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.

Conjoined thoracodorsal perforator-supercharged dorsal intercostal artery perforator propeller flap for reconstruction of a complex upper back defect: Case report and review of the literature on supercharged pedicled perforator flaps

The reported complications' rate of perforator propeller flaps is variably high, but the etiology of distal flap necrosis, potentially linked to vascular insufficiency, is yet to be clarified. Vascular augmentation procedures have been previously described involving an extra anastomosis of a superficial vein, while a perforator-to-perforator supercharging approach has been only sporadically documented in literature. We present a case of perforator-to-perforator vascular supercharging of an extended dorsal intercostal artery perforator (DICAP) propeller flap to provide a salvage option for pedicled flap complicated by venous congestion. A 71-year-old male patient underwent Dermatofibrosarcoma Protuberans resection in the upper back, leading to a 17 × 17 cm defect with bone exposure. A 30 × 9 cm DICAP propeller flap was planned, with the distal third of the flap designed over the adjacent Thoracodorsal artery perforasome, in a conjoined fashion. Considering the small DICAP pedicle caliber and the flap lateral extension, a thoracodorsal artery perforator vein was dissected and included in the distal flap. Once the flap was raised on its main pedicle, the skin paddle turned blue, showing signs of venous insufficiency. Indocyanine green angiography (ICG) showed a viable proximal half of the flap. Hence, after rotating the skin paddle to reach the upper margin of the defect, an additional anastomosis between the perforating thoracodorsal vein and the perforating vein of the dorsal scapular pedicle was performed according to the perforator-to-perforator approach. Doing so, both clinical and ICG examinations showed a well perfused flap, with normal capillary refill. The postoperative course was uneventful, and the patient obtained a good oncological and reconstructive result 4 months postoperatively. The second Vasconez law ("all of the flap will survive except the part that you need") is often encountered in propeller flaps surgery. Our case shows that it is possible to prevent or overcome this problem by planning appropriate vascular augmentation procedures according to the perforator-to-perforator approach, being guided by advanced vascular imaging tools like ICG.

The clinical application of arterialized venous flaps in repairing large area of soft tissue defects of extremities

BACKGROUND

The reconstruction of microsurgery emphasizes the low morbidity of donor sites. The arterialized venous flaps (AVFs) are tissue flaps harvested without conventional vascular pedicles. However, reports of high necrosis rates and poor understanding of physiology hindered the application of many surgeons in clinical practice. Recently, experimental and clinical studies have demonstrated the feasibility and relative reliability of various AVF techniques. This study aims to report the clinical results of the arterialized venous free flaps in reconstructing soft tissue defects of limbs and propose methods to improve flap perfusion, extending the indications for using the flaps based on the authors' clinical experiences.

METHODS

We retrospectively reviewed the records of 16 patients that underwent arterialized venous free flaps for limb wound reconstruction from January 2019 to June 2021. Following the venous network on the calf's tibial side, large venous flaps can be designed.

RESULTS

Of the 16 cases, 14 (87.50%) cases (including 8 cases significantly congested with tension blisters) showed complete survival, and 2 (12.5%) cases, which had only one vein performed anastomosis of the efferent vein according to the vascularity of the recipient bed, showed partial necrosis. In all cases, no infection or other specific complications occurred in the donor areas.

CONCLUSION

The rate of congestion and necrosis of arterialized venous flaps is still challenging, but it will be suitable for large soft tissue defects of limbs in the future.

Effects of Distal Arterial Supercharging and Distal Venous Superdrainage on the Survival of Multiterritory Perforator Flaps in Rats

BACKGROUND

Which one of the two measures, distal arterial supercharging (DAS) and distal venous superdrainage (DVS), is better to enhance flap survival? No consistent conclusions have been reached.

METHODS

All flaps were pedicled on the deep circumflex iliac vessels. Seventy-two healthy male rats were distributed to four groups randomly: DAVS group (distal arteriovenous supercharging group), the thoracodorsal (TD) artery and TD vein were preserved; DAS group (distal arterial supercharging group), the TD vein was ligated; DVS group (distal venous superdrainage group), the TD artery was ligated; control group, the TD artery and TD vein were ligated. Flap survival rate was evaluated on postoperative day 7. Flap angiography was performed to assess vascular changes of the flap. Microvascular density (MVD) was evaluated by hematoxylin and eosin staining, and CD34-positive microvessel density was measured by immunohistochemistry. Vascular endothelial growth factor (VEGF) level was measured by western blot. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were evaluated using specialized commercial kits.

RESULTS

The mean flap survival rate was increased significantly in DAVS and DAS groups than in DVS and control groups. DAVS and DAS groups had higher flap vascularization, MVD, CD34-positive microvessel density, VEGF expression and SOD level compared to DVS and control groups. DAVS and DAS groups also had lower MDA level relative to DVS and control groups.

CONCLUSION

DAS is more conducive to improving the survival rate of the multiterritory perforator flap compared to DVS, mainly by enhancing angiogenesis and preventing ischemia-reperfusion (I/R) injury.

Safety and Vascular Impact of Perforator Propeller Flaps during Distal Lower Limb Reconstruction

Background:

In distal lower limb defects, the paucity of local tissues dictates a free-flap (FF)-based reconstruction frequently. The propeller perforator flap (PPF) offers a good alternative when the patient or the limb or both are not fit for FF-based reconstruction. Also, in contexts of restricted healthcare resources, armed conflict scenarios, or during pandemics like the ongoing COVID-19 pandemic, PPF is considered a valuable alternative to free-flap-based reconstruction. Additionally, PPFs are less sacrificing in terms of major limb vessels and distal limb vascularity. Yet, the distal lower limb vascular impact for PPF-based reconstruction has not been studied before.

Methods:

In total, 23 patients with distal lower limb defects were reconstructed with PPFs. By using U/S arterial duplex, the peak arterial velocity (PA velocity) was measured pre and postoperatively in 15 (65.2%) out of the 23 patients. This measurement was done to the vessel segment distal to the used perforator.

Results:

An estimated 21 out of 23 flaps succeeded to reconstruct the patients’ defects safely and to give all patients stable coverage without further surgeries. Only two patients had flap failure, which was managed successfully through additional reconstruction sessions. The difference between pre- and postoperative PA velocity was not statistically significant.

Conclusions:

PPFs are a safe cost-effective reconstruction modality for distal lower limb defects. This advantage is very valuable in cases of restricted healthcare resources, wars, and during pandemics. In terms of distal limb vascularity, PPFs have no significant impact and can be used safely.

The Role of Supermicrosurgery and Arborization Capture in Improving Free-styled Propeller Flap Survival

Background:

Propeller flaps have a higher-than-normal incidence of partial flap necrosis. Although venous supercharging has been shown to reduce this risk, its application is limited outside the scope of lower limb propeller flaps. In this article, we look at the ability of arborization capture and supermicrosurgery to allow propeller flaps to capture adjacent perforasomes and significantly improve flap survival.

Methods:

In a retrospective case series across two institutions, the outcomes of two groups of patients who had propeller flaps were compared. Group A patients were those who had conventional free-styled propeller flaps (n = 25), whereas Group B (n = 19) patients had propeller flaps algorithmically selected for either (1) arborization capture or (2) venous supercharging, or both. Two-way ANOVA analysis was performed to evaluate inter-group differences.

Results:

Conventional propeller flaps had a 64% complete survival rate (32% partial necrosis rate and a 4% total necrosis rate) compared with a 94% complete survival rate in modified propeller flaps. Of the 12 cases of arborization capture (perforator complex diameters of 1–2 mm), only one flap sustained partial flap loss, whereas all seven supercharged propeller flaps (selected for perforator diameter <1 mm, with venous supercharging, in addition to arborization capture) survived completely.

Conclusions:

The arborization technique should be the mainstay technique for all propeller flaps with perforator complex diameters of less than 2 mm while supercharging further enhances its survival, particularly in perforator complex diameters of less than 1 mm.

[Application of free-style perforator pedicled propeller flap to repair the wound after extensive resection of skin malignant tumor on the thigh]

OBJECTIVE

To explore the effectiveness of free-style perforator pedicled propeller flap to repair the wound after extensive resection of skin malignant tumor on the thigh.

METHODS

Between December 2016 and June 2019, 12 patients with skin malignant tumor on the thigh were treated. There were 9 males and 3 females, aged from 8 to 65 years (median, 38.5 years). The etiologies included basal cell carcinoma in 3 cases, squamous cell carcinoma in 7 cases, fibrosarcoma in 1 case, and malignant melanoma in 1 case. The disease duration ranged from 5 months to 10 years (median, 7.5 years). Color Doppler ultrasound was used to detect and mark at least one perforator vessel before operation. After extensive resection, the size of wound ranged from 5.0 cm×3.5 cm to 8.5 cm×6.5 cm. In the range of 1-3 cm from the edge of the lesion, the perforator vessels were explored again from the deep surface of the deep fascia to confirm and mark. The perforator vessel with diameter greater than 0.5 mm and closest to the edge of the lesion was taken as the rotation point of the flap. According to the wound size and shape, the free-style perforator pedicled propeller flap in size of 8.0 cm×3.5 cm to 12.5 cm×6.0 cm was designed. The wound was repaired with the big blade of the flap. The donor site was closed directly with the aid of the small blade.

RESULTS

The distal part of the skin flap was necrosis after operation, and healed after symptomatic treatment such as dressing change; the other flaps survived successfully and the wounds healed by first intention. All incisions at the donor site healed by first intention. All patients were followed up 5-24 months (mean, 10.2 months). During the follow-up, there was no recurrence of tumor. The flap had good elasticity and texture with no obvious swelling or scar hyperplasia, and the appearance was satisfactory; the hip and knee joint activities were normal.

CONCLUSION

Based on the extensive skin blood supply and abundant perforator vessels of the thigh, the free-style perforator pedicled propeller flap is an ideal flap for repairing small or medium wound after extensive resection of skin malignant tumor on the thigh.

Perforator-based propeller flap for coverage of lower leg: Single centre experience

This study was conducted to assess outcomes of propeller flaps for reconstruction of small- to medium-sized defects in the distal third of the leg. Of 53 lower third leg defects covered using the propeller flap, 43 survived without complications. Only minor complications were seen and no flap was lost completely. The propeller flap is thus a safe option for medium-sized defects of the lower leg.

Comparison of arterial supercharging and venous superdrainage on improvement of survival of the extended perforator flap in rats

BACKGROUND

Arterial supercharging and venous superdrainage have been the commonly used vascular augmentation techniques for resolving partial loss of flaps in reconstructive surgery. It remains controversial which one of them is more effective in improving flap survival. The purpose of this study was to compare the effect of distal venous superdrainage and arterial supercharging on the survival of an extended dorsal perforator flap in rats.

MATERIALS AND METHODS

Sixty Sprague-Dawley rats were randomly divided into three groups (n = 20 in each group). An extended dorsal perforator flap with the size of 3 × 12 cm based on the deep circumflex iliac artery and vein was elevated in each rat. In arterial supercharging group, the thoracodorsal artery was retained as the distal supercharging vessel; In venous superdrainage group, the thoracodorsal vein was retained as the distal superdrainage vessel. In control group, no other arteries and veins were retained except the main vascular pedicle. On the seventh day after operation, the survival area of flap was calculated as a percentage of viable area to the total flap. Vascular changes in the choke zones were assessed by angiography. Microvascular density and diameter were assessed via immunohistochemistry staining of CD31 on the fifth day after operation.

RESULTS

The flap survival area in arterial supercharging group was significantly higher than that in venous superdrainage group (98.9 ± 0.8% vs. 81.5 ± 3.5%, p < .001). By gross observation, the extent of dilation of choke zone vessels in venous superdrainage group was smaller compared with that in arterial supercharging group. The density of CD31-positive vessels and the diameter of choke zone vessels in arterial supercharging group were significantly larger than that in venous superdrainage group (23.4 ± 4.6 mm^-2 vs. 13.1 ± 4.2 mm^-2 , p < .05; and 37.5 ± 5.8 μm vs. 27.8 ± 4.9 μm, p < .05).

CONCLUSION

Compared with venous superdrainage, distal arterial supercharging in the potential territory resulted in better survival of an extended dorsal perforator flap in a rat model.

Propeller Flaps for Reconstruction around the Foot and Ankle

The propeller flap challenges conventional wisdom for the safe raising of flaps. Its unique design is based on a belief that a sizeable fasciocutaneous flap can be perfused by only a single perforator. What is more remarkable is the concept that this cleanly dissected pedicle can continue to safely perfuse the flap even when it is twisted 180 degrees. Clearly, meticulous technique is essential and the key points in raising this flap and its versatility for reconstruction of defects around the foot and ankle are discussed in this article.

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.

Our Definition of Propeller Flaps and Their Classification

The term propeller flap was introduced for the first time by Hyakusoku to define an island flap, based on a subcutaneous pedicle hub, that was rotated 90 degrees to correct scar contractures due to burns. With the popularization of perforator flaps, the propeller movement was applied for the first time to a skin island vascularized only by an isolated perforator, and the terms propeller and perforator flap were used together. Thereafter, the surgical technique of propeller flaps evolved and new applications developed. With the "Tokyo consensus," we proposed a definition and a classification schema for propeller flaps. A propeller flap was defined as an "island flap that reaches the recipient site through an axial rotation." The classification included the SPP (SPP) flap, the perforator pedicled propeller (PPP) flap, and the supercharged PPP (SCP) flap. A recent update added a new category, the axial pedicled propeller (APP) flap. Here we propose our updated and comprehensive classification of propeller flaps, taking into account the previous classification and subsequent publications. Based on their vascular pedicle, we consider the following five types of propellers: (1) SPP flap, 2.PPP flap, its subtype (2a) SCP flap, (3) APP flap, (4) muscle propeller flap, and (5) chimeric propeller flap. The variables that can be taken into account in the classification are as follows: type of nourishing pedicle, degrees of skin island rotation, position of the nourishing pedicle, artery of origin of the pedicle, and flap shape.

Outcomes of Vacuum Sealing Drainage Treatment Combined with Skin Flap Transplantation and Antibiotic Bone Cement on Chronic Tibia Osteomyelitis: A Case Series Study

BACKGROUND Chronic osteomyelitis is one of the currently refractory diseases. The aim of this study is to discuss the method and curative effects of vacuum sealing drainage (VSD) treatment combined with skin flap transplantation and antibiotic bone cement for chronic tibia osteomyelitis. MATERIAL AND METHODS For this study, 18 cases of open fracture secondary chronic tibia osteomyelitis were selected. After the granulation tissue of the wound surface became fresh and infection was controlled, the wound surface was repaired with a medial head of gastrocnemius transfer flap or a myofascial and cutaneous island pedicle flap with a collateral vessel nourished by the retrograde sural nerve. VSD combined with focus debridement and antibiotic bone cement filling was conducted. After inflammation was completely regulated, elective bone cement extraction, bone grafting, and internal fixation were performed. Within 2 to 3 years of follow-up post-surgery, the satisfaction and recurrence rates were evaluated. The patients' pre-operative and post-operative recovery of limb functions were compared according to the Enneking scoring system. RESULTS The patients did not suffer from osteomyelitis recurrence, with the exception of 1 case that manifested osteomyelitis recurrence and recovered through surgical treatment within the period of follow-up. The satisfaction and recurrence rates of these study cases post-surgery were 94.4% and 5.6%, respectively. The average functional recovery post-surgery was 81.5% of normal function. CONCLUSIONS Vacuum sealing drainage combined with skin flap transplantation and antibiotic bone cement is an effective treatment for chronic tibia osteomyelitis.

Distally Based Medial Plantar Flap: A Classification of the Surgical Techniques

The proximally based medial plantar flap is considered to be the reference standard for heel reconstruction. Although less well-studied, a distally based medial plantar flap is a suitable alternative when used to cover a distal foot defect, especially of the hallux, first metatarsal, or metatarsophalangeal joint. Our objective was to provide a complete description and propose a classification of the different surgical procedures used to harvest this flap. A review of the data reported in the MEDLINE database until May 2017 concerning the distally based medial plantar flap was performed. We have illustrated the different surgical procedures through a case series. Three approaches or "types" of flap have been described, and we have proposed a classification for reconstructive surgeons. In type 1, the plantar pedicle is ligatured before division into the medial and lateral plantar artery. In type 2, the medial plantar pedicle is cut proximally just after division. In type 3, the flap is harvested to include the fasciocutaneous perforator vessels, as an advancement flap or a propeller perforator flap. A distally based medial plantar flap affords adequate and reliable coverage of the weightbearing zone. Because the donor site drawbacks are minimal, this flap is a useful option for distal foot reconstruction, and reconstructive surgeons should remember this flap. The type 1 flap appears to be associated with a minimal risk of flap necrosis, even in those with diabetes or arteriopathy, and can cover even the most distal defect.

Free antero-lateral thigh flap for total knee prosthesis coverage after infection complicating malignant tumour resection

BACKGROUND

Infection is a common complication of major lower limb-sparing surgery with massive total knee prosthesis (MTKP) reconstruction after extensive tumour resection. When free tissue transfer is required to cover the prosthesis, musculo-cutaneous flaps are usually preferred based on proven efficacy when used in both one-stage and two-stage procedures. The use of a free fascio-cutaneous antero-lateral thigh (FC-ALT) flap in 3 patients with infected knee reconstructions is reported here.

MATERIAL AND METHOD

A retrospective study was performed of 3 patients in whom a free FC-ALT flap was used during a two-stage procedure to treat MTKP infection after femoral sarcoma resection.

RESULTS

Free FC-ALT flap transfer and exchange arthroplasty were successful in all 3 patients. Two years after the procedure, no patient had required amputation or experienced recurrent infection.

CONCLUSION

A free FC-ALT flap can provide adequate coverage of infected MTKP and deserves to be viewed as a valid alternative to free muscle flaps.