Can we predict urethral length of boys? – An observational study

Abstract

An additional knowledge about normal anatomy of urethra in boys can improve clinical outcome of any urological interventions. This will also reduce catheter related complications like intra vesical knotting and urethral injuries. At present there is no systematic data available which has studied the urethral length of boys. We have done this study to analyse the length of urethra in boys. The aim of the study is to measure the urethral length in Indian children from the age of 1 year till 15 years and plot a nomogram. Furthermore to analyse the influence of anthropometry on urethral length and derived a formula to predict the urethral length in boys. This is a single institution prospective observational study. After obtaining clearance from the institutional review board, a total of 180 children from the age of 1-15 were recruited for the study. The urethral length was measured during Foley's catheter removal. Other data like age, weight, and height of the patient are collected and the obtained values were analysed with SPSS software. The acquired figures were further used to derive formulae to predict urethral length. A nomogram of urethral length based on age was plotted. With collected figures, five separate formulae were derived to calculate the urethral length based on the age, height and weight. Furthermore for day-to-day use we have deduced a formulas to calculate urethral length which are simplified forms of original formulae. The length of urethra of a new-born male is 5cm, which attains 8cm by three years of age and to 17cm by adulthood. There were attempts to measure the urethral length in adults using cystoscopy, Foley's catheter and different imaging techniques like Magnetic Resonance Imaging and dynamic retrograde urethrography. Simplified formulae which has been derived from this study for clinical use is Urethral length=8.7+Age (in year) × 0.55 CONCLUSION: Our results will complement the current anatomical understanding of the urethra. This evades some rare complications of catheterisation and facilitate reconstructive procedures.