Spinal Dysraphism: A Neurosurgical Review for the Urologist |
| |
| Authors: | José Murillo B Netto André N Bastos André A Figueiredo Luis M Pérez |
| |
| Abstract: | Spinal neural tube defects are congenital malformations of the spine and spinal cord (eg, myelomeningocele) and are frequently seen in pediatric urology practice. These neurologic problems have many consequences in a child’s life and affect different parts of the body, such as the brain, spinal cord, limbs, bladder, and bowels. Because of the complexity and neurologic aspects of spinal dysraphism, many related terms and aspects of the disease are unfamiliar to the urologist. This review addresses some of the most commonly used neurosurgical terms and concepts related to spinal dysraphism.Key words: Spina bifida, Spinal dysraphism, MyelomeningoceleSpinal neural tube defects are congenital malformations of the spine and spinal cord secondary to abnormal neural tube closure that occur between the third and fourth weeks of gestation. The term spinal dysraphism includes the overall group of defects derived from the maldevelopment of the ectodermal, mesodermal, and neuroectodermal tissues, and its sequelae may affect brain, bones, extremities, and bowel and bladder functions.The incidence of spinal dysraphism ranges from 3.2 to 4.6 per 10,000 births in North America1,2; no geographic variation has been seen, and there is a relatively uniform incidence in all ethnic groups.3 There is strong evidence that there has been a decline in incidence worldwide since the 1970s1,4; however, it is unclear whether this is a transient or permanent trend. This decline is probably due to a systematic use of dietary folic acid before and during the gestational months,5 and more recently to the advent of prenatal diagnosis, which leads to therapeutic abortion in as many as half of the diagnosed cases in some countries.6 The disorder occurs equally or somewhat more commonly in female newborns (female, 1.0–1.7/male, 1.0), depending on the populations studied. Embryologically, open spinal dysraphism (myelomeningocele) is thought to occur 3 to 4 weeks after conception at the time that the neural tube is closing.7Myelomeningoceles are by far the most common spinal dysraphic condition affecting the lower urinary tract and therefore the most familiar to urologists.8 The lumbar and sacral regions are the most common vertebral levels affected9 ( | Open in a separate windowData from Bauer SB et al.9Before advances in ventricular shunting devices, the survival of a child with open spinal dysraphism was dismal, and, therefore, urologic intervention was rarely necessary. As the life expectancy of these children increased, so did the morbidity and mortality secondary to urologic complications, such as pyelonephritis, hydronephrosis, and renal failure.10,11 The need for appropriate urologic evaluation and effective management became mandatory to improve the health, longevity, and quality of life of patients.The evaluation and management of the neurogenic lower urinary tract secondary to spinal dysraphism has undergone a major evolution over the past 30 years.12–19 This has been fueled by advances in urodynamic technology and an improved understanding of the long-term effects of a urodynamically hostile bladder and bladder outlet.20–22 At the same time, improved methods for maintaining a low-pressure bladder reservoir and providing for adequate emptying through intermittent catheterization has resulted in a marked improvement in prognosis.23–34In addition to the urologic problems, patients with spinal dysraphism often have other systemic disorders that require medical attention by a multidisciplinary approach. We focus this article on the premise that a sound understanding of the neurologic aspects of spinal dysraphism will lead to enhanced outcomes for affected children. We discuss neurologic terminology, epidemiology, etiologic risk factors, associated congenital anomalies, prognosis, and appropriate neurosurgical evaluation and management. The urologic evaluation and management of the spinal dysraphic bladder will not be discussed and has previously been extensively reviewed. |
