In a darkened room with a glaring, overhead spotlight, a tiny but intense beam of light is projected into a watery medium. The artist paints the area with the beam of light until the area visibly becomes shorter and tighter. The artist continues working on the masterpiece section by section, until all that remains is a canvas much smaller than before. Imagine the artist as your orthopedic surgeon and the canvas as the interior of your shoulder. Your doctor is performing a laser-assisted capsular shift (LACS) or a thermal capsulorraphy on your unstable shoulder. The use of the thermal properties of lasers in surgical procedures is becoming more common for treatment of joint instabilities. There seems to have been a great speed in introducing this new procedure to heal orthopedic and sports injuries, but there is little peer-reviewed published literature on its efficacy in humans. After investigating this topic, you can decide if the shrink is in, or if the procedure looks all shriveled up.

Shedding Some Light on the Subject
Laser is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. The laser transmits energy in the form of an intense beam of light. The use of light and heat in medicine is not a new concept. The Greeks believed strongly in the healing properties of the sun [1] and fire was used by ancient civilizations to sterilize wounds, control bleeding, and remove unwanted growths [2]. Today, even in physical therapy, electromagnetic energy is used and accepted for heating tissues. Lasers are used in our modern world everyday without problems, and probably without you even knowing it. The bar code scanners at the grocery store and laser pointers are just two examples.
Lasers have the ability to cut, cauterize or coagulate (stop bleeding), or destroy tissue [1, 3]. Of course, tools that perform these tasks are already in use for modern medicine. So why are lasers being touted as the instrument of the future in orthopedic surgeries? Originally, lasers were used to cut tissue. The benefit that lasers have over other proven instruments is that they can shrink tissue using low energy, low level, low intensity, and short treatment times. Lasers are very precise, provide good access to small joint spaces, don’t produce heat or debris, and are minimally invasive. They are introduced into the joint by the use of small arthroscopy holes. The laser used in a majority of research studies is the Holmium:yttrium-aluminum-garnet (Ho:YAG) laser. This laser is considered the state-of-the-art laser for capsular shrinkage. However, most hospitals use radiofrequency laser devices because of the high cost of the Ho:YAG. Thermal shrinkage of collagen has been studied since the 1950s and investigations and clinical usage over the past 5 years have increased dramatically.

How It Works
Remember those summer cookouts when you threw a huge piece of steak on the grill and it shrunk up to a piece not worthy of any self-respecting bodybuilder? Well, laser shrinkage is very similar to outdoor grilling, says Dr. Keith Meister, orthopedic surgeon. He likes to explain the procedure to his patients using that analogy of a common cooking principle.
“It’s like cooking raw steak. You put the meat on the grill and the meat heats up and shrinks. Too much heat and the steak will be burnt.”
The same is true for laser shrinkage surgery. The main ingredient of all ligaments, tendons, and joint capsules is collagen, a strong, fibrous protein that is the most abundant protein in the body. It is a well-known phenomenon that collagenous tissue, like skin, shrinks when it is heated [4]. With the use of lasers, tissue absorbs the laser light energy and then transforms the light energy into thermal energy, which raises the tissue temperature [3]. This then leads to the tissue shrinkage. There is some initial thermal damage to the tissue, but this tissue heals and repairs itself [5]. According to a manufacturer of laser equipment and several studies, the contraction of the collagen molecule is both time and temperature dependent. This means that there is an optimal temperature and certain amount of time for the tissue shrinkage to occur. Any alterations can produce significant tissue damage or no changes at all [6].

Shoulder Shrinkage
Shoulder instability is a common and frequent problem in many athletes, particularly with swimmers and overhead and throwing athletes. Some athletes may be born with lax ligaments and some acquire laxity through their aggressive sporting activities. Shoulder instabilities are first treated conservatively with physical therapy that focuses on rotator cuff and scapular stabilizer strength. In extreme cases or with highly competitive and professional athletes, conservative muscle strengthening may not be enough. Arthroscopy to repair shoulder instabilities is limited because the arthroscope can’t get to the entire structure and high recurrency rates have been reported. The open surgical procedures are difficult, the rehab painful and lengthy, and sometimes leads to loss of function. But the laser is coming to the rescue, or so proponents assert. The laser-assisted capsular shift (LACS) and laser capsulorraphy describe the use of laser energy to shrink the shoulder capsule and tighten up the ligaments and other tissue that becomes loose. The original studies that gave physicians the green light for the capsular shrinkage procedure came from the success of laser shrinkage on rabbits’ knee joint capsules [5]. Although the author of this study cautioned the interpretation until more studies were done, especially on humans, the procedure took off.
“I think this is an exciting technology that adds a new dimension to arthroscopic surgery,” says Dr. Richard Simon, orthopedic surgeon. “Lasers are not only being used in shoulders, but also show promise in knees and ankles.”
Jane Jarosz-Hlis, PT, CSCS finds laser-assisted shoulder surgeries beneficial to the patient’s rehabilitation. “Although the first six weeks of therapy are less aggressive than the typical open procedure therapy, progress after that protective phase is rapid. I even see patients finish their rehab faster than the patients who were opened up.

To Shrink or Not to Shrink
The FDA approves the use of lasers for arthroscopic surgery. Surgeons must attend a course that teaches the basic science, safety, and clinical applications of the laser, and hospitals require this educational certification. Low power lasers don’t produce significant heat or debris, so safety is limited only to eyewear [1]. All complications reported were due to the improper use of the laser [7]. The possibility exists for an unskilled surgeon to apply too much time and temperature and therefore burn and destroy tissue. In addition, the Ho: YAG has no specific feedback mechanism that enables a surgeon to identify the amount of heat exposure and temperature within the tissue [3]. The amount of energy emitted at the laser tip is measured, but not the energy absorbed by the tissue. Therefore the surgeon has to visibly watch the shrinkage and stop when they feel the capsule is tight enough. Unfortunately, most of the research studies were performed on animals and in vitro (outside the body). So far there have not been any long term studies. However, because this is such a new procedure, the long-term studies will start with the patients who receive this surgery now. Many studies were poorly designed without control groups and comparable standard orthopedic operative groups. Surgeons even started performing this procedure before concrete evidence was shown. Indeed, the lack of basic science studies and the aversion of many doctors to the marketing aspects of laser technology have undermined its widespread acceptance [3].

Shrink-Wrap it Up
Because of the lack of long term studies and the fact that most of the research is based on animal models and case reports, you should think of this surgery as experimental and investigative – researchers don’t even know yet if the shrinkage is permanent. Lasers may turn out to be very effective tools in the surgical suite of the future not just for shoulder capsule shrinkage, but for knees and ankles as well. In addition, many of the other properties of lasers are being utilized to treat pain, inflammation, and arthritis. Science will continue to light up this controversial topic with more research, and we will wait for enlightenment.

References
1. Basford, J.R., Laser therapy: scientific basis and clinical role. Orthopedics, 1993. 16(5): p. 541-547.
2. Thabit, G., III, Therapeutic Heat: A Historical Perspective. Operative Techniques in Sports Medicine, 1998. 6(3): p. 118-119.
3. Nottage, W.M., Laser-assisted shoulder surgery. Arthroscopy, 1997. 13(5): p. 635-638.
4. Hayashi, K. and M.D. Markel, Thermal Modification of Joint Capsule and Ligamentous Tissues. Operative Techniques in Sports Medicine, 1998. 6(3): p. 120-125.
5. Hayashi, K., et al., The effect of nonablative laser energy on joint capsular properties. An in vitro mechanical study using a rabbit model. Am J Sports Med, 1995. 23(4): p. 482-487.
6. Hayashi, K., et al., The effect of thermal heating on the length and histologic properties of the glenohumeral joint capsule. Am J Sports Med, 1997. 25(1): p. 107-112.
7. Brillhart, A., Complications of Thermal Energy. Operative Techniques in Sports Medicine, 1998. 6(3): p. 182-184.