Schematic model.

Operative animation, York-Mason fistula repair

York-Mason repair: a rectourethral fistula through the sphincters

Repair, from behind with the patient prone, of a small rectourethral fistula after radical prostatectomy. The sphincter muscles and the posterior rectal wall are divided in the midline so that the fistula is seen directly on the anterior rectal wall.

The track is excised, the urethra and the rectum are closed separately, and every divided layer is brought back to its own partner. The lesson is the order of the layers, the pairs that mark them, and three suture lines of which none lies along another.

Advanced tier FRCS urethral reconstruction, complications of radical prostatectomy Interactive 3D
Schematic scene preview: York-Mason fistula repair
Preparing the 3D anatomy…

UrOops3D · UroRef · © Nity G

How to use this module. Play through the nine steps, or use Back and Next. The card in the corner says how the patient lies and which way the view looks. Watch each layer take its coloured pair, the track leave whole, and the knots tied deepest first. The triggers show a stricture, a recurrence and a misjoined layer.

Click me next Section 2 of 8 Anatomy The structures this operation works between, and the one it must not cross.

The structures in the scene

York-Mason fistula repair: how the structures relateProne, from behind: what is divided to reach the fistula, and what lies in front of it. Fistula on the anterior rectal wall: track runs to it; separated, closed in one layer Urethra and anastomosis, just in front (danger). Fistula on the anterior rectal wall: divided first to reach it; marked with a pair External anal sphincter (danger). Fistula on the anterior rectal wall: divided next; marked with its own pair Puborectalis and levator plate (danger). Fistula on the anterior rectal wall: divided last; tied first on the way out Internal anal sphincter (danger). Fistula on the anterior rectal wall: opened lengthwise to see it from inside Posterior rectal wall. Fistula on the anterior rectal wall: incision runs from here to the anal verge Coccyx: top of the incision.Fistula on the anteriorrectal wall!Urethra andanastomosis, just infront!External analsphincter!Puborectalis andlevator plate!Internal analsphincterPosterior rectalwallCoccyx: top of theincisiontrack runs to it;separated, closedin one layerdivided first toreach it; markedwith a pairdivided next;marked with its ownpairdivided last; tiedfirst on the wayoutopened lengthwiseto see it frominsideincision runs fromhere to the analvergeTargetDangerLandmarkContext
Prone, from behind: what is divided to reach the fistula, and what lies in front of it. Schematic, not to scale; relationships only.
  • With the patient prone and jackknifed, the surgeon looks at the natal cleft from behind: coccyx above, anus below, the patient's left on the left.
  • Under the skin lie the external sphincter round the canal and, above it, the puborectalis and the levator plate running up to the coccyx.
  • Deep to those is the internal sphincter and the posterior rectal wall.
  • Through the opened rectum the anterior wall faces the surgeon, with the urethra and the anastomosis immediately beyond it.
  • ›Coccyx and anal verge - the two ends of the incision; with the patient prone the coccyx is at the top of the field.
  • ›External anal sphincter - the outermost muscle round the anal canal; divided and marked with its own pair.
  • ›Puborectalis and levator plate - the sling behind the anorectal junction and the sheet running up to the coccyx; divided and marked.
  • ›Internal anal sphincter - the deepest muscular layer of the canal, continuous with the rectal muscle above; divided and marked.
  • ›Posterior rectal wall - opened lengthwise to see the anterior wall from inside; closed in two layers.
  • ›Anterior rectal wall - carries the rectal end of the fistula; closed in two layers at right angles.
  • ›Fistulous track - from the vesicourethral anastomosis to the rectum; excised whole with the inflammatory tissue round it.
  • ›Urethra and anastomosis - directly in front of the rectum; separated from it and closed in one layer over the catheter.
  • ›Presacral fascia - the drain lies beneath it and leaves through its own stab incision.
Click me next Section 3 of 8 Steps The operation in order, with the landmark that guards each move.

Operative steps

  1. Cystoscopy and a catheter through the fistula A man with a small rectourethral fistula after radical prostatectomy. Antibiotics are given. Supine, a cystoscope is passed and the fistula is identified at the bladder neck. A small open-ended catheter is passed through the fistula into the rectum. The cystoscope is removed and replaced with a urethral catheter on a drainage bag.
    where it bites: the catheter through the fistula is how it will be found from behind; without it a small opening is easy to miss.
  2. Prone jackknife and the incision The patient is turned prone on two chest rolls with the arms overhead, and the table is flexed fully so the hips are raised and the head and body are lowered. Every pressure point is padded and the patient is secured to the table. The lower back, the buttocks and the upper thighs are prepared. A vertical incision is made from the coccyx to the anal verge and taken through the subcutaneous tissue with diathermy. A self-retaining retractor is placed.
    where it bites: a prone, flexed patient is at risk at every pressure point; padding and fixation are checked before the drapes go on.
  3. Divide the sphincters, layer by layer The posterior anal sphincter is identified. Its muscular layers are divided individually in the midline, layer by layer. Paired sutures are placed systematically at each level to make the later realignment possible.
    where it bites: a layer divided without its pair cannot be matched to its partner at the end; the pairs are what make an accurate repair possible.
  4. Open the posterior rectal wall The posterior rectal wall is exposed, incised longitudinally in the midline and retracted laterally. The open-ended catheter is identified coming out of the fistula on the anterior rectal wall.
    where it bites: the opening is kept central; an incision that strays lateral leaves the muscle unequal on the two sides.
  5. Excise the fistula, separate the urethra The fistula is dissected circumferentially and mobilised proximally. The entire fistulous track and the inflammatory tissue round it are excised, and the open-ended catheter is removed. The urethra is separated further from the rectal wall by sharp dissection.
    where it bites: the urethra and the anastomosis lie directly in front; the dissection is sharp, under vision, and takes no more urethral wall than the track.
  6. Close the urethra The urethra is closed with a running absorbable suture over the urethral catheter that was placed at the start.
    where it bites: bites that take too much wall narrow the lumen; the catheter is the guide to its calibre.
  7. Close the anterior rectal wall in two layers The anterior rectal wall is closed in two layers at right angles to each other, with interrupted absorbable sutures. The deep layer takes the rectal muscle and the submucosa. The superficial layer brings the anterior rectal mucosa over the first, overlapping it in the vest-over-pants manner.
    where it bites: suture lines that lie along one another invite a recurrence.
  8. Posterior wall, then the sphincters by their pairs The posterior rectal wall is closed in two layers of running absorbable suture. The anal sphincter sutures placed earlier are then tied individually, which restores the muscle layers anatomically.
    where it bites: a pair tied to the wrong partner leaves a step in the ring.
  9. Drain and closure A surgical drain is positioned under the presacral fascia, brought out through a separate stab incision and secured at the skin. The subcutaneous layer is closed with a running suture and the skin with interrupted sutures. A dressing is applied and the patient is turned supine. The urethral catheter is kept in.
    where it bites: the catheter protects the urethral closure; it is secured so that it cannot be pulled.
Click me next Section 4 of 8 Danger zones Where this operation bites, and why it bites there.
Critical relationship

Danger zones

The spatial relationships the animation is built to make automatic. Before you read each one, ask yourself: at this point in the operation, what is about to go wrong, and what is my first move? The save for each sits in the Complications tab.

  • RiskThe sphincter layers - each is divided and marked with a pair before the next is cut.
  • RiskUrethra and anastomosis - in front of the rectal wall at the fistula; separated by sharp dissection and closed without narrowing.
  • RiskClosures that overlie - the urethral row and the deep rectal row cross at a right angle; the mucosal row lies below both.
  • RiskThe anal canal - laid open and rebuilt; narrowing of the canal afterwards is a recognised risk.
  • RiskPressure areas - prone jackknife for the whole operation: chest rolls, padded limbs, secure fixation.
Practise it Take me into the scene Opens the animation at a danger moment and asks you to predict the mechanism and your first move before it reveals.
Click me next Section 5 of 8 Complications The save for each one: the first move, the escalation trigger, the op-note line.

Complications and immediate saves

Trigger each of these live in the Animation tab, then read the save: the first move, the escalation trigger, and the line that goes in the op note.

Urethral stricture

  • the urethra heals narrow at the closure; urethral stricture is on the list of complications for this repair.
The save
  1. A poor stream after the catheter comes out is assessed, not instrumented blind: flow rate, residual volume, then a urethrogram or a flexible cystoscopy. first move
  2. Retention is relieved with a suprapubic catheter if a urethral catheter does not pass easily; no force through a fresh repair.
  3. A stricture beside a healed fistula repair is referred to a reconstructive urologist. escalation trigger
  4. Imaging checks that the fistula itself has stayed closed before anything is done to the stricture.
  5. Notes: the level and length of the narrowing, how it was shown and what was done about drainage. document

Recurrent fistula

  • urine in the rectum, or air or faeces in the urine, after the repair; a recurrent or persistent fistula is a listed complication of this operation.
The save
  1. Urinary drainage is kept or replaced, and the fistula is confirmed with a contrast study or endoscopy. first move
  2. Sepsis is treated and the bowel rested; a defunctioning stoma is discussed with the colorectal team if one is not already there.
  3. A fistula that persists is referred for a planned re-repair by a team that does this work; a repair with interposed tissue is the usual next step. escalation trigger
  4. No second attempt through inflamed tissue in the first weeks.
  5. Notes: how the recurrence was shown, the drainage in place and the referral made; the patient is told plainly. document

Faecal incontinence

  • loss of control of flatus or stool after the sphincters have been divided and repaired; a recognised risk of the approach.
The save
  1. In theatre, a layer that does not sit level is not accepted: the pair is cut and each layer is matched again to its own partner. first move
  2. After the operation, control of flatus, liquid and solid stool is asked about at each visit, and the anal canal is examined.
  3. Persisting incontinence goes to the colorectal team for assessment of the sphincter, with endoanal imaging and physiology as they advise. escalation trigger
  4. A stoma is not closed until continence and the repair have both been assessed.
  5. Op note: each layer divided, the pair placed on it and the order of tying. document
Click me next Section 6 of 8 Troubleshooting When the case turns: the problem, then the next move.

Intra-operative troubleshooting

When the case turns: the problem, then the next move.

  • ActionThe fistula is hard to find from the rectal side - the open-ended catheter passed at cystoscopy is the marker; it is looked for coming out of the anterior rectal wall. A colonoscopy at the start of the operation, as well as the cystoscopy, is a described variation.
  • ActionThe exposure is too tight at the upper end - the incision can be extended upward to the left of the coccyx for a better view.
  • ActionThe bowel has not been defunctioned - faecal diversion may be performed at the time of the repair; it is a decision made with the colorectal team before the patient is positioned.
  • ActionThere is a urethral stricture as well as the fistula - the described alternative is an anterior transsphincteric approach with the patient in lithotomy, so that both can be dealt with.
  • ActionThe fistula is large, or the pelvis has been irradiated - this operation is described for small, post-surgical fistulas. In the published review most repairs were transperineal, most used a tissue flap between the closures, and most of the larger centres did both in every case.
  • ActionA layer does not come together level when its pair is tied - the pair is cut and the two ends are identified again before retying; the next layer is not tied over a step.
Click me next Section 7 of 8 FRCS viva Say it out loud, then mark yourself against the model answer.

FRCS viva questions

The examiner stems this scene prepares you for. Try to answer out loud first, then reveal, and learn the discriminator, the detail that turns a pass into a strong pass.

QA man has a rectourethral fistula after radical prostatectomy that has not closed on a catheter. What are the options, and where does the York-Mason repair fit?reveal answer
  • I would first define the fistula: its size and level at cystoscopy and on imaging, whether the pelvis has been irradiated or ablated, whether there is a urethral stricture, and whether the bowel is defunctioned.
  • The systematic review by Hechenbleikner and colleagues is the summary I would quote.
  • It found 26 retrospective series with 416 patients, 40 per cent of whom had had pelvic irradiation or ablation.
  • Nine in ten had one of four kinds of repair: transperineal in 65.9 per cent, transsphincteric in 15.7 per cent, transabdominal in 12.5 per cent and transanal in 5.9 per cent.
  • Tissue interposition flaps, mostly gracilis, were used in 72 per cent, the fistula was closed in 87.5 per cent, and most of the larger centres used a transperineal repair with a flap in every case.
  • The authors point out that the series are retrospective and each reflects the approach its centre prefers.
  • Against that background I would offer the York-Mason repair to a man with a small fistula after surgery alone, which is the described indication, and I would refer the large, irradiated or recurrent fistula for a transperineal repair with interposed tissue.
  • I would do it jointly with a colorectal surgeon.
Strong pass

Selecting by fistula

Examiner note
Selecting by fistula: small and post-surgical for the posterior approach; irradiated, large or recurrent for a transperineal repair with a flap, which is what most of the published repairs were.
QTalk me through the York-Mason repair.reveal answer
  • I would give antibiotics and start supine with a cystoscopy: I identify the fistula at the bladder neck, pass a small open-ended catheter through it into the rectum and leave a urethral catheter.
  • I then turn the patient prone on chest rolls and flex the table into the jackknife position, padded and secured.
  • I make a vertical incision from the coccyx to the anal verge, take it through the subcutaneous tissue with diathermy and place a self-retaining retractor.
  • I identify the posterior sphincter and divide its muscular layers one at a time down the middle, placing a pair of sutures on each layer as I divide it.
  • I open the posterior rectal wall lengthwise and retract it, and I find the catheter coming out of the anterior wall.
  • I dissect the fistula all round, excise the whole track with the inflamed tissue and remove the small catheter.
  • I separate the urethra from the rectal wall sharply and close it with a running stitch over the urethral catheter.
  • I close the anterior rectal wall in two layers at right angles: muscle and submucosa first, then the mucosa overlapped over that row.
  • I close the posterior wall in two running layers and tie the sphincter pairs one by one.
  • I leave a drain under the presacral fascia through a separate stab, close the wound and keep the urethral catheter.
Strong pass

Say both

  • The pairs: each layer marked as it is divided and tied to its own partner at the end
  • With the anterior closure in separate layers whose rows cross or are stepped
Examiner note
The pairs: each layer marked as it is divided and tied to its own partner at the end, with the anterior closure in separate layers whose rows cross or are stepped.
QWhat does dividing the sphincters cost the patient, and what are the results of this operation?reveal answer
  • I would tell him the recognised complications: infection, faecal or urinary incontinence, a recurrent or persistent fistula, increased flatulence, anal stenosis and urethral stricture.
  • I would quote two series.
  • Dafnis reported 20 consecutive patients treated with a modified York-Mason repair in one Swedish hospital over 15 years: 18 were repaired successfully, with no recurrence in those 18 at a median of 84.7 months, and all 13 whose stoma had been closed reported intact faecal continence and no anal stenosis.
  • Every patient in that series had a diverting stoma, 12 before the repair and 8 at the same operation.
  • Van der Graaf and colleagues reported 12 fistulas after robot-assisted prostatectomy from one Dutch centre: in the 8 men who had had surgery alone and had the York-Mason repair as their first operation, all were closed at a median of 5.1 years.
  • These are small, single-centre, selected series, so I would present them as what experienced units have achieved and not as his own odds.
Strong pass

Say all four

  • Quoting the series as series: small
  • Single-centre and selected
  • All of the Swedish patients defunctioned
  • The best results in non-irradiated men at their first repair
Examiner note
Quoting the series as series: small, single-centre and selected, all of the Swedish patients defunctioned, and the best results in non-irradiated men at their first repair.
QThree weeks after the repair he passes urine through the rectum again. What do you do?reveal answer
  • I would treat it as a recurrent fistula until shown otherwise.
  • I would make sure the bladder is drained, by leaving or replacing the urethral catheter or with a suprapubic catheter, treat any sepsis and confirm the fistula with a contrast study and endoscopy.
  • I would discuss a defunctioning stoma with the colorectal team if he does not have one.
  • I would not go back through inflamed tissue early.
  • Once things have settled I would refer him for a planned re-repair by a team that does this regularly.
  • In the review by Hechenbleikner and colleagues most repairs used an interposition flap, mostly gracilis, and the European guideline on urethral strictures, writing about fistulas with posterior urethral injury, advises a local tissue flap to separate the suture lines after a rectourethral fistula is corrected.
  • So I would expect the second operation to put healthy tissue between the urethra and the rectum.
  • I would record how the recurrence was shown and what I told him.
Strong pass

Say all three

  • Drainage and control of sepsis first
  • No early re-operation
  • A re-repair that interposes healthy tissue between the two closures
Examiner note
Drainage and control of sepsis first, no early re-operation, and a re-repair that interposes healthy tissue between the two closures.
Click me next Section 8 of 8 Evidence The guidance each of these answers is built on.

Evidence and guidance

Operative Dictations in Urologic Surgery
Armenakas NA, Fracchia JA, Golan R. Transsphincteric rectourethral fistula repair (York-Mason procedure). Chapter 65. Wiley, 2019
The indication (small, post-surgical rectourethral fistulas), the nine essential steps and their order, the template dictation followed step by step here, the variations (colonoscopy at the start, faecal diversion at the time of the repair, the incision extended to the left of the coccyx, an anterior transsphincteric approach in lithotomy when there is a stricture) and the complication list: infection, faecal or urinary incontinence, recurrent or persistent fistula, increased flatulence, anal stenosis, urethral stricture. The chapter does not name the muscular layers; the three drawn (external sphincter, puborectalis with the levator plate, internal sphincter) are standard anatomy, with one pair shown on each. It says the two anterior layers are perpendicular without saying which way each lies; the scene puts the deep row along the rectum and the mucosal row across it. The scene is schematic. The chapter lists complications without their management: the first, escalate and document steps and the danger lines are general surgical practice. The faecal incontinence picture (a layer tied to the wrong partner) illustrates why the pairs are placed; the chapter gives no mechanism for incontinence.
Open guideline
Diseases of the Colon and Rectum
Hechenbleikner EM, Buckley JC, Wick EC. Acquired rectourethral fistulas in adults: a systematic review of surgical repair techniques and outcomes. Dis Colon Rectum 2013;56:374-383
Abstract read 13 October 2026. Twenty-six retrospective series, 416 patients, 169 (40%) with previous pelvic irradiation or ablation. Nine in ten patients had one of four kinds of repair: transanal 5.9%, transabdominal 12.5%, transsphincteric 15.7%, transperineal 65.9%. Interposition flaps, predominantly gracilis, in 72%; fistula closed in 87.5%; permanent faecal diversion 10.6% and urinary diversion 8.3%. Most high-volume centres used transperineal repair with a flap in every case. The authors note heterogeneity and bias toward the approach each centre prefers.
Open guideline
International Journal of Urology
Dafnis G. Transsphincteric repair of rectourethral fistulas: 15 years of experience with the York Mason approach. Int J Urol 2018;25:290-296
Abstract read 13 October 2026. Twenty consecutive patients, one hospital, 2002 to 2016, a modified York Mason technique: 18 repaired successfully, no recurrence in those 18 at a median of 84.7 months; 12 had a diverting stoma before the repair and 8 at the repair; all 13 whose stoma had been closed reported intact faecal continence and no anal stenosis. Diabetes, smoking and preoperative irradiation were more frequent in the two failures, without a significant difference.
Open guideline
World Journal of Urology
van der Graaf SH et al. Management in robot-assisted radical prostatectomy patients with recto-urethral fistulas: the York-Mason technique. World J Urol 2025;43:604
Abstract read 13 October 2026. Single-centre retrospective cohort, 2011 to 2024: 12 fistulas after robot-assisted prostatectomy, all treated with the York-Mason technique after catheter drainage had failed. Of 10 men with surgery alone, 8 had it as their first operation and all 8 were closed at a median follow-up of 5.1 years. The authors conclude that it works best as the first surgical intervention in men without salvage radiotherapy.
Open guideline
Case Reports in Urology
Yetişir F et al. Management of recurrent rectourethral fistula by York Mason posterior transrectal transsphincteric approach. Case Rep Urol 2015;2015:854365
Full text read 13 October 2026. A single case, used only for its description of the technique: the internal and external sphincters and the puborectalis identified with sutures and incised, the posterior rectal wall opened, the urethral and rectal walls separated sharply, the urethra closed, the anterior rectal wall closed with an advancement flap of mucosa from above, and the sphincter structures repaired one by one by the sutures placed at the start. No figure is taken from it.
Open guideline
EAU Guidelines
Urethral Strictures, 2026: Disease management in males, sections 6.3.5.b.2.a.1 and 6.3.5.b.2.b, read 13 October 2026
Context only. The guideline has no section on the York-Mason repair. In post-traumatic posterior urethral stenosis it says interposition flaps are useful to separate the suture lines when there is a concomitant rectourethral fistula, and recommends a local tissue flap after correction of a concomitant rectourethral fistula (weak). Used for the principle of separating suture lines, in the recurrence answer.
Open guideline

Curriculum. Supports learning relevant to the ISCP Urology Curriculum syllabus topics Prostate cancer and Urethral reconstruction. Not a workplace-based assessment and not evidence of competence.

Two minutes

Close the lap: recall it before you leave.

Say it aloud, then reveal. Reading is not remembering.

  1. 01 The relationship Say the critical spatial relationship out loud, then reveal. reveal
    Memory frame

    With the patient prone and jackknifed, the surgeon looks at the natal cleft from behind: coccyx above, anus below, the patient's left on the left.

    Why?
    Under the skin lie the external sphincter round the canal and, above it, the puborectalis and the levator plate running up to the coccyx. Deep to those is the internal sphincter and the posterior rectal wall. Through the opened rectum the anterior wall faces the surgeon, with the urethra and the anastomosis immediately beyond it.
  2. 02 The first move Urethral stricture. Your first move? reveal
    First move

    A poor stream after the catheter comes out is assessed, not instrumented blind: flow rate, residual volume, then a urethrogram or a flexible cystoscopy.

  3. 03 The escalation trigger Urethral stricture. What makes you call for help? reveal
    Escalate when

    A stricture beside a healed fistula repair is referred to a reconstructive urologist.

  4. 04 The discriminator What turns a pass into a strong pass? reveal
    Strong pass

    Selecting by fistula

    Examiner note
    Selecting by fistula: small and post-surgical for the posterior approach; irradiated, large or recurrent for a transperineal repair with a flap, which is what most of the published repairs were.
  5. 05 The pitfall Where does this operation bite first? reveal
    Pitfall

    The sphincter layers

    Why?
    each is divided and marked with a pair before the next is cut.

Revision practice with self-marked answers, not an assessment of clinical competence. Kept in this browser only; it does not sync between devices.