RESEARCH - Refer to specialist if pain lasts more than three months, expert says

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Refer to specialist if pain lasts more than three months, expert says

Rheumawire

Sep 16, 2005

Gandey

Boston, MA - As newer pain subspecialties crop up, clinicians have more

options than ever for addressing patient pain. Preventing chronic pain

leading to nerve damage and sensitization of the central nervous system is

at the heart of the multifaceted process of relieving patients. " Pain

management is a growing field, " Dr Aneesh Singla (Harvard Medical School and

Massachusetts General Hospital, Boston) told rheumawire, " and it is

important that clinicians be aware of the many options available to them. "

Singla maintains that if pain persists for more than three months, it is

likely time for referral to a pain specialist.

Singla groups pain specialists into four main categories anesthesiology,

neurology, psychiatry, and physiatry and he points to the growing number of

minimally invasive options. Among these is radiofrequency ablation, which

Singla and colleagues believe offers a " new and promising approach for the

treatment of low back pain. "

The researchers make the comment in a letter published in the September 1,

2005 issue of the New England Journal of Medicine [1]. Responding to a

previous article in the journal that questioned the efficacy of the

procedure for low back pain [2], they say that many of the past studies of

this procedure had methodological flaws.

During an interview with rheumawire, Singla noted that, overall, the

evidence for radiofrequency ablation has been conflicting. He cited four key

articles from the literature and noted that two have shown benefit and two

others have not [3,4,5,6]. " Each of these studies had different selection

criteria, however, " Singla said. " I think that once we start implementing

more rigorous and consistent selection criteria, we are going to find that

this is a promising new therapy for select patients. "

Low risk/benefit ratio and low costs

In a lumbar radiofrequency neurotomy, the surgeon places a needlelike tube

called a cannula near the targeted medial branch. A radiofrequency electrode

is inserted down the cannula. The surgeon then sends enough electricity

through the electrode to heat the nerve. The theory is that by stopping the

nerve signals coming from the facet joint, pain in the area stops.

In the original article that prompted the correspondence, Dr Eugene Carragee

(Stanford University School of Medicine, CA) writes, " Radiofrequency

ablation of the small nerves to the facet joints was ineffective in one

randomized trial and showed a moderate effect (6% improvement in disability

scores), which lasted only four weeks, in another. " He continues, " Although

data are insufficient, some authors have suggested a possible benefit of

neuroablation of the facet joint in the extremely small subgroup of patients

with chronic low back pain who respond to placebo-controlled anesthetic

blocks. "

In their letter, Singla and colleagues outline problems with previous

studies, including concerns over selection criteria, which may have

downplayed the efficacy of the therapy in specific subgroups. They write,

" Our opinion of minimally invasive treatment options (injections and

neuroablation procedures) differs from Carragee's. The potential advantages

of these treatments include low risk/benefit ratios and relatively low

costs. "

Responding to the group's letter, Carragee writes, " It is possible that this

screening method resulted in the inclusion of subjects who did not have true

facet-joint pain and thus might account for the lack of efficacy. However,

it may be that the procedure is relatively ineffective even in subjects with

true facet-joint pain. "

Singla and colleagues write, " We fully acknowledge that more clinical

studies are needed to support this new and promising approach for low back

pain. "

Sources

1. Singla AK, Stojanovic M, Barna S. Persistent low back

pain. N Engl J Med 2005; 353:956-957.

2. Carragee EJ. Clinical practice: Persistent low back pain.

N Engl J Med 2005; 352:1891-1898.

3. Van Wijk RM, Geurts JW, Wynne HJ, et al. Radiofrequency

denervation of lumbar facet joints in the treatment of chronic low back

pain: A randomized, double-blind, sham lesion-controlled trial. Clin J Pain

2005; 21:335-344.

4. Leclaire R, Fortin L, Lambert R, et al. Radiofrequency

facet joint denervation in the treatment of low back pain: A

placebo-controlled clinical trial to assess efficacy. Spine 2001;

26:1411-1416.

5. Van Kleef M, Barendse GA, Kessels A, et al. Randomized

trial of radiofrequency lumbar facet denervation for chronic low back pain.

Spine 1999; 24:1937-1942.

6. Gallagher J, di Vadi PP, Wedley JR, et al. Radiofrequency

facet joint denervation in the treatment of low back pain: A prospective

controlled double-blind study to assess its efficacy. Pain Clinic 1994;

7:193-198.

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