Robot-assisted surgery is becoming a widely popular technology and now entering total knee replacement. The development of total knee replacement is introduced in this paper with the emphasis on femur positioning technologies. The experiments and error analysis of robot-assisted surgical system for total knee replacement demonstrate that femur positioning technologies have a high precision and thus deserve to be popularized theoretically and practically.

BACKGROUND: There are many methods for investigating the physical development and the somatotype of child. Among them, Heath-Carter so matotype method is a comprehensive evaluation method on somatotype. In this method, 10 items of anthropometric indicators are selected from several dozens of items as assessment indicators for development and somatotype.OBJECTIVE: To analyze the rules and characteristics of soma totype development of Hah children in rural area of Huludao city, so as to supplement the essential data for physical anthropology.DESIGN: Normal children were chosen as the subjects, and cross-sectional investigation was carried out.SETTING: Department of Anatomy, Jinzhou Medical College. PARTICIPANTS: With cluster sampling, the Han children between 7 to 10 years old were selected from central primary school of Mingshuixiang Village of Suizhong County of Huludao city from July 2001 to September 2003. All the selected children should be verified healthy by physical examination at school. The children were divided into two groups according to gender, and each group was divided into 4 subgroups according to age,with 46 to 63 members in each group. There were 8 groups altogether.Complete data of 408 children were collected (male 213, female 195).METHODS: Each indicator was measured twice with Heath-Carter soma to type method and selected the average value. Specialists were responsible for the 10 indicators, and a database was established in computer according to age and gender. Calculated the following indicators in turn: endomorphic factor, mesomorphic factor and ectomorphic factor, coordinate values of X and Y on somatotype chart, Height/Weight1/3, mean of dimensional distances from the average somatotype to all somatotypes in the sample,difference between the two somatotypes in three-dimensional space, percentage of body fat and frequency distribution of each somatotype.MAIN OUTCOME MEASURES: Height, body mass, upper arm circum ference, calf circumference, intracondylar diameters of humerus and femur,skinfold of brachial triceps, subscapular skinfold, skinfold of anterosuperior iliac spine, skinfold of gastrocnemius muscle.RESULTS: All the 408 children entered results analysis. ①Height and body mass of 7 to 10 year old children increased as age went up, indicators of Height/Weight1/3 of 7,8,10 year old girls were higher than boys, that of 9 years old boys was higber than girls, which were related to that the growth of height of 8 & 9 year old boys (5.61 cm) was more than girls (3.88 cm).The content of body fat of girls was more than boys. The 3 somatotype values were 3.2-3.9, 2.3-2.6 and 3.0-3.4 in boys and 3.5-4.6, 1.9-2.6 and 3.3-3.5 in girls, so endomorphic factor and ectomorphic factor were the main factors both in girls and boys, and endomorphic gene in girls was higher than boys, which indicated that the content of body fat of rural children in Hulutao city was relatively high, their bodies were finely high and thin, their skeletal muscle was not so muscular and the hypodermic fat in girls was more abundant. Seen from the comparison of somatotype between boys and girls in each age group, the differences between two somatotypes in the three dimensional space of 7-, 8-, 9-, 10-11 year old groups were 0.46, 0.68, 1.03 and 0.61 respectively, except 7-year old group, there were significant differences in somatotype of boys and girls between each age groups (P ＜ 0.01). ②The average value of somatotype of Han boys in rural area was 3.4-2.5-3.2, which belonged to medial type; that of girls was 4.0-2.3-3.4, which beglonged to ectomorphic endomorphic type. Endomorphic factor and ectomorphic factor were the dominant factors both in boys and girls, whereas mesomorphic factor was relatively low; the frequency of somatotype kept changing as the increase of age. ③Compared with the data at home and abroad, the endomorphic factor of the Han children in rural area in Huludao City was relatively high, while the mesomorphic factor was relatively low, and the ectomorphic factor was almost the same.CONCLUSION: The somatotype of Han children in rural area in Huludao City develops better. Their heights are tall, whereas their skeletal muscles are not so muscular. Somatotype development of children is diversified with age.

Objective To investigate the clinical characteristics and emergency management of severe hand-foot-mouth disease(HFMD)associated with encephalitis and neurogenic pulmonary edema(NPE)caused by en-terovirus 71(EV71)in children.Method Data of critical patients with severe HFMD associated with encephalitis and NPE admitted to pediatric intensive care unit(PICU)Fuyan city Hospitals Anhni Province from May to June 2008 were reviewed.Results Of 30 patients,the mean age was 15.8 months ranged from 4 months to 48 months.The overall morality was 19.4%.Tha average duration of critical symptoms persisted Was 2.1 days ranged from 12 hours to 5 days.There were no rash found in 12 patients(33.3%).The chinical features of nervous system mani-fested the symptoms of brainstem encephalitis in 27 patients(75%),brainstem encephalitis with myelitis in 6 pa-tients(16.7%),and encephalitis in 3 patients(8.3%).The frothy expectoration tinged with pink or bloody,asyrmmetrical pulmonary edema or hemoptysis were the main features of NPE.The main approaches to the treatment were mechanical ventilation,mannitol,methylpredifiselone,intravenous immunoglobulin(IVIG),and vasoactive a-gents.And nine patients(25%)needed fluid volume resuscitation in addition.Conclusions Young children are particularly vulnerable to the Severe EV71 encephalitis with NPE.The majority of involved fatal patients are aged under 3 years.Patients may die of acute onset of NPE and/or hemoptysis with rapid progress towards cardiopul-monary failure.Early diagnosis and evaluation,respiratory support,lowering intracranial pressure and maintaining hemodynamics ale the essential therapeutic approaches.

Determination of femoral anatomic axis plays an important role in robot-assisted surgery of total knee replacement. In traditional total knee replacement surgery, the axis is obtained by inserting a rod into femoral lumen. However, in the robot-assisted total knee replacement based on CT model. the femoral anatomic axis must be determined preoperatively. Because the lengths in femurs are quite different in different patients, besides noises, the upper segment and lower segment of the femur influence the design of the axis greatly. Traditionally, the femoral anatomic axis is obtained by using the least-squares method directly. However, this method is easily disturbed by noise. To avoid the noise disturbance of CT data, the least median of squares method is used to fit the femoral anatomic axis for its characteristic of robust regression. The least median squares method eliminates the disadvantage brought by the method of least squares. In finding the best-fit line, genetic algorithms are used in the paper. In our experiment, we use the proposed method to fit the femoral anatomic axis and obtain an excellent result.
Algorithms ; Arthroplasty, Replacement, Knee ; methods ; Femur ; anatomy & histology ; diagnostic imaging ; surgery ; Humans ; Robotics ; Surgery, Computer-Assisted ; instrumentation ; methods ; Tomography, X-Ray Computed

Robot assisted surgery is becoming a widely popular technology and is now entering the total knee replacement. The development of total knee replacement and the operation system structure are introduced in this paper. The vision position technology and the related calibration technology, which are very important, are also analyzed. The experiments of error analysis in our WATO system demonstrate that the position and related calibration technologies have a high precision and can satisfy surgical requirement.
Arthroplasty, Replacement, Knee ; instrumentation ; methods ; Humans ; Pattern Recognition, Automated ; methods ; Robotics ; instrumentation ; Surgery, Computer-Assisted ; instrumentation ; methods

Objective:To investigate the application value of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in evaluating flow diverter (FD) apposition and endothelialization in aneurysm animal models, and analyze the effect of incomplete stent apposition (ISA) on aneurysm lumen healing and stent endothelialization.Methods:Lateral common carotid artery aneurysm models in swines were established by surgical method and then FD was implanted. Immediately after surgery, OCT and IVUS were used to evaluate the locations and degrees of ISA, and difference between these 2 methods in evaluating FD apposition was compared. DSA was performed at 12 weeks after surgery to evaluate the aneurysm occlusion (Kamran grading) and stent patency. OCT and IVUS were used again to observe the stent endothelial situation; by comparing with histopathologic results, effect of ISA on aneurysm healing and stent endothelialization was analyzed.Results:Lateral common carotid artery aneurysm models in 6 swines were established, and 6 Tubridge FDs were successfully implanted. Compared with IVUS (3 stents, 4 locus), OCT could detect more ISA (6 stents, 14 locus); and the vascular diameter change area (7 locus), aneurysm neck area (4 locus) and the head and tail of FD (3 locus) were the main sites of FD malapposition; average distance between stent wire and vessel wall was (560.14±101.48) μm. At 12 weeks after surgery, DSA showed that 1 patient had a little residual contrast agent at the aneurysm neck (Kamran grading 3), and the remaining 5 had complete aneurysm occlusion (Kamran grading 4). One FD had moderate lumen stenosis, and the other 5 FDs had lumen patency. OCT indicated mostly disappeared acute ISA; ISA proportion decreased to 21.4 % (3/14), including 2 in the aneurysm neck and 1 in the partial stent. Histopathological results showed bare stent woven silk, without obvious endothelial coverage; in one FD with luminal stenosis, intimal hyperplasia was mainly composed of vascular smooth muscle cells.Conclusion:In carotid artery aneurysm model with FD implantation, OCT can detect more ISA than IVUS; most acute ISA have good outcome at 12 th week of follow-up, while severe ISA can cause delayed FD endothelialization and delayed aneurysm occlusion.