In their Reflection, Tradewell & Masterson comment on the value of FSH and testis volume to predict the chance of sperm retrieval in men with non-obstructive azoospermia, in a series published in the same journal issue by Majzoub et al.  The authors of the Reflection appear to miss the concept that men with obstructive azoospermia can also be identified by the presence of normal FSH and normal testicular volume.  It has been long-ago identified that azoospermic men with a testis length >4.5 cm and FSH <7.6 have a 90% chance of obstructive azoospermia (Schoor et al., 2002).  Since 64% (45/70) of the men who underwent successful TESA had no histologic evaluation, but normal testis volume and normal FSH, the reviewers/Reflectioners seem to miss the obvious conclusion that most of the men with sperm retrieved by TESA likely had obstructive azoospermia rather than non-obstructive azoospermia.  Indeed, of the articles which demonstrate that low FSH and normal testis volume predict sperm retrieval in NOA, most of them have very limited testis sampling and/or include men with obstruction.  Mature series of effective microTESE procedures have demonstrated no adverse predictive value of elevated FSH on sperm retrieval rates (and, indeed, a trend toward lower sperm retrieval in those men with low FSH who are more likely to have diffuse maturation arrest; Ramasamy et al., 2009).

Interpretation of studies that propose preoperative predictive values in men with NOA who undergo attempted sperm retrieval must be carefully reviewed to assess for the extent of sperm search with microTESE as well as the potential contamination of the study population with men who have obstructive azoospermia.  Failure to do so results in pollution of our published literature with misleading information that can ultimately lead to harm to our patients who may be given inaccurate preoperative counseling.

References:

Ramasamy R, Lin K, Gosden LV, Rosenwaks Z, Palermo GD, Schlegel PN.  High serum FSH levels in men with nonobstructive azoospermia does not affect success of microdissection testicular sperm extraction.  Fertil Steril. 2009 Aug;92(2):590-3.

Schoor RA, Elhanbly S, Niederberger CS, Ross LS. The role of testicular biopsy in the modern management of male infertility.  J Urol 2002 Jan;167(1):197-200.