Spinal dysraphism in children: An overview and an approach to prevent complications

SPINAL DYSRAPHISM IN CHILDREN: AN OVERVIEW AND AN APPROACH TO PREVENT COMPLICATIONS RONALD S. SUTHERLAND, LAURENCE S. BASKIN,

M.D., ROBERT A. MEVORACH, M.D., M.D., AND BARRY A. KOGAN, M.D.

pinal dysraphism, which comprises a group of congenital and acquired abnormalities of the spinal cord (Table I), is the most common primary cause of neurogenic bladder dysfunction in children, affecting approximately 1 in 1000 in the United States.’ Although the incidence appears to be decreasing, the urologic complications pose no less a threat to those affected2J; indeed, lower urinary tract dysfunction occurs in an estimated 95% of these infants.4,5 Early recognition of neurovesical abnormalities enables prompt intervention and usually prevents significant sequelae, such as damage to the upper urinary tract or, in the case of tethered spinal cord, permanent neurologic impairment. Our goals in the care of children with spinal dysraphism are: (1) to preserve renal function; (2) to achieve urinary and fecal continence; and (3) to enable these patients to develop a sense of autonomy and better self-esteem. To meet these goals, we have adopted an approach that relies on early diagnostic evaluation and frequent noninvasive monitoring to establish the basis for intervention.

S

EMBRYOLOGY

Spinal dysraphism arises from a defect in the formation of the neural tube. Present by the third week of gestation, the neural tube develops as a result of medial migration of the ectodermal neural folds. Interruption of this migration early in gestation can be either extensive or focal: when it is extensive, the infant develops either anencephaly or rachischisis, both of which are incompatible with life; when focal, the more common lesions such as spina bifida result. In normal spinal cord development, by the end of the fourth week, the vertebral bodies are formed from lateral mesodermal somites adjacent to the neural tube. If the neural tube fails to form, medial migration of the somites is blocked, thus interrupting the posteFrom the Department of Urology, University of California School ofMedicine, San Francisco, Calijornia Laurence S. Baskin, M.D., Department of Urology, U-575, University of Cdifornia, San Francisco, CA 94143-0738 Submitted:January 13, 1995, accepted [with revisions): April 14, I995 294

rior fusion of the vertebral arches. This gives rise to the malformation seen in spinal dysraphism.6 ETIOLOGY

The origin of these lesions appears to be multifactorial. Various teratogens (such as alcohol and zinc) and some medications (such as valproic acid) have been implicated. Maternal infection early in pregnancy has also been proposed, as well as exposure to heat in the form of hot tubs, saunas, and febrile illness.‘-i0 Most recently, evidence has suggested that deficient maternal intake of folic acid is associated with development of spina bifida. Supplementation may reduce the chances of acquiring such birth defects sevenfold. The pathogenesis of this has not clearly been elucidated.11J2 With regard to the regional differences noted in a large collective European study, a higher incidence of spina bifida was reported in Ireland and in the United Kingdom. l3 Although classically not a neural tube defect, sacral agenesis is often included as a spinal dysraphism; to this end, gestational diabetes has been identified as a clear cause of this disorder, resulting in sacral agenesis in 1%.14 Although no specific inheritance pattern has been demonstrated, parents with one child with spina bifida have a 4% risk of having another affected child. If two offspring are affected, the risk rises to 12%.15 PRENATAL

ASSESSMENT

Early diagnosis in open spina bifida or anencephaly may be made through screening of maternal serum for alpha-fetoprotein (AFP). Although the test is quite sensitive if results are markedly elevated, it lacks specificity: as few as 7% of mothers with repeated abnormal values actually have a child with a neural tube defect. This is especially true for samples obtained later in gestation. l6 However, an elevation in AFP of more than 3 standard deviations from the norm before 24 weeks’ gestation indicates a fetus with a neural tube defect in 70% of cases.2 Sonography has greatly enhanced the ability to diagnose spinal dysraphism in utero. Although absolute diagnosis depends on visualization of the defect (Fig. l), other suggestive findings include polyhydramnios, foot or limb deformity and UFCOLOGY~46 (3), 1995

TABLE Cystic (posterior protrusion Myelomeningocele Meningocele Lipomeningocele Myeloschisis Rachischisis

I.

Spinal

dysraphism:

types and definitions

of spinal elements through spinal defect) Cyst contains meninges, spinal cord, or nerve roots, and cerebrospinal Cyst contains meninges and CSF Cyst contains meninges, CSF, and fat Extensive open neural plate or cleft spinal cord Complete cleft of vertebral bodies and cord

fluid (CSF)

Noncystic (no protrusion of spinal elements; presence of hair tuft, sinus or dimple, discoloration or lipoma the only sign] lntradural lipoma Fatty infiltration of the spinal cord Diastematomyelia Bony spicule or fibrous band splitting the cord Dermoid and epidermoid cyst/sinus lnvagination of surface epidermis Cauda equina tumor Cord compression Anterior sacral meningocele Anterior herniation of spinal elements into pelvis Tethered cord Primary Broad, thickened cord preventing upward migration Secondary Fixation or compression of cord from postoperative adhesions, fibrous bands, lipoma, and cysts Syringomyelia Cystic degeneration of cord

ventriculomegaly. I7 When used as an initial screening for open spinal dysraphism alone, without associated serum AFP sonography fails to detect the defect in more than 63% of cases.18 However, fetal sonography in combination with serial elevations of maternal serum AFP has been found diagnostically useful, with a sensitivity of 80% and specificity of 99% for open spina bifida.19 Prenatal diagnosis permits timely parental counseling. In theory, this education should help avoid

FIGURE 1. Antenatal

the shock of finding such a defect at birth. In practice, however, we are seeing fewer neonates with spina bifida, which may be the result of elective pregnancy terminations. A significant advantage of early diagnosis is the opportunity to plan for delivery in a center with the requisite expertise to determine the appropriate manner of delivery and postnatal care. The method of delivery is highly controversial. In some instances vaginal delivery may be safezo,“; however, Luthy and associatesZ2 strongly suggest that delivery via cesarean section before the onset of labor results in a lower rate of paralysis at 2 years of age than will vaginal delivery or cesarean section after labor has begun. After the delivery, it is

ultrasound of the spine, sagittal plane. (A) The normal spine at 25 weeks’ Composite views at 30 weeks’ gestation in a fetus with marked lumbar kyphosis and a protruding Neural elements consistent with myelomeningocele are present.

UROLOGY"46 (31,1995

gestation. (B) sac (arrow).

295

ten necessary before urodynamic study Many develop urinary retention requiring some method of bladder emptying, whether by Crede or intermittent catheterization. Because Crede is not physiologic, may cause markedly increased pressures, and is inappropriate for the long term, we prefer intermittent catheterization. We have had no technical problems with catheterizing infants; furthermore, it sets the stage for future urologic care. CARE OF THE NEWBORN EVALUATION

FIGURE 2. left buttock.

Sacral

dimple

and lipoma

distorting

the

important to have a well-trained support staff consisting of, but not limited to, a neurosurgeon, pediatric urologist, neonatologist, experienced nurses, and social services personnel. NEUROSURGICAL EVALUATION AND TREATMENT Although open spinal dysraphism is the most common variant observed, closed spinal defects such as lipomeningocele or tethered cord also occur frequently 14,23-25In these cases, outward manifestations may not always be readily apparent; therefore, it is imperative that all neonates undergo a thorough physical examination. Suggestive regional signs of a closed underlying spinal dysraphic state include a sacral “pit” or dimple (Fig. 2), a hairy patch, hemangiomas, aberrant gluteal cleft, or lipoma. 26 Laxity of anal sphincteric tone may also be an early sign. The presence of other anomalies such as imperforate anus, which may have associated occult spinal cord pathologic conditions, and lower extremity deformities should alert the urologist.27 For open defects, neurosurgical intervention is performed as soon as possible as an emergency procedure. Ideally, abdominal ultrasound and a urodynamic evaluation should be performed before closure of the back defect, but in our experience this is generally not feasible. Because many of these infants experience “spinal shock” after closure, urologic intervention is of296

To prevent urologic complications, certain general principles should be used as a guide. First, a low-pressure reservoir is necessary to prevent deterioration of the upper urinary tract. McGuire et ~1.~~ have stressed the use of leak-point pressure to identify the population at risk for upper urinary tract damage. Bauer and associates1x29 have shown that the presence of dyssynergia of the external urinary sphincter is associated with a high probability of urinary tract deterioration. Thus, examining the infant carefully for evidence of dyssynergia and high bladder pressures should be a priority Progressive hydronephrosis, likewise, is considered an ominous finding and predictive of renal injury if not promptly addressed by medical or surgical intervention or both.29-31 Urodynamic evaluation is performed after surgical closure of the back when the infant can be placed in the supine position. This is ordinarily done before discharge from the hospital; however, the exact timing may vary among centers.2s,29,32 Some centers may wish to delay urodynamic evaluation because a number of patients may experience “spinal shock” during this time. In our experience of 48 infants evaluated in this manner, 13 (27%) demonstrated this finding.24 The remaining 35 (73%) had detrusor hypertonicity or sphincter dyssynergia, or both. Our recommended treatment algorithm is presented in Figure 3. We perform fluoroscopically monitored voiding cystometrography with room temperature radiopaque contrast media (17%) and concurrent perineal electromyography with surface electrodes in the fully awake neonate with a 5 or 8 F feeding tube. This baseline evaluation is designed to establish the pattern of both bladder and sphincteric function and is interpreted together with a review of the ultrasound to define initial management. 33 Sonography is performed to detect hydronephrosis. If the hydronephrosis results from vesicoureteral reflux, it is detected on fluoroscopy during urodynamic assessment, and static images can be obtained to grade the severity. Hydronephrosis is further evaluated with nuclear renography UROLOGY”

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FIGURE

3.

phy; EMG

Treatment algorithm = electromyography;

for newborn with spinal C/C = clean intermittent

TREATMENT

Our current approach is to take both urodynamic and sonographic findings into consideration and to intervene to protect against renal deterioration.24 This is contrary to a recent report advocating observation by ultrasound and urinalysis alone, suggesting more in-depth evaluation only if clinical deterioration occurs.31 We believe, however, that a more aggressive approach is warranted. When urodynamic results demonstrate a high-pressure bladder or one with reflex contractions, intermittent catheterization with or without anticholinergic medication can be implemented easily and safely in the neonatal period. If this is done immediately after initial back closure, renal injury may be prevented.1,24,34*35 A consistent policy of intermittent catheterization also provides nursing staff with an effective plan during this often stressful period when their concentration is divided between care of this complicated postoperative patient and care of the parents. Furthermore, we have found that parental acceptance of, and compliance with, clean intermittent catheterization appears to be far greater if it has been used consistently from birth. Certainly, it is far easier to stop this form of care after diagnostic evaluation suggests it is unnecessary than to implement it after the parents may have become accustomed to their child voiding “normally.” Similar aggressive forms of management have also been proposed by other authors. 24,29,36Furthermore, even with aggressive treatment of the patients, renal deterioration has occurred in 5%. LONG-TERM

MANAGEMENT

The goal in the long term is to preserve renal function while simultaneously achieving continence. This is accomplished by maintaining a urinary reservoir with low pressure and adequate volume, using anticholinergic medication when necessary (as defined by the results of the urodynamic studies). As an adjunct to clean intermittent catheterization, pharmacologic or surgical intervention directed to the bladder or sphincter (or both) may be required. Additional uROL~Y@ 46 (31,1995

dysraphism. U/S = ultrasound; catheterization.

CMC

= cystometrogra-

management issues include vesicoureteral reflux, bacteriuria, bowel irregularities, spinal cord tethering, sexual dysfunction, and problems with socialization. BLADDERFUNCTION

Increased bladder pressure and inadequate capacity may be manifested as incontinence, hydronephrosis, urinary tract infection, and occasionally suprapubic discomfort. For 35 of the 48 children in our initial series, medical therapy with anticholinergic medication (such as oxybutynin 0.1 mg/kg 3 times per day), coupled with intermittent catheterization, was sufficient to provide both a low bladder pressure and continence.24 In some children, higher doses may provide additional detrusor relaxation with enhanced continence. If side effects arise, intravesical instillation can be used.37,38 When medical therapy fails to achieve adequate low-pressure capacity, surgical enlargement may be achieved by detrusor myotomy or augmentation cystoplasty. In the infant who has progressive urinary tract deterioration despite maximal medical therapy, a temporary vesicostomy may prove most effective39 (Fig. 4). The most common surgical approach to the small noncompliant bladder is augmentation with intestinal segments.40,41 Small and large bowel have been used effectively, but we have chosen to rely primarily on the stomach42 (Fig. 5), which has several distinct advantages. First, it is readily available and provides good capacity to the native bladder. Second, the stomachs ability to secrete acid helps correct the chronic acidosis of renal dysfunction, which is present in some of these children. In contrast, virtually all patients in whom the small bowel or colon is used have chronic acidemia, which is especially pronounced in those with renal impairment. Finally, the low pH and near absence of mucus production appear to help decrease infection, although this has not been systematically studied. Mucus, which is present in large quantities when other segments of the bowel are used (especially colon), can plug catheters and thereby prevent 297

FIGURE 4. Vesicostomy (Blocksom technique) using the dome of the bladder and placed close to the umbilicus.

FIGURE 5. (A) A small-capacity, high-pressure fida. (B) Gastric augmentation segment (Cl with to the appendix (which is immediately available der with the suprapubic tube. (Cl Postoperative

298

adequate bladder emptying, especially in boys in whom catheter size is limited. With our gastric patch, we attempt to exclude all antral tissue to prevent the occurrence of the hematuria/dysuria syndrome, which is related to acid production by the gastric segment. Although this syndrome re portedly occurs in up to 36% of patients with gas tric augmentation,43 our avoidance of the antra segment and routine use of intermittent catheter ization have resulted in a much lower incidence Detrusor myotomy (also known as autoaug mentation) is an alternative to bowel augmentation and increases bladder capacity by interrupting the continuity of the smooth muscle layer, allowing the mucosa to protrude in a fashion similar to a bladder diverticulum.44 Information on long-term success with this technique is limited, but detrusor compliance and bladder capacity are good in the short term. This procedure may be an attractive alternative to the use of bowel if longterm results are favorable. Most recently, the dilated ureter attached to a nonfunctional renal unit has been used as a patch. As this segment is usually massively dilated, it lends itself nicely to augmentation.45 We have also had good short-term results. When the anatomy is favorable, this is an especially attractive alternative because it allows for placement of a urothelium-lined structure onto the bladder and also avoids both the interruption of the bowel and its placement in continuity with the urinary tract.

bladder and vessel loop for use as cystogram

high-grade reflux in a 5-year-old child with spina biunder the right gastroepiploic vessels. Arrows point a catheterizable stoma if necessary) and native bladshowing normal-appearing, large-capacity bladder. UROLOGY”

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FIGURE

6.

noncompliant, (C) Appearance

CONTINENCE

(A) Radiographic appearance of bladder before insertion of artificial urinary sphincter. low-capacitu bladder with left vesicoureteral reflux, which developed after placement after’ileocistoplasty augmentation.

MECHANISM

Urinary continence that is related to inadequate outlet resistance rather than inadequate storage may occasionally be amenable to control by alpha-adrenergic medication or, in certain circumstances, by direct stimulation of the pudendal nerve.‘” Most often, however, bladder outlet resistance will be improved only by surgical manipulation. This may involve periurethral injection of collagen or Teflon, bladder neck suspension or sling procedures, placement of an artificial urinary sphincter, or open reconstruction of the bladder outlet. The current experience with injection therapy is limited to a few centers and, although there are reports of up to an 88% improvement in continence, long-term results are lacking at this time.47 The fascial sling, with and without bladder neck reconstruction, is reportedly successful in 70% of patients, especially girls, and may be supplemented by collagen injections in those who experience only partial improvement.48 Our primary approach to poor sphincteric function has been the implantation of the artificial urinary sphincter at the bladder neck in both girls and boys. Our success rate is about 90%, which parallels that reported in the literature.49s50Rates of device failure have diminished with technological improvements, but removal is still required in approximately 12% of cases, primarily as a result of erosion of the urethral cuff.51 One significant complication is the conUROLOGY”

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(B) “Hostile,” of sphincter.

version of a once-compliant bladder to a noncompliant hostile reservoir (Fig. 6), which we have observed in 4 of 36 patients (11%). Although this is likely a response by the detrusor to the increased outlet resistance, the mechanism is still undetermined, and predictive factors are unavailable. For best results, only patients with normal bladder capacity and compliance should be selected for sphincteric implantation52; alternatively, augmentation should be performed simultaneously. CONTINENT

STOMAS

After augmentation of the urinary bladder, catheterization is required to facilitate complete drainage. In some patients, especially those who are wheelchair bound, those with severe scoliosis or lordosis, or those who cannot see or reach the urethra, a catheterizable, continent abdominal stoma may be created to provide an easily accessible route of bladder emptying.53-56 This may be created with a variety of sources, including appendix, fallopian tube, a segment of nonfunctioning ureter, tapered stomach, ileum, or colon. We have found this to be a particularly useful technique in the overweight patient in whom independent urethral catheterization can be extremely difficult. Additionally, in patients who have urethral sensation (particularly boys) in whom selfcatheterization may not be well tolerated, a catheterizable stoma can restore independence and adherence to a treatment regimen. 299

VESICOLJRETERAL REFLUX

Between 40% and 65% of patients with myelomeningocele will have vesicoureteral reflux (VUR).57,58 Often, this is secondary to increased intravesical pressures resulting from detrusor-external sphincter dyssynergia or a poorly compliant bladder. Primary reflux can also be present.5g,60 Treatment is directed toward improvement of storage and elimination of urine, usually by instituting intermittent catheterization and pharmacologic agents. Persistent reflux must then be managed on an individual basis. If surgical intervention is undertaken to improve capacity or continence, it is prudent to consider reimplantation at that time. In the absence of symptomatic urinary infection or renal scarring, low-grade reflux may require only surveillance. 57,58 Should surgical intervention become necessary, a minimally invasive antireflux procedure may be the best first choice. If experience with collagen or other injectable substances proves both efficacious and less morbid, these may become first-line therapy in patients who otherwise have satisfactory lower urinary tract function. Asymptomatic bacteriuria is found in many children with spinal dysraphism, especially those who perform clean intermittent catheterization. Not all these patients require antibiotic therapy or prophylactic suppression. In the absence of VUR, there is little risk of renal scarring.61 Therefore, we do not recommend treatment of asymptomatic bacteriuria unless the patient has documented reflux or a history of febrile urinary tract infection. PRESERVATION OF RENAL FUNCTION

Although different aspects of the urologic treatment of children with myelodysplasia may be emphasized at different points in their lives (such as continence, sexual function, ease of catheterization), the ultimate challenge is to maintain normal upper urinary tracts by preventing renal injury As has already been noted, elevated detrusor pressures and recurrent urinary tract infections are the primary risk factors for renal deterioration and may be prevented by appropriate care of the lower tract.30Jj2 Additionally, injury may occur after ureteral reimplantation if postoperative elevation of bladder pressure is undetected.63 Two difficulties are encountered when attempting to evaluate renal injury First, serum creatinine values and ultrasound imaging do not provide a sensitive measure of early renal injury, as changes may arise only after significant renal damage. A more accurate measure of early renal insult may be obtained with renal scintigraph$j4 The second problem arises because frequently only children with symptoms or progressive hydronephrosis 300

are selected to undergo renal scans. If investigators reserve these studies for only the clinically symptomatic child, the prevalence of renal injury may be artificially low. With this in mind, we obtain dimercaptosuccinic acid renal scans as a baseline in children who have not been evaluated in the neonatal period; subsequently, these are repeated as often as indicated by our noninvasive studies or clinical parameters. We routinely perform renal ultrasound and urinalysis every 3 months for the first year of life and every 12 months thereafter in all cases, as well as at the time of any change in status (incontinence, infection, problems with catheterization). With these guidelines, 27 of 158 children (17%) enrolled in our spinal defects clinic have been found to have renal scarring and only 3 (2%) have experienced renal deterioration. The rates of renal scarring and renal failure in the literature are 16% and 12%, respectively.58,65 BOWEL MANAGEMENT

The management of fecal elimination can be a significant challenge to patients and caregivers. All patients require intensive regulatory programming with cathartics or enemas. The involvement of pediatric gastroenterology is useful. For patients in whom conservative management fails, creation of a continent abdominal conduit to the right colon may enable antegrade delivery of a large-volume enema to clear the colonic contents.66,67 Experience with this technique is limited, but it may offer promise to severely refractory cases. SEXUAL FLJNCTION AND FERTILITY

Because of attention to the care of life-threatening neurologic and infectious complications of spinal dysraphism, these children may expect to enjoy a near-normal life. Therefore, sexual function, which previously was of little concern, is now a subject of importance to our adolescent and adult patients. The majority of adults with myelomeningocele report being sexually active.68 Adolescents, however, have more than the usual problems of developing a sexually desirable identity when concerns about bowel or bladder continence persist into the teenage years. 6g For this reason, we strongly encourage measures to improve continence before the onset of puberty, which commonly comes early in female myelodysplastic patients.6g As their caregivers, we should remember to provide extra consideration to our adolescent patients, as they frequently will have no role model for their eventual sexual activities and need an open dialogue to support their growth and independence. Fertility in males with myelodysplasia is less likely than in the general population, with only 105 reported cases in the literature. In fact, in one study, only 25% of patients were able to achieve UROJDGY’

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FIGURE 7. (A) Small hypertrophic bladder with high-grade reflux in a 1O-year-old girl with tethered cord who presented with diurnal incontinence. (B] After surgical untethering, she was treated with anticholinergic medication and intermittent catheterization. Note cessation of reflux and normal appearance of bladder.

spontaneous erection. 7o However, this differs from another report in which 9 of 12 patients were able to achieve erections, 6 were sexually active, and 1 patient had fathered a child.68 Each patient must be approached individually, with a goal toward maximizing his available function, and counseled regarding the possibility of paternity Modern treatment of impotence and infertility may greatly improve the possibilities for these patients.

OCCULT

SPINAL

DYSRAPHISM

Sometimes defects of the spinal cord may not be apparent on physical examination and will be manifested only after the onset of neurologic, urologic, or orthopedic problems. Occasionally, the only clue to an underlying spinal abnormality is a prominent sacral dimple or sinus tract, a tuft of hair or prominent pigmentation, or presence of a lipoma. 26,71 Any one of these signs should prompt further evaluation. A variety of abnormalities of the spinal cord may be occult (Table I). These should be differentiated from spina bifida occulta, which is found in 10% of the normal population and is not generally associated with spinal cord pathologic conditions. Many of the occult dysraphic states are associated with tethering of the spinal cord. Primary tethered cord is characterized by a short, thickened filum terminale, which prevents the ascent of the conus medullaris during development. Secondary causes of cord tethering are numerous and most commonly include postsurgical scarring with adhesion of the cord to the surrounding dura, intraspinal lipoma, and diastematomyelia. The presenting signs and symptoms in these patients are often insidious. New onset of urinary inuROLcGY@ 46 (31, 1995

continence, changes in voiding pattern, or urinary tract infection in an individual who has been voiding normally or who has a known diagnosis of spina bifida suggests the possibility of such a process. 72,73 If occult spinal dysraphism is suspected in the neonate or infant, ultrasound examination can reliably reveal low position and a nontapered, bulbous appearance of the conus, dorsal location of the cord within the bony canal, solid or cystic masses in the distal canal or soft tissue of the back extending toward the canal, patulous distal thecal sac, and a thick filum terminale.74 Magnetic resonance imaging can follow ultrasound screening to assess spinal cord involvement more accurately It is the diagnostic procedure of choice in older children in whom bone maturation precludes accurate sonography.71,75 Whether early neurosurgical intervention is efficacious in ameliorating neurovesical dysfunction by relieving spinal cord compression or tethering remains controversial. Conditions such as lipomeningocele may benefit from early intervention (before 1.5 years), which may possibly prevent or reverse the neuropathic insult.76 At our center, we performed urodynamic evaluations in 18 patients with the tethered spinal cord syndrome before and after untethering of the cord. Initially, we documented a flaccid bladder in 9 patients (5 with supersensitivity to bethanechol), an uninhibited bladder in 5, mixed bladder dysfunction in 2, and normal function in 2.77 Repeat urodynamic studies were performed in 15 patients at least 6 months after release of the tethering. Of 8 patients with flaccid bladders studied postoperatively, 6 had significant changes: 2 had become normal, 2 had limited contractions, and 2

301

had evidence of upper motor neuron abnormalities. All 4 patients with uninhibited bladders who were evaluated preoperatively and postoperatively were improved, and 3 are currently entirely normal. We believe that tethering of the spinal cord should be sought with any change in neurologic, musculoskeletal (weakness, club foot, or scoliosis), or urologic symptoms or findings.78,79 If detected early, it is reasonable to expect a 70% improvement in voiding symptoms and more than 50% resolution of detrusor hyperreflexia.25 Those patients with neuropathic bladders from occult lesions can be managed in the same fashion as those with overt spinal dysraphism. Figure 7 demonstrates such a case in which treatment with intermittent catheterization and anticholinergic medication resulted in dramatic improvement of diurnal incontinence. CONCLUSIONS Urologic care of patients with spinal dysraphism is a formidable task. It requires both anticipation of the potential hazards that might preclude growth into adulthood with continence, preserved renal function, and normal sexuality, as well as a commitment to the minimum of surgical intervention. Early intervention (both diagnostically and therapeutically) and patient education are likely to lead to the most successful outcome. Although labor-intensive, intermittent catheterization with close clinical follow-up should be instituted early to prevent, rather than treat, the complications of neurogenic dysfunction. REFERENCES 1. Bauer SB: Neurogenic bladder dysfunction. Pediatr Clin North Am 34: 1121-1132, 1987. 2. Yen IH, Khoury MJ, Erickson JD, James LM, Waters GD, and Berry RJ: The changing epidemiology of neural tube defects. United States, 1968-1989. Am J Dis Child 146: 857-861, 1992. 3. Omran M, Stone DH, and McLoone P: The Chief Scientist reports....Pattern of decline in prevalence of anencephaly and spina bifida in a high risk area. Health Bull (Edinb) 50: 407-413, 1992. 4. Joseph DB, Bauer SB, Colodny AH, Mandell J, and Retik AB: Clean, intermittent catheterization of infants with neurogenic bladder. Pediatrics 84: 78-82, 1989. 5. Selzman AA, Elder JS, and Mapstone TB: Urologic consequences of myelodysplasia and other congenital abnormalities of the spinal cord. Urol Clin North Am 20: 485-504, 1993. 6. Moore K, and Persaud TV: The Developing Human. Philadelphia, WB Saunders, 1993. 7. Tanikaze S, and Sugita Y: Cystometric examination for neurogenic bladder of neonates and infants. Hinyokika Kiyo 37: 1403-1405, 1991. 8. Milunsky A, Morris JS, Jick H, Rothman KJ, Ulcickas M, Jick SS, Shoukimas P, and Willett W: Maternal zinc and fetal neural tube defects. Teratology 46: 341-348, 1992. 9. Milunsky A, Ulcickas M, Rothman KJ, Willett W, Jick SS, and Jick H: Maternal heat exposure and neural tube defects. JAMA 268: 882-885, 1992. 302

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