Buyer Beware
Chiropractors Call for Reform
Much of the blame for the $100 billion back pain epidemic can be laid at the doorstep of the AMA contends the chiropractic profession.
According to a spokesman from the American Chiropractic Association, “President Obama has said he will make reforming the U.S. healthcare system his top fiscal priority this year by reining in skyrocketing medical costs.” Health care costs will top $8,000 per person this year and the government statisticians estimated that health costs will reach $13,100 per person in 2018, accounting for $1 out of every $5 spent in the economy.[1]
The chiropractic profession believes the high cost of treating back pain is one area to look at, contending if chiropractic care were mainstream, it would save billions annually as well as untold amounts of suffering.
The source of this problems stems from the American Medical Association’s illegal campaign to boycott the much maligned chiropractors whose mainstay, spinal manipulation, has now been shown to be a “proven treatment” for back pain.[2]
Once considered the whipping boy of medicine, research now shows that spinal manipulation is a recommended treatment for both acute and chronic neck and low back pain by 17 international guidelines, including the American College of Physicians and the American Pain Society.
Anthony Rosner, PhD, testified in 2003 before The Institute of Medicine to the growing respect for chiropractic care:
“Today, we can argue that chiropractic care, at least for back pain, appears to have vaulted from last to first place as a treatment option.” [3]
On the other hand, there is increasing bad news for medical doctors who treat back pain comes from the same research that shows little support for drugs, shots and spine surgery.
Dr. Gordon Waddell, orthopedist and author of the book, “The Back Pain Revolution,” confesses that
“Low back pain has been a 20th century health care disaster. Medical care certainly has not solved the everyday symptom of low back pain and even may be reinforcing and exacerbating the problem.”[4]
The call for reform rings loudly from the editors of The BackLetter, a foremost newsletter in the world of spine care.
“The world of spinal medicine, unfortunately, is producing patients with failed back surgery syndrome at an alarming rate…Despite a steady stream of technological innovations over the past 15 years—from pedical screws to fusion cages to artificial discs—there is little evidence that patient outcomes have improved.”[5]
In February of 2009, more research from the University of North Carolina School of Medicine has shown the prevalence of chronic low
“Since the costs of back pain are rising, along with the number of cases, current treatments overall do not seem to be very effective.”[6]
This 3-fold increase is not only alarming and costly, it’s an indictment of the medical methods that have proven so ineffective.
Dr. Richard Deyo also calls for reform:
”People say, ‘I’m not going to put up with it,’ and we in the medical profession have turned to ever more aggressive narcotic medication and more invasive surgery.” [7]
“More people are interested in getting on the gravy train than on stopping the gravy train.”[8]
And typically, patients are railroaded onto the gravy train of drugs, shots, MRIs, and surgery, bypassing the chiropractor’s office in route to surgery.
A study conducted in 1994 compared international rates of back surgeries and found the startling fact that American surgeons are unusually excessive.
According to Richard Deyo, MD,
“The rate of back surgery in the United States was at least 40% higher than any other country and was more than five-times those in England and Scotland. Back surgery rates increased almost linearly with the per capita supply of orthopedic and neurosurgeons in that country.”[9]
This railroad is costly, dangerous, and ignores their own research—it flies in the face of evidence-based medicine. The only way to stop this train is for the federal government to derail it since the AMA has no desire to change tracks and refer these patients to chiropractors.
Without access to spinal manipulation as done by chiropractors, this cost and clinically-effective treatment has led to this epidemic of back pain. This is an unusual case of clinical iatrogenesis [doctor-caused] where physicians do harm by their own treatments, but this harm is also done by boycotting the most effective treatments like chiropractic care.”
Paul Goodley, MD, an orthopedist who popularized manipulative therapy in his book, Release from Pain, also believes the medical bias to this healing art has led to this back pain epidemic.
“The conflict remains so near unimaginable that future historians may well describe the past century as a time of unnecessarily perpetuated pain.” [10]
Chiropractors believe the net effect is the boycott of chiropractic care has contributed greatly to this current epidemic of pain and the costly, unnecessary and often ineffective medical treatments consisting of drugs, shots and surgery.
Not only are proven alternative methods still resisted by physicians, but the old ineffective, expensive medical methods are escalating. Indeed, the gravy train is gaining momentum despite the new guidelines, making one wonder what good are data and evidence-based guidelines when the AMA ignores them when it doesn’t profit?”
Recent studies document the escalating number of questionable medical methods for back pain:
- a 629% increase in Medicare expenditures for epidural steroid injections;
- a 423% increase in expenditures for opioids for back pain;
- a 307% increase in the number of lumbar magnetic resonance images among Medicare beneficiaries; and
- a 220% increase in spinal fusion surgery rates.[11]
This is definitely a case of buyer beware. Don’t think for one moment when you ask a medical doctor about your back problem that you are always getting the best advice based on recent research or scientific guidelines.
Most likely, chiropractors believe, patients will probably be hearing outdated advice from a primary care physician who during his or her medical career has had little actual training in this area of musculoskeletal disorders like back pain.
In fact, many in the medical community now admit the musculoskeletal training of medical students is “woefully inadequate,”[12] but that hasn’t stopped the family physicians from posing as expert and giving outdated advice to the chagrin of chiropractors.
Dr. Scott Boden, Director of the Emory Spine Center, agrees that
“Many—if not most—primary care providers have little training in how to manage musculoskeletal disorders.” [13]
Dr. Richard Deyo also mentioned this problem of medical mistakes and incompetence by some physicians in diagnosis and treatment of low back treatments:
“Calling a [medical] physician a back-pain expert, therefore, is perhaps faint praise—medicine has at best a limited understanding of the condition. In fact, medicines’ reliance on outdated ideas may have actually contributed to the problem.”[14]
Chiropractors don’t appear as experts on medical matters that they’re not trained to diagnose or treat, so why do family physicians feel compelled they can advise patients on matters of the spine that they admittedly have no training or practical expertise?
It’s no secret their outdated treatments are exacerbating the epidemic, harming patients with misdiagnosis and discouraging patients from seeking chiropractic care. This is not ethical or scientific.
The outcry toward the medical mismanagement of back pain comes not only from chiropractors, but a recent two-year study by Consumer’s Medical Resource revealed Fortune 500 corporations spend over $500 million a year on avoidable back surgeries for their workers and lose as much as $1.5 billion in indirect costs associated with these procedures in the form of missed work and lost productivity.[15]
This study, "Back Surgery: A Costly Fortune 500 Burden," found one in three workers recommended for back surgery by their doctor said they avoided an unnecessary procedure after being given treatment options. Some studies comparing surgical and non-surgical treatment outcomes have shown little difference between the two approaches.
"Our research concludes Fortune 500 companies are wasting $500 million each year from more than 13,000 unnecessary back surgeries performed on their employees in the U.S. each year," said David Hines, president and founder of CMR.
According to the study, as many as 100 million working days are lost each year due to back pain. The average cost of back surgery in the U.S. is $36,000 to $38,200, and the reoperation rate is nearly 20%.[16]
In addition, those patients who refused surgery and opted for alternative and less invasive procedures like chiropractic care to treat their back pain reported healthier and more personally satisfying outcomes.
This mirrors a Gallup poll in 1991 that showed chiropractic patients have always been satisfied with their local chiropractors. Gallup recognized that
- Chiropractic care is more patient-friendly than medical care with three times the patient satisfaction rates.
- 90% chiropractic patients felt that their treatment was effective and met or exceeded their expectations.[17]
And chiropractors are quick to tell patients not to assume back surgeries are typically successful as leading orthopedists themselves warn.
Gordon Waddell, orthopedist and author, confessed that
“Sadly, we must conclude that much low back disability is iatrogenic [doctor-caused]…back surgery has been accused of leaving more tragic human wreckage in its wake than any other operation in history.”[18]
According to a study done by Dr. E. Berger, 1,000 workers’ compensation patients who had undergone lumbar spinal, 71% of the single-operation group had not returned to work more than 4 years after the operation, and 95% of the multiple-operations had not returned to work. In none of these cases was there a neurological problem that precluded gainful employment—the failure to return to work was blamed on chronic postoperative pain. [19]
While most people with back problems may think modern medical science is on the cutting edge of this problem, the facts contradict this belief. In fact, the back pain treatment business is riddled with outdated ideas by a biased medical profession, all leading to high costs and ineffective results.
Choosing treatment options for back pain can be a daunting task and “analogous to shopping in a foreign supermarket without understanding the product labels” according to Scott Haldeman, DC, MD, PhD, and treatment options include over 200 different medications, therapies, injections or surgical procedures. [20]
Indeed, buyer beware is fair warning to all in terms of treatments and in terms of qualified doctors.
The call for reform is growing louder and louder to expose the ineffectiveness in back pain management, but the medical establishment isn’t listening to its own experts.
Most treatments have been shown to be expensive, short-term at best, and unnecessary in most cases. This ineffective medical treatment has become a case of throwing good money in after bad. It’s time for a change in treatments, but this won’t happen until there’s a change in attitude.
However loud the call for reform, change comes slowly to the medical profession. If the electronics industry were as slow to change as medicine, we’d still be in the vacuum tube era. The problem is the medical society won’t admit those pesky chiropractors were right all along. It appears they still believe the AMA’s propaganda that chiropractors are quacks even when their own researchers now support our treatment over medical treatments for back pain.
Dr. Scott Haldeman, a leading spokesman in the spine professions with his three degrees as a chiropractor, medical doctor and PhD, suggests there was a longer time lag for treatments that were ultimately refuted.
“For these unsuccessful treatments, there was a median time lag of 44 years from initial discovery to being disproved. For treatments that ultimately proved to be valuable, there was a time lag of ‘only’ 17 years between discovery and scientific validation.”[21]
The glaring question most people must be asking themselves about the back pain epidemic is why has this newfound appreciation for chiropractic care gone unnoticed in the media and by the medical society?
And why has the criticism of medical procedures been so quiet in the lay media?
Except for chiropractic patients and spine researchers who understand the value of chiropractic care, many in the public haven’t learned this lesson due to a very extensive propaganda campaign conducted by the American Medical Association that was revealed in a federal antitrust court in Chicago that began in 1976.
This is a dark chapter in medical history that few people are aware of, but one that lingers on today to shape American attitudes about the chiropractic profession more than most might imagine.
A poignant example of the negativity spewed by the AMA’s propaganda campaign was evident in a survey conducted in 1984 in Oklahoma.
“To many respondents, chiropractors are seen as being fine for many people in the community, but as one said, ‘I wouldn’t want my daughter to marry one.’”[22]
This typifies the split image of chiropractors by the public—on one hand, they are fine, but an inherent prejudice still exists.
So where does this unwarranted skepticism come from? Not from patients who have always given chiropractors high satisfaction rates, nor did it come from the US Public Health Service or Veteran’s Administration and the US Armed Forces that hire chiropractors.
Nor has it come from medical and chiropractic researchers who have stated that spinal manipulation is a “proven treatment” for back pain according to the US Public Health Service:
“This treatment (using the hands to apply force to the back to ‘adjust’ the spine) can be helpful for some people in the first month of low back symptoms. It should only be done by a professional with experience in manipulation.”[23]
This skepticism is not by chance, but it is the result of a campaign going back to the 1960’s by the AMA to “contain and eliminate” chiropractic. It was an array of illegal dirty tricks that were never revealed to the public by the media since many were also co-conspirators in this criminal boycott.
First of all, hands-on spinal care is not new: the history of spinal biomechanics has its origins in antiquity. Egyptian documents written in the 17th century BC described spinal care. By the time of Hippocrates in the 4th century BC, physical means such as traction was being used to correct spinal deformities. The Renaissance produced Leonardo da Vinci who accurately described the anatomy of the spine. The first comprehensive treatise on biomechanics was published by Giovanni Borelli back in 1680, who is considered the “Father of Spinal Biomechanics.”
In many European countries “bonesetters” have treated strains and sprains of the spinal column since time immemorial as a trade passed down from father to son for many generations.[24] Even Queen Victoria who suffered with migraines allegedly was treated by a spinal manipulator.
The origin of chiropractic began is a similar fashion in America when DD Palmer re-discovered the art of spinal manipulation in 1895 and his teachings were carried on by his son, BJ Palmer.
Today, there are over 80,000 licensed chiropractors in 88 countries around the world serving millions of people daily. This age-old art has finally come of age with 37 accredited colleges around the world teaching the science, art, history, and philosophy of this natural form of health care.
Obviously, the art of spinal manipulation has been around for a long, long time as a valued healing art. Despite the AMA’s opposition, spinal manipulation as performed by chiropractors has emerged as one of the oldest, safest and most effective treatment methods for back pain.
Nevertheless, the AMA turned its political and propaganda guns against this healing art and chiropractors for reasons that maintain the medical monopoly through illegal dirty tricks that made the Watergate burglars look like a bunch of amateurs.
The AMA obviously wasn’t sorry for being found guilty as charged since two objectives were accomplished—to ruin the reputations of chiropractors and to contain them to the margins of the healthcare system. The AMA didn’t eliminate chiropractors, but they certainly still work to limit patients’ access to chiropractors by insurance discrimination.
Until there’s a chiropractor in every public hospital, on every workers’ compensation panel, in every VA hospital and on every military base, we cannot say the public is getting the best care for their neck and back pain problems, nor can America say there’s a level playing field and free enterprise in healthcare.
Actually, there are other skeletons in the medical closet that the AMA would like forgotten, including its policy of racism toward black MDs. In July, 2008 the AMA’s House of Delegates finally announced a formal apology for its historical racism toward African American medical doctors.[25] Perhaps with the impending likelihood of our first black president, the AMA began hedging its bet not to still be seen as an elitist and racist organization and offered a contrite apology to its black members, albeit it too little, too late.
While black MDs were forced to sit in the back of the medical bus, chiropractors were thrown under the bus. Plus, unlike black MDs who were isolated, chiropractors were not only segregated, but their reputations were ruined by the AMA’s illegal boycott. So, where do we go now to get our reputation back?
If the AMA is now willing to admit to its prejudicial intolerant past, will the AMA also be as forthcoming about its illegal campaign against the chiropractic profession and turn over a new leaf in its irrational battle against chiropractors? While the AMA is handing out apologies, chiropractors believe the chiropractic profession is due one too.
Not only would a public apology to chiropractors be appropriate, but reparations might be in order. Just think of the millions, if not billions, of dollars diverted from chiropractors’ offices to the surgeons as a result of this illegal boycott. This boycott is clearly a monopoly’s attempt to corner the market, profit greatly, and walk away without any real consequence other than a slap on its hand. Just where is the level playing field of free enterprise?
Back Pain Epidemic: Political iatrogenesis
Aside from the damage done to chiropractors’ reputations and incomes, what else can we attribute to the AMA’s campaign to eliminate chiropractors and their healing art? A case can easily be made that the medical profession itself is responsible for this epidemic of back pain.
Without a doubt, this “lengthy, systematic, successful and unlawful boycott” as the judge proclaimed, has led to the present epidemic of low back pain in America by creating the unwarranted skepticism in the public’s mind as well the prejudice in the medical society.
Indeed, a better description of this form of iatrogenesis may be called political iatrogenesis—harm done by political dirty tricks. By discouraging the use of chiropractic care, the AMA forced people to use less effective medical treatments.
This epidemic is a result of the medical society’s attempt to corner the market of back pain, but in this case, their methods have proven to be less than effective for the vast majority of cases as the recent researchers have concluded.
Imagine the epidemic of tooth decay and gum disease we’d see today if the AMA had been successful in ruining the reputation and practices of dentists.
Well, this is exactly what’s happened as a result of the AMA’s boycott of chiropractic to corner the market and, according to attorney George McAndrews, the ACA’s legal counsel and Wilk trial attorney:
“When patients are forced to take their health problems from a chiropractor to a medical physician who isn’t skilled in that area…that is a funneling of business from the most-skilled to the least-skilled providers.”[26]
The chiropractors believe this suffering and huge expense can be blamed on the AMA’s propaganda campaign to deny Americans the best form of spinal care done by chiropractors, pointing out that Tim Carey, MD, admitted “… current treatments overall do not seem to be very effective.”[27]
To lower costs and improve outcomes, the ACA recommends an integrated, multidisciplinary approach with chiropractors working side by side with orthopedists, physical therapists and neurosurgeons as demonstrated at Bethesda Naval Hospital where a team approach is used very successfully.
Gordon Waddell, orthopedist and author, confirms,
“There is now considerable evidence that manipulation can be an effective method of providing symptomatic relief for some patients with acute LBP.”[28]
Apparently many researchers agree that the team approach is best. According to Dr. Scott Boden, Director of the Emory Spine Center,
“The best thing is to have an organized, integrated approach that uses state-of-the-art and cost-effective care.” [29]
Most guidelines such as the US Public Health Service and the American College of Physicians suggest this integrated approach begins with conservative non-invasive methods like spinal manipulation before narcotic drugs, epidural shots and spine surgery.[30]
Instead, patients are typically treated by their general practitioner with pain pills and muscle relaxants, then when that fails, patients are automatically referred to the surgeon’s office bypassing the chiropractor’s office, driving up the costs by ignoring the safer, cheaper, and more clinically-effective spinal care—spinal manipulative therapy.
Just imagine the thousands if not millions of Americans who’ve been drugged with narcotics, injected with steroids, and had unnecessary spine surgery all due to this irrational bias toward chiropractors. This also explains why 80,000 cases of failed back surgery occur each year in our nation.[31] If every American had access to chiropractors, this pandemic of pain caused by this medical bias would be dramatically reduced.
Without a doubt, the chiropractic profession urges buyers to beware when it comes to drugs, shots or surgery for their back pain.
The advice given to patients by untrained family doctors has proven inadequate, and patients need to know this. The gatekeepers for musculoskeletal disorders should primarily be chiropractors, just as dentists are portal of entrance for teeth and mouth issues.
Today’s chiropractors are better educated than ever before, thoroughly skilled in differential diagnostics, and capable of handling not only back and neck pain, but other musculoskeletal disorders like carpal tunnel wrist pain, jaw pain, and the myriad of other extremity joint disorders that 80% of patients complain about to their family doctors. Rather than drugging them, chiropractors can adjust these joints with very good results.
Not only should chiropractors be angry about this illegal boycott of chiropractors and the epidemic of back surgeries, but so should the public be angry. After all, it was the general public that the AMA has lied to over these many years about the best form of spinal care.
By now you can see this degradation of chiropractors was not self-inflicted nor did it come from any public outrage. It is the total fabrication of the AMA to monopolize health care by demonizing their main rivals,” Smith concluded. “It’s simply a case of medical demagoguery.
Chiropractors today should be heralded as the first healthcare reformists in America, long before it was politically correct.
If it weren’t for the tenacity of the much maligned chiropractors, spinal manipulation would be a lost art today and people would have no freedom of choice other than drugs, shots, and surgery that their own experts now tell us are ineffective treatments.
It’s time for a healthcare revolution, not merely a reform, in the back pain business—a return to free enterprise on a level playing field rather than a monopolistic control by one trade association, the AMA.
Our new president speaks of a new hope and change in America, and I say we need the same in healthcare. We certainly don’t need more of the same drugs, shots and surgery. When the medical profession finally thinks out of this box, it will find the chiropractic profession willing and able to help with this epidemic.
Too many people have suffered too long and it’s time for a change, it’s time for new hope for the epidemic of back pain that the chiropractic profession can deliver best as the facts have shown.
Unfortunately, the AMA isn’t interested in healthcare reform, reducing costs nor is it interested in referring these cases to chiropractors. Everyone, including ardent fiscal conservatives, should be enraged over the billions of dollars lost and the pandemic of pain caused by outdated medical policies that discriminate against the best form of spinal care—spinal manipulation done by chiropractors. This shouldn’t just be a case of the chiropractors with an ax to grind, but everyone—the patients and payers too.
This is certainly a case of buyer beware. Don’t stay trapped in old attitudes, old ineffective concepts, and old medical treatments. It’s time to think out of the box of drugs, shots and surgery and discover the new science of chiropractic spinal care.
[1] Associated Press, Feb. 24, 2009
[2] Bigos S. et al. US Dept. of Health and Human Services, Public Health Service, Agency for Health Care Policy and Research, Clinical Practice Guideline, Number 14: Acute Low Back Problems in Adults AHCPR Publication No. 95-0642, December 1994.
[3] Dr. Tony Rosner, former Director of Research at FCER, testimony before The Institute of Medicine: Committee on Use of CAM by the American Public, Testimony for Meeting, Feb. 27, 2003.
[4] Waddell G. and OB Allan, “A historical perspective on low back pain and disability, “Acta Orthop Scand 60 (suppl 234), 1989.
[5] The BackLetter, vol.12, no. 7, pp.79 July, 2004. The BackPage editorial, The BackLetter, pp. 84, vol. 20, No. 7, 2005.
[6] University of North Carolina School of Medicine (2009, February 18). Chronic Low-back Pain On The Rise: Study Finds ‘Alarming Increase’ In Prevalence. ScienceDaily.
[7] “With Costs Rising, Treating Back Pain Often Seems Futile” by Gina Kolata, NY Times, February 9, 2004.
[8] Reed Abelson, Financial Ties Are Cited as Issue in Spine Study, NY Times, January 30, 2008 .
[9] Cherkin, DC et al., “International comparison of back surgery rates, “ Spine 19 (11): 1201-1206 (1994).
[10] Goodly, PH, Release from Pain, Don’t be a victim of the pain pandemic, 2005. www.Dr.Goodley.com.
[11] Richard A Deyo, MD, MPH Principal Investigator; Co-Investigators. Darryl T.Gray, Sohail Mirza, William Kreuter, Brook Martin, Bryan Comstock; Epidemiology of Spinal Surgery: Rates and Trends; Center for Cost and Outcomes Research, Univ. of Washington, School of Public Health and Community Medicine
[12] Elizabeth A. Joy, MD; Sonja Van Hala, MD, MPH, Musculoskeletal Curricula in Medical Education– Filling In the Missing Pieces, The Physician And Sportsmedicine – Vol 32 – No. 11 – November 2004.
[13] Trubo, R. Fighting Back When Your Back Aches, WebMD.com, July 19, 2004.
[14] Deyo, RA. Low -back pain., Scientific American, pp. 49-53, August 1998.
[15] Fortune 500s Waste Over $500 Million a Year on Unnecessary Back Surgeries for Workers, Consumer's Medical Resource, July 21, 2008.
[16] Ragab A and Deshazo RD, Management of back pain in patients with previous back surgery, The American Journal of Medicine, 2008; 121:272-8.
[17] Gallup Organization, Demographic Characteristics of Users of Chiropractic Services. Princeton, NJ: Gallup, 1991.
[18]Waddell G. and OB Allan, “A historical perspective on low back pain and disability, “Acta Orthop Scand 60 (suppl 234), 1989.
[19] Late postoperative results in 1000 work related lumbar spine conditions, Surgical Neurology 54(2):101–106, 2000.
[20] Scott Haldeman DC, MD, PhD, FRCP(C) and Simon Dagenais DC, PhD. A supermarket approach to the evidence-informed management of chronic low back pain. The Spine Journal, vol. 8, Issue 1, January-February 2008, Pages 1-7.
[21] Refuting Ineffective Treatments Takes Years The BackLetter® 101 Volume 23, Number 9, 2008
[22] “Attitudes toward chiropractic health care in Oklahoma” 1984 survey by Welling & Company sponsored by the Oklahoma Chiropractic Research Foundation in cooperation with the Chiropractic Association of Oklahoma
[23] Bigos S. et al. US Dept. of Health and Human Services, Public Health Service, Agency for Health Care Policy and Research, Clinical Practice Guideline, Number 14: Acute Low Back Problems in Adults AHCPR Publication No. 95-0642, December 1994.
[24] Abhay Sanan, M.D., Setti S. Rengachary, M.D. The History of Spinal Biomechanics, (Neurosurgery, 39:657669, 1996)
Department of Neurosurgery, University of Minnesota Hospital System, Minneapolis, Minnesota.
[25] “AMA apologizes to black doctors for past racism,” by Lindsey Tanner, AP Medical Writer Thu July 10.
[26] Judge Rules on Trigon’s Motion to Dismiss ACA Lawsuit, Dynamic Chiropractic, August 6, 2001
[27] University of North Carolina School of Medicine (2009, February 18). Chronic Low-back Pain On The Rise: Study Finds ‘Alarming Increase’ In Prevalence. Science Daily.
[28]Waddell G. and OB Allan, “A historical perspective on low back pain and disability, “Acta Orthop Scand 60 (suppl 234), 1989.
[29] Trubo, R. Fighting Back When Your Back Aches, WebMD.com, July 19, 2004.
[30] Bigos S. et al. US Dept. of Health and Human Services, Public Health Service, Agency for Health Care Policy and Research, Clinical Practice Guideline, Number 14: Acute Low Back Problems in Adults AHCPR Publication No. 95-0642, December 1994.
[31] Ragab A and Deshazo RD, Management of back pain in patients with previous back surgery, The American Journal of Medicine, 2008; 121:272-8.