Prolotherapy is an effective, nonsurgical option for wheelchair users with chronic shoulder pain.

By Marc Darrow, MD

Shoulder injuries and wheelchair use appear to go hand-in-hand.

Studies suggest that 50 percent to 90 percent of the approximately 1 million people who use a wheelchair full-time in the United States experience shoulder pain.^1-3 In these cases, prolotherapy is a viable, nonsurgical pain management option for shoulder joint injuries.

Prolotherapy injections of dextrose or sodium morrhuate can rejuvenate tissue. They're often a better option than surgery, which disrupts and removes the tissue. In my clinic, I've achieved an 80 percent to 90 percent efficiency rate treating shoulder and musculoskeletal pain with prolotherapy.

Most of these cases require a series of four to eight injections, delivered one week apart. Some patients with 30 or 40 years of pain have felt better with only one or two injections.

Prolotherapy targets the shoulder tendons and ligaments, helping restore stability during range of motion. With prolotherapy, we can treat the shoulder inflammation conservatively by injecting dextrose or sodium morrhuate into the shoulder joint to help repair and strengthen ligaments and tendons.

Inflammation is the body's attempt to correct injury. Unfortunately, when complete healing doesn't occur, the inflammation cycle never shuts off. This scenario creates a constant low-grade inflammation that causes swelling and pain with or without movement.

Instead of trying to stop the inflammation or curtail it with numerous anti-inflammatory medicines, prolotherapy attempts to gently increase the level of inflammation to a point in which the healing process recurs. A physician creates a localized inflammation to bring immune system cells to the exact spot of an old injury that hasn't healed properly.

The literature backs up the effectiveness of using prolotherapy in healing chronic pain.^4-10 In one study by Liu, researchers injected 5 percent sodium .morrhuate solution into the medial collateral ligaments of rabbits.

After five injections, ligament mass increased 44 percent, thickness jumped 27 percent and the strength of the ligament bone junction improved 28 percent.¹¹

Liu's study confirmed the results of earlier observations by Hackett and colleagues. In that study, researchers spent two years examining the effects of the proliferant Sylnasol when it was injected into rabbit tendons.¹²

In this case, a histological tissue exam revealed an early inflammatory reaction around nerves and blood vessels. The injection also produced lymphocytic infiltration through the area between the two tendons, and the tendons and its sheath. Two weeks after the injection, researchers observed the presence of fibrous tissue and diminished lymphocytic infiltration, which indicated that the proliferation of new white fibrous tissue was still being stimulated.¹²

Prolotherapy addresses the cause of pain and collagen damage. By rebuilding the collagen through increasing inflammation to the area, this treatment strengthens the tendons and ligaments and helps pull the shoulder joint back into place. As a result, we can alleviate chronic pain and joint weakness.¹³

Different prolotherapy injections can produce successful results. Some prolotherapists use mild chemical irritants, such as phenol, guaiacol or tannic acid, to trigger the healing process. These substances attach to cell walls directly where they're injected, which causes irritation that stimulates the body's reactive healing process. Other clinicians prefer to use chemotactic agents—primarily morrhuate sodium, a fatty acid derived from cod liver oil.

The osmotic shock agents in prolotherapy are simple compounds, such as dextrose and glycerine (the most commonly used prolotherapy agents). These agents are safe and water-soluble, and they're excreted from the body after creating the desired effect. They work by causing cells to lose water, which leads to inflammation. It also stimulates the healing response.

Particulates, such as pumice flour, are microscopic particles that attract macrophages, tiny organisms that gobble them up. In turn, they secrete polypetide growth factors that promote collagen production. Most patients need four to six injections, spaced out over several weeks or months, to give collagen fibers time to rebuild and strengthen.

When it comes to the SCI population, prolotherapy can alleviate pain, particularly among wheelchair users who experience chronic shoulder problems. Propelling a manual wheelchair is an intense activity that puts unnatural stress and fatigue on the shoulder joint complex.^14,15

Shoulder joints are an intricate arrangement of muscles and tendons that work together to provide arm range of movement. But this flexibility comes at a cost. To maintain stability, the shoulder relies on muscles and soft, connective tissues of ligaments and tendons.

The rotator cuff—a group of four muscles—.surrounds the top of the humerus and holds the shoulder joint in place. Rotator cuff muscles are responsible for moving the arm in various directions, but these smaller muscles (supraspinatus, infraspinatus, teres minor, subscapularis) are vulnerable to injury. The supraspinatus is the muscle most commonly inflamed or torn, since it's most .susceptible to an overuse injury from the repetitive motion of moving the wheels. But people who use wheelchairs are also at risk for other injuries.

•Shoulder inflammation/tendinitis/bursitis. Shoulder inflammation of the tendons is caused by wear-and-tear over time. It also can occur from an unusual, awkward movement or fall.

Occasionally, excessive use or a shoulder injury leads to inflammation and swelling of the bursa, fluid-filled sacs around joints that lessen friction of shoulder movements. Bursitis is often associated with rotator cuff tendinitis. Symptoms of shoulder bursitis include mild to severe pain, which limits shoulder use. In extreme cases, the joint stiffens and causes adhesive capsulitis, also known as "frozen shoulder."

•Shoulder impingement syndrome. Shoulder impingement syndrome encompasses several problems: inflammation of the bursa located just over the rotator cuff, inflammation of rotator cuff tendons (tendinitis), or calcium deposits in tendons (calcific tendinitis) that are caused by wear-and-tear or injury. In most situations, the acromium or a bone spur put pressure on the supraspinatus tendon.

•Chronic shoulder instability syndrome. Chronic shoulder instability syndrome is caused by trauma from subluxations, dislocations, microtraumas from repetitive tissue strain, or from congenitally loose shoulder joints. Common symptoms include recurrent pain or tenderness in the shoulder joint and arm weakness.

In severe cases, the shoulders pop in and out of joint. Frequent shoulder dislocations stretch the brachial plexus nerves that run from the neck down the arm. As a result, this condition can cause permanent nerve damage and pain, and people may lose the ability to use the arm.

A proper diagnosis of shoulder pain helps determine the main problem and allows you to administer treatment. During a physical examination, screen for physical abnormalities, such as swelling, deformity, muscle weakness and tender areas, and check shoulder range of motion. In addition, observe how far and in which directions a patient can move the arm.

The goal is pain-free movement through complete range of motion. Without achieving that, a patient will only see wheelchair mobility as an exercise in futility.

For a list of references, go to www.rehabilitation-director.advanceweb.com and click on the references tool bar.

Marc Darrow, MD, is an associate clinical professor at the UCLA School of Medicine in California, where he teaches prolotherapy. He's board-certified in physical medicine and is medical director of the Joint Rehabilitation and Sports Medical Center in West Los Angeles. He can be reached at (310) 231-7000 or at www.JointRehab.com