【Abstract】 Objective To evaluate the feasibility and effectiveness of reconstruction of mandibular bone defects using three-dimensional skull model and individualized titanium prosthetics from computer assisted design. Methods Between July 2002 and November 2009, 9 patients with mandibular defects accepted restorative operation using individualized bone prosthetics. Among 9 cases, 4 were male and 5 were female, aged 19-55 years. The causes of mandibulectomy were benign lesions in 8 patients and carcinoma of gingival in 1 patient. Mandibular defects exceeded midline in 2 cases, involved condylar in 4 cases, and was limited in one side without involvement of temporo-mandibular joint in 3 cases. The range of bone defects was 9.0 cm × 2.5 cm-17.0 cm × 2.5 cm. The preoperative spiral CT scan was performed and three-diamensional skull model was obtained. Titanium prosthetics of mandibular defects were designed and fabricated through multi-step procedure of reverse engineering and rapid prototyping. Titanium prosthetics were used for one-stage repair of mandibular bone defects, then two-stage implant denture was performed after 6 months. Results The individualized titanium prosthetics were inserted smoothly with one-stage operative time of 10-23 minutes. All the cases achieved incision healing by first intention and the oblique mandibular movement was corrected. They all got satisfactory face, had satisfactory contour and good occlusion. In two-stage operation, no loosening of the implants was observed and the abutments were in good position with corresponding teeth which were designed ideally before operation. All cases got satisfactory results after 1-9 years of follow-up. At last follow-up, X-ray examinations showed no loosening of implants with symmetry contour. Conclusion Computer assisted design and three-dimensional skull model techniques could accomplish the design and manufacture of individualized prosthetic for the repair of mandibular bone defects.
Objective To precisely treat compl icated calcaneal fracture by 3D simulation through computer aid designed operation. Methods From November 2007 to March 2008, 38 patients of calcaneal fracture were treated. There were 29 males and 9 females aged 14-69 years old (average 29.8 years old). According to Sanders classification, there were 4 patients oftype I, 14 of type II, 12 of type III, and 8 of type IV. The time between injury and surgery was 3 hours to 5 days. The CT images of calcaneal fracture of 38 patients were put into computer for 3D reconstruction, then the Bouml;hler angles were measured and bone grafting angles were designed. According to the angle surveyed by the computer, the individual-oriented operation program was made, and then the operation was done under C-arm X-ray machine. Results The preoperative Bouml;hler angel was (34.58 ± 4.38)° in the normal side and (8.33 ± 12.62)° in the injured side, indicating there was significant difference (P lt; 0.05). During the process of the poking reduction by 3D simulation, when the bone rotating angle was (28.84 ± 6.51)°, the Bouml;hler angel was restored to (32.86 ± 1.72)°, indicating there was no significant difference when compared with the normal side before operation (P gt; 0.05), and significant difference compared with the injured side before operation (P lt; 0.05). Twenty-eight patients were followed up for 12-22 months (average 18 months). The Bouml;hler angel was restored to (32.41 ± 1.42)° 1 year after operation. According to the foot function scoring system made by American Ankle Surgery Association, 16 cases were graded as excellent, 10 as good, 1 as fair, 1 as poor, and the excellent and good rate was 92.9%. Conclusion Computer aid designed operation of compl icated calcaneal fracture by 3D simulation technique can restore the Bouml;hler angel and subtalar joint precisely. It is aneffective supplementary treatment method for calcaneal fracture.
目的 探讨64层螺旋CT最小密度投影（MinIP）结合CT仿真内窥镜（CTVE）对小儿支气管异物的应用价值。 方法 对2010年6月－2012年1月临床拟诊为气管支气管异物的48例患儿行64层螺旋CT检查同期行纤维支气管镜检查，分析64层螺旋CT MinIP结合CTVE等多种重建技术对小儿支气管异物显示情况，并与纤维支气管镜检查结果对照。 结果 MinIP结合CTVE技术诊断气管支气管异物28例，以纤维支气管镜为标准，敏感性93.33%，特异性94.44%，诊断准确率93.76%；两种方法对支气管异物的检出率比较其差异无统计学意义（χ2=0.174，P＞0.05）。 结论 MinIP结合CTVE技术是一种快速无创的检出方法，大大提高了小儿气管支气管异物的敏感性、特异性和检出率，对小儿气管支气管异物纤维支气管镜取出治疗有重要价值。
目的 探讨CT仿真内镜（CT virtual endoscopy，CTVE）在低位直肠癌术前分期中的价值。方法 收集我院2008年8月1日至2011年3月1日期间的直肠癌患者57例，术前行直肠CTVE检查，详细记录患者直肠癌周围组织浸润和淋巴结转移的情况；患者术后常规进行病理检查，比较两者结果的差异。结果 术前直肠CTVE检查与术后石蜡病理检查对直肠癌周围淋巴结转移的判断经四格表χ2检验，差异无统计学意义（χ2=2.5，P＞0.05），其对直肠癌周围淋巴结转移预测的敏感性为66.67%，特异性为93.94%。术前直肠CTVE预测直肠癌周围组织浸润和术后病理检查结果经四格表χ2检验，差异有统计学意义（χ2=4.4，P＜0.05），其对直肠癌周围组织浸润判断的敏感性为27.78%，特异性为42.86%。结论 CTVE在术前评估直肠癌周围淋巴结转移有较高的可信性，但对直肠癌周围组织浸润的评价较差。
ObjectiveTo study the clinical value of digital technology assisted minimally invasive surgery in diagnosis and treatment of hepatolithiasis. MethodsThe image data of 64-slice spiral CT scanning were obtained from five patients of complicated hepatolithiasis and introduced into medical image three-dimensional visualization system (MI-3DVS) for three-dimensional reconstruction. On the basis of the data of three-dimensional reconstruction, minimally invasive surgical planning of preoperation was made to obtain reasonable hepatectomy and cholangiojejunostomy, and then preoperative emulational surgery was carried out to minimize the extent of tissue damage and provide guidance to actual operation. ResultsLiver, biliary system, stone, blood vessel, and epigastric visceral organ were successfully reconstructed by MI-3DVS, which showed clearly size, number, shape, and space distribution of stone, and location, degree, length, and space distribution of biliary stricture, and anatomical relationship of ducts and vessels. The results of three-dimensional reconstruction were successfully confirmed by actual operation, which was in accordance with emulational surgery. There was no operative complication. No retained stone in internal and external bile duct was found by Ttube or other supporting tube cholangiography on one month after operation. ConclusionThree-dimensional digitizing reconstruction and individual emulational surgery have important significance in diagnosis and treatment of complicated hepatolithiasis by minimally invasive technique.
Pressure-support ventilation (PSV) is a form of important ventilation mode. Patient-ventilator synchrony of pressure support ventilation can be divided into inspiration-triggered and expiration-triggered ones. Whether the ventilator can track the patient's inspiration and expiration very well or not is an important evaluating item of the performance of the ventilator. The ventilator should response to the patient's inspiration effort on time and deliver the air flow to the patient under various conditions, such as different patient's lung types and inspiration effort, etc. Similarly, the ventilator should be able to response to the patient's expiration action, and to decrease the patient lung's internal pressure rapidly. Using the Active Servo Lung (ASL5000) respiratory simulation system, we evaluated the spontaneous breathing of PSV mode on E5, Servo i and Evital XL. The following parameters, the delay time before flow to the patient starts once the trigger variable signaling the start of inspiration, the lowest inspiratory airway pressure generated prior to the initiation of PSV, etc. were measured.
It is very difficult for stroke patients to complete the action of squatting-standing because their equilibrium function ability has been seriously declined. It was necessary, therefore, to do a deep research on the action of human squatting-standing and to set up an accurate model and simulation. In our modeling research, the movements of upper limbs and head was neglected, and a seven-segment model was developed to establish the coordinate system of human squatting-standing action. It calculated the knee joint moment and hip joint moment during squatting and standing by utilizing Lagrange method, and then simulated this mathematical model by utilizing Matlab. Geometric model of human squatting-standing was developed and simulated in ADAMS which proved that the established Lagrange model was reasonable. It would also provide significant theoretical references for further study and development of squatting-standing rehabilitation training equipment.
Pulse waves contain rich physiological and pathological information of the human vascular system. The pulse wave diagnosis systems are very helpful for the clinical diagnosis and treatment of cardiovascular diseases. Accurate pulse waveform is necessary to evaluate the performances of the pulse wave equipment. However, it is difficult to obtain accurate pulse waveform due to several kinds of physiological and pathological conditions for testing and maintaining the pulse wave acquisition devices. A pulse wave generator was designed and implemented in the present study for this application. The blood flow in the vessel was simulated by modeling the cardiovascular system with windkessel model. Pulse waves can be generated based on the vascular systems with four kinds of resistance. Some functional models such as setting up noise types and signal noise ratio (SNR) values were also added in the designed generator. With the need of portability, high speed dynamic response, scalability and low power consumption for the system, field programmable gate array (FPGA) was chosen as hardware platform, and almost all the works, such as developing an algorithm for pulse waveform and interfacing with memory and liquid crystal display (LCD), were implemented under the flow of system on a programmable chip (SOPC) development. When users input in the key parameters through LCD and touch screen, the corresponding pulse wave will be displayed on the LCD and the desired pulse waveform can be accessed from the analog output channel as well. The structure of the designed pulse wave generator is simple and it can provide accurate solutions for studying and teaching pulse waves and the detection of the equipments for acquisition and diagnosis of pulse wave.
In this study, a closed-loop controller for chest compression which adjusts chest compression depth according to the coronary perfusion pressure (CPP) was proposed. An effective and personalized chest compression method for automatic mechanical compression devices was provided, and the traditional and uniform chest compression standard neglecting individual difference was improved. This study rebuilds Charles F. Babbs human circulation model with CPP simulation module and proposes a closed-loop controller based on a fuzzy control algorithm. The performance of the fuzzy controller was evaluated and compared to that of a traditional PID controller in computer simulation studies. The simulation results demonstrated that the fuzzy closed-loop controller produced shorter regulation time, fewer oscillations and smaller overshoot than those of the traditional PID controller and outperforms the traditional PID controller in CPP regulation and maintenance.