Tricks - Imperforate Anus and Rectourethral Fistula

In rectourethral fistula repair, dissection must extend to the 'red line' to prevent residual fistula without injuring nerves, prostate, urethra, and sphincters.

A novel technique allows measurement of fistula length intraoperatively, enabling the surgeon to know exactly how far to safely dissect distally for complete cyst excision.

In the case series, 23 of 29 male patients with imperforate anus had rectourethral fistulas (1 vesical, 14 prostatic, 9 bulbar, 5 no fistula).

During laparoscopic dissection, a fine flexible colonoscope inserted into the anterior rectal wall allows observation of both the fistula orifice and the level of dissection intraluminally.

A fine catheter with calibration is inserted through the fistula opening by the laparoscopic surgeon while another surgeon performing cystoscopy observes how far it emerges at or near the verumontanum, allowing measurement of the inside length of the fistula.

If the length of the residual fistula is longer than 5 millimeters, the rectal end is further dissected toward the urethra using mucosectomy to prevent injury to the prostate and urethra.

The measurement and dissection procedure is repeated until the length of the residual fistula is shorter than or equal to 5 millimeters, then the fistula is ligated, tied, and excised.

For bulbar fistula repair, it is very important to obtain a clear surgical field of the deep pelvic floor; this is achieved through suprapubic tube cystostomy which decompresses the bladder and opens up a clear view.

Trocar position for bulbar fistula differs from prostatic fistula in that right and left trocars are placed much closer to the telescope, which is key for bulbar fistula repair.

Despite increased difficulty in handling forceps in the closer trocar position, it allows the tips to reach deeper and access the bulbar urethra located deep in the pelvis.

After the fistula is tied, a catheter is again inserted until it gently probes the tied fistula, allowing the surgeon to reconfirm that the residual fistula length is shorter than or equal to 5 millimeters (around 2-3 millimeters).

In the first eight cases, initial measurements of fistula length from rectal to urethral orifice were 13, 15, 12, 10, 15, 21, 10, and 5 millimeters respectively; seven cases required further dissection until the fistula was ≤5 mm, but case 8 did not require further dissection.

During cystoscopy, normal saline refluxed into the pelvic floor through the fistula in 6 cases (indicating a large fistula), but there was no reflux in 2 cases (indicating a very narrow fistula).

All 23 patients were well after mean follow-up of 2 years, with no evidence of diverticular formation owing to residual fistula on voiding urethrography or MRI.

All dissections were uncomplicated and postoperative courses were unremarkable.

The residual fistula from rectal site to urethral site is much longer than expected.

The new technique of measuring exact fistula length facilitates safe and complete excision of the fistula, reducing the risk of postoperative diverticulum formation due to incomplete fistula excision.

The speaker prefers right transverse colostomy because sigmoid colostomy can fix the rectum and colon, requiring takedown of the sigmoid colostomy to achieve adequate length for pull-through.

For thoracoscopic TEF repair, the speaker checks the gap length between proximal and distal esophagus using bronchoscopy to locate the fistula orifice, then takes an X-ray with the bronchoscope in position to measure the gap (in this case, approximately one vertebra).

The speaker does not divide the distal esophagus completely during TEF repair, leaving one-quarter of the fistula uncut to prevent cranial retraction of the distal esophagus and to facilitate anastomosis.

Leaving one-quarter of the fistula uncut provides fixation of the distal esophagus, making it easier to grasp the mucosa during anastomosis.

For the proximal esophagus, the speaker leaves 12-15% of the tip uncut (a 'cap') to provide a handle for grasping with forceps, avoiding trauma to the anastomotic site.

If there is a 1-2 to 3 vertebra gap, an assistant can pull the proximal esophagus caudally using the uncut cap of the proximal esophagus.

The speaker places the first anastomotic stitch in the middle of the posterior wall rather than at the edge.

The speaker divides the tracheoesophageal fistula completely only after placing 1-2 stitches, and divides the uncut cap of the proximal esophagus after 2-3 stitches.

By using this technique, the surgeon virtually does not touch the anastomotic site in the proximal and distal esophagus.

If the fistula is clipped very tightly, it will erode the muscle of the esophagus and cause recurrence; the clip should just oppose the tissue rather than crush it.