This month we are going to discuss the commonly held clinical thought and apparently well documented fact that 90% of all acute low back pain episodes ultimately self-resolve within a 60 day period.

It would appear that this commonly held “fact” in spite of widespread “documentation” and acceptance may not be “factual” after all.

In 1978, the book Clinical Biomechanics of the Spine was published by J.B. Lippincott Company with them releasing the second edition in 1990. The authors were the well credentialed: Augustus A. White, MD, DMed Sci; Professor of Orthopedic Surgery at Harvard Medical School; Orthopedic Surgeon-in-Chief at Beth Israel Hospital in Boston along with Manohar M. Panjabi, PhD; Professor of Orthopedics and Rehabilitation and Mechanical Engineering; Director of Biomechanics Research; Yale University School of Medicine

Widely read and regarded by many as an authoritative text, perhaps the most authoritative text on spinal clinical biomechanics of its time. An important comment was made on page 424 of this text that has not only been widely accepted as truth but has significantly helped in shaping the landscape of low back treatment over the last 29 years:

“There are few diseases [low back pain] in which one is assured improvement of 70% of the patients 3 weeks and 90% of the patients in two months, regardless of the type of treatment employed.” Therefore, “it is possible to build an argument for withholding treatment.”

TWO Critical Questions and Revelation About Commonly Held Thoughts Regarding Low Back Pain And It’s Treatment…

Considering that dependable science rarely if ever is wholly based upon ONE single reference or ONE single opinion, the wide reaching impact of this single statement, begs TWO IMPORTANT questions…

FIRSTLY, From WHERE is this statement derived? (a statement that is both so readily printed in and quoted from a most authoritative reference text)

The highly regarded and respected White and Panjabi give a single reference: Alf Nachemson, MD; The Lumbar Spine, An Orthopedic Challenge; SPINE; Volume 1, Number 1; March 1976; Pages 59-71

Both White and Panjabi with as much credibility in the musculoskeletal field as ANY researchers of the last 100 years, had this to say about the reference to Nachemson:

“An outstanding, well-written review of all aspects of the state of knowledge in 1976.”

Nachemson’s exact quote they were referring to, in SPINE, 1976, is as follows:

“Irrespective of treatment given, 70% of [back pain] patients get well within 3 weeks, 90% within 2 months.”

This 1976 quote by Nachemson is essentially identical in percentages, time, concept and language as used by White and Panjabi in 1990.

This concept of the natural history of an episode of back pain is readily expressed by some of the fields truly elite individuals (Nachemson in SPINE, White & Panjabi in Clinical Biomechanics of the Spine) in some of the most highly regarded publications.

SECONDLY: Where EXACTLY is this statement printed in SPINE derived from? Our source, Nachemson gives us two very specific references:

REFERENCE #1: A St. J Dixon; Progress and Problems in Back Pain Research; Rheumatology and Rehabilitation; Volume 12, Number 4; November 1973; Pages 165-175

However there’s a slight turn this seemingly very straight forward story, surprisingly the Dixon reference is not a study at all. Rather Nachemson’s reference is…

“From a paper read at the Annual Meeting of the British Association for Rheumatology and Rehabilitation, London, March 1973.” (p. 165)

The first two sentences of the article are as follows:

“It is a great honor to be invited to talk to my own Medical School, but I am not noted for my contribution to back pain research nor for my startling observations into the biochemistry of the human intervertebral disc. My only contribution has been to show that patients with non-specific back pain more often do better in a rabbit-wool body belt than in a rigid spinal corset which they are more frequently prescribed.” (p. 165)

Following Dixon’s self depricating comments he spends the bulk of this article commenting on current and future directions for back pain research. The end of the article transcribes an informal question and answer session between the author and the audience. Dixon’s discussion includes comments such as: “Discs contain no pain nerve endings, so cannot hurt.” (p. 170)

Needless to say, not only was Dixon NOT an expert in the field of low back pain as he openly admits but in addition much has changed in the years since he delivered this speech in 1973, as all of us now know it is well and firmly established that the disc IS IN FACT innervated (1, 2) and is a very common (if not the most common) producer of chronic low back pain (3, 4, 5, 6, 7).

It is quite clear, from Dixon’s own opening admission, he is not an expert on back pain, nor is he a back pain researcher of any order.

To seemingly add to the confusion, Dixon does reference the following statistics:

“Of those who seek advice [for back pain] from their family doctors, 44% are better in one week irrespective of treatment and 86% are better in one month. Only 14% drag on longer than this. It takes little imagination to see that any treatment for acute back pain will have a high proportion of rapid successes. Manipulation, whether by osteopaths, chiropractors, registered medical practitioners, or physiotherapists, has to be judged against this background.”

Note the following table:

White & Panjabi Clinical Biomechanics of the Spine 1990	Nachemson SPINE 1976	Dixon RHEUMATOLOGY and REHABILITATION 1973
70% improvement in 3 weeks	70% well within 3 weeks	44% better in 1 week
90% improvement in 2 months	90% well within 2 months	86% better in 1 month
Reference Nachemson	Reference Dixon	Reference Fry

 

This investigation of the literature has turned into solving an unexpected mystery of sorts…

Here we have two very well decorated and authoritative authors (White & Panbjabi, Nachemson) in two extremely authoritative publications (Clinical Biomechanics of the Spine, SPINE, respectively), basing the natural history of back pain upon a lecture given by an individual (Dixon) who self admits he is no authority or researcher in spinal problems or back pain. Remarkable as it may seem, Nachemson’s poor reference of Dixon has laid the powerful groundwork for a widely held fact that ultimately appears to be little more than one mans off handed observation.

When you actually carefully examine the numbers…

Dixon states that 44% of the patients are “better” in 1 week.

Nachemson states that 70% of the patients are “well” within 3 weeks.

Not only are the numbers and time frames substantially different, the word “better” used by Dixon can imply any degree of improvement, while the word “well” used by Nachemson implies that the issue has completely resolved.

As if this entire line of discussion wasn’t convoluted enough… the 86% number used by Dixon in 1 month became 90% within 2 months by Nachemson.

It would seem apparent that the editors of SPINE in 1976 did not check or read the Dixon reference quoted by Nachemson, nor did White & Panjabi when they referenced him and quoted his ERROR exactly.

Of equal importance to note, the journal used by Dixon; Rheumatology and Rehabilitation, Volume 12, Number 4, 1973, is not indexed at all by PubMed.

Considering that PubMed searches the indexed articles in the National Library of Medicine in this authors opinion this makes Dixon’s comments and conclusions drawn from them even more suspect.

When this lack of indexing is observed you suddenly realize that this often quoted article by Dixon;

1. cannot easily be found by doing a PubMed data base search, by using either the journal (Rheumatology and Rehabilitation) or the author (Dixon).
2. Because this article is difficult to find, and because those who reference it do so remarkably poorly, it suggests that few who reference Dixon are actually reading his article.
3. It appears more likely that an individual (Nachemson) read the article by Dixon, misquoted him, proceeded to publish the error, and others are reading the error from an otherwise credible Nachemson and repeating it verbatim.
4. Additionally, the Nachemson article is in the very first issue of SPINE, Volume 1, Number 1, March 1976. In 1976, SPINE was also not indexed in PubMed, and one cannot find this article by Nachemson by searching PubMed using either the journal (SPINE) nor the author (Nachemson). SPINE was not indexed by PubMed until 2 years later, beginning in March of 1978.

As I stated earlier, Nachemson used two references, the reference other than Dixon: The SECOND REFERENCE was, Penntti M. Rissanen; The Surgical Anatomy and Pathology of the Supraspinous and Interspinous Ligaments of the Lumbar Spine With Special Reference to Ligament Ruputres; ACTA ORTHOPAEDICA SCANDINAVICA; Supplement Number 46;1960; Pages 1-100

This second reference by Nachemson for comparison sake is 100 PAGES LONG. As the title suggests, this article is not related to the topic of the natural history of back pain.

As a matter of fact at no place in the article is there any discussion of the natural history of back pain in any way shape or form.

There are no numbers related to the percentages and time frame for back pain improvement, becoming better, or becoming well.

The Rissanen article is a study of 306 cadavers evaluating ligament histology, fatty degeneration as a function of age, and incidence of adult rupture of the interspinous ligaments.

Considering these facts, in discussing the natural history of low back pain, the referencing of White & Panjabi in Clinical Biomechanics of the Spine, Nachemson in SPINE 1976, or Dixon in Rheumatology and Rehabilitation 1973 is completely inappropriate.

These Clear Observations Show That The Natural History Of Low Back Pain Statistics Used In These References Are The Erroneous Quoting Of A Non-Existent Study From A Non-Expert On The Topic That Was Published In A Non-Pubmed Indexed Journal. Yet, Sadly, Dixon In Particular, Continues To Be Referenced On The Topic Of The Natural History Of Low Back Pain.

Although Dixon is the most often end reference of the natural history of back pain, a review of Dixon’s article finds that Dixon actually quotes another article as well…J Fry; Advisory Services Colloquia; “Back Pain and Soft Tissue Rheumatism”; Advisory Services (Clinical & General) Ltd., London; Number 1; 1972; Page 8

A COLLOQUIA is “a gathering of scholars to discuss a given topic over a period of a few hours to a few days.” Thirteen individuals took part in this in this colloquium. Dr. J Fry, MD, is listed as a general practitioner from London. Dr. Fry’s published contribution to this colloquium includes the following:

In an average [general practitioner] practice each year 125 patients could be expected for soft tissue rheumatism or acute back pain.

“Of these 125 patients, 50 would be likely to be suffering from acute back pain and 25 from acute neck pain.”

“44% of the patients with acute low back pain lost their symptoms in less than one week and 82% in less than 4 weeks.”

Dr. Fry makes it abundantly clear that these numbers are from a retrospective review of his general practitioner practice of acute low back pain patients.

Dr. Fry provides no information regarding how he evaluated his patients and their progress or lack there of. Equally he fails to discuss how many patients he used to establish these statistics.

Consequently and shockingly these statistics by Dr. Fry are rendered completely meaningless and should under no circumstances be referenced as authoritative in any way shape or form on the natural history of low back pain.

In addition, in the same short section by Dr. Fry in this colloquium it is stated:

“It was agreed that it was the patients whose symptoms did not rapidly clear up who often formed part of the osteopath’s clientele.”

One interpretation of this comment is that osteopaths (and chiropractors as well) are more likely to treat patients who are chronic, not acute; patients who did not respond to symptomatic general practitioner medical management; patients who are more difficult to manage and resolve.

A more recent group of researchers, led by professor Peter Croft (published in the British Medical Journal) actually took the time to evaluate the statistics on the natural history of low back pain that are frequently attributed to Dixon, and they unequivocally show Dixon’s statistics to be false.

Once again, in spite of their conclusions they too misquote Dixon, it is absolutely clear that the Croft group did NOT actually READ the Dixon article.

Here is the review of the Croft Group article, the results speaks for themselves:

Outcome of low back pain in general practice: a prospective study; British Medical Journal; May 2, 1998; Vol. 316, pp. 1356-1359; Peter R Croft, Gary J Macfarlane, Ann C Papageorgiou, Elaine Thomas, Alan J Silman; KEY MESSAGES FROM AUTHORS:

1)It is widely believed that 90% of episodes of low back pain seen in general practice resolve within one month.

2)While 90% of subjects consulting general practice with low back pain ceased to consult about the symptoms within three months, most still had substantial low back pain and related disability.

3)Only 25% of the patients who consulted about low back pain had fully recovered 12 months later.

KEY POINTS FROM THIS ARTICLE INCLUDE:

1)This prospective study of 463 patients with an acute episode of low back pain agrees with numerous other studies that indicate that approximately 90% of such patients will stop consulting their doctor about their back within three months. In this study the number was actually 92%.

2)However, this study is adamant that NOT seeing a doctor for a back problem does NOT mean that the back problem has resolved. This study showed that 75% of the patients with a new episode of low back pain have continued pain and disability a year later, even though most are not continuing to go to the doctor.

3)The belief that “90% of episodes of low back pain seen in general practice resolve within one month” is false, and based primarily upon one flawed study published in 1973 by Dixon. [As noted above, Dixon is NOT a study, and should not be referred to as such.]

4)It is generally believed that most low back pain episodes will be “short lived and that ’80-90% of attacks of low back pain recover in about six weeks, irrespective of the administration or type of treatment.’” This belief is untrue, false.

5)Many patients seeing their general practitioner for the first time with an episode of back pain will still have pain or disability 12 months later but not be consulting their doctor about it. [Very Important]

6)Low back pain should be viewed as a chronic problem with an untidy pattern of grumbling symptoms and periods of relative freedom from pain and disability interspersed with acute episodes, exacerbations, and recurrences.

7)90% of episodes of low back pain DO NOT end in complete recovery within a few months.

Important quotes from this article include:

“It is generally believed that most of these episodes [of low back pain] will be short lived and that ’80-90% of attacks of low back pain recover in about six weeks, irrespective of the administration or type of treatment.’”

These authors “investigated the claim that 90% of episodes [of low back pain] resolve within a month.”

“By three months after the [initial] consultation with their general practitioner, only a minority of patients with low back pain had recovered.”

“There was little increase in the proportion who reported recovery by 12 months, emphasizing the recurrent and persistent nature of this [low back pain] problem.”

“The findings of our interview study are in sharp contrast to the frequently repeated assumption that 90% of episodes of low back pain seen in primary care will have resolved within a month.”

“However, the results of our consultation figures are consistent with the interpretation that 90% of patients presenting in primary care with an episode of low back pain will have stopped consulting about this problem within three months of their initial visit. The original article to which the statement of ‘90% recovery’ can be traced drew on a record review in one general practice.” [Dixon AStJ. Progress and problems in back pain research. Rheumatol Rehabil 1973; 12(4): 165-175.]

“The inference that the patients have completely recovered [becausethey have stopped going to the doctor] is clearly not supported by our data.”

“We should stop characterising low back pain in terms of a multiplicity of acute problems, most of which get better, and a small number of chronic long term problems. Low back pain should be viewed as a chronic problem with an untidy pattern of grumbling symptoms and periods of relative freedom from pain and disability interspersed with acute episodes, exacerbations, and recurrences. This takes account of two consistent observations about low back pain: firstly, a previous episode of low back pain is the strongest risk factor for a new episode, and, secondly, by the age of 30 years almost half the population will have experienced a substantive episode of low back pain. These figures simply do not fit with claims that 90% of episodes of low back pain end in complete recovery.”

In conclusion and in this authors opinion it is time for all credible publications to stop referencing White and Panjabi in Clinical Biomechanics of the Spine 1990, Nachemson in Spine 1976, and Dixon in Rheumatology and Rehabilitation 1973, as to the natural history of low back pain.

The 90% “recovery” rate as the natural history of low back pain in these references is absolutely and unequivocally erroneous and the byproduct of misquoting of a non-existent study from a non-expert on the topic that was published in a non-PubMed indexed journal.

In addition, the 90% recovery myth has subsequently been PROVEN to be false. It is no wonder consistent success in conservative management of these types of cases has remained elusive. Quite possibly getting high QUALITY studies properly referenced will make for a more optimistic future in the conservative treatment of these cases

REFERENCES

1)Bogduk N, Tynan W, Wilson AS. The nerve supply to the human lumbar intervertebral discs. J Anat. 1981 Jan;132(Pt 1):39-56.

2)Bogduk N. The innervation of the lumbar spine. Spine. 1983 Apr;8(3):286-93.

3)Kuslich SD, Ulstrom CL, Michael CJ. The tissue origin of low back pain and sciatica: a report of pain response to tissue stimulation during operations on the lumbar spine using local anesthesia. Orthop Clin North Am. 1991 Apr;22(2):181-7.

4)Freemont AJ, Peacock TE, Goupille P, Hoyland JA, O’Brien J, Jayson MI.

Nerve ingrowth into diseased intervertebral disc in chronic back pain. Lancet. 1997 Jul 19;350(9072):178-81.

5)Coppes MH, Marani E, Thomeer RT, Groen GJ. Innervation of “painful” lumbar discs. Spine. 1997 Oct 15;22(20):2342-9.

6)Freemont AJ, Watkins A, Le Maitre C, Baird P, Jeziorska M, Knight MT, Ross ER, O’Brien JP, Hoyland JA. Nerve growth factor expression and innervation of the painful intervertebral disc. J Pathol. 2002 Jul;197(3):286-92.

7)Peng B, Wu W, Hou S, Li P, Zhang C, Yang Y. The pathogenesis of discogenic low back pain. J Bone Joint Surg Br. 2005 Jan;87(1):62-7.

Historic Article Review

In recent years the media and certain factions of the health care industry have brought the discussion of the safety and or risk of analgesic drugs to the public consciousness.

Certainly patients appear to have more questions regarding their medications than ever before.

And especially considering the considerable part these drugs tend to play in conservative management of many musculo-skeletal conditions it seems appropriate to evaluate this topic at least in part.

In this column this month I’ll be looking at an article entitled:

Risk of Kidney Failure Associated with the Use of Acetaminophen, Aspirin, and Nonsteroidal Antiinflammatory Drugs

It was originally published in the New Eng J Med, Number 25, Volume 331:1675-1679,
December 22, 1994 by Thomas V. Perneger, Paul K. Whelton, and Michael J. Klag

In the abstract the authors describe as the background of the piece as the concept that people who take analgesic drugs frequently may be at increased risk of end-stage renal disease (ESRD), but the extent of the risk remains unclear.

Determining this risk appears to have been the desired outcome of the study.

The authors proceeded to study 716 patients treated specifically for ESRD and 361 other subjects used as controls who were of similar age. The authors also note that all participants were from Maryland, Virginia, West Virginia and Washington, DC.

All of those participating in the study were interviewed by telephone regarding past use of these medications containing acetaminophen, aspirin, and other nonsteroidal antiinflammatory drugs (NSAIDs).

Each analgesic drug was evaluated for average use per patient per year (in pills per year) and the accumulated intake over time as well (in total pills).

These findings then were examined in an effort to determine their association with ESRD if any…

The results appeared to be significant in that acetaminophen usage did in fact have a correlation with an increased risk of ESRD based upon dosage.

The study participants who used an average of 0-104 pills per year was used as a reference marker.

For the subjects who took 105-365 pills on average per year their odds ratio for contracting ESRD was 1.4.

Those taking 366 or more pills per year after adjustments for race, sex, age and intake of OTHER analgesic drugs, their odds ratio for contracting ESRD was 2.1.

When lifetime consumption by these subjects was evaluated those who had taken less than 1000 pills containing acetaminophen in their lifetime were used as the reference group.

For those who had taken 1000-4999 pills cumulatively in their lifetime their odds ration for contracting ESRD was 2.0 and 2.4 for those at 5000 or more pills lifetime.

Clearly when all is said and done, the authors did in fact demonstrate at least some relationship between ESRD and acetaminophen usage… approximately an 8-10% overall increase in incidence was attributable to acetaminophen use.

Aside from acetaminophen as I said earlier, NSAIDs as a group and asprin were also evaluated using similar criteria…

The cumulative dose of 5000 or more pills over a lifetime was in fact associated with an increased odds ratio of ESRD of a sizeable 8.8. However aspirin was NOT shown to have a relationship to the increased insidence of ESRD.

The authors Perneger, Whelton and Klag’s final conclusion was simply that those who often take acetaminophen or NSAIDs have an increased risk of ESRD, but not those who often take aspirin.

Perneger, Whelton and Klag’s article was also accompanied by an editorial entitled “Drug-Induced End-Stage Renal Disease” which was also published in NEJM, Volume 331, Number 25:1711-1712. December 22, 1994

The commentary from the follow up editorial piece was as follows…

“The advertisement and sale of analgesic drugs correlate better with the geographic distribution of analgesic-associated nephropathy than do any other factors, with high rates of both in Switzerland, Belgium, Austria, and the southeastern United States.”

“The incidence of analgesic nephropathy has been dramatically reduced in Sweden and Australia, mainly because the over-the-counter sale of combination analgesics has been prohibited.”

Reduced consumption of acetaminophen could lower the incidence of ESRD by 8 to 10 percent with a range of 2 to 20 percent.

In summary and conclusion these two articles show us several KEY POINTS, each of which I’ve noted below…

(1) In the 1950s, analgesics containing phenacetin was shown to damage the kidney, and withdrawn from the market.

(2) Acetaminophen (Tylenol) is a metabolite of phenacetin.

(3) Light pain drug use was defined as 0 to 104 pills per year, or 0 to 2 pills per week.

(4) Moderate pain drug use was defined 105 to 365 pills per year, or up to 1 pill per day.

(5) Heavy pain drug use was defined 366 or more pills per year, or more than 1 pill per day.

(6) Low cumulative pain drug intake was defined as 0 to 999 pills.

(7) Medium cumulative pain drug intake was defined as 1000 to 4999 pills.

(8) High cumulative pain drug intake was defined as 5000 or more pills.

(9) Those taking 105 to 365 acetaminophen pills per year had increased ESRD by 1.4. (40%)

(10) Those taking 366 or more acetaminophen pills per year had increased ESRD by 2.1. (110%)

(11) Taking 1000 to 4999 acetaminophen pills in their lifetime increased ESRD by 2.0. (100%)

(12) Taking 5000 or more acetaminophen pills in their lifetime increased ESRD by 2.4. (140%)

(13) 8 to 10 percent of the overall incidence of ESRD is attributable to acetaminophen use.

(14) A cumulative dose of 5000 or more pills containing NSAIDs increased the odds of ESRD 8.8. (780%)

(15) This study probably underestimated the risk because it is difficult to track over-the–counter drug use.

(16) Countries, including the USA with the highest advertisement and sale of analgesic drugs have the highest incidence of analgesic-associated nephropathy.

(17) The incidence of analgesic nephropathy is lowest where the sale of over-the-counter analgesics is prohibited.