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Injection therapy has many faces

Conway McLean, DPM

You wake up one morning to find that slight twinge in your hip has become significantly painful. You’ve tried icing and ibuprofen but the pain is now severe and demands medical attention. What are you expecting the doctor to do?

As a weekend warrior, you expect some aches and pains following your regular game but that twisted ankle you experienced last weekend continues to hurt with every step. Once again, the typical home treatments, the familiar rest-ice-compression-elevation, have helped, but not enough. Greater expertise is needed.

The arthritic knee, damaged playing college sports, has been bearable for years, but that joint has become progressively more symptomatic over recent months. What are the options? Some pain relief is desired.

These are all common scenarios. A frequent answer to these question is an injection. Many physicians first recommendation for various problems will be an injection. But what exactly is being administered? Most people are aware of a few of the options, yet a plethora of substances can be administered via injection. Injection therapy is a technique practiced for many years and continues to be utilized as a safe, easily performed procedure in an office or out-patient setting.

Specifically, an injection is the act of putting a liquid, especially a drug, into a person’s body using a needle and syringe. This is a technique for delivering drugs without significant quantities of the drug spreading throughout the body. Intra-articular injections, those performed into a joint, have a number of physiologic and practical advantages over systemic medications (such as those taken by mouth), including safety.

Many fear injections. Certainly, the pain produced can occasionally be considerable but, more often, is minimal to mild. Others have allowed hearsay and rumor to rule their decision making, claiming they shouldn’t have any injections because they’re going to do more harm than good. It is true sometimes the relief is temporary, but if you don’t want to have surgery, an injection is an approach for musculoskeletal conditions that should be attempted. It may only give you a few months of pain relief, but it is usually worth trying.

As anyone who has had more than one injection can attest, the symptoms produced by the procedure itself can vary greatly. When larger structures are injected, the procedure tends to be more painful. Yet, there are a variety of methods to reduce the discomfort. As you would expect, technique is a critical factor. Pushing the liquid in faster, although shortening the duration of the process, is more uncomfortable. Thus, patience on the part of the health care provider is beneficial.

Buffering the solution is helpful when the solution is acidic, as is often the case when local anesthetics are used. Understandably, a smaller needle will produce less discomfort, although some medications will not get through certain sized needles. Additionally, the use of an ethyl chloride or “cold” spray numbs the skin for an instant but greatly reduces the initial pain of penetration.

Injection therapy can be used to achieve many different goals, other than just pain relief. The administration of a local anesthetic, a medication which temporarily produces a sensory blockade, can be used for diagnostic purposes. If some particular body part is injected with an anesthetic, and the pain previously experienced is gone while the numbing agent is active, then we can surmise that structure is causing the pain.

Clearly, the benefits of an injection will depend largely on what is injected. Without question, the most commonly utilized medication is some type of corticosteroid, commonly referred to as ‘cortisone’, although that particular medicine is no longer in common use. Corticosteroids are not harmful when used appropriately, and have many different uses. Corticosteroid injections can be therapeutic and diagnostic. They reduce inflammation by inhibiting the production of a number of inflammatory substances. But because they can cause some thinning of tissue, they can be put into a cyst or scar tissue to reduce its mass.

Injections directly into an arthritic joint avoid conventional barriers to joint entry. Intra-articular injections are a minimally invasive procedure and can be performed easily in an outpatient setting, with a short recovery time. Again, there is a drastically lower risk of side effects or systemic toxicity due to this delivery method. Intra-articular corticosteroids are approved by the FDA, although concerns remain regarding the duration of its effects, and their safety profile. And if the situation leading to inflammation is not addressed, predictably, the relief of the steroid injection will be transient.

All medicines have some side effects, including steroids. When used unwisely, what was once a benefit can be a complication. Common side effects are a loss of skin fat, discoloration of the skin, and increased blood sugars. This latter effect is of particular concern in the diabetic population. Uncommon side effects, more likely when used inappropriately, are tendon ruptures or ligament tears.

Patients may be disappointed when they are told the injection recommended may be helpful for only a short time. For each pathology injected, the duration of relief can vary greatly. There are no guarantees with any medical procedure, and this includes injection therapies. The possibility it can provide relief and make some condition better seems a realistic goal, as opposed to trying to give a patient a specific timeline.

Over the last few decades there has been tremendous research into new therapies, with great interest in regenerative medicine. The basic concept is to find healthy ways to improve the body’s healing processes. Some of these newer techniques involve an injection. Some examples include PRP injections (platelet-rich plasma), stem cell therapies, and amniotic membrane injection. Benefits of regenerative medicine techniques include an improved safety profile and, maybe most important, the direct targeting of the biochemistry of osteoarthritis. An increase in movement may be seen, as well as improved muscle strength. They seem to be useful in treating repetitive stress injuries that haven’t healed properly or completely. Maybe most consequential is the reduction of pain levels. The hope is these novel methods may allow some to avoid surgery and can even lead to healing.

One concern with these new technologies is the lack of large scale clinical trials to back up these claims. Long-term clinical studies are needed to increase the evidence available about them, and so earn consideration in treatment frameworks. Until these are performed, there remains an element of uncertainty with these methods.

The regenerative medicine technique in longest use is prolotherapy, in which a highly concentrated glucose solution is injected into a tendon or ligament. This seems to jump-start the healing process, with the resulting inflammation being a natural and integral component of healing, as with platelet rich plasma injection. When performed into a damaged part, these injections can stimulate repair.

Botox injections are a completely different type of injectable therapy. This substance blocks certain chemical signals from nerves, especially those causing muscles to contract. Some common uses are to relax facial muscles (those causing wrinkles) or muscle spasms. Botox injections may also help prevent chronic migraines.

Getting a therapeutic injection can be a scary process and, occasionally, a painful one. Still, there are ways to reduce this. As with any treatment, these methods can be misused. And, once again, there are no guarantees in health care. But the benefits can be significant. Don’t make assumptions: steroids can lead to healing, depending on the situation, and can significantly reduce pain. Don’t let fear rule your decision-making process. Consider carefully all the options your health care team recommends. An injection may be your most effective path to relief.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments atdrcmclean@outlook.com.