Vasectomy reversal, the operation for reversing a sterilisation operation (a vasectomy) in a man involving removal of the blocked part of each vas deferens, in the upper part of the scrotum, and joining by microsurgery one cut end or the vas to the other cut end. Generally not as successful at returning fertility as the equivalent operation in women (tubal anastomosis): the development of sperm antibodies increases with the length of time since sterilisation and limits the effective sperm count after the reversal. Many clinics now carry out cryostorage of some sperm obtained at vasectomy reversal so that if pregnancy does not happen, or azoospermia persists, in vitro fertilisation (IVF) can be carried out with ICSI without requiring a later operation (for MESA) on the man. MESA with ICSI and IVF can be used as an alternative to vasovasostomy.