Biomechanical properties of cervical traction under neck muscle force / 医用生物力学

Objective To establish a three-dimensional(3D) finite element model of cervical vertebrae (C1-7), and study its biomechanical properties under muscle force by cervical traction, so as to provide references for clinical treatment. Methods On the basis of nonlinear finite element model of normal cervical vertebrae and combined with clinical traction methods, cervical traction at the extension angle of 0°, 10°, 20°, 30°, 40° under the same traction weight, was simulated by finite element analysis (FEA) software to obtain and select the joint force and muscle force that were appropriate for FEA on the model. Results In the process of cervical extension by traction, under the muscle force, the average maximum equivalent stress of cervical vertebrae, intervertebral disc and uncovertebral joints increased by 4.86, 1.79, 0.69 MPa, respectively, and the average maximum relative displacement of cervical vertebrae in sagittal and vertical axis direction increased by 11.1, 1.26 mm, respectively. The biomechanical properties of cervical traction were similar to the FEA results reported in the literature. Conclusions Neck muscles play an active role in promoting the stress and displacement of cervical vertebrae, intervertebral discs and uncovertebral joints and it should be taken into consideration when performing cervical traction in clinic. In addition, the traction angle should not be too large: 0°-20° is generally recommended as a relatively safe angle range at the initial stage.

Biomechanical properties of cervical traction under neck muscle force / 医用生物力学

Objective To establish a three-dimensional(3D) finite element model of cervical vertebrae (C1-7),and study its biomechanical properties under muscle force by cervical traction,so as to provide references for clinical treatment.Methods On the basis of nonlinear finite element model of normal cervical vertebrae and combined with clinical traction methods,cervical traction at the extension angle of 0°,10°,20°,30°,40° under the same traction weight,was simulated by finite element analysis (FEA) software to obtain and select the joint force and muscle force that were appropriate for FEA on the model.Results In the process of cervical extension by traction,under the muscle force,the average maximum equivalent stress of cervical vertebrae,intervertebral disc and uncovertebral joints increased by 4.86,1.79,0.69 MPa,respectively,and the average maximum relative displacement of cervical vertebrae in sagittal and vertical axis direction increased by 1 1.1,1.26 mm,respectively.The biomechanical properties of cervical traction were similar to the FEA results reported in the literature.Conclusions Neck muscles play an active role in promoting the stress and displacement of cervical vertebrae,intervertebral discs and uncovertebral joints and it should be taken into consideration when performing cervical traction in clinic.In addition,the traction angle should not be too large:0.-20. is generally recommended as a relatively safe angle range at the initial stage.

Biomechanical properties of cervical traction under neck muscle force / 医用生物力学

Objective To establish a three-dimensional(3D) finite element model of cervical vertebrae (C1-7),and study its biomechanical properties under muscle force by cervical traction,so as to provide references for clinical treatment.Methods On the basis of nonlinear finite element model of normal cervical vertebrae and combined with clinical traction methods,cervical traction at the extension angle of 0°,10°,20°,30°,40° under the same traction weight,was simulated by finite element analysis (FEA) software to obtain and select the joint force and muscle force that were appropriate for FEA on the model.Results In the process of cervical extension by traction,under the muscle force,the average maximum equivalent stress of cervical vertebrae,intervertebral disc and uncovertebral joints increased by 4.86,1.79,0.69 MPa,respectively,and the average maximum relative displacement of cervical vertebrae in sagittal and vertical axis direction increased by 1 1.1,1.26 mm,respectively.The biomechanical properties of cervical traction were similar to the FEA results reported in the literature.Conclusions Neck muscles play an active role in promoting the stress and displacement of cervical vertebrae,intervertebral discs and uncovertebral joints and it should be taken into consideration when performing cervical traction in clinic.In addition,the traction angle should not be too large:0.-20. is generally recommended as a relatively safe angle range at the initial stage.

Variation of neck EMG and mechanical characteristics during the process of cervical traction / 医用生物力学

Objective To observe changes of surface electromyography (sEMG) in cervical traction under different loading weight and at different angles, and compare the muscle activity changes obtained by experiment with simulation results obtained by AnyBody cervical modeling, so as to verify the rationality of the simulation results. Methods Ten young volunteers with supine cervical traction were selected to test the sEMG signals of bilateral sternocleidomastoid (SCM) and upper trapezius (UT) muscles by using the JE-TB0810 surface EMG device. The average EMG (AEMG) and mean power frequency (MPF) were used to analyze the variation patterns of sEMG in cervical spine. Results The AEMG values of SCM and UT muscles increased as the loading weight and traction angles increasing, with a statistically significant difference (P0.05). The experimental results were consistent with muscle force activity characteristics of SCM and UT muscles by modeling and simulation of cervical traction. Conclusions The simulation results are reasonable. The traction weight should be loaded reasonably according to the excitation and fatigue of the cervical muscles in clinic. This can both reach the treatment effect and improve the patient’s comfort, which will provide an important reference for further development and improvement of the cervical traction device.

Analysis of the causes of 117 infants with persistent hoarseness / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the causes of persistent hoarseness in infants.</p><p><b>METHODS</b>One hundred and seventeen infants with persistent hoarseness treated in the department of otorhinolaryngology in Children's Hospital of Fudan University between June 2008 and July 2010 were retrospectively analyzed (all patients received antibiotic therapy for 2 weeks and the symptoms were not relieved after that). The patients were divided into three groups according to the age at first visit: 22 newborns, < 6 months old in 60 cases, < 12 months old in 35 cases. All patients had video laryngoscope examinations. Some of them received CT scan, cardiac ultrasonography and pathological examination in additional. The diagnosis was established by clinical history and imaging modalities, and the causes were analyzed subsequently.</p><p><b>RESULTS</b>Among the 117 patients, 45 cases were vocal hypertrophy and hyperplasia (37.81%), 39 cases were vocal cord paralyses (32.78%), 7 cases were laryngeal hemangiomas (5.89%), 4 cases were laryngeal webs and cyst (3.36%), 2 cases were vocal cord polyps (1.68%), 2 cases were glottic incompetence (1.68%), 1 case was laryngeal papillomas(0.84%), 1 case was vocal code granulomas (0.84%), 1 case was glottis restricted by neck lymphangioma (0.84%); 4 cases were undetermined and 13 cases were no abnormalities. The percentage of patients with congenital heart diseases (19 cases) in vocal cord paralysis was 48.72%. The proportion of vocal cord paralysis in younger group was higher than that in elder one, their percentage were 50.00%, 36.67% and 17.14% respectively (χ(2) = 7.18, P < 0.05).</p><p><b>CONCLUSIONS</b>A variety of causes can lead to persistent hoarseness in infants. The majority of them are vocal hypertrophy and hyperplasia, followed by vocal cord paralyze. Vocal cord paralysis is more common in younger infants than in elder ones, and the main causes are post-cardiac surgery and congenital heart disease.</p>

Relationship between ultrasonographic velocimetric parameters and microvessel density in patients with papillary thyroid carcinoma and its clinical significance / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To determine the relationship between velocimetric parameters by using color Doppler ultrasonography and microvessel density (MVD) in papillary thyroid carcinoma and its clinical significance for preoperative diagnosis of papillary thyroid carcinoma. Methods Twenty-nine thyroid tumors were examined preoperatively by color Doppler ultrasonography. The velocimetric parameters including peak systolic velocity (V(max)), end-diastolic velocity (V(min)) were evaluated respectively and resistance index (RI) was calculated. Immunohistochemistry was applied by using polyclonal rabbit anti-human Von Willebrand factor in all cases after operation and microvessel density was calculated based on it.</p><p><b>RESULTS</b>Of the twenty-nine patients who underwent surgery, seventeen patients were diagnosed in papillary thyroid carcinoma and twelve patients in thyroid adenoma. In velocimetric analysis, the RI was significantly higher in patients with papillary thyroid carcinoma than those with thyroid adenoma (t = 3.3108, P < 0.01). V(max) and Vmin were no significance in those two tumors respectively (Z = 0.9520, P > 0.05; Z = - 1.6618, P > 0.05). MVD was also significantly increased in patients with papillary thyroid carcinoma (t = 8.1991, P < 0.01). There was a significant positive association between RI and MVD (r = 0.7924, P < 0.01).</p><p><b>CONCLUSIONS</b>Color Doppler ultrasonography could well display the blood flow of thyroid tissue and its nodules. The velocimetric parameter RI was higher in papillary thyroid carcinoma than in adenoma and was along with its MVD. RI may provide valuable information for diagnosis of papillary thyroid carcinoma preoperatively.</p>