Microdissection testicular sperm extraction (micro-TESE) is a microsurgical technique that has transformed the treatment of non-obstructive azoospermia (NOA). Introduced by Schlegel in 1999 (Human Reproduction 14:131–135), it uses an operating microscope to identify and selectively extract the few seminiferous tubules most likely to contain sperm, allowing biological fatherhood for men who were previously considered untreatable.
Why Micro-TESE?
In NOA, sperm production occurs only in scattered, often microscopic foci within the testis. A conventional TESE takes random samples of testicular tissue, which may miss these foci and removes more tissue than necessary. Micro-TESE allows the surgeon to identify larger, opaque tubules under 15–25x magnification – the tubules statistically more likely to harbour spermatogenesis – and extract only those.
Sperm Retrieval Rates – What the Literature Shows
Multiple systematic reviews and meta-analyses demonstrate the superiority of micro-TESE in NOA. Bernie et al. (Fertility and Sterility, 2015) reported that micro-TESE yielded significantly higher sperm retrieval rates compared with conventional TESE and TESA in NOA, with odds ratios favouring the microsurgical approach. Overall sperm retrieval rates of 40–60% have been reported across large series, with variation based on histology and underlying aetiology:
- Hypospermatogenesis: up to 70–80%
- Maturation arrest: approximately 40–50%
- Sertoli cell-only syndrome: approximately 20–40%
- Klinefelter syndrome (47,XXY): approximately 40–50% in experienced centres (Ramasamy & Schlegel, Journal of Urology)
- AZFc microdeletion: approximately 50%
- AZFa or complete AZFb deletions: retrieval is very rare and micro-TESE is generally not advised
The Procedure
Performed under general or regional anaesthesia, micro-TESE involves a single midline scrotal incision. The testis is delivered, and a wide equatorial incision exposes the seminiferous tubules. Under the microscope, the entire testicular parenchyma is methodically examined, and tubules appearing larger and more opaque are selectively harvested. Extracted tissue is immediately processed by an andrology laboratory while surgery continues, allowing feedback during the procedure.
Advantages Over Conventional Techniques
- Higher sperm retrieval rates in NOA
- Significantly less testicular tissue removed (<5% in micro-TESE vs. much more with conventional TESE)
- Better preservation of testicular blood supply and hormonal function
- Lower rates of post-operative testicular atrophy and hypogonadism on follow-up
Pre-Operative Preparation
Optimal outcomes require careful preparation:
- Complete hormonal, genetic, and radiological workup
- Hormonal optimisation (for example with clomiphene, hCG, or aromatase inhibitors) in selected men to maximise retrieval prospects
- Coordination with the female partner’s IVF cycle so that retrieved sperm can be used fresh for ICSI, or cryopreservation if adequate sperm are identified
ICSI Outcomes After Micro-TESE
When sperm are successfully retrieved, ICSI outcomes are largely comparable to those achieved with ejaculated sperm in many series, with live birth rates dependent on partner age and embryo quality. This makes micro-TESE followed by ICSI a powerful combination for men with NOA.
Risks and Recovery
Complications are uncommon when the procedure is performed by experienced microsurgeons. Potential risks include bleeding, infection, transient scrotal discomfort, and, rarely, a decline in testosterone levels. Most men return to routine activity within 1–2 weeks. Long-term follow-up demonstrates that hormonal function is better preserved than with conventional TESE.
For men with non-obstructive azoospermia, micro-TESE in the hands of an experienced reproductive microsurgeon offers the best chance of biological fatherhood while protecting long-term testicular function.
References drawn from peer-reviewed literature including Schlegel PN, Human Reproduction 1999; Ramasamy R, Schlegel PN, Journal of Urology; Bernie AM et al., Fertility and Sterility 2015; Deruyver Y, Vanderschueren D, Van der Aa F, Andrology 2014; European Association of Urology and American Urological Association male infertility guidelines.