Comprehensive multidisciplinary phenotyping of patients with hypospadias. A pilot study

Hypospadias is an abnormal formation of the urethra, ventral skin, and corporal bodies. Location of the urethral meatus has historically been the phenotypic landmark that defines hypospadias. Nonetheless, classifications following location of the urethral meatus fail to consistently predict outcomes and have no correlation with the genotype. Description of the urethral plate is very subjective and difficult to reproduce. We hypothesize that the use of digital pixel cluster analysis and correlation to histological analysis can provide a novel method to describe the phenotype of patients with hypospadias.

A standardized hypospadias phenotyping protocol was developed. 1. Digital images of the anomaly, 2. Anthropometric assessment of penile dimensions (penile length, urethral plate length and width, glans width, ventral curvature), 3. Classification using the GMS score, 4. Tissue sampling (foreskin, glans, urethral plate, periurethral ventral skin) and H&E analysis by a blinded pathologist. A k-means colorimetric pixel cluster analysis was performed following the same anatomical landmark distribution as the histology samples. Analysis was performed using MATLAB v R2021b 9.11.0.1769968.

A total of 24 patients prospectively enrolled with a standard protocol. Mean age at surgery was 16.25 months Urethral meatus was distal shaft in 7 patients, 8 coronal, 4 glanular, 3 midshaft, 2 penoscrotal. Average GMS score was 7.14 (±1.58). Average glans size was 15.71 mm (±2.33) and urethral plate width 5.57 mm (±2.06). Eleven patients underwent Thiersch-Duplay repair, 7 TIP, 5 MAGPI, and 1 a first stage preputial flap. Mean follow-up was 14.25 months ( ± 3.7 months). Two (8.3%) postoperative complications (1 urethrocutaneous fistula and 1 ventral skin wound dehiscence) were reported in the study period. Eleven (52.3%) patients with histological analysis had an abnormal pathology report. Of those, 6 (54%) had reported abnormal lymphocyte infiltration interpreted as chronic inflammation at the urethral plate. The second most common finding was hyperkeratosis visualized in the urethral plate in 4 (36.3%) and one with reported fibrosis in the urethral plate. K-means pixel analysis demonstrated a k1 mean of 64.2 for reported urethral plate inflammation vs 53.1 for non-reported urethral plate inflammation (p = 0.002) CONCLUSIONS: Current phenotyping of hypospadias using only anthropometric variables can be expanded including histological and pixel analysis correlation. Pixel clustering has a potential for a priori prediction of urethral plate quality beyond the current subjective assessment. A larger cohort will allow identification of possible predictive associations that might impact intraoperative decision-making and surgical outcomes.