A Review of Concepts and Evidence
Manipulation of the joints of the lumbar spine usually involves some degree of segmental rotation. Historically, lumbar spine manipulations that are primarily rotational in nature are discouraged because it is assumed that such maneuvers are associated with an increased risk of injury to the annulus of the intervertebral disc. Such an annular disc injury would increase the risk for disc herniation and compressive neuropathy (radiculopathy), a problem that may require a surgical management.
The traditional caution pertaining to rotational manipulations to the low back is based upon an understanding of the anatomy of the annulus of the disc. The collagen fibers that comprise the annulus of the disc are arranged in layers, and each layer is crossed in opposite directions.
During disc rotational movements, half of the annular collagen fibers become tense, and the other half become lax. Therefore it is argued that rotational stress applied to the annulus of the disc is resisted by only half of the annular collagen fibers, the half that become tense. It is argued that the disc is operating at only half strength during rotationally applied stress, increasing its vulnerability to injury, herniation, compressive radiculopathy and surgical intervention.
Despite these arguments, there is evidence that the lumbar disc cannot be injured by rotational manipulations, and that rotational manipulations are safe when applied by an appropriately trained provider.
In 1981, a study was published in the journal Spine, titled (1):
The Relevance of Torsion to the
Mechanical Derangement of the Lumbar Spine
The authors of this study observed the mechanics of applied rotational stresses that were applied to the lumbar spine discs of cadavers. They noted that the limit of lumbar spinal segmental rotation was not created by the disc, but rather by the facet joint. During rotational stress, the compression facet is the first structure to yield at the limit of torsion, and this occurs after about 1-2° of rotation. The authors state:
“Much greater angles are required to damage the intervertebral disc, so torsion seems unimportant in the etiology of disc degeneration and prolapse.”
“Because of the protection offered by the compression facet, the intervertebral disc is subjected to relatively small stresses and strains in the physiologic range of torsion. By the time the facets are damaged, the disc is rotated only about one-third to one-tenth of its maximum angle and is bearing a small fraction of the torque required to rupture it.”
“Except in cases of extreme trauma and as a sequel to crushing of the apophyseal joints, axial rotation can play no major part in the mechanical derangement of the intervertebral disc in life.”
Two years later, in 1983, the same group published an updated cadaver studies in journal Spine, titled (2):
The Mechanical Function of the Lumbar Apophyseal Joints
Based upon their experiments, the authors concluded that the facet joints “prevent excessive movement from damaging the discs: the posterior annulus is protected in torsion by the facet surfaces and in flexion by the capsular ligaments.” They note that the facets only allow at most 2° of rotation, and also note that the disc will completely recover from all rotational stresses that are less then 3°. The authors state:
“In flexion, as in torsion, the apophyseal joints protect the intervertebral disc.”
“The function of the lumbar apophyseal joints is to allow limited movement between vertebrae and to protect the discs from shear forces, excessive flexion, and axial rotation.”
In 1995, a third updated article was published by this group and published in the journal Clinical Biomechanics, titled (3):
Recent Advances in Lumbar Spinal Mechanics
and their Clinical Significance
Once again, these authors note that rotational loading of the lumbar spinal motor unit will always damage the facet joints “long before the disc.” If the facet joints are removed, rotational forces will damage the disc if subjected to rotational loads between 10-20°.
Despite the supposition that lumbar spinal manipulation, and especially primary rotational manipulation, may injure the intervertebral disc, these cadaver biomechanical studies indicate that such injuries are not biomechanically possible.
Can Rotational Manipulation Help Patients
with Proven Lumbar Disc Herniation?
There is evidence that lumbar spine rotational manipulations are effective in the treatment of low back pain, including the management of disc herniation.
In 1954, there was a study in the Instructional Course Lectures of the American Academy of Orthopedic Surgeons, titled (4):
Conservative Treatment of Intervertebral Disk Lesions
The author advocates the use of conservative treatment, including spinal manipulation, for patients suffering with low back disc herniations. He 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.”
“We limit the use of manipulation almost entirely to those patients who do not seem to be responding well to non-manipulative conservative treatment and who are anxious to have something else done short of operative intervention.”
“The patient lies on his side on the edge of the table facing the surgeon and the leg that is up is allowed to drop over the side of the table, tending to swing the up-side of the pelvis forward. The arm that is up is allowed to drop back behind the patient, tending to pull the shoulder back. The surgeon then places one hand on the patient’s shoulder and his opposite forearm on the patient’s iliac crest. Simultaneously, the shoulder is thrust suddenly back, rotating the torso in one direction while the iliac crest is thrust down and forward, rotating the pelvis in the opposite direction. This gives the lumbar spine a twist that frequently causes an audible and palpable crunch. This procedure is then repeated with the patient on his other side. The patient is then turned on his back and his hips and knees are hyperflexed sufficiently to forcibly flex the lumbar spine which tends to open up the disk spaces posteriorly.”
The manipulation described here is rotational in nature, using the term “twist.”
In 1969, a study was published in the British Medical Journal, titled (5):
Reduction of Lumbar Disc Prolapse by Manipulation
These authors evaluated a number of patients that presented with an acute onset of low back and buttock pain that 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 treated with long-lever rotation manipulations of the lumbar spine, using the shoulder and iliac crest as levers. These lumbar spine manipulations were clearly accompanied with a thrust maneuver. 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. The authors state:
“Manipulation of the lumbar spine has been used as an empirical treatment of low backache since antiquity. The persistence and popularity of this type of treatment was based on the clinical impression that it is beneficial.”
“The lumbar spine was rotated away from the painful side to the limit of its range, the buttock or thigh of the painful side being used as a lever; a firm additional thrust was made in the same direction. This manoeuver was repeated until abnormal symptoms and signs had disappeared, progress being assessed by repeated examination.”
“Rotation manipulations apply torsion stress throughout the lumbar spine. If the posterior longitudinal ligament and the annulus fibrosus are intact, some of this torsion force would tend to exert a centripetal force, reducing prolapsed or bulging disc material.”
“The results of this study suggest that small disc protrusions were present in patients presenting with lumbago and that the protrusions were diminished in size when their symptoms had been relieved by manipulations.”
These authors concluded “it seems likely that the reduction effect [of the disc protrusion] is due to the manipulating thrust used.”
This article clearly describes the manipulations used as “forceful,” “thrust,” and “rotation.” Their explanation for the successful treatment was credited to a reduction in the size of the disc protrusion from the rotational component of the manipulation: rotation tightens up intact aspects of the annular ring, pulling the nuclear protrusion towards the center and away from the nervous system.
Another study was published in 1969 in the Australian Journal of Physiotherapy, titled (6):
Low Back Pain and Pain Resulting from Lumbar Spine Conditions:
A Comparison of Treatment Results
The author 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. His results were clearly summarized in White and Panjabi’s Clinical Biomechanics of the Spine, in 1990. Drs. White and Panjabi state (7):
“A well-designed, well executed, and well-analyzed study.”
In the group with central low back pain only, “the results were acceptable in 83% for both treatments. However, they were achieved with spinal manipulation using about one-half the number of treatments that were needed for heat, massage, and exercise.”
In the group with pain radiating into the buttock, “the results were slightly better with manipulation, and again they were achieved with about half as many treatments.”
In the groups with pain radiation to the knee and/or to the foot, “the manipulation therapy was statistically significantly better,” and in the group with pain radiating to the foot, “the manipulative therapy is significantly better.”
“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.”
It is usual for pain that travels further down an extremity to be associated with greater compression, or a larger disc protrusion. In this study, manipulation worked excellently in patients with leg pain radiation.
In 1977, the third edition of Orthopaedics, Principles and Their Applications was published. The author, Samuel Turek, MD (d. 1986), was a Clinical Professor, Department of Orthopedics and Rehabilitation at the University of Miami School of Medicine. His text encompasses 1,574 pages. In the section pertaining to the protruded disc, Dr. Turek states (8):
Treatment of Intervertebral Disc Herniation With Manipulation
“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.”
The manipulation maneuver described by Dr. Turek is the classic description of the rotational manipulation of the lumbar spine. His comments are in the aspect of his book pertaining to the treatment of the protruded lumbar intervertebral disc.
In February 1987, a study was published in the journal Clinical Orthopedics and Related Research, titled (9):
Treatment of Lumbar Intervertebral Disc Protrusions by Manipulation
In this study, the authors 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. The manipulation was described as follows:
“The patient is placed on the sound side first with the hip and knee of the painful side flexed and the sound side straight. The operator rests one hand in front of the shoulder and the other hand on the buttock. By simultaneously pulling the shoulder backwards and pushing the buttock forwards, a snap or click can usually be heard or felt. This manipulation may then be repeated on the other side as required.”
The authors state:
“Manipulation of the spine can be effective treatment for lumbar disc protrusions.” “Most protruded discs may be manipulated.”
“Manipulation usually begins with preparatory movements of the vertebral joints to their extreme and then rotation is carried out.”
“During manipulation a snap may accompany rotation. Subjectively it has dramatic influence on both patient and operator and is thought to be a sign of relief.”
“If derangement of the facets or subluxation of the posterior elements near the protruded disc occurs, the rotation may have caused reduction, giving remarkable relief.”
“Gapping of the disc on bending and rotation may create a condition favorable for the possible reentry of the protruded disc into the intervertebral cavity, or the rotary manipulation may cause the protruded disc to shift away from pressing on the nerve root.”
These authors stress that rotation is the most critical component of the manipulation to enhance successful outcome.
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 (10). 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 1993, a “Review Of The Literature” article was published and titled (11):
Side Posture Manipulation for Lumbar Intervertebral Disk Herniation
These authors were from the Department of Orthopaedics, Royal University Hospital, Saskatoon, Saskatchewan, Canada. 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, a study was published and titled (12):
A Series of Consecutive Cases of Low Back Pain
with Radiating Leg Pain Treated by Chiropractors
The authors 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. The authors 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 2006, a study was published in The Spine Journal, titled (13):
Chiropractic Manipulation in the Treatment of Acute Back Pain
and Sciatica with Disc Protrusion
The purpose of this study was to assess the short- and long-term effects of spinal manipulations on acute back pain and sciatica with disc protrusion. It is a randomized double-blind trial that used 102 patients.
The authors noted the following observations:
“Active manipulations have more effect than simulated manipulations on pain relief for acute back pain and sciatica with disc protrusion.”
“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.”
The authors concluded that chiropractic spinal “manipulations may relieve acute back pain and sciatica with disc protrusion.”
In 2014, a group of multidisciplinary researchers and chiropractic clinicians 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 and titled (14):
Outcomes of Acute and Chronic Patients with
Magnetic Resonance Imaging–Confirmed Symptomatic Lumbar Disc Herniations
Receiving High-Velocity, Low-Amplitude, Spinal Manipulative Therapy
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 at the level of the disc herniation. 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 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.”
This study shows that patients with proven lumbar intervertebral disc herniation and compressive neuropathology that receive traditional chiropractic side-posture manipulation is both safe and effective. The ultimate clinical effectiveness of about 90% is impressive when compared to any form of therapy, and with no reported serious side effects.
What is the Best Evidence Assessing the Safety of
Spinal Manipulation as Related to Lumbar Disc Herniation?
In July 2018, a team of Canadian researchers from multiple universities and health care facilities published an article on this topic in the European Spine Journal, titled (15)
Chiropractic Care and Risk for Acute Lumbar Disc Herniation:
A Population-based Self-controlled Case Series Study
This study is important and impressive. The objective was to investigate the association between chiropractic care and acute lumbar disc herniation and contrast this with the association between primary care physician care and acute lumbar disc herniation. The authors note that:
“To date, no valid epidemiologic assessment of the risk for acute disc herniation following chiropractic treatment is available in the scientific literature.”
“This study is the first population-based epidemiologic investigation of the association between chiropractic care and acute lumbar disc herniation.”
This most impressive aspect of this study is that the study population included the entire population registered in Ontario’s provincial healthcare system over an 11-year period, representing over 100 million person-years of observation. The authors were able to identify all surgically managed cases of acute lumbar disc herniation, visits to chiropractors and to primary care providers.
The full understanding of this study requires a discussion of protopathic bias:
Protopathic bias is when a treatment for the first symptoms of a disease appear to cause or accelerate a deteriorating outcome, when, in fact, the disease process was following a natural progression, and the treatment intervention had nothing to do with the deteriorating outcome. It is a potential bias when there is a lag time from the first symptoms and start of treatment before actual diagnosis is understood or determined.
One of the most recognizable initial presentations of lumbar disc herniation is low back pain without leg pain or extremity findings. This initial symptom of back pain commonly precedes extremity symptoms/signs and eventually a lumbar disc herniation diagnosis confirmed. Many patients initially present with low back pain alone, which “then progresses to radicular leg pain with or without neurologic signs.”
Symptomatic lumbar disc herniation tends to follow this course:
- Individuals in the early phase of a symptomatic lumbar disc herniation often complain only of low back pain.
- As the condition naturally progresses, most patients will develop sciatica/leg symptoms/signs.
- At different points in time along this course, these patients may seek healthcare for assessment and intervention.
These authors state:
“If chiropractic treatment occurs before a lumbar disc herniation progresses to radiculopathy or neurologic deficit and is thus diagnosed, then the [chiropractic] treatment itself can be erroneously blamed for causing the lumbar disc herniation.”
“This systematic error—known as protopathic bias—is a type of reverse-causality bias due to processes that occur before a diagnosed or measured outcome event.”
“Given that deteriorating outcome can initially present as low back pain, it is possible that these patients seek chiropractic care in the prodromal phase of deteriorating outcome, implying that an observed association between chiropractic care and acute deteriorating outcome may not be causal.”
“Since patients also commonly see primary care physicians for back pain and this healthcare encounter is unlikely to cause disc herniation, an observed association between PCP visits and acute deteriorating outcome could be attributed to care seeking for the initial symptoms of deteriorating outcome (protopathic bias).”
“The risk for acute lumbar disc herniation with early surgery associated with chiropractic visits was no higher than the risk associated with primary care physician visits.”
“Our analysis suggests that patients with prodromal back pain from a developing disc herniation likely seek healthcare from both chiropractors and primary care physicians before full clinical expression of acute lumbar disc herniation.”
“We found no evidence of excess risk for acute lumbar disc herniation with early surgery associated with chiropractic compared with primary medical care.”
The analysis “suggested a positive safety profile for chiropractic care relative to the baseline risk represented by primary care physician care.”
This study presents the best evidence to date that chiropractic spinal adjusting does not increase the risk or incidence of lumbar disc herniation.
The information presented here supports these points:
- Rotational manipulation cannot injure the intervertebral disc.
- Chiropractic rotational manipulation is often effective treatment for lumbar disc herniation.
- Evidence concludes that chiropractic rotational manipulation does not herniate the lumbar disc.
- Adams MA, Hutton WC; The Relevance of Torsion to the Mechanical Derangement of the Lumbar Spine; Spine; Vol. 6, No. 3; May/June 1981; pp. 241-248.
- Adams MA, Hutton WC; The Mechanical Function of the Lumbar Apophyseal Joints; Spine; Vol. 8; No. 3; April 1983; pp. 327-330.
- Adams MA, Dolan P; Recent advances in lumbar spinal mechanics and their clinical significance; Clinical Biomechanics; Vol. 10; No. 1; 1995; pp. 3-19.
- Ramsey RH; Conservative Treatment of Intervertebral Disk Lesions; American Academy of Orthopedic Surgeons, Instructional Course Lectures; Volume 11; 1954; pp. 118-120.
- Mathews JA, Yates DAH; Reduction of Lumbar Disc Prolapse by Manipulation; British Medical Journal; September 20, 1969; No. 3; pp. 696-697.
- Edwards BC; Low back pain and pain resulting from lumbar spine conditions: a comparison of treatment results; Australian Journal of Physiotherapy; Vol. 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.
- Kuo PP, 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; June 1989; Vol. 12; No. 3; pp. 220-227.
- Cassidy JD, Thiel HW, Kirkaldy-Willis WH; Side posture manipulation for lumbar intervertebral disk herniation; Journal of Manipulative and Physiological Therapeutics; February 1993; Vol. 16; No. 2; pp. 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; Vol. 18; No, 6; pp. 335-342.
- 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.
- Hincapié CA, Tomlinson GA, Côté P, Rampersaud YR, Jadad AJ, Cassidy JD; Chiropractic Care and Risk for Acute Lumbar Disc Herniation: A Population-based Self-controlled Case Series Study; European Spine Journal; July 2018; Vol. 27; No. 7; pp. 1526–153.