As we all know, occasionally a patient will present with acute-onset low back pain with or without a precipitating incident. A distinguishing feature of the presentation is visible lateral antalgia, both standing and walking.
Acute locked-back syndrome may have multiple underlying biomechanical and musculoskeletal root causes, including muscle spasm of the quadratus lumborum, unilateral facet imbrication with fixation of the lower lumbar and lumbosacral zygapophyseal joints, and rotational misalignment of one or more lumbar vertebrae relative to the subjacent segment. Let's consider the last of these findings as we evaluate and treat the patient.
Exam Findings
Examination findings for the patient with locked back attributable to lumbar rotational misalignment include some or all of the following:
- Taut and tender fibers over the inferior articular process and zygapophyseal joint of the involved segment (usually L4)
- Edema and sudoriferous changes in the periarticular soft tissue around the facet joint
- Apprehension and reproduction of pain symptoms when the patient attempts lumbar lateral bending to the side opposite antalgia
- Palpable hypertonicity of superficial and deep paraspinal musculature, particularly with application of digital pressure
- Localized pain, frequently radiating to the buttock and posterior thigh on rotation and extension on the side of involvement (Kemp's test)
- Elevated cutaneous skin temperature over the symptomatic region – detectable by thermal instrumentation and even by manual contact
- Flank pain and muscle hypertonicity or spasm in the quadratus lumborum on the side of involvement, with active trigger points along the iliac crest and the inferior rib
Note: Be sure to rule out an active pathology such as a urinary tract infection, which may also present with flank pain, muscle boarding and splinting in the lumbar soft tissues of the back.
What's the Cause? Theories to Consider
Several theoretical models of acute locked-back syndrome have been suggested. Exelby discusses three "theoretical proposals of acute locked back,"1 any or all of which provide the clinician with a starting point for assessing the patient. These models involve facet or discal entrapment and proprioceptive responses of tonically contractured deep paraspinal muscles.
Facet entrapment, suggests Exelby, involves buckling of articular soft tissue into the subcapsular space, creating a "space occupying lesion under the capsule."2 As a result, movement of the spine, especially into extension and rotation, is severely pain limited.
With discal entrapment, Exelby's model implicates displacement of nuclear material into radial fissures of a deteriorating disc on flexion, such that extension or even attempting to return to an upright position provokes a painful response.2
The discal entrapment theory is consistent with Earhart's observation that in the long term the patient is at extreme risk of a full disc prolapse at the level of involvement.3
The third underlying cause of locked-back syndrome, the proprioceptive hypothesis, argues for shortened or contractured trunk flexors that reflexively shorten further into spasm, with attempts to return the trunk to the neutral, upright position.4
In our own literature, from a time prior to the rewarding expansion of the published chiropractic discourse community, the work of one clinician and lecturer can be useful for understanding the locked-back phenomenon. In his self-published text, Tortipelvis, Fred Barge discusses radiographic and clinical findings that can be useful. Hugh B. Logan, founder of Logan Biomechanics, also notes the clinical impact of vertebral rotation resulting in "nerve pain" and restricted range of motion in the lumbar region.5
Barge suggests acute locked-back syndrome is a form of tortipelvis, a term he coined. He describes acute lateral tortipelvis as an X-ray finding in the A-P lumbopelvic view in which there is "lumbar body rotation to the closed wedge side with stacking above."6
Readers familiar with the Gonstead analysis will recognize lateral tortipelvis as either a PLS-M (body right, closed wedge right) or PRS-M (body left, closed wedge left) listing, typically confined to the fifth lumbar vertebra.
Barge also observed that lateral tortipelvis was most likely to be discovered at the level of L4 (70 percent) and less frequently at L3 (15 percent) and L5 (10 percent).
Logan holds the position that most inferior lumbar vertebrae, typically L5, demonstrate body rotation to the side of sacral inferiority, resulting in a normal, compensatory lumbar scoliosis on the side of sacral inferiority.5 So far, the best explanation we have for what happens when the L4 body demonstrates relative rotation to the closed-wedge side above L5 is that the curve convexity shifts to the side of L4 body rotation.
The net result, though, is the reversal of the lateral lumbar curve results in stacking and fixation on the side of L4 body rotation. Consequently, the patient shows the classic signs of locked-back syndrome – pain and the inability to straighten up away from the side of stacking.
Adjusting the Patient With Locked-Back Syndrome
The core event in adjusting the involved segment in locked-back syndrome is to apply an inferior to superior (I-S) thrust on the inferior articular process on the side of involvement to open the closed or narrowed wedge of the involved segment. Radiographic findings may be useful for determining the precise level of inferiority, but static palpation to elicit point tenderness is still a reliable method of finding the subluxation.
The best correction outcome is likely to occur by using the pelvic drop piece of a hi-lo table. There may be several possible ways to adjust the patient with locked-back syndrome. Following is a method which directly addresses the closed wedge.
To adjust the involved segment, take a modified scissor stance (facing the scapula on the opposite side of the side of involvement.) Use the thumb of the superior hand to take a firm I-S tissue pull until the ball of the thumb is snugged up firmly against the inferior articular process of the segment to be adjusted.
Keep in mind that the subcutaneous and paraspinal muscles can be rigidly contractured with locked-back syndrome, and it will require diligence to locate the best segmental contact point.
Place the fleshy pisiform of the inferior hand over the nail of the thumb contact. Apply a brisk P-A and I-S thrust into the inferior articular process, using enough force to trigger release of the drop mechanism with the intent of driving the process up the inclined plane of the facet. Keep in mind that lumbar facets are typically oriented sagittally, so the P-A component of the thrust is the main operator.
Because paraspinal muscles and periarticular soft tissue are likely to be distressed, warn the patient that the adjustment could cause transient irritation. Post-checks immediately following the adjustment may yield little useful information. Assessment of the outcome of care is best conducted with a follow-up visit.
References
- Excelby L. The locked lumbar facet joint: intervention using mobilizations with movement. Manual Therapy, 2001;6(2):116-121.
- Bogduk N, Jull G. The theoretical pathology of acute locked back: a basis for manipulative therapy. Manual Medicine, 1985;1:78-82.
- Earhardt X-ray seminar series, St. Louis, Mo., 1976.
- Chaitow L. Positional Release Techniques. Edinburgh: Churchill-Livingstone, 1998: p. 10.
- Barge FH. Tortipelvis: The Slipped Disc Syndrome – Its Cause and Correction. La Crosse, Wisc.: Barge Chiropractic Clinic, 1982.
- Logan HB. Logan Basic Methods. St. Louis: Vinton F. Logan & Fern M. Murray, 1950.
Dr. Howard Pettersson, a 1976 graduate of Logan College of Chiropractic, is an associate professor of technique at Palmer College of Chiropractic. He was the senior editor of Activator Methods Chiropractic Technique – College Edition, published in 1989, and published Pelvic Drop Table Adjusting Technique in 1999. His most recent publication, written with Dr. Green, is How to Find a Subluxation, published in 2003.
Dr. J.R. Green is a 1988 Graduate of Palmer College of Chiropractic. He retired from the Palmer faculty after many years of teaching basic sciences and chiropractic technique. He is currently in private practice in Galva, Ill., and is also an adjunct professor of chemistry with the Eastern Iowa Community College District. Dr. Green was one of the writers of Activator Methods Chiropractic Technique (1997) and also worked as a technical writing consultant on Activator Methods Chiropractic Technique – College Edition and Pelvic Drop Table Adjusting Technique.