Publications
APS Bulletin • Volume 12, Number 4, July/August 2002
Pain Clinic Perspectives
Steven H. Sanders, PhD, Department Editor
Nerve Block Therapy for Low Back Pain:
Show Me the Money and the Science
Steven H. Sanders, PhD
Given the increasing concerns expressed by many regarding the future of pain specialists (See Loeser, 2001) and the increasing demand for evidence-based practice, it is critical for all of us to take a hard look at those mainstream methods used to treat acute and chronic pain patients. This article highlights the application of lumbar epidural steroid injections and lumbar sympathetic nerve blockade to low back pain. These two procedures are widely used in the treatment of low back pain patients, both at the acute and chronic level, applied in isolation and in conjunction with interdisciplinary pain treatment programs. Several recent practice guidelines have also advocated the use of such block procedures (See ASA, 1997; Stanton-Hicks, et al., 1998).
Let us begin by getting a better sense of the cost of these procedures. We can then examine the evidence for their efficacy.
Show Me the Money
Unfortunately, when trying to determine the cost for lumbar epidural steroid injections or sympathetic blocks, there are no readily available central databases to draw on. (If anyone has such a database, they are urged to share it with our readership). Thus, we are left with attempting to get at least a rough estimate of the cost for these procedures. For the purpose of this article, I will use the 2002 Medicare fee schedule for lumbar epidural steroid injections and sympathetic blockade without fluoroscopy guidance performed in an outpatient hospital setting. The fee for a lumbar epidural steroid injection, including facility charges, is $255.15, and for a lumbar sympathetic block it is $335.84.
Given these costs and making some basic conservative assumptions, we can get a rough estimate of the potential cost of these techniques on an annual basis. Looking at anesthesiologists alone, the American Society of Anesthesiologists states that there are currently more than 37,000 members. For this example, let’s assume that 10% are employing these block procedures on a regular basis. (My guess is that this 10% assumption is quite conservative). If these 3,700 anesthesiologists averaged three lumbar epidural steroid injections and one lumbar sympathetic block per week, at the Medicare rates, this would generate around $203 million per year. Obviously, there are a number of “what ifs” in this example. However, I think most if not all professionals who work in systems that use these block procedures would agree that the current example is indeed a very conservative estimate.
From the preceding limited database and example, I submit that it is quite safe to assume that lumbar epidural steroid injections and sympathetic blockades for low back pain are generating an enormous amount of money for pain specialists and facilities in which they practice. Let us now turn our attention to the scientific evidence for these procedures.
Show Me the Science
One would hope that given the money spent on lumbar epidural steroid injections and sympathetic nerve blocks, there would be strong empirical support for their application. Unfortunately, this is not the case. A review of the empirical literature, including Medline search through July 22, 2002, as well as historical and recent literature reviews (See Boas, 1998; Kores, Sholten, et al., 1995; Nelemans, deBie, deVet, & Sturmans, 2001), resulted in very limited support for either of these techniques. Although there are a number of uncontrolled individual and single group studies employing these two techniques, prospective, randomized, controlled outcome studies with quality measures are rare. None could be found for the use of lumbar sympathetic blocks, with two studies of better scientific quality found for epidural steroid injections. Vijay, Vad, Bhat, Lutz, and Cammisa (2002), used a prospective, controlled study to examine the effectiveness of transforaminal epidural steroid injections on lumbosacral radiculopathy. Using a trigger point injection control group, they found at 1.5 years follow-up that those patients who had received the epidural steroid injections showed a much greater reduction in pain, improvement in function, and satisfaction scores compared to a group that had received trigger point injections. This study suffered from some significant design issues, including a randomization strategy, which allowed the patients to choose which treatment they wished to receive. Also, the control technique used was a poor match for an epidural injection. Likewise, the study used a total of 48 patients, which was rather small to make any generalizations.
A second study by Carette, Leclaire, Marcoux, Morin, Blaise, Saint-Pierre, Truchon, Parent, Levesque, Bergeron, Montminy, and Blanchette (1997), is the best quality science to date. These authors examined some 158 patients diagnosed with herniated disk and lower-extremity sciatica. The patients were randomly assigned to either an epidural steroid injection group or a saline epidural injection group. Pain and functional measures were taken, along with physical examinations at intervals up to three months after the injections. The authors also looked at surgery rates for the two groups 12 months after intervention. Results failed to show any meaningful differences between the groups at 3 months follow-up. The epidural steroid injection group did report some transient reduction in subjective pain intensity and maximum forward flexion, however, this was not sustained at 3 months. The 1-year surgery rate was also almost identical across the two groups.
Carette, et al. did not use radiographically controlled injections, which some critics have suggested may have significantly changed the outcome of the study. Although there has not been a follow-up study using Carette, et al.’s methodology with the addition of fluoroscopy, there is at least one recent study examining the effect of fluoroscopy on improving the accuracy and possible efficacy of an epidural steroid injection. Fredman, Nun, Zohar, Iraqui, Shapiro, Gepstein, and Jedeikin (1999), conducted a prospective study on 50 failed low back surgery patients to examine the accuracy of the air loss of resistance technique in determining penetration of the epidural space, and the actual spread of a contrast medium into the space. They found that the loss of resistance indicator appeared to be a reasonably reliable method to determine epidural space penetration, however, surface anatomy was unreliable with regard to accurate placement of any substance such as steroids. In addition, and most importantly, even with accurate placement, the contrast solution spread to reach the level of pathology in only 26% of the cases. Thus, these findings would suggest that even with fluoroscopy application, improvement in any efficacy of epidural steroid injections is quite questionable.
The current level of evidence for lumbar epidural injections and sympathetic nerve blocks with low back pain appears to be extremely weak. Thus, the scientific efficacy is not present.
Conclusions and Recommendations
From the current review, we must conclude that lumbar epidural steroid injections and sympathetic nerve blocks produce a large amount of money, with very little science to support their application. Does this mean they are useless? Obviously not; these techniques have some value in acute pain management and should not be completely abandoned. However, their use as a mainstream ( almost knee-jerk ) intervention for acute or chronic low back pain does not appear to be at all justifiable at the scientific level.
The fundamental recommendation is quite obvious. Those pain specialists who use these techniques on a regular basis need to support and initiate some clinical research trials that adequately test these procedures’ efficacy. Without this, the routine application of epidural steroid injections and lumbar sympathetic nerve blocks for acute or chronic low back pain is not evidence based. Therefore, when can it be recommended remains an empirical question.
References
ASA, Task Force on Pain Management (1997). Practice guidelines for chronic pain management. Anesthesiology, 86, 995–1004.
Boas, R.A. (1998). Sympathetic nerve blocks: In search of a role. Regional Anesthesia Pain Medicine, 23(3), 292–305.
Carette, S., Leclaire, R., Marcoux, S., et al. (1997). Epidural corticosteroid injections for sciatica due to herniated nucleus pulposus. New England Journal of Medicine, 336, 1634–1640.
Fredman, B., Nun, M.B., Zohar, E., et al. (1999). Epidural steroids for treating “failed back surgery syndrome:” Is fluoroscopy really necessary? Anesthesia, Analg., 88(2), 367–372.
Kores, B., Sholten R., et al. (1995). Efficacy of epidural steroid injections for low back pain and sciatica: Systematic review of randomized clinical trials. Pain, 63, 279–288.
Loeser, J.D. (2001). The future: Will pain be abolished or just pain specialists? APS Bulletin, 11(6), 1–10.
Nelemans, P.J., deBie, R. A., deVet, H.C.W. et al. (2001). Injection therapy for subacute and chronic benign low back pain. Spine, 26, 501–515.
Stanton-Hicks, M., Baron, R., Boas, R., Gordh, T., Harden, N., Hendler, N., Koltzenburg, M., Raj, P., & Wilder, R. (1998). Complex regional pain syndromes: Guidelines for therapy. Clinical Journal of Pain, 2, 155–166.
Vijay, B., Vad, V.B., Bhat, A.L., Lutz, G.E., & Cammisa, F. (2002). Transforaminal epidural steroid injections and lumbosacral radiculopathy. Spine, 27, 11–16.
Editor’s Note: This article is another in a series offering a candid look at treatment interventions used by pain specialists. The intent is to increase dialogue that will enrich our understanding and proper application of these various methods. Your comments, criticisms, and reactions are strongly encouraged.
Steven Sanders is the director of the Siskin Hospital’s Center for Pain Rehabilitation in Chattanooga, TN, and a clinical professor of rehabilitation medicine at the University of Tennessee College of Medicine.