Plate Objective Scoring Tool (POST); An objective methodology for the assessment of urethral plate in distal hypospadias

Background: Estimation of the quality of the urethral plate (UP) seems to be important when assessing postoperative outcomes of hypospadias repair, but its evaluation remains subjective. We developed an objective model aiming to standardize this assessment, proposing a methodology that could be adopted in future studies designed to evaluate outcomes in the treatment of hypospadias.

Objectives: To evaluate the inter and intra observer reliability of a method to assess the quality of the urethral plate (UP) in hypospadias (POST - Plate Objective Scoring Tool) based on elements of glans characteristics. The reliability of such scoring methodology was compared to an analog accepted tool: the Glans-Urethral Meatus-Shaft (GMS) score. A secondary goal was to compare some characteristics of the UP in GMS score to POST values; aiming to find the threshold between favorable and unfavorable plates.

Methods: Data were prospectively obtained from prepubertal boys who underwent primary hypospadias repair between January 2018 and November 2019. Intrinsic elements of the glanular UP (A: distal midline mucocutaneous junction; B: Glanular knob where the mucosal edges of the UP's edge change direction; C: Glanular/coronal junction) were marked and the AB/BC ratio calculated. The "G" and "M" components of the GMS score were measured electronically three times by four different reviewers with variable pediatric urology experience and blinded to each other values. Favorable UP, according to the GMS score was compared to measurements obtained by POST (AB/BC ratio).

Results: 84 subjects were enrolled. The POST score had an excellent inter-observer agreement for the evaluation of the UP in distal hypospadias (Kappa = 0.832) while the "G" parameter of the GMS correlated poorly among the observers. The Inter-Class Correlation (ICC) analysis to examine the intra-rater agreement value was 0.914 (95% CI 0.87, 0.95.). AB/BC ratio values ranged from 0.6 to 1.6, with a mean of 1.12. The POST cut-off value for "favorable" UP was 1.2 (AUC = 0.62) 95% CI (0.52-0.84) (sensitivity 80% and specificity 60%).

Conclusions: The POST score has higher inter-observer reliability and functions favorably when compared to the GMS. In addition, it demonstrated a high intra-observer reliability among observers of variable experience. Our findings suggest that the POST score adds to evaluation of the UP and could be incorporated as an additional criterion to assess outcomes in distal hypospadias repairs.