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find Author "ZHANG Kai" 25 results
  • Efficacy and predictive factors analysis of vagus nerve stimulation in patients with refractory MRI-negative epilepsy

    ObjectiveTo investigate the efficacy of vagus nerve stimulation (VNS) in patients with refractory magnetic resonance imaging (MRI)-negative epilepsy and to evaluate potential clinical predictors. MethodsA retrospective collection of efficacy data was conducted on 24 patients with intractable MRI-negative epilepsy treated with VNS, who were followed up for more than six months, at Beijing Tiantan Hospital and Beijing Fengtai Hospital from January 2016 to September 2023. Patients were divided into two subgroups based on their response to VNS: responders (≥50% reduction in seizure frequency) and non-responders (<50% reduction in seizure frequency). The relationship between preoperative clinical data and VNS efficacy was further analyzed to identify potential predictors of VNS efficacy. ResultsA total of 24 patients were included, with an average age of (14.26±8.39) years old. Seizure frequency was reduced by more than 50% in 37.5% of patients, and 8.3% of patients achieved seizure-free after VNS treatment. Preoperative seizure frequency and interictal epileptiform discharge type were significantly associated with VNS efficacy (P<0.05). Multivariate regression analysis showed that a monthly seizure frequency of less than 100 and focal interictal epileptiform discharges were independent predictors of VNS efficacy (P<0.05). ConclusionVNS is an effective treatment for patients with refractory MRI-negative epilepsy. Lower monthly seizure frequency and focal interictal epileptiform discharges are potential predictors of VNS efficacy. These findings provide important references for clinicians in selecting and evaluating patients for VNS treatment.

    Release date:2024-08-23 04:11 Export PDF Favorites Scan
  • Research progress of the role of periosteum in distraction osteogenesis

    Objective To review the research progress of the role of periosteum in distraction osteogenesis. Methods The related domestic and foreign literature about the role of periosteum in distraction osteogenesis in recent years was extensively reviewed, summarized, and the mechanism and influencing factors of periosteum during traction and osteogenesis were analyzed. Results The periosteum is rich in all kinds of cells (mesenchymal stem cells, osteoblasts, etc.), microvessel and various growth factors, which are necessary for the formation of new bone. It can promote the formation of new bone in the process of traction osteogenesis significantly. Conclusion The periosteum plays an important role in the progress of distraction osteogenesis.

    Release date:2017-07-13 11:11 Export PDF Favorites Scan
  • APPLIED ANATOMY OF SUPERFICIAL INFERIOR EPIGASTRIC ARTERY FLAP

    Objective To provide the anatomical basis for the appl ication of the superficial inferior epigastric artery flap. Methods Ten cadavers which were immersed in formal in less than 6 months and were perfused by red latex were used in this study. There were 8 males and 2 females with an average age of 58 years (range, 35-78 years). The origin, course, branch,distribution, diameter, pedicle length, and neighbour of superficial inferior epigastric artery and vein were observed in the 2 sides of inguinal region. Results In these series of 10 cadaver (20 sides) dissections, the superficial inferior epigastric artery was identified in 18 sides, which average cal iber was 1.48 mm with a mean vascular pedicle length of 4.80 cm. In 11 sides, the superficial inferior epigastric artery arose aspart of a common trunk with one or more other vessels; in other 7, it originated from the femoral. There were 4 branch modes of superficial inperior epigastric artery: single trunks (5 sides), double ramification (3 sides), single lateral ramification (7 sides), and single medial ramification (3 sides). The superficial inferior epigastric vein was observed in 20 sides, which average cal iber was 2.33 mm with a mean sides pedicle length of 5.45 cm. In 8 sides, the venous drainage was as an individual vein; in 12 sides, both patterns were observed (a pair of venae comitantes and an individual vein). Conclusion The inferior epigastric artery flap can be appl ied to microsurgical flap transfer, potentially in breast reconstruction, phalloplasty, reconstruction of head, neck and four l imbs defects.

    Release date:2016-09-01 09:04 Export PDF Favorites Scan
  • Application of folded transverse superficial epigastric artery perforator flap for large penetrating defect after buccal carcinoma resection

    Objective To explore the effectiveness of folded transverse superficial epigastric artery perforator flap in repairing the large penetrating defect after buccal carcinoma resection. Methods Between January 2019 and June 2021, 12 patients with buccal squamous cell carcinoma were treated. There were 6 males and 6 females with an average of 66.9 years (range, 53-79 years). The pathological stage was T3a-T4b, and the preoperative mouth opening was (3.08±0.46) cm. The disease duration ranged from 6 to 24 months, with an average of 15 months. After buccal carcinoma radical resection and neck lymph node dissection, the penetrating defects in size of 8 cm×6 cm to 16 cm×8 cm and in depth of 0.5-1.5 cm were remained. The transverse superficial epigastric artery perforator flap in size of 8 cm×6 cm to 14 cm×8 cm were harvested and folded to repair the penetrating defects. The donor site was sutured directly. Results All 12 skin flaps survived after operation, and the wounds healed by first intention. No internal or external fistula complications occurred. All incisions at the recipient site healed by first intention. All patients were followed up 12-18 months (mean, 14 months). There was no obvious abnormality in the color and texture of the flap, the oral and facial appearances were symmetrical, and there was no obvious swelling in the cheek. At last follow-up, the patient’s mouth opening was (2.89±0.33) cm, which was not significantly different from that before operation (t=1.879, P=0.087). The subjective satisfaction scores of 12 patients were 6-8 points, with an average of 7.3 points. Significant scars remained at the donor site but concealed in location. Conclusion The folded transverse superficial epigastric artery perforator flap can be used as a surgical method for repairing large penetrating defects after the buccal carcinoma resection, with a good recovery of facial appearance and oral function.

    Release date:2023-05-11 04:44 Export PDF Favorites Scan
  • Research advance in polyaryletherketones for biomedical applications

    With high thermal stability, excellent mechanical properties, suitable biocompatibility and radiolucency, polyaryletherketones (PAEKs) have been widely used in biomedical field such as trauma, spinal implants, craniomaxillofacial repair and so on. However, PAEKs are bio-inert in nature and often show weak osteointegration with host bone, limiting their further utilization in biomedical application. Therefore, how to improve the bioactivity and osteointegration of PAEK implants has become the focus in biomedical field. This paper reviews the current research advance and some existed problems in bioactive PAEKs, and outlooks the possible solution.

    Release date:2018-09-25 02:22 Export PDF Favorites Scan
  • Quantitative experiment and analysis of gradient-induced eddy currents on magnetic resonance imaging

    Pulsed magnetic field gradients generated by gradient coils are widely used in signal location in magnetic resonance imaging (MRI). However, gradient coils can also induce eddy currents in final magnetic field in the nearby conducting structures which lead to distortion and artifact in images, misguiding clinical diagnosis. We tried in our laboratory to measure the magnetic field of gradient-induced eddy current in 1.5 T superconducting magnetic resonance imaging device; and extracted key parameters including amplitude and time constant of exponential terms according to inductance-resistance series mathematical module. These parameters of both self-induced component and crossing component are useful to design digital filters to implement pulse pre-emphasize to reshape the waveform. A measure device that is a basement equipped with phantoms and receiving coils was designed and placed in the isocenter of the magnetic field. By applying testing sequence, contrast experiments were carried out in a superconducting magnet before and after eddy current compensation. Sets of one dimension signal were obtained as raw data to calculate gradient-induced eddy currents. Curve fitting by least squares method was also done to match inductance-resistance series module. The results also illustrated that pulse pre-emphasize measurement with digital filter was correct and effective in reducing eddy current effect. Pre-emphasize waveform was developed based on system function. The usefulness of pre-emphasize measurement in reducing eddy current was confirmed and the improvement was also presented. All these are valuable for reducing artifact in magnetic resonance imaging device.

    Release date:2017-04-13 10:03 Export PDF Favorites Scan
  • Analysis of risk factors for cervical central and lateral lymph node metastases in patients with papillary thyroid carcinoma

    ObjectiveTo investigate the risk factors affecting cervical central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) in patients with papillary thyroid carcinoma (PTC). MethodsThe patients with newly diagnosed with PTC who underwent surgical treatment in this hospital from April 2020 to December 2023 were included. The univariate and multivariate logistic regression analyses were conducted to identify the risk factors affecting the occurrences of CLNM and LLNM in patients with PTC and a prediction model was developed using these risk factors. Additionally, the discriminatory power of the predictive model for CLNM or LLNM was evaluated using the area under the receiver operating characteristic curve (AUC). ResultsA total of 297 patients with PTC were included in this study, among whom 149 (50.2%) cases developed CLNM, and 41 (13.8%) cases developed LLNM. The multivariate analysis indicated that the male, age <36 years old, and maximum tumor diameter >5 mm were the independent risk factors for CLNM in the patients with PTC (P<0.05). The independent risk factors for LLNM in the patients with PTC were the age ≥59 years old, bilateral or isthmus distribution of cancer foci, maximum tumor diameter >5 mm, and invasion of capsule (P<0.05). The AUC (95%CI) of the CLNM prediction model, constructed using three risk factors (gender, age, and maximum tumor diameter), was 0.693 (0.633, 0.752). For the LLNM prediction model, which incorporated four factors [age, distribution of cancer foci, maximum tumor diameter, and capsular invasion], the AUC (95%CI) was 0.776 (0.707, 0.846). ConclusionsThe findings of this study suggest that younger male patients with PTC (age <36 years), and a maximum tumor diameter >5 mm have a higher risk of CLNM. However, the predictive model constructed for CLNM demonstrates only moderate discriminatory power. In contrast, elderly patients (age ≥59 years old) with PTC exhibiting a maximum tumor diameter >5 mm, capsular invasion, and bilateral (or isthmus) lesions are at greater risk of LLNM. The predictive model developed for LLNM shows a certain discriminatory performance.

    Release date:2025-06-23 03:12 Export PDF Favorites Scan
  • Research and application of orthotopic DR chest radiograph quality control system based on artificial intelligence

    With the change of medical diagnosis and treatment mode, the quality of medical image directly affects the diagnosis and treatment of the disease for doctors. Therefore, realization of intelligent image quality control by computer will have a greater auxiliary effect on the radiographer’s filming work. In this paper, the research methods and applications of image segmentation model and image classification model in the field of deep learning and traditional image processing algorithm applied to medical image quality evaluation are described. The results demonstrate that deep learning algorithm is more accurate and efficient than the traditional image processing algorithm in the effective training of medical image big data, which explains the broad application prospect of deep learning in the medical field. This paper developed a set of intelligent quality control system for auxiliary filming, and successfully applied it to the Radiology Department of West China Hospital and other city and county hospitals, which effectively verified the feasibility and stability of the quality control system.

    Release date:2020-04-18 10:01 Export PDF Favorites Scan
  • Finite element analysis of the effect of knee movable unicompartmental prosthesis insertion shape and mounting position on stress distribution in the knee joint after replacement

    In unicompartmental replacement surgery, there are a wide variety of commercially available unicompartmental prostheses, and the consistency of the contact surface between the common liner and the femoral prosthesis could impact the stress distribution in the knee after replacement in different ways. Medial tibial plateau fracture and liner dislocation are two common forms of failure after unicompartmental replacement. One of the reasons is the mismatch in the mounting position of the unicompartmental prosthesis in the knee joint, which may lead to failure. Therefore, this paper focuses on the influence of the shape of the contact surface between the liner and the femoral prosthesis and the mounting position of the unicompartmental prosthesis on the stress distribution in the knee joint after replacement. Firstly, a finite element model of the normal human knee joint was established, and the validity of the model was verified by both stress and displacement. Secondly, two different shapes of padded knee prosthesis models (type A and type B) were developed to simulate and analyze the stress distribution in the knee joint under single-leg stance with five internal or external rotation mounting positions of the two pads. The results showed that under a 1 kN axial load, the peak contact pressure of the liner, the peak ACL equivalent force, and the peak contact pressure of the lateral meniscus were smaller for type A than for type B. The liner displacement, peak contact pressure of the liner, peak tibial equivalent force, and peak ACL equivalent force were the smallest for type A at 3° of internal rotation in all five internal or external rotation mounting positions. For unicompartmental replacement, it is recommended that the choice of type A or type B liner for prosthetic internal rotation up to 6° should be combined with other factors of the patient for comprehensive analysis. In conclusion, the results of this paper may reduce the risk of liner dislocation and medial tibial plateau fracture after unicompartmental replacement, providing a biomechanical reference for unicompartmental prosthesis design.

    Release date:2022-10-25 01:09 Export PDF Favorites Scan
  • Study on the effect of dynamic neuromuscular stabilization technique for chronic low back pain

    ObjectiveTo explore the effect of dynamic neuromuscular stabilization technique for chronic non-specific low back pain. MethodsFrom July 2019 to June 2020, 60 patients with chronic non-specific low back pain who underwent rehabilitation at the outpatient clinic of Sir Run Run Shaw Hospital Affiliated to Zhejiang University School of Medicine were prospectively selected. All patients were divided into trial group and control group by random number table method. There were 30 cases in each group. The control group used rehabilitation education and core muscle strength training. The trial group used dynamic neuromuscular stabilization of chest and abdomen combined with breathing control training on the basis of the treatment plan of the control group. The Visual Analogue Scale (VAS) score, Oswestry Dability Index (ODI), abdominal pressure stability, xiphoid level thoracic mobility and axillary level thoracic mobility were compared between the two groups of patients. ResultsAll the 60 patients in this study completed the trial, and there was no recurrent case during treatment, after treatment or during follow-up. There was no statistically significant difference in age, gender, height, weight, body mass index, or course of disease between the two groups (P>0.05). Taking VAS score as the dependent variable, the result of generalized estimating equations showed that the difference in VAS score between the trial group and the control group was statistically significant (χ2=4.132, P=0.042), and the VAS scores at 12 weeks of follow-up and at 8 weeks of treatment differed significantly from that before treatment (χ2=1618.814, P<0.001; χ2=1573.419, P<0.001); the between-group comparisons at different time points showed that the difference in VAS score between the two groups at 12 weeks of follow-up was statistically significant (P<0.001), and the remaining between-group differences were not statistically significant (P>0.05). Taking ODI score as the dependent variable, the result of generalized estimating equations showed that the difference in total ODI score between the two groups was statistically significant (χ2=11.063, P=0.001), and the ODI scores at 12 weeks of follow-up and at 8 weeks of treatment differed significantly from that before treatment (χ2=524.694, P<0.001; χ2=717.236, P<0.001); the between-group comparisons at different time points showed that there were statistically significant differences between the two groups at 8 weeks of treatment and at 12 weeks of follow-up (P<0.001). After treatment, the improvement of stability value of abdominal pressure [(−4.93±8.14) vs. (−1.33±4.78) mm Hg (1 mm Hg=0.133 kPa)], the improvement of xiphoid level thoracic mobility [(1.87±0.62) vs. (1.52±0.70) cm] and the improvement of axillary level thoracic mobility [(1.78±0.62) vs. (0.92±0.45) cm] in the trial group were better than those in the control group (P<0.05).ConclusionThe dynamic neuromuscular stabilization technique can improve the dysfunction and relieve the symptoms of patients with chronic non-specific low back pain, and it is worthy of promotion.

    Release date:2021-09-24 01:23 Export PDF Favorites Scan
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