Three-dimensional simulation analysis of microdissection testicular sperm extraction for patients with non-obstructive azoospermia

Background Microdissection testicular sperm extraction (microTESE) is considered the gold standard method of sperm retrieval from patients with non-obstructive azoospermia (NOA). For careful and thorough examination of seminiferous tubules during microTESE, maximizing surface area of the testicles which we are able to search is essential. Objectives To develop a systematic procedure for microTESE to maximize surface area and to achieve high sperm retrieval rate (SRR) in microTESE. Materials and methods We simulated microTESE using three-dimensional (3D) simulation model and analyzed mathematically the sum of the surface area in various methods. The best method obtained from this simulation model was applied to 102 patients with NOA from 2014 to 2018. These new clinical results were compared with those of 56 patients who underwent a previous method of microTESE from 2011 to 2014. Results The mathematical 3D simulation model of microTESE indicated that a longitudinal incision on the tunica albuginea and following transverse slicing incisions of testicular parenchyma maximized the surface area coverage. Forty-six (45%) out of 102 patients who underwent microTESE with the new method had successful retrieval of testicular spermatozoa compared with 16 (29%) of 56 patients with the previous method of microTESE (P = .04). Discussion Transverse resections of parenchyma in our method run parallel to the courses of intratesticular arteries and do not interfere with the blood supply. The small amount of extracted seminiferous tubules was equivalent to that of the previous method, and no patients exhibited post-operative symptoms of androgen deficiency in our study. As for post-operative pain, our new method was comparable with the previous method. Although our study needs a longer follow-up, there will be limited effects on testicular functions. Conclusion Longitudinal incision on the tunica albuginea and following transverse slicing incisions in the testicular parenchyma maximized the surface area and improved the SRR of microTESE.