Biomechanical Analysis on NiTi Memory Alloy Stent for Lumbar Interbody Fusion / 医用生物力学

Objective To evaluate biomechanical properties of the nickel-titanium (NiTi) memory alloy stent and its in vitro biomechanical properties for lumbar interbody fusion. Methods The mechanical properties of the NiTi memory alloy stent were tested on mechanical testing machine. Moreover, lumbar interbody fusion was simulated on fresh lumbar specimens, and biomechanical properties of the NiTi memory alloy stent with matching bone graft for used for lumbar interbody fusion were analyzed and compared with the traditional box-shape cage. Results The maximum compressive strength of the NiTi memory alloy stent was ( 12 964 ± 962) N. The maximum deformation within the effective range of memory characteristics was (4. 68±0. 03) mm. The recovery rate of the NiTi memory alloy stent was up to 99. 86% . Compared with the intact lumbar model, the stability of the operative segment after the simulated lumbar interbody fusion using NiTi memory alloy stent alone was increased in the direction of anterior flexion, posterior extension, lateral flexion and rotation, which was equivalent to the box shape cage group (P>0. 05). After the combined use of autogenous bone granule and absorbable bone cement the ROM of the operative segment was further reduced (P0. 05). The pull-out strength of the NiTi memory alloy stent with matching bone graft group was significantly stronger than that of the box-shape cage group (P<0. 05). Conclusions The NiTi memory alloy stent in this study was designed with a matched bone granule-absorbable bone cement graft,which provided a new idea for the further optimization and development of lumbar interbody fusion. With excellent support and deformation properties, this NiTi memory alloy stent is biomechanical equivalent to the traditional box shape cage for lumbar interbody fusion, and can greatly improve the stability of surgical segment and the pull-out strength of implants after the combined use of autogenous bone granule and absorbable bone cement.

In Vitro Degradation Behavior of Absorbable Interface Screws / 中国医疗器械杂志

The composite material PLGA compounded with β-tricalcium phosphate (β-TCP) was prepared by melt blending method, and the absorbable interface screw was prepared by injection molding process. Prepare PBS buffer that simulates human body, conduct in vitro degradation experiments on interface screws according to relevant national and industry standards, then test and characterize interface screws at different time points for degradation of intrinsic viscosity, average molecular weight distribution, mass loss, mechanical properties and thermal properties. According to the degradation performance-time curve, determine the time node at which the interface screw loses the mechanical properties. In this paper, the in vitro degradation behavior of interfacial screws prepared from PLGA and β-TCP composites was studied in detail, providing a reference and basis for the degradation behavior of absorbable products prepared from PLGA and β-TCP composites.

Risk Analysis and Study of Post-marketing Adverse Events for Absorbable Sutures / 中国医疗器械杂志

Objective To investigate, analyze, and evaluate the risk data associated with the clinical use of absorbable sutures by retrieving and summarizing information from the databases of the US FDA and CNKI, as well as the adverse event reports related to absorbable sutures from January 2019 to October 2022 within Zhejiang province. The adverse event reports are obtained from both incident locations and monitoring organizations affiliated with the registrant. The aim is to identify the main risk factors associated with the clinical use of absorbable sutures. The key risk factors are potential product quality defects, product design and material selection, clinical selection and application, and postoperative recovery care including patient's self-care. Risk control strategies are further proposed to reduce or minimize the risk of adverse events caused by this product.

Metallic screw fixation versus absorbable screw fixation after open reduction in treatment of distal tibial epiphyseal fractures in adolescents / 中华创伤骨科杂志

Objective:To compare the efficacy between metallic screw fixation and absorbable screw fixation after open reduction in the treatment of adolescent distal tibial epiphyseal fractures.Methods:A retrospective study was conducted to analyze the data of 82 patients with closed distal tibial epiphyseal fracture who had been admitted to Department of Pediatric Orthopedics, Shengjing Hospital Affiliated to China Medical University from January 2013 to December 2020. There were 61 males and 21 females (aged from 8 to 15 years), and 39 left sides and 43 right sides. The Salter-Harris classification: type Ⅱ in 25 cases, type Ⅲ in 8 cases, and type Ⅳ in 49 cases. They were divided into 2 groups according to different internal fixation methods. Group A (42 cases) was subjected to open reduction and metallic screw fixation and group B (40 cases) to open reduction and absorbable screw fixation. Preoperative data, operation time, total treatment cost and complications during follow-up were recorded and compared between the 2 groups. In both groups at the last follow-up, anteroposterior and lateral ankle radiographs were taken for radiographic evaluation of the injury to the distal tibial epiphysis and the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was used to assess the ankle function.Results:The 2 groups were comparable because there were no significant differences in all their preoperative demographic data ( P>0.05). Group A was followed up for 18.0(16.0, 21.3) months while group B for 16.0(13.0, 20.0) months. The treatment cost for group A [27, 000 (25, 000, 33, 000) Yuan] was significantly higher than that for group B [23, 000 (19, 000, 27, 000) Yuan] ( P<0.05). The operation time was (112.4±34.3) min for group A and (101.0±41.1) min for group B, showing no significant difference ( P>0.05). The lateral distal tibial angle was 89.5 (88.0, 91.0)° on the affected side and 89.7°±1.8° on the unaffected sides in group A; it was 90.0 (88.3, 90.8)° on the affected side and 89.5°±1.8° on the unaffected side in group B. The anterior distal tibial angle was 81.9°±1.8° on the affected side and 81.8°±1.5° on the unaffected side in group A; it was 82.0 (81.0, 83.0)° on the affected side and 82.1°±2.2° on the unaffected side in group B. There was no significant difference in the above comparisons at the last follow-up in radiographic evaluation of the distal ankle joint between the affected and the unaffected sides in either group or between groups( P>0.05). There was a significant difference between the 2 groups in the rate of superficial skin infection [11.9% (5/42) versus 0% (0/40)] ( P<0.05), but there was no significant difference in the incidence of premature physeal closure between the 2 groups [11.9% (5/42) versus 5.0% (2/40)] ( P>0.05). The last follow-up revealed no significant difference in the AOFAS ankle-hindfoot score between group A [(90.6±4.9) points] and group B [(92.1±4.6) points] ( P>0.05). Conclusions:In the treatment of adolescent distal tibial epiphyseal fractures, compared with metallic screw fixation, absorbable screw fixation may lead to comparable efficacy in fixation, functional recovery and imaging evaluation, but no increased risk of premature physeal closure. Moreover, it spares the need for secondary surgical removal, and reduces operation time and treatment cost.

Absorbable punctal plug and its application in dry eye / 中华实验眼科杂志

The punctal plug is a small implant inserted into the tear ducts, which is currently the main clinical treatment for dry eye.The use of punctal plugs can maintain natural tears on the ocular surface and has a good effect on solving the long-term dry eye problem.The plug structure can mechanically block the lacrimal duct to maintain tears.The material of the puntal plug must have good biocompatibility to achieve the therapeutic effect without causing tubulitis or other complications.Therefore, the selection of a suitable punctal plug material has always been a hot spot in medical research.In general, punctal plug materials must be biocompatible, safe and comfortable.At present, common punctal plug materials are mainly divided into absorbable and non-absorbable.The absorbable punctal plugs are often biocompatible, safe and degradable compared to the non-absorbable ones.The use of absorbable punctal plug materials and their application in the dry eye were reviewed in this article.

A comparative study of absorbable screw fixation and absorbable screw combined with suture anchor fixation in treatment of avulsion fracture of posterior cruciate ligament at tibial insertion of knee joint / 中国修复重建外科杂志

OBJECTIVE@#To compare the effectiveness of open reduction of posterior cruciate ligament (PCL) avulsion fracture at tibial insertion of knee joint with absorbable screws fixation and absorbable screw combined with suture anchor fixation.@*METHODS@#The clinical data of 26 patients with PCL avulsion fracture at tibial insertion who met the selection criteria between March 2015 and October 2021 were retrospectively analyzed. Among them, 14 patients were fixed with simple absorbable screw (group A), and 12 patients were fixed with absorbable screw combined with suture anchors (group B). All patients were confirmed by X-ray film, CT, or MRI preoperatively, and got positive results in preoperative posterior drawer tests. There was no significant difference in gender, age, side of affected limb, time from injury to operation, comorbidities, and preoperative Meyers & McKeever classification, Lysholm score, and International Knee Documentation Committee (IKDC) score between the two groups ( P>0.05). The operation time and postoperative complications were recorded and compared between the two groups. At last follow-up, Lysholm score and IKDC score were used to evaluate the improvement of knee function.@*RESULTS@#There was no significant difference in operation time between the two groups ( P>0.05). All incisions healed by first intention, and no complication such as vascular and nerve injury or venous thrombosis occurred. All 26 patients were followed up 9-89 months, with an average of 55.3 months. The follow-up time of group A and group B was (55.7±23.2) and (56.8±29.3) months, respectively, with no significant difference ( t=-0.106, P=0.916). Radiographs showed bone healing in both groups at 3 months after operation, and no complication such as infection and traumatic arthritis occurred. At last follow-up, the posterior drawer test was negative in both groups, and the Lysholm score and IKDC score significantly improved when compared with the pre-operative values ( P<0.05). However, there was no significant difference in the improvement value between the two groups ( P>0.05).@*CONCLUSION@#For PCL avulsion fracture at tibial insertion of the knee joint, the open reduction and absorbable screw combined with suture anchor fixation can achieve reliable fracture reduction and fixation, which is conducive to the early rehabilitation and functional exercise, and the postoperative functional recovery of the knee joint is satisfactory.

Application of absorbable anchor combined with Kirschner wire in reconstruction of extension function of old mallet finger / 中国修复重建外科杂志

OBJECTIVE@#To investigate the feasibility and effectiveness of absorbable anchor combined with Kirschner wire fixation in the reconstruction of extension function of old mallet finger.@*METHODS@#Between January 2020 and January 2022, 23 cases of old mallet fingers were treated. There were 17 males and 6 females with an average age of 42 years (range, 18-70 years). The cause of injury included sports impact injury in 12 cases, sprain in 9 cases, and previous cut injury in 2 cases. The affected finger included index finger in 4 cases, middle finger in 5 cases, ring finger in 9 cases, and little finger in 5 cases. There were 18 patients of tendinous mallet fingers (Doyle type Ⅰ), 5 patients were only small bone fragments avulsion (Wehbe type ⅠA). The time from injury to operation was 45-120 days, with an average of 67 days. The patients were treated with Kirschner wire to fix the distal interphalangeal joint in a mild back extension position after joint release. The insertion of extensor tendon was reconstructed and fixed with absorbable anchors. After 6 weeks, the Kirschner wire was removed, and the patients started joint flexion and extension training.@*RESULTS@#The postoperative follow-up ranged from 4 to 24 months (mean, 9 months). The wounds healed by first intention without complications such as skin necrosis, wound infection, and nail deformity. The distal interphalangeal joint was not stiff, the joint space was good, and there was no complication such as pain and osteoarthritis. At last follow-up, according to Crawford function evaluation standard, 12 cases were excellent, 9 cases were good, 2 cases were fair, and the good and excellent rate was 91.3%.@*CONCLUSION@#Absorbable anchor combined with Kirschner wire fixation can be used to reconstruct the extension function of old mallet finger, which has the advantages of simple operation and less complications.

Study on the influence of buried thread nasal augmentation on dorsal soft tissue of nose and revision rhinoplasty / 中国修复重建外科杂志

OBJECTIVE@#To investigate the influence of buried thread nasal augmentation on dorsal soft tissue of nose and revision rhinoplasty.@*METHODS@#A clinical data of 29 patients requesting revision rhinoplasty after buried thread nasal augmentation, who were admitted between July 2017 and July 2019 and met the selection criteria, was retrospectively analyzed. All patients were female with an average age of 26.8 years (range, 18-43 years). The patiens were admitted to the hospital at 3-48 months after buried thread nasal augmentation (median, 15 months). Among them, there were 18 cases of insufficient nasal tip projection, 22 cases of insufficient nasal root projection, 7 cases of threads ectasia, 5 cases of threads exposure, 3 cases of infection, and 10 cases with two or more conditions. There were 9 cases of combined short nose deformity, 1 case of spherical hypertrophy of the nasal tip, 3 cases of deviation of the nasal columella, 3 cases of excessive width of the nasal base, and 1 case of nasal hump. Three infected patients only underwent threads removal and debridement. The rest patients underwent revision rhinoplasty, and the dorsum of the nose was made with polytetrafluoroethylene expansion; the tip of the nose was reshaped by taking autologous rib cartilage and alar cartilage in 16 cases, and by taking autologous septal cartilage and alar cartilage in another 10 cases. The threads and surrounding tissue specimens removed during operation were subjected to histologic observation. Nasal length and nasal tip projection were measured after revision rhinoplasty and the ratio was calculated to evaluate the nasal morphology; patient satisfaction was evaluated using the Likert 5-grade scale.@*RESULTS@#Patients were followed up 12-48 months (mean, 18 months). Inflammation was controlled in 3 patients with infections caused by buried thread nasal augmentation. The remaining 26 patients had satisfactory results immediately after revision rhinoplasty. Before revision rhinoplasty and at 7 days and 6 months after revision rhinoplasty, the nasal length was (4.11±0.34), (4.36±0.25), and (4.33±0.22) cm, respectively; the nasal tip projection was (2.34±0.25), (2.81±0.18), and (2.76±0.15) cm, respectively; and the nasal tip projection/nasal length ratio was 0.57±0.08, 0.65±0.05, and 0.64±0.04, respectively. There were significant differences in the nasal length and the nasal tip projection between time points ( P<0.05). There was a significant difference in the nasal tip projection/nasal length ratio between pre- and post-operation ( P<0.05), but there was no significant difference between 7 days and 6 months after operation ( P>0.05). The Likert score for satisfaction ranged from 1.5 to 5.0 (mean, 4.05). During follow-up period of 26 patients, no nasal prosthesis was exposed, and the shape of the nose was stable, and the nasal skin of 5 patients with exposed threads could be seen with different degrees of scarring; there was no infection, cartilage resorption, and no cartilage deformation, displacement, or exposure. Histological observation showed that absorbable threads were not only absorbed after implantation, but also with the prolongation of time, the inflammatory changes in the surrounding tissues caused by decomposition and absorption of the threads showed a gradual aggravation of the first, the heaviest inflammatory reaction in 6 to 12 months, and then gradually reduce the trend.@*CONCLUSION@#After implantation of the absorbable thread into the subcutaneous tissue of the nasal dorsum, the nature of the thread is different from the body's own tissue, which will affect the soft tissue compliance of the nasal dorsum. The degradation and absorption of the thread will stimulate the infiltration of inflammatory cells and the proliferation of fibroblasts in the surrounding tissue and then form scar tissue, which will affect the design and effect of revision rhinoplasty.

Sponges with colloidal silver nanoparticles help restore bone lost in endo-periodontal injuries

Introduction: Endo-periodontal lesions can lead to the formation of severe intraosseous defects in the periodontium; which can lead to tooth loss. Objective: Demonstrate that surgical periodontal therapy with the help of gelatin sponges, with colloidal silver nanoparticles, restores bone tissue lost in endo-periodontal lesions. Case presentation: 55-year-old male patient without systemic alterations, diagnosed with grade 3 endo-periodontal lesion in patients with periodontitis. It was treated first with ducts and then with periodontal surgery combined with gelatin sponges, which contain colloidal silver nanoparticles, and were placed filling the 2-wall bone defect involving > 80 percent of the root length, with 24 months of radiographic and clinical follow-up. Conclusions: Based on the case report, surgical periodontal therapy and filling of bone defects with gelatin sponges, which contain colloidal silver nanoparticles, were sufficient to restore the lost bone at a 24-month follow-up. However, further studies are needed to assess the clinical benefit of this material for the treatment of intraosseous defects(AU)

The efficacy of absorbable interface screw combined with bone tunnel on knee ligament fractures / 中国医师进修杂志

Objective:To investigate the efficacy of absorbable interface screw combined with bone tunnel on knee ligament fractures.Methods:One hundred and twenty patients with fractures of anterior cruciate ligament (ACL) admitted to Shanxian Haijiya Hospital from January 2018 to April 2020 were selected and according to the random number table method, they were divided into the absorbable group and the metal group, with 60 cases in each group. They adopted absorbable interface screw combined with bone tunnel and metal screw combined with bone tunnel respectively. The clinical efficacy, Lysholm knee function score, bone broadening degree and the incidence of postoperative complications of the two groups were compared.Results:The excellent and good rate in the absorbable group was higher than that in the metal group: 93.33%(56/60) vs. 80.00%(48/60), χ2 = 4.62, P<0.05. After operation for 3 and 6 months, the Lysholm knee fuction scores in the absorbable group were higher than those in the metal group: (78.42 ± 5.26) scores vs. (70.41 ± 4.28) scores, (92.57 ± 6.34) scores vs. (88.26 ± 6.30) scores, the differences were statistically significant ( P<0.05). After operation for 6 months, the broadening degree of the bone tunnels of femur anteroposterior projection, femur lateral position, leg anteroposterior projection, leg lateral position in the absorbable group were lower than those in the metal group: (2.34 ± 0.55) mm vs. (3.18 ± 0.71) mm, (2.31 ± 0.42) mm vs. (3.20 ± 0.61) mm, (2.80 ± 0.77) mm vs. (3.23 ± 0.72) mm, (2.82 ± 0.51) mm vs. (3.22 ± 0.62) mm, the differences were statistically significant ( P<0.05). The incidence of postoperative complications in the absorbable group was lower than that in the metal group: 5.00%(3/60) vs. 16.67%(10/60), χ2 = 4.23, P<0.05. Conclusions:Absorbable interface screw combined with bone tunnel for ACL fractures can effectively improve clinical efficacy, promote knee joint rehabilitation, reduce postoperative bone canal width, and reduce the incidence of postoperative complications.

Research progress of bioresorbable zinc alloy stent in the treatment of peripheral artery disease / 国际外科学杂志

With the development of percutaneous transluminal angioplasty, stent implantation has gradually become an important treatment for peripheral artery diseases, especially for arterial diseases of lower extremities. Due to the continuous exposure of the disadvantages of permanent metal stents and the continuous development of absorbable materials, researchers gradually pay attention to the bioresorbable stents with fewer long-term complications. At present, the application of bioresorbable stents in coronary artery disease has been relatively mature. This paper reviews the research progress of bioresorbable zinc alloy stents in peripheral artery disease.

Prevention of SSI in Cardiac Surgery by Using Intraoperative Measures for High-Risk Patients as Standard Precautions against Mediastinitis / 日本心臓血管外科学会雑誌

Background : Risk factors for surgical site infection (SSI) are thought to include poorly controlled diabetes mellitus, dialysis, and a long operating time, but patients without risk factors can also develop infection. Therefore, it is possible that SSI could be prevented by routinely using the precautions against SSI developed for high-risk patients. We investigated the route and pathogenetic mechanism of mediastinitis, which is the most frequent SSI after cardiac surgery. We hypothesized that mediastinitis occurred when the deep sternal marrow was contaminated by skin bacteria. Based on this hypothesis, we investigated the efficacy of various intraoperative prophylactic methods for preventing mediastinitis. Methods : We evaluated 658 patients undergoing cardiac surgery at our institution between April 2011 and July 2016. They were classified into two groups. Group C comprised 406 patients who received standard insertion of a sternal retractor after sternotomy. Group S was 252 patients in whom a retractor was inserted after covering the sternal marrow with oxidized cellulose hemostats and belt-like thin towels, with surplus parts of the towels being used to fill subcutaneous dead space at the superior and inferior margins of the midline wound. We investigated the following 10 risk factors for mediastinitis: diabetes (HbA1c≥7.5), renal failure (Cr≥2), smoking, obesity (BMI≥30), reoperation, urgent/emergency operation, intubation in the preoperative period, long operating time (≥8 h), reopening the chest for hemostasis, and coronary artery bypass grafting (CABG). Factors associated with mediastinitis were determined using univariate modeling analysis followed by multi-variate logistic regression analysis. Results : Mediastinitis occurred in 13 patients (2.0%). The significant risk factor for mediastinitis were urgent/emergency operation and CABG, but 1 patient had no risk factors. A univariate analysis showed statistical significance in CABG, presence of maneuver covering the sternal marrow, JapanSCORE-II in mortality and deep sternum infection (DSI). Reopening the chest for hemostasis, CABG, aortic aneurysm, plural risk factors, and JapanSCORE-II in DSI were identified as a risk factor by multiple logistic regression, not all factors showed a significant difference. Mediastinitis only occurred in group C, and it was significantly less frequent in group S with additional precautions against infection including propensity score matching analysis (p<0.05). Conclusion : When the bone marrow of the transected sternum was covered tightly to protect it from contamination by skin bacteria during cardiac surgery, the frequency of postoperative mediastinitis was significantly reduced.

Application of absorbable stent in interventional treatment of inferior knee artery disease / 中国综合临床

Objective:To explore the effect of the implantation of absorbable stents on the prognosis of patients with inferior knee artery balloon dilatation.Methods:From March 2018 to January 2021, twenty-five patients with drug absorbable stent implantation after inferior knee artery balloon dilatation (stent group) and 25 patients without absorbable stent implantation after inferior knee artery balloon dilatation (control group) were included in Qingdao Haici Medical Group Affiliated to Qingdao University. The improvement of symptoms, ankle brachial index, Rutherford classification and claudication distance before and after operation were compared. The symptoms, ankle brachial index, Rutherford grade, claudication distance and patency rate of the two groups were compared 6 months after operation. The preoperative and postoperative data were analyzed by independent sample t-test, and the patency rate was analyzed by χ 2 test. Results:The ankle brachial index in the stent group and the control group on the first day after operation was significantly higher than that before operation (0.18±0.11 vs. 0.85±0.15, t=18.5, P<0.05, 0.22±0.15 vs. 0.87±0.10, t=20.8, P<0.05), and the Rutherford classification decreased significantly (4.66±0.21 vs. 2.1±0.11, t=9.2, P<0.05, 4.58±0.33 vs. 2.3±0.22, t=12.9, P<0.05), the limp distance increased significantly ((27±8) m vs. (300±43) m, t=20.8, P<0.05, (42±14) m vs. (320±18) m, t=32.6, P<0.05). There was no significant difference in preoperative ankle brachial index, postoperative ankle brachial index, Rutherford grade and claudication distance between the two groups ( P>0.05). Six months after operation, the ankle brachial index (0.72±0.03 and 0.54±0.12; t=10.2, P<0.05), Rutherford classification ((1.72±0.17) and (3.23±0.22); t=12.8, P<0.05) and claudication distance ((580.00±137.00) m and (267.00±54.00) m; t=8.2, P<0.05) in the stent group and the control group were significantly better than those in the control group. The patency rate of stent group at 6 months was 68% (17/25), which was better than that of ordinary balloon dilatation group by 56% (14/25). Conclusion:Implantation of drug absorbable stents can significantly improve the prognosis of patients undergoing arterial balloon dilatation.

Evaluation of self-prepared absorbable hemostatic cellulose fibrils / 浙江大学学报·医学版

To evaluate the effectiveness and safety of self-prepared absorbable hemostatic fibrils.A kind of absorbable hemostatic fibrils were prepared by self-developed patent technique. The physical form and molecular structure of the fibrils and a marketed product Surgicel were characterized by general observation and infrared spectroscopy; the carboxyl content, pH value and relative molecular mass of fibrils were determined by potentiometric titration method, pH meter and copper ethylenediamine method, respectively. The behavior of the fibrils and Surgicel in contact with blood was observed by inverted microscope, the cytotoxicity was evaluated by agarose diffusion cell assay . The external iliac artery hemorrhage model and the back muscle infiltration model in rats were established. The hemostatic effectiveness of the fibrils was investigated by hemostasis time and blood weight, and the degradation and biosafety of fibrils were investigated by observation photography, immune organ weighing, hematology and coagulation index measuring, and histopathological examination. The fibrils and Surgicel had similar molecular structures. Compared with the raw material regenerated cellulose, the typical carboxyl stretching vibration absorption peak of -COOH appeared near in both fibrils and Surgicel. The carboxyl content of the two materials was about 20%, and the pH value was about 3. The relative molecular mass of the fibers after oxidation was 4466±79, which was close to that of Surgicel(>0.05). After contacting with blood, the volume of fibrils and Surgicel expanded, and absorbed blood of dozens of times as their own weight. The results of agar diffusion test showed that the fibrils had no cytotoxicity. The results of animal experiments showed that the hemostasis completed within and there was no significant difference in blood weight and speed of hemostasis between two products (both >0.05). The fibrils could be degraded 1 week after being implanted to the bleeding sites of the muscle. There were no pathological effects on the appearance, body weight, food intake, immunological tissue thymus, spleen, lymph nodes, hematology and coagulation indexes of the rats, and no obvious abnormality found in the histopathological examination. The prepared absorbable hemostatic fibrils have excellent biological safety and effectiveness.

Clinical observation of gelfoam in preventing cement leakage via the anterior vertebral wall in Kümmell's patients treated with percutaneous kyphoplasty / 中国骨伤

OBJECTIVE@#To evaluate the efficacy of gelfoam granules application in prevention of cement leakage via anterior vertebral wall in Kümmell's patients treated with percutaneous kyphoplasty (PKP).@*METHODS@#From June 2017 to December 2019, 13 patients with Kümmell disease were treated with PKP, and gelatin sponge was inserted into the anterior wall of vertebral body to prevent bone cement leakage. There were 3 males and 10 females, with an average age of (73.84±8.44) years. The visual analogue scale (VAS) was used to record the degree of pain before treatment and 1 day and 3 months after treatment; Oswestry Disability Index (ODI) was used to evaluate the thoracolumbar function before treatment and 3 monthsafter treatment;X-ray was used to observe the bone cement leakage after operation.@*RESULTS@#The VAS scores were 7.31±0.83, 2.92±1.13 and 1.69±1.11 before treatment and 1 day and 3 months after treatment, respectively. The VAS scores on the 1st day and 3 months after treatment were lower than those before treatment (@*CONCLUSION@#The application of gelfoam granules in PKP can effectively prevent the leakage of bone cement via the anterior vertebral wall of Kümmell patients, and reduce the risk of thermal and mechanical injury of soft tissues such as the aorta in front of the vertebral body, and does not affect the postoperative pain relief and the recovery of thoracolumbar function.

Biomechanical Simulation on Absorbable Magnesium Alloy Fixation System for Atlantoaxial Dislocation / 医用生物力学

Objective To investigate the feasibility of absorbable magnesium alloy screws in atlantoaxial dislocation fixation. Methods Four kinds of screws with triangular, rectangular, trapezoidal and zigzag thread were designed with WE43 magnesium alloy. The finite element simulation analyses were performed on the screw- polyurethane model and atlantoaxial fixation system model. The stress and displacement distributions on the models were obtained. Results The pull-out force simulations were carried out on four kinds of magnesium alloy screws according to ASTM F543 standard specification. The stresses of screws with triangular, rectangular, trapezoidal and zigzag thread were 146.20, 185.22,194.98, 264.55 MPa, respectively. The pull-out strength of the screw with triangular thread was the largest, and the peak stress was the smallest. The magnesium alloy screw with triangular thread used for atlantoaxial fixation could meet the strength requirements of flexion/extension, rotation and bending of the neck. The peak stress of the screw was reduced by 17.16 MPa after adding hydroxyapatite (HA) coating on the surface, and the stress on the screw was within the range of bonding strength between coating and magnesium alloy substrate. Conclusions Under the same loading condition, the screw with triangular thread has good stability and the best pull-out force performance. After heat treatment, the strength of magnesium alloy screw with triangular thread meets the load-bearing requirements for atlantoaxial dislocation fixation. HA coating on screw surface can optimize mechanical properties of the screw, and there exits good bonding strength between the coating and the screw.

Finite Element Analysis of Lumbar Interbody Fusion with Stent-Bone Granule-Absorbable Bone Cement / 医用生物力学

Objective To evaluate the biomechanical properties of lumbar interbody fusion with NiTi memory alloy stent-autogenous bone granule-absorbable bone cement. Methods The normal L3-5 segment finite element model (M0), L4-5 intervertebral fusion model with box fusion cage (M1), L4-5 intervertebral fusion model with NiTi memory alloy stent (M2) and L4-5 interbody fusion model with bone granule-absorbable bone cement for casting bone graft (M3) were constructed, respectively. The models were applied with mechanical loading to analyze the mechanical stability and the peak stress of L4 interior endplate. Results The range of motion (ROM) of L4-5 segment in M1 and M2 models was significantly lower than that of M0 model under flexion, extension, lateral flexion and axial rotation. In M3 model, the stability of the surgical segment was further improved and the peak stress of L4 interior endplate was much smaller than that of M1 and M2 models. Conclusions NiTi memory alloy stent and traditional box fusion cage have biomechanical equivalence when used alone in lumbar interbody fusion, and application of bone granule-absorbable bone cement for casting bone graft can further improve the stability and reduce the stress of endplate.

Absorbable versus Non-Absorbable Sutures in Paediatric Facial Trauma - A Cosmetic Assessment

Paediatric age group is most vulnerable to trauma. Children often suffer facial injuries. Though many topical skin adhesives and strips are available in the market which have given excellent cosmetic results, deeper injuries especially along the lines of high tension need suturing both with buried and skin sutures. Different variety of sutures are available in the market which are used as per the choice of the surgeon. Children are more apprehensive when it comes to suture removal. So use of absorbable sutures in place of non-absorbable sutures in skin can save the children from this fear factor. MethodsA prospective study was done in the department of plastic surgery from May 2012 to Dec. 2013 with an objective of studying the outcome of plain catgut suture as skin sutures versus non-absorbable skin suture Nylon in facial trauma in the paediatric age group. Chromic catgut was used as buried suture in both groups. All the patients presenting in emergency department with facial trauma with age 10 years or less were included in the study. Skin sutures, where needed removal, were removed on 5th post-operative day followed by follow up on 7th post-operative day, 3rd month and 8th month during which cosmetic assessment of scar was done. 25 patients who presented first in emergency and fulfilled the study criteria were sutured with 5 - 0 chromic catgut buried sutures and skin suture used was 6 - 0 Nylon and this group was labelled group A. Next 25 patients who presented in emergency for suturing were sutured with 5 - 0 chromic catgut as buried and plain catgut as skin suture. This group was labelled as Group B. Cosmetic outcome was assessed on 7th post-operative day, 3rd month and 8th month by using Beusang E cosmetic scar assessment scale based on two parameters which included colour and texture of scar.1 Statistical analysis was done with continuous variables expressed as Mean ± S.D. and categorical variables were expressed as count (percentage). Chi-square was used to compare the categorical variables between groups or Fisher exact test was used. ResultsOn 7th post-operative day follow up, out of 50 patients, 25 patients (50 %) in whom nylon was used as skin suture, 4 patients (16 %) had mismatch of colour. All scars were smooth in texture. In rest 25 patients (50 %) in whom plain catgut was used as a skin suture, 1 (4 %) patient had mismatch of the colour. None of the patients had frank pus in both groups & hypertrophic scar was seen in one patient. On 3rd month follow up, Group A patients with nylon as skin suture, 1 (4 %) patient showed hypertrophic scar whereas in Group B (8 %) patients had hypertrophic scar. On 8th month follow up, both group A & B had colour mismatch of 12% with firm texture of scar in 8% patients. ConclusionsThere is no long-term differences in cosmetic outcomes and complication rates between absorbable catgut suture and commonly used nylon sutures in the repair of facial trauma in paediatric age groups. So, absorbable sutures are acceptable alternative to non-absorbable suture especially in paediatric age group, keeping in mind their apprehensive nature and fear of suture removal.

Absorbable versus conventional methods for wound closures in surgeries for benign breast diseases: a randomized case control study

Background: Surgeons and patients prefer absorbable sutures for surgical wound closure in breast surgeries which are usually continuous subcuticular sutures so that patients can skip a hospital visit for suture removal. But in case of breast biopsies authors usually put circumareolar incisions. Here authors find it difficult to put continuous subcuticular sutures. In this contest authors thought of interrupted subcuticular sutures where authors can tackle the above-mentioned limitations; while actually reducing the financial burden of the patients.Methods: In this randomized case controlled study authors included elective general surgical procedures for benign breast diseases that was being carried out in the department of General Surgery Govt. Medical College, Kottayam for a period of 6 months starting from January 2017. Total number of cases taken are 20; 10 each in each group.Results: The mean rank for interrupted method was 14.20 and conventional method was 6.80. Mann-Whitney U statistic was 13.000 and p value was 0.03. Since p value was less than 0.05, authors had clear evidence to reject the null hypothesis. Therefore, authors concluded that both the methods were dissimilar and based on mean rank interrupted method seemed to be better method.Conclusions: Authors recommended interrupted absorbable subcuticular suturing technique in general surgical procedures for benign breast diseases, especially where authors used circumareolar incisions, which saved time of the surgeon and the patient. This can lead to considerable cost savings for the government without compromising clinical effectiveness or safety.