P-011 Deep testicular tissue dissection is most often required to retrieve testicular sperm in patients with non-obstructive azoospermia undergoing microdissection testicular sperm extraction
Authors: Caroppo E , Castiglioni F , Colpi E.M , Piatti E , Gazzano G , Colpi G.M 
Published: June 2022

Abstract

Study question
How successful is sperm retrieval from the testicular surface of patients with non-obstructive azoospermia (NOA) undergoing microdissection testicular sperm extraction (mTESE)?

Summary answer
Enough good quality sperm for ICSI could be retrieved from the testicular surface in only 33 out of 224 patients (14.7%)

What is known already
Due to the anatomic singularity of NOA, characterized by the heterogeneous distribution of histologically and functionally distinct seminiferous tubules, retrieving enough good quality sperm for ICSI may require a complete testicular dissection. While conventional TESE (cTESE) may reach only the seminiferous tubules located in the testis surface, mTESE allows the nearly complete exploration of the whole testicular parenchyma. This is the reason why mTESE provides better sperm retrieval rates compared to cTESE, according to two systematic reviews and one meta-analysis: the superiority of mTESE compared to cTESE, however, has been challenged by a recent meta-analysis.

Study design, size, duration
Retrospective cohort study on 224 patients, aged 37 (20-54) years, who underwent unilateral (71, 31.7%) or bilateral (153, 68.3%) mTESE from January 2018 through May 2021. 175 patients were naïve for mTESE, while 49 underwent a salvage mTESE following one or more previously failed conventional TESE.

Participants/materials, setting, methods
The testis was opened like a book following a transversal incision of the testis covering two-thirds to three-quarters of its circumference: the entire surface of the testicular parenchyma was explored first in search for dilated seminiferous tubules. If no/ not enough sperm were retrieved, the testis was opened till to be fully bivalve, and the deeper portion of the testicular parenchyma was explored both into hilum direction and orthogonally to the para-equatorial section plan.

Main results and the role of chance
Sperm was retrieved in 114 patients (50.8%), 67 (94.3%) undergoing unilateral and 47 (30.7%) undergoing bilateral mTESE: only 15/153 (9.8%) had their testicular sperm retrieved in the second testis following the unsuccessful sperm retrieval in the first testis, while in the remaining cases sperm had to be retrieved from both testes to obtain enough good quality sperm for ICSI. Histopathology demonstrated Sertoli-cell only syndrome in 65.6% of operated testes, while maturation arrest was found in 19.8%, hypospermatogenesis in 12.6% and hyalinosis in 1.5%. Sperm were obtained from the testis surface in 33 out of 114 patients (28.9%); in the remaining patients a deeper dissection was needed. No difference was seen among patients with sperm found in the surface or requiring deeper dissection in terms of age, testis volume, serum testosterone level, and histopathological subcategories; although serum FSH and LH level were significantly lower in patients with sperm retrieved from the testicular surface, on multivariate logistic regression they were not found to predict the chance of retrieving sperm from the surface (OR 0.96, 95% CI 0.92-1.007, p = 0.104 and OR 0.95, 95% CI 0.85-1.06, p = 0.405, respectively).

Limitations, reasons for caution
the amount of testicular tissue dissected was strictly dependent upon the chance of finding enough sperm for ICSI in the specimens handled by the biologist in the operating room: we cannot exclude that in some patients enough sperm could be obtained from the testis surface following further extensive search

Wider implications of the findings
mTESE is to be preferred to cTESE, since in most patients with NOA seminiferous tubules containing sperm may be found in the deeper portion of the testicular parenchyma. This may be particularly true for patients with unfavorable histopathological patterns, such as Sertoli cell only syndrome or maturation arrest.

Trial registration number
Not applicable