MicroTESE vs. FNA Mapping: Medieval or Modern?
Put two experts in a room and give each of them the same problem to solve. What you’ll find is that they typically use similar
“knowledge structures” and “heuristic strategies” (i.e. organized and principled thinking) and then proceed to break the problem into smaller, more digestible ones to solve it. But, despite similar cognitive approaches, the solutions they derive may be worlds apart. And this is precisely what happened with the problem of male infertility due to azoospermia.
Breaking it Down
Finding sperm in men with no ejaculated sperm due to testis failure is not easy. The first issue is that you need to look in the testicle itself to find sperm. To most men, infertile or not, this alone raises eyebrows. It’s also not a great way to make friends in life. Second, sperm may or may not be there. There may only be sperm precursor cells present, which are not clinically usable. Third, if you rifle around too much or too many times in testicles, they could lose the ability to supply the body with normal testosterone levels, and that’s a whole other problem. Fourth, many patients want to “know before they go” and spend mid-5 figures on assisted reproduction (IVF-ICSI) when they have no sperm available. So, now you see that this seemingly simple problem of no sperm is actually many problems, ranging from medical and physical to financial and psychological.
One of us, the creator of microdissection testicular sperm extraction, hails from New York. Dr. Schlegel observed that if you look closely enough at the 700 ft. of tiny tubules that compromise the human testicle, tubules that contain sperm tend to be larger than those that don’t. So, starting with the testis biopsy, he made the incision much larger, and brought a microscope in to inspect all of the testicular tubules, often for hours. And, lo and behold, more sperm were found in more cases. Not bad, but a bit, well…medieval.
In California, where the sun shines more, we developed a different strategy. Although we agree that sampling intensity is critical to finding sperm, I stepped out of the urology thought-box and considered ways to do this non-surgically, without cutting the testicle. In fact, the inspiration for the approach came from my UCSF colleague Dr. Britt Marie Ljung, a Swedish clinician who told me: “I use fine needle aspiration all the time to diagnose tumors in children’s eyes.” Not sure about you, but to me procedures on eyes and testicles induce a similar gut reaction, so I was convinced this “less is more” approach might be worth investigating. In a series of papers, we described how fine needle aspiration (FNA) is as good as a biopsy for finding sperm and how it allowed for a whole lot more sampling of the testicle. And safely. Further, it delineates who is, and who is not, a candidate for surgical sperm retrieval. Even further, it allows us to “craft” the sperm retrieval to fit the map and reduce the invasiveness, but maintain the success, of sperm retrievals. Now termed FNA “mapping,” or “sperm mapping,” this is a workhorse technique in the field and the ultimate “know before you go” procedure for azoospermia.
Which solution is better? That depends how you define “better.” Higher success? Safer? Cheaper? Fewer complications? The risk/reward combination? Patient-centeredness? This week, these issues will be revealed, in all of their glory, in public debate that we are having at our national fertility meeting. Bring it on, I say.