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Page 4 of 11 Tinoco et al. Mini-invasive Surg 2021;5:28 https://dx.doi.org/10.20517/2574-1225.2021.35

diversions [12,13] .

Urinary leakage
Ileal conduit ureteroileal anastomosis leak occurs in 2%-5.5% of the patients in the short term. Urethral
anastomotic leaks in orthotopic neobladders are more frequent, reaching a rate of 25% in the first 90 days.
In a case series by Nazmy et al. , of the RARCs with neobladder, 25.3% had urethral leaks but most were
[2]
minor and only 7.7% had a leak requiring catheterization, in line with previous reported rates. Treatment is
most frequently conservative .
[2]

Late post-operative complications
As studies in urinary diversion complications usually focus on early complications due to the high early
[14]
mortality of the underlying cancer, with cancer-specific survival rates of 66% at 5 years , high-quality
information on long-term complications is sparse. Long-term complications are most frequently related to
the urinary diversion itself than the extirpative radical cystectomy. A large series of conduit patients (1057
patients) reported a high long-term complication rate of almost 80% at 20 years but a low reintervention
[15]
rate of 6% . In their series of about 1000 patients with ileal neobladder followed over 25 years, Hautmann
et al. report a long-term complication rate of 40.8%, mostly diversion-related, with 3 neobladder-related
[16]
deaths. They underline the importance of standardized reporting of long-term complications in a time-
dependent matter, explaining that only this way investigators can stop underrepresenting late complications
since the number of patients decreases with time . However, studies with this methodology are still
[16]
lacking, so most of the following complication rates are still calculated on a non-time-dependent matter.

Renal failure
New onset of renal failure occurs in 19% at a median of 2.3 years, with 2.5% progressing to renal
replacement therapy at a median of 8.4 years . This is intimately related to ureteroenteric stenosis causing
[15]
hydronephrosis, which will be reviewed below, and also to chronic infection and reflux of infected urine. It
remains to be clarified if this loss of renal function is greater than the expected age-related deterioration.
Careful follow-up is needed.

Metabolic abnormalities
Metabolic complications are linked to the intestinal shortening, the bowel segment resected and the
absorptive properties of the conduit or neobladder intestinal mucosa. Acid-base disorders, vitamin
deficiencies and electrolyte disturbances are consistently reported in the literature. The most frequent pH
disturbance is metabolic hyperchloremic acidosis due to chloride absorption and bicarbonate excretion,
especially if a colonic segment is used. Vitamin B deficiency is also expected, as this vitamin is absorbed in
12
the terminal ileum, a segment frequently resected to use both in conduits and neobladders. This
hypovitaminosis is mainly asymptomatic but can evolve to megaloblastic anemia, neuropathy, glossitis, and
other diseases after the body’s stores are depleted, which usually last 3-5 years .
[17]
A large series of intestinal conduit diversion patients described 10.2% of metabolic acidosis requiring
alkalinizing treatment and 3% of vitamin B deficiency occurring after a median of 9 years after surgery .
[15]
12
[1]
In continent diversions, long-term metabolic abnormalities can occur in as high as 50% of the patients . In
a neobladder sample, metabolic acidosis was diagnosed in the early post-operative period but 33% of the
patients needed alkalinizing therapy for longer than 1 year and 1% of the patients were rehospitalized due to
the acid-base imbalance .
[16]