A common cause of lateral deviation of the spine (scoliosis) is easily treated but can also be missed and misunderstood. Since other types of scoliosis are more worrisome and have a greater tendency to progress, the more common (and easily corrected) causes of spinal curvatures are often overlooked.
Common Types of Scoliosis
The term scoliosis describes "any lateral deviation of the spine from the midsagittal plane."1 There are many possible causes of a lateral curvature, and this condition can affect the cervical, thoracic or lumbar regions. The most common types of scoliosis seen by chiropractors can be divided into structural and functional categories.
Structural scoliosis: When a lateral deviation of the spine is fixed and doesn't correct during lateral bending, it is termed a structural scoliosis. While there are many disorders that can cause this condition, those most commonly seen are congenital (due to bony anomalies), neuromuscular (associated with various neuropathic and myopathic diseases) and idiopathic (the underlying cause is unknown). Unfortunately, most of these spinal curvatures do not respond well to conservative care and often require surgical consultation.
Functional scoliosis: The classification of functional scoliosis has been summarized by Panzer as compensatory (due to leg-length inequality or pelvic unleveling), postural (caused by habits and muscle imbalance) and transient (often an antalgic response to a disc herniation).2 The key factor in all of these conditions is the reversibility of the abnormal curvature with various positions and movements. In fact, this is the main method used to differentiate between structural and functional types of scoliosis.
Patient Evaluation and Examination
Adams forward-bending position: The quickest way to evaluate for a functional scoliosis is to have the patient perform the Adams position. In this test, the patient flexes forward from the waist with the arms hanging down and the hands together. If the spinal curvature straightens out and there is no evidence of rib humping, then the test is negative, which indicates a functional scoliosis.3
Postural assessment: The first step in examining a patient with a scoliosis is to carefully inspect the alignment of the entire body during relaxed, upright stance. Head position in relation to the body, relative heights of the shoulders and pelvis, and any spinal list or rotations should be noted since corrective exercises may be needed. The lower extremities must also be evaluated for asymmetry, since functional scolioses are frequently associated with leg-length inequality.4 Excessive pronation of one or both of the feet is commonly seen.
Hyperpronation: The loss of arch height that occurs with excessive pronation allows the pelvis to drop to the more pronated side during stance and gait.5 The resulting lateral pelvic tilt lowers the sacral base and drops the lowest freely moveable vertebra to the side of the shorter leg. A lateral spinal curvature develops in the lumbar spine due to lack of balanced support from the lower extremities with every step. In response, various compensatory pelvic lists and sacroiliac subluxation complexes develop.6
Researchers have also verified that a posterior rotation of the innominate bone often develops on the side of a longer leg.7 If the functional curvature progresses to involve the thoracic region, there may be a mild rib hump that disappears upon correction of the leg discrepancy.8
Corrective Procedures
Lower extremity support: Functional scoliosis with leg-length discrepancy due to a low medial arch and excessive pronation is easily treated with the use of custom-made stabilizing orthotics to reduce pronation. This provides substantial correction for most short legs and often avoids the need for a heel lift. Some patients will need a permanent heel lift due to an anatomical difference in leg growth.
Muscle imbalances: Functional scoliosis often causes chronic muscular strain, most commonly seen as myofascial trigger points in the quadratus lumborum, but also in the psoas and external abdominal oblique muscles.9 Therefore, manual muscle treatments, stretching and even spinal-strengthening exercises may be necessary to obtain rapid, complete resolution of symptoms. These muscle imbalances can become perpetuating factors if the underlying foot and leg asymmetries are not corrected.
Spinal adjustments: It is very important to assess and adjust the pelvis and spine as each patient adapts to wearing the corrective orthotics. Since excessive pronation places abnormal stress in predictable areas (primarily the sacroiliac joints and lumbar vertebrae), close evaluation of these regions is warranted. Because functional scoliosis interferes with postural alignment, the entire spine must be checked and adjusted frequently during the initial adaptation period. In fact, the upper cervical region is often quite slow in adapting to the change in spinal and pelvic posture, and needs to be evaluated regularly and adjusted as needed.
Healthy Spines Require Healthy Feet
When a lateral curvature of the spine that reduces during forward bending is found, a functional scoliosis has been identified and conservative treatment is indicated. A careful postural evaluation will usually discover an asymmetry in the lower extremities, with poor support for the pelvis. The combination of custom-made orthotic stabilizer support and chiropractic adjustments is often very effective in treating these functional scolioses, much to the relief of the patient and concerned family members.
References
- Yochum TR, Rowe LJ. Essentials of Skeletal Radiology, 3rd Ed. Baltimore: Lippincott Williams & Wilkins, 2005:405.
- Panzer DM, Gatterman MI, Hyland J. Postural Complex. In: Gatterman MI, ed. Chiropractic Management of Spine-Related Disorders. Baltimore: Lippincott Williams & Wilkins, 2004:312.
- Evans RC. Illustrated Essentials in Orthopedic Physical Assessment. St. Louis: Mosby-Yearbook, 1994:219.
- Plaugher G. Textbook of Clinical Chiropractic: A Specific Biomechanical Approach. Baltimore: Williams & Wilkins, 1993:266.
- Hammer WI. Hyperpronation: causes and effects. Chiro Sports Med, 1992; 6:97-101.
- Rothbart BA, Estabrook L. Excessive pronation: a major biomechanical determinant in the development of chondromalacia and pelvic lists. J Manip Physiol Ther 1988; 11:373-9.
- Cummings G, Scholz JP, Barnes K. The effect of imposed leg length difference on pelvic bone symmetry. Spine 1993;18:368-73.
- Magee DJ. Orthopedic Physical Assessment. Philadelphia: WB Saunders, 1987:397.
- Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Lower Extremities. Baltimore: Williams & Wilkins, 1992:63.
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