Surgical Considerations in Neurogenic Bladder

Does the person have a neurogenic bladder?

Has there been a recent evaluation of the lower urinary tract (urodynamics and cystoscopy)?

Has there been a recent evaluation of the upper urinary tracts (renal scan and or renal ultrasound)?

Is there urinary tract colonization and/or urinary tract infection?

What is the bacterial culture and sensitivity of the urinary colonization/infection?

What is the type of bladder management and how will it affect intraoperative and postoperative management?

Risk of AD dysreflexia? (T6 and above)

What is the risk of bladder stones? (increased risk with indwelling catheter with recurrent bladder stones or catheter blockage)

Prior to a major procedure, it is often important to know the status and function of the upper and lower urinary tracts. This information may already be available for review since it is not uncommon for a person with an SCI to have a yearly urological evaluation of the upper and lower urinary tracts. Unfortunately, history, level of injury, and signs and symptoms alone are not enough to evaluate the lower urinary tracts to determine bladder function and degree of possible sphincter dyssynergia. The gold standard to evaluate the lower tract is water fill urodynamics study. Blood pressure monitoring is done in those with SCI levels at or above T6 to check for autonomic dysreflexia. Urodynamics will objectively evaluate the bladder and sphincter function. In addition it will give a good idea of the accuracy of bladder sensation of fullness. For those with SCI above T6, urodynamics is an excellent way to determine the degree of autonomic dysreflexia and whether or not a person has silent autonomic dysreflexia. Silent autonomic dysreflexia is characterized by a significant elevation in BP due to bladder distention or other noxious stimuli without having any other signs or symptoms (see section “Autonomic Dysreflexia”). Cystograms are used to evaluate for vesicoureteral reflux, and cystoscopy is used to evaluate urethral and bladder anatomy [9].

If further information is needed about the upper tracts, several tests are available depending on what information is needed. Mercaptoacetyltriglycine (MAG3) renal scans are used to evaluate renal function [10].

A Lasix renal scan can be used to help differentiate between a patulous system and extrarenal pelvis versus obstruction. Renal ultrasounds are used to evaluate anatomy. If detailed anatomy is needed, a CT scan of the abdomen and pelvis is helpful. Non-contrast studies are used to evaluate for renal and ureteral calculi. CT scans with and without contrast are also important when evaluating a person with gross hematuria or suspicion of a renal lesion found on another type of imaging study. The major drawback of CT scans is radiation exposure and the potential of an allergic reaction if a contrast agent is used.

Contrast studies are used to evaluate for other potential anatomical problems. It should be noted that serum creatinine is not a useful way to follow renal function. There has to be a 50–80 % decline in renal function before there is a change in the serum creatinine. In addition, those with SCI often have a large amount of loss of muscle mass. Since serum creatinine is dependent on muscle mass, a “normal” serum creatinine in an SCI individual may therefore indicate renal insufficiency.

Preoperatively, a urine analysis with culture and sensitivity is important. Those with neurogenic bladders, especially with indwelling catheters, are often colonized with multiple organisms, so it is important to request that the lab “culture all organisms.” Otherwise, the laboratory report result may say something to the effect “more than two organisms, probable contaminant, please repeat” or “less than 10,000 organisms probable contaminant, please repeat.” It is helpful to order a urine sample 2 weeks before an elective procedure. This allows enough time to call the lab and repeat the sample if it has been discarded due to multiple organisms. Since most individuals with SCI have bladder colonization, it is helpful to give several days of culture specific antibiotics to help reduce any inflammation in addition to providing a transient sterilization of the urine.

Types of Bladder Management and Surgical Considerations

There are several types of bladder management programs one may encounter preoperatively in those with SCI and neurogenic bladder. The most common are intermittent catheterization, indwelling suprapubic or indwelling urethral catheters, reflex voiding, and Crede/Valsalva voiding. It is important to have some familiarity with the different types of bladder management since decisions may need to be made postoperatively concerning optimum bladder management. In general it is best to keep the same bladder management postoperatively as a person had preoperatively. However, bladder function or fluid status may temporarily change postoperatively, necessitating a temporary change in bladder management. The following gives an overview of some of the more common types of bladder management. A more detailed description and the reasons for and against the different methods and potential complications can be found in the Consortium for Spinal Cord Medicine Guideline titled “Bladder management for adults with spinal cord injury” [11].

Intermittent Catheterization

Intermittent catheterization involves draining the bladder with a urethral catheter every 4–6 h. Generally a 14 or 16 French straight catheter is used. Men with enlarged prostates will often find it easier to pass a coudé (slightly curved tip) rather than a straight (tip) catheter. It is important to catheterize at a frequency to keep catheterized volumes less than 500 ml. Individuals with spinal cord injuries at or below C6 to C7 are the best candidates for intermittent catheterization because they have adequate hand function to dress and undress and can therefore be independent at performing their own catheterization.

In the hospital setting, the initial order is usually to catheterize a person’s bladder every 4 h. Special care needs to be taken not to allow a person’s bladder to become overdistended. Overdistention of the bladder is the most common cause of bladder infections due to a relative ischemia of the bladder wall and potential small tears in the bladder mucosa. The small tears can also cause hematuria when the overdistended bladder is drained and there is a return of regular blood flow to the bladder mucosa. This hematuria is usually short lived. In those with SCI at T6 and above, bladder distention is also of particular concern since it can cause potentially life-threatening autonomic dysreflexia. Autonomic dysreflexia often presents as the sudden onset of a severe headache, elevated BP, sweating, and piloerection. However, a sudden severe elevation in BP can also occur without any symptoms and is termed “silent” autonomic dysreflexia (see section “Autonomic Dysreflexia”).

Those with suprasacral injuries as discussed above usually have overactive bladders. The bladder overactivity is usually controlled with anticholinergics. Anticholinergics are very helpful at decreasing involuntary contractions and the potential for urinary incontinence and stasis of the upper tract. Therefore, it is important to resume a person’s anticholinergic medications postoperatively. It must, however, be kept in mind that anticholinergic medications will slow intestinal peristalsis and increase the likelihood of constipation. When there is a concern of constipation, it is better to give medications to treat or prevent constipation rather than withhold the anticholinergic medication. If a urodynamics study shows that the involuntary contractions are poorly controlled or a person is having significant side effects from the anticholinergics (dry mouth and constipation most common), intravesical instillations of oxybutynin (off-label) or botulinum toxin A injections into the bladder wall are usually effective at controlling the overactivity. Currently the only FDA-approved botulinum toxin to use for neurogenic and non-neurogenic overactive bladders is onabotulinum toxin A (Botox ®).

Indwelling Catheterization (Urethral and Suprapubic Catheterization)

Suprapubic and indwelling urethral catheters are most commonly used in those with suprasacral spinal cord injuries and poor hand function who are unable to catheterize themselves or do not have a willing caregiver who can perform the catheterization. Catheters are also particularly useful in a surgical setting if the person is on a large amount of IV fluid or there is a need to monitor fluid output. As discussed previously, those with suprasacral SCI usually have overactive bladders. They are usually on maintenance anticholinergic medication to quiet their bladder just like those with suprasacral SCI on intermittent catheterization. The above discussion regarding those with overactive bladders and use of anticholinergic medications applies to those with indwelling catheters. In fact, it is even more important to make sure that those with indwelling catheters are on anticholinergic medications since the indwelling catheter will often trigger involuntary bladder contractions.

Currently there is a strong push to maintain a closed system and remove the indwelling catheter as soon as possible because of the increased risk of a catheter-associated urinary tract infection (CAUTI) (see section “Urinary Tract Infection”). This is not an issue with a SP (suprapublic) catheter.

Reflex Voiding

Reflex voiding is primarily used for men with suprasacral SCI who have overactive bladders and who are not able to control their urinary stream. It involves wearing an external condom catheter and a leg bag so that when the bladder has an involuntary contraction and voiding occurs, the urine flows out the bladder and urethra into an external condom catheter that is connected to tubing and a leg bag. This can be switched to a larger bag at night. There is usually some degree of sphincter dyssynergia. Generally, some type of treatment to relax the sphincter is needed to prevent back pressure to the kidneys and autonomic dysreflexia and help improve emptying of the bladder with a bladder contraction. Treatment usually involves giving an alpha-blocker. However, Botox injection into the sphincter (off-label) is sometimes used. In the past, sphincterotomy was frequently used. It is currently not used very often due to its irreversibility, frequent need to be redone, and less experience among urologists at how to perform a sphincterotomy.

Reflex voiding has limited utility in women because there is not an effective external collecting device that a woman can use. An alternative that can be used by men and women is to wear pads or diapers. Most do not like the discomfort of wearing wet pads, inconvenience of changing the pads frequently, and the expense of purchasing the pads, not covered by a number of insurance plans.

The advantages of reflex voiding are no fluid restrictions and not having to undress to catheterize the bladder. The disadvantages are having to wear and change the external condom catheter daily, the potential for skin breakdowns from the condom, and the very embarrassing situation of the external condom catheter coming off and then voiding. This is most likely to happen if the condom twists on itself before voiding and then a person voids, pushing the condom catheter off.

Crede/Valsalva Voiding

Credé/Valsalva voiding is used by those with sacral SCI who have no bladder contractions. It involves the use of intra-abdominal pressure to force the urine out of the bladder. The difference between Credé and Valsalva voiding is that those who use Credé voiding make a fist and push it into their lower abdomen over their bladder to empty their bladder. Valsalva voiding involves taking a deep breath and bearing down to push out the urine, much like trying to have a bowel movement. This method is not recommended for those with sphincter dyssynergia since high pressures are needed within the bladder to push the urine out of the bladder. There is concern that constant frequent bearing down may cause hemorrhoids and hernia or may cause or exacerbate bladder/vaginal prolapse. In general, a person needs to be sitting up in order to have enough intra-abdominal pressure to effectively “bear down” to void. An alpha-blocker is sometimes used to help quiet the sphincter and improve voiding in those who use intra-abdominal pressure to void.

Common Urological Problems Following SCI

In addition to a neurogenic bladder, there are several other urological problems encountered pre- and postoperatively in a person with an SCI (see Table 25.2). The most common potential problems are urinary tract infections and the risk of autonomic dysreflexia in those with SCI at or above T6. The following sections will discuss these problems and their management.

Table 25.2

Common urological problems in those with neurogenic bladder

Voiding dysfunction (urinary retention, urinary incontinence, or both), urinary tract infection

Autonomic dysreflexia (T6 and above)

Bladder stones and catheter blockage (especially with an indwelling catheter)

Urinary Tract Infections

Bacteria in the urine are common and an important consideration in those with neurogenic bladders. There is a lot of confusion between asymptomatic bacteriuria, which is usually colonization, and a true symptomatic infection. There are often a lot of questions with regard to diagnosis and when to treat and not to treat. The diagnosis of a UTI (urinary tract infection) in those with neurogenic bladder should not be made based solely on the presence of increased bacteria in the urine. There is consensus that three criteria must be met for an individual to be considered as having a UTI: (1) significant bacteriuria, (2) pyuria (increased white blood cells in the urine), and (3) signs and symptoms [12].

Criteria for significant bacteriuria (the number of bacteria that signify that the bacteria are truly from the bladder and not just a contaminant) depend on the method of bladder management being used: