Comment on "Sperm Injection at the Para-Polar Body Site in Piezo-Intracytoplasmic Sperm Injection Improves Subsequent...

Piezo-intracytoplasmic sperm injection (piezo-ICSI) is increasingly used to reduce mechanical damage during sperm injection. In the recent study by Ashibe et al., placing the first polar body (PB) at the 2 or 4 o'clock position ("para-PB piezo") improved immediate oocyte survival versus conventional 6/12 o'clock orientation, without negatively affecting blastocyst formation or chromosomal integrity in bovine oocytes. The proposed mechanism is that drilling through the wider perivitelline gap reduces oolemma perturbation and secondary Ca²⁺ influx. We comment herein on: (1) the need for reporting effect sizes with confidence intervals; (2) the imperfect correspondence between PB orientation and spindle location and the value of combining para-PB with spindle imaging; (3) mechanistic studies combining Ca²⁺ imaging, cortical cytoskeleton labeling, and standardized pulse logging; and (4) a recommended path toward human randomized trials with usable-blastocyst yield and euploidy as endpoints. With these refinements, para-PB orientation could be a low-complexity improvement to piezo-ICSI protocols.