surgery.

METHODS

 Thirty-two healthy participants were included in this randomized study. One thigh was examined with dynamic infrared thermography and consecutively with ultrasound, while the contralateral thigh was examined with ultrasound as standalone technology.

RESULTS

 The application of dynamic infrared thermography prior to ultrasound perforator identification significantly accelerated the ultrasound examination duration by 90 to 130 seconds. The mean duplex ultrasound examination duration correlated positively with the hotspot and perforator quantity per thigh.

CONCLUSION

 The addition of thermographic perforator mapping can accelerate color duplex ultrasound anterolateral thigh perforator imaging. Furthermore, thermography supplements color duplex ultrasound with crucial information on angiosome location.

Upper Facial Anastomoses Between the External and Internal Carotid Vascular Territories - A 3D Computed Tomographic Investigation

BACKGROUND

Facial regions with a high risk for causing injection-related visual comprise are dual-supply vascular areas such as the nose, glabella, and forehead. These regions have in common that they receive arterial blood supply both by branches of the internal (ICA) and the external carotid artery (ECA).

OBJECTIVE

The authors sought to investigate the anastomotic pathways between ICA and ECA branches in the upper face.

METHODS

Postmortem computed tomographic angiographic scans of n = 38 Chinese non-embalmed hemifaces (25 males, 13 females; mean age, 37.79 [11.8] years; mean BMI, 21.90 [2.3] kg/m2) were conducted. Data analysis relied on the calculation of depth, distances, and pathways of forehead and temporal arteries to investigate the number of anastomotic connections, the connecting branches, and the layer of connection between ICA and ECA territories.

RESULTS

Between ICA and ECA territories, only 1 connection in 57.9%, 2 connections in 31.6%, 3 connections in 5.3%, and 4 and 5 connections in 2.6% each were identified. A superficial connection was observed in 15.8% whereas in 84.2% the anastomotic connection was identified to be both superficial and deep.

CONCLUSIONS

Adverse events following facial minimally invasive soft-tissue filler injections for aesthetic purposes are not frequent but devastating if they occur. Anatomic knowledge as presented in this study can help to increase awareness of 3-dimensional vascular anastomotic pathways and identify safer injection zones and safer fascial planes. Evidence-based injection techniques should be followed, and safety aspects should be placed over the aesthetic outcome.

Impact of Diameter of Perforator in Pedicle and Different Managements of Intermediate Non-Pedicle Perforator on Flap Survival in Rats

BACKGROUNDS

The quantified relationship between perforator diameter and flap length can be supported, and the impact of different strategies of managements of a non-pedicled perforator with two major subfascial divisions on flap survival has never been explored.

MATERIALS AND METHODS

This study was divided into two parts. In Part I, 48 Sprague-Dawley rats underwent flap harvesting based on six perforators with a diameter gradient. Then, the flap length and perforator diameter were measured for establishment of an equation. In Part II, 32 rats underwent harvest of a transverse flap based on the right superficial epigastric perforator. In 16 rats the right intermediate iliolumbar perforator was severed in a distal-to-division approach, whereas, in the other 16 rats, it was severed with in a proximal-to-division approach. Necrosis rates and blood perfusion were also compared.

RESULTS

The equation y = 13.02 × x + 2.29 could be established between the perforator diameter in the pedicle (x) and the flap length (y) that could be supported with R²=0.8963 and P < 0.001.The transverse flap with a distal-to-division management of the intermediate iliolumbar perforasome was weaker in perfusion and had a necrosis rate of 49±4%, whereas the flap with a proximal-to division management had a significantly stronger perfusion and a lower necrosis rate of 21±2% (P<0.001).

CONCLUSIONS

The safe flap length that can be estimated based on a perforator with a known diameter can be calculated using y=13.02× x +2.29. A short segment of the stem of an intermediate perforator with two major subfascial branches should be preserved to augment flap survival.

Effects of Preconditioning With Transcutaneous Electrical Nerve Stimulation Monitored by Infrared Thermography on the Survival of Pedicled Perforator Flaps in a Rat Model

OBJECTIVE

Pedicled perforator partial or complete necrosis with a rate of 13.7%. This study was undertaken to test whether preconditioning with transcutaneous electrical nerve stimulation (TENS) monitored by infrared thermography protect against partial necrosis by converting the choke anastomoses to the true anastomoses via inducing heme oxygenase-1 (HO-1) in a rat pedicled perforator flap model.

METHODS

Seventy-two Sprague-Dawley rats were randomly assigned to the control, the TENS, the TENS + SnPP (tin protoporphyrin; HO-1 activity inhibitor; 50 μmol/kg) and the TENS +0.9% saline groups. On the unilateral dorsum of the rats, a rectangular flap donor site of 11 × 3 cm was marked out, which contained three perforator angiosomes and two choke zones. On days 1, 3 and 4, 1 hour of TENS (biphasic pulses, 25 mA, 80 Hz, 200 μs) was applied to the flap donor sites, respectively. On day 5, after the flap donor sites were assessed by infrared thermography, the flaps were harvested based on the deep circumflex iliac artery perforator.

RESULTS

Infrared thermography showed that the choke zones in the flap donor sites presented white in the TENS and the TENS +0.9% saline groups, whereas they presented red in the control and the TENS + SnPP groups. Postmortem arteriography showed that the number of arterioles across each choke zone significantly increased in the TENS and the TENS +0.9% saline groups compared with the control and the TENS + SnPP groups. Immunohistochemistry and western blot showed a significant increase in HO-1 in the choke zones after TENS preconditioning. The necrotic area percentage of the flaps was significantly decreased in the TENS (4.3% ± 2.6%) and the TENS +0.9% saline groups (4.5% ± 2.3%) compared with the control (24.8% ± 5.0%) (P < 0.001); there was no significant difference between the TENS and the TENS + SnPP (24.4% ± 7.3%) groups.

CONCLUSIONS

These data show that TENS preconditioning monitored by infrared thermography might be a promising strategy to prevent pedicled perforator flaps from partial necrosis.

Melatonin Improved the Survival of Multi-Territory Perforator Flaps by Promoting Angiogenesis and Inhibiting Apoptosis via the NRF2/FUNDC1 Axis

Background: Multi-territory perforator flaps are a reconstructive measure for repairing large soft tissue defects caused by tumors or trauma. However, the use of these flaps in clinical practice has been restricted due to the uncertain blood supply. Therefore, promoting the survival of the multi-territory perforator flap is critical for clinical repair and reconstruction. In our study, we explored the effects of melatonin (MLT) on multi-territory perforator flaps and the possible molecular mechanisms.

Materials and Methods: Seventy-two Sprague–Dawley rats (250–300 g) were randomly divided into 3 groups (n = 24): Control, MLT and MLT + ML385 groups. First, we assessed the survival area of the flap, followed by the micro-vessel density and CD31-positive vessel expression. Apoptosis of the skin flap under immunofluorescence and expression of the apoptosis-related proteins Bcl-2, Bax and Caspase3 were measured. Additionally, angiogenesis of the skin flaps was shown by angiography, and NRF2 and FUNDC1 mRNA and protein expression was detected by real-time PCR and western blotting.

Results: The results showed that MLT increased the survival area of the multi-territory perforator flap, which was related to increased angiogenesis and decreased apoptosis. We also found that mRNA and protein of NRF2 and FUNDC1 levels were significantly increased after MLT treatment, and an NRF2 inhibitor reversed the ability of MLT to enhance multi-territory perforator flap survival, promote angiogenesis and inhibit apoptosis and reduced FUNDC1 protein expression.

Conclusion: MLT promoted angiogenesis and inhibited apoptosis to promote the survival of multi-territory perforator flaps, which may be regulated via the NRF2/FUNDC1 axis.

The Medial Sural Artery Perforator Flap: A Historical Trek from Ignominious to “Workhorse”

Rather than just another “review,” this is intended to be an “overview” of the entire subject of the medial sural artery perforator (MSAP) flap as has been presented in the reconstructive literature from its inception in 2001 until the present, with any exceptions not purposefully overlooked. Unfortunately, the pertinent anatomy of the MSAP flap is always anomalous like most other perforator flaps, and perhaps even more variable. No schematic exists to facilitate the identification of a dominant musculocutaneous perforator about which to design the flap, so some adjunctive technology may be highly valuable for this task. However, if a relatively thin free flap is desirable for a small or moderate sized defect that requires a long pedicle with larger caliber vessels, the MSAP flap deserves consideration. Indeed, for many, this has replaced the radial forearm flap such as for partial tongue reconstruction. Most consider the donor site deformity, even if only a conspicuous scar on the calf, to be a contraindication. Yet certainly if used as a local flap for the knee, popliteal fossa, or proximal leg, or as a free flap for the ipsilateral lower extremity where a significant recipient site deformity already exists, can anyone really object that this is not a legitimate indication? As with any perforator flap, advantages and disadvantages exist, which must be carefully perused before a decision to use the MSAP flap is made. Perhaps not a “workhorse” flap for general use throughout the body, the MSAP flap in general may often be a valuable alternative.

Modified lateral gastrocnemius myocutaneous flap with extended anterior and/or inferior boundary

There is little information regarding the boundaries of the lateral gastrocnemius myocutaneous (LGM) flap. The aim of this study was to introduce the modified technique of the LGM flap with extended anterior and/or inferior boundaries and its anatomical basis. Five fresh lower limb specimens were perfused and radiographed. Between December 2003 and August 2018, 27 modified LGM flaps with extended anterior and/or inferior boundaries were raised in 27 patients to reconstruct the soft tissue defects over the middle and upper leg, knee, and lower thigh. Both the lateral popliteal cutaneous artery and musculocutaneous perforators from the lateral sural artery had rich linked arteries communicating with the chain-linked arterial network around both the posterolateral intermuscular septum and the sural nerve, and they also had rich transverse communicating arteries connecting with the perifascial arterial network overlying the anterior compartment in the upper and middle calf. Continuous fascial arterial networks were extended up to the level at the intermalleolar line. Twenty-three flaps survived uneventfully, 2 flaps displayed distal de-epithelialization, and 2 flaps (7.41%) developed partial necrosis. Osteomyelitis was cured successfully in all patients, and no relapse of infection was encountered during the follow-up period. Multiple feeder arteries are the arterial anatomic basis of the modified LGM flap. The modified LGM flap with extended anterior and/or inferior boundaries is feasible, and the modified flap with extended anterior boundaries is safe and reliable.

Infrared Thermographic Imaging of Chest Wall Perfusion in Patients Undergoing Coronary Artery Bypass Grafting

Coronary artery disease represents a leading cause of death worldwide, to which the coronary artery bypass graft (CABG) is the main method of treatment in advanced multiple vessel disease. The use of the internal mammary artery (IMA) as a graft insures an improved long-term survival, but impairment of chest wall perfusion often leads to surgical site infection and increased morbidity and mortality. Infrared thermography (IRT) has established itself in the past decades as a non-invasive diagnostic technique. The applications vary from veterinary to human medicine and from head to toe. In this study we used IRT in 42 patients receiving CABG to determine the changes in skin surface temperature preoperatively, two hours, 24 h and 6 days after surgery. The results showed a significant and independent drop of surface temperature 2 h after surgery on the whole surface of the chest wall, as well as a further reduction on the left side after harvesting the IMA. The temperature returned to normal after 24 h and remained so after 6 days. The study has shown that IRT is sufficiently sensitive to demonstrate the known, subtle reduction in chest wall perfusion associated with IMA harvesting.

Extended latissimus dorsi flap with propeller ascending design for reconstruction of a complex lateral lumbar defect: A case report and review of the literature

Lateral lumbar defects are rarely encountered and difficult to manage because of the limited reach of loco-regional flaps and the unfavorable position of recipient vessels for microsurgical transfer. The purpose of this report is to describe the innovative application of an extended latissimus dorsi (LD) flap with propeller ascending design in the field of lumbar reconstruction, reviewing current reconstructive options accepted for lateral lumbar defect. A 68-year-old male patient underwent wide full thickness resection for a solitary hepatocellular carcinoma metastatic lesion arising in the left lumbar region, resulting in an extensive soft-tissue defect (20 x 13 cm) with deep structures exposure. An extended LD flap with propeller ascending orientation was obliquely designed, with the distal third of the skin island laying over the trapezius muscle. The skin paddle measured 34 x 9 cm. The flap, including a cuff of proximal LD muscle spared by the oncological resection and a fasciocutaneous superior extension, underwent 90°clockwise rotation on the main thoracodorsal artery perforator and further caudal advancement allowed by section of the LD cranial tendinous insertion. The rotation-advancement movement allowed tension-free flap insetting, while donor site was closed by primary intention. The post-operative course was uneventful without any complications registered. At 12-months follow-up, a satisfactory result and a stable coverage were achieved. Due to the surgical complexity traditionally associated with the repair of defects located in the lumbar region, the case reported may help to provide a new alternative solution to extend the indications of local flaps in similar cases and simplify such reconstructions.

Tips on Raising Reliable Local Perforator Flaps

From early on in the development of plastic surgery, it was quickly realized that utilizing locally adjacent tissue, or “matching like with like,” yielded superior aesthetic reconstructions to those in which the tissue was derived from a distant location. In many cases, the use of a local perforator flap is a simpler procedure with less patient morbidity and a quicker recovery from surgery. The difficulty with local perforator flaps has been locating the supplying perforators, ensuring that the flap has a robust and reliable blood supply, and that sufficient tissue is able to be transferred. The recent reappraisal of our understanding of the blood supply of the integument has allowed, for the first time, the capacity to accurately and inexpensively, without the need for “high tech equipment,” locate perforators, as they emerge from the deep fascia into the overlying integument, and through a better understanding of the interconnecting anastomotic vessels between perforators reliably predict how much tissue can be safely raised on a single perforator, before surgery. Further, through the use of strategic “delay,” it is possible to manipulate the interconnecting vessels between the selected perforator and its surrounding neighbors to design a flap of tissue of any dimension, composed of whatever tissue we require, and safely transfer that tissue locally, or if required, distantly, as a free flap. This article will highlight these advances, explain their relevance in raising reliable local perforator flaps, and will, where possible, call attention to any pearls and pitfalls, and how to avoid complications.

Revisit of flap factors relating to partial necrosis of distally based sural flaps: an analysis of 435 cases in a single center

BACKGROUND

Partial necrosis is an ongoing topic in regard to flap complications of the distally based sural (DBS) flap However, the factors influencing partial necrosis of the flap remain in debate. The aim of the present study is to further illuminate the flap-related risk factors and the effects of several technical improvements.

METHODS

We retrospectively reviewed the data of 429 patients who underwent 435 DBS flaps between April 2001 and December 2019. The reconstruction outcomes, flap viability-related complications, and potential risk factors were compared between the survival group and partial necrosis group, as well as between group A (the procedures performed from April 2001 to March 2010) and group B (those from April 2010 to December 2019).

RESULTS

Among the 435 flaps, 39 flaps (8.97%) exhibited partial necrosis. With the increase of the top edge of the flap, the partial necrosis rate increased significantly (P < 0.05). When the length-to-width ratio [LWR] of the flap was more than 5:1 or the total length of the flap (the length of the skin island plus the length of the adipofascial pedicle) was more than 20 cm, the partial necrosis rate increased significantly (P < 0.05). The partial necrosis rate in group B (5.86%, 15/256) was significantly lower than that in group A (13.41%, 24/179) (P = 0.007).

CONCLUSIONS

The top edge of the flap is an essential indicator for predicting the prognosis of the DBS flap. When the total length of the flap is more than 20 cm or the LWR of the flap more than 5:1, the partial necrosis rate will increase significantly. Various technical modifications can lower the top edge of the flap and reduce the LWR of the flap and width of the skin island, and thus improve the flap survival effectively.

In Vivo Perforasome Perfusion in Hemi-DIEP Flaps Evaluated with Indocyanine-green Fluorescence Angiography and Infrared Thermography

There are no in vivo studies that evaluate the effect of perforator dissection on the perfusion territory of a perforator (perforasome). In this study, indocyanine green fluorescence angiography (ICG-FA) and infrared thermography (IRT) were used intraoperatively to evaluate perforasome perfusion in hemi-DIEP flaps.

Distally Based Sural Fasciocutaneous Flaps for Reconstructing Soft Tissue Defects Proximal and Distal to the Tarsometatarsal Joints: A Comparative Analysis

Distally based sural fasciocutaneous (DBSF) flaps are widely used for reconstructing soft tissue defects of the foot. The purpose of this paper was to compare the clinical efficacy of the use of flaps to repair defects in areas proximal and distal to the level of the tarsometatarsal joints in a relatively large number of patients and to analyze the effects of factors on the risk of developing partial necrosis of the flaps. Between April 2001 and December 2019, a total of 355 DBSF flaps were utilized to cover soft tissue defects in the foot. According to the furthest location of the defects reconstructed with the flaps, the flaps were divided into the proximal foot group (n = 260) and the distal foot group (n = 95). The partial necrosis rates, their influencing factors, and the clinical outcomes of the procedure were compared between the two groups. In the proximal foot group, the partial necrosis rate (6.2%, 16 of 260) was significantly lower than that in the distal foot group (14.7%, 14 of 95) (P < .05). The proportion of successful coverage of the defects using the flaps alone or in combination with a simple salvage treatment was comparable between the groups (P > .05). The ratio of unfavorable conditions in the distal foot group was higher than that in the proximal foot group (P < .05). DBSF flaps can be effectively utilized to repair defects in the proximal and distal areas of the foot. The use of a DBSF flap to repair defects in the proximal areas of the foot is superior to the use of DBSF flaps for repairing defects in the distal areas of the foot in terms of reliable survival of the flap.

[Flap design and preliminary clinical experience of the lower trapezius musculocutaneous flap carrying a portion of the latissimus dorsi muscle]

Objective

To explore the reliability and effectiveness of soft tissue defect reconstruction using the lower trapezius musculocutaneous flap carrying a portion of the latissimus dorsi muscle.

Methods

Between December 2014 and December 2019, 13 patients underwent the reconstruction of soft tissue defects in various sites using the lower trapezius musculocutaneous flap carrying a portion of the latissimus dorsi muscle. There were 10 males and 3 females, with an average age of 52.1 years (range, 29-83 years). Twelve wounds were resulted from resection of various malignant tumor, including 6 cases of head and neck tumors, 5 cases of shoulder and back tumors, 1 case of chest and back tumors. Among the 12 cases, 4 cases were complicated with wound infection and bone exposure, 1 case with skull defect and cerebral dura exposure, and 1 case with wound infection, skull necrosis, and cerebrospinal fluid leakage. One case was injured in a traffic accident, which resulted in infection wound in the back and shoulder and bone exposure. The sizes of the defect and musculocutaneous flap ranged from 11 cm×7 cm to 23 cm×15 cm and 25 cm×8 cm to 40 cm×14 cm, respectively. According to the spatial relationship between the donor and recipient sites, propeller flaps (8 cases) or percutaneous tunnel island flaps (5 cases) were used to transfer the myocutaneous flap to the recipient area to repair the wound. The donor site was directly closed and sutured in 9 cases, and those with excessive tension were repaired with free skin grafts in 2 cases or transferred flaps in 2 cases.

Results

After the operation, necrosis of the distal 4-cm of the musculocutaneous flap occurred in 2 cases. After debridement, the resultant wounds were reconstructed using a local flap and a posterior intercostal artery perforator flap, respectively. The remaining 11 myocutaneous flaps survived completely without arteries and veins crisis. The wounds in the donor and recipient areas healed by first intention. All the patients were followed up 1 to 48 months (mean, 7.4 months). The color and texture of the flap were good. During the follow-up, 1 patient underwent tumor resection again due to tumor recurrence, and 1 patient with a scalp hemangiosarcoma died due to unexplained thoracic hemorrhage. Tumor recurrence was not found in the remaining patients. The musculocutaneous flap coverage was stable and the infection was controlled.

Conclusion

The lower trapezius musculocutaneous flap carrying a portion of the latissimus dorsi muscle can be an alternation option to reconstruct refractory wounds with exposure of vital structures and organs and infection.

Risk factors related to the partial necrosis of the posterior tibial artery perforator-plus fasciocutaneous flap

PURPOSE AND BACKGROUND

The posterior tibial artery perforator-plus fasciocutaneous (PTAPF) flap is commonly used for defects over the distal lower extremity. However, the causes of partial necrosis of the PTAPF flap are unknown. This paper aimed to explore the factors related to the partial necrosis of the PTAPF flap.

METHODS

A retrospective study was conducted on 59 patients who received the PTAPF flap for soft-tissue defects between September 2007 and September 2017. The clinical outcomes of the flap were evaluated, and the patient and surgical factors related to flap survival were analyzed.

RESULTS

Of the 59 patients, 9 (15.25%) flaps exhibited partial necrosis. No significant differences were found between the survival and partial necrosis groups regarding gender, age, soft tissue defect site, length and width of the fascia pedicle, length of the skin island, length-width ratio (LWR), and pivot point (P > 0.05). However, the survival group showed significantly less width of the skin island and total length of the flap than the partial necrosis group (P < 0.05). Multiple logistic regression analysis revealed that the width of the skin island was an independent risk factor affecting partial flap necrosis (OR = 4.028; P = 0.041).

CONCLUSIONS

The PTAPF flap can be effectively used to repair small and medium wounds of the lower and middle leg, ankle and foot. As the width of the skin island exceeds 6 cm, the risk of partial flap necrosis significantly increases.

Distally Based Perforator-Plus Sural Neurocutaneous Flap with High or Low Pivot Point: Anatomical Considerations and a Retrospective Study of a Clinical Series of 378 Flaps

BACKGROUND

 This study is to describe the distribution of natural true anastomoses associated with the distally based perforator-plus sural neurocutaneous flap (sural flap), summarize our experience in the flap with high pivot point, and compare the outcomes between the flaps with high and low pivot points.

METHODS

 Five amputated lower limbs were perfused, and the integuments were radiographed. We retrospectively analyzed 378 flaps, which were divided into two groups: pivot points located ≤8.0 cm (low pivot point group) and >8.0 cm (high pivot point group) proximal to the tip of the lateral malleolus. Partial necrosis rates were compared between two groups.

RESULTS

 The arterial chain surrounding the sural nerve was linked by true anastomoses from the intermalleolar line to popliteal crease. True anastomoses existed among peroneal perforators and between these perforators and the arterial chain. There were 93 flaps with high pivot point and 285 flaps with low pivot point. Partial necrosis rates were 16 and 9.1% in the high and low pivot point group (p = 0.059), respectively.

CONCLUSION

 True anastomosis connections among peroneal perforators and the whole arterial chain around sural nerve enable the sural flap to survive with a greater length. The sural flap with high pivot point is a good option for reconstructing soft-tissue defects in the middle and distal leg, ankle, and foot, particularly when the lowest peroneal perforator presents damage, greater distance to the defects, discontinuity with the donor site, or anatomical variation.

Cervicofacial Defect Reconstruction Using the Pre-Expanded Medial Arm Flap Without Immobilization of the Upper Extremity

SUMMARY

The medial arm flap has multiple advantages when used for cervicofacial defect reconstruction but remains underused. The main drawback of the medial arm flap is that the patient must maintain the passive immobilized posture before the pedicle division. This clinical study aims to introduce a reconstructive method for cervicofacial defects using the medial arm flap without the immobilization of the upper extremity. This retrospective study was performed with data from 14 patients requiring pre-expanded medial arm flaps to reconstruct cervicofacial defects. Indocyanine green (ICG) angiography was used to detect perforators and evaluate the flap perfusion; all the flaps underwent pre-transfer tissue expansion. A total of 15 full-length medial arm flaps were used. All the perforators identified by ICG angiography were directly visualized during flap elevation. In four cases, poor perfusion areas in the flaps were noted by intraoperative ICG angiography. Combined with the clinical observation, parts with poor perfusion were resected. The average flap size was 203.9 ± 75.2 cm2 and ranged 20 to 28 cm in length after tissue expansion. The medial arm donor sites were closed directly or using another flap. All flaps survived completely. The patients were followed-up for 1 to 22 months. All patients and their family members were satisfied with the outcomes. Cervicofacial defect reconstruction using a medial arm flap with the aid of tissue expansion and ICG angiography can provide sufficient tissue for defect resurfacing and also eliminate the necessity of the immobilization of the upper extremity during surgery.

Distally based peroneal artery perforator-plus fasciocutaneous flap in the reconstruction of soft tissue defects over the distal forefoot: a retrospectively analyzed clinical trial

BACKGROUND

Distally based peroneal artery perforator-plus fasciocutaneous (DPAPF) flaps are widely used for reconstructing soft-tissue defects of the lower extremity. However, reports on the reconstruction of the defects over the distal forefoot using the DPAPF flaps are scarce. Herein, we describe our experience on the reconstruction of these defects using DPAPF flaps in a considerable sample size.

METHODS

Between February 2005 and August 2019, a total of 56 DPAPF flaps in 56 patients were used to reconstruct soft-tissue defects in the forefoot. In order to reduce the length of fascial pedicle and the total length of the DPAPF flaps, the ankles were fixed in dorsiflexion using a Kirschner wire before designing the flaps. The flaps were elevated by the anterograde-retrograde approach. Patient factors and flap factors were compared between the "survival" and "partial necrosis" groups.

RESULTS

Overall, 47 flaps had survived completely in one stage. Partial necrosis developed in nine flaps, with only one remnant defect covered using a local flap. By fixing the ankles in dorsiflexion, the length of the fascial pedicle was reduced approximately 2.35 ± 0.58 cm, the total length of the flap was simultaneously shortened by the same amount as the length of the fascial pedicle. The width of the fascia pedicle varied from 3.0 cm to 6.0 cm. The fascial pedicle width > 4 cm was found in 21 flaps. The partial necrosis rate of the DPAPF flaps with the top edge located in the 8th zone was significantly lower than that in the 9th zone (p < 0.05).

CONCLUSIONS

The DPAPF flaps can be effectively used to reconstruct the defects over the distal forefoot because of convenient harvest and reliability. By fixing the ankle in dorsiflexion with Kirschner wire and widening the fascial pedicle appropriately, the top edge and LWR of the flaps will be decreased, and thus the procedures are helpful for the flaps survival.

In Pursuit of the "Perforator" in the Perforator Skin Flap

Another congress of the World Society for Reconstructive Microsurgery (WSRM) this past year in Bologna was magnificent not just for the presentation of so many keynote lectures by the giants of our field nor the novel and innovative ideas shown by those who will someday follow in those footsteps, but by making all of us realize how many capable microsurgeons there are now practically everywhere in this world, doing incredibly important surgical management of challenges that previously were unmet and resulted in sheer devastation for so many of our patients. How much we are the same in our goals, aspirations, and abilities could not be overlooked, but it is amazing how much we also want to learn more together-each relying on the other. To do so, we must not forget our origins as we appropriately plan for the future. All this we philosophized in our WSRM panel on lower extremity reconstruction, while emphasizing on the surface the perforator flap that at the least today has caught everyone's attention. In this overview to follow, we once again tell two stories, starting with the beginnings of the concept of flaps in showing how the nomenclature has evolved over time according to our various surgical manipulations. Often overlooked, though, is a parallel timeline by the anatomists who have better elucidated the circulation to these flaps, where it will become obvious that often long ago the existence of perforators was recognized by them long before known by the surgeons. At least today, these two paths have at least temporarily intersected. Our pursuit of the "perforator" in the perforator skin flap has come full circle, following the course of the history of the flap itself-a pursuit of excellence.

Increasing Perfusion Pressure Does Not Distend Perforators or Anastomoses but Reveals Arteriovenous Shuntings

Background

It has been proposed that hyperperfusion of perforators and distension of anastomotic vessels may be a mechanism by which large perforator flaps are perfused. This study investigates whether increasing perfusion pressure of radiographic contrast in cadaveric studies altered the radiographic appearance of vessels, particularly by distending their anastomotic connections.

Methods

From 10 fresh cadavers, bilateral upper limbs above the elbow were removed. Three cadavers were excluded. Seven pairs of limbs were injected with lead oxide solutions via the brachial artery while distally monitoring intravascular pressure in the radial artery using a pressure transducer. One limb was injected slowly (0.5 mL/s) and the other rapidly (1.5 mL/s) to produce low and high perfusion pressures, respectively. Skin and subcutaneous tissue were then removed and radiographed.

Results

The filling of perforators and their larger caliber branches appeared unchanged between low- and high-pressure injections, with no significant increase in true anastomoses (P = 0.32) and no association between maximum perfusion pressure and number (P = 0.94) or caliber (P = 0.10). However, high-pressure injections revealed arteriovenous shunting with filling of the tributaries of the major veins.

Conclusions

This study demonstrated that increased perfusion pressure of the cutaneous arteries (1) did not change the caliber of vessels; (2) did not convert choke to true anastomoses; and (3) revealed arteriovenous shunting between major vessels with retrograde filling of venous tributaries as pressure increased. This suggests that it is not possible to distend anastomotic connections between vascular territories by increasing perfusion alone.

Lower limb perforator flaps: Current concept

Following a long period dominated by random fasciocutaneous flaps or muscle flaps, solutions to cover the lower limb have been largely diversified by the advent of so-called "perforator" flaps. Extended knowledge of vascular anatomy has propagated the development of this innovative procedure, in the objective of reducing morbidity. The existence of close to 400 perforator vessels in the body makes it possible to offer new flap perspectives for many defects, which were sometimes previously impossible to manage before except by free flap. For us, perforator flaps have become the current first-line solutions for small to medium size loss of substances. Understanding of vascular physiology and surgical experience are essential in choosing indications, detecting perforators, and modeling flaps to be optimally positioned in the reconstructive decisional algorithm. New skills are needed to master this type of reconstruction and limit failures, which implies a learning curve not only for flap design, perforator detection and surgical procedure, but also for monitoring and management of complications. In this manuscript, we outline the concepts and principles of the majority of the pedicled perforator flaps available for coverage of the lower limb, based on experience of more than 400 perforator flaps suitable for this localization.

Angiosome～From the Standpoint of Bypass Surgery

Although several studies showed that angiosome-guided endovascular treatment improved wound healing and major amputation rates in patients with chronic limb-threatening ischemia (CLTI), effectiveness of the angiosome concept to the treatment of ischemic foot remains to be elucidated, especially in bypass surgery. Arterial anatomy of the foot and ankle shows that there are multiple supplementary circulation including arterial–arterial connections and choke nexus, which indicates angiosome concept may carry limited importance in bypass surgery for CLTI. On the other hand, patients with diabetes or renal dysfunction have partial occlusion of arterial–arterial connections and, therefore, quite a few patients with CLTI in Japan may present with limited but impaired supplementary circulation around the ankle. This article reviews the arterial anatomy and circulation of the foot and ankle and discusses availability and limitations of angiosome-guided bypass surgery.