(1) Percutaneous epididymal sperm aspiration
In addition to retrieving sperm from the epididymis through open microsurgical techniques, percutaneous epididymal sperm aspiration (PESA) is also possible. The advantages to this technique are that it can be performed without surgical scrotal exploration, it can be repeated easily and at low cost, and it does not require an operating microscope or expertise in microsurgery. The procedure as described by Craft et al. has been performed under local or general anesthesia. After induction of anesthesia, the testis is stabilized and the epididymis is held between the surgeon's thumb and forefinger.
A 21-gauge butterfly needle attached to a 20 ml syringe is inserted into the caput epididymis and withdrawn gently until fluid can be seen entering the tubing of the aspiration set (Figure 8).
The tubing is clamped, the 20 ml syringe removed, and the tubing is back flushed with medium. The procedure is repeated until adequate amounts of epididymal fluid with motile sperm are retrieved1. If no sperm are retrieved, as occurs in at least 20% of sperm retrieval attempts, then it is necessary to proceed with MESA, testis biopsy or testicular aspiration.
(2). Percutaneous testicular sperm aspiration
The procedure for percutaneous testicular sperm aspiration is similar to PESA. The procedure has been performed under general or local anesthesia. After induction of anesthesia, the testis is stabilized between the surgeon's thumb and forefinger with the epididymis oriented posteriorly. A 22- or 23-gauge one and one half inch needle attached to a 20 ml syringe is inserted along the long axis of the testis from the inferior pole directed toward the superior pole. The needle is withdrawn slightly and redirected several times in order to disrupt the testicular architecture so that seminiferous tubules can be aspirated. The procedure is repeated until adequate amounts of testicular material are retrieved. The procedure is depicted in Figure 6. For optimal retrieval, a syringe holder is used to provide significant negative pressure for the aspiration. The Franzen hand-grip syringe holder accommodates one disposable syringe and allows aspiration to be performed with one hand while the other hand stabilizes the testis. The Franzen syringe holder is depicted in Figure 9.
Although only sporadic reports of fertilization and pregnancy rates achieved with percutaneously aspirated testicular sperm exist, there are reports on success rates with sperm retrieved from open testicular biopsy and manipulated with IVF/ICSI. One such study reported fertilization and clinical pregnancy rates of 45 and 62 percent for epididymal sperm compared to 46 and 42 percent for testicular sperm, respectively. The ongoing pregnancy rates were 50 and 43 percent for sperm retrieved from the epididymis and testis, respectively. Testicular sperm can also be recovered using fine needle aspiration ( FNA), percutaneous biopsy, or an open technique of testicular sperm extraction (TESE).