Infertility, commonly referred to as sterility in everyday language, is defined as the inability of a couple to conceive after one year of unprotected intercourse. Around 25–30% of infertility cases are due to male factors. In approximately 10% of male factor infertility cases, no mature sperm is found in the ejaculate, a condition medically referred to as azoospermia. About 0.8–1% of men are azoospermic. In most of these patients, the cause is a disorder in sperm production. Rare chromosomal abnormalities should be screened, hormonal tests performed, and if no problems are detected in these tests, TESE (Testicular Sperm Extraction) should be carried out, which involves surgically retrieving testicular tissue to isolate sperm. Studies have shown that in appropriate patients, sperm can be retrieved in 43.7% of TESE procedures. In our clinic, this rate reaches 65–70% with the micro-TESE technique. For patients in whom mature sperm cannot be found even after two TESE attempts, we use a method called ROSI—short for Round Spermatid Injection—which involves using round spermatids, immature precursor sperm cells.
The earliest precursor cells, primordial germ cells, undergo mitosis to form spermatogonia, which in turn undergo further mitosis to become primary spermatocytes. These three precursor cell groups all contain 46 chromosomes and lack the ability to fertilize an egg. Primary spermatocytes then undergo the first meiotic division, reducing their genetic material by half to form secondary spermatocytes with 23 chromosomes. A second meiotic division occurs, producing immature precursor cells known as round spermatids. Round spermatids are the stage just before mature sperm cells and have not yet undergone metamorphosis, the process of structural maturation.
In 30% of TESE specimens from patients with sperm production disorders, round spermatids have been found. This means that even in cases where no mature sperm can be retrieved via TESE, approximately 30% of patients may still achieve pregnancy using the ROSI method. Moreover, pregnancies and children obtained through this method have shown outcomes as healthy as those achieved with normal sperm cells. At Cyprus American IVF Center, with our specialized and experienced Clinical Embryology team, we successfully perform the ROSI technique with high success rates.
Frequently Asked Questions About ROSI Treatment
What is ROSI?
ROSI, or Round Spermatid Injection, is an advanced assisted reproductive technique used in selected male infertility cases. It involves injecting round spermatids, which are immature sperm precursor cells, into an egg during IVF treatment.
Who can benefit from ROSI?
ROSI may be considered for men with azoospermia when no mature sperm can be found in the ejaculate or through TESE or micro-TESE procedures. It is especially relevant for patients with sperm production disorders.
What is azoospermia?
Azoospermia is a condition in which no mature sperm is found in the semen. It may be caused by sperm production problems, hormonal disorders, genetic factors, blockages, or previous medical treatments.
When is ROSI recommended?
ROSI may be recommended when mature sperm cannot be retrieved despite surgical sperm retrieval attempts such as TESE or micro-TESE, but round spermatids are found in testicular tissue samples.
What is a round spermatid?
A round spermatid is an immature male reproductive cell that develops just before becoming a mature sperm cell. It contains half the number of chromosomes needed for fertilization but has not yet completed structural maturation.
How is ROSI different from ICSI?
In ICSI, a mature sperm cell is injected into the egg. In ROSI, an immature round spermatid is injected into the egg when mature sperm cells are not available.
How is ROSI performed?
ROSI is performed during an IVF cycle. Testicular tissue is examined to identify round spermatids, and selected round spermatids are injected into mature eggs in the laboratory. The resulting embryos are then monitored and transferred if suitable.
What tests are needed before ROSI?
Before ROSI, sperm analysis, hormonal tests, genetic and chromosomal evaluations, and surgical sperm retrieval procedures such as TESE or micro-TESE may be required to assess whether any mature sperm or round spermatids are present.
What is TESE?
TESE, or Testicular Sperm Extraction, is a surgical procedure in which testicular tissue is collected and examined in the laboratory to search for sperm cells or sperm precursor cells.
What is micro-TESE?
Micro-TESE is a more advanced surgical sperm retrieval technique performed under microscopic guidance. It may improve the chance of finding sperm in men with sperm production disorders.
Can ROSI help if TESE fails?
Yes. If TESE or micro-TESE does not reveal mature sperm but round spermatids are found, ROSI may offer a possible treatment option for selected patients.
Does ROSI guarantee pregnancy?
No. ROSI does not guarantee pregnancy. Success depends on the presence and quality of round spermatids, egg quality, embryo development, laboratory experience, female fertility factors, and the overall IVF treatment plan.
Is ROSI suitable for every azoospermia patient?
No. ROSI is not suitable for every patient with azoospermia. It may only be considered when round spermatids are identified and when the couple is medically suitable for IVF treatment.
Are babies born after ROSI healthy?
Reported pregnancies and births after ROSI have shown encouraging outcomes, but each case must be evaluated individually. Patients should discuss possible benefits, limitations, and risks with an experienced IVF and embryology team.
Why is laboratory experience important in ROSI?
ROSI requires precise identification and handling of round spermatids, which are much harder to recognize than mature sperm cells. Therefore, the experience of the clinical embryology team is essential for treatment success.
How common is male factor infertility?
Male factor infertility accounts for a significant proportion of infertility cases. In some men, no mature sperm can be found in the ejaculate, and advanced techniques such as TESE, micro-TESE, or ROSI may be considered.
What is the main advantage of ROSI?
The main advantage of ROSI is that it may provide a chance of biological fatherhood for men who do not have mature sperm but still have usable immature sperm precursor cells.
What should couples consider before ROSI?
Couples should understand the diagnostic process, genetic testing, TESE or micro-TESE results, laboratory requirements, possible success rates, treatment limitations, and emotional aspects before starting ROSI treatment.
