Lasers In Medicine

Originally published in Health & Money Magazine

Think of lasers and you probably envision Luke Skywalker dueling the Forces of Evil. But those powerful beams of light are showing up in doctors’ offices and operating rooms where they are being used for things as amazing as any special effect – from improving your looks to mind-boggling techniques for zapping cancerous tumors.

Laser stands for Light Amplification by Stimulated Emission of Radiation. Simply put, it’s a tightly controlled light of a specific wavelength. It can be as benign as the flashy lights at an outdoor laser show or powerful enough to cut through metal. In medicine, it can cut and reshape tissue, weld veins, erase birthmarks and tattoos, or give a high-tech facial.

There are several dozen common uses for lasers in medicine with more ways are invented almost daily. Here are some of the most common and some of the more unusual ways lasers are being used:

VISION TREATMENTS:

Jerry Hirsch was 25 years old when he found he had to wear glasses. “It was traumatic,” he remembers. “Even though I got a really cool pair of glasses, I felt like I was handicapped. I got contacts, but hated the ritual of cleaning them and putting them in.”

The final straw came when he moved and had to get a new driver’s license. “I failed the vision test without my glasses.”

That’s when he opted for laser surgery on his eyes. The thought of someone aiming a beam of intense energy into their eyes or any other body part makes a lot of people squirm, but Jerry says it was quick, painless, and more than successful. “I had significant astigmatism in my left eye and a little in my right. Now my vision is better than 20/20!”

A lot of people echo Jerry’s story. According to medical analysts, more than 1.1 million laser eye surgeries will be performed in the year 2000.

The three main eye abnormalities are: Myopia (nearsightedness – the eye focuses on nearby objects, but things at a distance are blurry), Hyperopia (farsightedness – the eye focuses on things are away, but things close up are blurry), and Atigmatism (objects are blurry at all distances. This can occur with the other conditions). Together, they are called refractive errors.

Two laser treatments correct the conditions. Both of them work by reshaping the cornea, but in different ways.

LASIK (Laser in-Situ Keratomeleusis) is the very latest thing in laser eye surgery. The laser folds back a thin layer of the cornea, then uses the laser to reshape the cornea, improving the way light focuses on the retina. The whole operation takes about 30 minutes, but most of that involves prepping the patient. Actual eye surgery is only a few seconds per eye. It’s done on an outpatient basis, with only eyedrop anesthesia. Many patients see immediate results and most are back on their normal routine the next day.

PKR (Photorefractive Keratectomy) combines computer technology with lasers. Using light pulses that last only a few billionths of a second, the laser disrupts the molecular bonds between the corneal cells by as little as .25 microns. Surgeons say the laser is so precise it could write your name on a strand of hair.

PKR takes about 60 seconds. The patient’s eye is then covered with a bandage contact lens for 1-3 days. Some blurriness is common for as long as a few months, but most people resume normal activities in 2 or 3 days.

Presbyopia is a cousin of farsightedness. It’s what causes people to need reading glasses as they get older. It’s caused by aging instead of a misshapen cornea. Laser treatments for this condition are being tested and will probably be commonly available within a few years.

COSMETIC TREATMENTS
Birthmarks, tattoos, visible veins, wrinkles, and hair removal are all conditions where lasers are used. The results aren’t as universally successful as with eye surgery, though. Skin coloration and location and severity of the condition affect the outcome.

Birthmarks, vascular veins: These can be congenital or be caused by overexposure to the sun, use of oral contraceptives, hormone therapy, or aging. The laser gently seals the blood vessels that are just under the skin, cutting off the flow of blood to the area. Some people say they feel a sensation like the snapping of a rubber band against their skin, but there is rarely any other discomfort.

The results vary. 25% of port wine stains are completely cleared; 75% are significantly or dramatically improved; and 5% do not respond. No one can figure out why. Sometimes, the area gets darker for a few weeks, as though it is bruised, but when that fades, so does the blemish.

Pigmentation and tattoo removal: Pigmentation – brown spots, freckles, and age spots – are caused by deposits of melanin, which gives skin its color. The melanin absorbs the laser’s energy and becomes lighter as it does so. About 80% of the time, only one treatment is needed to get rid of the blemishes.

Tattoo removal works similarly. The tattoo inks absorb the energy and actually dissolve. Don’t expect universal success in removing tattoos though, especially if the design is colorful. Lasers work best on black, blue, and red inks. Lighter colors are less receptive to absorbing the laser energy. While the greens and oranges may fade, they may never completely disappear. Tattoo removal usually takes 3-6 treatments spaced about 1 month apart.

Warts: Lasers successfully remove warts about 2/3rds of the time when conventional treatments don’t work. The energy is absorbed by the blood supply that feeds the wart, and the treated area separates from the skin and sloughs off. Most people need one or two treatments.

Post-surgical scars: Lasers reduce the height and redness of the scars, improve the pliability of the skin and alleviates painful symptoms. The skin improves in appearance and texture in about 1 month. Doctors are the University of Massachusetts are working on ways to use lasers to treat burn scars.

Skin resurfacing: This is the treatment that removes wrinkles, lines, upper lip creases, acne scars, and pox marks. A very high energy level vaporizes the top layer of skin. Examined under a microscope, the “new” skin that replaces the removed layer looks like that of a younger person. The laser also tightens the tissue under the skin, further reducing facial irregularities.

That’s the good news. The bad news is that is it a more complicated procedure. While the patient feels fine, the treatment leaves the skin looking raw and uncomfortable for several weeks, sometimes several months. It can take between two weeks and two months for patients to completely recover.

HAIR REMOVAL:Searching for the perfect bikini line? This might not be the best way to go. Lasers remove hair by shooting energy into the hair follicles, eventually killing them off. The trouble is, the follicles have to be zapped during the hair’s growth period, and each hair seems to have its own growth cycle. In each treatment, only about 20% of the follicles are damaged enough to stop growing, and even then, they seem to rejuvenate and eventually start growing again.

Expect to need 3-5 treatments. Also expect poor results if you have a tan or naturally dark skin. The melanin in the follicles is what absorbs the energy, and darker skin will absorb the energy before or while the follicles are doing so. That means poorer results and can also mean a lightening of the skin around the treated area. Fair skinned people with dark hair see the best results. Mediterranean and African complexions won’t.

HAIR TRANSPLANTS: A few doctors are now using lasers to transplant hair. Lasers drill a hole in the scalp so that individual hairs can be transplanted. It gives a more natural look than hair plugs and is less painful and faster than conventional hair transplant methods.

Tooth Whitening: Lasers whitening removes discoloration and stains from tooth enamel. The laser interacts with a whitening gel to breakup stains in the subsurface portions of the tooth.

SNORING
About 25% of us snore loud enough to wake ourselves or our spouses. Snoring happens when muscles relax during sleep and the soft palate and uvula block airflow. The sound is the vibration of tissues as the air squeezes its way through the throat.

The operation to correct this is called a Uvulopatatopharyngoplasty. (I am not making this up.) It vaporizes the tissues at the back of the throat, so the air can flow freely. It can be done by conventional surgery, but the laser minimizes swelling and the chance of injury to adjacent tissue. It’s done on an outpatient basis under a local anesthetic. Most people have a sore throat for a week or so, but once the swelling goes down, the snoring goes away.

LASER INOVATIONS
As doctors, scientists and engineers explore the way lasers work, they come up with exciting, creative ways to repair injuries, fight chronic diseases, and win a round against cancer.

Laser Welding: This technique uses laser energy to bond two tissue pieces. “Sutureless surgery” is done in two ways. Photothermal welding uses the laser’s heat to activate a kind of biological SuperglueÔ. Photochemical welding uses laser light to activate the biological adhesive.

Transmycordial revascularization (TMR): This gives new hope to cardiovascular patients who have already had bypass operations and angioplasty. It drills holes in the heart muscle, which gets oxygen-rich blood to areas of the heart that were blocked. There’s some sign that this stimulates the growth of new blood vessels.

Only 4300 of the procedure have been performed worldwide, compared to 400,000 bypasses and 500,000 angioplasties. It’s won approval by the FDA, and Medicare began paying for it in July. Many other insurance plans are following suit.

Laser Lumpectomy: Combining high-tech imaging and lasers, doctors are working on a way to destroy cancerous breast tumors without surgery and on an out-patient basis.

Using interactive magnetic resonance (MR), the doctor places a needle in the tumor, then runs a fiber optic wire through it. The wire is used to apply laser heat for about 10 minutes. This heats the tumor and destroys it. Doctors say the MR picture makes it easier for doctors to see all of the tumor and make sure it’s all destroyed, something that isn’t always possible with conventional surgery.

Photodynamic Therapy (PDT): This combines imaging, lasers, and photosensitive drugs to pinpoint and destroy cancerous tumors. A patient takes a light-sensitive drug. After a few days, traces of the drug are found only in cancerous tissues. The drug remains inactive until it is exposed to laser light. Then it creates a toxic form of oxygen that destroys the cancerous cells without damaging the healthy cells surrounding it. This is turning out to be especially effective for lung and esophageal cancers.

Disc Decompression: A ten-year study is underway to monitor patients who’ve had laser surgery to treat bulging discs. Laser energy is applied to the disc via a fiber optic wire. The energy shrinks the disc and pulls the bulge off the nerves. After 7 years, 80% of the followups are successful.

Medical researchers know they’ve barely begun to explore all of the uses of lasers. They’re exploring ways to use them to treat brain tumors, reproductive problems, carpal tunnel syndrome, and oral health. In a few years, using lasers to treat disease will be as commonplace as using a stethoscope to listen to the heart.
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