To investigate the influence of the preload and supporting stiffness on the hearing compensation performance of round window stimulation, a coupling finite model composed of a human ear, an actuator and a support was established. This model was constructed based on a complete set of micro-computed tomography (Micro-CT) images of a healthy adult’s right ear by reverse engineering technology. The validity of the model was verified by comparing the model’s calculated results with experimental data. Based on this model, we applied different amplitude preloads on the actuator, and changed the support’s stiffness. Then, the influences of the actuator’s preload and the support’s stiffness were analyzed by comparing the corresponding displacements of the basilar membrane. The results show that after applying a preload on the actuator, its hearing compensation performance was increased at the middle and high frequencies, but was deteriorated at low frequencies; besides, compared with using the fascia as the actuator’s support in clinical practice, utilizing the titanium alloy to fabricate the support would enhance the hearing compensation performance of the round window stimulation in the whole frequency range.
Along with the wide application of silicone gel implants in augmentation mammaplasty, more complications appeared. The author reported 24 cases of complicationssince 1989, including one case of heamtoma, one case of infection, two cases of injury of the sensory nerves to the nipple, four cases of asymmetric breast (as ymmetry in position and size), three cases of deformed appearance, six cases of constracture of the fibrous coating membrane, one case of rupture of prosthesis,one case of sinus formation and three cases of abnormal milk secretion. The causes of the complications and their prevention were discussed.
Objective To observe the clinical manifestations, therapeutic efficacy and results of bacterial culture of seven patients of scleral buckle (SB) infection after scleral bulking surgery. Methods Seven patients (seven eyes) underwent SB removal for SB infections were enrolled in this study. The patients included four males (four eyes) and three females (three eyes). The patients aged from 12 to 69 years, with a mean age of 42.7 years. There were four right eyes and three left eyes. The duration (interval between primary surgery and SB removal) ranged from two weeks to ten years, with a mean of 47.5 months. Six patients were concurrent with systemic disease. All the patients were examined for visual acuity, slit lamp microscope and indirect ophthalmoscope examination. Some patients also received external eye examination and fundus photography. Whether SB exposure or not and the clinical manifestations were observed. SB removal was performed in all the patients and the SB were sent to the laboratory for bacterial culture. The follow-up time ranged from two weeks to eight months, with a mean of 3.2 months. Whether infections recurrence and retinal detachment or not were observed. Results SB exposure was in three eyes. Obvious ocular pain and swelling, conjunctival hyperemia and visible yellow-white discharge in the conjunctival sac were presented in two eyes; irritation and discharge were in one eye. No SB exposure was in four eyes. Ocular pain and swelling, conjunctival hyperemia and visible yellow-white discharge in the conjunctival sac were presented in two eyes. Repeated subconjunctival hemorrhage and diplopia were presented in one eye. Visual acuity decline, conjunctival sac discharge and total retinal detachment were in one eye. All patients had no intraocular inflammation. The infection was controlled after SB removal and the retina was attached during the follow-up. The bacterial culture were all positive, which included Staphylococcus aureus, Staphylcoccus epidermidis and Erysipelothrix rhusiopathiae, Gram positive corynebacterium, Aspergillus flavus, Kocuria roseus, Streptococcus oralis, Maxwell Corynebacterium. Conclusions The clinical manifestations of SB infection and the pathogenic microorganisms are variable. SB removal can control the infection.
Meniscus injury has been one of the most common knee injuries in current society. The research on artificial meniscus implants as substitutes in meniscus reconstruction therapy has become global focus in order to solve clinical problems such as irreparable meniscus injury and symptoms after full or partial meniscectomy. At present, researches on artificial meniscus implants mainly focus on biodegradable meniscus scaffolds and non-biodegradable meniscus substitutes. Although the commercialized meniscal implants, such as CMI®, Actifit® and NUsurface®, have been applied in the clinical, none of them can perfectively restore or permanently replace the natural meniscus tissue, effectively solve the symptoms after meniscectomy, and prevent cartilage degenerative diseases. The research progress, application, advantages and disadvantages of different kinds of artificial meniscus implants are reviewed in this manuscript, and the prospect is provided.
ObjectiveTo investigate the effectiveness of digital three-dimensional (3D) printing osteotomy guide plate assisted total knee arthroplasty (TKA) in treatment of knee osteoarthritis (KOA) patients with femoral internal implants. Methods The clinical data of 55 KOA patients who met the selection criteria between July 2021 and October 2023 were retrospectively analyzed. Among them, 26 cases combined with femoral implants were treated with digital 3D printing osteotomy guide plate assisted TKA (guide plate group), and 29 cases were treated with conventional TKA (control group). There was no significant difference in gender, age, body mass index, side, Kellgren-Lawrence classification, preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) knee score, knee range of motion, and other baseline data between the two groups (P>0.05). The operation time, intraoperative blood loss, incision length, postoperative first ambulation time, surgical complications; VAS score, knee HSS score, knee range of motion before operation, at 1 week and 3 months after operation, and at last follow-up; distal femoral lateral angle, proximal tibial medial angle, hip-knee-ankle angle and other imaging indicators at last follow-up were recorded and compared between the two groups. ResultsThe operation time, incision length, intraoperative blood loss, and postoperative first ambulation time in the guide plate group were significantly lower than those in the control group (P<0.05). In the control group, there were 1 case of incision rupture and bleeding and 1 case of lower limb intermuscular venous thrombosis, which was cured after symptomatic treatment. There was no complication such as neurovascular injury, incision infection, or knee prosthesis loosening in both groups. Patients in both groups were followed up 12-26 months, with an average of 16.25 months. The VAS score, HSS score, and knee range of motion improved at each time point after operation in both groups, and further improved with time after operation, the differences were significant (P<0.05). The above indicators in the guide plate group were significantly better than those in the control group at 1 week and 3 months after operation (P<0.05), and there was no significant difference between the two groups at last follow-up (P>0.05). At last follow-up, the distal femoral lateral angle, the proximal tibial medial angle, and the hip-knee-ankle angle in the guide plate group were significantly better than those in the control group (P<0.05). Conclusion The application of digital 3D printing osteotomy guide plate assisted TKA in the treatment of KOA patients with femoral implants can simplify the surgical procedures, overcome limitations of conventional osteotomy guides, reduce surgical trauma, achieve individualized and precise osteotomy, and effectively restore lower limb alignment and knee joint function.
In recent years, bone implant materials such as titanium and titanium alloys have been widely used in the biomedical field due to their excellent mechanical properties and good biocompatibility. However, in clinical practice, bacterial adhesion to the material surface and postoperative infection issues may lead to implantation failure. Based on the antibacterial mechanism, this review elaborated on the antibacterial surface design of titanium implants from the aspects of anti-bacterial adhesion, contact sterilization and photocontrol sterilization. Surface modification of titanium or titanium-based alloy implants with different techniques can inhibit bacteria and promote osseointegration. Thus, the application range of multifunctional titanium-based implants in the field of orthopedics will be expanded.
Znic (Zn) alloys with good cytocompatibility and suitable degradation rate have been a kind of biodegradable metal with great potential for clinical applications. This paper summarizes the biological role of degradable Zn alloy as bone implant materials, discusses the mechanical properties of different Zn alloys and their advantages and disadvantages as bone implant materials, and analyzes the influence of different processing strategies (such as alloying and additive manufacturing) on the mechanical properties of Zn alloys. This paper provides systematic design approaches for biodegradable Zn alloys as bone implant materials in terms of the material selection, product processing, structural topology optimization, and assesses their application prospects with a view to better serve the clinic.
Objective To observe the inhibitory characteristics of silver nanoparticles (AgNP) on bacterial biofilms and investigate their inhibitory effect on biofilm formation on three common orthopedic biomaterials. Methods The minimal inhibitory concentration (MIC) and minimal biofilm inhibitory concentration (MBIC) of AgNP were determined by microplate dilution assay. Biofilms of Staphylococcus aureus (ATCC 25923) were cultured on three orthopedic biomaterials (titanium alloy, titanium oxide, and stainless steel) and intervened with AgNP at concentrations of 32, 16, 8, 4, 2 and 0 μg/mL to determine the MBICs on the three materials. The effects of AgNP on biofilm formation were analyzed by scanning electron microscopy and measuring optical density. Results The MIC and MBIC of AgNP in the microplate assay were both 16 µg/mL. The MBICs of AgNP on biofilm formation in titanium oxide, titanium alloy, and stainless steel were 16 μg/mL, 32 μg/mL, and 32 μg/mL, respectively. Among the three materials, the lowest optical density was observed on titanium oxide, while the highest was on titanium alloy. Conclusions AgNP has strong antibacterial biofilm characteristics and can prevent the formation of Staphylococcus aureus biofilm in vitro. Biofilm formation is most pronounced on titanium alloy, least on titanium oxide, and intermediate on stainless steel.
Objective To evaluate the efficacy and safety of intraoperative mesenchymal chemotherapy with 5-FU implants in radical gastrectomy of advanced gastric cancer. Methods From January 2008 to September 2009， 102 patients with historically proven advanced gastric cancer were enrolled in our department and were allocated to undergo either radical gastrectomy and intraoperative mesenchymal chemotherapy with 5-FU implants 800 mg（treatment group， n=51）， or radical gastrectomy alone （control group， n=51）. The postoperative complications and recurrence rate between two groups were compared. Results There were no significant differences on the volume of abdominal cavity drainage， count of white blood cells， albumin level， and gastrointestinal adverse events between the two groups （P＞0.05）. After a median follow-up of 28 months， the local recurrence rate was lower among patients in treatment group than that in control group （16.3% vs. 39.1%， P＜0.05）， the survival rate of 3-year was higher in treatment group than that in control group （85.8% vs. 67.3%， P＜0.05）. Conclusions Compared with the control group， there are no significant adverse reactions on patients with advanced gastric cancer who were implanted fluorouraci1 implants during operation， which can reduce local recurrence rates and improve the survival rates.
ObjectiveTo summarize the related research progress of antibacterial modification of orthopaedic implants surface in recent years. Methods The domestic and foreign related literature in recent years was extensively consulted, the research progress on antibacterial modification of orthopaedic implants surface was discussed from two aspects of characteristics of infection in orthopedic implants and surface anti-infection modification. Results The orthopaedic implants infections are mainly related to aspects of bacterial adhesion, decreased host immunity, and surface biofilm formation. At present, the main antimicrobial coating methods of orthopaedic implants are antibacterial adhesion coating, antibiotic coating, inorganic antimicrobial coating, composite antimicrobial coating, nitric oxide coating, immunomodulation, three-dimensional printing, polymer antimicrobial coating, and “smart” coating. Conclusion The above-mentioned antibacterial coating methods of orthopedic implants can not only inhibit bacterial adhesion, but also solve the problems of low immunity and biofilm formation. However, its mechanism of action and modification are still controversial and require further research.