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)
The causes of bladder dysfunction are diverse and dependent on age. The spread of each of these conditions that subsequently went onto Mitrofanoff diversion over the last five years at University College Hospital London is shown on Table 1.
Table 1. 130 Patients Undergoing Mitrofanoff Diversion at University College London Hospital, 2008-2013.
In the paediatric setting most patients have congenital abnormalities. In the Western world, live births with urogenital malformations are on the decrease with improved maternal health (including folic acid supplementation), antenatal screening and surveillance. The most common conditions particularly Spina Bifida (with an incidence of 1-2 of every 1000 births) are in decline. Bladder Exstrophy and Epispadias, Posterior Urethral Valves and Prune Belly Syndrome occur in less than 1 in every 50,000 births.
Trauma and Disease of the Central Nervous System:
In the young adult population bladder dysfunction can be a consequence of infections (eg meningitis) or traumatic spinal cord injury. Central nerve damage results in a failure of bladder relaxation resulting in the pressure in the bladder to be high (neurogenic bladder) and causing back-pressure on the kidneys affecting their drainage, and risking kidney failure. When this is combined with failure of the urethral sphincter (control valve) to relax, it is impossible to empty the bladder through the normal voiding route. In some young women, failure of sphincter relaxation can be a primary cause of voiding difficulty and retention. Catheterisation is required via the urethra or an alternative route.
In older populations inflammatory conditions of the bladder and the urethra can occur. Although mild inflammatory cystitis is relatively common in young women, severe inflammatory (interstitial) cystitis (inflammation of the bladder) is rare (2 per every 1000 women; female to male ratio 5-1). Bladder inflammation may also be caused by infections (eg schistomiasis, tuberculosis), chemotherapy drugs (eg cyclophosphamide) or radiotherapy. In the most severe cases bladder removal (cystectomy) is obligated. Urethral structures can be caused by infections, particularly sexual infections (chlamydia and gonorrhoea) autoimmune inflammatory conditions (particularly balanitis xerotica obliterans) or surgical trauma to the urethra.
As patients grow older there is an increased risk of cancer of the lower urinary tract. Bladder Cancer is the 7th most common cancer in the United Kingdom with over 10,000 cases diagnosed each year (male to female ratio 2.6 - 1). When the cancer involves the urethra the normal access to the bladder is lost. Bladders can also be significantly damaged by the treatment for bladder, gynaecological cancer (uterine and cervical cancer) and rectal cancer. Radiotherapy treatment for pelvic cancers can cause contraction of the bladder with neuropathic dysfunction as described above.
Urethral continence can also be lost following failed surgery for stress leakage, urovaginal fistulae (a surgical induced defect between bladder and vagina most commonly caused by hysterectomy in Western medicine and protracted childbirth in developing countries) and rarely urethral diverticulae (a rare malformation of the urethra). In the most complex of these cases it is not possible to restore normal voiding and a Mitrofanoff diversion may be considered.