Lumbar flexion and dynamic EMG among persons with single level disk herniation pre- and postsurgery with radicular low-back pain.

OBJECTIVE: The paraspinal muscles often fail to relax on forward flexion in many persons with low-back pain. The goal of this prospective study was to determine whether this abnormal lack of a flexion-relaxation phenomenon corrects after lumbar diskectomy for symptoms of radiculopathy with low-back pain. DESIGN: Electromyographic testing was performed on 17 patients before and 30 days after lumbar diskectomy. RESULTS: Although pain improved significantly (P < 0.05), the flexion-relaxation phenomenon did not improve. CONCLUSIONS: Failure to recover muscle relaxation while pain is relieved suggests another mechanism for paraspinal activity.

False-negative triple-phase bone scans in spinal cord injury to detect clinically suspect heterotopic ossification: a case series.

BACKGROUND/OBJECTIVE: Heterotopic ossification (HO) is a complication seen in patients after spinal cord injury (SCI). Triple-phase nuclear bone scanning is the most sensitive test for the detection of HO. This retrospective study assesses whether patients with clinically suspected HO but negative triple-phase nuclear bone scans develop delayed positive nuclear bone scans. CASE SERIES: A cohort of patients with SCI and clinically suspected HO who underwent triple phase nuclear bone scans over a period of 2 years was identified from retrospective chart review of an acute inpatient SCI rehabilitation service. A subgroup of 7 patients with initially negative but subsequently positive triple-phase nuclear bone scans was identified, and the following data were collected: date, mechanism, admission level, and admission completeness of injury as well as date, number, and results of bone scans. Laboratory studies were also collected during the time of imaging. RESULTS: Over a 2-year period, 343 patients were admitted to the SCI rehabilitation service; 60 patients were suspected of having HO and underwent a total of 85 triple-phase nuclear bone scans. Seven patients were identified with initially negative but subsequently positive bone scans. CONCLUSIONS: In patients with clinically suspicious HO but negative bone scans, follow-up scans are indicated to identify initial false-negative studies.

Alterations of F wave parameters after exercise in symptomatic lumbar spinal stenosis.

OBJECTIVES: The purpose of the study is to investigate changes in F wave parameters after exercise in subjects with symptomatic lumbar spinal stenosis. DESIGN: A total of 19 older patients with lumbar spinal stenosis and neurogenic claudication participated in this cohort study. No one withdrew for adverse effects. All subjects underwent physical therapy, with half performing additional interval-walking exercises. Groups were treated for eight sessions, returning for follow-up at weeks 4 and 8. Changes in F wave indices--minimal latency, chronodispersion, and persistence--were calculated. The treatment group demonstrated worsening of F wave persistence at 8-wk follow-up (P < 0.01). CONCLUSIONS: F wave indices worsened after an interval-walking exercise program. Subjects in the treatment group demonstrated worsening of F wave persistence at 8-wk follow-up.

Pain-related fear, lumbar flexion, and dynamic EMG among persons with chronic musculoskeletal low back pain.

OBJECTIVES: The purpose of this study was to examine the relationship between pain-related fear, lumbar flexion, and dynamic EMG activity among persons with chronic musculoskeletal low back pain. It was hypothesized that pain-related fear would be significantly related to decreased lumbar flexion and specific patterns of EMG activity during flexion and extension. STUDY DESIGN: Data was obtained from subjects who, on a single day, completed self-report measures of pain and pain-related fear, and were interviewed to determine demographic and pain information. Subjects then underwent a dynamic EMG evaluation for which they were asked to stand, then bend forward as far as possible, stay fully flexed, and return to standing. Lumbar EMG and angle of flexion were recorded during this time. A flexion-relaxation ratio (FRR) was computed by comparing maximal EMG while flexing to the average EMG in full flexion. SUBJECTS: Seventy-six persons with chronic musculoskeletal low back pain. RESULTS: Zero-order correlations indicated that pain-related fear was significantly related to reduced lumber flexion (r = -0.55), maximum EMG during flexion (r = -0.38) and extension (r = -0.51), and the FRR (r = -0.40). When controlling for pain and demographic factors, pain-related fear continued to be related to reduced lumbar flexion. Using a path-analytic model to examine whether angle of flexion mediated the relationship between fear and EMG activity, the models examining maximal EMG during flexion and extension supported the notion that pain-related fear influences these measures indirectly through its association with decreased range of motion. Conversely, pain-related fear was independently related to higher average EMG in full flexion, while angle of flexion was not significantly related. Pain-related fear was directly related to a smaller FRR, as well as indirectly through angle of flexion. CONCLUSIONS: Pain-related fear is significantly associated with reduced lumbar flexion, greater EMG in full flexion, and a smaller FRR. The relationship between pain-related fear and EMG during flexion and extension appears to be mediated by reduced lumbar flexion. These results suggest that pain-related fear is directly associated with musculoskeletal abnormalities observed among persons with chronic low back pain, as well as indirectly through limited lumbar flexion. These musculoskeletal abnormalities as well as limited movement may be involved in the development and maintenance of chronic low back pain. In addition, changes in musculoskeletal functioning and flexion associated with pain-related fear may warrant greater attention as part of treatment.

Concordance between rating of perceived exertion and function in persons with chronic, disabling back pain.

Rating of perceived exertion (RPE), or the Borg scale, has been shown to be positively associated with physiologic effort in individuals undergoing cardiovascular assessment. This study examined the correlations between cardiovascular performance, psychosocial factors, and the RPE scale among 50 persons with chronic pain undergoing multidisciplinary assessment. The results indicated a significant negative association between fitness outcome measures (maximum VO2 and endurance on bicycle), psychosocial measures, and age. With a mean maximum heart rate achieved on the exercise bicycle of 79.2% (SD = 8.3), there was no significant association between the highest rating of perceived exertion on the exercise bicycle test and percent of maximum heart rate. Percent of maximum heart rate was significantly related to self-reported pain and disability as well as age. These findings suggest that perceived exertion in this population is not highly correlated with physiologic effort, as other factors such as pain may influence effort ratings.