Prevalence of spina bifida occulta in patients with functional disorders of the lower urinary tract and its relation to urodynamic and neurophysiological measurements.

OBJECTIVE To determine the relation between neurophysiological abnormalities and the radiological detection of spina bifida occulta in patients with dysfunction of the lower urinary tract. DESIGN Blind assessment and subsequent decoding of mixed batch of abdominal radiographs from patients with and without urological symptoms for evidence of spina bifida occulta and comparison of results with those of previous control series. SETTING Review study among tertiary referrals to an incontinence clinic of a city hospital. PATIENTS One hundred and thirty eight adults with proved urodynamic abnormalities in whom neurophysiological measurements were available. INTERVENTIONS None. END POINT Correlation of neurophysiological abnormalities in lower urinary tract dysfunction with presence and type of spina bifida occulta and level of opening of posterior sacral arcs. MEASUREMENTS AND MAIN RESULTS On decoding radiographs those from patients without urological symptoms showed a similar prevalence of spina bifida occulta to that in the control series (631/2707 controls; 23%). By contrast, patients with urological symptoms had a significantly increased prevalence of spina bifida occulta at S1 and S2 and a higher level of opening of posterior sacral arcs. The increased prevalence of the bony defect was particularly striking in men with urgency and instability and in women with stress incontinence. No significant correlation was found between any particular neurophysiological abnormality and the presence of spina bifida. CONCLUSIONS In patients with dysfunction of the lower urinary tract neurophysiological abnormalities may be associated with congenital dysraphic lesions in the lower lumbar spine and sacrum. There appears to be no direct causal relation between the radiological and neurophysiological abnormalities but the findings suggest a common aetiological factor.