Mechanical comparison of 10 suture materials before and after in vivo incubation

Braided silk sutures coated with photoreduced silver nanoparticles for eradicating Staphylococcus aureus and Streptococcus mutans infections

BACKGROUND

Infections resulting from surgical procedures and wound closures continue to pose significant challenges in healthcare settings. To address this issue, the investigators have developed antibacterial non-resorbable braided silk sutures using in situ deposited silver nanoparticles (AgNPs) and investigated their efficacy in eradicating Staphylococcus aureus and Streptococcus mutans infections.

METHODS

The braided silk sutures were modified through a simple and efficient in situ photoreduction method, resulting in the uniform distribution of AgNPs along the suture surface. The synthesized AgNPs were characterized using scanning electron microscopy (SEM), dynamic light scattering analysis (DLS) and Fourier Transform Infrared Spectroscopy analysis (FTIR) confirming their successful integration onto the silk sutures. The antibacterial activity of the nanoparticle coated sutures were compared and evaluated with non-coated braided silk sutures through in vitro assays against both S. aureus and S. mutans.

RESULTS

The surface and cross-sectional analysis of the treated sutures revealed a uniform and homogeneous distribution of silver particles achieved through the photoreduction of silver solution. This observation confirms the successful coating of silver nanoparticles (AgNPs) on the sutures. The antimicrobial studies conducted, demonstrated significant reductions in bacterial colonies when exposed to the silver nanoparticle-coated sutures. Notably, the width of the inhibition zone surrounding the coated sutures remained consistently wide and stable for duration up to 7 days. This sustained and robust inhibitory effect against gram-positive bacteria, specifically S. aureus and S. mutans, serves as strong evidence of the antibacterial efficacy of the coated sutures.

CONCLUSION

The coating of silk sutures with AgNPs provided a significant and effective antibacterial capacity to the surgical sutures, with this activity being sustained for a period of 7 days. This suggests that AgNPs-in situ photoreduction deposited sutures have the potential to effectively manage S. aureus and S. mutans infections.

The effect of medical grade honey on tensile strength, strain, and Young's modulus of synthetic absorbable suture material used in equine surgery

BACKGROUND

Medical grade honey (MGH) has been introduced as a protective measure against surgical site infections in equine surgery, but the effect on suture material has not been investigated.

OBJECTIVE

To evaluate the effect of MGH on the tensile properties of three synthetic absorbable suture materials.

STUDY DESIGN

In vitro experiments.

METHODS

Ten strands of Polydioxanone USP 2 (PD2), Polyglactin 910 USP 2 (PG2) and Polyglecaprone USP 2-0 (PC2-0) were incubated 1, 7, 14, 21 and 28 days in MGH, phosphate-buffered saline (PBS), equine plasma (EP) and MGH mixed with equine plasma (HP). Mechanical testing was performed recording maximum load at failure (N), strain at failure and Young's modulus (N/mm2 ). The results were reported from a Welch or regular ANOVA.

RESULTS

PD2 in MGH had a significantly higher tensile strength compared to PD2 in EP (p < 0.05, mean difference (md) = 16.95 N, CI95% (9.19-24.70 N)) and PBS (p < 0.05, md = 14.48 N CI95% (6.73-22.23 N)) on day 7 and the remaining time points. PG2 incubated in MGH had a significantly higher tensile strength compared to EP (p < 0.05, md = 69.28 N CI95% (64.16-74.40 N)) and PBS (p < 0.05, md = 56.90 N CI95% (51.78-62.02 N)) until day 28. PC2-0 incubated in MGH had a significantly higher tensile strength compared to EP (p < 0.05 md = 12.40 N CI95% (4.59 N-20.20 N)) and PBS (p < 0.05 md = 11.23 CI95% (3.42-19.03 N)) on day 7 and the remaining time points.

MAIN LIMITATIONS

The sutures were unloaded during incubation and a single cycle to failure test was only performed, which does not reflect the in vivo environment where shear forces are present.

CONCLUSIONS

MGH did not negatively affect the tensile strength of the suture material and can safely be applied in contact with suture materials commonly used in equine surgery.

The Choice of the Most Appropriate Suture Threads for Pancreatic Anastomoses on the Basis of Their Mechanical Characteristics

The choice of the most appropriate suture threads for pancreatic anastomoses may play an important role in reducing the incidence of post-operative pancreatic fistula (POPF). The literature on this topic is still not conclusive. The aim of this study was to analyze the mechanical characteristics of suture materials to find the best suture threads for pancreatic anastomoses. A single-axial electromagnetic actuation machine was used to obtain the stress–deformation relationship curves and to measure both the ultimate tensile strength (UTS) and the Young’s modulus at the 0–3% deformation range (E0–3) of four different suture materials (Poliglecaprone 25, Polydioxanone, Polyglactin 910, and Polypropylene) at baseline and after incubation in saline solution, bile, and pancreatic juice for 1, 3, and 7 days. Polydioxanone and Polypropylene showed stable values of UTS and E0–3 in all conditions. Polyglactin 910 presented significant UTS and E0–3 variations between different time intervals in all types of liquids analyzed. Poliglecaprone 25 lost half of its strength in all biological liquids analyzed but maintained low E0–3 values, which could reduce the risk of lacerations of soft tissues. These results suggest that Polydioxanone and Poliglecaprone 25 could be the best suture materials to use for pancreatic anastomoses. In vivo experiments will be organized to obtain further confirmations of this in vitro evidence.

Canine ACL reconstruction with an injectable hydroxyapatite/collagen paste for accelerated healing of tendon-bone interface

Healing of an anterior cruciate ligament (ACL) autologous graft in a bone tunnel occurs through the formation of fibrovascular scar tissue, which is structurally and compositionally inferior to normal fibrocartilaginous insertion and thus may increase the reconstruction failure and the rate of failure recurrence. In this study, an injectable hydroxyapatite/type I collagen (HAp/Col Ⅰ) paste was developed to construct a suitable local microenvironment to accelerate the healing of bone-tendon interface. Physicochemical characterization demonstrated that the HAp/Col Ⅰ paste was injectable, uniform and stable. The in vitro cell culture illustrated that the paste could promote MC3T3-E1 cells proliferation and osteogenic expression. The results of a canine ACL reconstruction study showed that the reconstructive ACL had similar texture and color as the native ACL. The average width of the tunnel, total bone volume, bone volume/tissue volume and trabecular number acquired from micro-CT analysis suggested that the healing of tendon-bone interface in experimental group was better than that in control group. The biomechanical test showed the maximal loads in experimental group achieved approximately half of native ACL's maximal load at 24 weeks. According to histological examination, Sharpey fibers could be observed as early as 12 weeks postoperatively while a typical four-layer transitional structure of insertion site was regenerated at 48 weeks in the experimental group. The injectable HAp/Col Ⅰ paste provided a biomimetic scaffold and microenvironment for early cell attachment and proliferation, further osteogenic expression and extracellular matrix deposition, and in vivo structural and functional regeneration of the tendon-bone interface.

•

A stable and injectable HAp/Col I paste was designed, optimized and characterized.

•

The paste was applied in ACL reconstruction with an established standard operation procedure.

•

Provided the safety and efficacy evidence for ACL reconstruction, and healing of tendon-bone interface was accelerated.

Actively separated microneedle patch for sustained-release of growth hormone to treat growth hormone deficiency

Growth hormone deficiency (GHD) has become a serious healthcare burden, and presents a huge impact on the physical and mental health of patients. Here, we developed an actively separated microneedle patch (PAA/NaHCO₃-Silk MN) based on silk protein for sustained release of recombinant human growth hormone (rhGH). Silk protein, as a friendly carrier material for proteins, could be constructed in mild full-water conditions and ensure the activity of rhGH. After manually pressing PAA/NaHCO₃-Silk MN patch to skin for 1 min, active separation is achieved by absorbing the interstitial fluid (ISF) to trigger HCO₃ ^‒ in the active backing layer to produce carbon dioxide gas (CO₂). In rats, the MN patch could maintain the sustained release of rhGH for more than 7 days, and produce similar effects as daily subcutaneous (S.C.) injections of rhGH in promoting height and weight with well tolerated. Moreover, the PAA/NaHCO₃-Silk MN patch with the potential of painless self-administration, does not require cold chain transportation and storage possess great economic benefits. Overall, the PAA/NaHCO₃-Silk MN patch can significantly improve patient compliance and increase the availability of drugs, meet current unmet clinical needs, improve clinical treatment effects of GHD patients.

The clinical outcomes and complications of combined fixation with cannulated screws and the modified Pyrford technique for the treatment of transverse patellar fractures: a case series study

Background

Transverse patellar fractures can be fixed using various techniques. The purpose of the current study was to assess the clinical outcomes and complication rate of a combined fixation technique using cannulated screws and the modified Pyrford technique with nonabsorbable polyester sutures.

Methods and patients

Between January 2015 and February 2021, 26 transverse patellar fractures were fixed with this combined technique. Preoperative data were collected from patients with transverse patellar fractures who were followed up for at least 12 months. At each follow-up visit, plain radiographs were taken. At the 12-month postoperative follow-up, range of motion of the affected knee joint and clinical outcomes, as evaluated by the Bostman scoring system, were recorded.

Results

The average Bostman score at the 12-month postoperative follow-up was 28.3 ± 1.5. Furthermore, the average extension and flexion of the knee joint were 1.2 ± 2.1 and 125.6 ± 6.7 degrees, respectively. One patient experienced delayed bone union and one experienced superficial wound infection. There were no other postoperative complications. One patient required removal of the device for social-psychological reasons.

Conclusions

The combined fixation technique with cannulated screws and the modified Pyrford technique with suture materials produced excellent clinical outcomes and a low rate of complications in the treatment of transverse patellar fractures.

Absorbable versus nonabsorbable sutures for the Krackow suture repair of acute Achilles tendon rupture: a prospective randomized controlled trial

AIMS

Although absorbable sutures for the repair of acute Achilles tendon rupture (ATR) have been attracting attention, the rationale for their use remains insufficient. This study prospectively compared the outcomes of absorbable and nonabsorbable sutures for the repair of acute ATR.

METHODS

A total of 40 patients were randomly assigned to either braided absorbable polyglactin suture or braided nonabsorbable polyethylene terephthalate suture groups. ATR was then repaired using the Krackow suture method. At three and six months after surgery, the isokinetic muscle strength of ankle plantar flexion was measured using a computer-based Cybex dynamometer. At six and 12 months after surgery, patient-reported outcomes were measured using the Achilles tendon Total Rupture Score (ATRS), visual analogue scale for pain (VAS pain), and EuroQoL five-dimension health questionnaire (EQ-5D).

RESULTS

Overall, 37 patients completed 12 months of follow-up. No difference was observed between the two groups in terms of isokinetic plantar flexion strength, ATRS, VAS pain, or EQ-5D. No re-rupture was observed in either group.

CONCLUSION

The use of absorbable sutures for the repair of acute ATR was not inferior to that of nonabsorbable sutures. This finding suggests that absorbable sutures can be considered for the repair of acute ATRs. Cite this article: Bone Joint J 2022;104-B(8):938-945.

Degradation of internal fixation materials based on antibacterial and absorbable silk containing different gentamicin concentrations

Adding gentamicin to silk fibroin enhances both the antibacterial performance and degradation rate of silk-based materials. The increased material degradation rate can affect the strength of early internal fixation, resulting in internal fixation failure. This study sought to adjust the gentamicin concentration to control the material degradation rate, thereby better meeting clinical application requirements. The in vitro degradation, water absorption rate, and expansion rate of silk-based materials containing different gentamicin concentrations were studied. A gentamicin-loaded silk-based screw was implanted into the femurs of New Zealand rabbits. Micro-computed tomography was used to measure the screw diameter, which was then used to calculate the degradation rate. The specimens were stained with hematoxylin and eosin and Masson's trichrome. The in vitro results revealed increasing material degradation rates with increasing gentamicin concentration but no significant differences in water absorption rates with different gentamicin concentrations. The degradation rates of gentamicin-loaded (4 mg/g) silk-based rod-like materials were approximately 11.08% at three months in vitro and 9.4% in the animal experiment. The time for complete degradation was predicted from the fitting curve to be approximately 16 months. No inflammatory hyperplasia was observed in bone or soft tissue. The degradation and biocompatibility of the material containing 4 mg/g gentamicin meet clinical application requirements, and previous experimental results demonstrate good antibacterial performance of materials containing this gentamicin concentration.

Continuous Microfiber Wire Mandrel-Less Biofabrication for Soft Tissue Engineering Applications

Suture materials are the most common bioimplants in surgical and clinical practice, playing a crucial role in wound healing and tendon and ligament repair. Despite the assortment available on the market, sutures are still affected by significant disadvantages, including failure in mimicking the mechanical properties of the tissue, excessive fibrosis, and inflammation. This study introduces a mandrel-less electrodeposition apparatus to fabricate continuous microfiber wires of indefinite length. The mandrel-less biofabrication produces wires, potentially used as medical fibers, with different microfiber bundles, that imitate the hierarchical organization of native tissues, and tailored mechanical properties. Microfiber wire morphology and mechanical properties are characterized by scanning electron microscopy, digital image processing, and uniaxial tensile test. Wires are tested in vitro on monocyte/macrophage stimulation and in vivo on a rat surgical wound model. The wires produced by mandrel-less deposition show an increased M2 macrophage phenotype in vitro. The in vivo assessment demonstrates that microfiber wires, compared to the medical fibers currently used, reduce pro-inflammatory macrophage response and preserve their mechanical properties after 30 days of use. These results make this microfiber wire an ideal candidate as a suture material for soft tissue surgery, suggesting a crucial role of microarchitecture in more favorable host response.

A Complex In Vitro Degradation Study on Polydioxanone Biliary Stents during a Clinically Relevant Period with the Focus on Raman Spectroscopy Validation

Biodegradable biliary stents are promising treatments for biliary benign stenoses. One of the materials considered for their production is polydioxanone (PPDX), which could exhibit a suitable degradation time for use in biodegradable stents. Proper material degradation characteristics, such as sufficient stiffness and disintegration resistance maintained for a clinically relevant period, are necessary to ensure stent safety and efficacy. The hydrolytic degradation of commercially available polydioxanone biliary stents (ELLA-CS, Hradec Králové, Czech Republic) in phosphate-buffered saline (PBS) was studied. During 9 weeks of degradation, structural, physical, and surface changes were monitored using Raman spectroscopy, differential scanning calorimetry, scanning electron microscopy, and tensile and torsion tests. It was found that the changes in mechanical properties are related to the increase in the ratio of amorphous to crystalline phase, the so-called amorphicity. Monitoring the amorphicity using Raman spectroscopy has proven to be an appropriate method to assess polydioxanone biliary stent degradation. At the 1732 cm⁻¹ Raman peak, the normalized shoulder area is less than 9 cm⁻¹ which indicates stent disintegration. The stent disintegration started after 9 weeks of degradation in PBS, which agrees with previous in vitro studies on polydioxanone materials as well as with in vivo studies on polydioxanone biliary stents.

The Combined Use of Silicone and Green Braided Polyester ‎Suture (Ethibond) versus ‎Silicone or Ethibond Alone for Frontalis ‎Suspension Surgery in Children

Purpose

Patients and Methods

Results

Conclusion

Surface coating prolongs the degradation and maintains the mechanical strength of surgical suture in vivo

Biodegradable and absorbable sutures have been widely used in surgical procedures. However, for the repair of ligament and tendon injures, the biodegradable suture cannot provide sufficient mechanical support to close the wound for a long period of time which is important to completely heal the tissue. Herein, we develop a simple method that makes a surface coating to prolong the degradation of the suture in vivo. Polylactic acid (PLLA) and Polycaprolactone (PCL) were successfully coated to a commercial degradable polydioxanone (PDO) suture in this study, which was confirmed by Fourier transform infrared spectra (FTIR). Scanning electron microscopy (SEM) was used to observe the smooth surface of the coated sutures. Moreover, live/dead assay of human fibroblasts after co-culturing with the modified/unmodified sutures showed fairly good cellular activity. In vivo study demonstrates the degradation properties of sutures were significantly changed after the surface coating. The raw suture exhibited the fastest degradation in 12 weeks, showing significantly decline in mechanical strength. Interestingly, the PCL-coated suture was able to maintain more than 20% of its original tensile strength after 12 weeks' implantation. In addition, in vivo results of PCL-coated sutures also showed less inflammatory cell infiltration and less surface inflammation. These findings indicate the one step suture-coating method could be feasibly for the development of clinical equipment.

Comparison of double-strand braided polyester sutures tension band (Nice knot) with cable tension band in transverse patellar fractures

BACKGROUND

The tension band technique is the most common method for internal fixation of transverse patellar fractures. Titanium cable and high-strength sutures have been successfully applied in this treatment; however, few studies have compared the Nice knot technique using sutures with the standard cable technique. Whether the suture technique (Nice knot) provides preferable results compared with those of the cable technique is unclear.

METHODS

Forty patients with transverse patellar fractures participated in this study. Twenty patients underwent sutures tension band fixation (Nice knot), and the others were managed with cable tension bands. All patients were followed up at 1, 3, 6, and 12 months. Pain was measured by VAS scores, flexion and extension of the knee were measured in degrees by goniometry, and knee function was evaluated using the Böstman clinical grading scale.

RESULTS

The two groups had equal distributions in age, gender, injured side, and fracture classification. The mean operation time in the suture group was shorter (55.75±9.77 minutes versus 64.25±9.63 minutes). The VAS score was comparable in the two groups at the 1-month, 3-month, and 6-month follow-ups; however, the score was lower at 12 months postoperatively in the suture group (P=0.037). No significant difference was found in flexion, extension, Böstman score, or fracture healing time in either group (P>0.05). Postoperative complications were higher in the cable group (9 versus 2) (P = 0.031) but were mostly related to symptomatic soft tissue irritation.

CONCLUSION

The suture tension band technique using braided polyester nonabsorbable sutures tied with Nice knot was as effective as the cable tension band technique for transverse patellar fracture management. However, more convenient operations, less cost and fewer complications were found in suture fixation (Nice knot).

In Vivo Versus In Vitro Degradation of a 3D Printed Resorbable Device for Ligation of Vascular Tissue in Horses

A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo and the Young's modulus (E) and tensile strength at break (σ_b ) decreased by 28% and 54%, respectively. This is in contrast to in vitro aging, where no loss of mechanical properties is observed during the same period. The in vivo aged devices exhibit clear holes in the matrices after 28 days, while apparent cracks are observed first after 140 days in vitro. These results highlight the sensitivity of the degradation process of resorbable devices with regards to the interactions of the device with the surrounding environment (tissues) and demonstrate the importance of in vivo testing as compliment to in vitro testing before clinical use of devices.

A comparative microbiological study of polyglycolic acid and silk sutures in oral surgical procedures

INTRODUCTION

Bacterial adherence to silk and polyglycolic acid suture is similar. Literature has shown bacterial adhesion is lower degree in polyglycolic acid suture compared to silk, but tissue reaction was more in the polyglycolic acid suture. The aim of the study was to compare the bacteria adhered on the silk and polyglycolic acid sutures.

METHODOLOGY

Sixty two patients who fulfilled the inclusion criteria were included in the study and were divided equally into group A and group B. After intraoral surgical procedures the operated site was sutured either with 3-0 black silk or 3-0 polyglycolic acid sutures in group A and B respectively. On seventh day after irrigation with normal saline sutures were removed and one suture strand was transported to the Department of Microbiology to inoculate and identify the bacteria.

RESULTS

- 3-0 black silk exhibited a high degree of aerobic bacteria. The bacteria identified on the suture were Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus viridians, Enterobacter, Escherichia coli, Citrobacter and Klebseilla. In 3-0 polyglycolic acid suture Pseudomonas aeruginosa, E. coli, Streptococcus Viridians bacteria were identified.

DISCUSSION

- PGA showed fewer bacterial adherences compared to black silk. Fewer bacterial adherence and resorbable PGA makes a better choice for intra oral surgical procedures.

Bone Mesenchymal Stem Cells Contribute to Ligament Regeneration and Graft-Bone Healing after Anterior Cruciate Ligament Reconstruction with Silk-Collagen Scaffold

Anterior cruciate ligament (ACL) reconstruction was realized using a combination of bone mesenchymal stem cells (BMSCs) and silk–collagen scaffold, and an in vivo evaluation of this combination was performed. By combining type I collagen and degummed silk fibroin mesh, silk–collagen scaffolds were prepared to simulate ligament components. BMSCs isolated from bone marrow of rabbits were cultured for a homogenous population and seeded on the silk–collagen scaffold. In the scaffold and BMSC (S/C) group, scaffolds were seeded with BMSCs for 72 h and then rolled and used to replace the ACL in 20 rabbits. In the scaffold (S) group, scaffolds immersed only in culture medium for 72 h were used for ACL reconstruction. Specimens were collected at 4 and 16 weeks postoperatively to assess ligament regeneration and bone integration. HE and immunohistochemical staining (IHC) were performed to assess ligament regeneration in the knee cavity. To assess bone integration at the graft–bone interface, HE, Russell–Movat staining, micro-CT, and biomechanical tests were performed. After 4 weeks, vigorous cell proliferation was observed in the core part of the scaffold in the S/C group, and a quantity of fibroblast-like cells and extracellular matrix (ECM) was observed in the center part of the graft at 16 weeks after surgery. At 4 and 16 weeks postoperatively, the tenascin-C expression in the S/C group was considerably higher than that in the S group (4 w, p < 0.01; 16 w, p < 0.01). Furthermore, bone integration was better in the S/C group than in the S group, with histological observation of trabecular bone growth into the graft and more mineralized tissue formation detected by micro-CT (4 w, bone volume fraction (BV/TV), p = 0.0169, bone mineral density (BMD), p = 0.0001; 16 w, BV/TV, p = 0.1233, BMD, p = 0.0494). These results indicate that BMSCs promote ligament regeneration in the knee cavity and bone integration at the graft–bone interface. Silk–collagen scaffolds and BMSCs will likely be combined for clinical practice in the future.

Lead Macrodislodgement of a Subcutaneous Implantable Cardioverter-Defibrillator Results in a Reel Problem

Lead macrodislodgement is a rare complication of cardiac implantable electronic devices associated with patient-related risk factors. This paper outlines a case of reel syndrome secondary to device manipulation 3 months after subcutaneous implantable cardioverter-defibrillator implantation and describes the challenges with lead macrodislodgement diagnosis, mechanisms, and management. (Level of Difficulty: Beginner.).

The Effect of Absorbable and Non-absorbable Scleral Suture on Strabismus Surgery in the Rabbits

Purpose: To evaluate and compare the histopathological changes in a rabbit model, following strabismus surgery using either absorbable or non-absorbable suture materials. Methods: Superior rectus muscle recession was performed in rabbits using either an absorbable (Vicryl®) or non-absorbable (Prolene®) suture material. Hematoxylin-eosin staining was performed and histologic changes in the sclera were evaluated at the first, second, fourth, and eighth weeks, postoperatively. Moreover, the postoperative scleral thickness was measured and the postoperative pattern of arrangement of scleral fibers was analyzed. Results: Suture material-induced limited inflammatory reaction and formation of new vessels were observed in the study subjects, in the early postoperative phase, in both the Vicryl® and Prolene® groups. In the Vicryl® group, multinucleated giant cells were dominant during the inflammatory phase, and replacement by fibrotic scar tissues was observed. In the Prolene® group, the suture material was observed to be intact, and the inflammatory reactions around the sutures were observed to be less severe compared to the Vicryl® group. Meanwhile, neither group exhibited reduction in scleral thickness or irregular rearrangement of scleral fibers. Conclusions: The current histological study demonstrated that there was no significant postoperative scleral tissue changes after a strabismus surgery. Furthermore, the absorbable suture material was observed to induce inflammatory reactions of greater severity, compared to the non-absorbable suture material, in scleral tissues.

Influence of Hybridization on Tensile Behaviors of Non-Absorbable Braided Polymeric Sutures

This paper aims to investigate the effects of fiber hybridization technique on the mechanical behaviors of non-absorbable braided composite sutures. Fifteen types of hybrid braided sutures (HBSs) made of polyester (PET), polypropylene (PP), and polyamide 6 (PA6) are produced and tested to measure ultimate tensile strength (UTS), maximum strain, elastic modulus, and breaking toughness. Based on the results, it is observed that the suture material plays a significant role in the tensile and mechanical performance of HBSs, and they can be tailored through the different combinations of yarns according to the required mechanical properties. Experiments exhibit occurrence positive hybrid effect in both maximum strain and elastic modulus, and negative hybrid effect in UTS. The optimal tensile performance is associated with the hybrid structure comprising 75% PA6-12.5% PET-12.5% PP. This means the ternary structure with higher PA6 content along with PP and PET, demonstrates a synergistic effect. Thus, such a ternary composite structure is very promising for the design of novel non-absorbable sutures. Due to the absence of similar results in the specialized literature, this paper is likely to advance the state-of-the-art composite non-absorbable sutures and contribute to a better understanding of the hybridization concept for optimizing composite material systems.

Mechanical properties of a biodegradable self-expandable polydioxanone monofilament stent: In vitro force relaxation and its clinical relevance

Biodegradable stents are promising treatments for many diseases, e.g., coronary artery disease, urethral diseases, tracheal diseases, and esophageal strictures. The mechanical properties of biodegradable stent materials play a key role in the safety and efficacy of treatment. In particular, insufficient creep resistance of the stent material could result in premature stent collapse or narrowing. Commercially available biodegradable self-expandable SX-ELLA stents made of polydioxanone monofilament were tested. A new, simple, and affordable method to measure the shear modulus of tiny viscoelastic wires is presented. The important mechanical parameters of the polydioxanone filament were obtained: the median Young's modulus was [Formula: see text] = 958 (922, 974) MPa and the shear modulus was [Formula: see text] = 357 (185, 387) MPa, resulting in a Poisson's ratio of ν = 0.34. The SX-ELLA stents exhibited significant force relaxation due to the stress relaxation of the polydioxanone monofilament, approximately 19% and 36% 10 min and 48 h after stent application, respectively. However, these results were expected, and the manufacturer and implanting clinician should be aware of the known behavior of these biodegradable materials. If possible, a biodegradable stent should be designed considering therapeutic force rather than initial force. Additionally, new and more advanced biodegradable shape-memory polymers should be considered for future study and use.

Tensile properties of synthetic, absorbable monofilament suture materials before and after incubation in phosphate-buffered saline

OBJECTIVE

To compare tensile properties of synthetic, absorbable, monofilament suture material before and after incubation in phosphate-buffered saline (PBS).

STUDY DESIGN

Two sizes (2-0 and 3-0) of Biosyn, Maxon, Monocryl, PDS II, Securocryl, and Securodox were tested.

SAMPLE POPULATION

Ten suture loops per group.

METHODS

Tensile strength, elongation, and modulus of suture loops were measured at baseline and after 7, 14, 21, or 28 days of incubation in PBS.

RESULTS

Size, suture material, and size × suture material interaction influenced maximum breaking load, maximum elongation, and modulus of elasticity. At baseline, 2-0 and 3-0 Maxon had the highest breaking loads (111.67 N and 79.71 N, respectively) for their size, and 2-0 PDSII and 3-0 Securodox had the lowest (68.71 N and 48.73 N, respectively). Maxon 2-0 and 3-0 had the greatest elongations (9.68 mm and 8.45 mm, respectively) for their size, and 2-0 Biosyn and 3-0 Securocryl had the least (7.21 mm and 6.58 mm, respectively). Biosyn 2-0 and 3-0 had the highest modulus. With incubation, Maxon (2-0), PDS II (2-0, 3-0), and Securodox (2-0, 3-0) maintained or gained strength over 4 weeks. Strengths of 2-0 and 3-0 Biosyn and 3-0 Maxon were maintained for 2 weeks, while Monocryl and Securocryl lost 20% to 44% of baseline strength within 1 week and 60% to 72% within 2 weeks. Day 7 strengths of 2-0 Biosyn and 2-0 Monocryl were greater than baseline strength of 2-0 PDS II. Strength of 3-0 Biosyn at day 14 was greater than strength of Monocryl at days 7 and 14 and greater than strength of 3-0 PDS II, 3-0 Securodox, and 3-0 Securocryl at baseline and days 7 and 14.

CONCLUSION

Suture tensile properties varied with suture size, composition, and brand. At baseline, Maxon suture had the greatest strength and elongation, and Biosyn had the greatest stiffness.

CLINICAL SIGNIFICANCE

Tensile strength retention, when reported as a percentage of original strength, provides insufficient information for comparison of suture tensile properties.

Preference of Suture Specifications in a Selected Periodontal and Implant Surgeries in Turkey

Objective Various suture materials and needles are now available for use in the dental surgery. The aim of this study was to determine the preference of suture materials among Turkish dentists by a dental survey.

Materials and Methods The survey was prepared and sent electronically to Turkish dentists through e-mail and/or Facebook. Dentists were asked to report their graduation year from dental school and their specialty if they have one. In addition, the type periodontal/implant operations and the frequency of those operations applied by them were questioned. The participants were to indicate their suture preferences for these procedures in a multiple-choice questionnaire.

Results Fifty-seven regular dentists, 49 periodontists, 22 oral surgeons, and 8 other specialists completed a self-administered survey. The majority of clinicians worked in private practice (77.9%). Nonabsorbable sutures were the most preferred for all procedures except periodontal plastic surgery. In regenerative surgeries, monofilament, 5–0 diameter suture material on a reverse cutting, 3/8 circle needle was preferred. In addition, for mucogingival surgery, 5–0 diameter suture material on a reverse cutting and 3/8 circle needle was favored. For dental implants, 4–0 diameter suture material on a reverse cutting and 3/8 circle needle was preferred. Monofilament and braided sutures were selected almost equally for implant operations.

Conclusions In periodontal and implant surgeries, dentists highly preferred the use of nonabsorbable sutures. In addition, the shape and diameter of needle had an important role in the selection of suture material. The present study's results may serve as a guide for the future studies.

Four-Dimensional Imaging of Soft Tissue and Implanted Biomaterial Mechanics: A Barbed Suture Case Study for Tendon Repair

Timely, recent developments in X-ray microcomputed tomography (XμCT) imaging such as increased resolution and improved sample preparation enable nondestructive time-lapse imaging of polymeric biomaterials when implanted in soft tissue, which we demonstrate herein. Imaging the full three-dimensional (3D) structure of an implanted biomaterial provides new opportunities to assess the micromechanics of the interface between the implant and tissues and how this changes over time as force is applied in load-bearing musculoskeletal applications. In this paper, we present a case study demonstrating in situ XμCT and finite element analysis, using a dynamically loaded barbed suture repair for its novel use in tendon tissue. The aim of this study was to identify the distribution of stress in the suture and tendon as load is applied. The data gained demonstrate a clear 3D visualization of microscale features in both the tissue and implant in wet conditions. XμCT imaging has revealed, for the first time, pores around the suture, preventing full engagement of all the barbs with the tendon tissue. Subsequent finite element analysis reveals the localized stress and strain, which are not evenly distributed along the suture, or throughout the tissue. This case study demonstrates for the first time a powerful in situ mechanical imaging tool, which could be readily adapted by other laboratories to interrogate and optimize the interface between the implanted biomaterials and the soft tissue.

Biomechanical Modeling of Prosthetic Mesh and Human Tissue Surrogate Interaction

Surgical repair of hernia and prolapse with prosthetic meshes are well-known to cause pain, infection, hernia recurrence, and mesh contraction and failures. In literature, mesh failure mechanics have been studied with uniaxial, biaxial, and cyclic load testing of dry and wet meshes. Also, extensive experimental studies have been conducted on surrogates, such as non-human primates and rodents, to understand the effect of mesh stiffness, pore size, and knitting patterns on mesh biocompatibility. However, the mechanical properties of such animal tissue surrogates are widely different from human tissues. Therefore, to date, mechanics of the interaction between mesh and human tissues is poorly understood. This work addresses this gap in literature by experimentally and computationally modeling the biomechanical behavior of mesh, sutured to human tissue phantom under tension. A commercially available mesh (Prolene®) was sutured to vaginal tissue phantom material and tested at different uniaxial strains and strain rates. Global and local stresses at the tissue phantom, suture, and mesh were analyzed. The results of this study provide important insights into the mechanics of prosthetic mesh failure and will be indispensable for better mesh design in the future.

An Evidence-Based Rapid Review of Surgical Techniques for Correction of Prolapsed Nictitans Glands in Dogs

Prolapsed nictitans gland (PNG) is an important ocular condition of dogs. Various surgical interventions have been described, but effective technique is currently considered to be a matter of personal clinician preference. The aim of this rapid review was to evaluate existing peer-reviewed evidence of effectiveness for surgical techniques and their subsequent effects on quantitative and clinical lacrimal outcomes for PNG. We performed a structured bibliographic search of CAB Abstracts, PubMed, and Medline using terms relevant to dogs, nictitans gland, and surgery on 13 September 2017. Included studies were assessed for study design, reporting characteristics, surgical techniques, and surgical and lacrimal outcomes. Fifteen of three hundred fifteen identified studies were eligible for inclusion. Seven different replacement techniques were identified, along with gland excision. All studies were observational or descriptive, with the exception of a single crossover trial. Outcomes reporting was heterogeneous and provided limited detail on lacrimal outcomes or on breed propensity for recurrence. Insufficient data precluded comparison of techniques for either surgical failure rates or lacrimal outcomes, although proportional meta-analysis yielded an overall failure rate of 3% (95% CI 1–7%) for the Morgan’s pocket procedure. Improved reporting of veterinary surgical studies will improve evidence appraisal and synthesis, as well as reduce potential sources of bias.

A combined approach for the development of novel sutures with antibacterial and regenerative properties: the role of silver and silk sericin functionalization

Chronic wounds and related infections cause physical and psychological distress in patients, increased mortality, disability and high health care costs. The healing process can be delayed by several factors and in particular by the risk of infections, which can be further complicated by the increasing number of antibiotic-resistant microorganisms. New approaches in wounds management have been encouraged, aiming at preventing infections and improving wound healing. In this scenario, silver has emerged as an ideal antimicrobial agent due to its recognized efficacy against bacteria, viruses and fungi. Moreover, silk and in particular silk sericin from Bombyx mori has demonstrated excellent biological properties and can be considered a good candidate for skin tissue engineering. In this study absorbable PLGA sutures were functionalized with silk sericin and, then, they were treated with silver through an in situ photochemical deposition technology in order to develop an antibacterial and regenerative biomedical device. Morphological analysis was performed by Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy (SEM-EDX) in order to evaluate the presence and distribution of silver deposited on the sutures. The stability and durability of the sericin/silver coatings were tested and the results were related to both antibacterial properties and sample degradation. The biological analyses also aimed at studying the biocompatibility and wound healing properties of the device, evaluating the synergistic effect between sericin and silver.

The Effect of Suture Materials on the Biomechanical Performance of Different Flexor Tendon Repairs and the Concept of Construct Efficiency

BACKGROUND

To propose a new term ('construct efficiency') for the evaluation of multi strands flexor tendon repairs using different suture materials.

METHODS

A total of twenty specimens from 4-0 braided polyblend sutures (FiberLoop/FiberWire; Arthrex, Naples, FL) and 4-0 nylon sutures (Supramid Extra II; S. Jackson, Inc., Alexandria, VA) were subjected to tensile testing using Pneumatic Cord-and-Yarn Grips (Instron Corp., Canton MA, USA). The ultimate tensile strengths of the suture materials were measured. The expected repair strengths and construct efficiencies were computed based on the experimental results and from available literature on actual repair strengths of the 4-strand Becker, Cruciate repairs and 6-strand Tang, modified Lim-Tsai repairs.

RESULTS

The ultimate tensile strength of nylon suture was 15.4 ± 0.6N, lower than that of braided polyblend suture (45.3 ± 2.3N) with a difference of 194%. The construct efficiency of multi strand repairs varied with respect to different repair techniques and suture materials. It was found that the Becker repairs using FiberWire had the highest construct efficiency (55.7%) followed by the modified Lim-Tsai using Supramid (50.9%), Tang repair using Supramid (49.8%), Cruciate repair using Fiberwire (49.1%), and modified Lim-Tsai repair using FiberLoop (33.5%).

CONCLUSIONS

The construct efficiency is more accurate in showing that, in terms of biomechanical strength, the use of FiberWire for the 4-strand Becker and Cruciate repair is more efficient than that of using FiberLoop for 6-strand modified Lim-Tsai repair.

Arthroscopic suture bridge fixation technique with multiple crossover ties for posterior cruciate ligament tibial avulsion fracture

PURPOSE

This study examined the clinical outcomes of a newly developed technique, arthroscopic suture bridge fixation with crossover ties of PCL tibial avulsion fracture using two tibial tunnels and a posterior trans-septal portal.

METHODS

Records were reviewed of 18 patients (median age 33.5 years, range 13-55 years) with PCL tibial avulsion fractures treated with an arthroscopic suture bridge technique. Knee function before surgery and at last follow-up was evaluated by Lysholm and Tegner scores. A KT-2000 arthrometer was used to evaluate knee stability, and fracture union was assessed by plain radiographs.

RESULTS

Mean postoperative Lysholm (P < 0.001) and Tegner (P = 0.011) scores showed significant improvements compared with preoperative scores. Arthrometry showed that the mean side-to-side difference improved significantly, from 7.8 ± 0.8 mm preoperatively to 3 ± 1.2 mm postoperatively (P = 0.012). Radiographic evaluation showed solid union at the fracture site in all 18 patients at last follow-up.

CONCLUSION

This new arthroscopic double-tunnel pull-out suture bridge fixation with multiple crossover ties and posterior trans-septal technique for PCL tibial avulsion fracture yielded good clinico-radiological outcomes, including satisfactory stability and fracture site healing. This technique can be a useful treatment option for PCL tibial avulsion fracture even with small comminuted fracture due to compression by the unique crossover configuration mesh of multiple fixation sutures.

LEVEL OF EVIDENCE

IV.

Polyester Preserves the Highest Breaking Point After Prolonged Incubation in Pancreatic Juice

BACKGROUND

The impact of suture materials on the development of pancreatic fistula after pancreaticoduodenectomy remains unclear. Thus, their choice among pancreatic surgeons is still mostly experience-based. Aim of the present study is to assess what is the best suture material to be used for pancreaticojejunostomy.

MATERIALS AND METHODS

The force needed to reach the breaking point of five widely used suture materials (polypropylene, polyester, polydioxanone, silk, and polyglactin 910) has been determined through a digital precision dynamometer at baseline and after 5 and 20 days of incubation in pancreatic juice, bile, or a mixture of both.

RESULTS

Regardless of the condition, polyglactin 910 has retained only 10% of its baseline force. Silk has maintained almost 90% of its initial force showing a very low baseline value of force. In pancreatic juice, polypropylene has lost less force compared to polyester (0.25 vs. 0.93 N; p = 0.03) and polydioxanone (0.25 vs. 3.67 N; p = 0.04). Polyester and polydioxanone have showed similar values of force. However, polydioxanone has lost a significant amount of force in pancreatic juice when compared to polyester (0.93 vs. 3.67 N; p = 0.03). Polyester has showed the highest value of force needed to reach the breaking point after 20 days of incubation in pancreatic juice.

CONCLUSIONS

After incubation in pancreaticobiliary secretions, polyglactin 910 loses almost all its force. Polypropylene preserves its characteristic, but polydioxanone and polyester show absolute higher breaking points, with polyester retaining the highest value of force needed to reach its breaking point after incubation in pancreatic juice.

A Growth-Accommodating Implant for Paediatric Applications

Medical implants of fixed size cannot accommodate normal tissue growth in children, and often require eventual replacement or in some cases removal, leading to repeated interventions, increased complication rates and worse outcomes. Implants that can correct anatomic deformities and accommodate tissue growth remain an unmet need. Here, we report the design and use of a growth-accommodating device for paediatric applications that consists of a biodegradable core and a tubular braided sleeve, with inversely related sleeve length and diameter. The biodegradable core constrains the diameter of the sleeve, and gradual core degradation following implantation enables sleeve and overall device elongation in order to accommodate tissue growth. By using mathematical modeling and ex vivo experiments using harvested swine hearts, we demonstrate the predictability and tunability of the behavior of the device for disease- and patient-specific needs. We also used the rat tibia and the piglet heart valve as two models of tissue growth to demonstrate that polymer degradation enables device expansion and growth accommodation in vivo.

Tension Regulation at the Suture Lines for Repair of Neglected Achilles Tendon Laceration

BACKGROUND

Operative intervention is the preferred option for management of the neglected laceration of the Achilles tendon. However, the commonly used techniques rarely follow the principles of the regenerative medicine for the restoration of the lost tissue. This study postulated that incorporation of the autogenous tendon graft would properly progress when the interplay between mechanical loading and healing phases was correctly applied.

METHODS

A prospective study included 15 patients who were treated for neglected Achilles tendon laceration using the technique of lengthening of the proximal tendon stump. An absorbable reinforcement suture was used for control of the mechanical environment at the suture lines.

RESULTS

By an average 5 years of the prospective follow-up, all the repaired tendons had restored continuity and length. The calf circumference equalized to the uninjured side in 12 patients. However, 3 patients had calf atrophy but they improved compared to the preoperative measurements. Sonogram confirmed the restoration of the normal thickness and the gliding characteristics of the repaired tendon.

CONCLUSION

The technique restored continuity and tension of the repaired tendon, preserved the calf circumference, and prevented peritendinous adhesions. The absorbable reinforcement suture spontaneously allowed for the mechanical loading of the grafted tendon.

LEVEL OF EVIDENCE

Level IV, case series.

A REALISTIC 3D COMPUTATIONAL MODEL OF THE CLOSURE OF SKIN WOUND WITH INTERRUPTED SUTURES

Wounds or cuts are the most common form of skin injuries. While a shallow wound may heal over time, deep wounds often require clinical interventions such as suturing to ensure the wound closure and timely healing. To date, suturing practices are based on a surgeon's experience and there is no benchmark to what is right or wrong. In the literature, there have been few attempts to characterize wound closure and suture mechanics using simple 2D computational models. In our current work, for the first time, a realistic three-dimensional (3D) computational model of the skin with the two layers, namely the epidermis and dermis, have been developed. A 3D diamond shaped wound with a varying cross-section has been modeled, and interrupted sutures have been placed numerically in multiple steps to close the wound. Nonlinear hyperelastic material properties have been adopted for the skin and a skin pre-stress was applied bi-axially. The force requirements for each suture were estimated numerically using a novel suture pulling technique. The suture forces were found to lie in the range of 0–5 N with a maximum value at the center. Also, the center suture was observed to require an approximately four times pull force compared to the first end suture. All these findings provide important guidelines for suturing. Additionally, the suture force can be approximated as a polynomial function of the displacement. Given a wound geometry, wound depth, skin material properties, skin pre-stress, suture wire material and cross-sectional area, using our computational model, such a relationship can be used to estimate and characterize the suture force requirements accurately. To our knowledge, such a 3D computational model of skin wound closure with interrupted sutures have not been developed till date, and would be indispensable for planning robotic surgeries and improving clinical suturing practices in the future.

Experimental study on tissue phantoms to understand the effect of injury and suturing on human skin mechanical properties

Skin injuries are the most common type of injuries occurring in day-to-day life. A skin injury usually manifests itself in the form of a wound or a cut. While a shallow wound may heal by itself within a short time, deep wounds require surgical interventions such as suturing for timely healing. To date, suturing practices are based on a surgeon's experience and may vary widely from one situation to another. Understanding the mechanics of wound closure and suturing of the skin is crucial to improve clinical suturing practices and also to plan automated robotic surgeries. In the literature, phenomenological two-dimensional computational skin models have been developed to study the mechanics of wound closure. Additionally, the effect of skin pre-stress (due to the natural tension of the skin) on wound closure mechanics has been studied. However, in most of these analyses, idealistic two-dimensional skin geometries, materials and loads have been assumed, which are far from reality, and would clearly generate inaccurate quantitative results. In this work, for the first time, a biofidelic human skin tissue phantom was developed using a two-part silicone material. A wound was created on the phantom material and sutures were placed to close the wound. Uniaxial mechanical tests were carried out on the phantom specimens to study the effect of varying wound size, quantity, suture and pre-stress on the mechanical behavior of human skin. Also, the average mechanical behavior of the human skin surrogate was characterized using hyperelastic material models, in the presence of a wound and sutures. To date, such a robust experimental study on the effect of injury and sutures on human skin mechanics has not been attempted. The results of this novel investigation will provide important guidelines for surgical planning and validation of results from computational models in the future.

Two-month longitudinal study of mechanical properties of absorbable sutures used in orthopedic surgery

Background

This is the first study assessing the properties of large-diameter degradable sutures relevant for orthopedic applications over the course of in vitro incubation for 2 months. The data we present here provide guidance to the orthopedic surgeon in predicting the long-term performance of suture materials used everyday in surgical practice.

Methods

Five different absorbable (Vicryl, Maxon, Monocryl, PDS II, Vicryl rapide) and one non-absorbable (Ethibond) suture materials were tested. Measurements were made at five time points during the 56 days of incubation under physiological conditions (37.0 ± 0.02 °C; pH 7.4 ± 0.2). The following variables were recorded: load to failure, strain at maximal load as elongation normalized to original length, stiffness as the ratio of load to displacement on the linear proportion of the stress strain curve, and hysteresis as area under the curve of the stress strain curve.

Results

Vicryl was the strongest fiber on day 0 (195 N); however, by day 42, the tensile strength of the suture reduced to 14 N. Between days 14 and 28, PDS II (171 N) and Maxon (182 N) sustained the highest loads. Monocryl (p = 0.003) and Maxon (p < 0.001) showed an increasing strain with time, whereas Vicryl (p = 0.002) and Vicryl rapide (p = 0.007) revealed an increasing material stiffness. Furthermore, both Vicryl (p = 0.053) and Monocryl (p < 0.001) had an increasing hysteresis with ongoing degradation. Maxon, PDS II, and Ethibond showed stable material properties during the 2 months.

Conclusions

The three absorbable sutures Vicryl, PDS II, and Maxon could sustain higher loads during the first 2 weeks than the non-absorbable Ethibond. Unexpectedly, Maxon and PDS II maintained their elastic properties in spite of their proceeding degradation and loss of tensile strength.

Co-effect of silk and amniotic membrane for tendon repair

The objective of the present study was to determine the feasibility and biocompatibility of a silk scaffold and a composite silk scaffold in terms of new tendon generation using a rabbit Achilles tendon model. The silk scaffold was constructed using a weaving machine, then soaked in a 1% collagen-hyaluronan (HA) solution and air-dried, whereas the composite silk scaffold was composed of a silk scaffold containing a lyophilized collagen-HA substrate. Tenocytes were cultured in vitro to compare cell populations in the two groups. The cellular densities on composite silk scaffolds were 40% higher on average than those on silk scaffolds in 30-day tenocyte cultures. The tendon scaffolds had implanted into Achilles tendon defects in 16 white New Zealand rabbits. Rabbits were randomly divided into the following three groups: group I, silk scaffold alone; group II, composite silk scaffold; and group III, composite silk scaffold wrapped by an amniotic membrane. Implants were harvested 2, 8, and 12 weeks post-implantation. Histological examinations were conducted using hematoxylin-eosin (H&E), Masson's trichrome, and by performing immunohistochemical staining for CD34. After 12 weeks, the three groups were distinguishable based on gross examination. The histological examination revealed more organized collagen fibrils in groups III, which showed a dense, parallel, linear organization of collagen bundles. CD34 staining revealed neoangiogenesis in groups III. The results of this research showed that collagen-HA substrates with amniotic membrane accelerate cellular migration and angiogenesis in neotendons.

Fabrication of silk mesh with enhanced cytocompatibility: preliminary in vitro investigation toward cell-based therapy for hernia repair

Recent studies have demonstrated that combining cells with meshes prior to implantation successfully enhanced hernia repair. The idea is to create a biologic coating surrounding the mesh with autologous cells, before transplantation into the patient. However, due to the lack of a prompt and robust cell adhesion to the meshes, extensive in vitro cultivation is required to obtain a homogenous cell layer covering the mesh. In this context, the objective of this publication is to manufacture meshes made of silk fibres and to enhance the cytoadhesion and cytocompatibility of the biomaterial by surface immobilization of a pro-adhesive wheat germ agglutinin (lectin WGA). We first investigated the affinity between the glycoprotein WGA and cells, in solution and then after covalent immobilization of WGA on silk films. Then, we manufactured meshes made of silk fibres, tailored them with WGA grafting and finally evaluated the cytocompatibility and the inflammatory response of silk and silk-lectin meshes compared to common polypropylene mesh, using fibroblasts and peripheral blood mononuclear cells, respectively. The in vitro experiments revealed that the cytocompatibility of silk can be enhanced by surface immobilization with lectin WGA without exhibiting negative response in terms of pro-inflammatory reaction. Grafting lectin to silk meshes could bring advantages to facilitate cell-coating of meshes prior to implantation, which is an imperative prerequisite for abdominal wall tissue regeneration using cell-based therapy.

Polycarbonate-based biodegradable copolymers for stimuli responsive targeted drug delivery

The newly developed polymeric nanocarrier could open a new avenue for cancer therapy, due to its unique design as well as, most importantly, its biocompatible and biodegradable nature.

Pancreaticojejunostomy after pancreaticoduodenectomy: Suture material and incidence of post-operative pancreatic fistula

PURPOSE

Pancreatic fistula represents the most important complication in terms of clinical management and costs after pancreaticoduodenectomy. A lot of studies have investigated several techniques in order to reduce pancreatic fistula, but data on the effect of sutures material on pancreatic fistula are not available. The analysis investigated the role of suture material in influencing pancreatic fistula rate and severity.

METHODS

Results from 130 consecutive pancreaticoduodenectomy with pancreaticojejunostomy performed between March 2013 and September 2014 were prospectively collected and analyzed. In 65 cases pancreaticojejunostomy was performed with absorbable sutures, in the other 65 cases using non-absorbable sutures (polyester, silk and polybutester).

RESULTS

Pancreaticojejunostomy with non-absorbable sutures had the same incidence of pancreatic fistula, but less severe and with less episodes of post-operative bleeding if compared with absorbable sutures. A sub-analysis was carried out comparing polydioxanone with polyester: the latter was associated with a lower pancreatic fistula rate (11.9% vs. 31.7%; p = 0,01) and less severe pancreatic anastomosis dehiscence (grade C - 0% vs. 30%; p = 0.05). Univariate and multivariate analysis confirmed that hard pancreatic texture, pancreatic ductal adenocarcinoma at final histology and the use of polyester for pancreaticojejunostomy were associated with a lower pancreatic fistula rate (p < 0.05).

CONCLUSION

Further studies are needed to investigate the effects of pancreatic juice and bile on different sutures and pancreatic tissue response to different materials. However, pancreaticojejunostomy performed with polyester sutures is safe and feasible and is associated to a lower incidence of pancreatic fistula with less severe clinical impact.