Masaki Tatsumura

Trunk Muscle Activity During Lumbar Stabilization Exercises on Both a Stable and Unstable Surface

STUDY DESIGN Controlled laboratory study. OBJECTIVES To clarify whether differences in surface stability influence trunk muscle activity. BACKGROUND Lumbar stabilization exercises on unstable surfaces are performed widely. One perceived advantage in performing stabilization exercises on unstable surfaces is the potential for increased muscular demand. However, there is little evidence in the literature to help establish whether this assumption is correct. METHODS Nine healthy male subjects performed lumbar stabilization exercises. Pairs of intramuscular fine-wire or surface electrodes were used to record the electromyographic signal amplitude of the rectus abdominis, the external obliques, the transversus abdominis, the erector spinae, and lumbar multifidus. Five exercises were performed on the floor and on an unstable surface: elbow-toe, hand-knee, curl-up, side bridge, and back bridge. The EMG data were normalized as the percentage of the maximum voluntary contraction, and data between doing each exercise on the stable versus unstable surface were compared using a Wilcoxon signed-rank test. RESULTS With the elbow-toe exercise, the activity level for all muscles was enhanced when performed on the unstable surface. When performing the hand-knee and side bridge exercises, activity level of the more global muscles was enhanced when performed on an unstable surface. Performing the curl-up exercise on an unstable surface, increased the activity of the external obliques but reduced transversus abdominis activation. CONCLUSION This study indicates that lumbar stabilization exercises on an unstable surface enhanced the activities of trunk muscles, except for the back bridge exercise.

Electromyographic Analysis of Transversus Abdominis and Lumbar Multifidus Using Wire Electrodes During Lumbar Stabilization Exercises

STUDY DESIGN Experimental laboratory study. OBJECTIVES To measure trunk muscle activity using wire electrodes during lumbar stabilization exercises and to examine if more effective exercises to activate the deep trunk muscles (local muscles) exist. BACKGROUND Lumbar stabilization exercises are performed to improve motor control of trunk muscles. However, the magnitude of activation of local muscles during lumbar stabilization exercises is not clear. METHODS Nine healthy men with no history of lumbar spine disorders participated in the study. Fine-wire electrodes were inserted into the transversus abdominis (TrA) and lumbar multifidus, bilaterally. In addition, surface electrodes were attached to the rectus abdominis, external obliques, and erector spinae, bilaterally. Electromyographic signal amplitude was measured during the following exercises: elbow-toe, hand-knee, back bridge, side bridge, and curl-up. Two-way analyses of variance were used to compare muscle activity level among exercises and between sides for each muscle. RESULTS The exercise showing the greatest activity level for the TrA was elbow-toe exercise with contralateral arm and leg lift. In addition, for the TrA, a significant side-to-side difference in activation level was demonstrated for 7 of the 11 exercises that were performed. The activity level of the multifidus was greatest during the back bridge exercises. The curl-up exercise generated the highest activity level for the rectus abdominis and the back bridge, with single-leg lift exercises generating the highest erector spinae activity. CONCLUSIONS The exercises investigated in this study resulted in a wide range of effort level for all 5 muscles monitored. Many of the exercises also resulted in an asymmetrical (right versus left side) activation level for a muscle, including the TrA.

Femoral nerve palsy caused by a huge iliopectineal synovitis extending to the iliac fossa in a rheumatoid arthritis case.

We report on a 54-year-old woman with rheumatoid arthritis who had severe femoral nerve palsy affected by a distended synovium in the hip joint. Surgical exploration demonstrated a perforation of the iliopectineal bursa connecting with the hip joint. The patient fully recovered from femoral nerve palsy after surgery. It was considered that synovitis of the hip joint had developed following huge iliopectineal bursitis.

Off-loading of cyclic hydrostatic pressure promotes production of extracellular matrix by chondrocytes.

The addition of cyclic hydrostatic pressure (cHP) to cell culture medium has been used to promote extracellular matrix (ECM) production by articular chondrocytes. Though a combination of cHP followed by atmospheric pressure (AP) has been examined previously, the rationale of such a combination was unclear. We compared the effects of loading once versus twice (combinations of cHP followed by AP) regarding both gene expression and biochemical and histological phenotypes of chondrocytes. Isolated bovine articular chondrocytes were embedded in a collagen gel and incubated for 14 days under conditions combining cHP and AP. The gene expression of aggrecan core protein and collagen type II were upregulated in response to cHP, and those levels were maintained for at least 4 days after cHP treatment. Accumulation of cartilage-specific sulfated glycosaminoglycans following cHP for 7 days and subsequent AP for 7 days was significantly greater than that of the AP control (p < 0.05). Therefore, incubation at AP after loading with cHP was found to beneficially affect ECM accumulation. Manipulating algorithms of cHP combined with AP will be useful in producing autologous chondrocyte-based cell constructs for implantation.

COMPARISON OF THE ACTIVITIES OF THE DEEP TRUNK MUSCLES MEASURED USING INTRAMUSCULAR AND SURFACE ELECTROMYOGRAPHY

Surface electromyography (EMG) has been used to estimate deep trunk muscle activity. However, it remains unknown whether surface EMG provides an accurate estimation of this activity. The purposes of this study were to compare surface and intramuscular EMG activity measurements and investigate the efficacy of surface EMG measurement for the transversus abdominis (TrA) and the multifidus (MF) muscles. Eight healthy men participated in the study. TrA and MF activities were simultaneously measured by both intramuscular and surface EMG during isometric trunk exercises. Spearman correlation coefficients for the relationship between the two activity measurements for the right TrA, left TrA, right MF, and left MF were 0.55, 0.36, 0.67, and 0.79, respectively. For the TrA, Bland–Altman plots revealed that mean differences between measurements obtained by intramuscular EMG and surface EMG were not close to zero, with a systematic bias toward higher surface EMG values. In conclusion, surface and intramuscular EMG ac...

Extraskeletal mesenchymal chondrosarcoma of the cervical meninx

We report a case of recurrent mesenchymal chondrosarcoma in the cervical paravertebral region that was diagnosed preoperatively by imaging studies. The tumor showed findings of a well-differentiated cartilaginous tumor with a characteristic pattern of calcifications on computed tomography (CT). However, it appeared as a soft tissue sarcoma of lower intensity than common cartilaginous tumors on T2-weighted magnetic resonance imaging (MRI). This discrepancy between CT and MRI was well correlated with pathological findings of mesenchymal chondrosarcoma and suggested this entity.

Trunk muscle activity while lifting objects of unexpected weight

OBJECTIVE To determine trunk muscle activity when lifting an object of greater weight than expected, which may contribute to the development of low back pain. DESIGN Electromyographic evaluation of trunk muscle activity. SETTING University of Tsukuba, Spine laboratory. PARTICIPANTS Eleven healthy men with a mean age of 24 (SD 2) years. INTERVENTIONS Trunk muscle activity was measured when subjects lifted an object with their right arm in immediate response to a light stimulus. Surface and wire electrodes were used to measure the activity of the rectus abdominis, external oblique and erector spinae muscles, and the transversus abdominis and lumbar multifidus muscles, respectively. The lifting tests were performed in three different settings: lifting an expected 1-kg object, lifting an unexpected 4-kg object (erroneously expected to weigh 1 kg), and lifting an expected 4-kg object. MAIN OUTCOME MEASURES The muscle activity induced when subjects lifted objects of different weights was compared by calculating the root mean square (RMS) of muscle activity at rest and % maximum voluntary contraction. RESULTS When the subjects were aware of the weight of the object to be lifted, the activity of the external oblique, transversus abdominis, erector spinae and lumbar multifidus muscles increased immediately after lifting. When the subjects were not aware of the weight of the object to be lifted, the increase in muscle activity was delayed (P<0.05). CONCLUSIONS Trunk muscles may not be able to function appropriately when individuals lift an object that is much heavier than expected.

Abdominal Muscle Activity During a Standing Long Jump

STUDY DESIGN Experimental laboratory study. OBJECTIVES To measure the activation patterns (onset and magnitude) of the abdominal muscles during a standing long jump using wire and surface electromyography. BACKGROUND Activation patterns of the abdominal muscles, especially the deep muscles such as the transversus abdominis (TrA), have yet to be examined during full-body movements such as jumping. METHODS Thirteen healthy men participated. Wire electrodes were inserted into the TrA with the guidance of ultrasonography, and surface electrodes were attached to the skin overlying the rectus abdominis (RA) and external oblique (EO). Electromyographic signals and video images were recorded while each subject performed a standing long jump. The jump task was divided into 3 phases: preparation, push-off, and float. For each muscle, activation onset relative to the onset of the RA and normalized muscle activation levels (percent maximum voluntary contraction) were analyzed during each phase. Comparisons between muscles and phases were assessed using 2-way analyses of variance. RESULTS The onset times of the TrA and EO relative to the onset of the RA were -0.13 ? 0.17 seconds and -0.02 ? 0.07 seconds, respectively. Onset of TrA activation was earlier than that of the EO. The activation levels of all 3 muscles were significantly greater during the push-off phase than during the preparation and float phases. CONCLUSION Consistent with previously published trunk-perturbation studies in healthy persons, the TrA was activated prior to the RA and EO. Additionally, the highest muscle activation levels were observed during the push-off phase.

Arthroscopic synovectomy for the treatment of stage II to IV trapeziometacarpal joint arthritis

Objective: As a minimal invasive surgery for the treatment of thumb carpometacarpal joint (trapeziometacarpal [TMC]) arthritis, we performed an arthroscopic synovectomy for Eaton stage II to IV arthritis. Patients and Methods: We included patients who were effectively treated with a corticosteroid injection, experienced recurrence of TMC pain, and had no major instability of the TMC. Surgery was performed in 17 female patients. Synovectomy was performed, when possible, using radiofrequency and a shaver. The mean follow-up period was 27.2 months. Results: Two patients required additional surgery; however, 15 patients were satisfied with the outcome. The mean visual analogue scale score improved from 8.8 preoperatively to 2.2 postoperatively. Conclusion: Arthroscopic synovectomy is indicated to be an effective treatment for stage II to IV TMC arthritis. The goal of this treatment was to relieve severe pain minimally invasively. Furthermore, if symptoms remain or reoccur, another curative procedure can be chosen.

Tumor Occupation in the Spinal Canal and Clinical Symptoms of Cauda Equina Schwannoma: An Analysis of 22 Cases

Study Design Retrospective, radiological study. Purpose To determine the relationship between clinical symptoms and the extent of tumor occupation of the spinal canal by cauda equina schwannoma. Overview of Literature Little is known about the relationship between the size of tumors of the cauda equina and the manifestation of clinical symptoms. We analyzed this relationship by estimating the percentage of tumor occupation (PTO) in the spinal canal in cauda equina schwannomas and by correlating this parameter with the presence and severity of clinical symptoms. Methods Twenty-two patients (9 men and 13 women; age, 19–79 years; mean age, 55.3 years) who were radiologically diagnosed with schwannomas of the cauda equina between April 2004 and July 2014 were retrospectively analyzed. PTO was measured in axial and sagittal magnetic resonance imaging slices in which the cross-sectional area of the tumor was the largest. Data regarding clinical symptoms and results of physical examinations were collected from patient medical records. PTO differences between symptom-positive and -negative groups were analyzed for each variable. Results In the 4 cases in which tumor presence was not related to clinical symptoms, PTO was 5%–10% (mean, 9%) in axial slices and 23%–31% (mean, 30%) in sagittal slices. In the 18 cases in which symptoms were associated with the tumor, PTO was 11%–86% (mean, 50%) in axial slices and 43%–88% (mean, 71%) in sagittal slices. PTO in axial slices was significantly higher in the presence of Déjèrine symptoms and/or muscle weakness, a positive straight leg raise test, and a positive Kemp sign. Conclusions PTO >20% in axial slices and >40% in sagittal slices can be an indication of symptomatic cauda equina schwannoma.