Needle aspiration of the epididymis causes rupture and irreversible damage to the duct. Recurring punctures and needle aspirations of fluid and tissue during Testicular Fine Needle Aspiration (TEFNA) procedure cause irreparable injury and loss of part of the testis' tubules. The hypothesis of this research is that production of sperm from the testis will be improved due to ultrasonically guided Rete Testis needle aspiration. In cases of Obstructive Azoospermia, the Rete Testis is expected to contain a large number of sperm cells. In cases of Non-Obstructive Azoospermia, the investigators can expect to produce sperm cells from aspiration of the Rete Testis, which drains all of the testis' tubules. Furthermore, catheterization of the Rete Testis will allow for the drainage of all testes tubules and for the production of sperm cells created locally in some of the tubules or in parts of them.

The potential advantage of needle aspiration from the Rete Testis is that the procedure will allow for the aspiration from all the testes tubules, as opposed to the standard method of sperm cells production from the testis which samples only some of the tubules. Therefore, it is expected that the procedure suggested in this research will be more efficient than the standard procedures currently in practice. An additional advantage to this procedure is that puncture and aspiration of the tubule network is not expected to block the drainage from the testis, as is the case in aspiration of the epididymis, and it is also not expected to damage the tubules, as is the case in TEFNA and in TESE.

Potential subjects will be Azoospermic men who turn to the IVF unit at Hadassah Ein Kerem and are candidates for a TEFNA treatment.

Only after the men will receive an explanation of the TEFNA procedure and sign a consent form for TEFNA will they be invited to join the study.

After an explanation, the men will sign a consent form (attached) for participation in the study.

The TEFNA procedure in each testis will begin with an ultrasonically guided Rete Testis needle aspiration and washing of the testes tubules. A PP Spinal Needle, of 20-27 Gage and 90mm length, will be used for the ultrasonically guided puncture of the testis and catheterization of the Rete Testis network. After the catheterization, there will be an aspiration, followed by the washing of the testis tubule network in saline used for IV, in a volume of up to 1mL (5), using a 1mL syringe. In men with Obstructive Azoospermia, in case the samples aspirated from the Rete Testis will contain many motile sperm cells (more than hundreds), there will be no need for a TEFNA procedure. In cases where an initial sample of the Rete Testis aspiration will not show many motile sperm cells, the TEFNA procedure will continue on as planned.

The samples from the Rete Testis aspiration will be separately checked for sperm cells from the sample and tissue produced from the TEFNA procedure. The sperm cells produced from the Rete Testis will be used for cryopreservation or fertilization of the ovum of the patient's partner, as is customary in sperm cells attained through the TEFNA procedure. Should sperm cells be produced both from the Rete Testis and from the epididymis or testes, the partner's ovum will be fertilized by the highest quality sperm cells of both sources.

Clinical follow-up on patients will be conducted as customary after testis aspiration.

The patients will be invited six months after the procedure for an ultrasonic check-up of the testes and the Rete Testis.

Inclusion Criteria:

• Men with Obstructive/Non-Obstructive Azoospermia who turned to sperm cell aspiration for IVF and were found suitable for TEFNA and signed consent form.

Exclusion Criteria:

• healthy, non-azoospermic men
• men who are unsuitable for the TEFNA procedure
• men who don't sign the Informed Consent