A new method for direct measurement of urethral distensibility and elasticity based on the neurourethroplastic model
Results of uroflowmetry after surgical treatment of hypospadias by excision of the urethral plate followed by tubularization (TIP) are significantly different from normal values although anatomic stenosis is absent. The lesions may be due to regenerative processes in the excision area or abnormal distention of the urethral plate. Some authors believe that the use of an implant may improve distensibility (compliance). The aim of this work was to develop an experimental rabbit model for measuring intraluminal pressure in intact urethra compared with urethra after TIP surgery with the use of an implant or without it. Direct measurement of intraurethral pressure was performed in 23 adult New Zealand male rabbits divided into 3 groups: group 1- controls (n = 9), group 2 - TIP (n=8), group 3 - TIP + dorsal sheet of the prepucial implant. The animals were followed up for 6 weeks and sacrificed thereafter. Pressure values were similarly distributed between all groups, but average values were higher in groups 2 and 3 given 1 ml injection (p < 0.05). Groups 1 and 2 given 2 and 3 ml insufflations were not different in terms of pressure values but their means were lower than in group 3 (p<0.05).. It is concluded that measurement of urethral pressure from distention caused by controlled segmentary insufflations is an efficacious method for the estimation of uretheral reconstruction. The use of an implant in combination with TIP does not cause further decrease of distensibility.