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

Abstract

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.

Keywords: TESE; male infertility; microdissection; non-obstructive azoospermia; simulation; testis.

Figure 1

Mathematical model of the testis, which has an ellipsoid shape with the lengths of each axis denoted as Al, Bl, and Cl, with Al being the longest and Cl the shortest (Al > Bl>Cl). This testis model was placed into the X‐Y‐Z axis with the longitudinal incision parallel to the X‐axis and the coronal and sagittal planes corresponding to the X‐Y and X‐Z planes, respectively

Figure 2

Schematic illustrations of (A) a longitudinal incision on the tunica albuginea and transverse slicing incisions in the parenchyma, (B) a longitudinal incision on the tunica albuginea and sagittal incisions in the parenchyma, (C) a transverse incision on the tunica albuginea and sagittal incisions in the parenchyma, and (D) a transverse incision on the tunica albuginea and coronal incisions in the parenchyma. The width of the sliced piece of testicular parenchyma was assumed to be l

Figure 3

The method to maximize the surface area in microTESE. (A) A long longitudinal incision was made in the tunica albuginea. (B) After the initial incision, the testis was opened by incision to form a bivalved testis. (C) The tunica albuginea was pushed upward turning the parenchyma inside out. (D) Transverse slicing incisions on the parenchyma provided the maximum surface area in microTESE