PURPOSE: Noninvasive uroflow/EMG can measure EMG lag time - the time interval between the start of pelvic floor relaxation and start of urine flow (normally 2-6seconds).
Intuitively, one would expect that in patients experiencing urgency secondary to DO, the lag time would be short or even a negative value. Therefore, in this study, we sought to determine if short EMG lag time on uroflow/EMG actually correlates with documented DO on UDS.
METHODS: Two separate and distinct cohorts of 50 neurologically and anatomically normal children with persistent LUTS evaluated with uroflow/EMG and VUDS were reviewed. Cohort#1: children selected based on EMG lag time of ≤ 0 seconds on screening uroflow/EMG who subsequently underwent VUDS; Cohort#2: children selected based on the presence of DO on VUDS, whose screening uroflow/EMGs were then reviewed. Correlations between short EMG lag time and VUDS-proven DO were analyzed.
RESULTS: For cohort#1 (30M, 20F; mean age 7.8yr, range 4-19), UDS confirmed the presence of DO in all patients with an EMG lag time of ≤ 0seconds. For cohort#2 (14M, 36F; median age 8.4yr, range 5-18), the average EMG lag time was 0.1 seconds (SD=1.7) and 35 (70%) with UDS-proven DO had a lag time of ≤ 0seconds.
CONCLUSION: In patients with LUTS, an EMG lag time of ≤ 0seconds is 100% predictive of DO. This short EMG lag time has 100% specificity and 70% sensitivity for diagnosing DO (88% if < 2seconds). Thus, diagnosing the presence or absence of DO in most children with LUTS and a quiet pelvic floor during voiding can be done reliably with uroflow/EMG.
Written by:
Combs AJ, Van Batavia JP, Horowitz M, Glassberg KI. Are you the author?
Divisions of Pediatric Urology, Morgan Stanley Children's Hospital of New York - Presbyterian, Columbia University Medical Center.
Reference: J Urol. 2013 Jan 9. pii: S0022-5347(13)00033-5.
doi: 10.1016/j.juro.2013.01.011
PubMed Abstract
PMID: 23313197
UroToday.com Pediatric Urology Section
