Pelvic Ring Reconstruction with an Osteocutaneous Fibula Flap for Abdominal Wall Repair in Adults with Bladder Exstrophy

Abstract

Abdominal wall repair in adults with bladder exstrophy is challenging. We present a case of a 46-year-old woman with bladder exstrophy presenting with a large midline incisional hernia associated with a 13-cm hypoplasia of both pubic rami that precluded fixation of any abdominal mesh. A two-stage approach was adopted. First, a free vascularized osteocutaneous fibula flap was used to reconstruct the pelvic ring. After complete bone union 18 months later, a mesh was anchored to the fibula flap to restore the abdominal wall competence. After 2 years of follow-up, no hernia recurrence was observed, and the patient reported improved quality of life and self-esteem. This novel technique may provide long-term stability and good functional outcomes for reconstruction of the abdominal wall in selected adults with bladder exstrophy.

Keywords

microsurgery - fibula flap - pelvic ring reconstruction

Introduction

Classic bladder exstrophy is a congenital disorder with an estimated occurrence ranging from 1/10,000 to 1/50,000 births. Males are affected five to six times more frequently than females.[1] It belongs to a spectrum of diseases resulting from the absence of the proper caudal migration of the embryonic body stalk insertion and the persistence of the cloacal membrane, with mesoderm ingrowth, resulting in a lack of development of the lower abdominal muscles and pelvic bones.[2]

Cephalocaudal anomalies associated with classic bladder exstrophy typically extend between the umbilicus and the anus. Abnormal pelvic bone structures—such as pubic symphysis diastasis—frequently occur due to the outward rotation of the innominate bones and pubic rami.[3] These patients often present with ventral hernia, attributable to the laxity of the abdominal wall due to weakened rectus abdominis muscles. Moreover, the lower abdomen and perineum may experience progressive impairment following multiple surgical procedures over the patient's lifetime.

Case Report

A 46-year-old woman was referred to our institution presenting with a M2-3-4-5 W3 incisional hernia according to the European Hernia Society classification,[4] in the context of congenital bladder exstrophy ([Fig. 1]). She had undergone multiple procedures over the years. The computed tomography (CT) scan revealed a significant hypoplasia of both pubic rami, showing a 13-cm pubic diastasis, which precluded the attachment of any prosthetic mesh ([Fig. 2]).

Fig. 1 Clinical findings before the two-stage abdominal wall reconstruction.

Fig. 2 Radiological findings before the two-stage abdominal wall reconstruction.

The clinical approach was managed by an interdisciplinary team, involving the abdominal wall surgery department and the plastic and reconstructive surgery department. A decision was made to restore the integrity of the abdominal wall through a two-stage procedure: first, the pelvic ring would be reconstructed with a free vascularized osteocutaneous fibula flap to provide a stable support for the subsequent attachment of an abdominal mesh.

During the first stage, the fibula flap was harvested as commonly described. A skin paddle for flap monitoring was designed in the distal third of the leg after perforator assessment with a handheld ultrasound. A narrow skin paddle was included to allow primary closure of the donor site. A left inguinal incision was performed to expose the recipient vessels. The length of the bone was established according to the CT study results, we thus harvested a 15-cm long flap to fit the defect after debridement of the pubic remnants. A laparotomy incision was performed to transfer the flap into the pelvic region. The fibula was fixed with 2-mm cortical screws and periosteal suture. The left common femoral artery, the left greater saphenous vein, and the left superficial epigastric vein were used as recipient vessels in end-to-side and end-to-end fashion, respectively. After blood flow through the anastomoses was confirmed, and the abdominal wall was closed. Handheld Doppler was used for flap monitoring. Splinting was not necessary; however, hip flexion or any compression on the left groin was prohibited during the first 7 days to avoid any vascular complication. Postoperative period was uneventful and 18 months later the CT scan confirmed bone union. During the second stage, a laparotomy incision was made avoiding any damage to the skin paddle of the flap. The incisional hernia repair was performed using the Rives-Stoppa technique.[5] A dual 20 × 45 cm prosthesis was fixed with nebulized cyanoacrylate in the retromuscular portion. It was extended downward covering the perineum and backward embracing the rectum and fixed to the sacral promontory by two anchor points of the Super REVO-FT device and two pairs of high-strength polyester suture strands. Finally, it was anchored with polypropylene loose stitches to both Cooper's ligaments and the fibula flap ([Fig. 3]). No hernia or abdominal laxity was noticed after 2 years of follow-up ([Figs. 4] and [5]). No urinary incontinence nor fecal incontinence were observed. A satisfactory aesthetic result was achieved, and the patient experienced a remarkable improvement in her quality of life and self-esteem. [Videos 1] and [2] show the clinical difference when asking the patient to perform a Valsalva maneuver before and after the reconstruction, respectively.

Fig. 3 The abdominal mesh was anchored to the fibula flap (blue vessel loop) during the second stage.

Fig. 4 Clinical findings after the two-stage abdominal wall reconstruction. A skin paddle (*) was included to monitor the flap.

Fig. 5 Reconstruction of the pelvic ring with an osteocutaneous fibula flap (white arrow).

Video 1 Physical examination before the abdominal wall repair.

Video 2 Physical examination after the abdominal wall repair.

Discussion

While management of bladder exstrophy during childhood is usually straightforward, abdominal wall reconstruction in adults is often debated. Some authors have described primary closure with satisfactory results. The use of a human acellular dermal matrix has also been reported.[6] Several abdominal flaps have been described as well.[7] Ete et al[8] reported a three-layer reconstruction with good functional results. However, cases with significant pubic diastasis may be particularly challenging since this might preclude the fixation of an abdominal mesh. Manahan et al[9] described the use of an acellular dermis fixed with polypropylene sutures in an interrupted horizontal mattress fashion on the internal aspect of the pelvis with the aim to create a supportive point. This technique might be a reliable option for minor defects. Nevertheless, when large bone defects necessitate reconstruction, “like-with-like” reconstruction with autologous vascularized bone may offer superior long-term results, despite its technical complexity. The fibula flap for pelvic ring reconstruction has already been described in the literature after major oncologic resections, with high rate of bone union and long-term functional outcomes. This technique has shown to allow weight bearing in those patients, and most of them were able to return to unaided ambulation.[10] Having demonstrated the capacity of the fibula to withstand major tensile and axial forces, it seems reasonable to consider it a strong point of fixation for the abdominal mesh.

Conclusions

Pubic diastasis in adults with bladder exstrophy may preclude mesh fixation for abdominal wall repair. We present a two-stage abdominal wall repair associating an osteocutaneous fibula flap to reconstruct the pelvic bones defect. After complete bone union, a mesh was anchored to the fibula with no recurrence of hernia after 2 years of follow-up. To the authors' knowledge, this is the first case of abdominal wall repair in an adult with bladder exstrophy after reconstructing the pubic bones diastasis with an osteocutaneous fibula flap. This novel technique may yield long-term stability to the pelvic ring, serving as a solid fixation point to secure an abdominal mesh and restore the abdominal wall integrity in selected patients.

Conflict of Interest

None declared.

• References

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Publication History

Article published online:
04 July 2024