Colorectal Quiz: Episode 43 - Malone Problems
With Dr. Jeffrey Avanzino · hosted by Dr. Felipe Glus
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What the experts said
The patient is a 21-year-old male with imperforate anus without fistula, no Down syndrome, developmentally typical, repaired in 2001, with history of tethered cord repair.
The patient underwent Malone appendicostomy and Mitrofanoff in 2009; the Mitrofanoff used small bowel and was later closed.
The appendicostomy was placed in the umbilicus and did not have plication or a valve to prevent reflux.
Urology initially managed leakage with Deflux (biodegradable gel injection); when leakage recurred, plication was performed and stopped the leakage.
One year after plication, the patient lost 30 pounds and had recurrent leakage; re-plication stopped leakage but the catheter could not be replaced at 4 weeks.
IR was able to place a 5 cm channel-length AMT button into the appendicostomy.
It is important to know the type of malformation, quality of sacrum, and quality of spine to estimate likelihood of continence before committing to a Malone.
This patient is flush-dependent due to tethered cord and relies on enemas to stay clean.
Alternatives to split appendix include Monty-Mitrofanoff (small bowel conduit for bladder) or neo-Malone (cecal or right colon flap for bowel channel).
Initial management of leakage includes ensuring the patient is doing enemas effectively and is not backed up, and thickening stool with water-soluble fiber.
Poiseuille's law governs fluid flow through a tube: flow is proportional to radius to the 4th power and inversely proportional to length. A longer or narrower appendix reduces flow.
Decision rules for appendix allocation: short stumpy appendix → Malone, small-bowel Monty for bladder; 5–7 cm appendix → Mitrofanoff, neo-Malone for bowel; ≥7 cm appendix → can be split.
Minimum appendix lengths: 2 cm for Malone, 5 cm for Mitrofanoff.
For 4–7 cm appendices, one option is to give 90% to urology and lengthen the Malone stump into the cecum using non-cutting endoGIA stapler or hand-sewn non-absorbable braided suture.
Two plication wrapping techniques: Nissen-type wrap (make mesenteric window, wrap cecum 360° around appendix) vs. 180° fold-over wrap from both ends. Choice depends on mesenteric anatomy.
When doing fundoplication-style wrap, make one window at the base and placate through it to avoid crunching the mesentery.
Pay attention to ileocecal valve location when creating Malone and plication to avoid causing obstruction at the ileocecal valve.
Small bowel volvulus around the appendix is rare but has been seen in 2–3 cases.
If flushes are not working or patient has nausea, do a contrast study through the Malone to check for reflux into terminal ileum, which makes the Malone ineffective.
During plication, pass the catheter after each stitch to ensure it passes in the intended direction.
Use a 10 Fr coude catheter as a bougie during plication, then check catheter passage at the end; this usually prevents a single offending stitch from causing obstruction.
Stenosis rate can be minimized by using 10 Fr tube (not 8 Fr), leaving it in for one month, and catheterizing twice daily.
Many surgeons use an indwelling G-tube device (now available in 10 Fr) to stent the channel for many months, which reduces stenosis incidence.
Leaving an indwelling tube prevents stenosis but increases risk of leakage (valve is stented open) and prolapse (pressure on appendiceal base pushes up mucosa).
Urologists almost never get stenosis of Mitrofanoff because they catheterize every 4 hours; applying this principle (twice-daily catheterization) to Malones has reduced stenosis rate.
After two wraps, if leakage recurs, consider whether the appendix is too short and needs lengthening.
In the presented case, after second plication the exposed appendix was ~1 cm brought to umbilicus; after plication the tube could not be re-passed and imaging shows a bend in the tract at the likely obstruction point.
For a patient who wants to catheterize (not leave indwelling tube), use a Malone plug for a few months then taper the time the plug is out each day to allow the tract to mature.
To visualize a difficult Malone ostium, use Lone Star retractor with pins in the umbilicus for exposure, then identify the hole and pass a catheter.
Blind puncture of a Malone tract is risky because the appendix is thin and it is easy to enter the side wall.
To find a micro-hole in a stenosed Malone, blow up a Foley balloon to occlude the umbilicus, inject contrast under pressure, and look for any pinhole tract that fills.
Ultrasound can be used to localize the appendiceal lumen (like finding an appendix), then needle-localize under ultrasound guidance to rescue a lost Malone.
Appendicitis cannot occur in a patent Malone because there is no obstruction (pathophysiology requires obstruction).
One case: patient had appendicitis at time of planned Malone; procedure was aborted, appendicitis treated medically, and Malone performed 3 months later.
Do not remove the appendix during laparoscopic appendectomy in patients with Hirschsprung, ARM, spine issues, absent sacrum, or spina bifida because they may need it for future Malone or Mitrofanoff.
In South Africa, the appendix is never routinely removed during laparoscopy; routine appendectomy is a United States practice.
Always send the appendix tip to pathology when doing a Malone; one case identified a carcinoid (neuroendocrine tumor) on pathology.
About 60% of the time a split appendix can be successfully used for both ACE and Mitrofanoff; 40% of the time it cannot be made to work.
The most common Malone complication is stricture, occurring in 17–20% of patients.
Dr. Fisher and Dr. Levitt did 10 Malones without plication and 5 leaked; after that they placated all appendices and have not had leakage in several years.
A neo-Malone does just as well as an appendix-based Malone, but an appendix-based Mitrofanoff does much better than a small-bowel Monty.
A floppy cecum visualized laparoscopically may indicate volvulus risk; check alignment of Treitz ligament before completing the case.
Only 10–20% of patients have problems with their Malone post-procedure.
Malones are indicated for patients needing mechanical bowel-clearing assistance: continence issues unresponsive to medication, functional constipation, colonic dysmotility, ARM patients with no continence potential, and spina bifida patients who may also need Mitrofanoff.