We all know that urban legends are built from far less copious and visible citations than the two just cited. And so once again, your loyal scribe has attempted to lance a boil built upon logic and evidence that can be called into question. It would be best to start with a logical sinkhole.
The concept of a disk rupturing during manipulation may have had its origins with the assertion made by Farfan over 34 years ago to the effect that rotational stress causes disk failure. This study demonstrated that in rotation, normal disks withstand an average of 23 degrees and degenerated disks an average of 14 degrees before failure erupted.3 However, posterior facet joints limit rotation to a maximum of 2-3 degrees and would have to fracture to allow any further rotation to occur.4 Any disk failures produced experimentally by torsion are caused by peripheral tears in the annulus, rather than prolapse or herniation,4 so one can readily see that there appears to be a (pro)lapse of logic in this argument.
It's the evidence that should connect the dots here, however. In an outstanding systematic review and risk assessment,5 Oliphant demonstrates that, compared to accepted medical treatments for lumbar disk herniation (LDH), spinal manipulation emerges as an attractive alternative. Citing the risk estimates of LDH from 19 references, Oliphant calculates the net risk of a clinically worsened disk herniation or cauda equina syndrome from 6245 million patients studied over a 40-year period who present with LDH to be less than one in 3.7 million excluding anesthesia (1.8 million including anesthesia).5
Taking this number and running comparisons to other modalities, you have to like the odds for spinal manipulation:
- If significant complications occur in 1%-4% of NSAID users,6 spinal manipulation is between 37,000 and 148,000 times safer.5
- If significant complications occur in 1.5%-12% percent of LDH surgeries,7-9 spinal manipulation is between 55,000 and 444,000 times safer.5
- If cauda equina syndrome [CES] occurs in the aforementioned one per 3.7 million manipulations5 and in 0.2%-1% percent of surgeries,10,11 spinal manipulation is at least 7,400 to 37,000 times less likely to yield CES.5
It turns out that more than one-third of the total health care and societal costs may be attributed to just 1 percent to 2 percent of low back pain patients who undergo surgery for disk herniation. The problems here are that: [I] the evidence for most surgical procedures is unclear;12 [II] this surgery has not been shown to be more effective than conservative care;13 and [III] this surgery has a complication rate of 24 percent, almost half of which are major complications.7 A separate report indicates that, in patients with lumbar disc herniations, the recurrence of back pain occurs with equal frequency in patients treated either with surgery or by conservative means. The recommendation therefore is made that conservative therapy, rather than surgery, should be the first option of treatment.14 Compared to other modalities, you therefore begin to suspect that perhaps spinal manipulation has, in the words of the classic short story writer Damon Runyon, "been slipped a rubber peach."
Let us look at the actual outcome studies themselves. Two randomized trials currently support the wisdom of considering spinal manipulation as a treatment option for this condition. One study involving 51 cases of myelographically confirmed disk herniation compared rotational mobilization to conventional physical therapy (e.g., diathermy, exercise and postural education). The manipulation group demonstrated greater improvement in range of motion and straight leg raising compared to the physical therapy cohort, leading Nwuga to conclude that manipulation was superior to conventional treatment.15
The second trial examined 40 patients with unremitting sciatica diagnosed due to lumbar disk herniation with no clinical indication for surgical intervention. Subjects were randomized into two treatments: chemonucleolysis (chymopapain injection under general anesthesia) and manipulation (15-minute treatments over 12 weeks, including soft-tissue stretching, low-amplitude passive maneuvers of the lumbar spine and the judicious use of side-posture manipulations). Back pain and disability were appreciably lower in the manipulated group at 2 and 6 weeks, with no improvement or deterioration in the chemonucleolytic group. By 12 months, there were improvements in both groups with a tendency toward superiority in the manipulated cohort. Costs of treatment in the manipulated group were less than 30 percent encountered by the injected patients; furthermore, the latter group averaged expenditures of £300 (approximately $540 U.S.) for treatment failures, with no such costs experienced by the manipulated population. Thus, in terms of outcomes, absence of side-effects, and cost in treating herniations, spinal manipulation appears to have scored a trifecta victory.16
Additional support for manipulation in the treatment of disk herniations is provided from several prospective studies.17-21 The largest involved 517 patients diagnosed with lumbar disc protrusion, 77 percent of these having favorable response from pain after manipulative therapy.20 A literature review from Cassidy22 suggests that an additional 14 of 15 patients with lumbar disc herniations experienced significant relief from pain and clinical improvement after a two-to-three week course of side-posture manipulation.
Taking all of these viewpoints into account, I began asking what universe we are in, and quickly drafted a letter to the Merck Manual to challenge the quotation at the beginning of this article. A reply from editor Mark Beers, dated July 27, happily pointed out that "the statement you objected to is no longer present." He thanked me for my "interest in improving the quality of The Merck Manual." This particular episode may come to a Hollywood ending for now, telling us that being armed with the proper research evidence and using it judiciously is a necessary, but not always sufficient, first step to address these grievances. This is precisely where the Foundation for Chiropractic Education comes in with its concern for developing and applying research evidence to correctly document chiropractic health care. Unfortunately, as we all know only too well, there are a multitude of other dragons to slay. The support of FCER by the chiropractic community and any patients concerned with proper health care is absolutely essential for this effort to continue.
- Jagbandhansingh MP. Most common causes of chiropractic malpractice lawsuits. Journal of Manipulative and Physiological Therapeutics 1997;20:60-64.
- The Merck Manual, 17th edition. Rahway, NJ: Merck & Co., Inc., section 5, chapter 59.
- Farfan HF, Cossette JW, Robertson GH, Wells, RV, Kraus H. The effects of torsion on the lumbar intervertebral joints: the role of torsion in the production of disc degeneration. Journal of Bone and Joint Surgery Am 1970;52(3):468-497.
- Adams MA, Hutton WC. Mechanics of the intervertebral disc. In: Ghosh P (ed.) The Biology of the Intervertebral Disc, Volume II. Boca Raton, FL: Raven Press, 1988, pp. 39-71.
- Oliphant D. Safety of spinal manipulation in the treatment of lumbar disk herniations: a systematic review and risk assessment. Journal of Manipulative and Physiological Therapeutics 2004;27(3):197-210.
- Bjorkman DJ. Current status of nonsteroidal anti-inflammatory drug [NSAID] use in the United States: risk factors and frequency of complications. American Journal of Medicine 1999;107:3S-8S.
- Fritzell P, Hagg O, Wessbeg P, Nordwall A. Swedish Lumbar Spine Study Group. A multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine 2001;26:2521-2534.
- Kardaun JW, White LR, Schaffer WO. Acute complications in patients with surgical treatment of lumbar disectomy. Journal of Spinal Disorders 1990;3:30-38.
- Elias WG, Simmons NE, Kaptain GJ, Chadduck JB, Whitehill R. Complications of posterior lumbar interbody fusion when using a titanium treated cage device. Journal of Neurosurgery 2000; 93: 45-52.
- Henriques T, Olerud C, Petrin-Mallmin M, Ahl T. Cauda equina syndrome as a post-operative complication in patients operated for in lumbar disc herniation. Spine 2001; 26: 293-297.
- McLaren AC, Bailey SI. Cauda equina syndrome: A complication of lumbar disectomy. Clinical Orthopedics 1986;204:143-149.
- Gibson JNA, Grant I, Waddell G. The Cochrane review of surgery for lumbar disc prolapse and degenerative lumbar spondylosis. Spine 1999;24:1820-1832.
- Saal J. Natural history and nonoperative treatment of lumbar disc herniation. Spine 1996;21:2S-9S.
- Postacchini F. Spine update: Results of surgery compared with conservative management for lumbar disc herniations. Spine 1996;21(11): 1383-1387.
- Nwuga VCB. Relative therapeutic efficacy of vertebral manipulation and conventional treatment in back pain management. American Journal of Physical Medicine 1982;61(6):273-278.
- Burton AK, Tillotson KM, Cleary J. Single-blind randomised controlled trial of chemonucleolysis and manipulation in the treatment of symptomatic lumbar disc herniation. European Spine Journal 2000;9:202- 207.
- Henderson RS. The treatment of lumbar disk intervertebral disk protrusion: an assessment of conservative measures. British Medical Journal 1952;2:597-598.
- Mensor MC. Non-operative treatment, including manipulation, for lumbar intervertebral disc syndrome. Journal of Bone and Joint Surgery 1955;37A:925-936.
- Chrisman OD. A study of the results following rotary manipulation in the lumbar intervertebral disc syndrome. Journal of Bone and Joint Surgery 1964;46A:517-524.
- Kuo PP-F, Loh Z-C. Treatment of lumbar intervertebral disc protrusions by manipulation. Clinical Orthopedics 1987;215:47-55.
- d'Ornano J, Conrozier T, et al. Effets des manipulations vertebrales sur la hernie discale lombaire. Review of Medical Orthopedics 1990;19:21-25.
- Cassidy JD, Thiel HW, Kirkaldy-Willis KW. Side posture manipulation for lumbar disc herniation. Journal of Manipulative and Physiological Therapeutics 1993;16(2):96-103.
Anthony Rosner, PhD
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