Correspondence
Lumbar Spinal Stenosis
N Engl J Med 2008; 358:2647-2648June 12, 2008
- Article
To the Editor:
As Katz and Harris (Feb. 21 issue)1 note, electromyography is not routinely necessary in the diagnostic workup of spinal stenosis. However, a complete electrodiagnostic examination (i.e., nerve-conduction studies and electromyography) can often be quite helpful in differentiating symptoms related to spinal stenosis from those due to a peripheral neuropathy. In general, a patient with clinically significant spinal stenosis will have electromyographic evidence of multilevel lumbosacral radiculopathies with essentially normal nerve-conduction studies, whereas a patient with clinically significant peripheral neuropathy will have just the opposite findings (i.e., abnormal nerve-conduction studies and normal electromyography).2 Even when both disorders are present, it is frequently possible to identify the one that is more symptomatic, since electrodiagnostic testing can also delineate the severity of each process.
2 ReferencesPatrick Kortebein, M.D.
Central Arkansas Veterans Healthcare System, North Little Rock, AR 722141
Katz JN ,Harris MB . Lumbar spinal stenosis. N Engl J Med 2008;358:818-825
Full Text | Web of Science | Medline2
Dumitru D, Zwarts MJ. Radiculopathies. In: Dumitru D, Amato AA, Zwarts MJ, eds. Electrodiagnostic medicine. 2nd ed. Philadelphia: Hanley & Belfus, 2002:757-8.
To the Editor:
Katz and Harris did not discuss recent evidence that provides support for the role of physical therapy in the treatment of lumbar spinal stenosis. A randomized trial in 2006 showed that patients who walked on a treadmill with body-weight support and received manual physical therapy improved significantly (P=0.002) in measures of disability, satisfaction, and treadmill walking as compared with those who participated in just the treadmill and exercise program.1 These results were maintained at 1 year. When evaluating the effects of nonsurgical care, it is important to differentiate what may be standard practice from what is current best evidence-based practice.
1 ReferencesDaniel Rhon, D.P.T.
Baylor University, San Antonio, TX 78234
daniel.rhon@amedd. army. mil 1
Whitman JM ,Flynn TW ,Childs JD , et al. A comparison between two physical therapy treatment programs for patients with lumbar spinal stenosis: a randomized clinical trial. Spine 2006;31:2541-2549
CrossRef | Web of Science | Medline
To the Editor:
Katz and Harris refer to a study in which “the finding of a wide-based gait among patients with back pain had a specificity exceeding 90% for lumbar spinal stenosis.” In the preceding sentence, this feature is attributed to involvement of the posterior columns. I take issue with both the observation and the interpretation. The study in question, of which Katz was the first author,1 provided no definition of “wide-based gait,” and the diagnostic value of the sign was not tested in a different population. The reference to the posterior columns is misleading, since normally the lumbar spinal canal contains only the roots of the cauda equina, not the spinal cord with its columns. The cord ends at the level of the first lumbar vertebra.
1 ReferencesJan van Gijn, M.D.
University Medical Center, 3584 CX Utrecht, the Netherlands
j.vangijn@umcutrecht. nl 1
Katz JN ,Dalgas M ,Stucki G , et al. Degenerative lumbar spinal stenosis: diagnostic value of the history and physical examination. Arthritis Rheum 1995;38:1236-1241
CrossRef | Web of Science | Medline
Author/Editor Response
We agree with Kortebein that electromyography and nerve-conduction studies are useful in distinguishing the polyradiculopathy of lumbar spinal stenosis from peripheral neuropathy. We are not aware of data indicating that the severity of electrodiagnostic findings can be used to identify whether radiculopathy or coexisting neuropathy is the most symptomatic process in a patient who has both disorders.
Rhon points to a randomized trial that was not included in our review. This study shows the efficacy of manual physical therapy in conjunction with a treadmill-walking program with body-weight support as compared with flexion exercises and the treadmill-walking program. These promising findings merit further investigation.
Our 1995 report on the sensitivity and specificity of medical-history and physical findings in patients with spinal stenosis1 identified wide-based gait, in which patients walk with their feet separated by a greater-than-usual distance, as a sign that is insensitive (present in 43% of patients with stenosis) but specific (absent in 91% of patients without stenosis) and that helps to distinguish lumbar spinal stenosis from other sources of back pain. As van Gijn suggests, further work on the reliability and validity of this and other medical-history and physical findings would be a welcome addition to the literature. We appreciate van Gijn's clarification regarding the presence of descending nerve roots, rather than the posterior column (spinal cord), at the lower lumbar levels.
1 ReferencesJeffrey N. Katz, M.D.
Mitchel B. Harris, M.D.
Brigham and Women's Hospital, Boston, MA 02115
jnkatz@partners.org 1
Katz JN ,Dalgas M ,Stucki G , et al. Degenerative lumbar spinal stenosis: diagnostic value of the history and physical examination. Arthritis Rheum 1995;38:1236-1241
CrossRef | Web of Science | Medline
