Frances M. Dyro

Neurourological Implications of the Changing Approach in Management of Occult Spinal Lesions

Occult lesions of the spine in children are a rare but recognizable cause of neurogenic dysfunction involving the lower extremities, and lower urinary and gastrointestinal tracts. We report the preoperative and postoperative urodynamic findings in 40 children with varying spinal abnormalities. Of these patients 28 were neonates or infants (average age 8.7 months) and 12 were older children (average age 11.7 years). Preoperative urodynamic testing revealed normal function in 18 of 28 children (64 per cent) in the younger age group in contrast to 1 of 12 (8 per cent) in the older age group. Of the 10 infants with abnormal studies postoperative urodynamic findings returned to normal in 6, while 2 others remained abnormal but were improved. In contrast, of 11 older children with abnormal preoperative evaluations 3 (27 per cent) reverted to normal postoperatively. The neurourological changes seen in these occult lesions are variable, may occur at any age, are progressive and are potentially reversible by surgical correction but this reversibility diminishes with age.

Bladder Functional Changes Resulting from Lipomyelomeningocele Repair

From 1986 to 1991, 12 boys and 23 girls underwent surgery for lipomyelomeningocele removal. Of these patients 29 were 15 months old or younger (average age 3 months), while 6 were 4.5 to 19 years old (average age 10 years). Preoperative and postoperative urodynamic studies, including external urethral sphincter electromyography, were done on everyone. All 29 infants had a cutaneous lesion overlying the lower back and 14 had an abnormal neurological examination. Preoperative urodynamic studies were abnormal in 11 patients, consisting of an upper motor neuron lesion in 6, and a mixed upper and lower motor neuron lesion in 5. Postoperatively, 10 of 14 children with an abnormal neurological examination improved, while 9 of 11 with abnormal lower urinary tract function normalized. In 1 of 18 children (6%) with normal preoperative urodynamic studies detrusor-sphincter dyssynergia developed postoperatively. In all 6 older children urinary incontinence developed, and this led to the diagnosis. Everyone had an abnormal neurological examination and abnormal preoperative urodynamic studies. One child had a lower motor neuron lesion, and 5 had a mixed upper and lower motor neuron lesion. Postoperatively, the neurological examination improved in only 1 patient (16%), and the urological symptoms and urodynamic findings improved in another child. Lipomyelomeningocele has a progressive effect on lower spinal cord function because infants tend to present with fewer urinary manifestations and physical findings than older children. Individuals who escape early detection tend to have a more subtle cutaneous abnormality. As a result, older children are more likely to present with urological and neurological complaints. Surgical correction in infancy provides a degree of reversibility not seen in older children. It is imperative that early identification, evaluation and treatment be undertaken to prevent this progression and permanency of neurological changes and urinary dysfunction.

Urodynamic assessment of children with cerebral palsy.

More than a third of the children with cerebral palsy present with dysfunctional voiding symptoms. Clinical evaluation and urodynamic study of cerebral palsy patients were performed to characterize the symptoms, to define the type of neurological deficit and to document its effect on voiding dynamics. We evaluated flow rate, and cystometrographic and external sphincter electromyographic findings in 57 children with cerebral palsy. Upper and lower motor neuron lesions were defined by standard criteria. Of the children 86 per cent had evidence of a pure upper motor neuron injury and 11 per cent manifested electromyographic findings suggestive of incomplete lower motor neuron sphincteric injury. The latter deficit could not be predicted on the basis of clinical neurological findings but it was suggested by a history of neonatal cyanosis. Treatment protocols achieved continence in more than 75 per cent of the children. The voiding dynamics in children with cerebral palsy have not been assessed previously. We have defined the lower urinary tract dysfunction in these patients, and provide a rational and effective plan of management.

The Neurosurgical Implications of Continuous Neurourological Surveillance of Children with Myelodysplasia

Between 1979 and 1990, 148 newborns with myelodysplasia were followed with serial urodynamic studies and neurological assessment. Of the patients 59 (40%) exhibited changes in neurological status by age 5 years, of whom 28 (19%) showed signs of deterioration. Most changes occurred before age 2 years. A total of 22 children underwent repeat neurosurgical exploration because of a change in urethral sphincter innervation (17), deterioration of function of the lower extremities (3), or changes on computerized tomography or magnetic resonance imaging (2). Postoperative urodynamic evaluation demonstrated improvement in 11 children, stabilization in 9 and further deterioration in 2. The earlier that a change was detected and secondary surgery was performed, the better the outcome. These findings indicate that the neurological lesion in myelodysplasia is a dynamic disease process requiring continuous neurological, orthopedic and urodynamic surveillance. Early identification and prompt neurosurgical reexploration seem to arrest and even reverse the neurological deterioration that takes place in a substantial number of these children.

Urodynamic Dysfunction In Walking Myelodysplastic Children

We evaluated urodynamically and radiologically 54 children with myelodysplasia and neurological deficits at or below the S1 level. Baseline urodynamic testing was normal in 13 patients (24%), while 12 (22%) had an upper motor neuron and 13 (24%) had a lower motor neuron type of dysfunction. A total of 7 patients (13%) had a mixed upper and lower motor neuron type, and 9 (17%) had only lower motor neuron dysfunction of the urethral sphincter with a normally contractile bladder. Followup studies varying in time from 1 month to 10 years showed a changing neurourological lesion in 29 patients (54%): 25 deteriorated while 4 improved. Of the 54 children 20 had hydronephrosis and/or vesicoureteral reflux. Incontinence was the major problem in 41 patients (75%), and was managed initially with pharmacological agents and/or clean intermittent catheterization, with 9 of the 41 eventually requiring surgery. Urodynamic assessment reveals a variable picture that does not correlate well with the apparent neurological examination. Despite the low level of the neurological deficit, many children may be at risk for urinary tract deterioration. These findings emphasize the importance of continuous surveillance and appropriate management in this group of myelodysplastic children who have the greatest potential for a normal life.

Refractoriness of urethral striated sphincter during voiding: studies with afferent pudendal reflex arc stimulation in male subjects.

To assess the excitability of the striated sphincter under normal and abnormal conditions, electrostimulation of the periurethral striated sphincter via the dorsal nerve of the penis was done with the patient at rest and during voiding. Monitoring of simultaneous intravesical and intramembranous urethral pressures, and electromyographic responses of the striated sphincter was performed under fluoroscopic guidance in 14 male subjects. The urethral striated sphincter attained a state of relative refractoriness during detrusor contraction (voiding phase) and greater amounts of afferent stimulation were required to elicit sphincter contractile activity compared to the amounts required during resting states. Under conditions of a hyperactive detrusor with synergic voiding, the amounts of stimulation required to elicit striated sphincter responses were higher than those required in normal subjects. On the other hand, under conditions of striated sphincter dyssynergia, minute amounts of afferent stimulation were enough to produce sphincter contraction during voiding.

The Unrecognized Neuropathic Bladder of Infancy

Four infants presented with hydroureteronephrosis and incomplete emptying of the bladder secondary to detrusor-sphincter dyssynergia. None of the patients had other signs suggestive of neurological dysfunction. It is presumed but not proved that these infants manifested a urodynamic reaction in response to a perinatal insult involving the brainstem area. Long-term followup has demonstrated a persistent but nonprogressive neurourological disturbance.

Electrodiagnostic abnormalities in 15 patients with posttraumatic syringomyelia: pre- and postoperative studies

A review of 15 patients with posttraumatic syringomyelia indicates that the most reliable electrodiagnostic criteria for the diagnosis of syrinx are the loss of motor unit numbers with increase in motor unit amplitude and duration and synchronous firing. Prolongation of F wave latency in a previously stable patient is a useful observation. Return of function and improvement of F wave latencies can occur rapidly following decompression of the syrinx. Forty per cent of the patients studied had concomitant involvement of at least one peripheral nerve as one would expect invoking the double crush hypothesis.

Retained Sacral Function in Children with High Level Myelodysplasia

To assess the preservation of sacral function despite denervation higher on the spinal cord in children with myelodysplasia, we examined 151 myelomeningocele patients presenting for urodynamic evaluation from 1980 to 1992 with a lesion at L3 or above on neurological examination. Of the 151 patients 70 (46%) had denervation of the external sphincter on initial evaluation and 81 (54%) had sacral sparing, that is normal or near normal electrical potentials of the external urethral sphincter and/or retained reflexic bladder activity regardless of the presence or absence of sacral reflexes. Of the 81 patients with sacral sparing 57 (70%) had detrusor-sphincter dyssynergia and 21 had synergy or denervation of the sphincter in association with retained detrusor reflexia. Whereas only 18% of children age 1 year or younger with retained sacral function had upper urinary tract deterioration on initial radiological studies (manifested by reflux or hydronephrosis), 57% had deterioration when evaluated after age 1 year. None of the patients without retained sacral function had evidence of upper urinary tract damage at younger than 1 year but 28% of those studied beyond age 1 year had changes. Patients with flaccid lower extremities can retain sacral function, which puts the upper urinary tract at risk of deterioration. Our results show that this risk increases with time.