EP1092 - Perineal approach for repair of a radiation-induced prostatorectal fistula with gracilis flap

Purpose/Background: 46-year-old male with history of prostate cancer treated with androgen deprivation and stereotactic body radiation. He subsequently developed urinary retention, pneumaturia, and fecaluria. At another institution, he was diagnosed with a prostatorectal fistula via cystoscopy and retrograde urethrogram. He was initially managed with a suprapubic catheter and sigmoid diverting ostomy.

Methods/Interventions: The patient was taken to the operating room and placed in lithotomy. On digital rectal exam, a divot was palpable on the anterior rectum 4 cm above the anal verge. Flexible sigmoidoscopy was performed to the patient's ostomy; this did not reveal a clear fistula. Concurrent cystoscopy did reveal a patent opening on the urethra proximal to the verumontanum suggestive of a prostatorectal fistula. While this was not traversable with a wire, catheter-guided injection of methylene blue did stain the rectum blue. Next, a Mercedes-type incision along the perineum and around the rectum was made. The dissection was extended down to the urethra and a Lone Star retractor was placed. There were dense radiation-induced fibrotic changes, these were divided sharply and the dissection continued past the central tendon and onto the rectourethralis muscle. A particularly thick band of fibrosis was identified at this point which was suspicious for the fistula. Repeat cystoscopy confirmed this, the band was divided revealing more clearly the anterior rectal wall defect. This was repaired with 0-Vicryl figure-of-eight stitches and a second layer of Lemberted 2-0 PDS. The repair was submerged with saline and after insufflation of the rectum, no bubbles were noted. Then, the urology team excised the fistula completely and repaired the prostatic urethra with Monocryl. Their repair was tested by injecting saline through the urethra which showed no leaks. Gracilis muscle was harvested from the left leg, tunneled into the perineum and interposed between the prostate and rectum. The wounds were irrigated and closed in layers leaving quarter-inch Penrose drains in place. A suprapubic catheter and a Foley catheter were also placed.

Results/Outcomes: On postop day 5, the patient developed fevers and purulent drainage from the Penrose drains. The perineal incision was partially opened for drainage, he was treated with negative pressure wound therapy (NPWT), then transitioned to wet to dry dressings with Vashe. He returned to the OR for wound washout on postop day 11 and was discharged with home health for continued NPWT. Contrast enema will be performed 8 weeks postop to evaluate rectal fistula repair.

Conclusion/Discussion: Repair of iatrogenic fistulas following radiation for treatment of prostate cancer is complex, multiple approaches have been described but there is no consensus regarding best management for these. These often require multidisciplinary approach, such as in this case in which urologic and colorectal surgeons repaired a fistula from the prostatic urethra into the rectum via a perineal approach using a gracilis muscle flap.

Figure 1
(A) Cystoscopy revealing fistula opening in prostatic urethra. (B) Extravasation of contrast into rectum on retrograde urethrogram. Operative picture of perineal exposure for fistula repair with prostate retracted anteriorly to reveal defect on anterior rectal wall visible, before (C) and after repair (D).