RE: [LaWA] Medscape paper on whiplash; rebuttal

[Guest guest]

,

The link to the article is:

http://www.medscape.com/SMA/JSOA/2000/v09.n03/soa0903.05.labo/soa0903.05.labo.html

(I think). As said, it was published in full on Medscape, which you can access at http://www.medscape.com. Medscape is a members-only site, but it is free to join (you then "sign in" using username/password). You will need to be signed up and signed in to access this artcile with this link, I think. I found it by going to the Medscape home page and searching for "Laborde."

Thank you both, and , for sharing your thoughts on this article with us.

Pete Livengood

LaWA Moderator

http://www.LaWashington.org

LAW OFFICE OF PETER G. LIVENGOOD

Seattle, Washington

http://www.LivengoodLaw.com

-----Original Message-----From: Seroussi MD [mailto:drseroussi@...]

An excellent analysis from Dr. Freeman regarding the injury aspects of whiplash. I would like a link to the original article if someone has it, but Dr. Freeman's statements have stand-alone validity. A few comments about disc injury and whiplash:

1. MRI - in most clinical situations, not just whiplash - is proving itself sadly short of being able to "diagnose injury" except in the very rare cases of disc extrusion (i.e. where disc material is clearly dislodged into the spinal canal, not merely bulging or protruding) or marked spinal stenosis. Taken by itself, it is neither specific (i.e. there is a false positive rate, as shown in the cited Jensen study) nor sensitive (i.e. there is a false negative rate, as shown in numerous other studies, some of which have been reviewed in Injury Forum) for picking up neck and back injury. It is merely a clinical tool, and the history and physical exam skills of the health care practitioner are critical for determining the utility of MRI in the vast majority of clinical situations.

2. The Pettersson et al study does not have a direct control group, which would have been preferred. However, severity of MRI findings did roughly correlate with clinical findings and ultimately the need for surgery in the group studied. No doubt some of their whiplash subjects had "false positive" MRI results - where the actual primary neck pain generator was different than that suggested by a disc bulge or protrusion on MRI.

For example, as I tell my patients "MRI shows the facet joint, but generally not pain coming from the facet joint." Recall that facet-mediated pain is likely responsible for over 55% of chronic, (non-radicular) neck pain after whiplash. Not also that the vast majority of neck pain after whiplash is NOT radicular, i.e. does not radiate into the upper extremities and therefore escapes routine detection by MRI, as well as treatment by surgery. I do sometimes get a neck MRI for a patient who is desperate to find out "what's wrong," but I really try to caution them that the scan is fraught with false positives and negatives (I put it in simpler language obviously) and emphasize that their history and exam, together with the practitioner's clinical acumen and grasp of the literature are the most key elements to a reasonable diagnosis and treatment plan.

3. Dr. Freeman has a vast understanding of the low-speed impact literature. However, as a clinician, I will comment that I do witness disc herniations from routine activities of daily living such as a patient pushing their office chair back and hitting a plastic floor guard abruptly, turning their head or body in an awkward manner, etc. I believe and the literature partly supports that pre-existing degenerative changes likely are a risk factor for more severe or more chronic injury in these instances. However, many of these patients with pre-existing DDD are fully or mostly asymptomatic prior to injury . "Degenerative disc disease" as it applies to the spine is an imaging finding, not a diagnosis or a disease. It's a picture, nothing more and nothing less until the clinician puts the picture in the context of the patient's overall history and exam and other findings.

Excellent, Dr. Freeman, my respects to your able pen and gray matter.

For those interested, I have enclosed the Injury Forum review of a landmark article revealing MRI's poor correlation to the clinical picture in the vast majority of cases of low back pain and sciatica.

-----Original Message-----From: Dr. Freeman [mailto:drmfreeman@...]

Dear listmates,

Several of you have written about the article that was published in toto on Medscape, published in the Journal of the Southern Orthopedic Association, regarding whiplash injuries. Below is my response to this very paper, as promised.

February 8, 2001

Letter to the Editor

Journal of The Southern Orthopaedic Association

Volume 9, number 3, page 187-192

Author: J.M. Laborde

Title: Biomechanics of Minor Automobile Accidents: Treatment Implications for Associated Chronic Spine Symptoms

Dear Sir,

Dr. Laborde’s paper on the “biomechanics of minor automobile accidents” was an interesting but highly selective review of the literature. Dr. Laborde chose to cite only the literature or sections of papers that he felt supported his position that whiplash injuries are non-pathologic, and thus ignored the mass majority of the existing literature that contradicts his position.

While Dr. Laborde stated that “disk bulges, protrusions, and herniations are found on lumbar MRI in 80 percent of asymptomatic patients” he did not mention that he was representing one author’s findings in a series of 98 asymptomatic subjects, and the findings of this population does not represent those of the symptomatic population. A careful review of the cited paper, however, reveals a misinterpretation of the authors’ conclusions; 36 percent of the author’s 98 subjects had normal discs, and thus it is not clear from where Dr. Laborde derives his 80 percent figure. The authors of this paper reported that only 52 percent of their subjects had a bulge in at least one level; 27 percent were found to have a protrusion at one level (some of the protrusion subjects also had bulges); and only 1 percent had an extrusion. It is reasonable to state that some asymptomatic people have disc pathology, but this does not allow any inference as to whether symptomatic subjects can also have disc pathology that is causing them symptoms. Pettersson et al. reported on a cohort of 39 whiplash-injured subjects who were followed prospectively for two years following a whiplash injury.[ii] Thirteen of the subjects were found to have disc herniation on MRI at the end of the study period, and only one was asymptomatic. Such a study is a more relevant source of information on whiplash injury and symptomatic disc herniation.

Dr. Laborde further states that “disk herniations are uncommon in front- and side-impact automobile accidents severe enough to cause other serious spinal injuries. He refers to four studies of injuries resulting from moderate- and high-speed motor vehicle crashes. While this is an accurate representation of the findings of the authors of these papers, it is irrelevant to the subject of Dr. Laborde’s paper, since low-speed motor vehicle crashes, particularly rear-end collisions, produce a different mechanism of injury than do high-speed crashes. The widely differing injury mechanisms for low-speed crashes versus higher-speed crashes make comparisons virtually impossible.

Dr. Laborde continues to cite literature that is inapplicable to low-speed motor vehicle crashes when he states, “In laboratory spinal testing; cervical compression, torsion, and flexion do not result in disk herniation.” He goes on to state that “only a combination of lateral bending, hyperflexion, and severe compression can sometimes cause disk herniation.” He then contradicts this statement by stating that “herniation of a degenerated disk frequently occurs without injury.” This is a non sequiter, in that it cannot be true that only extreme trauma comprising all of the elements of lateral bending, hyperflexion, and severe compression can cause a disc herniation, and that such injuries can also occur without injury. Dr. Laborde is mixing experimental cadaveric study with the experience of clinical practice, which clearly illustrates that disc herniation can occur from a variety of causes.

Dr. Laborde feels that “disk abnormality should be attributed to an automobile accident only if it is of a type not normally seen in the aging process, or if there is no compression on MRI and appropriate localized new symptoms or objective findings.” This further contradicts his earlier statement regarding the prerequisites for disc herniation, since from a practical perspective attribution of cause of a disc herniation to a motor vehicle crash is made by clinical history and chronology of symptom onset, and not by an assumption as to the degree of force that is required to cause a disc herniation in a given individual. There is no established threshold for disc injury in the general population; depending on the state of degradation of a disc in a particular individual, symptomatic herniation may occur following any degree of trauma ranging from a sneeze to a life threatening mechanical load.

Dr. Laborde cites several human volunteer crash test studies, including a study by West et al.[iii], Szabo et al., [iv] and a study from Castro et al.[v] as illustrations that there is a level of velocity change (or delta V of the struck vehicle) below which injury is unlikely. In drawing inferences from these studies regarding the real-world population of whiplash injuries, Dr. Laborde is misusing human volunteer crash test studies as epidemiologic studies.

As we mentioned in our 1999 publication of Spine, referenced by Dr. Laborde in his paper, human volunteer crash tests are conducted in a manner that is least likely to result in injury in prepared, healthy, mostly male subjects who are ideally situated in their seats and are least likely to be injured.[vi] Dr. Laborde states that “the studies of Szabo et al. and Castro et al. indicate that thresholds of injury hold in the presence of arthritis and that “patients with soft tissue injury and arthritis have rapid healing of soft tissue injury, as did those without evidence of arthritis. He concludes by stating that short-term symptoms did not result in chronic pain in any of the studies.” Again, it is important to note that Dr. Laborde has lost sight of the fact that these studies were not of real-world injuries, but rather studies of healthy subjects that illustrated that it is possible to undergo human volunteer crash testing without sustaining significant injury. This fact is irrelevant as to whether individuals in real-world crashes can be injured, regardless as to whether one or two crash test volunteers had degenerative changes in their spines at the time of the study.

Dr. Laborde has lost sight of the primary tenets of scientific method; observations are made, hypotheses are developed to explain the observations, and experimental studies are devised to relate the hypotheses to the observations. Dr. Laborde is citing small experimental studies to invalidate the real-world observations that low-speed motor vehicle crashes can and do cause injury.

Dr. Laborde states that “The threshold for spinal injury of an occupant is usually higher than the threshold for vehicle damage. Two thousand volunteer collisions have never produced chronic neck symptoms. Collisions with no vehicle damage would usually not cause neck pain, would be even less likely to cause chronic symptoms.” The cited basis for this statement is an opinion piece published in the Journal of Rheumatology in 1997.[vii] In this editorial by Ferrari and , the authors provide no citation to support their claim of 2,000 crash test studies. My colleagues and I have searched the literature of human volunteer crash tests, and found no more than 140 human volunteers who have participated in vehicle-to-vehicle crash tests (although some of the volunteers were involved in multiple crash tests, these tests are not independent of each other).

Regardless of the number of human volunteer crash tests that have been conducted without injury, it is a fact that some people are injured in low-speed motor vehicle crashes with minimal or no property damage. The largest study ever conducted of insurance claims for injury following motor vehicle crashes showed that 18 percent and 23 percent of women involved in motor vehicle crash with $500 or less of damage were injured.[viii] Other authors have demonstrated cervical disc injuries with radiculopathy in 7 mile-per-hour and less motor vehicle crashes (minimal- to no-damage crashes) in a cohort of 237 real-world crash-injured subjects.[ix]

While it is understandable that Dr. Laborde is interested in furthering his theories that there are psychosocial factors at work in whiplash injury, these theories should not be promulgated at the expense of an evenhanded evaluation of the literature regarding whiplash injuries. Science is best served when all facets of a problem are exposed, not just those that best suit ones present needs.

Very truly yours,

D. Freeman, Ph.D., D.C., M.P.H.

Jensen MC, Brant-Zawadzki MN, Obuchowski N, et al. Magnetic Resonance Imaging of the Lumbar Spine in People Without Back Pain. Nengl J Med. 1994;331(2):69-73.

[ii] Pettersson K, Hildingsson C, Toolanen G, et al. Disc pathology after whiplash injury. Spine 1997;22(3):283-88.

[iii] West DH, Gough JT, Harper TK. Low Speed Rear-end Collision Testing Using Human Subjects. Accident Reconstruction J. 1993;5:22-6.

[iv] Szabo DJ, Welcher JM, RA, et al. Human Occupant Kinematic Response to Low Speed Rear End Impacts. Society of Automotive Engineers Technical Paper Series. 1994;940532:23-5.

[v] Castro Whm, Schilgon M, Meyer S, et al. Do Whiplash Injuries Occur in Low Speed Rear End Impacts? Eur Spine J. 1997;6:366-75.

[vi] Freeman MD, Croft AC, Rosignol AM, et al. A Review and Methodologic Critique of the Literature Refuting Whiplash Syndrome. Spine. 1999;(1)86-98.

[vii] Ferarri R, AS. The Whiplash Syndrome; Common Sense Revisited. J Rheumatol. 1997;24:618-22.

[viii] Farmer CM, Wells JK, Werner JV. The relationship of head restraint position to driver neck injury in rear-end crashes. Insurance Institute for Highway Safety 1998.

[ix] Tencer AF, Mirza SK. Is there a relationship between pre-existing spinal degeneration and whiplash associated symptoms in victims of rear-end auto impacts? Cervical Spine Research Society 27th Annual Meeting - December 16-18, 1999.