**1. Introduction**

#### **1.1 The bladder and manifestations associated with spina bifida**

The abnormal development of the neural tube is considered the most common cause of neurogenic bladder dysfunction in children. Nearly all patients with myelomeningocele (over 90%) will have some type of bladder dysfunction (neurogenic bladder), and 30–40% of these children will develop some degree of renal disease as a long-term complication if treatment is not implemented at an early age in childhood. [1]

Depending on the severity of the fusion defect and its location, a variety of neurological deficits can be seen, with variable impact on somatic, parasympathetic and sympathetic innervation of the bladder. For unclear reasons, the level of the lesion correlates poorly with urodynamics findings and the severity of lower urinary tract dysfunction. [2] This affects its ability to store and empty urine and can lead to chronic kidney disease by poor bladder dynamics. Urological problems, including urinary tract infections, incontinence, and renal failure, are a significant cause of morbidity and mortality. Long term mortality is associated to urological complications in approximately 33% of these patients. [3]

Children with myelomeningocele also have increased risk of developing kidney stones. In one study, the prevalence of kidney stones was 4 percent among children with spinal dysraphism, compared with 0.2 percent in healthy children. Likely mechanisms for this predisposition to upper tract urolithiasis include immobility (with resultant bone resorption), bacteriuria, and urinary stasis. [4]

The bladder is a hollow muscular organ whose function is to store urine to about 400–500 mL in adults and to void as a consequence of a consequence of a filling stimulus. The micturition cycle is the continuous event of storing and voiding of urine. Normal micturition lasts approximately 15–20 seconds, and typically the bladder empties seven times a day and, usually, never at night. Under normal conditions, the bladder works at low pressures constantly. That means that during filling phase, its pressure does not exceed 10 cmH20. This condition allows the continuous gravitational flow of urine from the ureter to the bladder, and not vice versa. When, for abnormal conditions, the pressure in the bladder exceeds 40 cmH20, urine flow stops and flows back to the ureters, causing their dilatation, and in the long term alteration of kidney function, culminating in end-stage chronic kidney disease if not treated promptly. Chronic kidney disease is one of the most frequent causes of mortality in patients with spina bifida. [5]

After surgical management, walking with or without aids can be achieved in all patients with sacral levels and 95% with low lumbar lesions, while lower urinary tract (LUT) dysfunction tends to remain as large post-void residual volume, high voiding pressures, and urinary incontinence. In contrast, in patients with occult spina bifida, most cases are incidentally found during X-ray screening of low back pain. The vast majority is asymptomatic. Some cases are accompanied by lipomeningomyelocele, dermoid cyst, or thick flum terminale with minimum skin changes such as a dimple and focal hypertrichosis. In this scenario, LUT dysfunction may present in late childhood or in adulthood, and the severity of symptoms can vary, from nocturnal enuresis to urinary retention. In other words, the impact of the LUT will depend on the type of spinal dysraphism, whether it is a cystic or it is limited to an occult presentation.

The pattern of dysfunction caused by spinal dysraphism is determined by the site and type of lesion. Patterns are divided in three regions: the region above the pons, the region between the pons and the sacral cord, and the sacral cord and infrasacral region. Each region has particularities in bladder function. It is important to clarify that the manifestations according to this classification are not exact in all cases. The presentation of the neurogenic bladder in spina bifida is unpredictable. The clinical manifestations tend to present great heterogeneity. These mixed lesions can occur especially with lesions in close proximity of the conus medullaris. [6]

A detailed description of the most frequent sites affected by spina bifida are explained below:

#### **1.2 Infrapontine-suprasacral lesions**

A spinal cord lesion above the lumbosacral level, depending on completeness of the lesion, may eliminate (complete lesions) or at least reduce (incomplete lesions) voluntary cerebral control of micturition leading to neurogenic detrusor overactivity mediated by spinal reflex pathways. Detrusor overactivity has important clinical implications: reduced bladder capacity, detrusor-sphincter dyssynergia with post-void residual urine, incontinence, and a high intravesical pressure, which translates to a higher risk for chronic kidney disease. Severity of the clinical

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*Urologic Implications and Management in Spina Bifida DOI: http://dx.doi.org/10.5772/intechopen.94938*

manifestations will depend on a complete injury is present and the level of injury

*Patterns of bladder dysfunction caused by neurological disorders: (A) Suprapontine lesion pattern;* 

*(B) Infrapontine-suprasacral pattern; (C) Sacral/infrasacral lesion pattern.* 

Lesions in this site will have predominantly voiding symptoms related to a hypocontractile (if incomplete lesion is present) or acontractile detrusor (complete lesion). The clinical presentation is due to injury to the parasympathetic motor nuclei that innervates the detrusor muscle. Stress urinary incontinence is usually related to Onuf's nucleus injury and pudendal nerve dysfunction over the striated sphincter (**Figure 1**).

Lower urinary tract manifestations are divided into two groups: storage and voiding symptoms. Storage symptoms appear as an alteration in the filling phase of the micturition cycle. These symptoms include: increased voiding frequency,

Voiding symptoms appear as a difficulty during urination or prior to the onset of it. They include: difficulty to initiate urination, need to strain or effort to initiate and maintain urination, weak or intermittent urinary stream, terminal drip, dysuria

**2. Management of bladder storage and voiding symptoms**

and urgency. These symptoms result in incomplete voiding.

urgency, nocturia, urinary incontinence, and painful bladder syndrome.

(the higher, the more aggressive).

**1.3 Sacral-infrasacral lesions**

**Figure 1.**

*Urologic Implications and Management in Spina Bifida DOI: http://dx.doi.org/10.5772/intechopen.94938*

**Figure 1.**

*Patterns of bladder dysfunction caused by neurological disorders: (A) Suprapontine lesion pattern; (B) Infrapontine-suprasacral pattern; (C) Sacral/infrasacral lesion pattern.* 

manifestations will depend on a complete injury is present and the level of injury (the higher, the more aggressive).
