Computer image sperm selection as a novel approach to subzonal insemination in the human

Utilizing real-time computer image analysis, individual spermatozoa were selected using microaspiration. Selection criteria were based on potential hyperactivation motility characteristics; the amplitude of lateral head displacement > 7.5 microns, curvilinear velocity > 70 microns/s and linearity of < 30%. For this pilot study, 16 patients (eight in each group) were recruited. Using subzonal insemination (SUZI), up to five (mean = 4.4 +/- 0.3) spermatozoa selected using computer-image sperm selection (CISS) were micro-injected, or up to 15 (mean = 12.8 +/- 1.3 SD) unselected spermatozoa. In the group which utilized CISS, 28 out of 49 (57%) oocytes were fertilized compared with 13 out of 52 (25%) utilizing conventional SUZI (P < 0.04); polyspermy was 20% (n = 10) and 2% (n = 1) respectively. CISS with SUZI showed increased efficiency in achieving fertilization and is a novel approach to studying individual sperm function in a sperm egg bioassay where gamete ratios are close to unity.