Intracytoplasmic sperm injection (ICSI) for severe semen abnormalities: dissecting the tail of spermatozoa at the tip.

Recently, several investigators have emphasized that damaging the membrane of spermatozoa by compressing the mid-piece or cutting the mid-portion of the tail prior to injection yields better results than using motile spermatozoa in intracytoplasmic sperm injection (ICSI). Here we report our experience using a modified immobilization technique of dissecting the tail of the spermatozoon at the tip in 78 cycles on 60 patients. In 55 treatment cycles purely using this modified technique, 468 mature oocytes were injected. A total of 35 oocytes (7.5%) were injured. Of the intact oocytes, 282 (65.1%) were normally fertilized and 266 (94.3%) subsequently cleaved. A single pronucleus was observed in 16 (3.7%) oocytes, and three pronuclei were noted in 11 (2.5%) oocytes. Embryo transfers were performed in 54 cycles, and 18 women (32.7%) achieved clinical pregnancies. In 23 cycles, we compared the effects of these three immobilization techniques on the sibling oocytes obtained from the same patient regarding normal fertilization, abnormal fertilization, and embryo cleavage and quality. The results were comparable among them. Seven pregnancies (30.4%) were achieved in this series. Dissecting a sperm tail at the tip is easily and quickly performed and achieves permanent immobilization. Compression of the mid-piece is also easy, but usually takes several actions to achieve immobilization. Cutting the tail at the mid-portion requires more skill. Therefore, dissecting the tail of the spermatozoon at the tip may provide an alternative method to immobilize the spermatozoon permanently prior to ICSI.