ObjectiveStudy how to quantify the bias of each study and how to estimate them. MethodIn the random-effect model, it is commonly assumed that the effect size of each study in meta-analysis follows a skew normal distribution which has different shape parameter. Through introducing a shape parameter to quantify the bias and making use of Markov estimation as well as maximum likelihood estimation to estimate the overall effect size, bias of each study, heterogeneity variance. ResultIn simulation study, the result was closer to the real value when the effect size followed a skew normal distribution with different shape parameter and the impact of heterogeneity of random effects meta-analysis model based on the skew normal distribution with different shape parameter was smaller than it in a random effects metaanalysis model. Moreover, in this specific example, the length of the 95%CI of the overall effect size was shorter compared with the model based on the normal distribution. ConclusionIncorporate the bias of each study into the random effects meta-analysis model and by quantifying the bias of each study we can eliminate the influence of heterogeneity caused by bias on the pooled estimate, which further make the pooled estimate closer to its true value.
Objective To investigate the causes of visual loss and failure of treatment after intraocular silicone oil removal. Methods Retrospective clinical analysis of the causes of loss of visual acuity of 15 eyes after silicone oil removal in patients with complicated retinal detachment which were successfully treated with vitreous and retinal microsurgery. Results Among the 15 eyes,retina failed to reattach in 11 eyes,secondary glaucoma occurred in 2 eyes and corneal opacity appeared in another two eyes.All of them were resulted in total loss of vision. Conclusion Retinal redetachment was the leading cause of final visual loss in the failing 15 cases(15 eyes) after intraocular silicone oil removal,and secondary glaucoma and corneal decompensation may also be the causes of visual loss. (Chin J Ocul Fundus Dis, 1999, 15: 230-231)
With the progresses of the research on "Digital Human", more and more information has been needed for the setting up of the three-dimensional digital models of human organs. In the present paper, based on the method of block mapping with a normal-style bump mapping method, we normalized the vector of the surface of the models, computed offset of the texture coordinates and added to them. The projection of the coordinates to the tangential space complemented the disturbance to the vector of models' surface. The method was proposed with bump texture mapping on the surface of the biological models of organs to improve the impression of the visualization of the organ models and to enhance the sense of reality of the models.
ObjectiveTo investigate the clinical value of cervical vascular color Doppler ultrasound for dignosis of nonrecurrent laryngeal nerve before thyroid surgery. MethodsThere were 1931 cases of thyroid patients treated between January 2010 to Jule 2014, group these patients according to the results of preoperative chest radiograph examination, the chest radiograph shows abnormal vessels image were group A (45 cases), no abnormalities were group B (1886 cases). Before operaton, made patients of group A to have routine carotid duplex ultrasound to identify whether the right subclavian artery abnormalities. All patients were exposed to conventional methods of recurrent laryngeal nerve during surgery. ResultsThe 45 patients of group A, chest angiography showed 17 cases with right subclavian artery abnormalities, they were confirmed that all the 17 patients were nonrecurrent laryngeal nerve by surgery, no damage cases. The other 28 cases showed a normal right subclavian artery and no cases of nonrecurrent laryngeal nerve. The 1886 patients in group B, surgical exploration found four cases with nonrecurrent laryngeal nerve, injury in 1 case. The 21 patients whose nonrecurrent laryngeal nerve were on the right side, there were no left side with nonrecurrent laryngeal nerve and no co-exist cases of nonrecurrent and recurrent laryngeal nerve. The average exposure time of nonrecurrent laryngeal nerve in patients of group A (17 cases) was significantly shorter than that group B[(4.28±1.08) min vs. (15.50±2.08) min, t=-15.978, P=0.000]. ConclusionsThe cervical vascular color Doppler ultrasound examination before thyroid surgery can be adjuvant used, if there is the right subclavian artery abnormalities, it showes that there is the right side nonrecurrent laryngeal nerve. So as to effectively prevent the damage of nonrecurrent laryngeal nerve during thyroid surgery.
ObjectiveTo investigate the method and effectiveness of selectively upward placement of acetabular implants in patients with anatomically abnormal acetabulum during total hip arthroplasty (THA). MethodsTwenty-six cases (26 hips) of anatomically abnormal acetabulum received THA between January 2005 and December 2010, including 22 cases of developmental dysplasia of the hip, 3 cases of osteonecrosis of the femoral head, and 1 case of post-traumatic arthritis. There were 5 males and 21 females with an average age of 52.3 years (range, 35-67 years). The left hip was involved in 11 cases and the right hip in 15 cases. The preoperative Harris score was 45.85±10.04. The anteroposterior X-ray films and CT scan of the pelvis, anteroposterior and lateral X-ray films of the femur, and TraumaCad analysis were performed routinely before operation. The principles of acetabular implants were that more than 70% of the bone-implant interface was covered, and the upward distance of acetabular implant was less than 15 mm. ResultsAcetabular implants were placed within 5 mm from the anatomical rotation center in 11 cases. The upward distance of acetabular implant was 5-10 mm in 8 cases and was 10-15 mm in 7 cases. No bone fracture or nerve injury was observed intraoperatively. All incisions healed by first intention, and no infection or lower limb deep venous thrombosis occurred. One case had dislocation at 3 days after operation, and was cured after reduction and conservative treatment. The follow-up time ranged from 15 to 71 months (mean, 34 months). The Harris score was 91.42±3.59, showing significant difference when compared with preoperative score (t=20.099, P=0.000). The Harris scores were 92.09±4.04 in patients having less than 5 mm upward distance, 91.25±2.82 in patients having 5-10 mm upward distance, and 90.57±3.95 in patients having 10-15 mm upward distance, showing no significant difference (F=0.377, P=0.690). No loosening or subsidence of the implant was observed by X-ray film during the follow-up. ConclusionThe acetabular implants should be placed as close to anatomical rotation center as possible according to the principle. However, appropriate upward distance of the acetabular implants (≤15 mm) could be acceptable to meet 70% coverage of bone-implant interface and the implant stability. A satisfactory mid-term effectiveness can be obtained, but long-term effectiveness should be further investigated.
Objective To observe the decline ratio of FEV1 after inhaling 0. 9% saline to the baseline, and to explore its relation to the result of bronchial provocation test ( BPT) with methacholine.Methods 115 patients with chronic cough or chest tightness were collected in Shougang Hospital, Peking University from March 2008 to September 2009. They were all performed pulmonary function test and the decline ratio of FEV1 after inhaling 0.9% saline to the baseline( ΔFEV1 ) was measured. Then they were allperformed BPT with methacholine. The predictive value of ΔFEV1 measurement for BPT results was evaluated. Results 49 cases yielded positive results in methacholine BPT, with ΔFEV1 gt; 3% in 35 cases and gt;5% in 20 cases. 66 casess yielded negative results in methacholine BPT, with ΔFEV1 gt; 3% in 6 cases. The sensitivity and specificity were 71% and 91% respectively when ΔFEV1 gt;3% was set as a cutoff,and which were 40. 8% and 100% respectively when ΔFEV1 gt;5% was set as a cut-off. All the patients didn’t show any serious adverse reaction. Conclusion ΔFEV1 gt;3% after inhaling 0. 9% saline is a good predictor for BPT results. More caution should be paid to these patients when performing BPT.
For the detection and identification of abnormal nodular tissues on the body surface, a microwave sensor structure loaded with a spiral resonator is proposed in this paper, a sensor simulation model is established using HFSS software, the structural parameters are optimized, and the actual sensor is fabricated. The S21 parameters of the tissue were obtained when nodules appeared by simulation, and the characteristic relationship between the difference of S21 parameters with position was analyzed and tested experimentally. The results showed that when nodules were present in normal tissues, the curve of S21 parameter difference with position change had obvious inverted bimodal characteristics, and the extreme value of S21 parameter difference appeared when the sensor was directly above the nodules, which was easy to identify the position of nodules. It provides an objective detection tool for the identification of abnormal nodular tissues on the body surface.
Objective To investigate the morphological anatomical abnormal ities of high congenital dislocation of hip in adults and provide anatomical basis for the total hip arthroplasty (THA). Methods From May 1997 to July 2008, 49 patients (57 hi ps) with high congenital dislocation of hip (Hartofilakidis type III) were treated. There were 6 males and 43 females with an average age of 29.4 years old (18-56 years old). The locations were left in 24 hi ps and right in 33 hi ps. The morphological parameters (including femoral length, isthmus, height of femoral head center, neck-shaft angle, medialhead offset, anteversion angle, canal flare index, anteroposterior diameter of the true acetabulum, posterior thickness of the true acetabulum, depth of the true acetabulum) of suffering hips (dislocation group, n=57) were measured by preoperative X-ray, CT and intraoperative cl inical observation and were compared with those of contralateral hips (control group, n=41). The intraoperative situations of hip were observed. Results The height of dislocation was (45.41 ± 2.15) mm. The length difference of both lower extremities was (40.41 ± 2.02) mm. In dislocation group, isthmus was shortened; height of femoral head center, neck-shaft angle and medial head offset were decreased; and anteversion angle was increased. CT showed that the canal flare index was larger than 4.7, femoral shape was funnel-shaped according to Noble classification. Anteroposterior diameter of the true acetabulum became smaller, posterior thickness of the true acetabulum became thicker, and depth of the true acetabulum was shallower. There were statistically significant differences in the morphological parameters of femur and acetabulum between two groups (P lt; 0.05). The intraoperative measurements showed that the anteroposterior diameter of acetabulum was (32.98 ± 1.02) mm and the depth of acetabulum was (14.21 ± 0.56) mm. There was no statistically significant difference between intraoperative measurements and preoperative measurements (P gt; 0.05). The acetabulum was full of fat and fibrous tissues. Running of the sciatic nerve in 40 cases were changed and it ran upward and laterally. Conclusion When high congenital dislocation of the hip in adults is treated with THA, anatomical variation must be fully taken into account. The acetabulum is expanded toward posterosuperior, excessive reamed should be avoided to prevent femoral fractures, and appropriate or tailor-made prosthesis was selected.
ObjectivePulmonary infection is commonly seen in patients with rheumatic autoimmune disease (RAD).Sometimes bronchoscopy is used to obtain microorganisms.In order to improve diagnostic yield, the factors affecting diagnostic yield of bronchoscopy in obtaining microorganisms in RAD patients with pulmonary abnormality were analyzed retrospectively. MethodsA retrospective study was performed in RAD patients with lung infiltrates who received bronchoscopy for obtaining microorganisms at the Department of Rheumatology,Peking Union Medical College Hospital from January 2009 to June 2013.Patients characteristics,clinical symptoms,medication history,laboratory parameters,radiographic findings and locations where microorganisms were obtained were recorded. Results87 patients received 91 bronchoscopic exams,including 72 bronchoalveolar lavages,21 bronchial aspirates,and 72 bronchial brushes.The total diagnostic yield was 52.7%.The diagnostic yield was 71.4% with bronchoalveolar lavage,38.9% with bronchial aspirate,and 18.1% with bronchial brush.Diagnostic yield was significantly higher in the patients with clinical symptoms of fever,cough or expectoration compared with the patients without either symptoms (60.0%% vs.34.6%,P=0.028).The patients with CT finding of nodular,massive or consolidation had a higher diagnostic yield compared with those with CT findings of reticular,linear or ground glass opacity (61.8% vs.26.1%,P=0.003).Diagnostic yield was not affected by location of bronchoalveolar lavage (P=0.691). ConclusionRAD patients with fever,cough or sputum,and CT findings of nodular,massive or consolidation would get a higher diagnostic yield by bronchoscopy.
On account of the mechanical disturbance of external chest pressing to electrocardiogram (ECG) signal, the ECG rhythm cannot be identified reliably during the cardio-pulmonary resuscitation period. Whereas the possibility of successful resuscitation will be lowered due to interrupted external chest pressing, a new filtering algorithm, enhanced leastmean-square (eLMS) algorithm, was proposed and developed in our laboratory. The algorithm can filter the disturbance of external chest pressing without the support of hardware reference signal and correctly identify ventricular fibrillation (VF) rhythm and normal sinus rhythm in case of uninterrupted external chest pressing. Without other reference signals, this algorithm realizes filtering only through the interrupted electrocardiograma (cECG) signal. It was verified with ECG signal and disturbance signal under different signal to noise ratios and contrasted with other mature algorithms. The verification results showed that the identification effect of eLMS was superior to those of others under different signal to noise ratios. Furthermore, ECG rhythm can be correctly identified only through cECG signal. This algorithm not only reduces the research and development(R & D)costs of automated external defibrillator but also raises the identification accuracy of ECG rhythm and the possibility of successful resuscitation.