Risks and Complications
Mr Jeremy Ockrim, MD BSc (Hons) FRCS (Urol)
Honorary Lecturer University College London (UCL), Consultant Female and Reconstructive Urological Surgeon, Institute of Urology, University College London Hospital (UCLH)
Mitrofanoff formation is a complex surgery that pushes the limits of tissue tolerances and the technical expertise of surgeons. In the United Kingdom this work is only performed in expert tertiary centres and a small number of surgeons trained and performing sufficient numbers to maintain this expertise. Even in expert hands the revision rate for Mitrofanoff is high. In contemporary series the revision rate is approximately 30-60%. In 10 year of follow-up at University College Hospital the revision rate is approximately 40%, although half of these revisions are minor procedures to adjust the skin opening to the Mitrofanoff. In the other 20% of cases, major surgery is required to refashion or replace the valve mechanism. The revision rate depends upon the initial reason for Mitrofanoff diversion, the nature of the tissue damage inside, the age of the patient and the length of time from the procedure.
Perioperative bleeding, bowel obstruction or bowel leakages are the cause of early complications in the period immediately after surgery. Later complications occur with catheterization of the Mitrofanoff and the most common issues are stenosis of the conduit (scarring of the tube preventing easy passage of the catheter), leakage past the valve mechanism, and discomfort with catheterisation.
Other important considerations are urinary tract infection, bladder washouts and bladder calculi (stones). The passage of a synthetic catheter (made from either silicone or PTFE) results in permanent colonization of the bladder with bacteria. If the bacteria migrates across the bladder lining then urinary infection occurs. The rate of urinary infection depends on clean catheter technique and the ability to keep the bladder drained. Urinary infections occur in up to 20% of patients each year but can be managed by selective antibiotic use.
Patients with reconstructed bladders created from bowel experience mucus production occurring. For most patients bladder washouts using a syringe system need to be employed to prevent mucous build up. The combination of urinary stasis, mucus production and bacteria increases the risk of stones, which can occur in up to 20% of patients. The use of significant lengths of bowel to make neo-bladders can result in metabolic disturbances (imbalance of blood salts). Metabolic acidosis is a common consequence of neo-bladder reconstruction, and in some cases bicarbonate tablets are required to neutralise acid load and prevent bone demineralisation. Vitamin B12 and folate levels can also be affected and monitoring and supplementation by monthly injections and tablets may be required.
Monitoring of the kidneys usually on an annual basis by ultrasound scan is generally recommended to ensure that kidney dilatation (hydronephrosis) secondary to neo-bladder function or narrowing of the plumbing joins (anastomotic stricture) does not occur.
A Mitrofanoff tube is used to access the bladder when urethral integrity is lost. Urinary continence can be achieved in 70-100% of patients. Patients have to be aware that surgery is complex and that there is significant revision and side-effect profile. The Mitrofanoff requires long-term surveillance input from both the patient and the clinical team. In specialist centres the team will include specialist nurses who are an essential liaison for patients who have continent Mitrofanoff as well as incontinent stoma diversions. The vast majority of catheter related problems can be managed with their care. In the experience at University College Hospital London 80% of patients successfully manage Mitrofanoff continence over a long period of time (greater than 10 years), allowing for a 40-50% revision rate. There are very few patients who request change from Mitrofanoff system to a stoma bag. Although Mitrofanoff cannot be considered a cure, it offers the potential for a better quality of life and normalisation of daily activities. Over 90% of patients are able to return to work and restoration of professional and social relationships following the Mitrofanoff procedure.