Testicular Tissue Sperm Extraction (TESE) Testicular sperm extraction is indicated for patients in whom there is a blockage in the epididymis very near the testis, or a blockage within the ducts of the testes. Sperm are retrieved from the testes and can be used to achieve fertilization of eggs in the laboratory. However, because the numbers of sperm that retrieved is often very low, it is necessary to combine TESE with ICSI.