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Urology & Nephrology
Neurogenic lower urinary tract dysfunction, common in patients with chronic spinal cord injury, inevitably results in urological complications. To address neurogenic lower urinary tract dysfunction after spinal cord injury, proper and adequate bladder management is important in spinal cord injury rehabilitation, with the goal and priorities of the protection of upper urinary tract function, maintaining continence, preserving lower urinary tract function, improvement of spinal cord injury (SCI) patients’ quality of life, achieving compatibility with patients’ lifestyles, and decreasing urological complications.
- spinal cord injuries
- urinary catheterization
- bladder
1. Urological Complications in Chronic SCI Patients
As summarized in Figure 1, NLUTD gradually and inevitably results in urological complications [16,17,18], which are closely related to each other. The rate of urological complications remains high in patients with chronic SCI [12,19]. Furthermore, the level of SCI and urological complications are closely associated [20,21]. As summarized in Figure 2, Chen et al. analyzed urological complications based on different SCI levels and reported that severe UI occurred significantly in patients with cervical and thoracic SCI, whereas urolithiasis was found to be more significant in patients with sacral SCI than in other levels of SCI [12]. Weld et al. analyzed bladder dysfunction based on urodynamic findings, and high rates of poor bladder compliance and high detrusor leak points were found in patients with sacral injuries [22]. However, patients with combined suprasacral and sacral injuries may have relatively unpredictable urodynamic findings and different estimated voiding dysfunction. Therefore, it is important to screen high-risk patients with SCI, especially when the detrusor leak-point pressure is higher than 40 cm H2O, indicating that the upper urinary tract is endangered [23,24].
Figure 1. Urological complications in chronic spinal cord injury patients. * Catheterization and urine stasis were mainly related to bladder stones. Abbreviations: SCI, spinal cord injury; NLUTD, neurogenic lower urinary tract dysfunction; VUR, vesicoureteral reflux; NDO, neurogenic detrusor overactivity; UTI, urinary tract infection.
A UTI is the most common reason for SCI patients presenting to the emergency department and being re-hospitalized [25]. UTIs were reported to occur in 100% of patients with SCI in one study with at least a 40-year follow-up [26]. The incidence of UTI was reported to peak in the 1st and 10th five-year intervals [26]. Pickelsimer et al. conducted a 10-year follow-up study, in which UTI, hydronephrosis, and urolithiasis were the three main complications of NLUTD [27]. However, Chen et al. compared the urological complications at different time periods after SCI and found that there was no significant difference in the occurrence rate of urological complications among different SCI durations [12]. Another retrospective study found that the percentage of patients with urolithiasis was 20% and 80% before and after 20 years after SCI, respectively [22]. Overall, most complications initially occurred during the first 25 years after SCI. Close follow-up of UTIs, renal condition, and bladder function is important for all SCI patients and at any disease duration.
2. Bladder Management of Urge Urinary Incontinence (UUI) in Chronic SCI Patients
In an assessment of 236 patients with a mean follow-up of 24 years, 43% of patients reported UUI, with paraplegics reporting daily incontinence more frequently than tetraplegics (presumably because of catheter dependence in the latter group) [48]. Only 19% of patients used some form of medication for assistance in managing their incontinence. Surprisingly, CIC was associated with higher rates of UUI than other types of bladder management. In a study by Blanes et al., which included 60 patients with traumatic paraplegia, the complication rate of UUI was found to be more than twice that found in a previous report [49]. Current evidence shows that the effects on bladder function depend on the different levels and locations of SCI [20], which may potentially explain the different rates reported by these two studies.
The appropriate management of NLUTD in patients with SCI is a major challenge for urologists. In most patients with suprasacral SCI who have neurogenic detrusor overactivity (NDO) with or without detrusor sphincter dyssynergia (DSD), bladder management by patients themselves depends on good hand dexterity, powerful abdominal muscle strength, intact bladder sensation, and coordination of the urethral sphincter during stimulation to voiding [22]. Regarding the medication for NDO, antimuscarinics are the most common treatment and are suggested as the first-line treatment by current guidelines [32]. The role of Beta-3-adrenergic receptor agonists, which are not yet approved by the FDA for the treatment of neurogenic bladder, is still unclear [50]. In a recent systemic review, mirabegron was shown to improve the storage symptoms of NLUTD and urologic QoL with very few side effects [51]. Improved maximum cystometric capacity and bladder compliance were demonstrated after treatment with mirabegron in only two studies with short follow-ups [52,53]; however, other studies showed no significant changes in the urodynamic parameters [54,55]. Vibegron, another novel Beta-3-adrenergic receptor agonist, was reported to improve bladder capacity and bladder compliance without apparent adverse effects in SCI patients with NLUTD in two recent studies with limited cases [56,57]. Further prospective studies are necessary for the role of Beta-3-adrenergic receptor agonists in the treatment of NDO.
Currently, it is possible to use a botulinum toxin A (BoNT-A) injection over the bladder detrusor to decrease detrusor contractility [58,59]; a BoNT-A injection over the urethral sphincter to decrease urethral resistance [60,61]; or combine detrusor and urethral BoNT-A injections to spontaneously improve bladder storage and emptying [62]. Although the efficacy of BoNT-A over the sphincter was reported to be high with few side effects, this treatment is not licensed and the necessity of reinjection is its main disadvantage [60,63,64]. In addition, because of limited evidence from small studies, further randomized studies are still needed to comment on the effectiveness of BoNT-A and the optimal dose [65].
3. Long-Term Complications and Satisfaction of Augmentation Enterocystoplasty (AE) in Chronic SCI Patients
Currently, the first-line treatment for NLUTD in SCI is anticholinergic agents, timely voiding schedules, and CIC in relatively good circumstances, followed by detrusor BoNT-A injections when the effects of conservative treatment are inadequate [32]. Repeat BoNT-A injections every 6–9 months are necessary to maintain the therapeutic effects of NDO, especially in patients with chronic SCI [58,96]. If the outcome is still refractory to repeated BoNT-A injections, intravesical pressure will remain high, which eventually leads to hydronephrosis, renal failure, and UUI, so more aggressive surgical treatment should be considered to obtain life-long therapeutic effects instead of periodic BoNT-A injections [71].
AE should be considered in patients with reduced bladder capacity and poor compliance due to refractory NLUTD [97,98]. This procedure is recommended for reconstructing the bladder and increasing the bladder capacity and, therefore, has been used to treat bladder dysfunction in adults and pediatric patients with myelomeningocele [99]. AE can effectively reduce intravesical pressure during bladder storage and increase bladder capacity in patients with end-stage bladder diseases or refractory detrusor overactivity [100]. Although AE is a procedure with long-term durability and high satisfaction, some major complications still exist [2]. Overall, 86.9% of 76 patients who underwent AE were well or moderately satisfied with the treatment outcomes, and the postoperative UI rate was only 16.5% in a large cohort by Wu et al. [101]. Moreover, 76% of patients required CIC, whereas others could void spontaneously with the Credé maneuver. Among the patients who needed CIC, some finally chose an indwelling transurethral catheter or cystostomy for convenient bladder emptying. In addition, AE is associated with a risk of bladder malignancy. A recent systemic review reported that the estimated incidence of developing a malignant tumor after AE ranged from 0 to 272.3 per 100,000 patients/year [102,103,104,105,106,107,108,109,110] and that 51.6% of the malignancy was adenocarcinoma. Up to 90% of bladder malignancies were diagnosed more than 10 years after AE. Although the exact mechanism of carcinogenesis after AE is still unclear, several factors, such as bacteriuria, chronic inflammation, and urinary hyperosmolality conditions, are reported to be possibly involved [111,112,113,114,115,116]. The follow-up time for regular surveillance after AE is controversial; however, an annual cystoscopy starting 10 years after AE was recommended by most studies [102,105,117,118].
AE is usually performed during the final step of NDO treatment due to the relatively high rates of postoperative complications. In a small prospective study comparing the QoL between SCI patients who underwent AE (n = 16) and those who underwent repeat BoNT-A injections (n = 14), the continence rate and QoL index were both significantly higher in the AE group (continence rate: 87.5% vs. 42.3%, p = 0.0187; QoL index: 1.625 vs. 1.077, p = 0.037). The overall outcome was good and no patients post-AE had poor bladder compliance or higher intravesical pressure at the filling phase [119].
This entry is adapted from the peer-reviewed paper 10.3390/jcm11226850
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