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Urethropubic Fistula

Urethropubic fistula — also termed urinary-pubic symphysis fistula (UPF), urosymphyseal fistula, pubosymphyseal fistula, or (when the bladder side dominates) pubovesical fistula — is an abnormal communication between the urinary tract and the pubic symphysis / pubic bone, almost always accompanied by pubic bone osteomyelitis. It is a rare but severely debilitating late complication of pelvic radiation therapy for prostate cancer, typically provoked by endoscopic intervention in an irradiated field — most commonly treatment of a radiation-induced bladder-neck contracture or posterior urethral stenosis. Pelvic-fracture urethral injury (PFUI) with contiguous pubic osteomyelitis is the second classic setting.[1][2][5]

The literature uses several near-synonymous terms for what is fundamentally a spectrum disorder. "Urethropubic" emphasizes the urethra-to-pubis communication; "pubovesical" emphasizes the bladder-to-pubis communication; "urinary-pubic symphysis fistula (UPF)" is the contemporary umbrella term that captures both. The diagnostic workup, imaging, and reconstructive approach are effectively identical across variants — the problem is a hostile, radiated, infected pelvic-bone bed draining urine into the retropubic space, not a specific anatomic subtype.[1][4]

Conservative management fails in the vast majority of post-radiation cases (96% failure rate), and definitive surgical management requires a combination of pubic-bone debridement / partial pubectomy, fistula excision and urinary-tract reconstruction or diversion, vascularized tissue interposition, and pathogen-directed antibiotics for 6+ weeks. Cystectomy with ileal conduit is the most common urinary-management endpoint (53–86%); organ-sparing repair is possible in selected non-radiated cases.[1][2][13][14]

See also: Rectovesical Fistula — Pubovesical Fistula section, PFUI, Bony Pelvic Anatomy, The Retropubic Space, Radiation Tissue Effects, Fistulas landing page.

Epidemiology & Etiology​

Pelvic radiation therapy for prostate cancer is the predominant risk factor, present in 93% of cases in contemporary systematic review.[1] In the largest single-institution series, all patients had received radiotherapy either as primary treatment or after prostatectomy.[2] The fistula typically declares itself a median 4–7 years after radiation (range 1.5–19 years).[3][4][9]

The Endoscopic-Trigger Pathway​

A dominant mechanism threads through most contemporary cases:[2][5]

  1. Prostate cancer treatment (radical prostatectomy ± radiation; primary radiation alone; brachytherapy)
  2. Bladder-neck contracture (BNC) or posterior urethral stenosis develops in the irradiated, ischemic field
  3. Endoscopic intervention — bladder-neck incision, urethral dilation, TURP, holmium laser procedures — attempts to relieve obstruction
  4. Urinary extravasation through the manipulated, radiation-damaged tissue enters the retropubic space
  5. Chronic infection establishes in the pubic bone (osteomyelitis)
  6. Fistula matures between bladder / urethra and pubic symphysis

81–83% of UPF patients have had an endoscopic procedure for bladder outlet obstruction preceding fistula formation.[2][1] Even apparently minor endoscopic maneuvers (single dilation, brief BNC incision) in previously irradiated tissue can precipitate the cascade.[5]

Other Etiologies​

  • Pelvic-fracture urethral injury (PFUI) — contiguous pubic-bone injury with devascularized posterior urethra[7]
  • Radical gynecologic surgery / pelvic exenteration[6]
  • Female incontinence surgery — 24% of a septic-arthritis-of-the-pubic-symphysis series[7]
  • Pelvic malignancy with direct invasion (17% in the same series)[7]
  • Cryotherapy for prostate cancer[2]

Clinical Presentation​

The classic triad is chronic suprapubic / groin / pelvic pain, gait disturbance, and recurrent UTI in a patient with prior pelvic radiation and recent endoscopic manipulation:[2][3][4][7][8]

  • Chronic, debilitating pubic / pelvic / groin pain — 68–100% of patients
  • Difficulty with ambulation or waddling gait — 59%
  • Pain exacerbated by walking
  • Recurrent UTIs
  • Urinary obstruction and urosepsis in advanced cases

The Misdiagnosis Problem​

UPF is commonly misdiagnosed as osteitis pubis — a sterile inflammatory condition — and managed with NSAIDs, activity modification, and empirical antibiotics for months to years before the true diagnosis is made.[2][4] The clinical mimics include septic arthritis of the pubic symphysis, pubic-bone osteonecrosis, and adductor tendinitis. The distinguishing historical features are prior pelvic radiation and recent endoscopic BOO intervention — either of which should prompt immediate MRI.

Diagnosis​

MRI — the Gold Standard​

T2-weighted MRI of the pelvis confirms the diagnosis in 95% of cases.[1][10] Characteristic findings:[10]

  • High signal on T2-weighted sequences in the pubic symphysis and involved pubic rami
  • Low signal on T1-weighted sequences
  • Regional inflammatory myositis in the majority of patients
  • Diastasis of the pubic symphysis
  • Cortical bone erosion
  • Fluid collections — 75% of patients
  • Fistulous tract visualization on dedicated sequences

Combined MRI + Cystoscopy​

The combination of MRI and cystoscopy enables precise characterization of the fistula defect relative to the urinary sphincter complex and the rectum — both critical to operative planning.[1] Findings at cystoscopy suggestive of UPF include bladder-neck sloughing, mucosal necrosis, dystrophic calcification, and cavitation.

Adjunctive Studies​

  • Plain radiography is insensitive — no evidence of osteomyelitis in 63% of cases.[9][10]
  • CT demonstrates bone destruction, abscess, soft-tissue mass, and the fistulous tract, but is less sensitive than MRI.[9]
  • Retrograde urethrography can visualize the fistula and assess for concurrent stricture.
  • CT-guided bone biopsy directs antibiotic management when cultures are needed before surgical debridement.
  • Urine culture frequently grows the same organism later found in bone (63% concordance) and should be obtained preoperatively.[12]

Pathophysiology — UPF as Osteomyelitis​

A key concept from contemporary pathology series: UPF is not just a fistula — it is functionally a pubic-bone osteomyelitis with a fistulous tract feeding urine into the infected bone.[11][12]

Histopathology of Resected Pubic Bone[11]​

Across patients undergoing extirpative surgery:

  • Osteomyelitis present in 88–97% of resected bone specimens
  • Chronic osteomyelitis — 41.7%
  • Combined acute and chronic osteomyelitis — 44.4%
  • Osteonecrosis — 33.6%

Bone Cultures[12]​

91.7% of extirpative specimens produce positive bone cultures. Dominant organisms:

  • Candida — 22%
  • Enterococcus — 18%
  • Pseudomonas — 10%
  • Staphylococcus aureus — common in athletic / non-radiation populations[7]

63% of positive bone cultures grow the same organism identified on preoperative urine culture — supporting empirical antibiotic selection from urine while bone cultures mature.

The operative implication is unambiguous: pubic-bone resection is not optional in UPF with confirmed osteomyelitis — leaving infected bone in place is the dominant reason for recurrence and persistent pain after fistula repair alone.[11]

Management​

Conservative Management — Limited Role​

Conservative management (long-term catheter drainage, suppressive antibiotics, analgesia) fails in 96% of post-radiation UPF and 72% of radiation-naïve UPF.[1] Only 1 of 16 patients in the largest series responded to conservative care.[2]

Conservative management is reasonable only for:

  • Patients who decline surgery
  • Patients too medically compromised for major reconstruction
  • Palliative intent in metastatic cancer recurrence

These patients require long-term suppressive antibiotics and close monitoring for urosepsis.[4]

Definitive Surgical Management — The Four-Element Operation​

Every UPF operation combines four elements:[1][2][4]

  1. Fistulous tract excision
  2. Pubic symphyseal debridement / partial pubectomy — critical given 88–97% histologic osteomyelitis
  3. Vascularized tissue interposition — omental flap, rectus abdominis (VRAM), or gracilis muscle
  4. Urinary-tract reconstruction or diversion

Urinary Management — Reconstruction vs Diversion​

The division between reconstruction and permanent diversion is driven primarily by bladder quality, radiation history, and the extent of fistula involvement at the bladder neck / trigone.

Cystectomy with ileal-conduit diversion — most common approach:[1][2]

  • 53–86% of post-radiation UPF patients
  • Removes the radiated, contracted, infected lower urinary tract in one operation
  • Avoids the substantial recurrence risk of reconstruction in radiated tissue

Bladder-sparing reconstruction — selected patients (14–47%):[1][2]

  • Salvage radical prostatectomy (if prostate still in situ)
  • Substitution or augmentation cystoplasty when bladder capacity is inadequate
  • Requires a compliant, infection-free bladder and motivated patient

Organ-sparing fistula repair with rectus abdominis muscle flap interposition — described in non-radiated or minimally-radiated cases:[13]

  • Kaufman series: rectus abdominis interposition for radiation anterior prostato-symphyseal fistulas with selective success
  • Requires careful patient selection

Robot-Assisted Cystectomy with Holmium Laser Pubic Debridement​

A contemporary minimally invasive approach combining robotic cystectomy with holmium laser debridement of the pubic symphysis has emerged as a less morbid alternative to open pubectomy:[8][14]

Outcomes (Navaratnam series):[14]

  • 91.7% success at median 29-month follow-up
  • Median operative time 270 min
  • Median length of stay 5 days
  • Allows precise, contained debridement of necrotic bone through laparoscopic access

Antibiotic Therapy​

  • Pathogen-directed per bone culture (urine culture can seed initial empirical coverage given 63% concordance)[12]
  • Minimum 6 weeks for osteomyelitis[7]
  • Long-term suppressive antibiotics for patients managed conservatively[4]
  • Infectious-disease co-management is standard given the chronic polymicrobial nature and prolonged duration

Outcomes​

Symptom Resolution​

Immediate and dramatic symptom improvement — particularly resolution of debilitating pain — is the rule after definitive surgical management.[2][15] All patients in major series experienced pain resolution after surgery.[2]

Durability​

Recurrence is rare after appropriate surgical management that includes bone debridement.[8][14] Recurrences cluster in patients where the pubic bone was not adequately resected, re-emphasizing the non-negotiability of debridement.

Morbidity and Recovery​

The operation carries high morbidity and prolonged recovery:[2]

  • Prolonged hospital length of stay
  • Significant blood loss in open cases
  • Wound and stoma complications
  • Prolonged convalescence
  • Postoperative requirement for urinary stoma care (when cystectomy performed)

Pelvic Ring Stability​

An important reassurance — no pelvic ring instability has been reported following pubic bone resection in UPF series.[4] The sacroiliac joints and posterior pelvic ring are sufficient to maintain gait and load-bearing function after partial pubectomy.

Prevention​

Given the dominant etiologic pathway (radiation → BNC → endoscopic BOO treatment → UPF), prevention focuses on the third step:[5]

  • Exercise restraint with endoscopic intervention in radiated patients — accept higher thresholds for proceeding to BNC incision, dilation, or TURP.
  • Prefer the least traumatic option when intervention is necessary — single gentle dilation over aggressive incision or TURP.
  • Inform patients of the UPF risk before any endoscopic manipulation in a radiated pelvis.
  • Early imaging (MRI) when any radiated patient with prior BOO treatment develops new pubic or groin pain — do not dismiss as osteitis pubis.

Clinical Pearls​

  • High index of suspicion in irradiated patients presenting with pubic pain, gait disturbance, and recurrent UTI — especially after any endoscopic BOO procedure.[1][2]
  • MRI pelvis should be obtained promptly when UPF is suspected — plain films are insensitive.[10]
  • Multidisciplinary team: reconstructive urology + infectious disease + orthopedic or plastic surgery (for flap).[4][12]
  • Pubic-bone resection is mandatory at definitive surgery — 88–97% histologic osteomyelitis means residual infected bone drives recurrence.[11]
  • Counsel patients toward permanent diversion (ileal conduit) as the default urinary-management endpoint in radiated disease — bladder-sparing is the exception, not the rule.[1][2]
  • Even minimally traumatic endoscopic procedures in previously irradiated tissue can precipitate UPF — there is no "safe" endoscopic intervention in a radiated posterior urethra.[5]
  • Symptom relief is dramatic after successful surgery — this reframes the operation for patients weighing high morbidity against debilitating chronic pain.[2][15]

References​

1. Patel N, Mehawed G, Dunglison N, et al. Uro-Symphyseal Fistula: A Systematic Review to Inform a Contemporary, Evidence-Based Management Framework. Urology. 2023;178:1–8. doi:10.1016/j.urology.2023.05.002

2. Bugeja S, Andrich DE, Mundy AR. Fistulation Into the Pubic Symphysis After Treatment of Prostate Cancer: An Important and Surgically Correctable Complication. Journal of Urology. 2016;195(2):391–398. doi:10.1016/j.juro.2015.08.074

3. Walach MT, Tavakoli AA, Thater G, et al. Pubic Bone Osteomyelitis and Fistulas After Radiation Therapy of the Pelvic Region: Patient-Reported Outcomes and Urological Management of a Rare but Serious Complication. World Journal of Urology. 2024;42(1):461. doi:10.1007/s00345-024-05155-2

4. Gupta S, Zura RD, Hendershot EF, Peterson AC. Pubic Symphysis Osteomyelitis in the Prostate Cancer Survivor: Clinical Presentation, Evaluation, and Management. Urology. 2015;85(3):684–690. doi:10.1016/j.urology.2014.11.020

5. Shapiro DD, Goodspeed DC, Bushman W. Urosymphyseal Fistulas Resulting From Endoscopic Treatment of Radiation-Induced Posterior Urethral Strictures. Urology. 2018;114:207–211. doi:10.1016/j.urology.2017.12.020

6. Hoyme UB, Tamimi HK, Eschenbach DA, Ramsey PG, Figge DC. Osteomyelitis Pubis After Radical Gynecologic Operations. Obstetrics and Gynecology. 1984;63(3 Suppl):47S–53S.

7. Ross JJ, Hu LT. Septic Arthritis of the Pubic Symphysis: Review of 100 Cases. Medicine. 2003;82(5):340–345. doi:10.1097/01.md.0000091180.93122.1c

8. Hebert KJ, Boswell TC, Bearrick E, et al. Robotic Puboprostatic Fistula Repair With Holmium Laser Pubic Debridement. Urology. 2022;160:228. doi:10.1016/j.urology.2021.10.019

9. Wignall TA, Carrington BM, Logue JP. Post-Radiotherapy Osteomyelitis of the Symphysis Pubis: Computed Tomographic Features. Clinical Radiology. 1998;53(2):126–130. doi:10.1016/s0009-9260(98)80059-7

10. Sexton SJ, Lavien G, Said N, et al. Magnetic Resonance Imaging Features of Pubic Symphysis Urinary Fistula With Pubic Bone Osteomyelitis in the Treated Prostate Cancer Patient. Abdominal Radiology. 2019;44(4):1453–1460. doi:10.1007/s00261-018-1827-2

11. Kahokehr AA, Boysen WR, Schild MH, et al. Urinary Pubic Symphysis Fistula Leads to Histopathologic Osteomyelitis in Prostate Cancer Survivors. Urology. 2021;148:297–301. doi:10.1016/j.urology.2020.07.038

12. Nosé BD, Boysen WR, Kahokehr AA, et al. Extirpative Cultures Reveal Infectious Pubic Bone Osteomyelitis in Prostate Cancer Survivors With Urinary-Pubic Symphysis Fistulae (UPF). Urology. 2020;142:221–225. doi:10.1016/j.urology.2020.04.095

13. Kaufman DA, Browne BM, Zinman LN, Vanni AJ. Management of Radiation Anterior Prostato-Symphyseal Fistulas With Interposition Rectus Abdominis Muscle Flap. Urology. 2016;92:122–126. doi:10.1016/j.urology.2016.01.029

14. Navaratnam A, Faraj K, Rose K, et al. Robot Assisted Cystectomy With Holmium Laser Debridement for Osteomyelitis of the Pubic Symphysis With Urinary Fistula. Urology. 2019;134:124–134. doi:10.1016/j.urology.2019.08.049

15. Devlieger B, Wagner D, Hopf J, Rommens PM. Surgical Debridement of Infected Pubic Symphysitis Supports Optimal Outcome. Archives of Orthopaedic and Trauma Surgery. 2021;141(11):1835–1843. doi:10.1007/s00402-020-03563-8