A MODIFIED METHOD OF INTRACYTOPLASMIC SPERM INJECTION WITHOUT THE USEOF POLYVINYLPYRROLIDONE

In a controlled study me compared the outcome of intracytoplasmic sper m injection (ICSI) performed by two different methods. The oocytes fro m 20 patients were equally divided into two groups and injected either by conventional ICSI using polyvinylpyrrolidone (PVP) or by a modifie d PVP-free ICSI procedure. While in the conventional ICSI method the s permatozoon is aspirated into the injection pipette, in the modified I CSI procedure the spermatozoon is attached to the end of the narrow mi cropipette by aspirating its tail. The sperm head is never drawn into the pipette, Accordingly, even a fast-moving spermatozoon can be 'caug ht' easily. As a result of such an aspiration the spermatozoon loses i ts motility. Therefore, PVP is required neither to slow down the movem ent of the spermatozoon nor to facilitate the movement of the solution in the injection pipette, A total of 230 mature oocytes mere injected by both methods and the results were analysed. No differences were ob served in survival rate between the two ICSI procedures (89% and 91%, respectively). However, the proportion of normally fertilized oocytes was significantly higher after microfertilization by modified ICSI (74 %) when compared with the outcome of the conventional ICSI method (62% ). The frequency of abnormal fertilization was not influenced by the m ethod of ICSI used. The cleavage rate and quality of resulting embryos were also comparable. In conclusion, we have demonstrated a modified ICSI method which does not require the use of PVP, When compared with the conventional ICSI procedure, even better fertilization rates can b e achieved. The proposed ICSI modification may provide an alternative procedure for elimination of the potentially harmful effects which may be associated with conventional ICSI.