Voiding difficulty and retention of urine following surgery for urinary stress incontinence is becoming less common, but is nevertheless a stressful and uncomfortable complication for both patient and surgeon. Having said that, the incidence is probably becoming less with the use of mid urethral tapes, this condition probably also remains under diagnosed and under reported.
The two major issues concerning post operative urinary retention are:
- Can it be predicted and therefore prevented
- What to do about the problem once it arises.
Causes Of Post Operative Voiding Dysfunctions
- Undiagnosed pre-existing condition.
- Factors related to anaesthesia e.g general anaesthesia, regional anaesthesia, atropine, anaesthetic reversal agents and analgesics
- Post operative pain.
- Oedema and swelling around the urethra and bladder neck.
- Operative technique e.g overelevation of the bladder neck with colpo-suspension and urethral compression with midurethral tapes.
- Other possible causes of post operative voiding dysfunction are previous incontinence surgery, age and post menopausal status.
The reported incidence of post operative voiding difficulty and retention of urine varies greatly in the literature and is frequently thought to be under reported.
Comparative studies between colpo-suspension and tension free vaginal tapes suggest that the incidence is approximately 7% in both of these procedures. The reported incidence of voiding dysfunction following mid urethral tapes, either by the retro-pubic or trans-obturator route seems to settle between 4 and 6 % but has been reported as high as 10%. Reported incidence of voiding dysfunction in previously used procedures such as Burch colposuspension, Marshall Marchetti Krantz procedures, slings and needle suspensions have varied between 5 and 22%.
Voiding dysfunction following the injection of bulking agents, does not seem to have been a major problem.
Prediction Of Post Operative Urinary Retention
- Although there is no universal agreement, it is important to pay attention to the symptoms of voiding dysfunctions listed above. • History of age, menopausal status and previous surgical history should be taken into account.
- The presence of a raised residual urine.
- Uroflowmetry of less than 15ml/ second.
- Abnormalities of urodynamic studies, particularly those suggestive of outflow obstruction and poor detrusor activity for whatever cause. • Inexperienced surgeon not following recommended techniques
- Prevention. Attention should be given to the above predisposing factors. In the care of a trained uro-gynaecologist after careful assessment, these factors do not necessarily preclude the use of surgery for the treatment of urinary stress incontinence.
- Counselling. Patients having surgery for urinary stress incontinence should all be counselled that urinary retention and voiding difficulty might be a complication in up to 10% of cases. Furthermore, in cases where voiding difficulty might be anticipated, it might be worthwhile teaching clean, intermittent self catheterisation pre-operatively.
- Temporary causes of voiding dysfunction and retention should be treated expectantly. Within a few days, swelling, bruising and oedema should disappear and various drugs contributing to the problem should be excreted. The treatment of pain and constipation are important.
Post operative voiding difficulty with high residual volumes and urinary retention might occur either in the immediate post operative period or much later, even after years. The management of the problem related to the surgical procedure itself, particularly with the use of mid urethral tape, is according to whether the diagnosis is made in the immediate post operative period or much later.
- Early post operative voiding difficulty, particularly with the presence of a mid urethral tape, which persists beyond the time when the reversible causes have disappeared, is usually treated early in the first 7-10 days before tissue ingrowth has taken place. This can be done as a simple surgical procedure with local anaesthesia. The vaginal epithelium over the tape is opened and the tape itself is pulled down 1-2 cm.
- Later diagnosis of voiding difficulty in the presence of mid urethral tapes, when tissue ingrowth has already taken place, needs to be done as a more formal surgical procedure either cutting or removing a portion of the tape underneath the urethra.
- Other forms of surgical release include transvaginal and retropubic urethrolysis.
A very nice description of the methods of releasing post surgical obstruction can be found in the Textbook of Female Urology and Uro-gynaecology, Volume 2 Chapter 68 by Huckabay and Nitti, Editors Cardozo and Staskin, Publishers Informa Healthcare, 2006.
The early and late release of mid urethral tapes is very successful in the management of voiding difficulties and interestingly, up to more than 60% of patients will remain continent despite cutting or removing the tape, however in some of these patients, overactive bladder symptoms might persist.
There is some difference of opinion as to whether when removing a tape for obstruction, one should replace it immediately with a new tape. There are some who recommend removing the tape and then doing a cough test to assess whether there is stress incontinence, before putting a new tape in. It would seem however appropriate to adopt a wait and see policy in view of the fact that so many people, particularly with late release of tapes will remain continent after the tape cutting or removal.
In the event of planning conservative management for the above problems, it is frequently necessary to perform intermittent catheterisation and pay special attention to the treatment of overactive bladder symptoms with anti cholinergics. With the easy access to changing tension and removing and cutting mid urethral tapes, conservative management with prolonged catheterisation and the use of anti cholinergics is becoming less popular.