P-089 effect of testis tissue retrieval on “Micro Mapping Testicular Extraction” (MMTE): comparison with microscopic testicular sperm extraction (Micro TESE) in non-obstructive azoospermia (NOA)
Authors: Tai T , Shibasaki S , Takahashi M , Okuyama N , Hattori H , Nagaura S , Yoshinaga K , Koizumi M , Toya M , Hashimoto T , Igarashi H , Kyono K 
Published: June 2023

Abstract

Study question
Is a new sperm retrieval method, Micro Mapping Testicular Extraction (MMTE) comparable to that of Microscopic testicular sperm extraction (Micro TESE)?

Summary answer
MMTE is comparable to that of Micro TESE regarding sperm retrieval rate (SRR). It can reduce tissue damage and improve intracytoplasmic sperm injection (ICSI) results.

What is known already
Micro TESE is currently the standard technique for sperm retrieval in NOA. However, the large incision severely damages testicles, complicating repeated Micro TESE, and there is a high risk of testicular atrophy and hypogonadism. New technologies, such as FNA mapping, have also been reported, but these require multiple surgeries, long operation times, and high examination costs. A more accurate and minimally invasive method of sperm retrieval is needed, using a shorter and simpler procedure.

Study design, size, duration
MMTE requires only a small amount of testicular tissue, obtained through multiple needle holes in the tunica albuginea by micro-squeezing under a microscope. Tissue is divided into four testicular areas: ventral-upper, ventral-lower, dorsal-upper, and dorsal-lower, and samples are immediately searched for sperm. If sperm are found, a small incision is made in the area with good sperm and additional tissue is taken under the microscope. If no sperm are found, routine Micro TESE is performed.

Participants/materials, setting, methods
From January to November 2022, 25 NOA cases (35.9+/-4.85 years) with indications for Micro TESE were eligible: 15 idiopathic, 6 gr/gr deletion, 2 Klinefelter’s syndrome, 1 b2b4 deletion and 1 other.
MMTE was performed on 45 testes: 5 unilateral (Group A) cases and 20 bilateral (Group B) cases. If sperm were found, they were cryopreserved and later used or will be used for ICSI.

Main results and the role of chance
After MMTE, sperm were found in all 5 cases in Group A. In group B, sperm were found in 6 cases after MMTE. For those sperm positive 11 cases, additional sampling was performed to gain enough sperm for ICSI.
Micro TESE was performed for the rest of group B (14 cases, 28 testes), in which no sperm was found by MMTE. Of 2 cases out of 14 cases, only a few sperm were found by Micro TESE. No sperm was found in the rest of 12 cases.
As a result, the SRR per patient was 52% (13/25). The weight of tissue sampled was 56.2 mg (15.6-96.2 mg) by MMTE and 224.6mg (206.4-433.2 mg) by Micro TESE, a significant difference. (p &lt; 0.05).
To date, ICSI has been performed in the MMTE-positive 11 cases with a partner (33.8+/-3.4 years). In those cases, the fertilization rate was 62.7% (79/126). The blastocyst rate was 31.7% (40/126), and the pregnancy rate per transfer was 75% (6/8). The total testosterone levels before and 1 month after surgery were significantly reduced only in the cases in which no sperm were found by MMTE.

Limitations, reasons for caution
Two cases that were sperm-positive only by Micro TESE had severe tissue degeneration and tissue was difficult to retrieve from needle holes, so countermeasures were necessary. It is necessary to consider the number of needle holes depending on the size of the testis. The number of cases is still small.

Wider implications of the findings
MMTE can correct tissue just under the albuginea and can cover areas that are difficult to reach with Micro TESE. The sample can be taken through a small incision, so tissue damage is limited to that of Simple TESE, which improves ICSI results by taking sperm from the best areas.

Trial registration number
non applicable