Thanks for the question - the anatomy of the prostatic urethra is a bit confusing. There are 4 distinct parts of the urethra - the first 2 are distinct tubes, the 3rd portion traverses the sphincter muscle and finally there is the prostatic urethra. The prostatic urethra is not really a tube per se here, rather it is the potential space that occupies the donut hole of the prostate - thus it can be a circular, slit like or any shaped opening. When surgeons remove prostate tissue they are not disrupting a confined tube, rather they are simply expanding that opening typically into a big circle. In case of a holep that circle is very large as it is takes the prostate to the maximum outer limit (the prostate capsule = rind of orange). Because so much more tissue is removed with Holep it is a more durable case as regrowing tissue to cause more blockage takes longer. On the downside the chance of problems with ejaculation is definitely higher. Some think risk of ED is also higher compared to other less invasive/max tissue removing approaches.