Posterior thigh flap in the reconstruction of the perineum and scrotum after Fournier’s gangrene

Summary

Objective: The posterior thigh flap is a fasciocutaneous flap predominantly based on perforating branches of the profunda femoris artery and the medial circumflex femoral artery, with additional vascular supply from perforators of the inferior gluteal artery. It can be used for reconstruction of perineal defects.

Method: We describe the case of a 40-year-old man with extensive Fournier’s gangrene resulting in complete loss of perineal skin coverage, the entire scrotum, and a large portion of penile skin. After radical necrectomies, intensive resuscitation for septic shock, and supportive therapy including hyperbaric oxygenation, the defect was reconstructed using bilateral posterior thigh flaps. All procedures were in accordance with the Helsinki Declaration.

Results: The postoperative course was uneventful. Both flaps remained fully viable, and donor sites healed per primam. No further necrectomy or surgical revision was needed.

Conclusion: The posterior thigh flap represents a reliable and safe method for reconstruction of extensive perineal defects with acceptably low donor-site morbidity.

Keywords:

Fournier’s gangrene – posterior thigh flap – gracilis flap – VRAM flap – perineal reconstruction – donor-site morbidity

Introduction

Reconstruction of the perineum ranks among the most demanding procedures in plastic and reconstructive surgery. The anatomical complexity of the region, the presence of heavy bacterial contamination, and the need to preserve not only function but also esthetics make these operations both technically and therapeutically challenging. Perineal defects most commonly arise after oncologic resections, trauma, or severe infections such as Fournier’s gangrene –⁠ a rapidly progressive and life-threatening necrotizing soft-tissue infection affecting the perineum, genitalia, and perianal region. It is characterized by necrosis of the skin, subcutaneous tissue, and fascia, rapid spread, and systemic sepsis.

The goals of reconstruction in the perineal region include wound closure, dead-space obliteration, protection of exposed structures, and restoration of function. Basic techniques –⁠ direct closure, healing by secondary intention, and local flaps –⁠ are suitable only for small defects without risk factors. Extensive defects require flaps with sufficient tissue volume. Common pedicled options include the caudally-based vertical rectus abdominis myocutaneous (VRAM) flap, the gracilis flap, and gluteal flaps. More extensive defects may require free flaps transferred using microsurgical techniques.

Each flap type has limitations. Although the VRAM flap provides substantial tissue volume, it weakens the abdominal wall and increases the risk of herniation. The gracilis flap has low donor-site morbidity but limited volume. In some cases –⁠ such as after previous abdominal surgeries or radiotherapy –⁠ these options are contraindicated.

The posterior thigh flap is a perforator-based fasciocutaneous flap from the posterior thigh, primarily supplied by perforators of the profunda femoris artery and the medial circumflex femoral artery, with supplemental supply from the inferior gluteal artery. The perforators are predominantly musculocutaneous, while distal parts may contain septocutaneous perforators. The flap typically ranges from 8 × 15 cm to 12 × 25 cm, with an arc of rotation of 120–180°. Indications include reconstruction of the perineum, ischial pressure ulcers, defects of the perineal body, gluteal region, vulva, and scrotum. It offers reliable vascularity, wide reach, the possibility of bilateral use, and low donor-site morbidity. Although described already in the 1980s, it is not commonly reported for perineal reconstruction.

The aim of this paper is to present a case of bilateral posterior thigh flap use in a patient with extensive soft-tissue loss of the perineum, scrotum, and penis after Fournier’s gangrene, and to discuss the advantages of the technique in the context of available literature.

 

Case report

A 40-year-old previously healthy man, smoker (approx. 10 cigarettes/day), without significant medical history, presented with perianal and perigenital pain and was initially treated as an outpatient with antibiotics for suspected periproctal phlegmon. Conservative treatment was ineffective, and both local and systemic conditions deteriorated. Extensive necrotic changes of the perianal and perigenital subcutaneous tissue developed, spreading to the scrotum and penis and involving the abdominal wall. Laboratory results showed a marked inflammatory response. The patient was febrile and developed septic shock.

He was urgently admitted and operated on for suspected periproctal abscess. Intraoperatively, extensive Fournier’s gangrene involving the perineum, scrotum, and perianal area was found. Radical debridement of all non-viable tissues was performed down to the deep subcutaneous layers, and the wound was dressed with antiseptic-soaked gauze (Fig. 1, 2). Due to septic shock, catecholamine support and intensive fluid resuscitation were required. He was transferred to the ICU and received triple intravenous antibiotic therapy (piperacillin/tazobactam, clindamycin, metronidazole). Early repeated debridements were required due to progression of necrosis into the right hypogastrium and mesogastrium, resulting in another extensive full-thickness skin defect. A protective sigmoidostomy was created in the left mesogastrium. After stabilization, the patient was transferred to another center (Department of Anesthesiology and Resuscitation, Military University Hospital Prague) for hyperbaric oxygen therapy (five sessions). Additional debridements and drainage of abscesses in the right buttock and thigh were undertaken, followed by stabilization.

 

Upon return to our department, bilateral peroneal nerve palsy was diagnosed, likely related to intensive anesthesiological management. EMG confirmed motor and sensory polyneuropathy with maximum involvement of the peroneal nerve. Pharmacotherapy and rehabilitation were initiated. Partial re-suturing of the hypogastric defect was performed, and negative-pressure wound therapy (VAC) applied to the residual abdominal wall defect.

The final pre-reconstruction defect included full-thickness skin loss of the entire scrotum, perineum, approximately 10 cm around the anus, the proximal half of the penis circumferentially, and the right hypogastrium.

Reconstruction of the perineal and scrotal defects was performed using bilateral posterior thigh flaps. Defects of the abdominal wall and penis were managed later using split-thickness skin grafts. The flaps were elevated as fasciocutaneous flaps from the posterior thighs in maximal dimensions (25 × 10 cm). The descending branch of the inferior gluteal artery was identified as the dominant pedicle, confirmed preoperatively using Doppler ultrasound (Fig. 3). After elevation, the flaps were transposed into the defect (Fig. 4, 5), and the donor sites were closed primarily after mobilization of the skin edges (Fig. 6). The flaps provided sufficient tissue to cover the perineum on both sides of the penis, including complete coverage of the testes and spermatic cords. A small part of the perianal defect could not be covered and was left to heal by secondary intention. The penile defect was later reconstructed with a split-thickness skin graft during the same session as abdominal wall reconstruction; the graft healed completely.

 

The postoperative course was uncomplicated. Both flaps remained fully viable, and donor-site incisions healed per primam. Fifteen days later, the residual hypogastric defect and penile shaft were covered with a split-thickness skin graft harvested from the right thigh (Fig. 7, 8). The graft on the abdominal wall was stabilized using negative-pressure therapy. Healing proceeded without complications (Fig. 9). After full integration of the flaps (5 weeks after reconstruction), complete healing of skin grafts, and closure of the perianal defect by secondary intention, the patient was fully  healed (Fig. 10).

 

Rehabilitation continued, and gradual improvement of the peroneal palsy was observed. At discharge, the patient was able to walk independently with crutches. He was discharged in good condition after 66 days of hospitalization, with follow-up managed on an outpatient basis. Six months later, the sigmoidostomy was reversed, restoring bowel continuity. Approximately eight months after healing, the patient developed a ventral hernia in the right hypogastrium at the site of the previous abdominal wall skin and subcutaneous defect. A sublay mesh hernioplasty and prophylactic appendectomy were performed. The patient is currently asymptomatic, with complete healing of the reconstructed perineal region and full functional recovery.

 

Discussion

Reconstruction of extensive perineal defects presents a major surgical challenge. The selection of an appropriate flap depends on defect size, tissue conditions, prior surgeries, and the need to minimize donor-site morbidity. The patient’s overall condition and ability to tolerate extensive reconstruction are also important considerations.

Published data describe the posterior thigh flap as a reliable option for perineal coverage. A retrospective study by Friedman et al. reported successful transfer in 26 of 27 flaps (survival rate 96.3%) with a low rate of major complications. Primary healing occurred in most cases, and early complications requiring secondary surgery occurred in 37% of patients [1]. Similarly high success (95.6%) is reported with the posteromedial thigh flap, which is anatomically comparable to the posterior thigh flap [2].

Other commonly used pedicled flaps –⁠ such as the gracilis or VRAM –⁠ also remain standard options but have limitations. A retrospective analysis of 40 patients with a gracilis flap reported reconstruction-site complications (hematoma, seroma, dehiscence) in 40% of cases and donor-site complications in 12.5% [3]. A meta-analysis of 19 studies found flap survival rates of 64% for gracilis flaps versus 84% for VRAM flaps [4]. Although the VRAM flap provides substantial tissue volume, its use is associated with higher donor-site morbidity, particularly abdominal wall weakness and secondary herniation (up to 9.9%) [5,6].

Although free microsurgical flaps are versatile and reliable, their use in extensive perineal reconstruction is often suboptimal. Following severe septic or necrotizing infections, the patient’s overall condition often precludes prolonged operative times required for microvascular anastomosis. Another limiting factor is the lack of suitable recipient vessels in the inflamed or previously operated perineal region, significantly increasing the risk of flap failure. Free-flap harvesting also adds donor-site morbidity and does not easily permit bilateral reconstruction, which was essential in our case. Given the technical complexity, increased risk of microvascular thrombosis in compromised tissue beds, and disproportionate physiological burden, free-flap reconstruction was deemed less suitable. The posterior thigh flap, by contrast, provided sufficient tissue, reliable vascularity, the possibility of bilateral use, and low morbidity, making it the method of choice.

The posterior thigh flap offers an excellent balance between tissue volume and low donor-site morbidity. It is especially useful in patients with prior abdominal surgeries or radiotherapy, which may contraindicate the VRAM flap. Esthetically, the results are acceptable, with scars hidden on the posterior thigh.

Our case supports findings from previous studies. Both flaps remained fully viable (Fig. 11), healing was uncomplicated, and donor sites healed per premium (Fig. 12). The posterior thigh flaps provided reliable coverage of exposed structures, especially the testes and spermatic cords, ensuring their vitality and function (Fig. 13).

 

Given the nature of the defects, the tissue and vascular conditions, and the patient’s metabolic and clinical status, the posterior thigh flap was an optimal choice compared to VRAM or gracilis flaps. Its anatomy matched the characteristics of the perineal and gluteal defects and allowed complete coverage.

The posterior thigh flap provides several advantages. It can be mobilized proximally up to the gluteal crease, has a large skin paddle (up to 25 × 10 cm), and a wide arc of rotation. While the VRAM flap also offers substantial reach, it would be excessively invasive for such a large and inferiorly located defect, and even then likely insufficient in size. The sigmoidostomy in the left mesogastrium –⁠ necessary for comfortable management of the open perineal wound and later flap healing –⁠ further complicated the use of a VRAM flap but did not impede harvesting of posterior thigh flaps. VRAM elevation is also technically more demanding and typically requires longer operative time.

The gracilis flap would have covered only part of such an extensive defect and would have required bilateral use. Compared with the gracilis flap, the posterior thigh flap is less invasive. Dissection and elevation were relatively rapid (total operative time 2 hrs 45 min), with reliable vascularity and reduced burden on the patient. The gracilis muscle also cannot be mobilized with sufficient reach for defects of this magnitude.

Another advantage of the posterior thigh flap is the ease of bilateral use, which was crucial in this case. Although VRAM flaps may be split, they are not suitable for such large defects. Gracilis flaps are available bilaterally as well, but were considered insufficient in volume for this specific case.

Vascular supply of the posterior thigh flap was confirmed preoperatively using Doppler ultrasound. The descending branch of the inferior gluteal artery appeared patent, although ultrasound mapping is not always fully reliable. Importantly, flap harvesting did not compromise abdominal wall stability, already weakened by existing defects and potential need for further abdominal surgery (e. g., stoma reversal, hernia repair).

 

Conclusion

Reconstruction of extensive defects after aggressive soft-tissue infections of the genital and perineal region is not common in routine surgical practice.

The posterior thigh flap represents a reliable and effective method for reconstruction of perineal defects. It is particularly suitable when extensive coverage of the perineum and scrotum is required while minimizing donor-site morbidity. It preserves the integrity of the abdominal wall and provides sufficient tissue for coverage of exposed structures. It is also appropriate when flaps from the abdominal wall or medial thigh cannot be used.

Advantages of this method include stable vascularity, adjustable size with a large arc of rotation, the possibility of bilateral use, and low donor-site morbidity. The esthetic outcome is acceptable, with scars on the posterior thigh easily concealed.

 

Acknowledges

Photographic documentation was obtained and archived in accordance with internal regulations and used with the patient’s consent for scientific publication.

Internal sources: data obtained from the hospital information system of the University Hospital Hradec Králové and from archived photographic documentation with the patient’s informed consent.

Conflict of interest

The authors declare that they have no conflict of interest related to the creation of this article, and that this article has not been published in any other journal with access to congress abstracts.