OBJECTIVE: Although trunk muscles in the lumbar spine preserve spinal stability and motility, little is known about the relationship between trunk muscles and spinal fusion rate. The aim of the present study is to evaluate the correlation between trunk muscles cross sectional area (MCSA) and fusion rate after posterior lumbar interbody fusion (PLIF) using stand-alone cages. METHODS: A total of 89 adult patients with degenerative lumbar disease who were performed PLIF using stand-alone cages at L4-5 were included in this study. The cross-sectional area of the psoas major (PS), erector spinae (ES), and multifidus (MF) muscles were quantitatively evaluated by preoperative lumbar magnetic resonance imaging at the L3-4, L4-5, and L5-S1 segments, and bone union was evaluated by dynamic lumbar X-rays. RESULTS: Of the 89 patients, 68 had bone union and 21 did not. The MCSAs at all segments in both groups were significantly different (p<0.05) for the PS muscle, those at L3-4 and L4-5 segments between groups were significantly different (p=0.048, 0.021) for the ES and MF muscles. In the multivariate analysis, differences in the PS MCSA at the L4-5 and L5-S1 segments remained significant (p=0.048, 0.043 and odds ratio=1.098, 1.169). In comparison analysis between male and female patients, most MCSAs of male patients were larger than female's. Fusion rates of male patients (80.7%) were higher than female's (68.8%), too. CONCLUSION: For PLIF surgery, PS muscle function appears to be an important factor for bone union and preventing back muscle injury is essential for better fusion rate.
Adult ; Back Muscles ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Multivariate Analysis ; Muscles* ; Paraspinal Muscles ; Spinal Fusion ; Spine

Surface electromyogram in the lumbar paraspinal muscles was studied to evaluate back muscle impairment in twenty chronic low back pain patients and twenty control subjects. Turns-amplitude and power spectrum analysis of electromyographic signals were performed at different force levels during fatigue from sustained isometric contraction and recovery from fatigue in trunk extensor muscles. Results indicated that with increasing force level mean amplitude and Root Mean Square (RMS) values were increased, but mean and median frequencies increased initially until 20% Maximal Voluntary Contraction (MVC) and decreased tendency after then. Turns, mean amplitude, RMS, mean and median frequencies were all higher in control subject than those of low back pain patients. During sustained isometric contraction at 70% MVC, mean and median frequencies were linearly decreased, and the slopes were steeper in the patients group. Mean amplitude and RMS value showed decreased tendency during fatigue. During recovery from fatigue turns, mean and median frequencies increased especially in the first 3 minutes and nearly completely recovered in the 7~8 minutes in both patients and control groups. Therefore the mean amplitude and RMS value could be used as indicators of the level of muscle contraction and the mean and median frequencies reflect well the muscle fatigue in paralumbar muscle. These results validate the use of surface EMG spectral parameters as an objective measure of back muscle impairment in chronic low back pain patients.
Back Muscles* ; Back Pain ; Fatigue ; Humans ; Isometric Contraction ; Low Back Pain* ; Muscle Contraction ; Muscle Fatigue ; Muscles ; Paraspinal Muscles ; Spectrum Analysis

We investigated the fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age. One- and two-year-old fish were cultured in floating net cages and sampled randomly for analysis. Moisture, protein, lipid and ash contents were determined by methods of Association of Analytical Chemist (AOAC) International. Fatty acid profile was determined by gas chromatography. Crude protein, fat, moisture and ash contents showed no significant differences between the two age groups. The contents of total polyunsaturated fatty acids and docosahexaenoic acid (DHA) were significantly higher and eicosapentaenoic acid (EPA) content was significantly lower in the two-year-old large yellow croaker than in the one-year-old (P<0.05). No significant differences were observed in the contents of total saturated fatty acids and monounsaturated fatty acids, or the ratio of n-3/n-6 fatty acids among the large yellow croakers of the two age groups. We conclude that large yellow croakers are good food sources of EPA and DHA.
Age Factors ; Animals ; Fatty Acids ; analysis ; Muscles ; chemistry ; Perciformes ; metabolism

The human mandible is always under the condition of loading by the various forces exterted by the attached muscles. The loading is an important condition of the stomatognathic system. This condition is composed of the direction and amount of forces of the masticatory muscles, which are controlled by the neuromuscular system, and always influenced by the movement of both opening and closing. Mandible is a strong foundation for the teeth or various prostheses, nevetheless it is a elastic body which accompanies deformation by the external forces on it. The elastic properties of the mandible is influenced by the various procedures such as conventional restorative treatments, osseointegrated implant treatments, reconstructive surgical procedures and so forth. Among the treatments the osseointegrated implant has no periodontal ligaments, which exist around the natural teeth to allow physiologic mobility in the alveolar socket. And so around the osseointegrated implant, there is almost no damping effect during the transmission of occlusal stree and displacements. If the osseointegrated implants are connceted by the superstructure for the stabilization and effective distribution of occlusal stresses, the elastic properties of mandible is restricted accordding to the extent of 'splinting'by the superstructure and implants. To investigate the change of elastic behaviour of the mandible which has osseointegrated impalnt prosthesis of various numbers of implant installment and span of superstructure, a three dimensional finite element model was developed and analyzed with conditions mentioned above. The conclusions are as follows : 1. The displacements are primarily developed at the area of muscle attachment and distributed all around the mandible according to the various properties of bone. 2. The segmentation in the superstructure has few influence on the distribution of stress and displacement. 3. In the load case of ICP, the concetration of tensional stress was observed at the anterior portion of the ramus(9.22E+6Nmm2) and at the lingual portion of the symphysis menti(8.36E+6Nmm2). 4. In the load case of INC, the concentration of tensional stress was observed at the anterior portion of the ramus(9.90E+6Nmm2) and the concentration of tensional stress was observed at the lingual portion of the symphysis menti(2.38E+6Nmm2). 5. In the load case of UTCP, the relatively high concentration of tensional stress(3.66E+7N/mm2) was observed at the internal surface of the condylar neck.
Finite Element Analysis* ; Humans ; Mandible* ; Masticatory Muscles ; Muscles ; Neck ; Periodontal Ligament ; Prostheses and Implants* ; Reconstructive Surgical Procedures ; Stomatognathic System ; Tooth

Intramedullary screw fixation and bicortical screw fixation are widely used operation methods in the surgical treatment of Jones fractures. The purpose of this study is to evaluate of mechnical stability in two kind of Jones fracture. Using Mimics, three-dimensional models of the fifth metatarsal were reconstructed form computed tomography images of a 23-year-old Korean healthy male. Normal and osteoporotic bone models were made by changing bone density or thickness of cortical and cancellous bone. Two kinds of fixation techniques, i.e., intramedullary and bicortical screw fixation models, were simulated and muscles forces related to the fifth metatarsal base were applied. Maximum contact pressure difference were measured as 20,818 MPa, 12,155 MPa in normal bone, 23,371 MPa, 13,765 MPa in 85% cancellous osteoporotic bone, 24,310 MPa and 14,264 MPa in 75% cancellos osteoporotic model, 21,337 MPa, 20,971 MPa in -0.5 mm cortical osteoporotic bone, 26,322 MPa and 36,153 MPa in -1 mm cortical osteoporotic model, respectively for intramedullary screw fixation and bicortical screw fixation. Displacements on fracture interface were 0.208 mm, 0.126 mm in normal bone while 0.229 mm, 0.127 mm in 85% cancellos osteoporotic model, 0.241 mm, 0.127 mm in 75% cancellos osteoporotic model, 0.223 mm, 0.271 mm in -0.5 mm cortical osteoporotic model, 0.292 mm, 0.480 mm in -1 mm cortical osteoporotic model, respectively for intramedullary screw fixation and bicortical screw fixation. Bicortical screw fixation is superior in mechanical stability than intramedullary screw fixation for normal bone quality Jones fractures. For cortical osteoporotic bone Jones fractures, however, intramedullary screw fixation can give a better mechanical stability than bicortical screw fixation.
Bone Density ; Finite Element Analysis* ; Fracture Fixation ; Humans ; Male ; Metatarsal Bones ; Muscles ; Young Adult

PURPOSE: The purpose of this study was to propose finite element (FE) modeling methods for predicting stress distributions on teeth and mandible under chewing action. MATERIALS AND METHODS: For FE model generation, CT images of skull were translated into 3D FE models, and static analysis was performed considering linear material behaviors and nonlinear geometrical effect. To find out proper boundary and loading conditions, parametric studies were performed with various areas and directions of restraints and loading. The loading directions are prescribed to be same as direction of masseter muscle, which was referred from anatomy chart and CT image. From the analysis, strain and stress distributions of teeth and mandible were obtained and compared with experimental data for model validation. RESULTS: As a result of FE analysis, the optimized boundary condition was chosen such that 8 teeth were fixed in all directions and condyloid process was fixed in all directions except for forward and backward directions. Also, fixing a part of mandible in a lateral direction, where medial pterygoid muscle was attached, gave the more proper analytical results. Loading was prescribed in a same direction as masseter muscle. The tendency of strain distributions between the teeth predicted from the proposed model were compared with experimental results and showed good agreements. CONCLUSION: This study proposes cost efficient FE modeling method for predicting stress distributions on teeth and mandible under chewing action. The proposed modeling method is validated with experimental data and can further be used to evaluate structural safety of dental prosthesis.
Dental Prosthesis ; Finite Element Analysis ; Mandible ; Masseter Muscle ; Mastication ; Pterygoid Muscles ; Skull ; Sprains and Strains ; Tooth

Surface EMG (sEMG) signal is a complex nonlinear, non-stationary signal. In this paper, wavelet transform with nonlinear scale (NWT) is introduced. Due to the gradual shortening of its time-resolution, NWT is good at extracting the precise time-frequency information from sEMG signal. First, every sEMG signal (30 sets are for forearm supination and 30 sets are for forearm pronation) is transformed into intensity distribution (time-frequency distribution) by NWT. And then the feature vector is determined from the characteristic roots which are obtained from the intensity distribution by principle component analysis. At last, the two patterns of sEMG signals are identified by BP neural network. The results show that the accurate classification rate is higher gained by NWT than by two conventional time-frequency distributions. At the same time, the calculating complexity of neural network is decreased greatly.
Electromyography ; Humans ; Muscles ; physiology ; Neural Networks (Computer) ; Principal Component Analysis ; Signal Processing, Computer-Assisted

OBJECTIVE: To quantify activities of bulbocavernosus reflex (BCR) using root mean square (RMS) value of motor unit action potentials in power spectrum analysis. METHOD: Twenty-six male patients with spinal cord injury were studied. The BCRs were evaluated by one examiner. The patients were assigned into absent, hypoactive and normal reflex groups according to the degree of BCR activity. The electrophysiological activities of the BCRs were evaluated by the RMS value of the motor unit action potentials in power spectrum analysis recorded from the bulbocavernosus muscle using concentric needle electrode. RESULTS: The BCR by clinical examination was absent in 6 patients, hypoactive in 10 patients and normal in 10 patients. RMS values of absent, hypoactive and normal BCR groups were 15.1+/-3.6 uV, 26.7+/-13.2 uV and 36.3+/-4.8 uV, respectively. RMS values of three groups were significant different (p=0.028) and showed significant correlation (r=0.714, p= 0.005). CONCLUSION: There was strong correlation between RMS value of motor unit action potentials of bulbocavernosus muscle and degree of BCR activities estimated by clinical examination in patients with spinal cord injury.
Action Potentials ; Electrodes ; Humans ; Male ; Muscles ; Needles ; Reflex ; Spectrum Analysis ; Spinal Cord ; Spinal Cord Injuries

PURPOSE: The aim of this study was to evaluate the transfer of different occlusal forces in various skeletal malocclusions using finite element analysis (FEA). METHODS: Three representative human cone-beam computed tomography (CBCT) images of three skeletal malocclusions were obtained from the Department of Orthodontics, Yonsei University Dental Hospital, Seoul, South Korea. The CBCT scans were read into the visualization software after separating bones and muscles by uploading the CBCT images into Mimics (Materialise). Two separate three-dimensional (3D) files were exported to visualize the solid morphology of skeletal outlines without considering the inner structures. Individual dental impressions were taken and stone models were scanned with a 3D scanner. These images were integrated and occlusal motions were simulated. Displacement and Von Mises stress were measured at the nodes of the FEA models. The displacement and stress distribution were analyzed. FEA was performed to obtain the 3D deformation of the mandibles under loads of 100, 150, 200, and 225 kg. RESULTS: The distortion in all three skeletal malocclusions was comparable. Greater forces resulted in observing more distortion in FEA. CONCLUSIONS: Further studies are warranted to fully evaluate the impact of skeletal malocclusion on masticatory performance using information on muscle attachment and 3D temporomandibular joint movements.
Bite Force ; Computer Simulation ; Cone-Beam Computed Tomography ; Finite Element Analysis* ; Humans ; Korea ; Malocclusion* ; Mandible ; Muscles ; Orthodontics ; Seoul ; Temporomandibular Joint

BACKGROUND/AIMS: Various factors have been reported that can predict the clinical course and outcome of patients with gastrointestinal (GI) carcinoid tumors. We analyzed the clinical characteristics of GI carcinoid tumors and the factors associated with metastasis. METHODS: We retrospectively analyzed the clinical manifestations, treatment modalities and prognosis of 83 patients with GI carcinoid tumors. RESULTS: The mean age of the patients was 48 years old. The locations of the carcinoid tumors were rectum (n=60), stomach (n=12), duodenum (n=6), appendix (n=4) and colon (n=1). The most common symptom was non-specific (n=65, 79.5%), and the mean tumor size was 11.2 mm. The main treatment modality was endoscopic resection (n=66, 79.5%). Nine patients showed metastasis, and all of their tumors were larger than 2 cm. Univariate analysis revealed that size, ulceration and invasion of the proper muscle layer were significant factors associated with metastasis. Tumor size (p=0.001) was the only independent factor on multivariate analysis. CONCLUSIONS: The diagnosis of small sized, asymptomatic GI carcinoid tumors has increased and endoscopic treatment was a useful modality. Tumor size was a predictive factor for metastasis.
Appendix ; Carcinoid Tumor ; Colon ; Duodenum ; Humans ; Multivariate Analysis ; Muscles ; Neoplasm Metastasis ; Prognosis ; Rectum ; Retrospective Studies ; Stomach ; Ulcer