Can serum Inhibin B and FSH levels, testicular histology and volume predict the outcome of testicular sperm extraction in patients with non-obstructive azoospermia?

A Machine Learning Approach for the Prediction of Testicular Sperm Extraction in Nonobstructive Azoospermia: Algorithm Development and Validation Study

BACKGROUND

Testicular sperm extraction (TESE) is an essential therapeutic tool for the management of male infertility. However, it is an invasive procedure with a success rate up to 50%. To date, no model based on clinical and laboratory parameters is sufficiently powerful to accurately predict the success of sperm retrieval in TESE.

OBJECTIVE

The aim of this study is to compare a wide range of predictive models under similar conditions for TESE outcomes in patients with nonobstructive azoospermia (NOA) to identify the correct mathematical approach to apply, most appropriate study size, and relevance of the input biomarkers.

METHODS

We analyzed 201 patients who underwent TESE at Tenon Hospital (Assistance Publique-Hôpitaux de Paris, Sorbonne University, Paris), distributed in a retrospective training cohort of 175 patients (January 2012 to April 2021) and a prospective testing cohort (May 2021 to December 2021) of 26 patients. Preoperative data (according to the French standard exploration of male infertility, 16 variables) including urogenital history, hormonal data, genetic data, and TESE outcomes (representing the target variable) were collected. A TESE was considered positive if we obtained sufficient spermatozoa for intracytoplasmic sperm injection. After preprocessing the raw data, 8 machine learning (ML) models were trained and optimized on the retrospective training cohort data set: The hyperparameter tuning was performed by random search. Finally, the prospective testing cohort data set was used for the model evaluation. The metrics used to evaluate and compare the models were the following: sensitivity, specificity, area under the receiver operating characteristic curve (AUC-ROC), and accuracy. The importance of each variable in the model was assessed using the permutation feature importance technique, and the optimal number of patients to include in the study was assessed using the learning curve.

RESULTS

The ensemble models, based on decision trees, showed the best performance, especially the random forest model, which yielded the following results: AUC=0.90, sensitivity=100%, and specificity=69.2%. Furthermore, a study size of 120 patients seemed sufficient to properly exploit the preoperative data in the modeling process, since increasing the number of patients beyond 120 during model training did not bring any performance improvement. Furthermore, inhibin B and a history of varicoceles exhibited the highest predictive capacity.

CONCLUSIONS

An ML algorithm based on an appropriate approach can predict successful sperm retrieval in men with NOA undergoing TESE, with promising performance. However, although this study is consistent with the first step of this process, a subsequent formal prospective multicentric validation study should be undertaken before any clinical applications. As future work, we consider the use of recent and clinically relevant data sets (including seminal plasma biomarkers, especially noncoding RNAs, as markers of residual spermatogenesis in NOA patients) to improve our results even more.

Inhibin B-to-Anti-Mullerian Hormone Ratio as Noninvasive Predictors of Positive Sperm Retrieval in Idiopathic Non-Obstructive Azoospermia

Background: The lack of clinically useful biomarkers for predicting micro-TESE outcomes in males with idiopathic NOA. To find clinically reliable serum reproductive hormone markers to predict the outcome of sperm retrieval in men with idiopathic NOA undergoing micro-TESE. Methods: We analyzed the clinical data of 168 men with idiopathic NOA treated with micro-TESE. The clinical predictors of a successful sperm retrieval were put to the test using logistic regression analysis. The clinical net benefit was calculated using a decision-curve analysis, and the predictive power of each variable was assessed using the ROC-derived area under the curve. Result: Between positive group and negative group for sperm retrieval, there was a statistically significant difference in INHB, AMH, and INHB/AMH. AMH, INHB, and INHB/AMH were each independent predictors of successful sperm retrieval, with INHB (OR1.02, p = 0.03), AMH (OR0.85, p = 0.01), INHB/AMH (OR1.08, p < 0.01). The ROC curve determined the optimal cut-off values for serum INHB and INHB/AMH in positive sperm retrieval patients undergoing micro-TESE. 21.51 pg/mL was the cut-off value for INHB. The cut-off value for INHB/AMH was 3.19, which had a 86.3% sensitivity and a 53.8% specificity. Using INHB and INHB/AMH prior to micro-TESE sperm retrieval in idiopathic NOA patients improved the net benefit of positive sperm retrieval, and the net benefit score of INHB/AMH was better than that of INHB, according to decision analysis curves. Conclusion: Serum INHB have predictive value for sperm retrieval outcomes in idiopathic NOA patients undergoing micro-TESE. Combining INHB and AMH, INHB/AMH seems to be a better predictor.

Non-obstructive idiopathic azoospermia vs azoospermia with antecedents of cryptorchidism: ways and probabilities of becoming parents

Background

Non-obstructive azoospermia (NOA) with history of cryptorchidism and idiopathic NOA are the most common forms of NOA without genetic aetiology. Of all patients with one of these two types of NOA, only a few will have a positive TEsticular Sperm Extraction (TESE). Of those with positive extraction followed by sperm freezing, not all will have a child after TESE-ICSI. What are the ways and probabilities of taking home a baby for patients with NOA and a history of cryptorchidism compared with patients with idiopathic NOA?

Results

Patients with idiopathic NOA or NOA and a history of cryptorchidism who underwent their first TESE were included. The patients were divided into two groups: Group 1 was composed of 125 patients with idiopathic NOA and Group 2 of 55 patients with NOA and a history of surgically treated cryptorchidism. Our results showed that more than half of the NOA patients succeeded in becoming parents. The main way to fulfil their plans for parenthood is to use sperm or embryo donation (72%) for men with idiopathic NOA, whereas the majority of men with NOA and a history of cryptorchidism had a child after TESE-ICSI (58.8%).

Conclusions

In our centre, before considering TESE for a patient with NOA, we explain systematically TESE-ICSI alternatives (sperm donation, embryo donation or adoption). As a result, the couple can consider each solution to become parents.

Hormonal markers as noninvasive predictors of sperm retrieval in non-obstructive azoospermia

Non-obstructive azoospermia (NOA) is one of the leading causes of male factor infertility, which results from impaired spermatogenesis. Currently, the sole feasible therapeutic option for men with NOA to father their biologic children is sperm retrieval by testicular sperm extraction (TESE) approaches followed by an intracytoplasmic sperm injection program. Nevertheless, the rate of sperm retrieval from NOA men following TESE has remained as low as 50%, leading to a significant number of unsuccessful TESE operations. Given that TESE is associated with multiple side effects, the prediction of TESE outcome preoperatively can abolish unnecessary operations and thereby prevent NOA patients from sustaining adverse side effects. As the process of spermatogenesis is under the regulation of hormones, the hormonal profile of serum and/or seminal plasma may contain useful information about spermatogenesis status and can potentially predict the chance of sperm retrieval from NOA patients. A large body of literature is available on the predictive capability of different serum and seminal plasma hormones such as FSH, LH, testosterone, inhibin B, AMH, estradiol, prolactin, and leptin in a stand-alone basis or combinational fashion with respect to the TESE outcome. The present review aimed to evaluate the potential of these hormonal markers as noninvasive predictors of sperm retrieval in men with NOA.

Spermatozoa retrieval in azoospermia and expression profile of JMJD1A, TNP2, and PRM2 in a subset of the Karachi population

BACKGROUND

The difficulties encountered in surgical spermatozoa retrieval for intracytoplasmic sperm injection procedure in azoospermic men have stressed the dire need for a robust biomarker for the prediction of spermatozoa retrieval. Data have highlighted the role of JMJD1A (Jumonji domain-containing 1A), a histone H3K9 demethylase, and other nuclear proteins, protamines (PRM) and transition nuclear proteins (TNP), as biomarkers in male infertility.

OBJECTIVE

To access successful spermatozoa retrieval at the time of intracytoplasmic sperm injection by evaluating the mRNA expression profile of JMJD1A, TNP, and PRM in testicular tissue.

MATERIALS/METHODS

About 100 azoospermic patients, who visited the Australian Concept Infertility Medical Center, Karachi for spermatozoa retrieval by testicular sperm extraction or microsurgical testicular sperm extraction participated in the study. mRNA expression of the JMJD1A, TNP1, TNP2, PRM1, and PRM2 genes was determined. Patients were categorized into successful spermatozoa retrieval (n = 42) group and unsuccessful spermatozoa retrieval (n = 58) group.

RESULTS

Azoospermic men in successful spermatozoa retrieval had significantly increased expression of JMJD1A, TNP2, and PRM2. The hormonal parameters - follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone were significantly higher in unsuccessful spermatozoa retrieval. Multivariate analysis showed a significant association between JMJD1A, TNP2, PRM2, and successful spermatozoa retrieval. The area under the receiver operating characteristics curve showed a significant discriminatory ability to predict the spermatozoa retrieval outcome in azoospermic patients for mRNA expression of JMJD1A, TNP2, and PRM2 was 71, 72, and 73%, respectively. The area under the curve for follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone was 0.67, 0.81, and 0.65, respectively.

DISCUSSION

Our study demonstrates that the mRNA expression profile of JMJD1A, TNP2, and PRM2 along with hormonal parameters, is a useful marker to assess the probability of spermatozoa retrieval before intracytoplasmic sperm injection intervention.

CONCLUSION

The probability of spermatozoa retrieval in azoospermic patients is increased when the mRNA expression profile of JMJD1A, TNP2, and PRM2 in testicular tissue is increased.

Predictors of testicular sperm retrieval in patients with non-obstructive azoospermia: a review

Azoospermia is divided into two categories of obstructive azoospermia and non-obstructive azoospermia. Before 1995, couples with a male partner diagnosed with non-obstructive azoospermia had to choose sperm donation or adoption to have a child. Currently, testicular sperm aspiration or micro-dissection testicular sperm extraction combined with intracytoplasmic sperm injection allows patients with non-obstructive azoospermia to have biological offspring. The sperm retrieval rate is significantly higher in micro-dissection testicular sperm extraction compared with testicular sperm aspiration. Additionally, micro-dissection testicular sperm extraction has the advantages of minimal invasion, safety, limited disruption of testicular function, a low risk of postoperative intratesticular bleeding, and low serum testosterone concentrations. Failed micro-dissection testicular sperm extraction has significant emotional and financial implications on the involved couples. Testicular sperm aspiration and micro-dissection testicular sperm extraction have the possibility of failure. Therefore, predicting the sperm retrieval rate before surgery is important. This narrative review summarizes the existing data on testicular sperm aspiration and micro-dissection testicular sperm extraction to identify the possible factor(s) that can predict the presence of sperm to guide clinical practice. The predictors of surgical sperm retrieval in patients with non-obstructive azoospermia have been widely studied, but there is no consensus.

Evaluation of Microdissection Testicular Sperm Extraction (mTESE), Outcomes and Predictive Factors in Ireland: The Gold Standard for Men with Non-Obstructive Azoospermia

Background

Microdissection testicular sperm extraction (mTESE) is the gold standard approach in sperm retrieval in men with non-obstructive azoospermia (NOA). The purpose of the study was to assess the outcomes for Irish men who have undergone mTESE with a single surgeon.

Methods

This is a retrospective, single cohort study. Thirty-four patients underwent mTESE between September 2015 and June 2019. A p<0.05 was considered statistically significant.

Results

In this study, sperm retrieval rate (SRR) was 47.06%. (16/34). The mean age in those who had retrieved sperm at mTESE was 37.9±2.6 years. Johnson Score (JS) and FSH were statistically different between successful and unsuccessful mTESE groups (p=0.017*10^-5 and p=0.004, respectively). Optimal cutoff values for FSH, T and JS were 15 IU/L, 13 nmol/L and 5, respectively. The pregnancy rate was 63.64% (7/11) among men who went on to use mTESE sperm in an ICSI cycle.

Conclusion

The combination of mTESE/Intracytoplasmic sperm injection (ICSI) is the best option available for men with NOA who prefer to achieve paternity using their own DNA. Given the overall SRRs in mTESE, it is imperative to continue research for a predictive model to better counsel azoospermic men regarding the use of mTESE. For this purpose, large, multicenter, randomized controlled trials are needed.

Can preoperative parameters predict successful sperm retrieval and live birth in couples undergoing testicular sperm extraction and intracytoplasmic sperm injection for azoospermia?

Background

We aimed to determine if the success of TESE and live-birth following TESE-ICSI can be predicted from readily available preoperative parameters for couples with azoospermia. Our methodology was as follows, this was a cohort study of couples who attended the fertility service (from 2009-2019) at an NHS hospital in whom the male partner was diagnosed with azoospermia and required conventional TESE with multiple biopsies to obtain sperm. Of 414 men included, 223 had successful TESE and of those 178 have used sperm in ICSI cycle(s). Predictive models were developed using logistic regression. We assessed model performance by internally validated concordance statistics and calibration plots. Successful sperm retrieval was defined as the presence of motile sperm which survived the freeze-thaw process and live-birth defined as delivery after 34 weeks of gestation.

Results

Successful TESE was associated with higher male age and lower FSH. The TESE model discriminated well with a c statistic of 0.81 (0.77-0.85). Live-birth was associated with lower maternal age, earlier ICSI cycle, and lower testicular volume. The live-birth model also discriminated well with a c statistic of 0.70 (0.64-0.76).

Conclusions

These results support the pragmatic counselling of couples diagnosed with azoospermia about the chances of success of the TESE procedure and of biological parenthood prior to surgical intervention. The models help to discriminate between men who have a high or low chance of successful TESE and couples who have a higher chance of achieving a live-birth after successful TESE. This will allow couples to make a better assessment of the balance of risk versus benefit prior to commitment to surgical interventions.

Predictors of surgical sperm retrieval in non-obstructive azoospermia: summary of current literature

Intracytoplasmic sperm injection (ICSI), combined with surgical sperm retrieval (SR) techniques, is the sole option for patients with non-obstructive azoospermia to achieve fertility; however, with suboptimal results. Given the variability in clinical presentation, the potential role of factors that can predict the likelihood of successful testicular SR needs to be clarified. This article summarizes the current evidence concerning the variables predicting SR success in non-obstructive azoospermic patients with spermatogenic failure. For this, we used 60 articles, including 46 original papers and six meta-analyses. Clinical and laboratory factors, as well as adjuvant therapies and surgical retrieval methods, were the factors most commonly investigated. We found that Klinefelter syndrome, Y chromosome microdeletions in regions AZFa/b, and Sertoli cell-only histopathology were associated with reduced SR success. By contrast, testis volume > 12.5 ml, history of cryptorchidism, use of micro-TESE as the sperm retrieval method, and adjuvant therapy were associated with improved SR success. None of the predictors, alone or combined, provide definitive information about the chances of harvesting sperm in men with non-obstructive azoospermia, except for Y chromosome microdeletions in regions AZFa/b. In the latter, SR success is virtually nil. We conclude that SR outcomes in men with non-obstructive azoospermia are difficult to predict based on the existing variables. Although several predictors can be used for patient counseling, their clinical value is limited to either ensure SR success or discourage reproductive urologists from recommending SR to men with non-obstructive azoospermia seeking fertility. A notable exception includes the deletions involving the regions AZFa and/or AZFb of the Y chromosome; the affected patients should be counseled against undergoing SR.

Sperm recovery and ICSI outcomes in men with non-obstructive azoospermia: a systematic review and meta-analysis

BACKGROUND

Factor affecting sperm retrieval rate (SRR) or pregnancy rates (PR) after testicular sperm extraction (TESE) in patients with non-obstructive azoospermia (NOA) have not been systematically evaluated. In addition, although micro-TESE (mTESE) has been advocated as the gold standard for sperm retrieval in men with NOA, its superiority over conventional TESE (cTESE) remains conflicting.

OBJECTIVE AND RATIONALE

The objective was to perform a meta-analysis of the currently available studies comparing the techniques of sperm retrieval and to identify clinical and biochemical factors predicting SRR in men with NOA. In addition, PRs and live birth rates (LBRs), as derived from subjects with NOA post-ICSI, were also analysed as secondary outcomes.

SEARCH METHODS

An extensive Medline, Embase and Cochrane search was performed. All trials reporting SRR derived from cTESE or mTESE in patients with NOA and their specific determinants were included. Data derived from genetic causes of NOA or testicular sperm aspiration were excluded.

OUTCOMES

Out of 1236 studies, 117 studies met the inclusion criteria for this study, enrolling 21 404 patients with a mean age (± SD) of 35.0 ± 2.7 years. cTESE and mTESE were used in 56 and 43 studies, respectively. In addition, 10 studies used a mixed approach and 8 studies compared cTESE with mTESE approach. Overall, a SRR per TESE procedure of 47[45;49]% (mean percentage [95% CI]) was found. No differences were observed when mTESE was compared to cTESE (46[43;49]% for cTESE versus 46[42;49]% for mTESE). Meta-regression analysis demonstrated that SRR per cycle was independent of age and hormonal parameters at enrolment. However, the SRR increased as a function of testis volume. In particular, by applying ROC curve analysis, a mean testis volume higher than 12.5 ml predicted SRR >60% with an accuracy of 86.2% ± 0.01. In addition, SRR decreased as a function of the number of Klinefelter's syndrome cases included (S = -0.02[-0.04;-0.01]; P < 0.01. I = 0.12[-0.05;0.29]; P = 0.16). Information on fertility outcomes after ICSI was available in 42 studies. Overall, a total of 1096 biochemical pregnancies were reported (cumulative PR = 29[25;32]% per ICSI cycle). A similar rate was observed when LBR was analysed (569 live births with a cumulative LBR = 24[20;28]% per ICSI cycle). No influence of male and female age, mean testis volume or hormonal parameters on both PR and LBR per ICSI cycle was observed. Finally, a higher PR per ICSI cycle was observed when the use of fresh sperm was compared to cryopreserved sperm (PR = 35[30;40]%, versus 20[13;29]% respectively): however, this result was not confirmed when cumulative LBR per ICSI cycle was analysed (LBR = 30[20;41]% for fresh versus 20[12;31]% for cryopreserved sperm).

WIDER IMPLICATIONS

This analysis shows that cTESE/mTESE in subjects with NOA results in SRRs of up to 50%, with no differences when cTESE was compared to mTESE. Retrieved sperms resulted in a LBR of up to 28% ICSI cycle. Although no difference between techniques was found, to conclusively clarify if one technique is superior to the other, there is a need for a sufficiently powered and well-designed randomized controlled trial to compare mTESE to cTESE in men with NOA.

Prediction of microdissection testicular sperm extraction outcome in men with idiopathic nonobstruction azoospermia

The aim of the present study is to assess whether the preoperative clinical indicators have an impact on sperm retrieval rate (SRR) in men with idiopathic nonobstructive azoospermia (NOA).We retrospectively studied 241 consecutive men with NOA who underwent microdissection testicular sperm extraction from 2016 to 2019 in the Reproductive Medicine Center, including 154 patients diagnosed with idiopathic NOA. They were grouped according to preoperative indicators, including average testicular volume, follicle-stimulating hormone (FSH), luteinizing hormone, Testosterone (T), and pathology, respectively.The overall SRR was 20.0% (31/155). Men with testicular volume of ≤5 mL had significant higher SRR than men with testes 5 to 10 and ≥10 mL (35.6% vs 12.3%, P = .002; 35.6% vs 16.2, P = .049, respectively). The SRR in men with FSH ≥ 24.8 mIU/mL was significant higher, compared with FSH level of 12.4 to 24.8 mIU/mL (32.6% vs 15.8%, P = .033). Men with Sertoli cell-only had significantly lower SRR than other pathological type (8.1%). Men with an FSH ≥ 24.8 mIU/mL in testicular volume ≤5 mL group had a significantly higher SRR than FSH level of 12.4 to 24.8 mIU/mL in testicular volume of ≤5 to 10 mL group (44.0% vs 11.4%, P = .002). Men with a luteinizing hormone level of 8.6 to 17.2 mIU/mL in testicular volume of 5 to 10 mL group had a poor prognosis, with an SRR of only 6.5%.Severely reduced testicular volume (≤5 mL) and severely increased FSH level (≥24.8 mIU/mL) had the better sperm retrieval outcome, which can be used as independent predictors in men with idiopathic NOA. And a combination of testicular volume and the hormone seemed to be useful in further increase predictive value.

Evaluation of neoadjuvant gonadotropin administration with downregulation by testosterone prior to second time microsurgical testicular sperm extraction: A prospective case-control study

PURPOSE

The aim of this prospective study was to determine whether there is a beneficial role of combining gonadotropin administration with testosterone downregulation in non-obstructive azoospermia patients prior to a second time microsurgical testicular sperm extraction after a negative one.

METHODS

A total of 40 non-obstructive azoospermia men were recruited from a specialized IVF center from 2014 to 2016. Participants were divided equally into two groups: Group A was subjected to testosterone downregulation alone for 1 month and then combined with gonadotropin administration for 3 months prior to second time testicular sperm extraction; Group B (controls) underwent second time microsurgical testicular sperm extraction without prior hormonal therapy.

RESULTS

Mean baseline follicle-stimulating hormone levels of the controls and the cases were 26.9 ± 11.8 and 25.4 ± 8.7, respectively. One month after testosterone downregulation, follicle-stimulating hormone level of the cases was normalized and became 2.4 ± 1.2. There was no statistically significant difference between baseline follicle-stimulating hormone levels of the controls and cases (p = 0.946). Remarkably, two cases were positive after downregulation (10%) and no controls were positive at second testicular sperm extraction (0%). There was no statistically significant difference between sperm retrieval after the second microsurgical testicular sperm extraction in the controls and the cases (p = 0.072).

CONCLUSION

Patients who underwent first time testicular sperm extraction with unfavorable outcome due to different techniques may benefit from testosterone downregulation combined with neoadjuvant gonadotropin administration as it had shown positive sperms retrieval in 2 out of the 20 cases, especially those with hypergonadotropic azoospermia.

Parameters predicting sperm retrieval rates during microscopic testicular sperm extraction in nonobstructive azoospermia

The aim of this study was to investigate the predictive value of the parameters that might have an effect on the success of microscopic testicular sperm extraction (micro-TESE) in infertile patients with nonobstructive azoospermia (NOA). Between 2003 and 2014, 860 patients with NOA were retrospectively analysed. The effect of age, infertility duration, history of varicocelectomy, herniorrhaphy or orchiopexy, presence of solitary testis, tobacco use, previous testicular biopsy results, history of orchitis, usage of human chorionic gonadotropin in the past three months, presence of undescended or retractile testis, presence of varicocele, testicular volume, levels of serum follicle-stimulating hormone, luteinising hormone, and testosterone, presence of Klinefelter syndrome and micro-deletion of Y chromosome on sperm retrieval rates were evaluated. In 45.8% (n = 394) of the patients who underwent micro-TESE, spermatozoon was adequately obtained. Multiple logistic regression analysis demonstrated that previous successful testicular biopsy (OR = 15.346; GA = 5.45-43.16; p < .001) and higher testicular volumes significantly increase sperm retrieval rate in micro-TESE. The testicular volume cut-off as 11 ml was found to be the most significant factor. Although currently testicular biopsy result is not being used as a diagnostic method, it is significantly associated with micro-TESE result.

Results of intracytoplasmic sperm injection performed with sperm retrieved by microscopic testicular sperm extraction in azoospermic patients

OBJECTIVE

The absence of any sperm in the ejaculate is called azoospermia and it is detected in 1% of males and 10-15% of those with infertility complaints. Azoospermia may be due to obstructive (OA) and non-obstructive (NOA) causes. Today, healthy pregnancies can be achieved in azoospermic patients by intracytoplasmic sperm injection (ICSI) performed using sperm retrieved from microscopic testicular sperm extraction (m-TESE). In this study, we examined the sperm retrieval rates with m-TESE in azoospermic patients, the results of ICSI in OA and NOA patients with sperm and the underlying testicular pathologies in patients without sperm.

MATERIAL AND METHODS

Patients who underwent m-TESE at IVF unit of our hospital between January 2005 and April 2017 were retrospectively reviewed. A total of 342 azoospermic patients (117 OA and 225 NOA cases) with regular follow-up were included in the study. In these cases, sperm retrieval and clinical pregnancy rates after ICSI were compared.

RESULTS

In the m-TESE procedure, motile sperm was found in all of the OA patients and in 52.4% (118/225) of the NOA patients. Clinical pregnancy rate in the OA group was 29.9% (35/117) and live birth rate was 25.6% (30/117). In the NOA group, the clinical pregnancy rate was 27.1% (32/118) and the live birth rate was 23.7% (27/118). Histopathologic evaluation was made in 107 cases in the NOA group with no testicular sperm, revealing that 59 cases with germ-cell aplasia (sertoli-cell only syndrome), 42 cases with maturation arrest, and 6 cases with hypospermatogenesis. Postoperative hematoma developed in 3 of m-TESE cases and subsided with conservative treatment.

CONCLUSION

If motile sperm is retrieved with m-TESE application in azoospermic patients, pregnancy resulting in one live birth in about 4 couples who undergo ICSI application can be achieved. In the presence of motile sperm, live birth rates are similar between OA and NOA case with very low complication rates.

DNA Flow cytometric analysis of the human testicular tissues to investigate the status of spermatogenesis in azoospermic patients

A single, rapid and reproducible diagnostic test to predict the type of azoospermia and outcome of sperm retrieval is not yet available. So the feasibility of employing DNA flow cytometry for rapid investigation of the status of spermatogenesis in the patients with azoospermia was investigated. Testicular biopsies of 44 patients with azoospermia undergoing sperm-retrieval surgery and 4 controls were analyzed by flow cytometry to ascertain their testicular germ-cell patterns. The observed germ-cell pattern was further confirmed by RT-PCR analysis of the cell-specific markers and histology for some patients. The patients with Obstructive Azoospermia (OA) exhibited normal spermatogenesis similar to the control fertile patients showing the presence of diploid, double-diploid and haploid cells. The non-obstructive azoospermia (NOA) patients exhibited disrupted spermatogenesis with arrest at the pre-meiotic (only diploid cells present) or meiotic (diploid and double-diploid cells present) stages. The germ-cell pattern, as ascertained by flow cytometry, provided a clear picture of the intra-testicular spermatogenesis and the presence of spermatozoa in the patients’ testes, which was prognostic of their sperm-retrieval. DNA flow cytometry test to ascertain the testicular germ-cell pattern is simple in execution, analysis and interpretation, requires small amount of tissue and provides quantitative data about the status of spermatogenesis in patients. This test would allow comparable analysis of the status of spermatogenesis in patients across clinics and may form the basis for deciding future treatment and intervention strategies.

Heterogenicity of testicular histopathology and tubules as a predictor of successful microdissection testicular sperm extraction in men with nonobstructive azoospermia

Only a few studies evaluate the presence of spermatozoa intraoperatively. The study aimed to assess whether the heterogenicity of testicular histopathology and seminiferous tubules can predict the outcome of microdissection testicular sperm extraction (micro-TESE) in men with nonobstructive azoospermia (NOA).The study comprised a retrospective analysis of 94 patients with azoospermia who were referred from 2016 to 2017. Under optical magnification, they were classified into 2 groups based on the diameter of tubules intraoperatively, namely homogeneous tubules and heterogeneous tubules. Postoperatively, patients were divided into 2 groups of heterogeneous histopathology and homogeneous histopathology according to the 8 histopathological classification subgroups. The sperm retrieval rate was the main outcome.Testicular spermatozoa were successfully retrieved in 27 men (28%). The sperm retrieval rate in those with heterogeneous histopathology was higher than men with homogeneous histopathology (47% vs 12%; P < .001). The sperm retrieval rate of each histopathological subgroup in men who had the heterogeneous histopathology was higher, compared with the homogeneous histopathology (Sertoli cell only [SCO]: 30% vs 6%; maturation arrest [MA]: 38% vs 0%; tubular hyalinization: 42% vs 20%, respectively). Under the optical magnification, the sperm retrieval rate was significantly higher in men with heterogeneous vs homogeneous tubules (65% vs 15%, P < .001). Moreover, the sperm retrieval rate of the contralateral testicular was higher in men who had heterogeneous tubules, compared with the homogeneous tubules (25% vs 3%; P = .036).Heterogenicity of histopathology is an effective predictor in men with histopathological information available from a previous diagnostic biopsy or conventional TESE attempt preoperatively for successful sperm retrieval. Homogeneous tubules seem beneficial for some patients to perform a limited (superficial) contralateral micro-TESE after no spermatozoa were identified initially.

Relevance of testicular histopathology on prediction of sperm retrieval rates in case of non-obstructive and obstructive azoospermia

Introduction:

The aim of our research was to establish the relevance of testicular histopathology on sperm retrieval after testicular sperm extraction in patients with non-obstructive azoospermia and in patients with obstructive azoospermia, who already underwent a previous failure testicular fine needle aspiration.

Methods:

We evaluated a total of 82 azoospermic men, underwent testicular sperm extraction, referring to the Assisted Reproductive Technology Centre of the University of Florence, Italy between January 2008 and March 2017. A general and genital physical examination, scrotal and trans-rectal ultrasound, semen analysis, hormone measurements, including follicle-stimulating hormone, luteinizing hormone and total testosterone, were collected.

Results:

Successful sperm retrieval was obtained in 36 men of total (43.9%). Successful sperm retrieval was 29.5% in non-obstructive azoospermia patients, while men with obstructive azoospermia, who, underwent a previous failure testicular fine needle aspiration, had sperm retrieval in 86% of cases. Mean luteinizing hormone was 6.55 IU/L, total testosterone 4.70 ng/mL, right testicular volume 13.7 mL and left testicular volume 13.6 mL. Mean Follicle-stimulating hormone was 13.45 IU/L in patients with negative sperm retrieval and 8.18 IU/L in men with successful sperm retrieval. According to histology, 20.7% had normal spermatogenesis, 35.3% hypospermatogenesis, 35.3% maturation arrest and 8.5% Sertoli cell-only syndrome. Successful sperm retrieval was 88.2% in patients with normal spermatogenesis, 24.1% in the maturation arrest group and 48.27% in patients with hypospermatogenesis, while negative sperm retrieval was reported in Sertoli cell-only syndrome patients. Seven cases with maturation arrest showed a successful sperm retrieval.

Conclusion:

Testicular histopathology after testicular sperm extraction offers important information on prediction of sperm retrieval and can guide the surgeon in choosing the more suitable therapeutic practice.

Anti-Mullerian Hormone-to-Testosterone Ratio is Predictive of Positive Sperm Retrieval in Men with Idiopathic Non-Obstructive Azoospermia

The lack of clinically-reliable biomarkers makes impossible to predict sperm retrieval outcomes at testicular sperm extraction (TESE) in men with non-obstructive azoospermia (NOA), resulting in up to 50% of unnecessary surgical interventions. Clinical data, hormonal profile and histological classification of testis parenchyma from 47 white-Caucasian idiopathic NOA (iNOA) men submitted to microdissection TESE (microTESE) were analyzed. Logistic regression analyses tested potential clinical predictors of positive sperm retrieval. The predictive accuracy of all variables was evaluated using the receiver operating characteristic-derived area under the curve, and the clinical net benefit estimated by a decision-curve analysis (DCA). Overall, 23 (49%) and 24 (51%) patients were classified as positive and negative sperm retrievals at microTESE. While circulating hormones associated to a condition of primary hypogonadism did not predict sperm retrieval, levels of anti-Mullerian hormone (AMH) and the ratio AMH-to-total Testosterone (AMH/tT) achieved independent predictor status for sperm retrieval at microTESE, with a predictive accuracy of 93% and 95%. Using cutoff values of <4.62 ng/ml for AMH and <1.02 for AMH/tT, positive sperm retrieval was predicted in all individuals, with 19 men out of 47 potentially spared from surgery. DCA findings demonstrated clinical net benefit using AMH and AMH/tT for patient selection at microTESE.

Serum testosterone levels and other determinants of sperm retrieval in microdissection testicular sperm extraction

Background

Microdissection testicular sperm extraction (microTESE) has become the standard of care for sperm retrieval in non-obstructive azoospermia (NOA) patients. Understanding the significant determinants of microTESE outcomes may result in improvements in sperm retrieval rates and provide better-informed clinical decisions.

Methods

This is a clinical retrospective study conducted through chart review of 421 NOA patients who underwent microTESE between August 2009 and July 2015 in a tertiary-care referral hospital. Clinical, biochemical and histopathological characteristics were collected. Normal serum testosterone level was defined as testosterone >9.9 nmol/L. Multiple logistic regression was used to identify determinants of microTESE in the studied population. A P<0.05 was considered significant.

Results

Sperms were successfully retrieved in 39.4% of cases. The average testosterone level was 11.51±7.40 and 11.67±6.42 in patients with successful and unsuccessful microTESE, respectively (P=0.820). No significant association was found between serum testosterone level and sperm motility and amount. Of all variables, histological subtype remained to be the most significant determinant of microTESE outcomes in the examined population, with hypospermatogenesis having over a 3-fold higher odd of successful microTESE than sertoli-cell only.

Conclusions

Serum testosterone level appears to have no significant association with microTESE outcomes in NOA. The underlying histological pattern is a significant determinant of the procedure’s success.

Effects of clinical, laboratuary and pathological features on successful sperm retrieval in non-obstructive azoospermia

OBJECTIVE

The study aims to evaluate the correlation of testicular sperm extraction (TESE) and histopathology with various features of non-obstructive azoospermia (NOA) cases who consulted to our university-based infertility clinic, and the probability of prompting couples about TESE success and to investigate the cost reduction chance through cost-beneficial aspects.

MATERIAL AND METHODS

One hundred and twenty-five patients were enrolled in this study. Age, unprotected intercourse period, age of puberty, and concomittant diseases were noted. Testicular volumes were measured. The correlations between genetic test results and serum levels of Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), free testosterone, prolactine were investigated.

RESULTS

The incidence of NOA among infertile men was found to be 15.1%. Median age of the cases was 33.1 years. Decrease in TESE success rate was seen in the group aged >30, and those who practiced unprotected intercourse for more than 10 years. TESE success rate was 40 percent. The required negative correlation between FSH levels, and testicular volume was not observed when the patient had additional diseases and/or genitourinary surgery. FSH and LH levels were significantly different between TESE- positive and negative groups (p=0.006, and p=0.001 respectively). Success rate in bilateral TESE group was 14.2%, and 96% of TESE- negative patients had bilateral TESE. Fifteen of 118 patients had Y chromosome microdeletions. These results were similar in both TESE- positive and negative group.

CONCLUSION

None of the parameters investigated herein predicted succesful TESE outcomes. However, in cases with increased FSH and AZFa/AZFb deletion before application of bilateral TESE, in cases of increased FSH and AZFa/AZFb deletion, detailed information should be given to these patients about low success rates and risk of disease inheritance which may reduce procedural costs. Knowing groups with poor prognosis, may help rearrangement of the appropriation of infertility in health policies.

Predictive factors of successful sperm retrieval on microdissection testicular sperm extraction in Japanese men

Purpose

To evaluate retrospectively the outcomes of microdissection testicular sperm extraction (micro-TESE) in men with nonobstructive azoospermia (NOA) and to identify the parameters predicting successful sperm retrieval in this cohort of patients.

Methods

After excluding patients with normal testicular volume and serum follicle-stimulating hormone (FSH) level who received conventional TESE, this study included 329 consecutive NOA patients undergoing micro-TESE at our institution. The significance of several factors, including age, testicular volume, etiology and serum levels of FSH, luteinizing hormone (LH) and serum testosterone (T), as predictors of successful sperm retrieval, was evaluated.

Results

Of the 329 men included in this series, 246 (74.8 %), 40 (12.2 %), and 43 (13.1 %) were pathologically diagnosed with Sertoli cell only, maturation arrest, and hypospermatogenesis, respectively. Spermatozoa were retrieved in 97 (29.5 %) of these 329 men by micro-TESE. Older age and non-idiopathic etiology were significantly associated with the probability of successful sperm retrieval; however, there were no significant effects of testicular volume as well as serum levels of FSH, LH, and T on sperm retrieval outcome. Furthermore, Johnsen score of the micro-TESE specimen showed a significant association with whether spermatozoa were successfully retrieved. Univariate analysis of preoperative parameters identified older age and non-idiopathic etiology as significant predictors of successful sperm retrieval, of which only etiology appeared to be independently related to successful sperm retrieval on multivariate analysis.

Conclusions

Spermatozoa are significantly less likely to be successfully retrieved by micro-TESE in men with idiopathic azoospermia.

Follicle-stimulating hormone as a predictor for sperm retrieval rate in patients with nonobstructive azoospermia: a systematic review and meta-analysis

Noninvasive parameters for predicating sperm retrieval rate (SRR) are desirables. Follicle-stimulating hormone (FSH) has been an important predictor since the first years of testicular sperm extraction. Recent studies showed continuous interests in FSH, with both pros and cons. Thus, we conducted a meta-analysis to evaluate the diagnostic value of FSH as a predictor for patients with nonobstructive azoospermia (NOA) taking testicular sperm retrieval. Eligible diagnosis tests were identified from electronic databases (Cochrane Central Register of Controlled Trials, Medline, and EMBASE) without language restrictions. The database search, quality assessment, and data extraction were performed independently by two reviewers. The reference standard was the sperm retrieval result. Diagnostic value of FSH were explored by area under receiver operation characteristics (ROC) curve using Review Manager, version 5.1.0 (Cochrane Collaboration, Oxford, UK) and Meta-DiSc, version 1.4. Meta regression will be done if there is heterogeneity. Then, we find 11 tests including a total of 1350 patients met the inclusion criteria. Our pooled analysis showed that the area under ROC curve of FSH was 0.72 ± 0.04. Meta regression analyses showed that region and average age have an influence on the diagnostic value. FSH showed more diagnostic value with patients in East Asia and with younger patients. We concluded that FSH had moderate value in independently predicating SRR in men with NOA (area under curve >0.7). More detailed diagnosis tests should be anticipated in the future to confirm the diagnostic value of other noninvasive parameters.

Inhibin at 90: from discovery to clinical application, a historical review

When it was initially discovered in 1923, inhibin was characterized as a hypophysiotropic hormone that acts on pituitary cells to regulate pituitary hormone secretion. Ninety years later, what we know about inhibin stretches far beyond its well-established capacity to inhibit activin signaling and suppress pituitary FSH production. Inhibin is one of the major reproductive hormones involved in the regulation of folliculogenesis and steroidogenesis. Although the physiological role of inhibin as an activin antagonist in other organ systems is not as well defined as it is in the pituitary-gonadal axis, inhibin also modulates biological processes in other organs through paracrine, autocrine, and/or endocrine mechanisms. Inhibin and components of its signaling pathway are expressed in many organs. Diagnostically, inhibin is used for prenatal screening of Down syndrome as part of the quadruple test and as a biochemical marker in the assessment of ovarian reserve. In this review, we provide a comprehensive summary of our current understanding of the biological role of inhibin, its relationship with activin, its signaling mechanisms, and its potential value as a diagnostic marker for reproductive function and pregnancy-associated conditions.

Predictive factors of successful microdissection testicular sperm extraction

Azoospermia in men requires microsurgical reconstruction or a procedure for sperm retrieval with assisted reproduction to allow fertility. While the chance of successful retrieval of sperm in men with obstructive azoospermia approaches >90%, the chances of sperm retrieval in men with non-obstructive azoospermia (NOA) are not as high. Conventional procedures such as fine needle aspiration of the testis, testicular biopsy and testicular sperm extraction are successful in 20-45% of men with NOA. With microdissection testicular sperm extraction (micro-TESE), the chance of successful retrieval can be up to 60%. Despite this increased success, the ability to counsel patients preoperatively on their probability of successful sperm retrieval has remained challenging. A combination of variables such as age, serum FSH and inhibin B levels, testicular size, genetic analysis, history of Klinefelter syndrome, history of cryptorchidism or varicocele and histopathology on diagnostic biopsy have provided some insight into the chance of successful sperm retrieval in men with NOA. The goal of this review was to evaluate the preoperative factors that are currently available to predict the outcome for success with micro-TESE.

Predictive factors of successful sperm retrieval in azoospermia

INTRODUCTION

Testicular sperm extraction with intracytoplasmic sperm injection is the standard treatment for azoospermia. The objective of this study is to identify predictive factors of successful sperm retrieval.

MATERIALS AND METHODS

Between June 2003 and May 2011, we tried testicular sperm extraction (TESE) in 74 azoospermic patients in the Reproductive Medicine Unit of Son Espases Hospital (Palma de Mallorca). Serum follicle stimulating hormone (FSH) and inhibin B levels, testicular histology, genetic study, presence or not of cryptozoospermia and testicular volume were examined.

RESULTS

Spermatozoa were successfully recovered in 47.2% of the total patients, in 36% of non-obstructive azoospermic patients and in 100% of obstructive azoospermic patients. Low inhibin B and high FSH were correlated to sperm retrieval failure. The cutoff points were determined using ROC curves that were 67 pg/mL for inhibin B and 12.2 mUI/mL for FSH. Spermatozoa were not successfully retrieved in any patient with Y microdeletions in AZFa,b regions. Spermatozoa were successfully retrieved in 100% of the patients with CFTR mutations. The highest sperm retrieval rate was for hypospermatogenesis, followed by maturation arrest and Sertoli-cell-only. Spermatozoa were successfully retrieved in all cryptozoospermic patients. Although using a non-significant test, there seems to be a correlation between higher testicular volume and a higher probability of successful sperm retrieval.

CONCLUSIONS

Except for Y microdeletions in AZFa,b regions, there is no predictive factor of testicular sperm retrieval to rule out a patient for TESE. Lower inhibin B is more related to sperm retrieval failure than higher FSH. Sperm retrieval is possible for all cases of CFTR mutations but in any case of microdeletion Y in AZFa,b. The lack of germ cells is correlated with a high probability of sperm retrieval failure. The presence of cryptozoospermia is correlated with a high probability of sperm retrieval success. We do not find a statistically significant relation between testicular volume and successful sperm retrieval.

A comparison of models for predicting sperm retrieval before microdissection testicular sperm extraction in men with nonobstructive azoospermia

PURPOSE

We developed an artificial neural network and nomogram using readily available clinical features to model the chance of identifying sperm with microdissection testicular sperm extraction by readily available preoperative clinical parameters for men with nonobstructive azoospermia.

MATERIALS AND METHODS

We reviewed the records of 1,026 men who underwent microdissection testicular sperm extraction. Patient age, follicle-stimulating hormone level, testicular volume, history of cryptorchidism, Klinefelter syndrome and presence of varicocele were included in the models. For the artificial neural network the data set was divided randomly into a training set (75%) and a test set (25%) with n1/n2 cross validation used to evaluate model accuracy, and then modeled with a neural computational system. In addition, a nomogram with calibration plots was developed to predict sperm retrieval with microdissection testicular sperm extraction. We compared these models to logistic regression.

RESULTS

The ROC area for the neural computational system in the test set was 0.641. The neural network correctly predicted the outcome in 152 of the 256 test set patients (59.4%). The nomogram AUC was 0.59 and adequately calibrated. Multivariable logistic regression demonstrated patient age, history of Klinefelter syndrome and cryptorchidism to be significant predictors of sperm retrieval (p <0.05). However, follicle-stimulating hormone and testicular volume were not significant by internal validation.

CONCLUSIONS

We modeled a combination of well described preoperative clinical parameters to predict sperm retrieval using a neural computational system and nomogram with acceptable predictive values. The generalizability of these findings requires external validation.

Testicular fine-needle aspiration versus testicular open biopsy: Comparable sperm retrieval rate in selected patients

BACKGROUND

Sperm recovery by testicular fine-needle aspiration (TESA) has resulted in variable sperm retrieval rate (SRR) and is generally considered inferior to open biopsy (testicular sperm extraction [TESE]).

AIMS

To develop a predictive model for SRR by TESA and to identify factors associated with comparable SRR between TESA and TESE.

SETTINGS AND DESIGN

Single-center controlled cross-sectional study on 450 infertile men with nonobstructive azoospermia.

MATERIALS AND METHODS

Clinical, paraclinical, and histological information of patients were gathered. All patients underwent both TESA and TESE in a single operation. Predictors of SRR by TESA were identified, and the accuracy of TESA in predicting the outcome of TESE was determined.

STATISTICAL ANALYSIS USED

Categorical and continuous variables were compared using independent t test and -chi-square test. Logistic regression model was applied to develop a predictive model for SRR by TESA. Receiver Operating Characteristics (ROC) curve analysis was used to determine the accuracy of TESA in predicting TESE outcome.

RESULTS

Sperm retrieval rate for TESA and TESE was 41.8 and 50.9%, respectively (P = 0.04). Age, duration of infertility, testis volume, luteinizing hormone, prolactin, and testosterone did not differ between patients with and without mature sperm in TESA samples. Serum follicular-stimulating hormone (FSH) < 15 IU/l (Exp (B) = 4.8, 95% CI: 1.4-18.5; P = 0.001) and histology of hypospermatogenesis (Exp (B) = 6.4, 95% CI: 2.1-27.4; P < 0.001) were predictors of SRR by TESA. In patients with FSH < 15 IU/l (57.4% versus 59.5%; Area under the curve (AUC) = 0.907) and testicular histology of hypospermatogenesis (68.0% versus 70.5%; AUC = 0.890), the SRR by TESA was predictive of SRR by TESE.

CONCLUSIONS

Serum FSH and testicular pathology were predictors of SRR by TESA. Patients with FSH < 15 IU/l and/or testicular pathology of hypospermatogenesis had comparable SRR by TESA versus TESE.

Surgical recovery of sperm in non-obstructive azoospermia

The development of intracytoplasmic sperm injection (ICSI) opened a new era in the field of assisted reproduction and revolutionized the assisted reproductive technology protocols for couples with male factor infertility. Fertilisation and pregnancies can be achieved with spermatozoa recovered not only from the ejaculate but also from the seminiferous tubules. The most common methods for retrieving testicular sperm in non-obstructive azoospermia (NOA) are testicular sperm aspiration (TESA: needle/fine needle aspiration) and open testicular biopsy (testicular sperm extraction: TESE). The optimal technique for sperm extraction should be minimally invasive and avoid destruction of testicular function, without compromising the chance to retrieve adequate numbers of spermatozoa to perform ICSI. Microdissection TESE (micro-TESE), performed with an operative microscope, is widely considered to be the best method for sperm retrieval in NOA, as larger and opaque tubules, presumably with active spermatogenesis, can be directly identified, resulting in higher spermatozoa retrieval rates with minimal tissue loss and low postoperative complications. Micro-TESE, in combination with ICSI, is applicable in all cases of NOA, including Klinefelter syndrome (KS). The outcomes of surgical sperm retrieval, primarily in NOA patients with elevated serum follicle-stimulating hormone (FSH) (NOA including KS patients), are reviewed along with the phenotypic features. The predictive factors for surgical sperm retrieval and outcomes of treatment were analysed. Finally, the short- and long-term complications in micro-TESE in both 46XY males with NOA and KS patients are considered.

Serum inhibin-B and follicle stimulating hormone as predictors of the presence of sperm in testicular fine needle aspirate in men with azoospermia

OBJECTIVE

Inhibin-B (Inh-B) is produced by Sertoli cells and controls Follicle Stimulating Hormone (FSH) secretion through a negative feedback mechanism. The primary aim of this study was to compare Iotanh-B with FSH as predictors of the recovery of sperm in testicular fine needle aspirate in men with azoospermia.

DESIGN

In 51 men with azoospermia basal values of Luteinizing Hormone (LH), FSH, prolactin and testosterone as well as Inh-B values before and 24 h and 48 h after the administration of 300 IU recombinant human FSH were determined. Testicular Fine Needle Aspiration (FNA) was also carried out. Thirty-one young healthy men were also enrolled in the study as controls.

RESULTS

There was significant difference between men with azoospermia and controls with regard to the basal Inh-B levels [median (interquartile range) 37.2 (36) vs. 103.0 (90) pg/mL, respectively, p=0.003] but not to the stimulated Inh-B levels [40.5 (41) vs. 73.0 (44) pg/mL, p=0.113 at 24 h and 34.3 (34) vs. 82.0 (50) pg/mL, p=0.098 at 48 h)]. The Area Under Curve in Receiver Operating Characteristic curves were similar for Inh-B and FSH (0.610 vs. 0.716, respectively, p=0.151) as far as prediction of sperm retrieval is concerned.

CONCLUSIONS

Basal serum Inh-B values are significantly lower in men with azoospermia compared to controls. However, Inh-B is not superior to FSH in predicting the presence of sperm in testicular fine needle aspirate.

Microdissection testicular sperm extraction: prediction, outcome, and complications

Testicular spermatozoa can be retrieved successfully by the testicular sperm extraction (TESE) procedure and used for intracytoplasmic sperm injection in cases of non-obstructive azoospermia (NOA). The successful application of TESE depends on the identification of seminiferous tubules containing spermatozoa; testicular tubules of patients with NOA are usually heterogeneous, and TESE may not always be successful in these patients. Microdissection TESE with an operative microscope is advantageous because larger, more opaque, and whitish tubules, presumably containing germ cells with active spermatogenesis, can be identified directly. This procedure is currently the best method for the certain identification of sperm, resulting in a high spermatozoa retrieval rate and minimal postoperative complications. The present review considers the surgical procedure, outcome, prediction for spermatozoa retrieval, and postoperative complications of microdissection TESE.

Which is the best sperm retrieval technique for non-obstructive azoospermia? A systematic review

Our objective was to establish which is the best sperm retrieval technique in non-obstructive azoospermia based on the available evidence. To date, no randomized controlled trial has compared the efficiency of these strategies and thus current recommendations are based on cumulative evidence provided by descriptive, observational and controlled studies. Three outcome measures were assessed for the sperm retrieval techniques: sperm retrieval rate (SRR), complications and live birth rate. Twenty-four descriptive studies reporting on the results of testicular sperm extraction (TESE) were encountered. Seven controlled studies that compared microdissection (MD) TESE with conventional TESE and seven controlled studies comparing fine needle testicular aspiration (FNA) with TESE were identified. The mean SRR for TESE was 49.5% (95% CI 49.0-49.9). TESE with multiple biopsies results in a higher SRR than FNA especially in cases of Sertoli-cell-only (SCO) syndrome and maturation arrest. Current evidence suggests that MD performs better than conventional TESE only in cases of SCO where tubules containing active focus of spermatogenesis can be identified. MD appears to be the safest technique regarding post-operative complications followed by FNA. Only three studies could be identified concerning the influence of the sperm retrieval technique on clinical pregnancy and live birth rate, hence no definitive conclusions can be made. However, so far there appears to be no impact of the technique itself on success rates.