Development and characterization of PLGA-Bupivacaine and PLGA-S75: R25 Bupivacaine (Novabupi®) biodegradable implants for postoperative pain

Abstract In the hospital environment, postoperative pain is a common occurrence that impairs patient recovery and rehabilitation and lengthens hospitalization time. Racemic bupivacaine hydrochloride (CBV) and Novabupi® (NBV) (S (-) 75% R (+) 25% bupivacaine hydrochloride) are two examples of local anesthetics used in pain management, the latter being an alternative with less deleterious effects. In the present study, biodegradable implants were developed using Poly(L-lactide-co-glycolide) through a hot molding technique, evaluating their physicochemical properties and their in vitro drug release. Different proportions of drugs and polymer were tested, and the proportion of 25%:75% was the most stable for molding the implants. Thermal and spectrometric analyses were performed, and they revealed no unwanted chemical interactions between drugs and polymer. They also confirmed that heating and freeze-drying used for manufacturing did not interfere with stability. The in vitro release results revealed drugs sustained release, reaching 64% for NBV-PLGA and 52% for CBV-PLGA up to 30 days. The drug release mechanism was confirmed by microscopy, which involved pores formation and polymeric erosion, visualized in the first 72 h of the in vitro release test. These findings suggest that the developed implants are interesting alternatives to control postoperative pain efficiently.

Research Progress of Biodegradable Vascular Stent / 中国医疗器械杂志

Biodegradable vascular stents have better biocompatibility than drug-eluting stents. The blood vessels are rebuilt and degraded after normal physiological functions are restored. Due to it will not stay in the body for a long time and the patients don't need taking anti-rejection drugs all the time, it becomes the focus of attention in the treatment of coronary heart disease. This article introduced the development history of biodegradable stents and reviewed the research status of several different materials of vascular stents (animals or humans)

Studies on efficacy of a bioabsorbable steroid-eluting sinus stent in the frontal sinus opening of chronic rhinosinusitis with nasal polyps / 中华耳鼻咽喉头颈外科杂志

Objective: To assess the efficacy of a bioabsorbable steroid-eluting sinus stent in improving surgical outcomes when placed in the frontal sinus ostium (FSO) following full endoscopic sinus surgery (ESS) in patients with whole group chronic rhinosinusitis with nasal polyps (CRSwNP). Methods: Patients with whole group CRSwNP who had similar lesions on bilateral sinus between September 2019 and March 2020 in Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Changhai Hospital were chosen. Patients with CRSwNP who underwent extended ESS were randomly assigned to receive a steroid-eluting sinus stent in one FSO whereas the contralateral side received surgery alone. Endoscopic evaluations recorded at 30, 90 days postoperative were graded by an independent assessment panel to assess the need for interventions in the FSO. Semi-quantitative data with CT and endoscopic score were performed by rank sum test. The need for postoperative intervention and the patency rate of FSO were analyzed using the McNemar test. Results: Thirty-one patients with whole group CRSwNP met all eligible criteria, including 17 males and 14 females, with the age of (44.5±11.8) years(x¯±s). Stents were successfully placed in one FSO of all patients. At 30 days post-ESS, the assessment panel reported that steroid-eluting stents reduced the need for postoperative interventions by 41.0% (χ2=5.314,P=0.021), the need for oral steroid interventions by 40.0% (χ2=4.133,P=0.042) and the need for surgical interventions by 74.8% (χ2=4.292,P=0.038) compared to control sinuses with no stents. Clinical surgeons also reported greater diameter of FSO compared to control sinuses at 30 days post-ESS (74.2% vs 48.4%, χ2=4.351, P=0.037). These results at 90 days post-ESS were consistent with those at 30 days post-ESS. Conclusion: Bioabsorbable steroid-eluting sinus stents in the FSO can reduce polyp formation, adhesion, and the need for postoperative interventions in FSO of CRSwNP patients and improve the early postoperative outcomes.

The safety and efficacy of Firesorb bioresorbable scaffold in first-in-man study for coronary artery disease: the four-year outcomes / 中华心血管病杂志

Objective: To evaluate the 4-year clinical outcomes of patients following Firesorb bioresorbable scaffold (BRS) implantation. Methods: The study reported the 4-year follow-up results of the FUTURE I study. FUTURE I was a prospective, single-center, open-label, first-in-man study which evaluated the feasibility, preliminary safety, and efficacy of Firesorb stent in the treatment of coronary artery stenosis. A total of 45 patients with single de novo lesions in native coronary arteries ,who hospitalized in Fuwai Hospital from January to March 2016 were enrolled. After successfully stent implantation these patients were randomized in a 2∶1 ratio into cohort 1 (n=30) or cohort 2 (n=15). The patients in cohort 1 underwent angiographic, IVUS or OCT examination at 6 months and 2 years; and cohort 2 underwent angiographic, IVUS or OCT at 1 and 3 years. All patients underwent clinical follow-up at 1, 6 months and 1 year and annually thereafter up to 5 years. The primary endpoint was target lesion failure (TLF, including cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization). Secondary endpoints included patient-oriented composite endpoint (PoCE, defined as composite of all death, all miocardial infarction, or any revascularization). Results: A total of 45 patients were enrolled and implanted with Firesorb BRS, including 35 males (77.8%), and the age was (54.4±9.3) years. At 4 years, 10 patients in cohort 1 were reexamined by coronary angiography and OCT examination. Among them, 2 patients' stents were completely degraded and absorbed. Compared with the OCT images of the other 8 patients in cohort 2 at 3 years, the degree of stent degradation was increased, and no stent adherence was found. The 4-year clinical follow-up rate was 100%. In 4-year clinical following up, 2 patients suffered PoCE (4.4%): 1 patient underwent non-target vessel revascularization the day after index procedure and target vessel revascularization (Non-target lesion revascularization) at 2-year imaging follow-up; the other patient underwent target lesion revascularization during imaging follow-up at 4 years but not due to ischemic driven. There was no scaffold thrombosis or TLF events through 4 years. Conclusions: Four years after the implantation, complete degradation and absorption of the Firsorb stent are evidenced in some patients. Firesorb stent is feasible and effective in the treatment of patients with non-complex coronary lesions.

Biocerámicos: aspectos farmaco-tecnológicos y clínicos de uso odontológico / Bioceramics: pharmatechnological and clinical aspects of dental use

Se analizan aspectos fármaco-tecnológicos y clínicos de biocerámicos bioabsorbibles compuestos por biovidrios con capacidad osteogénica y microbicida, para ser utilizados como relleno bioactivo en el conducto radicular y como tratamiento terapéutico en el sitio de a lesión apicoperirradicular de origen endodóntico. Mediante un diagrama ternario se consideraron las diversas variables cuyos valores determinan las diferentes fases de los vidrios bioactivos, hasta alcanzar la formación de hidroxiapatita, cuando se someten a un medio biológico. Se analizaron composición y mecanismo de acción en la reparación posendodóntica, que parte de la integración del biomaterial al tejido duro sano, sin formación de fibrosis o proceso inflamatorio inmune (AU)

Pharmacotechnological and clinical aspects of bioabsorbable bioceramics composed of bioglasses with osteogenic and microbicidal capacity are analyzed, to be used as a bioactive filler in the root canal and as a therapeutic treatment at the site of an apicoperiradicular lesion of endodontic origin. By means of a ternary diagram, the various variables whose values determine the different phases of the bioactive glasses were considered, until reaching the formation of hydroxyapatite, when subjected to a biological medium. Composition and mechanism of action were analyzed in post-endodontic repair, which starts from the integration of the biomaterial into healthy hard tissue, without the formation of fibrosis or an immune inflammatory process (AU)

Magnesium versus poly-L-lactic acid bioresorbable scaffolds: in vivo optical coherence tomography comparison of mechanical performance / Andamiajes bioresorbibles de magnesio versus poliméricos: comparación in vivo de su comportamiento mecánico por OCT

Abstract Background: Different mechanical properties have been suggested for metallic bioresorbable vascular scaffolds (BVS) in comparison to polymeric BVS. We aim to evaluate the acute mechanical performance of Magmaris® scaffold in comparison to Absorb®. Materials and Methods: Two groups of 10 coronary lesions treated with Magmaris® and Absorb® 1.1 (20584 vs. 21016 struts) were compared. In all cases, optical coherence tomographic (OCT) images were acquired after scaffold deployment. Baseline clinical, angiographic, and procedural characteristics were compared, including OCT evaluations. Results: No baseline clinical or angiographic significant differences were found between groups. The most common indication for revascularization was effort angina (60% vs. 70% p = 0.45) with no ST-elevation myocardial infarction (MI) cases. Main target artery was left anterior descending, with a mean vessel diameter of 3.46 ± 0.23 in Absorb® and 3.52 ± 0.19mm in Magmaris® groups (p = 0.56). All cases underwent pre- and post-dilatation with a procedural success rate of 100%. OCT analyses showed larger scaffold and vessel diameters in Magmaris® group: 3.11 ± 0.38 mm versus 3.07 ± 0.36 mm, p = 0.03 and 4.12 ± 0.51 mm versus 4.04 ± 0.46 mm, p = 0.04. Despite the application of slightly higher postdilatation pressures to Magmaris® devices (18.01 ± 2.15 vs. 17.20 ± 3.80 atm, p = 0.05), significantly lower percentages of disrupted and malapposed struts were identified within Magmaris® scaffolds (0.15% vs. 0.27%, p = 0.03 and 1.06% vs. 1.46% p = 0.01). No cardiac death, target vessel-related MI, or clinically driven target lesion revascularization was reported in a 30-day follow-up. Conclusion: Mechanical properties of Magmaris® scaffold allow achieving larger vessel and scaffold diameters in a safe manner, with lower rates of malapposition and scaffold disruption.

Resumen Introducción: Se ha sugerido la presencia de un distinto comportamiento mecánico entre los dos grupos principales de dispositivos bioresorbibles: metálicos y poliméricos. En este estudio evaluamos el comportamiento mecánico agudo del andamiaje bioresorbible metálico Magmaris® frente al del polimérico Absorb®. Métodos: Se compararon dos grupos de 10 lesiones coronarias tratadas con Magmaris® y Absorb® 1.1 (20584 vs. 21016 struts). En todos los casos se realizó estudio postimplante del dispositivo mediante tomografia de coherencia óptica (OCT). Se compararon las características basales clínicas y angiográficas, así como aspectos del procedimiento (incluídos los estudios de OCT) entre ambos grupos. Resultados: No se encontraron diferencias clínicas o angiográficas estadísticamente significativas entre ambos grupos. La indicación más frecuente de revascularización coronaria fué la presencia de angina de esfuerzo (60% vs. 70% p = 0.45), sin incluirse casos de IAMCEST. La arteria descendente anterior fué el principal vaso diana, con un diámetro medio de 3.46 ± 0.23 mm en el grupo de Absorb® y de 3.52 ± 0.19mm en el grupo de Magmaris® (p = 0.56). En todos los casos se realizó pre y postdilatación, con una tasa de éxito del procedimiento del 100%. Los estudios mediante OCT demostraron un mayor diámetro de stent y del vaso en el grupo de Magmaris®: 3.11 ± 0.38mm versus 3.07 ± 0.36 mm, p = 0.03 y 4.12 ± 0.51mm versus 4.04 ± 0.46mm, p = 0.04. A pesar de someter a los dispositivos Magmaris® a presiones de postdilatación ligeramente superiores (18.01 ± 2.15 vs. 17.20 ± 3.80 atm, p = 0.05), se identificó un menor porcentaje estadísticamente significativo de struts rotos o malapuestos en dicho grupo (0.15% vs. 0.27 %, p = 0.03 y 1.06 % vs. 1.46% p = 0.01). En un seguimiento a 30 días no se registraron eventos mayores: muerte cardíaca, IM relacionado con vaso diana o TLR. Conclusión: Las propiedades mecánicas del scaffold metálico bioresorbible Magmaris® permiten alcanzar mayores diámetros de stent y vaso de forma segura tras su implante, con una baja tasa de malaposición y disrupción.

Distinctive bone regeneration of calvarial defects using biphasic calcium phosphate supplemented ultraviolet-crosslinked collagen membrane

PURPOSE: To overcome several drawbacks of chemically-crosslinked collagen membranes, modification processes such as ultraviolet (UV) crosslinking and the addition of biphasic calcium phosphate (BCP) to collagen membranes have been introduced. This study evaluated the efficacy and biocompatibility of BCP-supplemented UV-crosslinked collagen membrane for guided bone regeneration (GBR) in a rabbit calvarial model.METHODS: Four circular bone defects (diameter, 8 mm) were created in the calvarium of 10 rabbits. Each defect was randomly allocated to one of the following groups: 1) the sham control group (spontaneous healing); 2) the M group (defect coverage with a BCP-supplemented UV-crosslinked collagen membrane and no graft material); 3) the BG (defects filled with BCP particles without membrane coverage); and 4) the BG+M group (defects filled with BCP particles and covered with a BCP-supplemented UV-crosslinked collagen membrane in a conventional GBR procedure). At 2 and 8 weeks, rabbits were sacrificed, and experimental defects were investigated histologically and by micro-computed tomography (micro-CT).RESULTS: In both micro-CT and histometric analyses, the BG and BG+M groups at both 2 and 8 weeks showed significantly higher new bone formation than the control group. On micro-CT, the new bone volume of the BG+M group (48.39±5.47 mm3) was larger than that of the BG group (38.71±2.24 mm3, P=0.032) at 8 weeks. Histologically, greater new bone area was observed in the BG+M group than in the BG or M groups. BCP-supplemented UV-crosslinked collagen membrane did not cause an abnormal cellular reaction and was stable until 8 weeks.CONCLUSIONS: Enhanced new bone formation in GBR can be achieved by simultaneously using bone graft material and a BCP-supplemented UV-crosslinked collagen membrane, which showed high biocompatibility and resistance to degradation, making it a biocompatible alternative to chemically-crosslinked collagen membranes.

Influence of Thickness and Width of Bioabsorbable Vascular Stent on Local Hemodynamics / 中国医疗器械杂志

The study reconstructed vascular model by the realistic Optical Coherence Tomography (OCT) data to investigate the influence of the local hemodynamics caused by different thickness and width of bioresorbable vascular scaffold (BRS) implantation in Left Anterior Descending (LAD) artery. The study explored the relationship between the stent structure and thrombus, and the result can provide a valuable reference for the optimal design of BRS.

Arthroscopic repair of Bankart lesion with bioabsorbable suture anchors / 中国骨伤

OBJECTIVE@#To evaluate early clinical effects of bioabsorbable suture anchors for the treatment of Bankart lesion.@*METHODS@#Total 23 patients with the Bankart lesion were treated with arthroscopic repair using bioabsorbable suture anchors from January 2010 to June 2017. There were 20 males and 3 females, with an average age of (23.4±3.9) years old (ranged, 19 to 34 years old). Fourteen patients had injuries on the right shoulder joint and 9 patients had the injuries on the left side. The mechanism of primary dislocation included 17 cases of training, 5 cases of sports injury and 1 case of falling down. The mean interval time from injury to surgery was(10.9±5.8) months (ranged, 3 to 36 months). The Bankart lesion was repaired by bio-cortical suture anchors. The Rowes rating system for Bankart repair was used to evaluate therapeutic effects.@*RESULTS@#All 23 patients were followed up, with a mean duration of(24.5±3.7) months(ranged, 18 to 39 months). At the latest follow up, there was no recurrent dislocation occurred, and all patients had returned to sports and work. The Rowes rating system for Bankart repair was 53.91±11.67 pre-operationally and 91.74±12.30 post operationally, respectively (@*CONCLUSION@#Applying bio-cortical bone suture anchors for the Bankart lesion is a reliable, efficient and cost effective treatment, which is also suitable for the revision of the Bankart lesion.

Design and mechanical properties of biodegradable polymeric stent / 生物医学工程学杂志

Biodegradable stents (BDSs) are the milestone in percutaneous coronary intervention(PCI). Biodegradable polymeric stents have received widespread attention due to their good biocompatibility, moderate degradation rate and degradation products without toxicity or side effects. However, due to the defects in mechanical properties of polymer materials, the clinical application of polymeric BDS has been affected. In this paper, the BDS geometric configuration design was analyzed to improve the radial strength, flexibility and reduce the shrinkage rate of biodegradable polymeric stents. And from the aspects of numerical simulation, in vitro experiment and animal experiment, the configuration design and mechanical properties of biodegradable polymeric stents were introduced in detail in order to provide further references for the development of biodegradable polymeric stents.

Long-term outcome (5-10 years) after non absorbable mesh insertion compared to partially absorbable mesh insertion for anterior vaginal wall prolapse repair

ABSTRACT Objective: To evaluate long-term (5-10 years) outcomes of Minimally Invasive Surgical (MIS) kit insertion with Prolift® (non-absorbable) mesh compared to the use of Prolift M® (partially absorbable), for anterior vaginal wall prolapse repair. Study design: In this retrospective study we compared women undergoing MIS kit Prolift® insertion (n=90) vs. Prolift M® insertion (n=79) for anterior vaginal wall prolapse repair between 2006 and 2012 at our Institution. A number of 169 women fulfilled the inclusion criteria and were included in the study. Results: During the study period 128 women (76%) completed full follow-up; of them 58 (73%) following MIS kit Prolift® insertion, and 70 (88%) following MIS kit ProliftM® insertion. There was no significant difference between the Prolift® and Prolift M® regarding parity (3.04 vs. 2.88, p=0.506), presence of hypertension (24.1% vs. 39.1%, p=0.088), diabetes mellitus (3.4% vs. 11.6%, p=0.109), or urinary stress incontinence (39.7% vs. 47.1%, p=0.475). All participants had been diagnosed with POP grade 3 or 4 before the procedure. No significant complications during the procedure or postoperative period were identified in the study groups. The follow-up period was at least five years in duration for both groups. Both groups were comparable according to questionnaires focused on function and satisfaction. Conclusion: Patients undergoing MIS kit Prolift® and Prolift M® insertion for anterior vaginal wall prolapse repair had comparable early and late postoperative outcomes. No differences in patient's function and satisfaction between the two groups were identified. According to our findings, there is no superiority to either of the two studied mesh devices.

Cicatrização: uso de matriz de colágeno / Healing: use of collagen matrix

Resumo A matriz de colágeno Ologen TM é um novo agente antifibrótico composto por uma matriz porosa de atelocolageno tipo I e glicosaminoglicanos reticulados, que pode ser utilizado como uma alternativa para a modulação da cicatrização nas cirurgias. Por ser altamente poroso e biodegradável, este implante auxilia nos processos de reparação fisiológicos que ocorrem no tecido conjuntivo e epitelial da lesão, sem a formação de tecido fibrótico, o qual acarreta insucesso cirúrgico e elevação da PIO. A Trabeculectomia (TREC) é considerada a cirurgia padrão para o tratamento do glaucoma, no entanto as taxas de sucesso cirúrgico a médio e longo prazo estão relacionadas a cicatrização do sítio operatório, envolvendo principalmente o tecido conjuntival e tenoniano. O processo de cicatrização é divido em 4 fases principais: coagulativa, inflamatória, proliferativa e remodeladora, com uma série de cascatas químicas e fatores bioquímicos liberados na tentativa de restabelecer a hemostasia. Diversas pesquisas na literatura já demonstraram os efeitos benéficos na cicatrização ao utilizar a matriz de colágeno Ologen em cirurgias oftalmológicas, além das possíveis complicações. Os resultados dos atuais estudos com implante de Ologen para o tratamento de glaucoma são encorajadores e promissores. No entanto, ensaios clínicos randomizados futuros com seguimento a longo prazo são necessários para avaliarmos a segurança e a eficácia do novo implante na modulação da cicatrização, alcançando melhores taxas de sucesso cirúrgico.

Abstract The Ologen™ collagen matrix is a new antifibrotic agent composed of a porous matrix of type I atelocolagene and cross-linked glycosaminoglycans, which can be used as an alternative for the modulation of healing in surgeries. Because it is highly porous and biodegradable, this implant assists in the physiological repair processes that occur in the connective and epithelial tissue of the lesion without the formation of fibrotic tissue, which leads to surgical failure and IOP elevation. The Trabeculectomy (TREC) is considered the standard surgery for the treatment of glaucoma; however, the surgical success rates in the medium and long term are related to surgical site healing, mainly involving conjunctival and tenonian tissue. The healing process is divided into 4 main phases: coagulative, inflammatory, proliferative and remodeling, with a series of chemical cascades and biochemical factors released in an attempt to restore hemostasis. Since several researches in the literature have already demonstrated the beneficial effects on healing by using the Ologen collagen matrix in ophthalmic surgeries, in addition to possible complications. The results of current Ologen implant studies for the treatment of glaucoma are encouraging and promising. However, future randomized clinical trials with long-term follow-up are necessary to evaluate the safety and efficacy of the new implant in modulating healing, achieving better rates of surgical success.

Stent biodegradable como tratamiento de la estenosis esofágica benigna refractaria / Biodegradable stent as treatment of refractory benign esophageal stricture (RBES)

Paciente mujer de 26 años de edad, natural y procedente de La Paz-Bolivia. Acudió con un tiempo de enfermedad de 15 meses caracterizado por disfagia progresiva. Un mes antes del comienzo de la sintomatología ingirió lejía con intenciones autolíticas. En el estudio de endoscopia digestiva alta diagnóstica se evidenció a los 25 centímetros de la arcada dentaria una estenosis, de unos 3 mm de diámetro, central y con el epitelio esofágico adyacente de aspecto conservado. En la radiografía de esófago contrastada se evidenció a nivel de tercio medio de esófago una estenosis tubular corta, de bordes lisos, de aproximadamente 2 cm de longitud. Se inició tratamiento mediante dilataciones mecánicas axiales con bujías Savary Guilliard con un intervalo entre sesiones de 2 a 3 semanas y con 8 sesiones en total. En la última sesión la bujía de mayor calibre usada fue 12,8 mm. Es entonces que tomando en consideración los criterios diagnósticos de Kochman, se hizo el diagnóstico de estenosis esofágica cáustica refractaria. Durante el periodo de realización de las dilataciones con bujías la paciente quedo embarazada, lo que dificultaba la realización de los procedimientos por el rutinario uso de control fluoroscópico. Con 14 semanas de gestación se implantó un Stent esofágico biodegradable no cubierto SX-ELLA de 10 cm de longitud. Presentamos el caso por ser un manejo alternativo y novedoso para este tipo de patología.

A 26-year-old female patient, from La Paz-Bolivia. She came with a disease period of 15 months characterized by progressive dysphagia. One month before the onset of the symptomatology she ingested bleach with autolytic intentions. In the study of diagnostic upper gastrointestinal endoscopy at 25 centimeters of the dental arch was evidenced a stenosis of about 3 mm in diameter, central and with adjacent esophageal epithelium of a preserved appearance. In the x-ray of contrasted esophagus at the level of the middle third of the esophagus was evidenced a stenosis, short tubular, with a smooth border, of approximately 2 cm in length. Treatment was initiated using axial mechanical dilatations with Savary Guilliard bougies with an interval between sessions of 2 to 3 weeks and with 8 sessions in total. In the last session the largest bougie used was 12.8 mm. It is then that taking into account the diagnostic criteria of Kochman, the diagnosis of refractory caustic esophageal stenosis was made. During the period of realization of the dilations with bougies the patient became pregnant, which made difficult the accomplishment of the procedures for the routine use of fluoroscopic control. At 14 weeks of pregnancy, a SX-ELLA uncovered biodegradable esophageal stent of 10 cm length was implanted. We present the case as an alternative and novel management for this type of pathology.

Barrier effect of improved porcine small intestinal submucosa absorbable membrane on early healing of mandibular defects in rabbits / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the barrier effect of an absorbable barrier membrane made by small intestinal submucosa (SIS) compared with Bio-Gide collagen membrane.@*METHODS@#12 healthy New Zealand male white rabbits were randomly assigned. A or B round bone defects with a depth of 2 mm and a diameter of 5 mm or 8 mm was made in each rabbit's mandibular. The following treatments were given respectively: covered with SIS membrane (S), covered with Bio-Gide membrane (G) and blank control (O). Then we got six groups: AS, AG, AO, BS, BG, and BO (n=4). After 4 weeks, the rabbits were sacrificed. The specimens were examined by naked-eye observation, new bone percentage (BV/TV) and bone mineralized density (BMD), which were measured and analyzed by Micro-CT. The data were analyzed with one-way ANOVA.@*RESULTS@#After 4 weeks, Bio-Gide membranes were fused with the surrounding tissue while SIS membranes held the form with no significant degradation. In the AS, BS and AG groups, the absorbable membranes smoothly covered on the new bone. While in the BG group, Bio-Gide membranes collapsed to the center of the bone defects. The 3D reconstruction of Micro-CT showed that a large number of newly formed trabeculae were found in the four groups of AS, BS, AG, and BG. In the central subsidence area of the BG group, the newly formed trabeculae were sparse. However only a small amount of new bone trabecula appeared at the bottom of the defects in groups AO and BO. Micro-CT quantitative results showed that BV/TV (39.10%±0.79%) and BMD [(517.73±11.22) mg/cm3] of AS group were significantly higher than those of AO group [26.67%±1.12%, (319.81±8.00) mg/cm3] (P<0.05), and there was no significant difference between AS group and AG group [38.15%±0.91%, (518.65±7.48) mg/cm3] (P>0.05). BV/TV (34.90%±1.35%) and BMD [(409.09±8.14) mg/cm3] of BS group were significantly higher than those of BO group [23.63%±2.07%, (171.00±16.24) mg/cm3] (P < 0.05). Meanwhile, there was no significant difference between BS and BG groups [33.40%±1.06%, (412.70±8.6) mg/cm3] (P>0.05). HE staining analysis revealed that significant bone formation was achieved in the AS, AG, BS and BG groups, and trabecular bone of AS and AG groups were thicker and denser. In AO and BO group, there were scattered new bone tissues in edges of host bone, and no coarse trabecular bone formed.@*CONCLUSION@#In the early healing of two sizes bone defects in rabbit mandibular, SIS membrane and Bio-Gide membrane have a similar barrier effect in guided bone regeneration. And SIS membrane's ability to maintain space for bone regeneration seems to be better.

The in vivo thrombosis evaluation for the biodegradable polymer stent / 生物医学工程学杂志

New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation on similar instruments and show the methodology on the preclinical evaluation.

In vitro experimental study on the mechanical properties of biodegradable polymer stents / 生物医学工程学杂志

experimental test for mechanical properties of a vascular stent is a main method to evaluate its effectiveness and safety, which is of great significance to the clinical applications. In this study, a comparative study of planar, V-groove and radial compression methods for the radial support property test were performed, and the effects of compression rate and circumferential position on the test results were conducted. Based on the three-point bending method, the influences of compression rate and circumferential position on flexibility were also explored. And then a best test proposal was selected to evaluate the radial support property and flexibility of the three self-designed stents and the comparative biodegradable vascular stent (BVS) (BVS1.1, Abbott Vascular, USA) with different outside diameters of 1.4 mm, 1.7 mm and 2.4 mm. The results show that the developing trends of the compression load with the compression displacement measured by the three radial support property test methods are the same, but normalized radial force values are quite different. The planar compression method is more suitable for comparing the radial support properties of stents with different diameters and structures. Compression rate has no obvious effect on the testing results of both the radial support property and flexibility. Compression circumferential position has a great impact on testing radial support property with the planar or V-groove compression methods and testing flexibility with three-point bending method. The radial support properties of all the three self-designed stents are improved at a certain degree compared to that of the BVS stent. The study has better guide significance and reference value for testing mechanical properties of vascular stents.

Clinical courses and degradation patterns of absorbable plates in facial bone fracture patients

BACKGROUND: Absorbable plates are widely used in open reduction and internal fixation surgeries for facial bone fractures. Absorbable plates are made of polyglycolic acid (PGA), polylactic acid (PLA), polydioxane (PDS), or various combinations of these polymers. The degradation patterns of absorbable plates made from different polymers and clinical courses of patients treated with such plates have not been fully identified. This study aimed to confirm the clinical courses of facial bone fracture patients using absorbable plates and compare the degradation patterns of the plates. METHODS: A retrospective chart review was conducted for 47 cases in 46 patients who underwent open reduction and internal fixation surgery using absorbable plates to repair facial bone fractures. All surgeries used either PLA/PGA composite-based or poly-L-lactic acid (PLLA)/hydroxyapatite (HA) composite-based absorbable plates and screws. Clinical courses were confirmed and comparisons were conducted based on direct observation. RESULTS: There were no naturally occurring foreign body reactions. Post-traumatic inflammatory responses occurred in eight patients (nine cases), in which six recovered naturally with conservative treatment. The absorbable plates were removed from two patients. PLA/PGA composite-based absorbable plates degraded into fragments with non-uniform, sharp surfaces whereas PLLA/HA composite-based absorbable plates degraded into a soft powder. CONCLUSION: PLA/PGA composite-based and PLLA/HA composite-based absorbable plates showed no naturally occurring foreign body reactions and showed different degradation patterns. The absorbable plate used for facial bone fracture surgery needs to be selected in consideration of its degradation patterns.

Clinical usefulness of fixation of absorbable implants with cyanoacrylate in comminuted fractures of the maxilla

BACKGROUND: The open reduction of craniofacial bone fractures requires internal fixation using metal plates and screws, which have been considered the gold standard. However, metal implants pose a risk of palpation, protrusion, and foreign body reaction, and they may require an additional operation for removal. Recently, good results have been reported for absorbable implants which complement the disadvantages of metal implants. This study presents the results of using absorbable mesh, plates, and screws with cyanoacrylate for more accurate and firmer fixation of comminuted fractures of the maxilla. METHODS: In total, 235 patients underwent operations for comminuted fractures of the maxilla. From January 2012 to December 2014, absorbable mesh and screws were used in 114 patients, while from January 2015 to December 2017, absorbable mesh, plates, and screws with cyanoacrylate were used in 121 patients. Open reduction of the bone fragments was performed, after which absorbable implants were accurately molded and fixed by screws. RESULTS: All patients underwent postoperative computed tomography scans, which showed highly accurate reduction and firm fixation in the patients who underwent procedures using absorbable implants, screws, and cyanoacrylate. There were no postoperative complications or cases of abnormal facial contour. CONCLUSION: When absorbable implants and screws are used for maxillary fractures, no additional surgery to remove the metal plate is required. In addition, the use of cyanoacrylate enables accurate and firm fixation of the tiny bone fragments that cannot be fixed with screws.