This article reviews neurogenic bladder related to traumatic injury as well as vascular lesion of brain/spinal cord. Because urological manifestations of traumatic or vascular brain/spinal cord injury are highly diversified and complex, the approaches to achieve accurate diagnosis and administer proper treatment can be complicated. The goal of primary treatment is preservation of renal function and attainment of social continence. Maintaining low intravesical pressure and adequate bladder emptying are central to the treatment strategy. Diagnosis and appropriate urological management of these disease entities should depend on urodynamic studies because of poor correlation between clinical symptoms or somatic neurologic signs and urodynamic findings.
The mortality of patients with neurogenic bladder (NB) secondary to major neurologic abnormalities has declined dramatically with improved care for NB. However, clinical studies on this condition are still relatively lacking. This article reviews NB related to traumatic injury as well as vascular lesion of spinal cord/brain.
Mechanical/traumatic injuries to the spinal cord and brain
Although no accurate data on the overall incidence of spinal cord injury (SCI) have been obtained in the United States since 1970s, a prevalence of more than 200,000 patients with traumatic SCI has been estimated in the United States, with an incidence of approximately 12,000 patients being newly diagnosed with SCI every year. The main causes of SCI are motor vehicle accidents (42.1%) and falls (26.7%). On the other hand, more than 2 million individuals in the United States were admitted to the emergency room due to traumatic brain injury (TBI), and about 50% of the patients suffered moderate to severe injuries. The predominant cause of TBI is fall. The possibility of concurrent SCI and TBI should always be considered when encountering a patient with SCI : 11% of patients with SCI have an associated head injury. TBI and SCI may result in different types of voiding dysfunction, and their coexistence can make accurate diagnosis challenging.
Expected Bladder Dysfunction by SCI Level
In principle, SCI above the S1 level does not interrupt the integrity of parasympathetic (S2 through S4) and somatic nerves (S1 through S4). Only cortical inhibition of voiding reflex and detrusor-sphincter coordination regulated by the pontine micturition center are disturbed. Injury at the S2-S4 level can result in impairment of detrusor contractility and malfunction of pudendal nerves, which innervate the distal sphincter. Involuntary detrusor contraction (IDC) after an injury at the C2-S1 region and open fixed tone of the distal sphincter by denervation after S2-S4 injury can induce storage failure. In addition, detrusor-sphincter dyssynergia (DSD) after C2-S1 injury and detrusor underactivity (DU)/detrusor acontractility (DA) or nonrelaxing urethral sphincter obstruction after S2-S4 injury can result in failure to empty. Because the nuclei of the pelvic nerves involved in contraction of the detrusor muscle and the pudendal nerves responsible for contraction of the striated sphincter are located in different portions of the sacral cord (intermediolateral cell column vs ventral gray matter), sacral SCI can induce DA, leaving striated sphincter function intact.
Many studies have investigated whether urodynamic findings differ according to the level or the completeness of injuries. Table 1 shows the results of a meta-analysis of 4 relevant studies on the injury level. In summary, classification of SCI based on the level of injury gives some information, but the information seems to be insufficient for a detailed diagnosis of lower urinary tract dysfunction. Therefore, it is generally agreed that urodynamic study should be conducted to provide a precise diagnosis for each patient. In addition, little correlation between the completeness of injuries and specific urodynamic findings has been reported ( Table 2 ). The mismatch between somatic neurologic signs and urodynamic findings can be explained by the degeneration or reorganization of the neural pathway, incomplete lesions, combined lesions or extension of injuries with cord fibrosis, or an aberrant healing process. The level and completeness of the injury or the existence of vascular extension usually diversifies the types of bladder dysfunction in patients with SCI. Vascular involvement makes ischemic injury extend above and below the actual level of injury.
| Level of Injury | P Value a | ||||
|---|---|---|---|---|---|
| Cervical | Thoracic | Lumbar | Sacral | ||
| Number of Patients | 259 | 215 | 137 | 46 | |
| DO | 65% | 78% | 49% | 22% | <.001 |
| DSD | 63% | 72% | 33% | 13% | <.001 |
| DA | 9% | 9% | 39% | 70% | <.001 |
| Normal | 1% | 2% | 2% | 9% | .002 |
| References | Rapidi et al 12 (n = 154) a | Weld and Dmochowski 9 (n = 196) b | ||||
|---|---|---|---|---|---|---|
| Complete (ASIA A) | Incomplete (ASIA B) | P Value | Complete (ASIA A) | Incomplete (ASIA B-D) | P Value | |
| DSD/DO | 93% | 93% | .649 | 100% | 93% | .282 |
| DA/DU | 7% | 7% | 0% | 3.7% | ||
a Patients with cervical and thoracic lesions.
b The percentage is recalculated within the patients with C-L lesions. The percentage does not equal 100% because some patients with incomplete lesions manifest normal urodynamic findings.
Only a few reports have been published on TBI, especially on the correlation of urodynamic findings, because injured patients commonly have behavioral, cognitive, or communication problems. The injury to the brain itself, impairment of cognitive and behavioral function, or an associated SCI after TBI may induce voiding problems, such as incontinence. The most commonly expected urodynamic abnormality after TBI is IDC, which can be induced by the loss of cortical inhibition caused by suprapontine lesions. Coordinated relaxation of the distal sphincter during detrusor contraction is usually maintained. Asymptomatic urodynamic abnormalities were common in patients who sustained moderate or severe TBI, and injuries of the frontal lobes were the most common in patients with urodynamic abnormalities. In a high proportion of patients, frontal lobe injury could have contributed to detrusor overactivity (DO) and high incidence of urinary incontinence.
The incidence of urinary retention after TBI is lower than that after cerebrovascular accident (CVA). Chua and colleagues demonstrated an 8.3% retention rate after TBI, when patients were initially admitted to the rehabilitation unit, which was lower than that after CVA. The lower retention rate after TBI was likely because of the tendency toward bilateral hemispheric or subcortical involvement, which was known to be associated with IDC causing urinary incontinence or overactive bladder.
Time Frame for Symptom Presentation
Bladder management in patients with SCI should vary according to time-dependent changes that occur after SCI. Within minutes of an injury, swelling of the spinal cord occurs in the spinal canal at the region of injury, which induces ischemic injury to the spinal cord tissue. In addition, bleeding may occur in the central gray matter and possibly spread to the other parts of the cord. This event causes spinal shock. Immediately after SCI, spinal shock can occur because of the absence of function below the level of cord injury. The neurophysiology of spinal shock and its recovery mechanism remain largely unknown.
Spinal shock may last from 6 to 12 weeks after complete suprasacral SCI, which can be extended to 1 or 2 years. The duration of spinal shock in patients with incomplete SCI is shorter, sometimes lasting for several days. Competent bladder neck and DA occur in the phase of spinal shock. An electric activity can be found in the distal sphincter on electromyography. Urinary retention is therefore common, and urinary incontinence does not usually occur unless overflow incontinence exists.
As spinal shock proceeds to the recovery stage, recovery of detrusor activity is usually heralded by the recovery of skeletal muscle reflex. Therefore, the return of bulbocavernous reflex signifies recovery from spinal shock. Since that time, symptoms secondary to storage difficulties start to occur between intermittent catheterization (IC). Suprasacral SCI usually causes incontinence because of IDC. As the magnitude of IDC becomes larger, postvoid residual (PVR) becomes smaller. However, the coexistence of DO with DSD results in higher voiding detrusor pressure and PVR. With sacral SCI, urinary retention may develop because of DU or DA combined with a competent distal sphincter. It should be noted that even though patients do not have severe injuries, one-third of patients with SCI need change in urological management in the absence of neurologic change. Furthermore, more than two-thirds of patients required in urological management experienced silent deterioration of bladder function on urodynamics during long-term follow-up. This result emphasized the importance of regular urodynamic follow-up.
It was reported that long-term changes of bladder symptoms after TBI showed a time-dependent reduction in urinary incontinence. In the acute phase, 62% of patients showed incontinence and only 9.5% of them showed a high PVR of more than 100 mL. At the time of discharge, 36.9% of them had an episode of urinary incontinence, and only 18% remained incontinent at the 6-month follow-up. A recent study also demonstrated that incontinence was the predominant symptom when the patients were admitted and that bladder impairment score improved over time.
Treatment Goals and Strategies
Detailed treatment strategies should be individualized to the type of voiding dysfunction, level of injury, extent of disability, and level of care available to the patient. However, the ultimate goals of treatment in the bladder management after SCI are to preserve upper tract function with low intravesical pressure through adequate bladder drainage and to maintain urinary continence. There is no disagreement on these treatment goals among practicing urologists, although there is a lack of consensus or a standard guideline on the evaluation and management of the urinary tract.
The clinical practice guideline of the Consortium for Spinal Cord Medicine reviewed various emptying or storage methods and analyzed the merits and demerits of each method when applied over long-term. This guideline commented that IC is safe and effective and that other methods may also have their own merits if applied adequately. Proposed guideline from Abrams and colleagues emphasized that early clean IC (CIC) allowed easier bladder management, and patients with reflex voiding should be closely monitored on their bladder-emptying efficacy. In addition, the investigators emphasized avoidance of straining/Crede voiding.
Baseline investigation is generally performed 3 to 6 months after the initial injury, by which time spinal shock would have resolved. Baseline investigation consists of (1) general and neurologic history taking, (2) information gathering on symptoms, (3) performing neurologic examinations such as testing sacral reflexes, sacral sensation, and anal tone, (4) urinalysis, estimating serum creatinine levels, upper tract imaging, and (5) urodynamics. Nuclear renogram, voiding cystourethrography, cystoscopy, or computed tomographic scan may be needed during long-term follow-up. When neurologic deficit is mild in patients with incomplete SCI, physicians sometimes omit urodynamic studies in the outpatient department. However, it is noteworthy to remember that up to half of patients with mild, incomplete injuries could develop bladder dysfunction at a later date. Therefore, urodynamic studies remain valuable in the long-term follow-up of the patients with mild neurologic deficit.
Most urological centers prefer annual monitoring of upper and lower urinary tract function of patients with SCI. More-frequent follow-up is needed in the event of change in voiding pattern; development of vesicoureteral reflux (VUR), urinary tract infection (UTI), or urinary stone; change of medication; or in the presence of DSD with sustained high intravesical pressure or low compliance. Regular follow-up urodynamic studies is important to assess changes in bladder dysfunction because physiologic changes may occur even though there may be no change in overall symptoms.
Treatment goals and strategies for NB related to TBI are not much different from those of NB related to CVA. In patients with TBI, the probability of recovery from incontinence is high, whereas the occurrence of DSD or low compliance, the risk factor for upper urinary tract damage, is less common.
Outcomes
Bladder emptying
The most important issue in the treatment strategy of patients with SCI is the method applied to achieve bladder emptying. IC is the most highly recommended bladder-emptying method, except in special circumstances such as inability of patients or caregiver to perform catheterization, abnormal urethral anatomy, bladder capacity less than 200 mL, and the tendency to develop autonomic dysreflexia (AD) with bladder filling. Weld and Dmochowski recommended CIC as the safest method of bladder emptying in patients with SCI in terms of urological complications such as infections, calculi, renal scarring, and VUR. Table 3 compares long-term complications between IC and chronic indwelling catheterization from selected studies. However, change in bladder management modality over time, especially bladder-emptying method, is common in patients with SCI with NB. Significant numbers of patients abandon their initial emptying methods because of inconvenience after hospital discharge.
| Investigators | F/U (y) | Complication | IC | Chronic Indwelling Catheter | P Value |
|---|---|---|---|---|---|
| Weld and Dmochoski 24 | 18 | n = 92 | n = 150 | ||
| Weld et al 25 | Patients with complications | 27% | 51% | <.01 | |
| Decreased bladder compliance | 26% | 77% | <.01 | ||
| Larsen et al 26 | 12 | n = 86 a | n = 56 | ||
| Renal-related | 6 cases b | 20 cases b | <.01 | ||
| Urinary tract infection | 46 cases b | 48 cases b | <.01 | ||
| Stones | 16 cases b | 52 cases b | <.01 | ||
| Urethra-related | 20 cases b | 30 cases b | <.01 |
a CIC, spontaneous voiding, and external striated sphincterotomy.
Studies suggest that the CIC method significantly improved the quality of life (QoL) in patients with SCI. However, the QoL of patients with SCI was relatively reduced when compared with that of the general population. This observation emphasized the importance of ongoing training to properly implement CIC and the need for psychological support in patients who rely on long-term CIC.
Reflex voiding may be used if an external containment system, such as a condom catheter, can be maintained in place. In general, when patients with SCI use triggered voiding, close urological surveillance is required because of possible coexistence of DSD. Reflex voiding is not recommended in patients with AD, high-pressure voiding, incomplete emptying, and in female patients. Valsalva or Crede voiding may be considered when bladder outlet resistance is lowered and detrusor contraction is decreased simultaneously by sacral micturition center or sacral nerve root injuries. However, these methods should not be used in patients with DSD, VUR, and bladder outlet obstruction and are not recommended in recent publications.
Long-term indwelling catheterization is commonly used for females and individuals with high-level complete tetraplegia. Shekelle and colleagues reviewed 22 studies and found that CIC induced fewer UTI occurrences than the chronic indwelling catheter did. Moreover, bladder compliance is generally lower in patients using indwelling catheters than in those using other methods (see Table 3 ). This difference is probably because of vesical wall fibrosis induced by inflammation and infection related to chronic indwelling catheterization. For these reasons, some physicians recommend avoid long-term use of indwelling catheters, whenever possible. Additional complications related to indwelling urinary catheters are also listed in Table 3 .
Special attention should be given to indwelling catheters and risk of bladder cancer for neurogenic bladder patients. The incidence of bladder cancer in patients with SCI is known to be 2% to 10%. A recent analysis conducted by Groah and colleagues on patients who used indwelling catheters for more than 12 years demonstrated that the incidence of bladder cancer is 25 times higher in patients with SCI than in the general population. However, even though the incidence of bladder cancer is higher in patients with SCI, the absolute number of individuals who develop malignancies is actually low.
However, recent publications have challenged these views and suprapubic cystostomy (SPC), has been recently reported to be a safe management option for carefully selected patients if appropriate surveillance can be implemented. Feifer and Corcos reviewed 56 articles on SPC and reported that patients managed with anticholinergics, frequent urinary catheter changes and bladder washing, or volume maintenance procedures demonstrated similar morbidity to CIC. Therefore, more studies are needed on the complications of chronic indwelling of suprapubic catheters.
Striated sphincterotomy
The treatment aims of performing striated sphincterotomy are to preserve renal function, prevent sepsis, and ameliorate DSD and AD. A larger series of sphincterotomy showed that significant number of patients required second operations. Recurrent UTI, DSD, and upper tract dilatation were also present in two-thirds of the patients. The failures have been attributed to inadequate surgical skill, urethral strictures, and decreased detrusor contractility. In addition, reasonable alternative options for refractory DSD have become available in recent years. Therefore, patients are advised to consider the efficacy and complications of different procedures before choosing an appropriate modality.
Urethral stent
Hamid and colleagues investigated the long-term efficacy of urethral stent in 12 patients with DSD. Significant improvement of urodynamic parameters was found, and 7 patients continued to rely on urethral stents for more than 12 years. However, a recent study on second-generation thermoexpandable stents showed a different picture: the overall mean working life of a stent was merely 21 months. Nowadays, urethral stents seem to be used only in some centers because of relatively short durability, potential complications, and difficult stent explantation for eroded or obstructing devices.
Botulinum toxin
Botulinum toxin (BTX) injection can be used for detrusor overactivity (DO) and for reducing urethral outlet resistance. BTX injection is a less-invasive alternative to sphincterotomy. BTX is effective in reducing the amount of PVR, improving maximal detrusor pressure during voiding, and managing DSD.
BTX is also effective in treating refractory neurogenic DO; however, it may have less of a therapeutic effect on patients with fibrotic changes in the bladder. Most clinical studies involving BTX injections demonstrated significant improvement in clinical and urodynamic parameters without notable adverse events. Recently, the efficacy of repeated injections over a long period has been reported. Although treatment with BTX has emerged as an alternative option for managing DSD and DO in recent decades, a standardized dose and an injection protocol remain to be established.
Future Developments
Sacral anterior root stimulation
Sacral posterior root rhizotomy and sacral anterior root stimulation (SARS) can be performed to manage refractory IDC and AD. Electric stimulation of the sacral efferent parasympathetic nerves (S2 through S4) after dorsal rhizotomy induces bladder contraction. The result of a 7-year follow-up in 42 patients with SCI demonstrated reduced infection rate in 68% of the cohort; 54% achieved continence and 54% experienced improved social life. Kutzenberger and colleagues reported that 83% of patients achieved continence and most patients experienced resolution of AD. SARS has been performed for more than 30 years in a few centers and has known to be effective for micturition. However, the disadvantages of the combined rhizotomy should also be considered because of its irreversible nature.
Reinnervation of bladder by crossover nerve surgery
In 1989, Xiao and colleagues suggested the feasibility of the artificial skin-central nervous system-bladder reflex pathway below the spinal cord lesion. The assumption was that the motor axons of somatic reflex arc may regenerate into autonomic preganglionic nerves, thereby reinnervating the bladder parasympathetic ganglion cells and transferring somatic reflex activity to the detrusor muscle. From 1995 to 2003, the investigators performed L5 and S2/S3 ventral root microanastomoses in 15 patients with complete suprasacral SCI and found that 67% of individuals regained satisfactory bladder control during a 3-year follow-up. Urodynamic study confirmed a change from DO with DSD and high detrusor pressure to nearly normal storage and synergic voiding without DSD. In addition, Xiao reported that 88% of 92 patients with SCI with neurogenic DO or DA could regain bladder control 1 year after the operation. Lin and colleagues reported another promising result: 75% of subjects regained satisfactory bladder control after a similar procedure in the S1 through S2/S3 region. Although this novel procedure seems promising, further studies are required to confirm the validity of its reported efficacy. Issues on tissue engineering and sacral neuromodulation are discussed in articles by Stanasel and colleagues; and Burks and colleagues elsewhere in this issue for further exploration of this topic.
Related posts:
Urodynamics of the Neurogenic Bladder
Management Goals for the Spina Bifida Neurogenic Bladder: A Review from Infancy to Adulthood
Review of Neurologic Diseases for the Urologist
The Neurogenic Bladder and Incontinent Urinary Diversion
Botulinum Toxin Therapy for Neurogenic Detrusor Overactivity
Urologic Complications of the Neurogenic Bladder
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
