CONVENTIONAL IN-VITRO FERTILIZATION VERSUS INTRACYTOPLASMIC SPERM INJECTION FOR PATIENTS REQUIRING MICROSURGICAL SPERM ASPIRATION

Intracytoplasmic sperm injection (ICSI) has been successful in cases o f extreme oligoasthenozoospermia in achieving pregnancies via in-vitro fertilization (IVF) with the lowest imaginable sperm counts. In azoos permia caused by congenital bilateral absence of the vas deferens (CBA VD), it has been shown that epididymal spermatozoa can be retrieved in large numbers, but fertilization rates using conventional NF are low. Furthermore, no fertilization has ever been possible using testicular spermatozoa with conventional IVF. In the most extreme case of absenc e of the epididymis, spermatozoa can only be retrieved from macerated testicular biopsy specimens. In such cases, all that can be seen are f ree-floating Sertoli cells with many spermatids attached, and only occ asional spermatozoa per high power field which have only the barest, o ccasional, slightly twitching motion. The objective of the present stu dy was to determine whether ICSI could achieve better results than con ventional IVF with microsurgical aspiration of spermatozoa (MESA). ICS I (using epididymal or testicular spermatozoa) from men with CBAVD or irreparable obstructive azoospermia, achieved good fertilization and n ormal embryos in 82% of cases, compared to 19% with conventional IVF. There was an overall fertilization rate of 45%, with 85% progressing t o normally cleaving embryos using ICSI, compared to 6.9% using convent ional IVF. The pregnancy rate with ICSI/MESA was 47% per stimulated cy cle (normal delivery rate was 30%), compared to 4.5% with conventional IVF. These results were achieved in patients who had consistently fai led to fertilize in previous cycles with MESA and conventional IVF. We conclude that although complex mechanisms (facilitated by epididymal passage) may be required by spermatozoa for conventional fertilization of human oocytes (whether in vivo or in vitro), no such mechanisms ar e required for fertilization after direct microinjection. Because of t he consistently good results using epididymal spermatozoa with ICSI in comparison to conventional IVF, and also the good results in extreme cases requiring testicular tissue spermatozoa, ICSI may be mandated fo r all future MESA patients with CBAVD, or with irreparable obstructive azoospermia.