Radiographic gapometry score: A simple predictor for surgical approach in pediatric traumatic posterior urethral strictures.
BACKGROUND
Post-traumatic posterior urethral injuries in children are rare events. Their management algorithms are extrapolations from adult literature and they continue to pose a difficult challenge for pediatric urologists. Not much data for age-related feasibility of an end-to-end urethroplasty are available.


OBJECTIVE
This study was designed to validate a simple preoperative radiographic score to predict the type of surgical repair for traumatic posterior urethral strictures in children.


MATERIALS AND METHODS
This retrospective study was conducted in a tertiary care center in northern India between 2000 and 2015. All patients under 15 years with traumatic bulboprostatic stricture disease were included. Preoperative voiding cystourethrogam (VCUG) and retrograde urethrogram (RGU) films were used to calculate the gapometry index (G/U index), defined as the length of urethral gap divided by the bulbar urethral length. This index was then analyzed for two patient groups based on the anatomical approach employed for achieving an end-to-end urethroplasty: group 1, who underwent a simple perineal approach, and group 2, who needed a more elaborate procedure. Statistical analysis was performed with the two-tailed t-test with SPSS version 18.


RESULTS
A total of 38 patients met the inclusion criteria. The age distribution and G/U index for both groups are detailed in the table. The difference in mean length of the urethral gap for both groups was statistically significant (2.1 cm in group 1 vs. 3.6 cm in group 2). There was a direct correlation between the complexity of surgical procedure required to bridge the urethral gap and the G/U index. The overall success for urethroplasty in either group was between 92.3% and 94.6%.


DISCUSSION
Urethral extensibility is more suitable for younger children. This challenges the traditional viewpoint that the transpubic approach for urethroplasty is more favorable in children. No previous study has been cited in literature correlating the gapometry index with the surgical approach for posterior urethral defects. Our results reflect that a preoperative G/U index of 0.44 correlate with a simple perineal repair, whereas an index of above 0.87 indicates the likelihood of needing a more elaborate transpubic approach.


CONCLUSIONS
Preoperative assessment of G/U index in children with traumatic posterior urethral injuries can successfully predict the operative approach and may therefore aid in better management of these patients.