Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). For men with NOA, testicular sperm extraction (TESE) is the only method to obtain sperm for assisted reproductive technology (ART). Given the rarity of these sperm and the unpredictable success of subsequent retrieval attempts, cryopreservation of microdissection-TESE-obtained sperm is essential. Effective cryopreservation prevents the need for repeated surgical procedures and supports future ART attempts. After first delving into the physiological and molecular aspects of sperm cryopreservation, this review aims to examine the current methods and devices for preserving small numbers of sperm. It presents conventional freezing and vitrification techniques, evaluating their respective strengths and limitations in effectively preserving rare sperm, and compares the efficacy of using fresh versus cryopreserved testicular sperm.
Humans ; Cryopreservation/methods* ; Male ; Sperm Retrieval ; Azoospermia/therapy* ; Semen Preservation/methods* ; Spermatozoa ; Vitrification

Testicular histology based on testicular biopsy is an important factor for determining appropriate testicular sperm extraction surgery and predicting sperm retrieval outcomes in patients with azoospermia. Therefore, we developed a deep learning (DL) model to establish the associations between testicular grayscale ultrasound images and testicular histology. We retrospectively included two-dimensional testicular grayscale ultrasound from patients with azoospermia (353 men with 4357 images between July 2017 and December 2021 in The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China) to develop a DL model. We obtained testicular histology during conventional testicular sperm extraction. Our DL model was trained based on ultrasound images or fusion data (ultrasound images fused with the corresponding testicular volume) to distinguish spermatozoa presence in pathology (SPP) and spermatozoa absence in pathology (SAP) and to classify maturation arrest (MA) and Sertoli cell-only syndrome (SCOS) in patients with SAP. Areas under the receiver operating characteristic curve (AUCs), accuracy, sensitivity, and specificity were used to analyze model performance. DL based on images achieved an AUC of 0.922 (95% confidence interval [CI]: 0.908-0.935), a sensitivity of 80.9%, a specificity of 84.6%, and an accuracy of 83.5% in predicting SPP (including normal spermatogenesis and hypospermatogenesis) and SAP (including MA and SCOS). In the identification of SCOS and MA, DL on fusion data yielded better diagnostic performance with an AUC of 0.979 (95% CI: 0.969-0.989), a sensitivity of 89.7%, a specificity of 97.1%, and an accuracy of 92.1%. Our study provides a noninvasive method to predict testicular histology for patients with azoospermia, which would avoid unnecessary testicular biopsy.
Humans ; Male ; Azoospermia/diagnostic imaging* ; Deep Learning ; Testis/pathology* ; Retrospective Studies ; Adult ; Ultrasonography/methods* ; Sperm Retrieval ; Sertoli Cell-Only Syndrome/diagnostic imaging*

Nonobstructive azoospermia (NOA) affects about 60% of men with azoospermia, representing a severe form of male infertility. The current approach to manage NOA primarily involves testicular sperm retrieval methods such as conventional testicular sperm extraction (c-TESE) and microdissection testicular sperm extraction (micro-TESE). While combining testicular sperm retrieval with intracytoplasmic sperm injection (ICSI) offers hope for patients, the overall sperm retrieval rate (SRR) stands at around 50%. In cases where micro-TESE fails to retrieve sperm, limited options, like donor sperm or adoption, can be problematic in certain cultural contexts. This paper delves into prospective treatments for NOA management. Gene editing technologies, particularly clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) protein 9 (CRISPR/Cas9), hold potential for correcting genetic mutations underlying testicular dysfunction. However, these technologies face challenges due to their complexity, potential off-target effects, ethical concerns, and affordability. This calls for research to address key challenges associated with NOA management within the clinical settings. This also necessitate ongoing research essential for developing more sensitive diagnostic tests, validating novel treatments, and customizing current treatment strategies for individual patients. This review concluded that the future of NOA management may entail a combination of these treatment options, tailored to each patient's unique circumstances, providing a comprehensive approach to address NOA challenges.
Humans ; Male ; Gene Editing/methods* ; Azoospermia/genetics* ; Sperm Retrieval ; Sperm Injections, Intracytoplasmic ; CRISPR-Cas Systems ; Spermatozoa ; Stem Cells

Except in cases of hypogonadotropic hypogonadism, the use of medical therapy before microsurgical testicular sperm extraction (micro-TESE) is controversial. In some studies, hormone therapy has been shown to improve the possibility of sperm retrieval during micro-TESE and even lead to the presence of sperm in the ejaculate in some cases, thereby obviating the need for micro-TESE. However, their routine use before micro-TESE in cases of nonobstructive azoospermia (NOA) being associated with hypergonadotropic hypogonadism and eugonadism (normogonadotropic condition) has not been supported with robust evidence. In this review, we discuss different types of medical therapy used before micro-TESE for NOA, their risks and benefits, and the available evidence surrounding their use in this setting.
Humans ; Male ; Azoospermia/therapy* ; Sperm Retrieval ; Hypogonadism/complications* ; Microsurgery

To investigate the impact of preoperative serum follicle-stimulating hormone (FSH) levels on the probability of testicular sperm retrieval, we conducted a study of nonobstructive azoospermic (NOA) men with different testicular volumes (TVs) who underwent microdissection testicular sperm extraction (micro-TESE). A total of 177 NOA patients undergoing micro-TESE for the first time from April 2019 to November 2022 in Shenzhen Zhongshan Obstetrics and Gynecology Hospital (formerly Shenzhen Zhongshan Urology Hospital, Shenzhen, China) were retrospectively reviewed. The subjects were divided into four groups based on average TV quartiles. Serum hormone levels in each TV group were compared between positive and negative sperm retrieval subgroups. Overall sperm retrieval rate was 57.6%. FSH levels (median [interquartile range]) were higher in the positive sperm retrieval subgroup compared with the negative outcome subgroup when average TV was <5 ml (first quartile [Q1: TV <3 ml]: 43.32 [17.92] IU l -1 vs 32.95 [18.56] IU l -1 , P = 0.048; second quartile [Q2: 3 ml ≤ TV <5 ml]: 31.31 [15.37] IU l -1 vs 25.59 [18.40] IU l -1 , P = 0.042). Elevated serum FSH levels were associated with successful micro-TESE sperm retrieval in NOA men whose average TVs were <5 ml (adjusted odds ratio [OR]: 1.06 per unit increase; 95% confidence interval [CI]: 1.01-1.11; P = 0.011). In men with TVs ≥5 ml, larger TVs were associated with lower odds of sperm retrieval (adjusted OR: 0.84 per 1 ml increase; 95% CI: 0.71-0.98; P = 0.029). In conclusion, elevated serum FSH levels were associated with positive sperm retrieval in micro-TESE in NOA men with TVs <5 ml. In men with TV ≥5 ml, increases in average TVs were associated with lower odds of sperm retrieval.
Humans ; Male ; Azoospermia/surgery* ; Sperm Retrieval/statistics & numerical data* ; Adult ; Follicle Stimulating Hormone/blood* ; Retrospective Studies ; Testis/pathology* ; Microdissection ; Organ Size

Infertility, defined as the inability to conceive after 1 year of regular unprotected intercourse, impacts 10%-20% of couples globally. Both male and female factors contribute equally to this condition. Azoospermia, particularly nonobstructive azoospermia (NOA), which affects 10%-15% of infertile men, represents a significant challenge in male infertility. The advent of assisted reproductive technology (ART), specifically microdissection testicular sperm extraction (micro-TESE) followed by intracytoplasmic sperm injection (ICSI), offers a possibility for men with NOA to father biological children. Recent studies have focused on the predictors of sperm retrieval in NOA patients, such as age, testicular volume, and follicle-stimulating hormone (FSH) level. This review aims to explore the limited data on the anatomical characteristics of NOA patients and provide surgical considerations for micro-TESE, thereby enhancing understanding and improving outcomes for this challenging condition.
Humans ; Azoospermia/surgery* ; Male ; Testis/pathology* ; Sperm Retrieval ; Scrotum/pathology* ; Sperm Injections, Intracytoplasmic ; Microdissection

Oncological microdissection testicular sperm extraction (onco-micro-TESE) represents a significant breakthrough for patients with nonobstructive azoospermia (NOA) and a concomitant in situ testicular tumor, to be managed at the time of sperm retrieval. Onco-micro-TESE addresses the dual objectives of treating both infertility and the testicular tumor simultaneously. The technique is intricate, necessitating a comprehensive understanding of testicular anatomy, physiology, tumor biology, and advanced microsurgical methods. It aims to carefully extract viable spermatozoa while minimizing the risk of tumor dissemination. This review encapsulates the procedural intricacies, evaluates success determinants, including tumor pathology and spermatogenic tissue health, and discusses the implementation of imaging techniques for enhanced surgical precision. Ethical considerations are paramount, as the procedure implicates complex decision-making that weighs the potential oncological risks against the profound desire for fatherhood using the male gametes. The review aims to provide a holistic overview of onco-micro-TESE, detailing methodological advances, clinical outcomes, and the ethical landscape, thus offering an indispensable resource for clinicians navigating this multifaceted clinical scenario.
Humans ; Male ; Azoospermia/therapy* ; Testicular Neoplasms/pathology* ; Sperm Retrieval ; Microdissection/methods* ; Testis/surgery*

Since the early days of assisted reproductive technology (ART), the importance of sperm processing, employed to separate the motile, morphologically normal sperm from the semen, has been shown to be beneficial. The aim of the semen processing technique has been to remove seminal plasma and facilitate capacitation. Additionally, the presence of leukocytes, bacteria, and dead spermatozoa has been shown to be detrimental as it may cause oxidative stress that has an adverse effect on oocyte fertilization and embryo development. Hence, removal of leukocytes, bacteria, and dead spermatozoa is an important step of sperm processing for assisted reproduction. Currently, several sperm processing techniques have been evolved and optimized in the field of assisted reproduction. The requirements for in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and testicular sperm extraction (TESE) are different than those of intrauterine insemination (IUI). The yield of as many motile, morphologically normal sperm as possible is a prerequisite for the success of IVF insemination procedure. In ICSI, where injection of a single spermatozoon into the oocyte is performed by the embryologist, sperm selection techniques play a crucial role in the ICSI procedure. Finally, sperm retrieval in TESE samples with very low number of sperm may be challenging and requires extra care during sample processing. Additionally, sperm cryopreservation is necessary in TESE cases in order to avoid multiple biopsies.
Humans ; Sperm Injections, Intracytoplasmic/methods* ; Male ; Fertilization in Vitro/methods* ; Sperm Retrieval ; Andrology/methods* ; Cryopreservation ; Female ; Spermatozoa

The use of fresh versus frozen spermatozoa in men with nonobstructive azoospermia (NOA) undergoing in vitro fertilization (IVF) has been a debated hot topic among reproductive specialists. Each approach presents distinct advantages and disadvantages, with fresh sperm typically showing superior sperm quality, while frozen sperm offers logistical flexibility and a reliable backup for repeated cycles. This review summarizes the latest advancements in sperm retrieval and cryopreservation techniques, providing practitioners with a comprehensive analysis of each option's strengths and limitations. Comparative studies indicate that, although fresh sperm often has better quality metrics, cryopreservation methods such as vitrification have significantly improved postthaw outcomes, making frozen sperm a viable choice in assisted reproductive technologies (ART). The findings show comparable rates for fertilization, implantation, clinical pregnancy, and live birth between fresh and frozen microdissection testicular sperm extraction (micro-TESE) sperm in many cases, although patient-specific factors such as timing, cost-effectiveness, and procedural convenience should guide the final decision. Ultimately, the choice of using fresh or frozen sperm should align with the individual needs and conditions of patients. This tailored approach, supported by the latest advancements, can optimize ART outcomes and provide personalized reproductive care.
Humans ; Cryopreservation/methods* ; Male ; Sperm Retrieval ; Semen Preservation/methods* ; Azoospermia/therapy* ; Pregnancy ; Female ; Fertilization in Vitro ; Spermatozoa ; Microdissection ; Pregnancy Rate

This review focuses on the diagnostic algorithm for nonobstructive azoospermia (NOA), a significant male factor contributing to infertility. NOA, characterized by the absence of sperm in the ejaculate, requires a systematic diagnostic approach to identify reversible conditions, genetic factors, and prognosis for achieving pregnancy. The diagnostic pathway involves semen analysis and a comprehensive evaluation for hormonal deficiencies, anatomical abnormalities, and genetic factors. The importance of medical history, physical examination, endocrine evaluation, imaging, and genetic testing is emphasized. This review highlights the significance of differentiating NOA from obstructive azoospermia (OA) and outlines key considerations for effective management, including surgical sperm retrieval and assisted reproductive techniques. Testicular biopsy is discussed as a definitive method to distinguish obstructive cases from nonobstructive cases, providing valuable prognostic information. Overall, a thorough and systematic diagnostic approach is essential for the effective management of men suspected with NOA, offering insights into potential treatment options and reproductive outcomes.
Humans ; Azoospermia/therapy* ; Male ; Algorithms ; Semen Analysis ; Testis/pathology* ; Sperm Retrieval ; Biopsy ; Infertility, Male/etiology*