Reconstruction of Symphysis Pubis Osteomyelitis Secondary to Chronic Ischial Pressure Sore Using a Biceps Femoris Turnover Flap: A Case Report

Article information

J Wound Manag Res. 2026;22(2):99-105

Publication date (electronic) : 2026 June 30

doi : https://doi.org/10.22467/jwmr.2026.03622

Jae Hyun Kim, Jun Il Kim, Chan Min Chung

Department of Plastic and Reconstructive Surgery, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea

Corresponding author: Chan Min Chung, MD, PhD, Department of Plastic and Reconstructive Surgery, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, 22 Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang 14068, Korea, E-mail: cmchung@hallym.or.kr

Received 2026 March 27; Revised 2026 May 16; Accepted 2026 May 22.

Abstract

Introduction

Pressure ulcers, also known as decubitus ulcers or pressure sores, are a common complication in patients with impaired mobility, affecting 29.1%–46% of patients with paraplegia [1]. These ulcers develop due to sustained pressure, shear forces, and friction over bony prominences in patients who require prolonged bed rest or wheelchair dependence [2]. Among the common anatomical sites, the ischial region is vulnerable because of constant pressure and repetitive friction during prolonged sitting. Ischial pressure sores often present as deep, undermined wounds [3]. Although computed tomography (CT) may be useful for evaluating cortical bone destruction, magnetic resonance imaging (MRI) is considered the most sensitive modality for detecting early marrow involvement, soft-tissue extension, and abscess formation [4]. If neglected or inadequately treated, ischial pressure sores can progress to deep soft tissue infections and contiguous osteomyelitis (OM). In rare cases, the infection may extend anteriorly to involve the pubic symphysis, resulting in symphysis pubis OM [5]. The standard treatment of OM includes adequate surgical debridement or resection of necrotic bone and infected soft tissue, effective dead-space management with vascularized tissue coverage, and culture-directed antimicrobial therapy, typically administered for at least 6 weeks [6]. In chronic or advanced cases characterized by abscess or joint involvement, >50% of patients require operative debridement besides systemic antibiotic therapy [7]. Following extensive debridement of ischial pressure sores complicated by OM, large residual cavities and soft tissue defects frequently persist. Regional muscle flaps provide a reliable option for reconstruction by obliterating dead space, improving local vascularity, and enhancing antibiotic delivery to infected beds. Among such options, the biceps femoris turnover flap has been used for ischial defect reconstruction because of its reliable blood supply, sufficient bulk, and acceptable donor site morbidity [8].

Here, we present a rare case of clinicoradiologically diagnosed symphysis pubis OM secondary to a chronic ischial pressure sore, in which delayed definitive surgical management contributed to the progression of deep infection and exacerbated OM. The patient was successfully treated using aggressive debridement, prolonged culture-directed intravenous (IV) antibiotic therapy, and definitive reconstruction with a biceps femoris turnover flap while preserving pelvic ring stability without radical pubic bone resection. This case highlights the importance of timely surgical intervention in advanced ischial pressure sores and demonstrates the potential role of vascularized muscle flap reconstruction in managing complex pressure sore-related pelvic OM involving the pubic symphysis. The Institutional Review Board of Hallym University Sacred Heart Hospital (IRB No. 2025-12-026) approved this study. The patient provided written informed consent for publication and use of the images.

Case

A 66-year-old man with a 15-year history of complete paraplegia resulting from a fall-related traumatic injury presented with a chronic right ischial pressure sore at our outpatient clinic. Since the onset of paraplegia, the patient had been fully wheelchair-dependent and spent most of the day in a wheelchair for approximately 2 months before presentation.

At the initial outpatient visit, physical examination revealed a 3×3 cm pressure sore in the right ischial area with overlying skin necrosis and adherent slough tissue (Fig. 1). No definite undermining or deep cavity was identified on bedside examination. Due to concerns regarding deep soft tissue infection, the patient was admitted for operative debridement and initiation of IV antibiotic therapy.

Fig. 1

Initial clinical image of the right ischial pressure sore. A 3×3 cm pressure ulcer in the right ischial area with overlying skin necrosis and adherent slough tissue upon initial outpatient evaluation.

Upon admission, laboratory tests revealed a white blood cell count (WBC) of 12,700/μL and C-reactive protein (CRP) levels of 155.48 mg/L, suggesting active inflammation and infection. Initial pelvic CT demonstrated soft tissue involvement without definite evidence of bony involvement (Fig. 2). Wound cultures initially yielded Pseudomonas aeruginosa, and IV piperacillin/tazobactam (4 g/0.5 g every 8 hours) was initiated.

Fig. 2

Initial pelvic computed tomography scan. Soft tissue defect (red arrow) without clear cortical bone destruction demonstrated.

The patient underwent surgical debridement; extensive necrotic soft tissue and devitalized granulation tissue were removed. A 2×7 cm undermined cavity beneath the external defect was identified (Fig. 3). The wound bed was thoroughly irrigated and packed. After initial postoperative laboratory improvement (WBC; 6,500/μL, CRP; 37.05 mg/L), the patient was discharged and readmission was planned for additional debridement and definitive soft tissue coverage. However, the patient’s family declined further surgical intervention, and the patient was followed for 8 months at the outpatient clinic.

Fig. 3

Intraoperative gross image showing an undermined cavity. Intraoperative gross photograph demonstrates a 2×7 cm undermined cavity beneath the external wound opening.

Eight months after initial debridement, follow-up CT revealed ill-defined bone destruction involving the right ischium, inferior pubic ramus, and periarticular bones of the pubic symphysis (Fig. 4). Subsequent pelvic MRI demonstrated a 2-cm periarticular abscess at the superior and inferior portions of the symphysis pubis. This was accompanied by signal changes involving the right ischium and the superior and inferior pubic rami, along with inflammation of the anterior bladder wall and right adductor muscles that tracked toward the cutaneous opening in the right inguinal–ischial region (Fig. 5). These findings were consistent with the progression to OM of the right ischium and pubic bones, complicated by infectious arthritis of the symphysis pubis with associated periarticular abscess formation.

Fig. 4

Follow-up CT scan. (A, B) Follow-up pelvic CT scan done 8 months after initial debridement demonstrates progression of osteomyelitis extending from the right ischium to the inferior pubic ramus (red arrow), suggestive of infectious arthritis of the pubic symphysis. CT, computed tomography.

Fig. 5

Preoperative pelvic MRI. (A) Coronal MRI view demonstrating approximately 2 cm periarticular abscess collections at the superior and inferior portions of the pubic symphysis (red arrow). (B) Axial MRI view demonstrating bone marrow signal changes involving the right ischium and superior and inferior pubic rami (blue arrow), suggestive of contiguous pelvic osteomyelitis. MRI, magnetic resonance imaging.

Further evaluation demonstrated a 7×10-cm undermined cavity, with deep extension toward the symphysis pubis. On examination, the external wound opening measured approximately 3×3 cm, with a large undermined cavity palpable beneath the defect (Fig. 6). The wound contained slough and necrotic tissue, without overt systemic signs of infection.

Fig. 6

Preoperative image of the right ischial wound. A 3×3 cm external wound opening with a 7×10 cm undermined cavity extending deep toward the symphysis pubis.

After explaining the progression of OM to the patient and his family, the clinical team stressed that surgical intervention was necessary. A multidisciplinary discussion was held regarding the extent of the bone resection. Extensive debridement, including the pubic symphysis, was considered; however, it posed a significant risk of disrupting the pelvic ring integrity, which could lead to severe pelvic instability, a critical concern for patients with paraplegia reliant on stable seating for wheelchair mobility. The patient’s family opted for a more conservative approach regarding bony structures. Consequently, the surgical plan was tailored to prioritize radical soft tissue debridement and effective dead-space obliteration using a vascularized flap while limiting bone resection to avoid mechanical complications. The patient was readmitted, and following consultation with infectious disease specialists, IV piperacillin/tazobactam was continued based on deep tissue cultures that yielded Escherichia coli.

Considering the large undermined cavity and need for effective dead-space obliteration with vascularized tissue, an ipsilateral biceps femoris turnover flap was selected. Following radical debridement of all necrotic soft tissues until healthy bleeding tissue was encountered, the cavitary defect was thoroughly irrigated. Intraoperatively, the defect was noted to extend deeply from the ischial region toward the pubic symphysis, with extensive inflammatory and fibrotic soft tissue changes along the contiguous tract. Peri-symphyseal inflammatory tissue corresponding to the preoperative MRI findings were identified and thoroughly debrided. The ipsilateral biceps femoris muscle was harvested while carefully preserving the dominant vascular pedicle to ensure flap viability. The distal portion of the biceps femoris was detached, and the muscle was rotated into the ischial cavity and symphyseal region. This approach enabled tension-free obliteration of the extensive dead space with sufficient bulk and provided a well-vascularized tissue bed over the debrided pelvic region (Fig. 7). Intraoperative tissue cultures obtained near the pubic symphysis yielded Escherichia coli, consistent with the previously identified organism from the wound culture. Consequently, IV piperacillin/tazobactam therapy was administered every 8 hours and maintained for 7 weeks.

Fig. 7

Intraoperative gross image during insetting. Biceps femoris turnover flap (blue arrow) was positioned within the ischial cavity (red arrow) to obliterate dead space and provide coverage over the debrided pubic symphysis region.

Postoperatively, the flap remained well-perfused from postoperative day (POD) 1. The patient was maintained on IV antibiotics, and pressure was avoided at the surgical site with prolonged prone positioning for approximately 6 weeks. On POD 12, the patient’s WBC count and CRP level decreased to 5,900/μL and 11.27 mg/L, respectively, suggesting that the infection was under control. Regular wound care was performed, and the surgical wound healed without complications.

At 8 weeks postoperatively, the patient was discharged with a decreased CRP level of 2.74 mg/L, and no further oral antibiotic therapy was prescribed following consultation with infectious disease specialists. At that time, the external wound completely healed, and the patient was permitted to resume sitting and wheelchair mobility (Fig. 8). Follow-up MRI performed 4 months postoperatively demonstrated interval improvement of OM, with decreased bone marrow signal abnormalities in the right ischium and both pubic bones, improved infectious arthritis of the symphysis pubis, and marked resolution of the previously noted periarticular abscesses (Fig. 9). Overall, the imaging findings were consistent with improvements in pelvic OM and infection control. Regarding functional outcomes, the patient successfully resumed daily activities. By 8 weeks postoperatively, sitting tolerance improved progressively, reaching over 6 hours of daily wheelchair mobility. Three years postoperatively, the patient remained asymptomatic, with no significant discomfort or functional limitation, and continued routine wheelchair mobility without recurrence of the pressure sore or OM.

Fig. 8

Postoperative gross photograph at 8 weeks. Complete wound healing displayed without complications, permitting resumption of sitting and wheelchair mobility.

Fig. 9

Postoperative follow-up MRI. Follow-up MRI performed at 4 months postoperatively demonstrates resolution of periarticular abscess formation at the pubic symphysis (red arrow) (A) and interval improvement of osteomyelitis, with decreased bone marrow signal abnormalities in the right ischium and pubic bones (blue arrow) (B). MRI, magnetic resonance imaging.

Discussion

Pressure sores are a common complication in patients who are wheelchair-dependent or have underlying neurological impairments. Among the various anatomical locations, the ischial region is particularly vulnerable because of sustained pressure and repetitive shear forces during sitting [1]. Ischial pressure sores often present as deep, undermined wounds, and their true extent may be underestimated on initial clinical examination. If appropriately recognized and managed at an early stage, most pressure sores can be treated without progression to deeper infections.

However, if inadequately treated or overlooked, ischial pressure sores may extend into the deeper soft tissues and contiguous bony structures. Chronic infection can lead to ischial OM, and in rare cases, can spread further to the pubic symphysis. Although pubic symphysis OM is rare, its nonspecific clinical presentation can easily lead to a delayed diagnosis [5].

Here, the patient had a history of paraplegia and prolonged wheelchair dependence, predisposing him to the development of an ischial pressure sore. Initial conservative management and limited surgical intervention resulted in temporary laboratory improvements; however, delayed acceptance of definitive surgical treatment allowed the infection to progress. Over time, serial imaging demonstrated progressive pelvic extension of infection from the ischial region toward the pubic symphysis, accompanied by periarticular abscess formation and inflammatory spread into adjacent pelvic soft tissues. These findings suggested advanced contiguous pelvic OM with involvement of the symphyseal region.

Once OM progression was recognized and surgical treatment was accepted, aggressive debridement combined with prolonged culture-directed antibiotic therapy was performed. Adequate source control is essential in established pelvic OM if associated with abscess formation or joint involvement. Following extensive debridement, management of the residual dead space has become a key consideration. Muscle turnover flaps offer several advantages, including dead-space obliteration, improved local perfusion, and enhanced delivery of systemic antibiotics. In the present case, the muscle flap enabled stable obliteration of the extensive cavity extending toward the pubic symphysis while avoiding radical pubic bone resection and preserving pelvic ring stability. This strategy was particularly important for maintenance of long-term seated wheelchair mobility in a paraplegic patient. Here, reconstruction using an ipsilateral biceps femoris turnover flap was performed to eliminate the cavity and provide well-vascularized tissue to the infected bed. The biceps femoris turnover flap offers significant therapeutic value that extends beyond mere structural restoration. The rich microvasculature of the muscle flap transformed the ischemia-infected environment into a well-perfused bed, thereby maximizing the delivery and local concentration of systemic antibiotics directly to the involved bone. Such enhanced vascularization, combined with prolonged culture-directed therapy, enables resolution of pelvic OM without bone resection.

A shortcoming of this report is the absence of direct histopathologic confirmation from the pubic symphysis lesion. However, the diagnosis of OM was established based on a multidisciplinary approach incorporating serial imaging progression, contiguous spread from the chronic ischial wound, periarticular abscess formation, elevated inflammatory markers, and intraoperative findings of deep extension toward the pubic symphysis. Furthermore, the diagnosis was strongly supported by positive tissue cultures (Escherichia coli) obtained from the debrided symphyseal region, and subsequent clinical and radiologic resolution following targeted therapy.

Although this report describes a single case, it illustrates the potential consequences of delayed surgical management in advanced ischial pressure sores and underscores the importance of early recognition of deep infections. The novelty of this case lies in the management of pubic symphysis OM secondary to an ischial pressure sore. While muscle flaps for ischial pressure sores are well-documented, the specific strategy of utilizing a biceps femoris turnover flap to reach the anteriorly located pubic symphysis—without compromising pelvic stability—offers a valuable alternative to more aggressive bone resections. Ultimately, the well-vascularized muscle flap significantly contributed to sustained infection control and long-term wound stability. The patient’s successful return to daily wheelchair mobility, with a sitting tolerance exceeding 6 hours, and the complete absence of recurrence over a 3-year follow-up period, demonstrate the strong therapeutic potential of this approach. This report therefore underscores the therapeutic potential of a well-vascularized muscle flap such as the biceps femoris flap in facilitating the resolution of pelvic OM, when radical bone resection is restricted.

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