To investigate the effects of augmentation with bone cement on the biomechanics of the dynamic hip screw (DHS) fixation in the intertrochanteric fracture specimen that has a normal bone density.MethodsTwentyfour matched pairs of the embalmed male upper femora (48sides) were used to make the specimens of the intertrochanteric fracture of Type A2. All the specimens were fixed with DHS. The right femur specimen from each pair was fixed by augmentation with DHS (the augmentation group) and the left femur specimen was fixed with the conventional fixation (the control group). Thebiomechanical tests on the bending stiffness and the torsional stiffness were performed with the servohydraulic testing machine in the two groups.ResultsThe maximum load and the maximum torque were 3 852.160 2±143.603 1 N and 15.5±2.6 Nm in the augmentation group and 3 702.966 7±133.860 1 N and 14.7±3.4 Nm in the control group. There was no significant difference in the biomechanical effects between the two groups (P＞0.05). Conclusion The augmenting fixation with bone cement in the intertrochanteric fracture specimen with a normal bone density has no significant effect on the strength of the DHS augmentation or on the overall stability of the fractured bone.
ObjectiveTo review the research status in respect of interspinous distraction devices (IDD) in the treatment of degenerative lumbar spinal stenosis (DLSS). MethodsRecent original articles related to IDD in the treatment of DLSS were retrieved extensively, and the effectiveness was analyzed and summarized. ResultsIts short-term effectiveness was superior to that of conservative treatment, no significant difference was found when compared with decompression or fusion alone. Its complication rate was higher than that of decompression or fusion alone, although complication dose not significantly affect treatment results, it still will increase the medical care cost of patients. ConclusionIDD is appropriate for patients who have failed to nonoperative treatment measures and can not tolerate open surgery, but the long-term effectiveness and durability of IDD need further research.
OBJECTIVE: To study the changes of neural electrophysiology properties of cauda equina under double level compression and dynamic burdens, and to clarify the mechanisms of intermittent neurogenic claudication. METHODS: Thirty SD rats were divided into 5 groups (6 in each group). The laminectomy of L5 was performed in control group. In the experimental groups, the silicon sheets were inserted into the spinal canal of L4 and L6 to cause double level compression of cauda equina by 30%. Two hours after onset of compression, no dynamic burden was introduced in experimental group 1. Only high frequency stimulation(HFS) was introduced for 6 minutes in experimental group 2. Both HFS and additional increased compression were introduced for 6 minutes in experimental group 3. While only additional increased compression was introduced for 6 minutes in experimental group 4. After 6 minutes of dynamic burdens, all were returned to the status of static compression for another 30 minutes and then electrical examination was made. RESULTS: After 2 hours of compression, motor and sensory nerve conduction velocity (NCV) of all the four experimental groups decreased significantly (P lt; 0.05), but there was no significant difference between them. There was no significant change in the control group. There was no significant change of NCV in experimental group 1 during the last 30 minutes of experiment. NCV in the other three experimental groups decreased after introduction of dynamic burdens, especially in the experimental group 3. CONCLUSION: The above results showed that NCV of cauda equina decreased significantly under dynamic burdens during static compression. Two kinds of dynamic burdens introduced at the same time can cause more profound change than a single one.
Objective To study the technique and effect of adjunctive cancellous screw in treatment of intertrochanteric fractures with dynamic hi p screw (DHS) fixation. Methods Between April 2004 and August 2007, 33 patients with intertrochanteric fracture were treated with DHS fixation and adjunctive cancellous screw. There were 13 males and 20 females, aging 43-82 years with an average age of 67 years. Fractures were caused by traffic accident in 7 patients, by fall ing from height in 11 patients, by sprain in 15 patients. All fractures were closed. The patients were operated 3-12 days after injury. According to Evans classification, there were 12 cases of type II, 15 cases of type III, and 6 cases of type IV. Twenty-twocases had osteoporosis. Weight bear time and compl ication were recorded. Fracture heal ing and neck-shaft angle were observed on radiogram. Hip functions were evaluated using Radford criterion. Results Thirty-three patients had no intraoperative compl ications with incision heal ing by first intension. All patients were followed up from 14 months to 38 months, with an average of 21 months. Fracture heal ing was achieved within 14 weeks to 21 weeks, with an average of 17 weeks after operations. The neck-shaft angles were (134.2 ± 13.7)° 3 days after operation, (128.6 ± 8.9)° 8 weeks after operation, and (128.5 ± 9.3)° after fracture heal ing, showing no significant difference when compared with that of the third day after operation (P gt; 0.05). According to the Radford criterion at last follow-up, the excellent and good rate of hi p function was 93.9% (excellent in 21 cases, good in 10 cases, and poor in 2 cases). Compl ications such as loosening, breakage, or grievous migration of hardware were not observed. Conclusion The adjunctive cancellous screw in treatment of intertrochanteric fractures with DHS fixation can provide counteraction of tension and rotation, promote fixation stabil ity, enhance fracture heal ing and decrease compl ication.
ObjectiveTo compare the clinical effects of early dynamic brace passive activity program and average delay activity program after the repair of extensor tendon. MethodsSeventy-eight patients undergoing repair of the extensor tendon during the period from December 2008 to October 2011 in our hospital were randomly divided into two groups.The treatment group had 36 patients who were treated with early dynamic brace passive activity program,and the other 42 patients belonged to the control group and they accepted delay activity program.TAM and FIM were used to evaluate their clinical effects six and eight weeks after surgery,respectively. ResultsThe results of TAM and FIM of the treatment group were significantly better than those of the control group (P<0.01). ConclusionThe early dynamic brace passive activity after extensor tendon injury repair can improve the clinical effect and is worth popularizing.
Objective To gain accurate imaging information of biliary tract after surgery. MethodsThe biliary tract of 170 cases after surgery had been observed dynamically from different directions for longer time. The results of data on biliary tract change were stored in disc, or picture. ResultsOf 170 cases, 120 cases were cured without any abnormal change on cholangiography, and then the Ttube was removed. Of another 50 cases, 30 cases revealed remnant stone on cholangiography, 9 cases showed inflammatory stricture of biliary tract, 4 cases displayed common bile duct tumor, and 7 cases had false fillingdefect. Then, the results were further confirmed by sonography, CT, choledochoscopy, and operation. Conclusion The dynamic observation of biliary tract by Ttube cholangiography after surgery is usual way that is handy, practical, painless, and economic.
ObjectiveTo evaluate the accuracy of the new dynamic approach in the measurement of respiratory mechanics with different pressure support (PS) level during pressure support ventilation (PSV) via oral-nasal mask.MethodsThe Respironics V60 ventilator was connected to a ASL5000 lung simulator, which simulate lung mechanics in patients with chronic obstructive pulmonary disease ［system compliance (Crs)=50 mL/cm H2O, airway resistance (Raw)=20 cm H2O/(L·s), inspiratory time (TI)=1.6 s, breathing rate=15 beats per minute］. PSV were applied with different levels of PS ［positive end-expiratory pressure=5 cm H2O, PS=5/10/15/20/25 cm H2O) and back-up rate=10 beats per minute］. Measurements were conducted at system leaks with 25 – 28 L/min. The performance characteristics and patient-ventilator asynchrony were assessed, including flow, airway pressure, time and workload. Crs and Raw were calculated by using new dynamic approach.ResultsTidal volume (VT) was increased with increasing PS level ［(281.45±4.26)mL at PS 5 cm H2O vs. (456.81±1.91)mL at PS 10 cm H2O vs. (747.45±3.22)mL at PS 20 cm H2O, P<0.01］. Severe asynchronous was occurred frequently when PS is at 25 cm H2O. Inspiration cycling criterion (CC) was up-regulated accompanied by increasing PS level ［(15.62±3.11)% at 5 cm H2O, vs. (24.50±0.77)% at 20 cm H2O, P<0.01］. Premature cycling was always existed during PSV when PS < 20 cm H2O, which could be eliminated as PS level increasing. Delay cycling was found when PS was at 20 cm H2O, and cycling delay time was (33.60±15.91)ms (P<0.01). The measurement of Crs was (46.19±1.57)mL/cm H2O with PS at 10 cm H2O, which was closer to the preset values of simulated lung. The underestimate of Crs was observed during high level PS support. The calculation of inspiratory and expiratory resistance was approximate to 20 cm H2O/(L·s) when PS level was exceeded 15 cm H2O.ConclusionsThe new dynamic approach can continuously assess the respiratory mechanics during non-invasive ventilation, which is no need to interrupt the patient's spontaneous breathing. Higher inspiratory flow during PSV is beneficial for Raw measurement, whereas the accuracy of Crs was influenced by the value of actual VT.
Objective To improve the knowledge on dynamic benign central airway stenosis through two typical cases. Methods The clinical features, imaging findings, and bronchial morphologic changes of two cases characterized by dynamic benign central airway stenosis were retrospectively analyzed. The etiologies for the two cases were tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC), respectively. Results Central airway stenosis and reversible airway obstruction were common clinical characteristics for the two cases. However, there were identifiable differences on imaging findings and bronchial morphologic changes between the two cases. Multidetector computed tomography showed sabre-sheath trachea and narrowed trachea in coronal position for TBM, while small sized trachea in exhalation phase and narrowed trachea in sagittal position for EDAC. Bronchoscopy displayed narrowed airway, swelling mucosa, and the absence of annular cartilage for TBM, while crescent airway with membranacea part protruding to lumen in inspiration phase, and the integrity of annular cartilage for EDAC. Conclusion Multidetector computed tomography and bronchoscopy examinations are valid methods to distinguish TBM and EDAC, which are both characterized by dynamic benign central airway stenosis.
Objective To study the changes of blood flow of the already-compressed cauda equina under dynamic burden, high frequency stimulation (HFS) and increased additional compression, and to clarify the mechanism of neurogenic intermittent claudication. Methods Thirty SD rats were divided into 5 groups, 6 in each. All groups were operated with laminectomy of the fifth lumbar verfebra. One hour after the measurement of blood flow,in 4experimental groups, the silicon sheets were inserted into the spinal canal of L4 and L6 to cause double level compression of cauda equina by 30%. Two hours after onset of compression, no dynamic burden was introduced to the subjects of the experimental group 1. Only HFS was introduced to the subjects of the experimental group 2 for 6 minutes. Both HFS and increased additional compression were introduced to the subjects of the experimental group 3 for 6 minutes. While only increased additional compression was introduced to the subjects of the experimental group 4 for 6 minutes. The subjects of control group only underwent laminectomy of the fifth lumbar vertebra and HFS 6 minutes. The blood flow of cauda equina was measured with laser Doppler flowmeter. Results In the first 2 hours, there was no significant change of cauda equina blood flow in the control group. During the time of HFS, the blood flow increased significantly to 186.4%±31.5% of initial value (Plt;0.05). In the experimental group 1, there was no blood flow change during the period of dynamic burden（110.4％±7.5％，Pgt;0.05）. After introduction of dynamic burden, there was no blood flow changes in the experimental group 2 (111.6％±17.6％，Pgt;0.05). The blood flow in the experimental group 3 decreased to 65.3%±10.7% of initial value (Plt;0.05); and the blood flow in the experimental group 4 decreased to 60.1%±9.2% of initial value (Plt;0.01). There was no significant difference between the experimental groups 3 and 4 (Pgt;0.05). Conclusion The results above show that during the period of increased impulse transmission, double level compression of cauda equina may limit the increase of blood flow, which maycause relative ischemia. If there is increased additional compression along with increased impulse transmission, the blood flow will decrease significantly, which will cause absolute ischemia.
Objective To investigate the development of dynamic hipscrew (DHS) internal fixation in the treatment of intertrochanteric femur fractures. Methods The latest relevant articles were reviewed extensively, including biomechanics and clinical application research. Results DHS is the effective selection for the treatment of intertrochanteric femur fractures, especially by the innovation of DHS structure, operative manipulation.Conclusion Treatment of intertrochanteric femur fractures with DHS is still a gold level, but strict selection of patients, proficiency operation and invasive manipulation are the most essential principles.