בדיקות זרע לפני טיפולי פוריות

Hello,

I have CAVD (congenital bilateral absence of the vas deferens), and have been through a number of failed iCSI treatements with my wife. Our sperm was obtained through PESA – i.e. fine needle aspiration of the epididymis.

We are scheduled to do another treatment shortly, and must go through another sperm aspiration prior to the treatment. We have heard some people suggesting MESA (microsurgical extraction from the epididymis) as opposed to PESA, possibly on halachic grounds. I read Dr. Halperin's articles on "petsua dakka" and "seirus" with interest, and am wondering how these issurim play out in the context of PESA and MESA and biopsy. What is the heter if there is one for doing PESA, MESA, or biopsy when they seem to involve the issur of seirus and potential "petsua dakka" problems, and is there a halachic preference for one technique over the other? I have not succeeded in finding much halachic literature on the topic, perhaps becuase these techniques are so new.

Thank you so much for your help in this issue,