Are spermatid injections of any clinical value? ROSNI and ROSI revisited. Round spermatid nucleus injection and round spermatid injection

Abstract

Tiny numbers of spermatozoa can be extracted from an extensive testis biopsy and be used successfully for intracytoplasmic sperm injection (ICSI) in ∼60% of cases of non-obstructive azoospermia caused by testicular failure (e.g. maturation arrest, Sertoli cell only, cryptorchid atrophy, post-chemotherapy, or even Klinefelter's syndrome). However, no sperm are recoverable in 40% of cases even after a very extensive testicular sperm extraction (TESE)-ICSI attempt. Round spermatid nucleus injection (ROSNI) and round spermatid injection (ROSI) would be an appropriate alternative if no elongated spermatozoa, or elongated spermatids were recoverable. Round cells are abundant in morselated testicular tissue of almost all azoospermic men, but difficulties arise in distinguishing under Hoffman or Nomarski optics whether they are haploid round spermatids, diploid spermatocytes or spermatogonia, or even somatic cells like Sertoli cell nuclei or Leydig cells. This paper attempts to clarify such confusion by reviewing data on 143 consecutive testis biopsies of men with non-obstructive azoospermia due to germinal failure, and 62 controls with obstructive azoospermia and normal spermatogenesis. In no cases were round spermatids found in the absence of elongated spermatozoa, and maturation arrest was found always to be a failure of progression beyond meiosis (not at maturation from round spermatid to mature elongated spermatid). Errors arising after injecting somatic or other round cells could result in an appearance resembling fertilization and cleavage, and explain reports of finding 'round spermatids' in azoospermic men where no 'spermatozoa' were retrievable. The use of TESE-ICSI to achieve pregnancies in azoospermic men with deficient spermatogenesis is more concerned with finding tiny foci of spermatozoa, rather than searching for 'round spermatids', which are recoverable only if elongated forms are also available.