CRITERIA FOR CLEARANCE
 

 

Azoospermia or Severe Oligozoospermia?

 
 
A systematic review of the literature (56 studies) published by Griffin et al (J Urol. 2006 Feb;175(2):791-2) found that at 3 months and after 20 ejaculations, more than 80% of patients will be azoospermic. The authors suggested that patients showing severe oligozoospermia could be given clearance.
 
 

A Dutch study (Fertil Steril. 1997 Feb;67(2):332-5) of 395 patients found that 33% had nonmotile sperm present at 12-weeks. Many of these men continued to progress to azoospermia which occurred at a median time of 6.36 months post-vasectomy. The authors concluded that severe oligozoospermia with few nonmotile sperm was a more appropriate criteria for the determination of vasectomy success than azoospermia.

 

 

Another Dutch study published in the British Journal of Urology International by Korthorst et al, studied 1073 men. At 3 months; 51.3% were azoospermic and 44.7% were severely oligospermic (<100,000 nonmotile sperm/mL). These patients were cleared. Follow up at 1 year found no incidence of pregnancy.

 

 

The Spanish study  referenced earlier (Arch Esp Urol. 2007 Jan-Feb;60(1):55-8) found that only 61.9% of men achieved azoospermia by 8 to 12-weeks.

 

 
The Royal College of Obstetrics and Gynaecology (RCOG – U.K.) guidelines supports the use of ‘special clearance’ if there are <10 000 NMS/mL in a fresh specimen provided at least 28 weeks after vasectomy. The rationale for this recommendation was that no pregnancies have been reported in these patients at up to 3 years of follow-up.

 
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