May 26, 2019

Kidney stone no match for `Emmy’

Four months ago, around Thanksgiving, I wrote a column describing what I thought was the successful treatment of my kidney stone with a new device called an Extra-Corporeal Shock Wave Lithotriptor. This device generates ultrasonic pulsations (the shock wave) outside the body (extra-corporeal) and focuses them on a kidney stone inside the body. The shock waves pummel the stone repeatedly, eventually disintegrating it into tiny grains that can he easily passed in the urine, so when tiny grains of stone began appearing in my urine that night, I was sure we’d gotten the little bugger.

My urologist friend wasn’t so sure. He’d watched the stone being pounded by the shock waves but he hadn’t seen it shatter as it should have. A week later X-rays showed the stone was still there, battered but unbroken. My column had been premature.

That led to another session with the extra-corporeal lithotriptor (unsuccessful), then an attempt to remove the stone through a cystoscope (equally unsuccessful). The Bangor urologist then suggested I see a friend of his in Boston, one who had gained fame in urological circles five or six years earlier by inventing an intra-corporeal laser lithotriptor.

Thus it was that I arrived at the office of the Boston urologist my friend had recommended, Dr. Stephen Dretler, head of the Lithotriptor Unit at Mass General.

In 30 seconds I knew my friend had done well by me. What gets to you with Dr. Dretler is his enthusiasm. As he began describing to me not his laser lithotriptor but his new electro-mechanical impacter, his eyes were dancing.

It turns out this extra-corporeal lithotriptor that had been used on me sometimes ran into stones that were just too hard for it to crack. Laser beam devices had been tried but they had generated too much heat at the stone or had otherwise damaged surrounding tissues. Dr. Detler and his team had, however, by refining the laser, been able to develop a beam of exactly the right wavelength that did shatter stones without damage to surrounding tissues. And yes, that was available and he was sure it would work. But what he wanted to talk to me about now was his new device.

When the original laser lithotriptor was perfected he was shocked to find each unit, with its sophisticated electronic, computerized controls was going to cost in the neighhorhood of a quarter of a million dollars to produce. To some researchers, this might have been acceptable, but not to Dr. Dretler. He wanted a device that all hospitals could afford, not just the big centers like Mass General but also the smaller places like Eastern Maine Medical Center. He sat down with representatives of a company called Physical Science and said something like, “Let’s go back to square one. Surely we ought to be able to figure out a way to break up kidney stones with a machine a lot less expensive than that.”

Well, they succeeded. What they’ve come up with is nothing more nor less than a mini-mini-miniaturized version of a trip hammer, a pneumatic drill, those things they use to break up pavement on city streets when you’re trying to sleep. A tiny little head, made of super tough metal, projects a fraction of a millimeter beyond the sheath that holds it. There is some sort of electro-mechanical means to draw the head back and shoot it out again with great force, then pull it back and fire it again and again and again, five or six times a second. Now can you see the similarity to a pneumatic drill? This whole thing has to fit on the end of a flexible tube no wider than a piece of spaghetti.

This new device is called an electro-mechanical impacter, or EMI. The office staff refers to it affectionately as “Emmy.” For the moment, the only place it’s licensed to be used is at Mass General. They are in the tedious process of seeking FDA approval for it as a new medical device. They’ve already gone through the first two phases of that process and are now in the third and last phase. At this stage they have to build up a series of cases to prove that it does work and that it is safe. I am no. 33 in that series.

The procedure itself wasn’t much. I went into an ambulatory care center operating room at 9:45 a.m., Dr. Dretler said hello, the anesthetist told me to take a deep breath, and I was gone. There was no incision. With the patient anesthetized, the urologist forces a fair-sized metal tube, a cystoscope, into the bladder through the urethra. (The urethra is the tube that leads from your bladder to the outside.) Once the cystoscope is in the bladder, the urologist opens the end to reveal a marvelous array of lights, mirrors, instruments and irrigation tubes, all controllable from the outside. Dr. Dretler threaded an instrument up my left ureter, latched onto the stone, then sent the EMI up beside it and began hammering away. The stone was no match for “Little Emmy.”

The best I’ve saved for last. Remember Dr. Dretler’s goal was to devise a machine just as good as or better than the laser lithotriptor but without that astronomical price tag of $250,000. Little Emmy’s cost is going to be something less than $10,000, and she hasn’t failed in her first 33 outings.

The world of medical research needs a lot more people with Dr. Dretler’s concern for costs. I don’t expect anyone will ever come up with a Magnetic Resonance Imager that will cost less than a million dollars, but all doctors know there are lots of other medical gadgets out there that are vastly overpriced. That’s one thing we should be taking a hard look at as we try to trim medical costs.

Robert A. Graves, M.D. is a retired physician who lives in Orono. His column appears biweekly.

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