Polydioxanone Research Articles

Smart PDOs™ and the Cartesian Technique™: A milestone in facial rejuvenation with bioactive scaffolds

Objectives: Evaluate the controlled release of silicon from smart polydioxanone suture (Smart PDOs™) and the clinical effect of the Cartesian Technique™ in face lifting. Material and Methods: This study was preclinical and clinical trials randomized, uncontrolled, and phase I carried out. Preclinical trials included instrumental analysis of silicon-enriched sutures by light microscopy, electron microscopy, and Ultraviolet-visible (UV-vis) spectroscopy. The clinical trial included 35 patients with primary and secondary rhytides, grade I lipomatosis, and grade I deflation. Polydioxanone (PDO) sutures are inserted following the Cartesian Technique™, a vectorial lift from the intersection of the Cartesian planes of the face. Once the cannulas were inserted with the PDO thread, 0.1 mL of organic silicon was dosed. Turgidity was examined by the pinch test of skin turgor. To measure the position of flaccid or deflated tissues, the scale used was the deflation scale. Results: The controlled release of organic silicon from the PDO sutures was verified. Its clinical application revealed that after 8 days the improvement in turgidity, wrinkle reversal, and flaccidity tightening was maintained in 100% of the sample. At 15 days, reversal of rhytides was observed, softening of deep furrows in 80%, and the initial turgor and skin tightening maintained without deflation in 90% of cases. Histopathological findings reveal that silicon synergistically potentiates the tissue effect of the PDO suture, generating greater biostimulation of fibroblasts with better quality collagen fibers, greater restructuring and redensification of the skin, and avoiding the late inflammatory response. Conclusion: The Cartesian Technique™ with Smart PDOs™ is an effective protocol for skin replenishment that enhances cell biostimulation through the release of bioactive drugs.

Animal Experimental Study of Bioabsorbable Left Atrial Appendage Occluder.

Left atrial appendage (LAA) closure can prevent stroke in high-risk patients with atrial fibrillation.A bioabsorbable LAA occluder made of degradable polymer materials, such as polydioxanone (PDO) and poly-L-lactic acid (PLA), and nitinol wire was used. Occluders were successfully implanted in 18 Chinese rural dogs, 2 of which died within 48 hours after operation due to pericardial tamponade and hemorrhage, respectively. Follow-up observation was performed after transcatheter LAA closure. New tissue was found on the surface of the occluder 2 months after operation. No adjacent structures such as the mitral valve and the left superior pulmonary vein were affected by the occluder discs. Hematoxylin and eosin (HE) staining was performed at 3 months after operation, which showed intact intimal structure on the occluder surface, and unabsorbed PDO and PLA were observed. Scanning electron microscopy showed irregular arrangement of endothelial cells. New endothelial tissue was observed to completely cover the occluder at 6 months after operation. Most PDOs were replaced by fibrous connective tissue, and scanning electron microscopy showed regularly arranged endothelial cells. Pathological examination at 12 months showed only a small remnant of PDO. The gross specimens of the liver, spleen, and kidneys and pathological examination did not indicate thromboembolism.The bioabsorbable LAA occluder made of PDO, PLA, and nitinol wire was safe and effective for the occlusion of LAA in dogs. The surface of the occluder was endothelialized half a year after operation. The absorbable materials of the occluder were degraded after 1 year.

Tensile testing in feline ventral abdominal coeliotomy closure with different sizes of polydioxanone suture material: a biomechanical study.

The aim of this study was to evaluate, in vitro, the load and type of failure of the sutured ventral abdominal fascia of cats with different sizes of suture material made of polydioxanone (PDX) (2-0, 3-0, 4-0, 5-0 USP). A total of 32 samples of the ventral abdominal wall from 16 cadaveric cats were harvested using an hourglass-shaped template. The samples were sectioned longitudinally along the linea alba and then sutured together in a continuous pattern using four different randomly assigned sizes of pdx suture material (2-0, 3-0, 4-0, 5-0 USP). A universal testing machine was used for linear distraction of the samples. The tensile strength and type of failure were recorded and analysed. Three types of failure were defined: suture material failure (S), suture line failure (T1) and failure of the abdominal wall further away from the linea alba (T2). The frequency of suture material failure decreased with increasing suture size. Suture size 5-0 failed due to a S failure in 6/8 samples, PDX 4-0 failed in 2/8 samples and PDX 3-0 failed in only 1/8 samples. However, PDX 2-0 failed due to only T1 or T2 failures, with both failures being almost equally represented. No statistically significant differences in the load to failure between PDX 2-0, 3-0 and 4-0 were noted (P >0.05). The risk of suture failure increased with decreasing suture size diameter. PDX 2-0 and 3-0 can be used without reservation for the closure of ventral midline coeliotomy in cats. Although there was no statistically significant difference between PDX 2-0, 3-0 and 4-0, PDX 4-0 showed a higher probability for suture breakage and should be used only after careful consideration of the patient while clinical evaluation is pending. Pdx 5-0 cannot be recommended as a safe suture size for this type of surgical closure.

Volumizing and Cogged Threads for Nose Augmentation.

Nose augmentation using nonsurgical methods, including volumizing and cogged threads, has gained popularity due to its minimally invasive nature, shorter recovery times, and reduced risks compared to traditional rhinoplasty. However, there is limited literature on the use of these techniques in the Asian population. This study aims to present two successful cases of nose augmentation using volumizing and cogged threads, providing evidence of their effectiveness and demonstrating the insertion techniques through a supplementary video. Two female patients (aged 26 and 33) underwent nonsurgical nose augmentation. The first patient received volumizing threads to enhance nasal contour, while the second patient received cogged threads to refine the nasal tip and alar base. Both procedures were performed using polydioxanone (PDO) threads, with follow-ups conducted to assess the outcomes. Both patients exhibited significant improvement in nasal contour and projection, with outcomes maintained for up to 8 months post-procedure. The patients reported high satisfaction with the aesthetic results, and no complications were observed during the follow-up period. Volumizing and cogged threads offer a promising nonsurgical alternative for nose augmentation, particularly in patients seeking minimal invasiveness and natural-looking results. While the initial outcomes are positive, further research is needed to evaluate the long-term safety and effectiveness of these techniques, especially in the Asian demographic.

In Vitro Corrosion of Polyester-Coated Magnesium Alloy under pH-Static Conditions.

The resorption rate of bioresorbable implants requires tuning to match the desired field of application. The use of Mg as implant material is highly advantageous, as it provides sufficient mechanical strength combined with its biodegradability. Consequently, the implant vanishes after it has served its intended purpose, allowing the complete restoration of natural tissue and organ function. However, a biodegradable Mg implant requires a biodegradable coating to slow the rate of Mg corrosion, as a permanent coating would negate the benefits of using Mg as an implant material. Therefore, degradable polymers are the materials of choice, especially polyester-based coatings, such as PLLA, as they have been proven in clinical practice over the long term. Within this work, the degradation retarding effect of a physical barrier in form of four clinically relevant polyester-based coatings, poly-l-lactide (PLLA), poly-l-lactide-co-glycolide (PLGA), poly(l-lactide-co-PEG) triblock copolymer (PLLA-co-PEG), and polydioxanone (PDO), is investigated in vitro under pH-static conditions using CO2 gas to compensate pH changes due to Mg corrosion. Coating thicknesses of 7.5 to 8.3 μm were comparable to commercially available stent systems. Quantitative analysis of magnesium concentration in buffered test medium by a photometric assay allows real-time monitoring. Shielding effect of different polyesters through polymer coating and formation of a protective passivation layer beneath the polymer coating was observed and characterized using SEM and EDX techniques. Our finding was that even imperfect polymer layers provide a considerable protective effect, and the used in vitro setup matches reported in vivo observations regarding elemental composition of corrosion products.

Study on in vivo and in vitro degradation of polydioxanone weaving tracheal stents

The appropriate degradation characteristics of polydioxanone (PDO) are necessary for the safety and effectiveness of stents. This study aimed to investigate the degradation of PDO weaving tracheal stents (PW stents)in vitroandin vivo. The degradation solution ofS. aureus(SAU),E. coli(ECO),P. aeruginosa(PAE), and control (N) were prepared, and the PW stents were immersed for 12 weeks. Then, the radial support force, weight retention, pH, molecular structure, thermal performance, and morphology were determined. Furthermore, the PW stents were implanted into the abdominal cavity of rabbits, and omentum was embedded. At feeding for 16 weeks, the mechanical properties, and morphology were measured. During the first 8 weeks, the radial support force in all groups was progressively decreased. At week 2, the decline rate of radial support force in the experimental groups was significantly faster compared to the N group, and the difference was narrowed thereafter. The infrared spectrum showed that during the whole degradation process, SAU, ECO and PAE solution did not lead to the formation of new functional groups in PW stents.In vitroscanning electron microscope observation showed that SAU and ECO were more likely to gather and multiply at the weaving points of the PW stents, forming colonies.In vivoexperiments showed that the degradation in the concavity of weaving points of PW stents was more rapid and severe. The radial support loss rate reached more than 70% at week 4, and the radial support force was no longer measurable after week 8. In omentum, multinuclear giant cells and foreign giant cells were found to infiltrate. PW stents have good biocompatibility. The degradation rate of PW stents in the aseptic conditionsin vivowas faster than in the bacteriological environmentin vitro.

Assessment of the Mechanical Properties of Different Suture Materials for Oral Surgery: An In Vitro Tensile Strength Study.

Sutures are essential components of wound closure in oral surgery, and the mechanical properties of suture materials play a crucial role in determining surgical outcomes. Understanding the tensile strengths of various suture materials is vital for selecting the most appropriate material for specific clinical applications. This study aimed to assess the tensile strength of suture materials commonly used in oral surgery through an in vitro tensile strength study. A total of 192 samples of six commonly used suture materials (polyglycolic acid (PGA), polyglactin 910 (PGLA), polylactic acid (PLA), polydioxanone (PDO), silk, and nylon) were subjected to tensile strength testing using a universal testing machine. Descriptive statistics were used to summarize the tensile strength of each suture material. A comparative analysis was conducted using appropriate statistical tests to identify any significant differences in the tensile strength among the different materials. Significant variability in tensile strength was observed among the suture materials in newtons (N). PGLA exhibited the highest mean tensile strength (38.7 N), followed closely by PDO (37.1 N), whereas silk displayed the lowest tensile strength (32.8 N). Comparative analysis revealed significant differences in the tensile strength among the materials (p < 0.001). This study provides valuable insights into the mechanical properties of the suture materials commonly used in oral surgery. These findings underscore the importance of considering tensile strength when selecting suture materials for specific clinical scenarios, thereby optimizing wound closure techniques and improving patient outcomes.

Combining red photobiomodulation therapy with polydioxanone threads for wrinkle reduction in the glabella region: A randomized, controlled, double-blind clinical trial.

The combination of polydioxanone (PDO) threads with other technologies has garnered significant interest for rejuvenation purposes. Photobiomodulation (PBM) has the potential to improve patient comfort and recovery after minimally invasive rejuvenation protocols and also contribute to the overall efficacy of these procedures, fostering an integrative approach to cutaneous rejuvenation. The objective os this work was to investigate concurrent application of PDO threads and red LED PBM on glabellar static wrinkles, in a parallel randomized sham-controlled trial. Forty individuals with Glogau aging classification levels 3 and 4, static glabellar wrinkles, and no significant comorbidities received PDO threads applied along glabellar line. Effective PBM group received 1.35 J and 630 nm red LED light punctually along threads, twice weekly for nine sessions over 30 days. The outcome measures were swelling assessment, dermal thickness and PDO thread degradation via linear ultrasound. No swelling was detected 24 h post-PDO thread application, hindering PBM effect assessment. PDO threads induced dermal thickening; no added effect with PBM. No significant difference in thread hydrolysis between groups, though some ultrasound records inconclusive on thread presence. The absence of swelling may stem from various factors, including the timing of post-procedure swelling assessment, operator proficiency in thread application, and procedural characteristics. No evidence supports the notion that PBM augments dermal thickening, however other light parameters should be studied. Insufficient data to demonstrate PBM's effectiveness in controlling post-procedure swelling. Combination of PBM with PDO thread application doesn't enhance dermal thickening, nor accelerate thread degradation at the parameters used here.

The Efficacy of the Absorbable Polydioxanone (PDO) Thread Lift in Lower Face (Marionette Line) Rejuvenation

The Efficacy of the Absorbable Polydioxanone (PDO) Thread Lift in Lower Face (Marionette Line) Rejuvenation

Volumizing Threads (Jamber) in the Midface and Managing Side Effects: Clinical Cases.

The clinical application of polydioxanone (PDO) threads, traditionally utilized for tissue lifting, is now being explored for its volumizing effects in midface rejuvenation. The novel approach involves employing PDO volumizing threads to achieve physical augmentation akin to a "solid filler." The study introduces a more convenient insertion method for these threads, prioritizing ease and efficacy. Clinical cases demonstrate the efficacy of volumizing threads in addressing midface concerns, such as nasolabial folds and midcheek grooves. Additionally, the integration of volumizing threads to provide support in sagging areas is examined for achieving natural-looking enhancements. While highlighting positive outcomes, potential side effects like thread protrusion are addressed, along with strategies for their mitigation. Volumizing threads are presented as a suitable procedure for patients wary of traditional fillers or seeking subtle enhancements, with the recommendation of combining them with cog threads for those desiring more pronounced changes in facial contour. In summary, volumizing thread offers a minimally invasive alternative with fewer side effects for midface rejuvenation.

Lower Blepharoplasty with Mid-Face Elevation: A Polydioxanone (PDO) Barbed Suture Loop for Lid-Cheek Junction Blending.

Anti-aging in the lower eyelid-cheek junction area has always been the most widely sought cosmetic surgery. However, orbital fat removal or a midcheek fat pad lift alone does not achieve the best results. This study describes a new technique of lower blepharoplasty combined with a midcheek lift performed using a polydioxanone barbed suture loop based on the entire anatomy of the lower eyelid-cheek junction area. We report our experience with lower blepharoplasty combined with a midcheek lift, covering 38 procedures performed over the past 3 years. We reviewed the technique and results and described the various indications for which the new technique is suitable. The efficacy of the surgeries was delineated using both 3D volume calculation and graphic pictures. All patients demonstrated significant rejuvenation of the lower eyelid with the elimination of the eyebags, elevation of the lid-cheek junction, and improvement of the nasolabial folds. All the patients were satisfied with the procedure. Complication rates were low, and lower lid retraction temporarily occurred in 3% of patients. This new method of lower blepharoplasty with midcheek elevation is safe, effective, convenient, and long-lasting. The technique is more doctor-friendly, recovery is quick, and complications are minimized. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Further experience with polydioxanone airway stents in children

AbstractIntroductionThe aims of this study were to update our experience with biodegradable polydioxanone (PDO) airway stents in children, focusing on effectiveness and safety, and to analyze the factors involved in the different outcomes observed.Materials and MethodsRetrospective study of patients managed with PDO stents from 2012 to 2023. Variables collected: demographics, comorbidities, indication, clinical baseline, stent size, location, complications, clinical outcome, and time of follow‐up. Statistical analyses were performed to detect the eventual contribution of variables in the different outcomes observed.ResultsFifty‐four PDO stents were placed in 26 patients (median age, 4 months). All showed severe symptoms of central airway obstruction due to tracheomalacia in nine patients, bronchomalacia five, tracheobronchomalacia 10, and tracheal stenosis two. Stent placement was uneventful in every case: 29 stents in the trachea and 25 in the main bronchi. 53.8% of patients needed successive stenting, and all exhibited comorbidities. Complete clinical resolution was observed in eight cases (30.7%), partial improvement in 13 (50%), unchanged in 4 (15.3%), and worsened in one. Age had a significant positive impact on outcome (6 vs. 3 months; p = 0.024). Additionally, smaller stents were associated with a better outcome (20 vs. 26 mm; p = 0.044). Granulation tissue was the most frequent complication (34.6%). Five patients (19.2%) died due to severe comorbidities, follow‐up was complete in survivors (median, 58 months).ConclusionsPDO stents are safe and effective when dealing with severe tracheobronchial obstruction. Stent‐related granulation tissue continues to be a relevant matter of concern. This issue, together with increased degradation times, deserves further research.

In Vitro Study of Tensile Strength Comparison of Selected Nonabsorbable and Absorbable Suture Materials after Immersion in 0.12% Chlorhexidine Gluconate.

To compare the tensile strength (TS) of absorbable and nonabsorbable suture materials after immersion in 0.12% chlorhexidine gluconate. Six 4-0-gauge suture materials were used, namely silk (S), polypropylene (PP), polyamide 6 (PA6), polyglactin 910 (PG910), poliglecaprone 25 (PL25), and polydioxanone (PDX). A total of 540 suture materials were divided equally (90) into six groups and tested. These materials were divided into a nonimmersed condition (10) and two thermostatically controlled immersion media (40 each), using artificial saliva for the control group (CG) and 0.12% chlorhexidine gluconate for the test group (TG). The specimens were tied to prefabricated rubber rods before immersion and removed at the testing timepoint. By using a universal testing machine (Instron 5566) with hooks attached, a hook-mounted specimen TS testing was performed on days 0, 1, 3, 7, and 14 at a 10 mm/min crosshead speed until the material was stretched to failure, and the maximum TS was recorded in Newtons (N). The continuous variables were taken as the mean and standard deviation across the six study groups to assess the significance at α = 0.05. A two-factor analysis of variance (ANOVA) was performed to assess the TSs over time in different media. A Bonferroni correction was performed when the data were statistically significant according to a two-factor ANOVA. Intragroup statistical comparisons were performed by repeated ANOVA for each study group. All data were analyzed using SPSS 26. The suture material TS analysis showed that nonabsorbable suture materials maintained their TS throughout the study; silk exhibited different behaviors, decreasing in TS from baseline to day 1 and maintaining its TS until day 14. All absorbable suture materials decreased in TSs by day 14. The silk and PG910 samples in the TG performed significantly better than those in the CG. Prescribing 0.12% chlorhexidine gluconate as a postsurgical mouth rinse is safest when silk and PG910 are the optimal suture materials.

Electrospun nanofibrous scaffolds as a platform to reduce melanoma tumour growth, recurrence, and promote post-resection wound repair

Wound healing following skin tumour surgery still remains a major challenge. To address this issue, polysaccharide-loaded nanofibrous mats have been engineered as skin patches on the wound site to improve wound healing while simultaneously eliminating residual cancer cells which may cause cancer relapse. The marine derived polysaccharides kappa-carrageenan (KCG) and fucoidan (FUC) were blended with polydioxanone (PDX) nanofibers due to their inherent anti-cancer activity conferred by the sulphate groups as well as their immunomodulatory properties which can reduce inflammation resulting in accelerated wound healing. KCG and FUC were released sustainably from the blend nanofibers via the Korsmeyer-Peppas kinetics. MTT assays, live/dead staining and SEM images demonstrated the toxicity of KCG and FUC towards skin cancer MP 41 cells. In addition, MP 41 cells showed reduced metastatic potential when grown on KCG or FUC containing mats. Both KCG and FUC were non- cytotoxic to healthy L 929 fibroblast cells. In vivo studies on healthy Wistar rats confirmed the non-toxicity of the nanofibrous patches as well as their improved and scarless wound healing potential. In vivo studies on tumour xenograft model further showed a reduction of 7.15 % in tumour volume in only 4 days following application of the transdermal patch.

Transduction and Genome Editing of the Heart with Adeno-Associated Viral Vectors Loaded onto Electrospun Polydioxanone Nonwoven Fabrics.

In this study, we introduce electrospun polydioxanone (PDO) nonwoven fabrics as a platform for the delivery of adeno-associated virus (AAV) vectors for transduction and genome editing by adhering them to organ surfaces, including the heart. AAV vectors were loaded onto the PDO fabrics by soaking the fabrics in a solution containing AAV vectors. In vitro, the amount of AAV vectors loaded onto the fabrics could be adjusted by changing their concentration in the solution, and the number of cells expressing the green fluorescent protein (GFP) encoded by the AAV vectors increased in correlation with the increasing amount of loaded AAV vectors. In vivo, both transduction and genome editing resulted in the observation of GFP expression around AAV vector-loaded PDO fabrics attached to the surfaces of mouse hearts, indicating effective transduction and expression at the target site. These results demonstrate the great potential of electrospun PDO nonwoven fabrics carrying therapeutic AAV vectors for gene therapy.

Effect of poly-L-lactic acid and polydioxanone biostimulators on type I and III collagen biosynthesis.

Safe, effective, and biocompatible minimally invasive procedures with the potential to stimulate collagen production have been made to recover dermal thickness and skin quality. The main of this animal model experiment was to observe the effect of poly-L-lactic acid (PLLA) and polydioxanone (PDO) biostimulators in collagen I and III after hypodermal injection. Sixteen adult female rats (Wistar) were randomized into four groups and had dorsal treatment with: G1: hypodermic subcision (HS) only; G2: HS and PLLA hypodermic injection (HI), G3: HS and PDO HI; G4: Control, with no treatment. In histochemical, it was observed hypodermal and dermal tissue in more organized thickness in G3 and in G4 when compared to G1 and G2. There was few difference in G1 compared to G4. The tissue of G2 showed irregularities in the arrangement of collagen fibers, less defined structure and lower distribution of type I collagen compared to the other groups. There is a greater tendency for the proportions of type III collagen among tissues treated with both biostimulators (G2 and G3). PLLA and PDO had relatively similar percentages of collagen when compared to G4. The amount of type I collagen was higher in tissues treated with subcision, while type III collagen was higher in tissues treated with both biostimulators. G3 showed better performance in collagen production, although small, when compared with G2.

An evaluation of the effectiveness of 'ULTRACOL 200' in enhancing nasolabial fold wrinkles through cutaneous repair.

Injectable filler, a nonsurgical beauty method, has gained popularity in rejuvenating sagging skin. In this study, polydioxanone (PDO) was utilized as the main component of the ULTRACOL200 filler that helps stimulate collagenesis and provide skin radiant effects. The study aimed to evaluate and compare the effectiveness of ULTRACOL200 with other commercialized products in visually improving dermatological problems. Herein, 31 participants aged between 20 and 59 years were enrolled in the study. 1mL of the testing product, as well as the quantity for the compared groups was injected into each participants face side individually. Subsequently, skin texture and sunken volume of skin were measured using ANTERA 3D CS imaging technology at three periods: before the application, 4weeks after the initial application, and 4weeks after the 2nd application of ULTRACOL200. The final results of skin texture and wrinkle volume evaluation consistently demonstrated significant enhancement. Consequently, subjective questionnaires were provided to the participants to evaluate the efficacy of the testing product, illustrating satisfactory responses after the twice applications. The investigation has contributed substantially to the comprehension of a PDO-based filler (ULTRACOL200) for skin enhancement and provided profound insight for future clinical trials.

Advanced Facial Rejuvenation: Synergistic Effects of Lower Blepharoplasty and Ultrasound Guided Mid-Face Lift Using Polydioxanone (PDO) Threads

BackgroundTraditional facial aging surgeries have risks and extended recovery times, leading to a demand for minimally invasive alternatives. PDO (polydioxanone) threads, which are absorbable sutures that stimulate collagen production and tissue contraction, offer improved aesthetic outcomes. This paper evaluates the combined use of PDO thread mid-cheek lift and lower blepharoplasty for facial rejuvenation.MethodsThis retrospective study compared outcomes in patients undergoing lower blepharoplasty combined with a mid-face lift using PDO threads versus those undergoing only lower blepharoplasty. Focused on individuals with baggy lower eyelids and pronounced nasolabial folds, outcome measures included the Modified Fitzpatrick wrinkle scale, Allergan® midface volume deficit scale, Width of inter zygomatic distance, Patient and Observer Scar Assessment Scale, and patient satisfaction questionnaires, assessed at baseline, 3 months, and 1 year postoperatively.ResultsThe combined procedure demonstrated superior aesthetic outcomes and higher patient satisfaction compared to lower blepharoplasty alone. Improvements were more significant in wrinkle reduction, midface volume, and inter-zygomatic distance in the combined procedure group. Although the combined procedure had a longer mean operation time, scar assessment scores were similar between both groups, with no complications reported.ConclusionThe combination of lower blepharoplasty and mid-face lift using PDO threads is a comprehensive and effective approach for facial rejuvenation. It significantly enhances wrinkle reduction, mid-face lifting, and patient satisfaction. Ultrasound-guided thread lifting, a method of assessing and performing mid-face lifting, proves to be safe and efficient. This approach holds promise as a future option in cosmetic anti-aging surgery, presenting a minimally invasive alternative with natural-looking results and reduced downtime.Level of Evidence IIThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://link.springer.com/journal/00266.

Biodegradable polydioxanone stents: histologic and structural effects in an experimental model of tracheal stenosis.

To evaluate the biologic impact of polydioxanone (PDO) stenting in an animal model of inflammatory tracheal stenosis (TS). Additionally, to compare these results with those obtained in the same model without a stent and after placing one PDO stent in a healthy trachea. 40 adult NZ rabbits were distributed into 3 groups: Group A, 8 animals with a healthy trachea and a PDO stent; group B, 17 rabbits with a TS and no stent; and group C, 15 animals with TS and a PDO stent. Histopathological studies included Masson's trichrome staining for submucosal fibrosis and Safranin O to assess structural integrity of cartilage. Morphometric analyses were performed in the 3 groups. Stent placement was successful in every case. Histological studies did not show a significant increase in tracheal wall collagen area and cartilage structure was not modified in those rabbits with a PDO stent, even in a TS scenario. Stent implantation permitted recovery of normal tracheal lumen levels in the TS model. PDO stenting in the normal trachea and in a model of TS neither caused increase in the collagen matrix nor modification of the cartilaginous support. Additionally, radial force exhibited by PDO stents was effective in restoring normal tracheal lumen when placed in a stenotic lesion. These findings suggest that they may be safe and useful in the setting of an acquired TS.

Polydioxanone Enhances Bone Regeneration After Resection and Reconstruction of Rat Femur with rhBMP2.

The aim of this study was to assess the bone regeneration potential of a polydioxanone (PDO) scaffold together with recombinant human bone morphogenetic protein-2 (rhBMP-2) for the reconstruction of large bone defect. In total, 24 male rats (6 months old) were subjected to bilateral femoral stabilization using titanium plates to create a 2 mm gap, and reconstruction using rhBMP-2 (Infuse®; 3.25 μg). The bone defects were covered with PDO (PDO group), or with titanium mesh (Ti group). Animals were euthanized on days 14 and 60. Simultaneously, 16 rats received PDO and Ti in their dorsum for the purpose of biocompatibility analysis at 3, 5, 7, and 10 days postoperatively. X-ray densitometry showed a higher density in the PDO group on day 14. On day 60, coverage of the bone defect with PDO showed a larger quantity of newly formed bone than that found for the Ti group, a lower inflammatory infiltrate value, and a more significant number of blood vessels on day 14. By immunohistochemical assessment, runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) showed higher labeling on day 14 in the PDO group. On day 60, bone morphogenetic protein-2 (BMP-2) showed higher labeling in the PDO group, whereas Ti showed higher labeling for osteoprotegerin, nuclear factor kappa B ligand-activating receptor, RUNX2, and OCN. Furthermore, biocompatibility analysis showed a higher inflammatory response in the Ti group. The PDO scaffold enhanced bone regeneration when associated with rhBMP-2 in rat femur reconstruction. Impact statement Regeneration of segmental bone defects is a difficult task, and several techniques and materials have been used. Recent advances in the production of synthetic polymers, such as polydioxanone (PDO), produced by three-dimensional printing, have shown distinct characteristics that could improve tissue regeneration even in an important bone defect. The present preclinical study showed that PDO membranes used as scaffolds to carry recombinant human bone morphogenetic protein-2 (rhBMP-2) improved bone tissue regeneration by more than 8-fold when compared with titanium mesh, suggesting that PDO membranes could be a feasible and useful material for use in guided bone regeneration. (In English, viable is only used for living creatures capable of sustaining life.