This is one of my pet peeves in regards to sling surgery, or any pelvic surgery. General anesthesia, spinal anesthesia, or any urological, gynecological, or pelvic surgery can and should be expected to have an effect on the bladder and one's ability to void after surgery. Though a minor surgery, sling surgery requires dissection around the urethra, and it may be difficult for some women to void afterwards. This should be expected and is not abnormal. The bladder is quite sensitive to surgery/anethesia and will recover function quite easily afterwards, but there are times when it simply is "on the fritz" and will not work. This takes forethought, time and patience to see through.
Though sling surgery is championed by many to be quick and easy, "routine", "minimally invasive", the perception that nothing can go wrong, is, wrong.
I routinely send the patient from the operating room to recovery with a catheter and guaze packing in the vagina. After the effect of anesthesia wears off about an hour or so later, I will have my recovery room nurses remove both, and then give the patient time to try to void over the next hour or so. Waking up with a catheter will give the sensation of needing to void, but it is better, in my opinion, than waking up with a full bladder and then unable to void. I have my patients void after surgery prior to leaving the hospital and will check their "residual urine" with a bladder scanner to be sure there is little leftover. This lets me know that the bladder is functional and an ER visit will be unlikely later that night.
If bladder function is known to be not so good going into surgery, I do not expect the bladder to function promptly right away, and I will therefore send the patients home with a catheter for a day or so. This may sound uncomforable, but the catheter is better than having the pain or bloat of a bladder that won't empty. Having it in overnight will also help sleep since it eliminates the need to wake up for the bathroom.
When the bladder cannot empty after surgery and goes into retention, it stretches, and this transient stretch injury needs to recover prior to normal voiding. Simply removing the catheter one day later after a retention episode is not enough time. Leaving the catheter in the bladder for 3-7 days ensures good bladder recovery and minimizes the need for further repeat catheterization. If the catheter is removed too soon after it has been stretched, the bladder will simply not work well, and patients will experience pain and small volume voids with urge and spasms. Repeated catheterizations increase infection risk.
If you are considering sling surgery or other urologic/gynecologic surgery, simply ask your urologist/gynecologist to do a bladder scan on you in recovery prior to leaving. An ounce of prevention...