Interventional Therapies in the Continuum of Care
I have been asked to write a regular column on the subject of interventional pain treatment. The editors of Practical Pain Management made this request with the goal of keeping readers as current as possible on the many exciting developments in the field of interventional therapies. The increasing sophistication of the specialty requires greater commitment from all practitioners to be aware of the variety of available treatments to help their patients. My hope is that this column can contribute to that goal.
To understand where we find ourselves with interventional pain treatment today, it is necessary to look back on the specialty’s evolution and how it fits into the larger picture of pain control. In this way, we will see how a reevaluation of pain treatment paradigms may be needed.
Interventional pain therapy began as part of the biomedical model of pain treatment and utilized the belief that pain could be treated adequately with nerve blocks alone. For years, this most common method of chronic pain treatment appeared to help some individuals, however, most patients continued to experience disabling pain. With this as a standard for the biomedical model, it is easy to see how blocks alone would not provide much long-term improvement for most patients. Obviously, broader based solutions were needed.
In the ‘60s, Bonica proposed a multidisciplinary approach whereby specialists from several disciplines contributed to the assessment and management of a patient’s pain. The need to treat pain using a biopsychosocial model gained wide acceptance. This development highlighted the recognition of pain as a frequently complex problem not easily remedied with a “nerve block.” Not surprisingly, this concept was met with resistance from those most equipped to perform blocks.
Today, most physicians who treat chronic pain utilize some combination of the biopsychosocial approach in the belief that maximum improvement for most patients requires consideration of the complex interactions among the biological, psychological, and social aspects of one’s life. This represents an improvement over the attitudes when “nerve blocks” constituted the entire repertoire of interventional treatments. Yet, to support only the biopsychosocial model in treating chronic nonmalignant pain may again oversimplify the broad clinical realities.
Significant advances over the past decade are changing the face of interventional pain management. For many practitioners put off by a formerly simplistic approach, it may be time to take a fresh look. Interventional medicine is an exciting specialty because new technology is introducing more treatment options than ever before. Pain can be treated at its very source and interrupt the pain pathway for extended periods. Some innovations include radiofrequency neurotomies, spinal cord stimulation (SCS), intraspinal delivery systems, and minimally invasive intradiscal therapies. Such therapies can eliminate, or significantly reduce, the pain production or transmission.
In addition to the new technologies, huge progress has been made in the understanding of various pain mechanisms and how to modulate the pain process. Take, for example, the way functional MRI’s demonstrate the physical and chemical neuroadapative changes wrought by prolonged uncontrolled pain on the central nervous system. One of these is central sensitization. In years past, the hyperalgesic state associated with central sensitization was often thought to be a behavioral response to pain rather than a “normal” maladaptive process stemming from the pain itself. Before central sensitization was widely acknowledged, patients who reported experiencing hyperalgesia were treated for pain exaggeration or somatization. Now, using a biomedical model, these patients can be treated with medications to ease the sensitization or, better yet, to try to prevent the sensitization from developing in the first place. Behavioral therapies have also adapted to focus on helping the patient build cognitive skills to lessen the fear and anxiety known to augment pain due to sensitization.
It is appropriate to change the clinical approaches in this way to incorporate new scientific knowledge. In the same way, the advancing technologies of interventional medicine also call for adjustment. This may mean reevaluating the need to psychologically evaluate all patients who experience chronic pain, particularly if such an evaluation means a delay in their pain treatment. The same type of reasoning could be applied to an inflamed appendix. If it is clear from physical and diagnostic exams where the problem lies, then the competent, compassionate response is to remove the appendix. In the same way, if the cause of pain is apparent, the pain pathway clearly observed, and the pain is likely to respond to an intervention, why not proceed to the intervention as a first-line treatment? To do otherwise could cause needless delay and suffering, actually inviting development of the psychosocial difficulties so common to chronic pain.
This suggestion challenges the well-known algorithm for treating cancer pain developed in the ‘70s by the World Health Organization (WHO) (see Figure 1). This three-step “ladder” was soon adopted by the pain community as a systematic approach to treating nonmalignant pain. Its focus on beginning with conservative treatments, then intensifying to more aggressive measures as needed made intuitive sense.
The WHO Three-Step Ladder dictated that a physician administer oral drugs for pain in the following order:
- Non-opioids (aspirin and paracetamol)
- Then, as necessary, mild opioids (codeine)
- Then strong opioids such as morphine, until the patient is free of pain.
Authors who presented at medical meetings commonly added a fourth step to the ladder to include interventional therapy, suggesting it should be only be applied after more conservative approaches had been exhausted.
The WHO ladder was beneficial in establishing the treatment philosophy of trying less aggressive treatments first. This is generally good practice, but I would propose it is not always optimal in every case for every patient. Isn’t it possible that successful first-line interventions could lessen the need for medications, improve quality of life, and lessen the utilization of healthcare resources? Couldn’t function be improved and disability even avoided by using only an interventional therapy? The question is whether or not interventional therapies should always be last on the list of treatment options.
If evidence shows that they should not, it may be time to rethink the WHO ladder.
I suggest, instead, a stratified treatment approach based on the patient’s profile, including history of medical illness, chronicity, severity and source of pain, and available treatment options.