If you have ever wished you could leave your body to be fixed and come back to pick it up later, you know just how I felt last spring as I lay, up to my neck in warm water, waiting for more than 1,000 shock waves to pound through my kidney.

I looked up at the life preserver hanging over the bath with a "Swim at Your Own Risk" sign attached. The attempt at humor helped a little.

This was not your everyday bathtub. It had cost Methodist Hospital, Indianapolis, about $2 million and was designed to deliver powerful acoustic shock waves to the "bather" at the rate of about one per second. I hoped that an hour's treatment would pulverize the large stone in my only kidney.

Four months earlier, my urologist, Dr. Virinder Bhardwaj, from the Oak Creek Medical Center in Livonia, Michigan, had shown me the stone on an X-ray. "That kidney is your life-line," he said. "To protect it, the stone has to come out of there. You don't have another kidney to rely on, so we mustn't wait too long."

I had already experienced episodes with high fevers and extreme weakness in the previous weeks and written them off as flu. They had in fact been the result of a kidney infection caused by the stone.

Small tasks were beginning to seem large burdens. Christmas had loomed ahead like a chore instead of a joy.

The doctor told me there were two methods for removing the stone. One was open surgery, during which the stone would be lifted out in one piece. It was major surgery with all its risks and a two-week hospital stay and tedious eight-week recovery. The other possibility was percutaneous removal, in which the stone would be broken by shock waves created by a tube-like device inserted into my kidney through my side.

The latter was less traumatic, but it required probing blindly into the kidney, which could make it bleed. If that happened I would have to have surgery anyway. I knew that occasionally kidneys were damaged and had to be removed in such surgery, and I was born with only one kidney, so there was no back-up should damage occur. The possibility, however remote, of needing dialysis for the rest of my life, or the need for a transplant, was frightening.

The doctor understood my reluctance for such surgery and encouraged me to investigate a method for removing stones that at the time was just being approved by the Food and Drug Administration.

The treatment is called extracorporeal shock wave lithotripsy. Extracorporeal means outside the body, and lithotripsy means stone pulverizing.

The patient is placed in a bathtub-like device and acoustic waves are generated underwater by a "spark plug" electrode. When the electrode ignites, it creats a spark, which vaporizes a small amount of water. The explosion generates a wave of pressure that moves through the water, penetrates the body and smashes into the stone. Wave after wave of pressure from multiple ignitions can pulverize the stone without damaging the surrounding tissue. The gravel resulting from the stone is passed, usually painlessly, in the urine.

The method had been developed in West Germany by Dornier, an aerospace manufacturer, with urologists from the University of Munich. The treatment is to medicine what the Wright brothers' first flight was to aviation, said Dr. Joseph Cerny, chairman of urology at Henry Ford Hospital in Detroit, who gave me a second opinion about my problem and this new approach. "It's the most striking advance in the treatment of kidney stone disease ever, a stupendous advance for the preservation of kidney function."

Unfortunately it is not for everyone. There are height and weight limits and certain medical conditions which would make it unsuitable for some stone sufferers. It has been used successfully, however, on adults as old as 85 and children as young as 3.

Through various tests and X-rays I was found to meet the medical criteria. My health insurance company agreed to meet the costs, estimated at about $4,600. Traditional surgery, with its long hospital stay, would have cost about $6,200. Many insurance companies, however, do not yet automatically pay for lithotripsy treatments.

The waiting list for the treatment was several months, however, and the stone was pretty uncomfortable at times. If it should move or complications arise, I would have to go ahead with surgery, but I decided to try to wait it out.

Often I would wake up at night, conscious of a nagging tender spot in my side. It was like living with a time bomb.

Finally the wait ended and I lay strapped to an operating platform, which had been lowered into the bath with an overhead crane. My arms were strapped alongside my head and my body was numb with anesthesia from my underarms to my toes.

The medical team positioned me so that the energy of the shock waves would be concentrated on the stone. Dr. James Lingeman, a Methodist Hospital urologist, was now in charge of my case.

He instructed me to breathe shallowly and not to speak or move as the shocks were delivered.

By using two X-ray machines pressed against my abdomen, the doctors would monitor the progress of the stone on a television screen.

Suddenly, there was a bright flash under my right side and a loud bang. A shock wave rushed through the water and bashed into my body.

The following shocks came in quick succession, like a jack hammer. The noise was loud and the flashes bright but it didn't hurt. All I could feel was slight sensation in my side like someone flicking me with a rubber band.

From time to time the shocks were stopped and I was repositioned in the bath.

"It's breaking up!" I heard someone say, and tried to relax despite a surge of relief. I tried counting the shocks but Valium had made me light-headed and I could not keep count for long. It was well into the hundreds.

Then it started to get uncomfortable as the anesthetic faded. The shocks gradually started to feel more like a punch in the stomach. Dr. Lingeman, who keep a close watch on me, noticed me wince and the shocks stopped immediately until more anesthetic took effect.

The discomfort was never such that I wished I had asked for a general anesthetic, the more usual procedure. I enjoyed visualizing the stone breaking up more with each shock and felt like an active participant in my return to health. I couldn't help thinking what the alternatives could have been had the stone been found just weeks earlier, before this method became available.

About 45 minutes and 1,000 shocks later, Dr. Lingeman said, "It's all broken up now. Just 200 more for good measure."

The feeling of relief as they came to an end became euphoria. The whole medical team shared my happiness as though they were all enjoying being part of a procedure that is revolutionizing the treatment of one of the most painful diseases known.

I spent most of the next day wandering around the hospital corridors, glass of water in hand, following my instructions to walk and drink as much as possible to help the gravel pass. Other patients were doing the same and we compared notes and marveled at the treatment that had saved us all from surgery.

The only evidence of the shock waves was a few bruises across my back and abdomen, nothing compared with the effects of surgery. The bruises lasted only a few days.

Next morning Dr. Lingeman released me from hospital. I was free to travel back to Northville only 3 1/2 days after checking in. No more antibiotics, no more waking up at night wondering about the tenderness in my side.

After a good night's sleep at home I went to work energetically digging my garden. I had a late start to make up this year. As I worked, I thought of what Dr. Lingeman had said:

"The inventors of the lithotripter deserve the Nobel prize. It was a brilliant idea brilliantly executed . . . It is as easy to use as pushing a button. It is less painful, costs less, shortens the hospital stay and causes fewer complications than other methods."

To me it is a miracle.