Back Pain Surgery Avoidance and Chiropractic
America’s Pain Crisis
Judy Foreman was educated at Harvard, and has been a Lecturer on Medicine at Harvard’s Medical School. In 2014, she published a book titled (1):
A Nation in Pain
Healing Our Biggest Health Problem
Ms. Foreman notes that of the 238 million adults in America, approximately half of them have chronic daily pain. The conservative estimate of the direct costs and lost productivity resulting from this pain is up to $635 billion yearly.
Americans pay $113 billion yearly for Social Security Disability benefits (2), and it’s not enough. Our Social Security Disability program is paying out $200 billion yearly. Political newspapers are buzzing about the prediction that the Social Security Disability Trust Fund will go broke next year (2016) (3). Fifteen million Americans are on Social Security Disability, and new applications average 200,000 monthly (2). The primary condition for which Americans apply for and are granted Social Security Disability is “musculoskeletal system and connective tissue” disorders, primarily back pain (2).
The drugs used to treat chronic pain are themselves creating yet another crisis. The political magazine, Time published a cover article titled (4):
They’re the most powerful painkillers ever invented;
And they’re creating the worst addiction crisis America has ever seen;
The price of Relief; Why America can’t kick its painkiller problem
This article makes these points:
- “Around the nation, doctors so frequently prescribe the drugs known as opioids for chronic pain conditions like arthritis, migraines and lower back injuries that there are enough pills prescribed every year to keep every American adult medicated around the clock for a month.” “The result is a national epidemic.”
- “Now, 4 of 5 heroin addicts say they came to the drug from prescription painkillers.”
- “By 2011 the number of opioid prescriptions written for pain treatment had tripled to 219 million.”
- “By 2011, 17,000 Americans were dying every year from prescription opioid overdoses.”
- “The American Academy of Neurology last year concluded that the risks of long-term opioid treatment for headaches and chronic low back pain likely outweighed the benefits.”
Also in 2015, the newspaper the Wall Street Journal reviewed a booked titled Dreamland in an article titled The Great Opiate Boom (5). This article makes these points:
- “Children of the most privileged group in the wealthiest country in the history of the world were getting hooked and dying in almost epidemic numbers from substances meant to, of all things, numb pain.”
- These “prescriptions [opioids] for chronic pain rose from 670,000 in 1997 to 6.2 million in 2002.”
In June 2015, the front page of the newspaper USA Today published an article titled Heroin use surges among women, middle-class (6). This article makes these points:
- “Heroin use is reaching into new communities—addicting more women and middle-class users—as people hooked on prescription painkillers transition to cheaper illegal drugs.”
- “About 75% of new heroin users first became hooked on prescription opiates.”
In 2013, the Wall Street Journal quantifies chronic pain location by citing the Centers for Disease Control and Prevention, and the World Health Organization (7):
28.1% Low Back Pain
19.5% Knee Pain
16.1% Severe Headache or Migraine
15.1% Neck Pain
09.0% Shoulder Pain
07.6% Finger pain
07.1% Hip Pain
Back pain is at the center of America’s pain and disability crisis. It has been know for 40 years that the structure primarily responsible for back pain, especially for chronic back pain, is the intervertebral disc:
- In 1976, internationally respected orthopedic surgeon Alf Nachemson published his detailed review on back pain in the journal Spine (8), in which he states:
“The intervertebral disc is most likely the cause of the pain.”
- In 1981, anatomist and physician Nikoli Bogduk published an extensive review of the literature on the topic of disc innervation, along with his own primary research in the Journal of Anatomy (9). Dr. Bogduk states:
“The lumbar intervertebral discs are supplied by a variety of nerves.”
“Clinically, the concept of ‘disc pain’ is now well accepted.”
- In 1987, the journal Spine published Dr. Vert Mooney’s Presidential Address of the International Society for the Study of the Lumbar Spine (10). In this article, Dr. Mooney states:
“We know that 10% of back ‘injuries’ do not resolve in 2 months and that they do become chronic.”
“Persistent pain in the back with referred pain to the leg is largely on the basis of abnormalities within the disc.”
“Where is the pain coming from in the chronic low-back pain patient? I believe its source, ultimately, is in the disc. Basic studies and clinical experience suggest that mechanical therapy is the most rational approach to relief of this painful condition.”
- In 1991, Stephen Kuslich and colleagues published an article in the journal Orthopedic Clinics of North America (11). The authors performed 700 lumbar spine operations using only local anesthesia to determine the tissue origin of low back and leg pain, and they present the results on 193 consecutive patients studied prospectively. They state:
“Back pain could be produced by several lumbar tissues, but by far, the most common tissue or origin was the outer layer of the annulus fibrosis.”
- In 2006, researchers from Japan published an article in the journal Spine showing the results of a sophisticated immunohistochemistry study of the sensory innervation of the human lumbar intervertebral disc (12). These authors note:
“Many investigators have reported the existence of sensory nerve fibers in the intervertebral discs of animals and humans, suggesting that the intervertebral disc can be a source of low back pain.”
“Both inner and outer layers of the degenerated lumbar intervertebral disc are innervated by pain sensory nerve fibers in humans.”
Pain neuron fibers are found in all human discs that have been removed because they are the source of a patient’s chronic low back pain.
The nerve fibers in the disc, found in this study, “indicates that the disc can be a source of pain sensation.”
- In 2011, researchers from the University/Medical College of Virginia published a study in the journal Pain Medicine in which they quantified the structural source of low back pain in which diagnostic procedures were performed on 170 back pain patients (13). The authors note:
“Our data confirm the intervertebral disc as the most common etiology of chronic low back pain in adults.”
- In 2015, a team from Naples, Italy, published a study in the European Journal of Radiology, in which they present an extensive review of the literature pertaining to spinal pain (14). The authors note:
“Spinal pain, and especially low back pain (LBP), represent the second leading cause for a medical consultation in a primary care setting and is a leading cause of disability worldwide.”
The most frequent cause of LBP is “internal disc disruption and is referred to as discogenic pain.” “Internal disc disruption refers to annular fissures, disc collapse and mechanical failure, with no significant modification of external disc shape, with or without endplates changes.”
Discogenic pain is “considered as the most frequent cause of chronic low back pain.” Discogenic pain secondary to internal disc disruption is the main cause of chronic LBP and disability.
A central theme in the back pain literature is that discogenic back pain is prevalent, and probably accounts for the majority of back pain complaints within the American Society. Chiropractic / manipulative management of patients with back and/or leg pain secondary to nerve compression has a long and impressive history of good clinical outcomes with very low risks. Representative studies include:
- In 1954, RH Ramsey, MD published a study in the Instructional Course Lectures of the American Academy of Orthopedic Surgeons (15). Dr. Ramsey states:
“The conservative management of lumbar disk lesions should be given careful consideration because no patient should be considered for surgical treatment without first having failed to respond to an adequate program of conservative treatment.”
“From what is known about the pathology of lumbar disk lesions, it would seem that the ideal form of conservative treatment would theoretically be a manipulative closed reduction of the displaced disk material.”
- In 1969, physicians JA Mathews and DAH Yates from the Department of Physical Medicine, St. Thomas’ Hospital, London, published a study in the British Medical Journal (16). These authors evaluated a number of patients that presented with an acute onset of low back and buttock pain who did not respond to rest. Diagnostic epidurography showed a clinically relevant small disc protrusion, along with antalgia and positive lumbar spine nerve stretch tests. These patients were then treated with manipulations of the lumbar spine. The manipulations were repeated until abnormal symptoms and signs had disappeared. Following the manipulations there was resolution of signs, symptoms, antalgia, and reduction in the size of the protrusions.
- Also in 1969, BC Edwards compared the effectiveness of heat/massage/exercise to spinal manipulation in the treatment of 184 patients that were grouped according to the presentation of back and leg pain. The study was published in the Australian Journal of Physiotherapy (17). This study was considered to be “a well-designed, well executed, and well-analyzed study.” (18)
“This study certainly supports the efficacy of spinal manipulative therapy in comparison with heat, massage, and exercise. The results (80 – 95% satisfactory) are impressive in comparison with any form of therapy.”
- In 1977, the third edition of Orthopaedics, Principles and Their Applications was published (19). The author, Samuel Turek, MD (d. 1986), was a Clinical Professor, Department of Orthopedics and Rehabilitation at the University of Miami School of Medicine. In the section pertaining to the protruded disc, Dr. Turek makes the following observations:
“Manipulation. Some orthopaedic surgeons practice manipulation in an effort at repositioning the disc. This treatment is regarded as controversial and a form of quackery by many men. However, the author has attempted the maneuver in patients who did not respond to bed rest and were regarded as candidates for surgery. Occasionally, the results were dramatic.
Technique. The patient lies on his side on the edge of the table facing the surgeon, and the uppermost leg is allowed to drop forward over the edge of the table, carrying forward that side of the pelvis. The uppermost arm is placed backward behind the patient, pulling the shoulder back. The surgeon places one hand on the shoulder and the other on the iliac crest and twists the torso by pushing the shoulder backward and the iliac crest forward. The maneuver is sudden and forceful and frequently is associated with an audible and palpable crunching sound in the lower back. When this is felt, the relief of pain is usually immediate. The maneuver is repeated with the patient on the opposite side.”
- In 1985, Dr. Kirkaldy-Willis, a Professor Emeritus of Orthopedics and director of the Low-Back Pain Clinic at the University Hospital, Saskatoon, Canada, published an article in the journal Canadian Family Physician (20). In this study, the authors present the results of a prospective observational study of spinal manipulation in 283 patients with chronic low back and leg pain. All 283 patients in this study had failed prior conservative and/or operative treatment, and they were all totally disabled. These patients were given a two or three week regimen of daily spinal manipulations by an experienced chiropractor. Eighty-one percent of the patients with referred pain syndromes subsequent to joint dysfunctions achieved a good result. Forty-eight percent of the patients with nerve compression syndromes achieved a good result.
- In 1987, physicians Paul Pang-Fu Kuo and Zhen-Chao Loh published a study pertaining to lumbar disc protrusions and spinal manipulation in the journal Clinical Orthopedics and Related Research (21). Drs. Paul Pang-Fu Kuo and Zhen-Chao Loh are from the Department of Orthopedic Surgery, Shanghai Second Medical College, and Chief Surgeon, Department of Orthopaedic Surgery, Rui Jin Hospital, Shanghai, China. They note that manipulation has been used in Chinese healthcare for thousands of years, and by the Tang Dynasty (618-907 AD), “manipulation was fully established and became a routine for the treatment of low back pain.”
In their study, they performed a series of eight manipulations on 517 patients with protruded lumbar discs and clinically relevant signs and symptoms. Their outcomes were quite good, with 84% achieving a successful outcome and only 9% not responding. Only 14 % suffered a reoccurrence of symptoms at intervals ranging from two months to twelve years. Based upon their results, Drs. Kuo and Loh make these statements:
“Manipulation of the spine can be effective treatment for lumbar disc protrusions.”
“Most protruded discs may be manipulated. When the diagnosis is in doubt, gentle force should be used at first as a trial in order to gain the confidence of the patient.”
- In 1989, the Journal of Manipulative and Physiological Therapeutics published a case study of a patient with an “enormous central herniation lumbar disc” who underwent a course of side posture manipulation (22). The patient improved considerably with only 2 weeks of treatment. The authors state:
“It is emphasized that manipulation has been shown to be an effective treatment for some patients with lumbar disc herniation.”
- In 1990, Dr. TW Meade published the results of a randomized comparison of chiropractic and hospital outpatient treatment in the treatment of low back pain. This trial involved 741 patients and was published in the British Medical Journal (23). The patients were followed for a period between 1–3 years. Key points presented in this article include:
“Chiropractic treatment was more effective than hospital outpatient management, mainly for patients with chronic or severe back pain.”
“There is, therefore, economic support for use of chiropractic in low back pain, though the obvious clinical improvement in pain and disability attributable to chiropractic treatment is in itself an adequate reason for considering the use of chiropractic.”
“Patients treated by chiropractors were not only no worse off than those treated in hospital but almost certainly fared considerably better and that they maintained their improvement for at least two years.”
“The results leave little doubt that chiropractic is more effective than conventional hospital outpatient treatment.”
- In 1993, chiropractor J. David Cassidy, chiropractor Haymo Thiel, and physician William Kirkaldy-Willis published a “Review Of The Literature” pertaining to side posture manipulation for lumbar intervertebral disk herniations. Their article appeared in the Journal of Manipulative and Physiological Therapeutics (24). Based upon their review of the literature and their own experiences, these authors state:
“The treatment of lumbar disk herniation by side posture manipulation is not new and has been advocated by both chiropractors and medical manipulators.”
“The treatment of lumbar intervertebral disk herniation by side posture manipulation is both safe and effective.”
- In 1995, chiropractors PJ Stern, Peter Côté, and David Cassidy published a study in the Journal of Manipulative and Physiological Therapeutics (25). They retrospectively reviewed the outcomes of 59 consecutive patients complaining of low back and radiating leg pain, and were clinically diagnosed as having a lumbar spine disk herniation. Ninety percent of these patients reported improvement of their complaint after chiropractic manipulation. They concluded:
“Based on our results, we postulate that a course of non-operative treatment including manipulation may be effective and safe for the treatment of back and radiating leg pain.”
- In 2003, the journal Spine published a randomized clinical trial involving the nonsteroidal anti-inflammatory COX-2 inhibiting drugs Vioxx or Celebrex v. needle acupuncture v. chiropractic manipulation in the treatment of chronic neck and back pain (26). Chiropractic was better than 5 times more effective than the drugs and better than twice as effective as needle acupuncture in the treatment of chronic spine pain. Chiropractic was able to accomplish the clinical outcome without any reported adverse effects. One year after the completion of this 9-week clinical trial, 90% of the original trial participants were re-evaluated to assess their clinical status. The authors discovered that only those who received chiropractic during the initial randomization benefited from a long-term stable clinical outcome (27).
- In 2006, physicians Valter Santilli, MD, Ettore Beghi, MD, Stefano Finucci, MD, published an article in The Spine Journal (28). Their study was a randomized double-blind clinical trial of active and simulated chiropractic spinal manipulations in the treatment of acute back pain and sciatica with disc protrusion. The study used 102 patients. The manipulations or simulated manipulations were done 5 days per week by experienced chiropractors for up to a maximum of 20 patient visits, “using a rapid thrust technique.” The authors noted the following:
“Active manipulations have more effect than simulated manipulations on pain relief for acute back pain and sciatica with disc protrusion.”
“At the end of follow-up a significant difference was present between active and simulated manipulations in the percentage of cases becoming pain-free (local pain 28% vs. 6%; radiating pain 55% vs. 20%).”
“Patients receiving active manipulations enjoyed significantly greater relief of local and radiating acute LBP, spent fewer days with moderate-to-severe pain, and consumed fewer drugs for the control of pain.”
“No adverse events were reported.”
- In 2014, a group of multidisciplinary researchers and chiropractic clinicians from Switzerland presented a prospective study involving 148 patients with low back and leg pain. The study was published in the Journal of Manipulative and Physiological Therapeutics (29). The purpose of this study was to document outcomes of patients with confirmed, symptomatic lumbar disc herniations and sciatica that were treated with chiropractic side posture high-velocity, low-amplitude, spinal manipulation to the level of the disc herniation. Evaluations were performed at 2 weeks, 1 month, 3 months, 6 months, and 12 months. The authors make the following statements:
“The proportion of patients reporting clinically relevant improvement in this current study is surprisingly good, with nearly 70% of patients improved as early as 2 weeks after the start of treatment. By 3 months, this figure was up to 90.5% and then stabilized at 6 months and 1 year.”
“A large percentage of acute and importantly chronic lumbar disc herniation patients treated with chiropractic spinal manipulation reported clinically relevant improvement.”
“Even the chronic patients in this study, with the mean duration of their symptoms being over 450 days, reported significant improvement, although this takes slightly longer.”
“A large percentage of acute and importantly chronic lumbar disc herniation patients treated with high-velocity, low- amplitude side posture spinal manipulative therapy reported clinically relevant ‘improvement’ with no serious adverse events.”
“Spinal Manipulative therapy is a very safe and cost-effective option for treating symptomatic lumbar disc herniation.”
In America, it is not uncommon for persistent back pain to be treated surgically. An analysis of America’s low back surgery rate compared internationally to other nations was published in the journal Spine in 1994 (30). The authors were from the Department of Health Services, University of Washington in Seattle. They compared rates of back surgery in eleven developed countries to determine if back surgery rates are higher in the United States than in other developed countries. Their findings include:
“The rate of back surgery in the United States was at least 40% higher than in 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 orthopaedic and neurosurgeons in the country.”
In this regard, an interesting article was published in the journal Spine in 2013, designed to predict the major reason for back surgery as compared to the utilization of less invasive approaches (31). A team of investigators from Dartmouth Medical School, the University of Washington School of Medicine, and Ohio State University College of Public Health, completed a prospective cohort study to identify early predictors of lumbar spine surgery within 3 years after occupational back injury.
The authors note that back injuries are the most prevalent occupational injury in the United States, and that back pain is the most costly and prevalent occupational health condition among the U.S. workers. After adjustment for medical and general inflation, costs for occupational back pain increased over 65% from 1996 through 2002, and spine surgeries represent a significant proportion of these costs. Yet, they note:
“Spine surgeries are associated with little evidence for improved population outcomes, yet rates have increased dramatically since the 1990s.”
“Reducing unnecessary spine surgeries is important for improving patient safety and outcomes and reducing surgery complications and health care costs.”
Previous studies have shown that those with occupational back injuries who first saw a chiropractor had lower odds of chronic work disability, and that those seeing chiropractors for occupational back pain had “higher rates of satisfaction with back care.”
In this study, after controlling for injury severity, workers with an initial visit for the injury to a surgeon had almost nine times the odds of receiving lumbar spine surgery compared to those seeing primary care providers, and workers whose first visit was to a chiropractor had significantly lower odds of surgery (by 78%). The authors stated:
“42.7% of workers who first saw a surgeon had surgery, in contrast to only 1.5% of those who saw a chiropractor.”
“Approximately 43% of workers who saw a surgeon had surgery within 3 years, in contrast to only 1.5% of those who saw a chiropractor.”
“There was a very strong association between surgery and first provider seen for the injury, even after adjustment for other important variables.” [such as symptom severity]
“It is possible that these findings indicate that who you see is what you get.”
Seeing a chiropractor as the first provider for a back complaint significantly reduced odds of surgery.
These authors suggest that it is wise to use a “gatekeeper” for patients who suffer occupational back injury. This article presents substantial reason for why such a gatekeeper should be a chiropractor. The reduction of back surgeries in those consulting chiropractors for back pain represents a substantial costs savings, and also the highest levels of back care satisfaction.
- Foreman J; A Nation in Pain, Healing Our Biggest Health Problem; Oxford University Press, 2014.
www.ssa.gov (the Official Social Security Website): “December 2011, diseases of the musculoskeletal system and connective tissue were the primary reason disabled workers and disabled widow(er)s received benefits.”
- Associated Press; STEPHEN OHLEMACHER and RICARDO ALONSO-ZALDIVAR; July 22, 2015.
- Calabresi M; They’re the most powerful painkillers ever invented; And they’re creating the worst addiction crisis America has ever seen; The price of Relief; Why America can’t kick its painkiller problem; Time; June 15, 2015; pp. 26-33.
- Rommelmann N; The Great Opiate Boom; Wall Street Journal; June 6-7, 2915; p. C9.
- Szabo L; Heroin use surges among women, middle-class; USA Today; July 8, 2015; pp. A1.
- Wall Street Journal, October 7, 2013.
- Nachemson AL; The Lumbar Spine, an Orthopedic Challenge; Spine; Volume 1, Number 1, March 1976, pp. 59-71.
- Bogduk N, Tynan W, Wilson AS; The nerve supply to the human lumbar intervertebral discs; Journal of Anatomy; 1981; Vol. 132; No. 1; pp. 39-56.
- Mooney V; Where Is the Pain Coming From?; Spine; Vol. 12; No. 8; 1987; pp. 754-759.
- Kuslich S, Ulstrom C, Michael C; 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; Orthopedic Clinics of North America; Vol. 22; No. 2; April 1991; pp. 181-187.
- Ozawa T, Ohtori S, Inoue G, Aoki Y, Moriya H, Takahashi; The Degenerated Lumbar Intervertebral Disc is Innervated Primarily by Peptide-Containing Sensory Nerve Fibers in Humans; Spine Volume 31; Number 21; October 1, 2006; pp. 2418-2422.
- DePalma MJ, Ketchum JM, Saullo T; What is the source of chronic low back pain and does age play a role?; Pain Medicine; Feb 2011; Vol. 12; No. 2; pp. 224-233.
- Izzo R, Popolizio T, D’Aprile P, Muto M; Spine Pain; European Journal of Radiology; May 2015; Vol. 84; pp. 746–756.
- Ramsey RH; Conservative Treatment of Intervertebral Disk Lesions; American Academy of Orthopedic Surgeons, Instructional Course Lectures; Volume 11; 1954; pp. 118-120.
- Mathews JA and Yates DAH; Reduction of Lumbar Disc Prolapse by Manipulation; British Medical Journal; September 20, 1969; No. 3; 696-697.
- Edwards BC; Low back pain and pain resulting from lumbar spine conditions: a comparison of treatment results; Australian Journal of Physiotherapy; 15:104, 1969.
- White AA, Panjabi MM; Clinical Biomechanics of the Spine; Second edition; JB Lippincott Company; 1990.
- Turek S; Orthopaedics, Principles and Their Applications; JB Lippincott Company; 1977; page 1335.
- Kirkaldy-Willis WH, Cassidy JD; Spinal Manipulation in the Treatment of Low back Pain; Canadian Family Physician; March 1985; Vol. 31; pp. 535-540.
- Kuo PP and Loh ZC; Treatment of Lumbar Intervertebral Disc Protrusions by Manipulation; Clinical Orthopedics and Related Research; No. 215; February 1987; pp. 47-55.
- Quon JA, Cassidy JD, O’Connor SM, Kirkaldy-Willis WH; Lumbar intervertebral disc herniation: treatment by rotational manipulation; Journal of Manipulative and Physiological Therapeutics; 1989 Jun;12(3):220-7.
- Meade TW, Dyer S, Browne W, Townsend J, Frank OA; Low back pain of mechanical origin: Randomized comparison of chiropractic and hospital outpatient treatment; British Medical Journal; Volume 300; June 2, 1990; pp. 1431-7.
- Cassidy JD, Thiel HW, Kirkaldy-Willis WH; Side posture manipulation for lumbar intervertebral disk herniation; Journal of Manipulative and Physiological Therapeutics; February 1993;16(2):96-103.
- Stern PJ, Côté P, Cassidy JD; A series of consecutive cases of low back pain with radiating leg pain treated by chiropractors; Journal of Manipulative and Physiological Therapeutics; 1995 Jul-Aug;18(6):335-42.
- Giles LGF, Muller R; Chronic Spinal Pain: A Randomized Clinical Trial Comparing Medication, Acupuncture, and Spinal Manipulation; Spine July 15, 2003; 28(14):1490-1502.
- Muller R, Lynton G.F. Giles LGF, DC, PhD; Long-Term Follow-up of a Randomized Clinical Trial Assessing the Efficacy of Medication, Acupuncture, and Spinal Manipulation for Chronic Mechanical Spinal Pain
- Syndromes; Journal of Manipulative and Physiological Therapeutics January; 2005; Volume 28; No. 1.
- Santilli V, Beghi E, Finucci S; Chiropractic manipulation in the treatment of acute back pain and sciatica with disc protrusion: A randomized double-blind clinical trial of active and simulated spinal manipulations; The Spine Journal; March-April 2006; Vol. 6; No. 2; pp. 131–137.
- Leemann S, Peterson CK, Schmid C, Anklin B, Humphreys BK; Outcomes of Acute and Chronic Patients with Magnetic Resonance Imaging–Confirmed Symptomatic Lumbar Disc Herniations Receiving High-Velocity, Low Amplitude, Spinal Manipulative Therapy: A Prospective Observational Cohort Study With One-Year Follow-Up; Journal of Manipulative and Physiological Therapeutics; March/April 2014; Vol. 37; No. 3; pp. 155-163.
- Cherkin DC, Deyo RA, Loeser JD, Bush T, Waddell G; An international comparison of back surgery rates; Spine; June 1, 1994; Vol. 19; No. 11; pp. 1201-1206.
- Keeney BJ, Fulton-Kehoe D, Turner JA, Thomas M. Wickizer TM, Chan KC, Franklin GM; Early Predictors of Lumbar Spine Surgery after Occupational Back Injury: Results from a Prospective Study of Workers in Washington State; Spine; May 15, 2013; Vol. 38; No. 11; pp. 953-964.