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

OBJECTIVE: 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. METHODOLOGY: 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. RESULTS: 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. CONCLUSION: G3 showed better performance in collagen production, although small, when compared with G2.

Horizontal necklines correction with absorbable braided polydioxanone threads: Case series.

INTRODUCTION: The prevalence of horizontal neck lines as a cosmetic concern is widely acknowledged, yet the available treatment options are limited, and no studies have investigated the use of polydioxanone-barbed threads. These threads, characterized by a finely braided structure, function as a scaffold to attract regenerative factors and facilitate the migration and proliferation of cells. This study aims to evaluate the outcomes of concurrent application of braided polydioxanone-barbed threads for addressing horizontal neck wrinkles. METHODOLOGY: A retrospective case series involving four female participants (aged 41, 43, 45, and 46) treated with polydioxanone-barbed threads for horizontal neck wrinkles between January 2023 and July 2023 was conducted. Adult patients were assessed at an 8-week follow-up, revealing a significant reduction in wrinkle intensity based on the Horizontal Neck Wrinkle Severity Scale. RESULTS: The analysis of horizontal neck lines demonstrated a notable decrease in wrinkle intensity according to the Horizontal Neck Wrinkle Severity Scale at the 8-week mark, and this improvement maintained statistical significance. Both patient Global Aesthetic Improvement Scale (GAIS) scores (90%-100%) and physician GAIS scores (100%) were rated as excellent. CONCLUSION: The subdermal application of polydioxanone-barbed threads for horizontal neck lines proves to be a secure and efficacious approach for treating horizontal neck wrinkles, with no observed Tyndall effect. This technique shows promise for rejuvenating the skin in the horizontal neckline region.

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

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Evaluation of Physical Properties of Coated Polydioxanone Threads.

BACKGROUND: Using a thread for wound closure promotes healing and minimizes contamination by foreign substances. Threads have also been employed in esthetic surgery; however, functional threads that can improve wrinkles and rejuvenate the skin are required. OBJECTIVE: To evaluate the suitability of polydioxanone threads coated with polyethylene glycol, hyaluronic acid, and amino acids for use in the medical field because such formulations are expected to promote regeneration and collagen synthesis. MATERIALS AND METHODS: Physical properties (diameter [ n = 20], tensile strength [ n = 20], strength retention rate [ n = 10], and scanning electron microscopy images) and cytotoxicity (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays) of polydioxanone threads coated with polyethylene glycol, hyaluronic acid, and amino acids were assessed and compared with those of uncoated polydioxanone threads. Analyses were performed using IBM SPSS Statistics (Statistical significance; p values <.05). RESULTS: The size standards for tensile strength (≥63.5 N) and diameter (average 0.570-0.610 mm) were met. There were no differences in the physical properties of the coated and uncoated threads; however, the biocompatibility of coated threads was high owing to low cytotoxicity. CONCLUSION: Threads coated with materials that can promote regeneration are suitable for use in the medical field.

Alleviation of peripheral sensitization by quadriceps insertion of cog polydioxanone filaments in knee osteoarthritis rats.

A recently established therapeutic strategy, involving the insertion of biodegradable cog polydioxanone filaments into the quadriceps muscles using the Muscle Enhancement and Support Therapy (MEST) device, has demonstrated significant efficacy in alleviating knee osteoarthritis (OA) pain. This study investigated changes in peripheral sensitization as the potential mechanism underlying MEST-induced pain relief in monoiodoacetate (MIA) induced OA rats. The results revealed that MEST treatment potently reduces MIA-induced sensitization of L3/L4 dorsal root ganglion (DRG) neurons, the primary nociceptor pathway for the knee joint. This reduction in DRG sensitization, as elucidated by voltage-sensitive dye imaging, is accompanied by a diminished overexpression of TRPA1 and NaV1.7, key nociceptor receptors involved in mechanical pain perception. Importantly, these observed alterations strongly correlate with a decrease in mechanically-evoked pain behaviors, providing compelling neurophysiological evidence that MEST treatment alleviates OA pain by suppressing peripheral sensitization.

Temporoparietal Fascia Graft and Polydioxanone Plate Repair of Nasal Septal Perforation.

BACKGROUND: Surgical repair of septal perforations has been historically cumbersome. Recently described techniques utilizing interposition grafting with polydioxanone (PDS) plates wrapped in a temporoparietal fascia (TPF) graft have reported successful closure in 90% to 100% of cases. Our objective is to expand the investigation into the use of interposition grafts of polydioxanone plates combined with a temporoparietal fascia graft for nasal septal perforation repair. METHODS: Retrospective review of the medical record was performed for all septal perforation repairs using the TPF-PDS plate interposition graft technique from August 1, 2017 to March 1, 2021 at the University of Iowa. Minimum post-operative follow-up was 1 month. RESULTS: Our series included 31 patients with symptomatic nasal septal perforations. Thirteen patients underwent open while 18 patients underwent endonasal graft placement. The mean perforation size was 1.49 cm2. The mean post-operative follow-up was 11.5 months. CONCLUSIONS: Repair of symptomatic nasal septal perforations using an interposition graft of polydioxanone plate wrapped in temporoparietal fascia demonstrated an overall success rate of 90%.

Rate of Vaginal Cuff Dehiscence When Using Vicryl (Poliglactyn 910) Compared to PDS (Polydioxanone) for Vaginal Cuff Closure in Laparoscopic Hysterectomy.

Objective: To compare the vaginal cuff dehiscence (VCD) rates using Vicryl (Poliglactyn 910) and Polydioxanone (PDS) in patients who underwent laparoscopic hysterectomy. Materials and methods: A retrospective, monocentric study was conducted, including all patients undergoing laparoscopic hysterectomy at the Department of Obstetrics and Gynaecology, Azienda di Rilievo Nazionale e di Alta Specializzazione (ARNAS) Garibaldi Nesima, Catania, between January 2014 and December 2021. Patients underwent hysterectomy for benign gynecologic pathologies (endometriosis, leiomyomas, or benign pelvic pathologies) or malignant gynecologic pathologies (endometrium cancer, complex endometrial hyperplasia, ovarian cancer, cervix cancer, or uterine carcinosarcoma). The Z-score calculation was performed to find eventual statistically significant differences between the two populations regarding VCD rates. Results: Laparoscopic vaginal cuff closure was performed, with Vicryl sutures in 202 patients and PDS sutures in 184 women. Demographic and baseline characteristics were not significantly different in the two groups. VCD occurred in three patients in the Vicryl group and did not occur in the PDS group. The three cases of VCD were precipitated by intercourses that occurred within 90 days of surgery. However, there was not a significant statistical difference between the two groups regarding VCD (p = 0.09). Conclusions: Vicryl and PDS sutures seem to be similar for vaginal cuff closure in laparoscopic hysterectomy. The VCD rate was low, and the observed differences between the Vicryl and PDS groups did not reach statistical significance. Further research through prospective studies is essential.

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.

Electrospun polydioxanone/fucoidan blend nanofibers loaded with anti-cancer precipitate from Jaspis diastra and paclitaxel: Physico-chemical characterization and in-vitro screening.

Nanofibers for drug delivery systems have gained much attention during the past years. This paper describes for the first time the loading of a bioactive precipitate (JAD) from the marine sponge Jaspis diastra in PDX and fucoidan-PDX. JAD was characterized by LC-MS/MS and the major component was jaspamide (1) with a purity of 62.66 %. The cytotoxicity of JAD was compared with paclitaxel (PTX). JAD and PTX displayed IC50 values of 1.10 ± 0.7 µg/mL and 0.21 ± 0.12 µg/mL on skin fibroblasts L929 cells whilst their IC50 values on uveal MP41 cancer cells, were 2.10 ± 0.55 µg/mL and 1.38 ± 0.68 µg/mL, respectively. JAD was found to be less cytotoxic to healthy fibroblasts compared to PTX. JAD and PTX loaded scaffolds showed sustained release over 96 h in physiological medium which is likely to reduce the secondary cytotoxic effect induced by JAD and PTX alone. The physico-chemical properties of the loaded and unloaded scaffolds together with their degradation and action on tumor microenvironment by using L929 and MP41 cells were investigated. JAD and PTX at a concentration of 0.5 % (drug/polymer, w/w) in the electrospun mats prevented growth and proliferation of L929 and MP41 cells. Co-culture of L929 and MP41 showed that the JAD and PTX loaded mats inhibited the growth of both cells and caused cell death.

Strength of small-bites abdominal wall closure using different suturing methods and materials in an experimental animal model.

PURPOSE: Using small instead of large bites for laparotomy closure results in lower incidence of incisional hernia, but no consensus exists on which suture material to use. This study aimed to compare five different closure strategies in a standardized experimental setting. METHODS: Fifty porcine abdominal walls were arranged into 5 groups: (A) running 2/0 polydioxanone; (B) interlocking 2/0 polydioxanone; (C) running size 0 barbed polydioxanone; (D) running size 0 barbed glycolic acid and trimethylene carbonate; (E) running size 0 suturable polypropylene mesh. The small-bites technique was used for linea alba closure in all. The abdominal walls were divided into a supra- and infra-umbilical half, resulting in 20 specimens per group that were pulled apart in a tensile testing machine. Maximum tensile force and types of suture failure were registered. RESULTS: The highest tensile force was measured when using barbed polydioxanone (334.8 N ± 157.0), but differences did not reach statistical significance. Infra-umbilical abdominal walls endured a significantly higher maximum tensile force compared to supra-umbilical (397 N vs 271 N, p < 0.001). Barbed glycolic acid and trimethylene carbonate failed significantly more often (25% vs 0%, p = 0.008). CONCLUSION: Based on tensile force, both interlocking and running suture techniques using polydioxanone, and running sutures using barbed polydioxanone or suturable mesh, seem to be suitable for abdominal wall closure. Tensile strength was significantly higher in infra-umbilical abdominal walls compared to supra-umbilical. Barbed glycolic acid and trimethylene carbonate should probably be discouraged for fascial closure, because of increased risk of suture failure.

Suturing with or without surgical glue is superior to surgical glue alone for sealing ex vivo swine gallbladders.

OBJECTIVE: To assess the effectiveness of various sealing techniques in cholecystotomies under maximum intraluminal pressure stress using an ex vivo swine model. SAMPLE: 30 gallbladders from different animals were used. METHODS: The experiment was conducted ex vivo, with the formation of 3 groups, each comprising 10 samples. Group 1 utilized a traditional single-layer Cushing suture made from polydioxanone material. Group 2 employed a single layer of Cushing suture, also made from polydioxanone material, but in conjunction with surgical glue (n-butyl cyanoacrylate). Group 3 relied solely on the use of surgical glue (n-butyl cyanoacrylate) for sealing the edges of the surgical wound. The intraluminal pressure was gauged with a pressure transducer. RESULTS: The maximum intraluminal pressures (mean ± SD) sustained in G1, G2, and G3 were, respectively, 48.70 ± 21.32 mm Hg, 110.90 ± 37.52 mm Hg, and 10.9 ± 4.07 mm Hg. Comparisons between groups showed that G2 supported significantly higher pressures (56.1% higher) than G1 (P < .001) and G3 (90.2% higher; P < .001). When G1 was compared with G3, a significantly higher pressure (77.6%) was also observed (P < .01). CLINICAL RELEVANCE: The study's conclusions demonstrated the safest suture techniques for the gallbladder and provided advice regarding the use of surgical glue.

Biodegradable Cardiac Occluder with Surface Modification by Gelatin-Peptide Conjugate to Promote Endogenous Tissue Regeneration.

Transcatheter intervention has been the preferred treatment for congenital structural heart diseases by implanting occluders into the heart defect site through minimally invasive access. Biodegradable polymers provide a promising alternative for cardiovascular implants by conferring therapeutic function and eliminating long-term complications, but inducing in situ cardiac tissue regeneration remains a substantial clinical challenge. PGAG (polydioxanone/poly (l-lactic acid)-gelatin-A5G81) occluders are prepared by covalently conjugating biomolecules composed of gelatin and layer adhesive protein-derived peptides (A5G81) to the surface of polydioxanone and poly (l-lactic acid) fibers. The polymer microfiber-biomacromolecule-peptide frame with biophysical and biochemical cues could orchestrate the biomaterial-host cell interactions, by recruiting endogenous endothelial cells, promoting their adhesion and proliferation, and polarizing immune cells into anti-inflammatory phenotypes and augmenting the release of reparative cytokines. In a porcine atrial septal defect (ASD) model, PGAG occluders promote in situ tissue regeneration by accelerating surface endothelialization and regulating immune response, which mitigate inflammation and fibrosis formation, and facilitate the fusion of occluder with surrounding heart tissue. Collectively, this work highlights the modulation of cell-biomaterial interactions for tissue regeneration in cardiac defect models, ensuring endothelialization and extracellular matrix remodeling on polymeric scaffolds. Bioinspired cell-material interface offers a highly efficient and generalized approach for constructing bioactive coatings on medical devices.

Comparative In Vivo Study of Solid-Type Pure Hyaluronic Acid in Thread Form: Safety and Efficacy Compared to Hyaluronic Acid Filler and Polydioxanone Threads.

INTRODUCTION: Although various products are commonly used for skin rejuvenation, solid-type hyaluronic acid (HA) as an injectable form has not been researched or utilized. This study aimed to demonstrate the safety and efficacy of solid-type HA in thread form, which differs from the conventional gel-type HA commonly used. METHOD: Solid-type HA threads, conventional HA fillers, and polydioxanone (PDO) threads were inserted into the dorsal subcutaneous layer of mice. Photographs were taken on days 0, 1, 3, and 7, and on day 7, the samples were harvested for histological analysis. Inflammatory reactions and detection of collagen were confirmed through tissue staining, and real-time PCR was conducted to quantify collagen synthesis. RESULTS: In the histological analysis, the PDO threads exhibited a greater inflammatory response compared to the HA threads. Masson's trichrome staining revealed a higher degree of collagen synthesis in the HA thread group compared to the HA filler group. While collagen type 1 expression was significantly higher in the PDO thread group than in the HA thread group, the HA thread group showed higher expression levels of collagen type 3. Furthermore, the PDO thread group demonstrated a statistically significant increase in TGF-ß1 compared to the HA group. CONCLUSION: This in vivo study demonstrated the stable application of solid-type pure HA threads and their potential for inducing collagen production, while also yielding a low inflammatory response. The findings highlight the promising applications of solid-type HA in the field of cosmetic dermatology. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 .

Experimental investigation of biostimulatory effects after polydioxanone thread insertion in a pig model.

BACKGROUND: Polydioxanone (PDO) threads have been widely used to tighten and lift the facial soft tissue. OBJECTIVE: This research aims to determine the collagenation and inflammation changes that occur in the adipose tissue over time when different types of threads are implanted. METHODS & MATERIALS: Three threads types, PDO, poly glycolic-co-lactic acid (PGLA), and nylon, were inserted in the subcutaneous fat of 12-month-old Bama miniature pigs. Collagen production and inflammatory response were evaluated by hematoxylin and eosin and Masson trichrome staining at 1, 4, 12, 24, and 48 weeks. RESULTS: The integrity of the PDO thread lasted up to 24 weeks with mild inflammation and collagen production. The PGLA thread integrity lasted until 12 weeks and had a strong inflammatory response. The nylon thread's integrity was maintained for 48 weeks and showed minor inflammation and collagen production. CONCLUSION: Our data suggest that PDO thread is the best choice for clinicians, as it has a mild action process with minimal irritation, moderate collagen production, a reasonable explanation time, with obvious bridging fibrous tissue, and thickening action for the superficial fascia.

Non-surgical rhinoplasty using polydioxanone threads.

OBJECTIVE: To demonstrate the effects of PDO threads non-surgical rhinoplasty on patients' quality of life (using FACE-Q Scale) and first impression assessments. METHODS: This is a prospective cohort study of 10 adult patients who sought non surgical rhinoplasty to improve tip rotation or reduce the appearance of a dorsal hump. All patients fulfilled the study's enrollment criteria. Prior to treatment, patients completed pre-treatment FACE-Q surveys and pre-treatment photos were obtained. Each patient was treated with the appropriate size and number of PDO threads necessary to achieve optimal correction result (OCR). Two weeks after treatment, the patient completed posttreatment FACE-Q surveys and posttreatment photos were obtained and analyzed. First impression surveys were created using pre- and posttreatment photos, and the survey was completed by 146 blinded evaluators. RESULTS: There was statistically significant improvement in the FACE-Q scores for social function (p = 0.02), psychological function (p = 0.0009) and satisfaction with nose (p = 0.0001). There was significant reduction in scores for appearance related psychosocial distress (p = 0.03). For the first impression surveys, there was a statistically significant improvement (p = 0.029) in the attractiveness scale posttreatment. Although not statistically significant, there was reduction of the dorsal hump (p = 0.15) and increase in the nasolabial angle (p = 0.48) and Goode's ratio (p = 0.16). There were no major adverse events or complications. CONCLUSION: This study shows that the PDO threads alone can be used safely to achieve minor nasal changes especially in tip rotation and appearance of dorsal hump, to improve patients' quality of life, and perceived attractiveness of treated patients.

A Hybrid Electrospun-Extruded Polydioxanone Suture for Tendon Tissue Regeneration.

Many surgical tendon repairs fail despite advances in surgical materials and techniques. Tendon repair failure can be partially attributed to the tendon's poor intrinsic healing capacity and the repurposing of sutures from other clinical applications. Electrospun materials show promise as a biological scaffold to support endogenous tendon repair, but their relatively low tensile strength has limited their clinical translation. It is hypothesized that combining electrospun fibers with a material with increased tensile strength may improve the suture's mechanical properties while retaining biophysical cues necessary to encourage cell-mediated repair. This article describes the production of a hybrid electrospun-extruded suture with a sheath of submicron electrospun fibers and a core of melt-extruded fibers. The porosity and tensile strength of this hybrid suture is compared with an electrospun-only braided suture and clinically used sutures Vicryl and polydioxanone (PDS). Bioactivity is assessed by measuring the adsorbed serum proteins on electrospun and melt-extruded filaments using mass spectrometry. Human hamstring tendon fibroblast attachment and proliferation were quantified and compared between the hybrid and control sutures. Combining an electrospun sheath with melt-extruded cores created a hybrid braid with increased tensile strength (70.1 ± 0.3N) compared with an electrospun only suture (12.9 ± 1 N, p < 0.0001). The hybrid suture had a similar force at break to clinical sutures, but lower stiffness and stress. The Young's modulus was 772.6 ± 32 MPa for the hybrid suture, 1693.0 ± 69 MPa for PDS, and 3838.0 ± 132 MPa for Vicryl, p < 0.0001. Hybrid sutures had lower overall porosity than electrospun-only sutures (40 ± 4% and 60 ± 7%, respectively, p = 0.0018) but had a significantly larger overall porosity and average pore diameter compared with surgical sutures. There were similar clusters of adsorbed proteins on electrospun and melt-extruded filaments, which were distinct from PDS. Tendon fibroblast attachment and cell proliferation on hybrid and electrospun sutures were significantly higher than on clinical sutures. This study demonstrated that a bioactive suture with increased tensile strength and lower stiffness could be produced by adding a core of 10 µm melt-extruded fibers to a sheath of electrospun fibers. In contrast to currently used sutures, the hybrid sutures promoted a bioactive response: serum proteins adsorbed, and fibroblasts attached, survived, grew along the sutures, and adopted appropriate morphologies.

Comparison of Polypropylene and Polydioxanone in the Hemitransdomal Suture: A Novel Rabbit Ear Cartilage Model.

BACKGROUND: Lower lateral cartilage reshaping is one of the basic steps in rhinoplasty. Hemitransdomal suture is frequently used for dome narrowing. Different suture materials can be used for hemitransdomal suture. In this study, we investigated the effectiveness of polypropylene and polydioxanone in hemitransdomal suture by designing a new experimental model in the rabbit ear cartilage. METHODS: Twelve young adult male New Zealand White rabbits were used. The bipedicled inverted-U-shaped cartilage was elevated in each ear of the rabbits. Two hemitransdomal sutures were applied using 5-0 polypropylene on one ear and 5-0 polydioxanone on the other ear randomly. A 5 mm high cartilage mound was created with two hemitransdomal sutures on each side. The sample size was twelve both in the polypropylene group and the polydioxanone group (n = 12). All animals were sacrificed after three months. Cartilage mound heights were measured. The samples were examined histologically regarding fibroadipose tissue, inflammation, foreign body granuloma, cartilage degeneration, and the presence of inclusion cyst. RESULTS: Cartilage mound height was significantly higher in the polypropylene group than in the polydioxanone group at the end of the third month [3.75 mm (± 0.68) vs. 3.03 mm (± 0.69); p < 0.05]. There was no significant difference between the two groups in histological analysis (p > 0.05). CONCLUSIONS: Polypropylene suture may be more effective in maintaining the shape given to the dome by hemitransdomal sutures in rhinoplasty. No Level Assigned This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266.

A preliminary investigation of the subcutaneous tissue reaction to a 3D printed polydioxanone device in horses.

BACKGROUND: A 3D printed self-locking device made of polydioxanone (PDO) was developed to facilitate a standardized ligation technique. The subcutaneous tissue reaction to the device was evaluated after implantation in ten horses of mixed age, sex and breed and compared to loops of poly(lactic-co-glycolic acid) (PLGA). In two of the horses, the implants were removed before closing the skin. The appearance of the implants and surrounding tissue was followed over time using ultrasonography. Implants were removed after 10 and 27 (± 1) days for histologic examination. RESULTS: On macroscopic inspection at day 10, the PDO-device was fragmented and the surrounding tissue was oedematous. On ultrasonographic examination, the device was seen as a hyperechoic structure with strong acoustic shadowing that could be detected 4 months post-implantation, but not at 7 months. Histology revealed a transient granulomatous inflammation, i.e., a foreign body reaction, which surrounded both PDO and PLGA implants. The type and intensity of the inflammation varied between individuals and tissue category. CONCLUSIONS: The 3D printed PDO-device caused a transient inflammatory reaction in the subcutaneous tissue and complete resorption occurred between 4 and 7 months. Considering the intended use as a ligation device the early fragmentation warrants further adjustments of both material and the 3D printing process before the device can be used in a clinical setting.

Comparison of incisional bursting strength of a bidirectional absorbable knotless suture material versus a standard continuous absorbable suture material for closure of the equine linea alba.

OBJECTIVE: To evaluate the use of bidirectional knotless barbed suture material for closure of the equine linea alba. STUDY DESIGN: Laboratory study. ANIMAL OR SAMPLE POPULATION: Adult light horse cadavers (n = 24). METHODS: A 25 cm incision was made through the linea alba, and a 200 L polyurethane bladder was positioned within the abdomen. The linea alba was closed either using USP2/EP5 bidirectional polydioxanone barbed suture or USP2/EP5 standard polydioxanone suture in a simple continuous pattern. Closure time was recorded for each suture type. The bladder was air-insufflated at 40 L/min, and the pressure at body wall failure recorded. The length of suture used for wound closure and wound failure modes were recorded. Suture length, closure time, bursting pressure, and failure modes were compared using Welch-Aspin t-tests. RESULTS: The incisional bursting pressure was comparable between the two groups (p > .05). Less suture material (p < .01) was required with the barbed suture than the standard suture. Closure time was less for the barbed suture than the standard suture (p < .01). Suture failure was the main failure mode in both groups (83% cases). CONCLUSIONS: Closure of the equine linea alba using bidirectional barbed suture material reduced the amount of foreign material in the wound and decreased closure time without compromising incisional strength. CLINICAL RELEVANCE: Bidirectional barbed suture material could be considered as an alternative to standard suture materials for closure of the equine line alba.