THE CERVICAL SPINAL STENOSIS CONTROVERSY - 09/09/11
Resumen |
Just as is true of other neurologic conditions, such as concussions, the world's literature on spinal stenosis is confused by a multiplicity of definitions. This renders extremely difficult, if not impossible, a comparison of different articles because identical structural entities are not being compared, for example, apples are being compared with oranges or pears, not just apples.
The purpose of this article is to define cervical spinal stenosis in terms of the 1990s imaging technology, the MR image, and based on the experience of the National Center for Catastrophic Sport Injury Research, give clear indications for sports participation once this condition has produced symptoms.
In a study of 200 randomly selected asymptomatic subjects who underwent lateral cervical spine radiograph examinations at a fixed target distance of 72 inches, Wolfe and associates17 in 1956, established the normal values of the sagittal diameters of the cervical spine. Canal height, sagittal diameter, was defined as the anteroposterior diameter measured from the posterior aspect of the vertebral body to the most anterior point on the spinolaminar line (Figure 1A). Wolfe and colleagues found the average anteroposterior diameter was 22 mm at C1, 20 mm at C2, and 17 mm from C3–C7. General consensus has been that between C3–C7, canal heights are normal above 15 mm,1, 2 and spinal stenosis is present below 13 mm.5, 9
In 1986, Torg and co-workers16 and, in 1987, Pavlov and co-workers13 described a new method to radiographically assess cervical spinal stenosis using a ratio method to eliminate the need to correct for radiographic magnification error. The height of the spinal canal as measured from the midpoint of the posterior surface of the vertebral body up to the spinolaminar line is the numerator and the denominator is the height of the corresponding midvertebral body (Figure 1B). A vertebral canal/vertebral body ratio under 0.80 was defined as “significant spinal stenosis.” The authors also conclude that our “data clearly indicate that athletes who have developmental spinal stenosis are not predisposed to more severe injuries with associated permanent neurological sequelae.”16
Recently, the ratio method as a means to define spinal stenosis has been shown to be of low predictive value. First, the Kerlan Jobe Orthopedic Clinic found the incidence of spinal stenosis using the Torg “ratio” to be 33% in 124 professional and 100 rookie football players.12 Then Herzog and associates7 found in 80 asymptomatic professional football players that 49% had abnormal “ratios” below 0.80 at one or more cervical levels. They also found the “ratio” to be highly unreliable in determining spinal stenosis with a positive predictive value of only 12%. Herzog and colleague7 theorized the Torg ratio had a lot of false-positives (88% of the time) because the large vertebral bodies of larger athletes skewed the ratio, and they were right. The cervical spinal canal heights (numerator) of all the athletes they studied were within normal limits. The athletes with abnormal Torg ratios had extremely large vertebral bodies (denominator), which brought the ratio below 0.80.
They, thus concluded “if an abnormal Torg ratio is detected, further evaluation is necessary before an athlete can be diagnosed as “significantly spinal stenotic.”8 This is extremely important to understand because any literature that makes comments that used the ratio method to define stenosis is very suspect because true stenosis was likely not present in 88% of the cases.
Even in the small percentage of professional football players in Herzog and colleagues study7 (with spinal stenosis defined as canal size by MR image two standard deviations below the mean), none had experienced spinal cord symptoms and none had “functional cervical spinal stenosis” defined as a cervical spinal canal so small as to obliterate the protective cushion of cerebrospinal fluid (CSF) (Figure 2), or in more extreme cases, deformation of the spinal cord itself (Figure 3).
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| Address reprint requests to Robert C. Cantu, MD, FACS, FACSM, Service of Sports Medicine, Emerson Hospital, Concord, MA 01742 |
Vol 17 - N° 1
P. 121-126 - janvier 1998 Regresar al número
Artículo precedente
- ATHLETIC SPINAL CORD AND SPINE INJURIES : Guidelines for Initial Management
- Jack E. Wilberger
- ASSESSMENT AND REHABILITATION OF THE ATHLETE WITH A “STINGER” : A Model for the Management of Noncatastrophic Athletic Cervical Spine Injury
- Stuart M. Weinstein
Bienvenido a EM-consulte, la referencia de los profesionales de la salud.
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