Scoliosis This section was compiled by Frank M. Painter, D.C.
Send all comments or additions to: Frankp@chiro.org
FROM: Physical Diagnosis: Procedures and Methodology in Chiropractic Practice
Chapter 17 ~ Physical Examination of the Lungs and Thorax
By Richard C. Schafer, D.C., FICC
The complex subject of scoliosis is briefly described in this chapter because its gross manifestations occur in the thoracic area. It should be readily recognized, however, that spinal curvatures sometimes find their primary cause in the lower extremities, pelvis, lumbar region, or cervical spine.
Rib Distortion
Spinal rotation in scoliosis occurs posteriorly on the side of convexity of the curve and anteriorly on the side of concavity. This is manifested by rib cage deformity (hump) in the thoracic area and bulging erector spinae in the lumbar area. The intercostal spaces are vertically stretched on the side of convexity and narrowed on the side of concavity. The normal contour of the entire thorax is distorted, taking on an oblique configuration rather than a relatively ovoid shape when viewed from above. This is produced so that the shoulders and head can be oriented forward the effect of a biological mandate rather than a biomechanical need.
Rib hump is readily observed in the Adams position and can be measured by various methods. Ribs do not distort by themselves; the distortion is essentially the result of vertebral rotation coupled with tilting. Thus, rib distortion offers an indirect measurement of spinal rotation.
In measuring in vivo rib cage distortion transverse to the apical vertebra, the examiner may apply the simple carpenter's instrument used for measuring curved surfaces to which a small line level has been fixed (Fig. 17.6). As the points of the instrument are quite sharp, a thin sheet of pliable plastic should be placed on the patient's back. This sheet should be thick enough to protect the patient's skin, yet thin enough to conform exactly to the curvature present. The instrument is applied to the patient, then the curve formed is traced on a sheet of paper and made part of the patient's progress record. This method may be used in both the prone and Adams positions if desired. It can be used on any region of the spine and on extremity joints to record progressive changes in skin configuration (eg, swelling reduction, rib posture changes).
Scoliosis
The term scoliosis refers to any combination of lateral curvature from a straight line with twisting of the spine when viewed from the front or the back. What is grossly viewed in the typical scoliosis from the posterior are the typical spinal curves normally seen from the lateral. That is, the curves are situated in the wrong plane, frontal rather than sagittal, and the vertical axis rotation is usually in the wrong direction and often exaggerated. Simply, it is often as if the spine were fixed in space and the head and pelvis were rotated +/- several degrees in the same direction (refer to Fig. 1.6). Thus, the majority of the distortion seen in scoliosis is the result of rotation (Fig. 17.60). This is the gross effect of scoliosis. The segmental effect is abnormal focal motion-unit disrelationship where normal rotation, lateral tilting, and A-P facet slip has become fixed, functionally and/or structurally. Scoliosis is a mechanical disorder when gross, but there are always many biologic influences operating as well as purely mechanical forces.General Considerations. When a postural distortion is recognized, several clinical questions arise. For example, how severe is the distortion? Is it affecting function? Is the distortion stabilized or progressing? What was the initial cause or causes: congenital, pathologic, acquired, or a combination of factors? Can it be corrected? If so, how? How much correction can be expected? How long will it take? How much patient cooperation will be necessary?
The first step in answering these questions is a thorough physical examination. In slight or doubtful cases, the tips of the spinous processes should be marked with a marking pencil which makes the deviation more readily visible. It is assumed here that the postural analysis will follow a complete case history and standard physical, neurologic, and orthopedic examinations. Joint motion, muscle strength, sensory perception, and reflexes must be thoroughly evaluated.
Terminology. A great variety of terms are used in describing the various types of spinal distortion. In each case, however, scoliosis is described as if viewed from the posterior and exaggerated A-P curves are described as if seen from the side. See Table 17.12.
Scoliosis can be classified from a structural, functional, or clinical view point. In each classification, there is considerable overlapping and no single classification offers answers to all questions. However, we will briefly mention these so that a better appreciation can be developed.
Structural Classification of Scoliosis
The various forms of scoliosis can be grouped into two major types (structural and nonstructural), and each has its subdivisions according to its major etiology.Nonstructural Scoliosis. A nonstructural scoliosis is the effect of gravitational forces and muscles and ligaments of asymmetrical integrity. It will straighten by voluntary effort or in the non-weight-bearing positions. Non-structural (functional) scolioses are not usually as progressive as structural scolioses. They can be of the postural, compensatory, or transient type. Postural scoliosis curves are slight, disappear in the Adams and recumbent positions, and usually are first noticed at about 12 years of age. Compensatory scoliosis is the typical result of a leg length defect where the pelvis dips down on the short side. Transient structural scoliosis may be of the sciatic, hysterical, or inflammatory type. Sciatic scoliosis is not a true scoliosis, but rather a functional antalgic adaptation to pain caused by nerve root pressure or irritation. Hysterical scoliosis, most rare, is a manifestation of organ language of psychic origin. Inflammatory scoliosis is the result of such processes as a perinephric (eg, psoas) abscess.
Structural Scoliosis. A structural scoliosis will not straighten with voluntary effort in a non-weight-bearing position. It is quite rigid and the result of osseous deformation or fixated soft-tissue changes of related discs, ligaments, muscles, and joint capsules. Structural scoliosis may be of the idiopathic, congenital (Fig. 17.61), neuromuscular, neurofibromatotic, mesenchymal, or traumatic type. Its most common overt sign is a lack of adequate compensatory secondary curvatures; that is, decompensation, where the head and neck are lateral to the base of support when viewed from the front or back.
There are two major types of structural curves:
Irreversible structural curves that exhibit gross structural asymmetry and/or anomalies. Deformation can be exhibited between, within, and/or around involved vertebrae. When this occurs, there are two problems: (a) the spinal curves are "out of plane" and (b) there is vertebral motion-unit deformation. The immediate structural defect may be osseous, in the soft tissues, or both.
Structural curves that are the result of possible reversible connective tissue changes such as ligament shortening or chronic muscular hypertonicity. This type is usually the first stage of the first type. It is not unusual for a curve to exhibit some degree of functional reduction but not complete reduction; that is, it may be both functional and structural.
Features: Certain generalities can be drawn bilaterally as scoliosis progresses:
On the side of concavity, the vertebral bodies rotate anteriorly, the ribs are closer together and projected backward, the intercostal spaces are reduced and the soft tissues are thickened and contracted, the disc spaces are thinned (wedged) and the nucleus shifts toward the opposite side, the vertebral pedicles and laminae shorten and thicken, the flank rib ilium distance is reduced, and the intrathoracic organs become compressed.
On the side of convexity, the vertebral bodies rotate posteriorly, the ribs are further apart and projected anteriorly, the intercostal spaces are widened and the soft tissues are stretched, the disc spaces are widened, the vertebral canal becomes narrowed, the flank rib ilium distance is increased, and the intrathoracic viscera become stretched.
Clinical Classification of Scoliosis
A more detailed classification of spinal distortions is appropriate for many clinicians. One is offered in Table 17.13 that is a composite that has been adapted from the data of several authorities.
Associated Pulmonary Impairment. Maximum breathing capacity is considered to be reduced in proportion to the degree of thoracic scoliosis present. According to Gucker's studies, gross rotary deformity appears to affect cardiopulmonary function to a greater extent than gross lateral deformity. Pulmonary impairment is not usually a priority concern unless the deformed rigid thoracic cage reaches a point that restricts the pulmonary volume and vital capacity adequate for the demand. This is not to say that restriction far below this threshold will not predispose the patient to numerous cardiorespiratory disorders even though there are no signs of obstructive pulmonary disease. As the spinal deformity increases, the heart is pushed inferior and traction is placed on its superior nerves and vessels. See Figure 17.62.
Arterial restriction in the lung fields leads to right ventricular hypertrophy. While the effects may be perceived by cardiac auscultation, its cause is almost impossible to detect on roentgenography. Cardiorespiratory failure is so slow in these cases that the distortion and its neuromuscular and neurovascular causes are rarely given the credit they deserve.
The reduced vital capacity in spinal deformity may not be due solely to mechanical restriction inasmuch as weakened thoracic and possibly abdominal muscles, costal fixations, thoracic venous and lymph flow restrictions, and portal pooling are invariably involved in scoliosis. Most of these nonmechanical influences can be attributed to subtle secondary sympathicotonia.
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