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find Author "ZHANG Kai" 25 results
  • 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
  • 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
  • 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
  • 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
  • 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
  • Treatment of tuberculosis in craniovertebral junction

    ObjectiveTo investigate the method of treating tuberculosis in the craniovertebral junction and its effectiveness.MethodsThe clinical data of 18 patients with tuberculosis in the craniovertebral junction between July 2010 and January 2019 was analyzed retrospectively. There were 14 males and 4 females, aged 21 months to 75 years (median, 35 years). The disease duration ranged from 2 weeks to 60 months (median, 4 months), and the affected segment was C0-C3. Preoperative visual analogue scale (VAS) score was 6.7±1.5 and the Japanese Orthopaedic Association (JOA) score was 16.1±1.8. The American Spinal Cord Injury Association (ASIA) grading system was applied to classify their neurological functions, according to which there were 6 cases of grade D and 12 cases of grade E. Among 18 patients, 4 patients underwent conservative treatment, 1 patient removed tuberculosis via transoral approach, 1 patient removed tuberculosis via posterior cervical approach, and 12 patients removed tuberculosis via transoral approach immediately after posterior cervical (atlantoaxial or occipitalcervical) fusion and internal fixation. The VAS score, ASIA grading, and JOA score were applied to evaluate effectiveness. X-ray film, CT, and MRI were taken after treatment to evaluate the tubercular recurrence, cervical stability, and bone healing.ResultsAll the patients were followed up 3 to 42 months (median, 12 months). At 3 months after treatment, the VAS score was 1.7±1.0, showing significant difference when compared with preoperative score (t=15.000, P=0.000); and the JOA score was 16.7±1.0, showing no significant difference when compared with preoperative score (t=1.317, P=0.205). According to ASIA grading, 6 patients with grade D before treatment had upgraded to grade E after treatment, while the remaining patients with grade E had no change in grading. The imaging examinations showed the good stability of the cervical spine. All patients had complete tuberculosis resection and no recurrence, and the patients who underwent internal fixation via posterior cervical approach achieved atlantoaxial or occipitalcervical bone fusion.ConclusionOn the premise of regular chemotherapy, if there is no huge abscess causing dysphagia or dyspnea, atlantoaxial instability, and neurological symptoms, patients can undergo conservative treatment. If not, however, the transoral approach can be used to completely remove the tuberculosis lesion in the craniovertebral junction. One-stage debridement via transoral approach combined with posterior cervical fusion and internal fixation can achieve satisfactory effectiveness.

    Release date:2021-01-07 04:59 Export PDF Favorites Scan
  • Simple pulmonary artery approach in subarterial ventricular septal defect repair in 102 patients: A clinical analysis

    ObjectiveTo summarize and analyze the experience of subarterial ventricular septal defect (VSD) repaired with simple pulmonary artery approach.MethodsWe retrospectively anlyzed the clinical data of 102 patients with subarterial VSD repaired with simple pulmonary artery approach in our hospital from August 2015 to October 2018. There were 67 males and 35 females at median age of 3 years (ranging 4 months to 49 years).ResultsThe median operation time was 82 (54-136) min. Median cardiopulmonary bypass time was 36 (21-62) min. The median aortic cross-clamping time was 13 (7-32) min. Thirty two patients of tracheal intubation were removed from the fast-track operating room immediately after surgery. Of the 102 patients, 67 patients underwent a small incision in the lower sternum. The median postoperative ICU stay time was 26 (13-36) h. There was no planned reoperations and no early death.ConclusionSimple pulmonary artery approach for subarterial ventricular septal defect repair with less intracardiac procedures, short operation time, less trauma, quick postoperative recovery has certain advantages in the application of specific groups.

    Release date:2020-01-17 05:18 Export PDF Favorites Scan
  • Safety and short-term clinical outcomes of magnetic resonance-guided laser interstitial thermal therapy for mesial temporal lobe epilepsy

    ObjectiveTo evaluate the clinical efficacy and safety of magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) for mesial temporal lobe epilepsy (MTLE), and to compare its outcomes with anterior temporal lobectomy (ATL). MethodsA retrospective cohort of 120 MTLE patients treated at Beijing Tiantan Hospital between August 2022 and August 2024 was analyzed, including 31 patients who underwent MRgLITT and 89 patients who underwent ATL. All patients received comprehensive presurgical evaluations, and stereoelectroencephalography (SEEG) was performed in selected cases. Clinical outcomes at 1 year were compared between the two groups, including seizure control (Engel classification, seizure reduction rate), cognitive and memory changes, quality of life, and postoperative complications. ResultsBaseline characteristics were comparable between groups. At 1-year follow-up, Engel class I outcomes were achieved in 71.0% of patients in the MRgLITT group and 67.4% in the ATL group. Seizure reduction rates were (89.6 ± 26.2)% for MRgLITT and (87.0 ± 28.7)% for ATL, with no significant difference (P=0.92). Postoperative changes in memory, cognition, and quality of life were not significantly different between groups (all P>0.05). The incidence of complications was low and similar between MRgLITT and ATL, including hemorrhage (3.2% vs. 2.2%), infection (16.1% vs. 19.1%), and neurological deficits (3.2% vs. 2.2%). ConclusionMRgLITT provides seizure control and safety outcomes comparable to ATL when applied to carefully selected MTLE patients, with the added advantages of minimal invasiveness and faster recovery. For patients with well-localized epileptogenic foci and hippocampal sclerosis, MRgLITT represents an important alternative to open resection.

    Release date:2025-09-05 01:18 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
  • 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
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