Rundspermatiden und die klinische Anwendung - Gibt es eine Indikation für die Rundspermatiden-Injektion und die in-vitro-Maturation?

In cases of azoospermia due to different reasons like impaired spermatogenesis or obstruction, spermazoa can be retrieved directly from the testicular tissue and can be injected in the human oocyte using the ICSI-technique (intracytoplasmatic spermatid injection). While fertilisation- and pregnancy rates obtained through the ELSI-technique (elongated sperm injection) show similar good results as the ICSI-technique, results after ROSI (round spermatid injection) show limited success with the spermatid microinjection. The intention of this article is it to present a survey about the problems concerning the clinical approach of round spermatid injection and to reconsiderate critically the need for ROSI in assisted human reproduction today. The main concerns relate to the methodology of separation, identification and isolation of round spermatids. A well experienced laboratory team is mandatory to make the correct recognition of round spermatids from other similar looking round cells within the testicular tissue. Findings of development of an unspecific fertilisation of these round cells appear to be a source of confusion for failed enthusiasm. A failed recognition of the round spermatid stage is also due to a reliable staining technique which is lacking until today. In addition, a good technique for identification of vital cells is not available yet. Concerns about the genetic normality of those early male germ cells with one set of haploid chromosomes are expressed. Up to date there is no way to find out about the genetic condition of those cells. From some authors publicised high rates of fertilisation, implantation and delivery due to round spermatid injection seem not to be relevant from our point of view. This is related to the applied technique of mechanically disintegration and homogenization of the individual testicular tissue samples with following cultivation of whole segments of tissue which makes it nearly impossible to exclude the existance of mature spermatids and even spermatozoa in those samples. Other applied various techniques described by other groups show lowest fertilisation and pregnancy rates. Today the technique of round spermatid injection respectively the injection of cultured round spermatids seems not to be relevant in assisted human reproduction today. Fertilisation- and pregnancy rates are extremely low, existing techniques are not adequate and there is no way to find out about genetic normality of these immature injected male germ cells.