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MAY / JUNE 2013 :: 74(3)
Chronic Pain

This issue focuses on the challenge of managing chronic pain. Commentaries present various treatment options, including opioids, nonopioid medications, surgery, and alternative therapies. Authors also address the problems of opioid misuse and abuse and discuss ways to lessen these risks. Original articles examine health professionals’ communication with adolescents about smoking, as well as children's immunization status as verified by practice records and by the North Carolina Immunization Registry.

INVITED COMMENTARY

The Needle in a Haystack: Appropriate Use of Interventional Techniques in the Management of Chronic Pain

William S. Blau

N C Med J. 2013;74(3):215-217.PDF | TABLE OF CONTENTS



Management of chronic pain is often difficult. Interventional approaches, such as joint injections and nerve blocks, can reduce dependence on opioid therapy, polypharmacy, and long-term costs; they can also dramatically improve pain control and function. However, interventional techniques must be used ethically and judiciously as part of a comprehensive approach to patient-centered care.

Chronic pain is a complex disorder that manifests in a variety of ways. In extreme cases, some patients may perceive chronic pain to be worse than death. In addition to the direct suffering induced by unrelenting pain, which in many cases occurs in the absence of a specific diagnosable etiology, a patient with chronic pain may experience sleep disturbance, depression, anxiety, or impairment in physical, cognitive, and psychosocial functioning. Many cases present challenging ethical and medical issues regarding the management of controlled substances. Addressing the needs of these patients requires an interdisciplinary approach, along with considerable time, effort, and patience.

Chronic pain is best understood as a chronic disease, and the most appropriate approach to the care of patients with chronic pain draws from the model of chronic disease management [1]. However, comprehensive and integrated treatment—which includes functional rehabilitation, psychological approaches (such as cognitive behavioral therapies), and analgesic management—is expensive [2]. Such treatment requires a considerable amount of time and effort on the part of both patients and their providers, and it may not lead to long-term efficacy for many patients, especially those with comorbid psychological or psychiatric disorders. When all else fails, some patients can benefit from carefully managed and monitored opioid therapy. However, use of opioid therapy for chronic pain is increasingly controversial due to the relative lack of data on long-term efficacy; the preponderance of side effects; and the risks of drug abuse and diversion, which affect patients and society. Furthermore, management of long-term opioid therapy can be burdensome for the provider and is not very well compensated compared to interventional therapies.

Relatively few medical therapies for chronic pain have a strong base of supporting evidence. For even the best pharmacological therapies, the number needed to treat (NNT)—the number of people who need to be treated for 1 person to benefit—is typically in the range of 3–4. Most interventional therapies are supported by weak evidence, at best [3, 4]. Nonetheless, providers have an ethical mandate to control pain, and patients with chronic pain demand treatment more vigorously than do patients with most other problems. For example, these patients may say, “If I can’t get rid of this pain, I don’t know what I’ll do,” or “Somebody has to do something; I can’t live like this.” When was the last time a patient with essential hypertension threatened to commit suicide if his or her physician did not promptly offer an effective treatment? Patients with unrelenting pain can become desperate, and their providers often feel frustrated [5].

Benefits
Interventional pain management, which includes the use of invasive techniques such as joint injections and nerve blocks, may be an imperfect approach to the treatment of chronic pain, but it may still be preferable to more comprehensive methods in some cases. By definition, chronic pain has no cure, but therapies that hold the potential to dramatically reduce, if not cure, the biological source of the pain are tempting. Indeed, evidence shows that, in the relatively rare instances when pain can be eliminated, many of the patient’s functional and psychosocial comorbidities also improve [6]. When interventional therapies work well, they can reduce polypharmacy, dependence on opioid therapy, and long-term costs, and they can dramatically improve pain control and function [7].

Unfortunately, there is a dearth of high-quality studies validating many interventional therapies. Empirically, individual patients appear to respond well to these treatments—bearing in mind that the outcome being sought is not a permanent cure, but rather an improvement in pain, physical and emotional functionality, and overall quality of life that lasts for at least several weeks. For patients whose lives have been decimated by intractable pain and whose only other option may be lifelong dependence on opioid analgesics, even a modest chance of success from a procedural intervention may be acceptable to the patient and the provider.

Use of interventional therapies is limited by clinicians’ inability to predict which patients will respond positively to these approaches. Currently, the only way to really know who will respond to an epidural or transforaminal steroid injection is to offer the procedure as a trial. Many patients will benefit from this treatment, even for generally unsupported indications such as axial lower back pain [8], but many other patients will not receive sufficient benefit and yet will incur the cost and risks of the procedure. For potentially effective interventions, such as medial branch neurotomy for treatment of facet or sacroiliac joint pain [9], patients can be screened with temporary anesthetic blocks; from a health care perspective, however, even this empirical approach may not be the most cost-effective course [10]. Another challenge is the temptation to repeat costly procedures that provide only limited benefit. Some patients find real value from an intervention that may provide only hours or days of relief, yet repetition of such procedures is not a viable strategy for long-term management.

Interventions that can be effective and that pose minimal risk include trigger-point injections, which are best used in support of physical therapy; epidural or transforaminal steroid injections; cervical or lumbar facet blocks; radiofrequency neurotomy of the facet joint; sacroiliac joint injections; radiofrequency neurotomy of the sacroiliac joint; bursa injections; neurolysis of the peripheral nerve, plexus, or ganglion (especially in the setting of terminal cancer-related pain); vertebroplasty or kyphoplasty; implantation of a spinal cord stimulator; and implantation of an intrathecal infusion pump. The most expensive therapies—those that involve implantation of a spinal cord stimulator or an intrathecal drug infusion pump—do have the potential to produce dramatic, enduring, and cost-effective improvement in pain and function over the long term, but they are not effective for all types of pain and are not appropriate for all patients [11, 12]. Nevertheless, with careful patient selection and appropriate psychological and therapeutic screening (via a temporary trial of the proposed therapy), interventional therapies can produce excellent long-term outcomes for patients in whom all other analgesic strategies have failed [13, 14].

Other procedures that may have value in some patients include peripheral nerve blocks and sympathetic nerve blocks. Procedures with questionable value include pulsed radiofrequency procedures (nondestructive), discography, intradiscal electrothermal therapy (IDET), epidural neurolysis (Racz procedure), and epiduroscopy [15-17].

Risks and Adverse Effects
Utilization of interventional approaches for the management of chronic pain carries risks of procedure-related complications. The most concerning complications generally involve uncontrolled bleeding or infection (eg, epidural abscess or hematoma), but these risks are acceptably small with proper patient selection and sterile technique [18]. Nevertheless, the consequences for individual patients who experience such complications can be devastating. For example, a recent outbreak of fungal meningitis associated with the use of tainted compounded steroid preparations has resulted in 741 cases of clinical infection, associated with 55 deaths, in 20 states [19]. Likewise, cervical transforaminal steroid injections were widely used to treat radicular symptoms until several years ago, when it became apparent that rare catastrophic complications were occurring, likely due to embolization of the cervical spinal cord by undetected intra-arterial injection of particulate steroid suspensions [20]. Although such occurrences are extremely rare, the decision to pursue any interventional procedure for the management of chronic pain must incorporate a realistic assessment of risk versus benefit.

Appropriate Use
Interventional approaches also carry disadvantages from a strategic standpoint. Although these therapies can yield significant long-term benefits, there are increased upfront costs, especially with regard to trials of therapy that may or may not ultimately prove to benefit the patient [11, 12]. The appeal of an approach that provides profound, if only short-term, pain relief may result in patients depending on medical procedures to control their pain, rather than learning skills to manage and cope with their pain. Similarly, physicians may be tempted to over-rely on interventions for various reasons. Administering interventions is more enjoyable than managing long-term opioid therapy, and providers are well reimbursed for interventional approaches under a fee-for-service health care system. This temptation may be reinforced when physicians feel the need to offer something for problems that otherwise seem to have no solution. Patients with chronic pain often hope for a cure that does not exist, and they are thus particularly vulnerable to practitioners who offer the semblance of a cure or a dramatic improvement through interventional means.

Of greater concern are providers who choose to limit their practice in order to avoid the challenge and responsibility of comprehensive pain care while emphasizing the use of interventional approaches. Financial incentives in medicine are not always aligned to reward the most patient-centered care, which has had unfortunate consequences for the treatment of chronic pain, as pharmacologic management is often inadequately reimbursed. In contrast, pain procedures are often well compensated, regardless of their ultimate efficacy. Some providers define themselves as “interventional pain physicians,” but I would suggest that the real question is whether or not a physician is a pain medicine specialist, and I would hope that all pain medicine specialists would have the knowledge and skills to incorporate the benefits of interventional therapies into a comprehensive program of patient-centered care [21].

Finally, the relative ineffectiveness of current treatments for chronic pain provides a strong motivation for adopting new approaches that hold the promise of better outcomes, even if many of them are interventional and untested. Curiously, many of these treatments first take hold in the realm of private practice before being subjected to more rigorous examination from an academic perspective. In 1997, a new form of internal disc disruption was introduced as a treatment for discogenic pain, which is one of the most common sources of chronic back pain. This procedure, IDET, involves threading a wire into the posterior annulus of the disc and heating the disc contents. This technique and others similar to it were readily incorporated into the interventional pain armamentarium. Fifteen years later, however, in the absence of convincing evidence of the procedure’s safety and efficacy, IDET is now rarely if ever offered, and most third-party payers consider it to be experimental.

Conclusion
Chronic pain is a devastating disease. Despite increased clinical and experimental attention to this disorder over the past few decades, clinicians still lack reliably safe and effective medical treatments. Patients who suffer from chronic pain are best served by a comprehensive and integrated care model that not only provides the best pain relief possible but also offers treatments that optimize function and improve patients’ ability to cope with pain. Interventional techniques do not take the place of, nor do they eliminate the need for, a comprehensive approach, but they can be valuable adjuncts when used judiciously as part of a patient-centered program [22].

Acknowledgments
Dr. Richard Boortz-Marx provided helpful comments on a draft of this commentary.

Potential conflicts of interest. W.S.B. has no relevant conflicts of interest.

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William S. Blau, MD, PhD professor, Department of Anesthesiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Address correspondence to Dr. William S. Blau, Department of Anesthesiology, N2201 UNC Hospitals, CB #7010, Chapel Hill, NC 27599 (wblau@aims.unc.edu).