Tamara D. Lauder

The relation between stress fractures and bone mineral density: evidence from active-duty Army women.

OBJECTIVE To determine if bone mineral density (BMD) is associated with the probability of stress fractures in premenopausal women. DESIGN Case-control study. SETTING Large Army post, Fort Lewis, WA. PARTICIPANTS Twenty-seven active duty Army women with documented stress fractures within the last 2 years and 158 female controls. METHODS AND MAIN RESULTS All subjects were examined and interviewed. BMD of the femoral neck and posteroanterior lumbar spine (L2-L4) was measured using dual energy X-ray absorptiometry. Univariate comparisons revealed no significant differences in BMD of the femoral neck or lumbar spine between groups. Women with stress fractures had a significantly higher exercise intensity (428 vs 292 minutes per week, p<.05) and were more likely to be entry-level enlisted soldiers (63% vs. 44%, p<.05) than those without stress fractures. Multivariate analyses revealed a strong negative association between femoral neck BMD and the probability of stress fractures (lower BMD, higher risk). Exercise intensity and body mass index had a significant positive effect on BMD of the femoral neck and lumbar spine, yet both were associated with an increased probability of stress fractures. CONCLUSIONS Femoral neck BMD was significantly associated with the probability of stress fractures. Optimal training programs should balance the beneficial indirect effect of increased exercise (through increased BMD) with its detrimental direct effect on stress fractures.

Identifying lumbosacral radiculopathies: An optimal electromyographic screen

ObjectiveThe objective of this study was to determine prospectively the optimal electromyographic screening examination of the lower limb that ensures identification of those lumbosacral radiculopathies that can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DesignA prospective multicenter study was conducted from May 1996 to September 1997. Patients with suspected lumbosacral radiculopathy referred to participating electrodiagnostic laboratories were recruited and examined by needle electromyography using a standard set of muscles. Patients with electrodiagnostically confirmed lumbosacral radiculopathies were selected for analysis. Various muscle screens were tested against this group of patients with radiculopathies to determine the frequency with which each screen identified the patient with radiculopathy. ResultsThere were 102 patients identified. When paraspinal muscles were one of the screening muscles, four-muscle screens identified 88–97% of the radiculopathies, five-muscle screens identified 94–98%, and six-muscle screens 98–100%. When paraspinal muscles were not part of the screen, identification rates were lower for all screens, and eight distal muscles were necessary to identify about 90% of the radiculopathies. ConclusionsSix-muscle screens with paraspinal muscles yielded consistently high identification rates. Studying additional muscles produced no improvements in identification.

Identification of cervical radiculopathies: Optimizing the electromyographic screen

Dillingham TR, Lauder TD, Andary M, Kumar S, Pezzin LE, Stephens RT, Shannon S: Identification of cervical radiculopathies: optimizing the electromyographic screen. Am J Phys Med Rehabil 2001; 80:84–91. ObjectiveTo determine the optimal electromyography screening examination of the upper limb that ensures detection of those cervical radiculopathies, which can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DesignA prospective multicenter study was conducted from May 1996 to September 1997 at five institutions. Patients who were referred to participating electrodiagnostic laboratories with suspected cervical radiculopathy were recruited. A standard set of muscles were examined by needle electromyography. Patients with electrodiagnostically confirmed cervical radiculopathies, based on electromyography findings, were selected for analysis. Muscle screens were tested against this group to determine whether the screen identified the patients with radiculopathy. ResultsThere were 101 patients with cervical radiculopathies representing all cervical root levels. When paraspinal muscles were one of the screening muscles, five muscle screens identified 90% to 98% of radiculopathies, six muscle screens identified 94% to 99%, and seven muscle screens identified 96% to 100%. When paraspinal muscles were not part of the screen, eight distal limb muscles recognized 92% to 95% of radiculopathies. ConclusionThis study demonstrated that six muscle screens including paraspinal muscles yielded consistently high identification rates. Studying additional muscles led to marginal increases in identification.

Effect of history and exam in predicting electrodiagnostic outcome among patients with suspected lumbosacral radiculopathy.

OBJECTIVE To determine the extent to which the history and physical examination predict the outcome of the electrodiagnostic (EDX) evaluation in patients with suspected lumbosacral radiculopathy. DESIGN Data for 170 subjects referred for low-back and lower limb symptoms were prospectively collected at five EDX laboratories. The sensitivity, specificity, positive and negative predictive values, and odds ratios were determined for symptoms and neurologic signs. RESULTS Symptoms were not significantly associated with an EDX study or a lumbosacral radiculopathy. The physical examination was better at predicting that an EDX study would be abnormal in general than it was at predicting a lumbosacral radiculopathy in particular. Of those subjects with normal physical examinations, 15%-18% still had abnormal EDX findings. CONCLUSIONS In a population of patients referred for an EDX study, the history and physical examination alone cannot reliably predict electrodiagnostic outcome.

Exertional compartment syndrome and the role of magnetic resonance imaging.

A 47-yr-old woman presented with a 1-yr history of progressive bilateral anterior lower leg pain and swelling with walking, which resolved 10 min after activity. Postexercise (forced dorsiflexion) magnetic resonance imaging revealed increased T2 signal intensity in the entire anterior muscle compartment, and anterior compartment pressures were elevated at rest and postexercise. Chronic exertional compartment syndrome can occur in some patients after even minimal physical activities, and magnetic resonance imaging without the use of radioisotopes was a useful adjunct for diagnosis.

Musculoskeletal disorders that frequently mimic radiculopathy.

Recognition of the musculoskeletal disorders presented in this article is important for the clinician evaluating patients with spine problems and plays a key role in the patients care. The musculoskeletal disorders discussed in this article generally respond well to conservative treatment. An understanding of musculoskeletal pain problems is important to avoid subjecting patients to unnecessary and often expensive and invasive diagnostic procedures and treatments. Treatment of concomitant musculoskeletal disorders in patients with radiculopathy improves patient satisfaction and outcomes.

LUMBOSACRAL RADICULOPATHY SCREEN: Optimizing the Number of Muscles Studied

ABSTRACT The literature is unclear as to which muscles and how many are required for a sensitive lumbosacral radiculopathy (LSR) screen. A retrospective study of 247 electrodiagnostically confirmed LSRs in 201 patients over a 3-yr period was conducted to determine how many muscles were required to identify a LSR. All LSRs showed abnormal spontaneous activity (positive waves or fibrillation potentials) in two or more muscles innervated by the same nerve root level but different peripheral nerves. All cases were categorized by radiculopathy level, and the most frequently abnormal individual muscles were combined into different muscle screens. The frequency with which each muscle screen identified a radiculopathy was the frequency with which one or more muscles in the screen displayed abnormal spontaneous activity divided by the total number of radiculopathies. The paraspinal muscles (PM) alone identified 88% of LSRs. Without PM, two muscle screens identified only 14–68%, three muscle screens identified 37–89% and four muscle screens identified 45–92%. Including PM, three muscle screens identified 86–94% of LSRs, four muscle screens identified 91–97% and five muscle screens yielded 94–98% identification. Seven to ten muscle screens resulted in minimal improvements in identifying a LSR with 98–99% identification. We conclude that five muscle LSR screens, including PM, are sufficient to identify LSRs while minimizing patient discomfort and examiner time.

Physical examination signs, clinical symptoms, and their relationship to electrodiagnostic findings and the presence of radiculopathy.

The validity of the history and physical examination varies with study method and the gold standard used. In general, symptoms are more sensitive than specific, and most patients with radiculopathy do present with some characteristic complaints. With the exception of the ipsilateral SLR, most physical examination findings are more specific than sensitive. In patients with suspected radiculopathy, having at least one abnormal physical examination finding makes the probability of having an abnormal electrodiagnostic study more likely than if the results of the physical examination are normal. Having a normal physical examination, however, does not rule out the possibility of having a radiculopathy that is revealed either electrodiagnostically or surgically. Although the history and physical examination may not be perfect tools for the diagnosis of radiculopathy or predicting electrodiagnostic outcome, they are an essential part of the clinical evaluation to assist in formulating a differential diagnosis and guiding the electrodiagnostic study.

Cervical radiculopathies: Relationship between symptom duration and spontaneous EMG activity

The purpose of this multicenter study was to prospectively examine whether denervation in paraspinal muscles (PSM) and in other major proximal and distal muscles is related to symptom duration in cervical radiculopathies (CRs). Information was collected on 93 electrodiagnostically confirmed CRs using standardized history, physical examination, and electromyographic (EMG) screens. Multivariate, maximum‐likelihood estimates showed no evidence of correlation between PSM spontaneous activity and symptom duration. Symptom duration was also nonsignificant in eight of the remaining nine upper limb muscles analyzed. We conclude that the probability of spontaneous activity is not related to symptom duration. Clinicians, therefore, should refrain from interpreting electrodiagnostic findings based upon duration of symptoms.

Symptom duration and spontaneous activity in lumbosacral radiculopathy

OBJECTIVES A long-held notion in the electrodiagnostic literature is that paraspinal muscles tend to show spontaneous activity (fibrillations and positive sharp waves) on needle electromyography, early on in a lumbosacral radiculopathy, and that more distal muscles become abnormal later in the disease process. The purpose of this study was to determine whether paraspinal muscle and other major proximal and distal muscle spontaneous activity is related to a lumbosacral radiculopathy symptom duration. METHODS A multicenter, prospective study that collected standard information on history, physical examination, and electrodiagnostic findings in patients with electrodiagnostically confirmed lumbosacral radiculopathies was undertaken. RESULTS Multivariate probit analyses of 96 patients identified with a lumbosacral radiculopathy showed no evidence of correlation between spontaneous activity in the paraspinal muscles and symptom duration. Symptom duration was also nonsignificant in nine of the remaining ten lower limb muscles analyzed. CONCLUSION These findings emphasize the limitations of using symptom duration when interpreting electrodiagnostic findings in lumbosacral radiculopathy.