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

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.

Recent advances in biodegradable metals for medical sutures: a critical review

Sutures that biodegrade and dissolve over a period of several weeks are in great demand to stitch wounds and surgical incisions. These new materials are receiving increased acceptance across surgical procedures whenever permanent sutures and long-term care are not needed. Unfortunately, both inflammatory responses and adverse local tissue reactions in the close-to-stitching environment are often reported for biodegradable polymeric sutures currently used by the medical community. While bioabsorbable metals are predominantly investigated and tested for vascular stent or osteosynthesis applications, they also appear to possess adequate bio-compatibility, mechanical properties, and corrosion stability to replace biodegradable polymeric sutures. In this Review, biodegradable alloys made of iron, magnesium, and zinc are critically evaluated as potential materials for the manufacturing of soft and hard tissue sutures. In the case of soft tissue closing and stitching, these metals have to compete against currently available degradable polymers. In the case of hard tissue closing and stitching, biodegradable sternal wires could replace the permanent sutures made of stainless steel or titanium alloys. This Review discusses the specific materials and degradation properties required by all suture materials, summarizes current suture testing protocols and provides a well-grounded direction for the potential future development of biodegradable metal based sutures.

Arthroscopic fixation of an avulsion fracture of the tibia involving the posterior cruciate ligament

A total of 22 patients with a tibial avulsion fracture involving the insertion of the posterior cruciate ligament (PCL) with grade II or III posterior laxity were reduced and fixed arthroscopically using routine anterior and double posteromedial portals. A double-strand Ethibond suture was inserted into the joint and wrapped around the PCL from anterior to posterior to secure the ligament above the avulsed bony fragment. Two tibial bone tunnels were created using the PCL reconstruction guide, aiming at the medial and lateral borders of the tibial bed. The ends of the suture were pulled out through the bone tunnels and tied over the tibial cortex between the openings of the tunnels to reduce and secure the bony fragment. Satisfactory reduction of the fracture was checked arthroscopically and radiographically.

The patients were followed-up for a mean of 24.5 months (19 to 28). Bone union occurred six weeks post-operatively. At final follow-up, all patients had a negative posterior drawer test and a full range of movement. KT-1000 arthrometer examination showed that the mean post-operative side-to-side difference improved from 10.9 mm (standard deviation (sd) 0.7) pre-operatively to 1.5 mm (sd 0.6) (p = 0.001). The mean Tegner and the International Knee Documentation Committee scores improved significantly (p = 0.001). The mean Lysholm score at final follow-up was 92.0 (85 to 96).

We conclude that this technique is convenient, reliable and minimally invasive and successfully restores the stability and function of the knee.

Cite this article: Bone Joint J 2015;97-B:1220–5.

The appropriate use of neurostimulation: avoidance and treatment of complications of neurostimulation therapies for the treatment of chronic pain. Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The International Neuromodulation Society (INS) has determined that there is a need for guidance regarding safety and risk reduction for implantable neurostimulation devices. The INS convened an international committee of experts in the field to explore the evidence and clinical experience regarding safety, risks, and steps to risk reduction to improve outcomes.

METHODS

The Neuromodulation Appropriateness Consensus Committee (NACC) reviewed the world literature in English by searching MEDLINE, PubMed, and Google Scholar to evaluate the evidence for ways to reduce risks of neurostimulation therapies. This evidence, obtained from the relevant literature, and clinical experience obtained from the convened consensus panel were used to make final recommendations on improving safety and reducing risks.

RESULTS

The NACC determined that the ability to reduce risk associated with the use of neurostimulation devices is a valuable goal and possible with best practice. The NACC has recommended several practice modifications that will lead to improved care. The NACC also sets out the minimum training standards necessary to become an implanting physician.

CONCLUSIONS

The NACC has identified the possibility of improving patient care and safety through practice modification. We recommend that all implanting physicians review this guidance and consider adapting their practice accordingly.

Anterior cruciate ligament reconstruction in a rabbit model using silk-collagen scaffold and comparison with autograft

The objective of the present study was to perform an in vivo assessment of a novel silk-collagen scaffold for anterior cruciate ligament (ACL) reconstruction. First, a silk-collagen scaffold was fabricated by combining sericin-extracted knitted silk fibroin mesh and type I collagen to mimic the components of the ligament. Scaffolds were electron-beam sterilized and rolled up to replace the ACL in 20 rabbits in the scaffold group, and autologous semitendinosus tendons were used to reconstruct the ACL in the autograft control group. At 4 and 16 weeks after surgery, grafts were retrieved and analyzed for neoligament regeneration and tendon-bone healing. To evaluate neoligament regeneration, H&E and immunohistochemical staining was performed, and to assess tendon-bone healing, micro-CT, biomechanical test, H&E and Russell-Movat pentachrome staining were performed. Cell infiltration increased over time in the scaffold group, and abundant fibroblast-like cells were found in the core of the scaffold graft at 16 weeks postoperatively. Tenascin-C was strongly positive in newly regenerated tissue at 4 and 16 weeks postoperatively in the scaffold group, similar to observations in the autograft group. Compared with the autograft group, tendon-bone healing was better in the scaffold group with trabecular bone growth into the scaffold. The results indicate that the silk-collagen scaffold has considerable potential for clinical application.

Geometrically controlled tensile response of braided sutures

Sutures are the materials used for wound closure that are caused by surgery or trauma. The main pre-requisite to the success of the suture is to obtain ultimate level of tensile properties with defined geometrical constraints. In this communication, the model for tensile properties of braided sutures has been proposed by elucidating the most important geometrical and material parameters. The model has accounted for the kinematical changes occurring in the braid and constituent strand geometries under defined level of strain. A comparison has been made between the theoretical and experimental results of stress-strain characteristics of braided sutures.

Management of comminuted patellar fracture with non-absorbable suture cerclage and Nitinol patellar concentrator

PURPOSE

To evaluate the effectiveness and safety of a fixation technique for comminuted patellar fracture using non-absorbable suture cerclage and nickel-titanium patellar concentrator (Ni-Ti PC).

METHODS

Twenty-nine consecutive patients with displaced comminuted patellar fractures accepted internal fixation procedure using Ni-Ti PC augmented with different types of non-absorbable suture cerclage. During follow-up, the clinical grading scales of Böstman, including range of movement, pain, work, atrophy, assistance in walking, effusion, giving way, and stair-climbing, were used to evaluate the clinical results. Complications including implant loosening, fragment displacement, bone nonunion, infection, breakage of the implants, painful hardware, and post-traumatic osteoarthritis were also assessed.

RESULTS

Patients were followed up for a mean period of 27 months. The bone union radiographically occurred approximately 2.5 months without implant loosening and fragment displacement. According to Böstman method, satisfactory results were obtained, and the mean score at final follow-up was 28 (range 20–30) points. Twenty-two patients with excellent results had mean score of 29.8 ± 0.5 (range 28–30) and seven patients with good results had mean score of 22.7 ± 3.14 (range 20–27). No postoperative complications, such as infection, dislocation, breakage of the implants, painful hardware, and post-traumatic osteoarthritis, were observed.

CONCLUSION

Ni-Ti PC fixation with non-absorbable suture cerclage is a feasible approach for comminuted patellar fractures. Firm fixation with this technique resulted in satisfactory outcomes without obvious complications.

Rapid prototyped sutureless anastomosis device from self-curing silk bio-ink

Sutureless anastomosis devices are designed to reduce surgical time and difficulty, which may lead to quicker and less invasive cardiovascular anastomosis. The implant uses a barb-and-seat compression fitting composed of one male and two female components. The implant body is resorbable and capable of eluting heparin. Custom robotic deposition equipment was designed to fabricate the implants from a self-curing silk solution. Curing did not require deleterious processing steps but devices demonstrated high crush resistance, retention strength, and leak resistance. Radial crush resistance is in the range of metal vascular implants. Insertion force and retention strength of the anastomosis was dependent on fit sizing of the male and female components and subsequent vessel wall compression. Anastomotic burst strength was dependent on the amount of vessel wall compression, and capable of maintaining higher than physiological pressures. In initial screening using a porcine implant, the devices remained intact for 28 days (the length of study). Histological sections revealed cellular infiltration within the laminar structure of the male component, as well as at the interface between the male and female components. Initial degradation and absorption of the implant wall were observed. The speed per anastomosis using this new device was much faster than current systems, providing significant clinical improvement.

Development of silver nano-coatings on silk sutures as a novel approach against surgical infections

The infections give rise to a range of clinical problems and prolong hospitalization with increased healthcare costs. Moreover, persistent infections exasperate the problem of antibiotic resistance. The aim of this study was the development of effective and low-cost antibacterial silver coatings on surgical sutures by adopting an innovative photochemical deposition process to prevent early contamination of surgical wounds. The silver deposition technology adopted in this work is an innovative process based on the in situ photoreduction of a silver solution. The samples were dipped in the silver solution and then exposed to UV radiation in order to induce the synthesis of silver clusters on the surface of the suture. The homogeneous distribution of silver particles on the surface and on the cross-section of the treated sutures was demonstrated. All the antibacterial studies clearly demonstrated that the use of novel silver treated sutures could represent clinical advantages in terms of the prevention of surgical infections against bacterial colonization. The silver coating deposited on the sutures demonstrated no cytotoxic effect on a selected cell population. The results obtained suggested that the antibacterial silver-coated sutures developed in this work could represent an interesting alternative to conventional sutures, with evident advantages in terms of prevention of the surgical infections and on the health costs. In addiction, very low concentrations of silver significantly inhibited the microbial load, without affecting the cell viability.

Evaluation of five different suture materials in the skin of the earthworm (Lumbricus terrestris)

The purpose of this study was to determine which suture material is the most appropriate for dermal closure of terrestrial annelids. This paper describes the tissue reactions of the earthworm, Lumbricus terrestris, to five different types of suture materials in order to determine which suture material is the most appropriate for dermal closure. Silk, monofilament nylon, polydiaxonone, polyglactin 910, and chromic gut were studied. There was mild to moderate tissue reaction to all five suture materials. In all of the biopsies wound-healing reaction consisted of aggregates of blastemal cells which appeared in various stages of dedifferentiation from the body wall. Inflammatory cells infiltrated the wound sites, reminiscent of the typical foreign body reaction in vertebrates. The results indicate polyglactin 910 would be the best suture material with regards to tissue security and reaction scores. Chromic gut occupies the next position but there were problems with suture security over time. This appears to be the first suture material performance study on a terrestrial invertebrate. The earthworm, Lumbricus terrestris, was chosen for its wide availability, size, and the extensive species knowledge base. The earthworm may prove to be a good surgical/suture model for economically important invertebrates such as mollusks, tunicates, and insect larval stages.

Flexor Tendon Injuries in the Hand: A UK Survey of Repair Techniques and Suture Materials—Are We Following the Evidence?

Introduction. Injuries to the hand are common, and poor functional outcomes can have significant long-term consequences affecting both work and social activities. Good outcomes following flexor tendon lacerations in the hand are dependent on a sound surgical repair allowing early active mobilisation. Materials and Methods. We reviewed the literature regarding the choice of suture material and repair technique. We then carried out a nationwide postal survey of plastic surgery hand units to assess the level of compliance with the evidence. Results. Fifty-four units were surveyed. The response rate was 72%, with the most popular core suture being Prolene (64%) and the most popular technique being the Kessler repair (36%). Discussion. Current evidence advocates a multistrand repair using Ethibond. We found that the majority of units are not following the evidence. We suggest the use of evidence-based departmental guidelines to improve the practice and outcomes following these common injuries.

Biocompatibility and adhesion formation of different endoloop ligatures in securing the base of the appendix

BACKGROUND AND OBJECTIVES

The common technique used in securing the base of the appendix is Endoloop ligature (Ethicon, Somerville, NJ, USA). Vicryl (polyglactin 910) (Ethicon) and polydioxanone (PDS) (Ethicon) Endoloop ligatures can be used. There are potential benefits of the use of PDS Plus (Ethicon) Endoloop ligature. However, the use of different materials may vary in terms of inflammation, foreign-body reaction, rate of infection in the surgical area, or rate of adhesion formation. An ideal suture would induce minimal inflammatory response and adhesion formation.

METHODS

Ninety rats were randomized into 3 groups: group I, in which appendectomy was performed with Vicryl ligature; group II, in which appendectomy was performed with PDS ligature; and group III, in which appendectomy was performed with PDS Plus ligature. The animals were killed on the seventh, 28th, and 60th days after surgery. The secured stump was used for histopathologic and immunohistochemistry analysis, as well as evaluation of the formation of adhesions.

RESULTS

Mild and moderate inflammation was more frequent in the PDS and PDS Plus groups than in the Vicryl group on the seventh postoperative day. There were no significant differences in the degree of inflammation on the 28th and 60th postoperative days. The lowest degree of postoperative adhesions was observed in the PDS group.

CONCLUSION

Milder postoperative inflammatory changes and a lower degree of postoperative adhesions were seen in the PDS ligature group, suggesting that this could be the standard Endoloop used to secure the base of the appendix.

Healing of subcutaneous tendons: Influence of the mechanical environment at the suture line on the healing process

Tendon ruptures remain a significant musculoskeletal injury. Despite advances in surgical techniques and procedures, traditional repair techniques maintain a high incidence of rerupture or tendon elongation. Mechanical loading and biochemical signaling both control tissue healing. This has led some researchers to consider using a technique based on tension regulation at the suture line for obtaining good healing. However, it is unknown how they interact and to what extent mechanics control biochemistry. This review will open the way for understanding the interplay between mechanical loading and the process of tendon healing.

In vitro two-dimensional and three-dimensional tenocyte culture for tendon tissue engineering

In order to examine the differentiation potential of the tenocytes expanded in our defined culture medium (reported previously) and the effect of sequential combination of the two culture conditions on human tenocytes, a two-dimensional and three-dimensional experimental approach was used. Human tenocytes were sequentially exposed to 1% fetal bovine serum (FBS) + 50 ng/ml platelet-derived growth factor-BB (PDGFBB ) + 50 ng/ml basic fibroblast growth factor (bFGF) for the first 14 days (expansion phase) followed by a further 14-day culture in the presence of 10 ng/ml transforming growth factor β-3 plus 50 ng/ml insulin-like growth factor 1, but in the absence of serum (differentiation phase). The results showed that by sequential treatment of human tenocytes maintaining a long-term two-dimensional tenocyte culture in vitro for up to 28 days was possible. These findings were further verified using a three-dimensional scaffold (Bombyx silk) whereby the tendon-like constructs formed resembled macroscopically and microscopically the constructs formed in 10% FBS supplemented culture media and the human hamstring tendon. These findings were further substantiated using haematoxylin and eosin staining, scanning electron microscopy and by immunohistochemical detection of type I collagen. In addition, the mechanical properties of the three-dimensional constructs were determined to be significantly superior to that of the natural human hamstring tendon. This is the first report to demonstrate a possible approach in expanding and differentiating human tenocytes for tendon tissue engineering.

Biodegradable particles as vaccine antigen delivery systems for stimulating cellular immune responses

There is a need for both new and improved vaccination formulations for a range of diseases for which current vaccines are either inadequate or non-existent. Biodegradable polymer-based vaccines fulfill many of the desired properties in achieving effective long-term protection in a manner that is safe, economical, and potentially more practicable on a global scale. Here we discuss some of the work performed with micro/nanoparticles made from either synthetic (poly[lactic-co-glycolic acid] [PLGA] and polyanhydrides) or natural (chitosan) biodegradable polymers. Our attention is focused on, but not limited to, the generation of antitumor immunity where we stress the importance of particle size and co-delivery of antigen and adjuvant.

Comparison of a multifilament stainless steel suture with FiberWire for flexor tendon repairs--an in vitro biomechanical study

Our goal was to investigate and compare the mechanical properties of multifilament stainless steel suture (MFSS) and polyethylene multi-filament core FiberWire in flexor tendon repairs. Flexor digitorum profundus tendons were repaired in human cadaver hands with either a 4-strand cruciate cross-lock repair or 6-strand modified Savage repair using 4-0 and 3-0 multifilament stainless steel or FiberWire. The multifilament stainless steel repairs were as strong as those performed with FiberWire in terms of ultimate load and load at 2 mm gap. This study suggests that MFSS provides as strong a repair as FiberWire. The mode of failure of the MFSS occurred by the suture pulling through the tendon, which suggests an advantage in terms of suture strength.

On the mechanics of bacterial biofilms on non-dissolvable surgical sutures: a laser scanning confocal microscopy-based finite element study

Biofilms are bacterial communities encapsulated within a self-secreted extracellular polymeric substance and are responsible for a wide range of chronic medical device related infections. Understanding and addressing the conditions that lead to the attachment and detachment of biofilms from biomedical surfaces (orthopaedic implants, sutures, intravenous catheters, cardio-vascular stents) has the potential to identify areas of the device that might be more prone to infection and predict how and when biofilms might dislodge. In this study, an integrated software methodology was devised to create image-based microscopic finite element models of real biofilm colonies of Staphylococcus aureus attached to a fragment of surgical suture. The goal was to predict how deformation of the suture may lead to the potential detachment of biofilm colonies by solving the equations of continuum mechanics using the finite element method for various loading cases. Tension, torsion and bending of the biomaterial structure were simulated, demonstrating that small strains in the suture can produce surface shear stresses sufficient to trigger the sliding of biofilms over the suture surface. Applications of this technique to other medical devices are discussed.

Arthroscopic suture fixation for avulsion fractures in the tibial attachment of the posterior cruciate ligament

PURPOSE

The purpose of the study was to highlight our surgical technique of arthroscopic suture fixation for acute tibial eminence posterior cruciate ligament (PCL) avulsion fractures, clinical and radiographic outcomes, and complication rates.

METHODS

This prospective study enrolled patients who had undergone arthroscopic reduction and suture fixation by use of 4 No. 5 Ethibond sutures (Ethicon, Somerville, NJ) for image-proven displaced PCL attachment fractures of the tibial eminence with posterior knee instability of grade II or higher. The mean follow-up period was 36 months (range, 24 to 45 months). Follow-up assessment included 3 different functional scores, KT-1000 arthrometry (MEDmetric, San Diego, CA), and radiographic evaluation.

RESULTS

The mean preoperative Lysholm score in the 36 patients was 35 (range, 26 to 55); the mean postoperative Lysholm score was 95 (range, 80 to 100). The mean preinjury and preoperative Tegner scores in the 36 patients were 7.4 ± 1.6 (range, 5 to 9) and 3.2 ± 1.5 (range, 2 to 5), respectively. The mean postoperative Tegner score was 7.0 ± 1.8 (range, 5 to 9). At the final follow-up, the International Knee Documentation Committee scores were observed to be normal (grade A) or nearly normal (grade B) in 33 patients (91.7%) and abnormal (grade C) in 3 patients (8.3%). All 36 fractures achieved union within 3 months. No significant complications such as arthrofibrosis, loss of initial fixation, or wound infection were noted.

CONCLUSIONS

Treatment of tibial PCL avulsion fractures by arthroscopic suture fixation is a successful technique to restore tibial avulsion injuries of the PCL with well-documented radiographic healing, good clinical outcomes, and low complication rates.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Clinical and histological comparison of polyglycolic acid suture with black silk suture after minor oral surgical procedure

Any suture material, absorbable or nonabsorbable, elicits a kind of inflammatory reaction within the tissue. Nonabsorbable black silk suture and absorbable polyglycolic acid suture were compared clinically and histologically on various parameters.

MATERIALS AND METHODS

This study consisted of 50 patients requiring minor surgical procedure, who were referred to the Department of Oral and Maxillofacial Surgery. Patients were selected randomly and sutures were placed in the oral cavity 7 days preoperatively. Polyglycolic acid was placed on one side and black silk suture material on the other. Seven days later, prior to surgical procedure the sutures will be assessed. After the surgical procedure the sutures will be placed postoperatively in the same way for 7 days, after which the sutures will be assessed clinically and histologically.

RESULTS

The results of this study showed that all the sutures were retained in case of polyglycolic acid suture whereas four cases were not retained in case of black silk suture. As far as polyglycolic acid suture is concerned 25 cases were mild, 18 cases moderate and seven cases were severe. Black silk showed 20 mild cases, 21 moderate cases and six severe cases. The histological results showed that 33 cases showed mild, 14 cases moderate and three cases severe in case of polyglycolic acid suture. Whereas in case of black silk suture 41 cases were mild. Seven cases were moderate and two cases were severe. Black silk showed milder response than polyglycolic acid suture histologically.

CONCLUSION

The polyglycolic acid suture was more superior because in all 50 patients the suture was retained. It had less tissue reaction, better handling characteristics and knotting capacity.

How to close a colpotomy? Barbed suture and conventional suture effects on soft tissue: an ex vivo pilot study

OBJECTIVE

To evaluate the effects of different suture materials and techniques on soft tissue in relation to defined tensions and time points.

MATERIALS AND METHODS

Two bovine intestine samples, 4 × 4 cm size and ~3 mm thickness, were adapted with interrupted and continuous techniques using three types of suture materials: Vicryl (polyglactin 910), PDS II (polydioxanone), and V-Loc 180 (knotless, barbed polyglyconate). Four stitches or loops 9 mm apart with three knots, and 10 mm end length were performed by one gynecologist. Forces were applied from 6 newtons (N) to 14 N continuously. Outcome measures included breakage of tissue, tearing of thread, and shortening of the end length of thread. They were evaluated immediately and then at first, third, and fifth minute.

RESULTS

Tissue breakage using No. 3/0 suture materials appears in the applied force from 10 N. polydioxanone causes more tissue tearing than polyglactin 910. The least to withstand tension is knotless polyglyconate. Interrupted stitches hold the sutured sites better than continuous stitches in all groups of threads. Shortening of the knotless polyglyconate end length by half took place with 6 N force.

CONCLUSION

Simulating reparation of colpotomy, the ex vivo study supports that polyglactin 910 appears better in holding soft tissue than polydioxanone and knotless polyglyconate.

Suturing principles for the dentoalveolar surgeon

Dentists should be aware of the characteristics of suture material, and the technique used should provide effectiveness and ease. Dentists who routinely perform dentoalveolar surgery should have at least 1 type of absorbable and 1 type of nonabsorbable suture readily available within their operatory supply. This article focuses on the physical properties of suture materials and their tissue reactivity, and it reviews various suturing techniques used in contemporary dentoalveolar surgery. Familiarity with the concepts presented in this article, and continuous practice of the surgical skills presented, enhances surgical acumen and allows for improved healing, increased postoperative comfort, and successful surgery.

Tissue reaction to absorbable endoloop, nonabsorbable titanium staples, and polymer Hem-o-lok clip after laparoscopic appendectomy

BACKGROUND AND OBJECTIVES

The standard technique for securing the base of the appendix during laparoscopic appendectomy is by absorbable endoloop ligature, although clinical reports favor the use of the stapler. Nonabsorbable Hem-o-lok clips have been shown to be an alternative technique to this. However, it is currently not clear whether nonabsorbable clips have any effects on the intestine or promote infection in the surgical area.

MATERIALS AND METHODS

Sixty Wistar albino rats were randomized into 3 treatment groups: group I (n=20) the base of the appendix was secured by endoloop 2-0 ligature; group II (n=20) dissection of the appendix was performed by a 45-mm thick stapler; and group III (n=20) the base of the appendix was secured by a Hem-o-lok plastic clip. The animals were sacrificed on the 14th and 28th days after surgery. The secured stump was used for histopathological examination.

RESULTS

There were no significant differences in histopathological changes observed on the 14th postoperative day between the groups. On the 28th postoperative day, it was proved that mild and moderate inflammation is more frequent in the endoloop and Hem-o-lok groups than in the stapler group. Reaction to a foreign body is more frequent in the endoloop than in stapler and Hem-o-lok groups.

CONCLUSION

The mildest postoperative inflammatory changes were seen in the stapler group, followed by the Hem-o-lok group. However, because of the price of the plastic clip and the simplicity of its application, its use is still favored during laparoscopic appendectomy.

Double fixation of displaced patella fractures using bioabsorbable cannulated lag screws and braided polyester suture tension bands

PURPOSE

To evaluate the effectiveness and safety of a new double fixation technique for displaced patellar fractures using bioabsorbable cannulated lag screws and braided polyester suture tension bands.

METHODS

Fifteen patients (mean age of 46.2 years) with displaced transverse or comminuted patella fractures were enrolled in this prospective study. All of the patients were treated via the open reduction internal fixation (ORIF) procedure using bioabsorbable cannulated lag screws and braided polyester suture tension bands. The patients were followed post-surgery to evaluate (1) the time required for radiographic bone union, (2) the knee joint range of motion at the time of radiographic bone union, (3) the degree of pain assessed using the visual analogue scale (VAS), (4) the function of the knee using the Lysholm score and (5) the presence of any additional complications from the surgery.

RESULTS

All of the patients were followed post-treatment for more than 1 year (range, 12-19 months; mean post-treatment follow up time, 14 months). The bone union of the fractures as seen radiographically occurred approximately 3 months from surgery in all cases without implant failure or redisplacement of the fractured site. The mean knee joint range of motion was from 0 to 134.6°, and the mean VAS score was 0.7 at the time of bone union. The mean Lysholm scores at the time of bone union and 12 months post-surgery were 86.7 and 95.7, respectively. No postoperative complications, such as infection, dislocation or breakage of the implants, were observed. Moreover, all of the patients returned to their previous activity level.

CONCLUSION

This new double fixation technique using bioabsorbable cannulated lag screws and braided polyester suture tension bands resulted in satisfactory outcomes for patella fractures without any obvious complications.

Repair of fresh open tear of Achilles tendon Tension regulation at the suture line

BACKGROUND

Lack of the timely mechanical loading of the repaired tendon is detrimental for healing progress. The current knowledge knows the appropriate time for the mechanical loading, but need to find out a suitable tool for this purpose. Therefore we present a technique based on using of an absorbable reinforcement device for tension regulation at the suture line.

METHODS

24 patients with open tear of Achilles tendon were repaired surgically, the repair was reinforced using an absorbable suture and the outcomes were prospectively assessed at 24 months.

RESULTS

No tendon lengthening or reruptures were reported; patients returned to pre-injury daily activates by fourth month. One patient reported 1cm atrophy of the calf, scar adhesion Grade 1 and ankle dorsiflexion decreased 5°.

CONCLUSION

Restoration of the continuity and actual length of repaired tendons support use of the absorbable reinforcement device for regulation of the mechanical environment at the suture line.

Comparison of a new multifilament stainless steel suture with frequently used sutures for flexor tendon repair

PURPOSE

To investigate the mechanical properties of some common suture materials currently in use and compare them with a new multifilament stainless steel suture.

METHODS

We investigated the mechanical properties of 3-0 and 4-0 Fiberwire, 3-0 Supramid, 3-0 Ethibond, and a new 3-0 and 4-0 multifilament stainless steel suture. All suture material was tested in a knotted configuration and all but the Supramid was tested in an unknotted configuration. We measured the load, elongation at failure, and stiffness during both tests.

RESULTS

The 4-0 multifilament stainless steel showed the least elongation, whereas the 3-0 multifilament stainless steel withstood the highest load of any material in both the knotted and unknotted tests. There was no difference in stiffness between the 3-0 and 4-0 multifilament stainless steel when untied; however, the 3-0 multifilament stainless steel was stiffer when tied. Soaking in a saline solution had no significant effect on the ultimate load, elongation at failure, or stiffness of any of the sutures. The 3-0 Fiberwire and 3-0 Ethibond required at least 5 throws to resist untying.

CONCLUSIONS

Multifilament stainless steel exhibited promising mechanical advantages over the other sutures tested. More research is needed to determine how this material will affect the clinical outcomes of primary flexor tendon repair.

CLINICAL RELEVANCE

With a secure attachment to the tendon, the multifilament stainless steel's lower elongation and better knot-holding ability may result in a higher force to produce a 2-mm gap and a higher ultimate tensile strength in a tendon repair.

Bacterial adherence to suture materials

BACKGROUND

Wound infections may be problematic for physicians. Whether a practitioner is managing complex penetrating trauma or a skin biopsy, there may be a need for suture closure. Suture material is an operator dependent variable and while little objective data exist to guide the choice of suture, it may play a role in wound infection. This study evaluates bacterial adherence to commonly used suture materials with a bioluminescent in vitro model.

METHODS

In all, 11 strands of size 2-0 poliglecaprone suture (Monocryl; Ethicon, Inc, Somerville, New Jersey), polypropylene suture (Prolene; Ethicon, Inc), silk suture (Ethicon, Inc), polyglycolic acid suture (Vicryl; Ethicon, Inc), and antimicrobial polyglycolic acid suture treated with triclosan (VicrylPlus; Ethicon, Inc) were immersed in a broth of Staphylococcus aureus engineered to emit photons. After biofilm formation, the suture strands were irrigated and imaged with a photon-capturing camera system yielding a total photon count that correlates with residual bacteria.

RESULTS

The Vicryl suture had the highest counts and was statistically significant in bacterial adherence versus all other sutures. No other suture material was significantly different from any other.

CONCLUSIONS

This study gives data to guide the selection of suture materials. Absorbable braided suture should not be used in closure of contaminated wounds or wounds at risk for developing infection. The antibiotic impregnated absorbable braided suture was similar to the other suture types; however, it is at risk for reverting to the properties of its untreated counterpart over time. The bacterial adherence of suture materials should be taken into account by all practitioners when closing wounds or debriding infected wounds.

Visual measurement of suture strain for robotic surgery

Minimally invasive surgical procedures offer advantages of smaller incisions, decreased hospital length of stay, and rapid postoperative recovery to the patient. Surgical robots improve access and visualization intraoperatively and have expanded the indications for minimally invasive procedures. A limitation of the DaVinci surgical robot is a lack of sensory feedback to the operative surgeon. Experienced robotic surgeons use visual interpretation of tissue and suture deformation as a surrogate for tactile feedback. A difficulty encountered during robotic surgery is maintaining adequate suture tension while tying knots or following a running anastomotic suture. Displaying suture strain in real time has potential to decrease the learning curve and improve the performance and safety of robotic surgical procedures. Conventional strain measurement methods involve installation of complex sensors on the robotic instruments. This paper presents a noninvasive video processing-based method to determine strain in surgical sutures. The method accurately calculates strain in suture by processing video from the existing surgical camera, making implementation uncomplicated. The video analysis method was developed and validated using video of suture strain standards on a servohydraulic testing system. The video-based suture strain algorithm is shown capable of measuring suture strains of 0.2% with subpixel resolution and proven reliability under various conditions.

Intelligent thermoresponsive substrate from modified overhead projection sheet as a tool for construction and support of cell sheets in vitro

Cell sheet engineering using thermoresponsive culture dishes allows harvesting of intact in vitro cell sheet. In this study, commercially available polyethylene terephthalate-based overhead projection transparency sheet (OHPS) was identified as a substrate for coating thermoresponsive poly(N-isopropylacrylamide-co-glycidylmethacrylate) (NGMA) copolymer having lower critical solution temperature of 28°C. Since OHPS is highly hydrophobic and rigid, the surface was modified by alkali treatment (OHPS-M) to functionalize the surface with carboxyl and hydroxyl groups so as to make it more suitable for efficient coating of NGMA copolymer and cell culture. To impart thermoresponsiveness, OHPS-M was coated with NGMA (OHPS-MC). Surface morphology, surface chemistry, and thermoresponsive coating were analyzed by profilometry, scanning electron microscopy, water contact angle, and Fourier transform infrared spectroscopy. The cytotoxicity, cell adhesion, and proliferation on OHPS-M and OHPS-MC were analyzed using L929 cells. Specific cytocompatibility analysis was done using SIRC (Rabbit corneal) cells. Data revealed cytocompatible nature of OHPS-M and OHPS-MC. Suitability of OHPS-MC for cell sheet harvest and transfer efficiency was assessed using primary corneal cells. Corneal cell sheet constructs retrieved by temperature variation was characterized by reverse transcriptase polymerase chain reaction for markers specific to differentiated corneal cells (keratin 3 and keratin 12) and proliferating cell nuclear antigen, and assessed for viability using fluorescein diacetate staining, tissue architecture by scanning electron microscopy, and cell-cell contacts by connexin-43 staining. The retrieved cell sheets retained corneal epithelial characteristics such as keratin 3/12, viability, and tissue architecture with intact cell-cell contacts as in native tissue. The results proved that surface modification and coating with NGMA on OHPS offer a novel biocompatible thermosensitive cell culture substrate for generating cell sheet constructs. In addition, OHPS-M can also serve as an efficient carrier tool for retrieved cell sheet.

A comparative study between two different suture materials in oral implantology

OBJECTIVE

The prospective study compares, in split-mouth design, the use of two different suture materials, silk vs. Teflon-coated, multi-filament braided polyester threads suture.

MATERIAL AND METHODS

Ten edentulous or partially edentulous patients were surgically treated for implant installation. Each side was sutured with either, randomly selected one or the other suture material. Seven days postsurgically, the sutures were removed and three knots per patient and side were collected for microbiological testing. Additionally, a piece of each suture thread was analysed before clinical use to test its susceptibility for bacterial adherence. To evaluate the patient's subjective opinion, a questionnaire based on Visual Analogue Scale had to be filled out by all included patients 1 week after the intervention.

RESULTS

The results showed a more pronounced plaque accumulation for silk sutures but there was not a statistical difference. The intraoperative handling of the silk sutures was less comfortable and the patient comfort was worse than Teflon-coated polyester suture.

CONCLUSION

The bacterial adherence on Teflon-coated polyester suture was slightly inferior than silk suture although it did not show the expected differences.

Novel strategies in tendon and ligament tissue engineering: Advanced biomaterials and regeneration motifs

Tendon and ligaments have poor healing capacity and when injured often require surgical intervention. Tissue replacement via autografts and allografts are non-ideal strategies that can lead to future problems. As an alternative, scaffold-based tissue engineering strategies are being pursued. In this review, we describe design considerations and major recent advancements of scaffolds for tendon/ligament engineering. Specifically, we outline native tendon/ligament characteristics critical for design parameters and outcome measures, and introduce synthetic and naturally-derived biomaterials used in tendon/ligament scaffolds. We will describe applications of these biomaterials in advanced tendon/ligament engineering strategies including the utility of scaffold functionalization, cyclic strain, growth factors, and interface considerations. The goal of this review is to compile and interpret the important findings of recent tendon/ligament engineering research in an effort towards the advancement of regenerative strategies.

An experimental model to investigate initial tracheal anastomosis strength

OBJECTIVES/HYPOTHESIS

Early anastomotic dehiscence is a devastating complication of segmental tracheal resection. Although wound healing, patient comorbidities, and anastomotic tension are all influential factors, there is a paucity of information available on initial tracheal stability after various tracheal anastomosis techniques in human tissue.

STUDY DESIGN

Prospective cadaver study.

METHODS

We present a novel, inexpensive pulley-based system to apply symmetric tension on the trachea in a longitudinal direction to the point of anastomotic dehiscence. The validity of this mechanism was confirmed with trials using incrementally increasing quantities of the same suture type. Twenty-four trials were then performed on 12 cadaver tracheas (six fresh and six preserved) to compare anastomotic strength with two commonly used suture materials (3-0 polyglactin [Vicryl] vs. 3-0 polydioxanone [PDS]).

RESULTS

Validation studies demonstrated that the force increased appropriately with an increasing number of sutures tested. In the tracheal anastomoses, tracheal suture pull-through was the most common mechanism of dehiscence, regardless of suture type. No significant difference in anastomotic stability was detected between the fresh versus preserved cadaver tracheas. The mean anastomotic strength was slightly greater for Vicryl (179.9 N) when compared to PDS (161.5 N), but the difference did not reach significance (P = .207).

CONCLUSIONS

We introduce an inexpensive tool for measuring initial tracheal anastomosis stability with human cadavers, which demonstrated no difference in the tracheal pull-through strength of Vicryl and PDS.

Artroplastia glenoumeral: resistência do fio de poliéster após contato com o metilmetacrilato

OBJETIVO: Os autores estudam as características do fio de poliéster (ethibond) após o contato com o metilmetacrilato (cimento ortopédico) no laboratório de resistência de materiais. MÉTODOS: Avaliam a força necessária para a ruptura bem como a elasticidade e a deformidade provocadas durante a tração no aparelho Instron 4482. Realizam análise estatística através do teste "t-student". RESULTADOS: Não encontram diferença estatisticamente significativa entre os grupos estudados. CONCLUSÃO: Concluem que o contato do metilmetacrilato com o poliéster não acarreta mudanças na suas propriedades elásticas e de resistência à tração.

Long-term biostability of self-assembling protein polymers in the absence of covalent crosslinking

Unless chemically crosslinked, matrix proteins, such as collagen or silk, display a limited lifetime in vivo with significant degradation observed over a period of weeks. Likewise, amphiphilic peptides, lipopeptides, or glycolipids that self-assemble through hydrophobic interactions to form thin films, fiber networks, or vesicles do not demonstrate in vivo biostability beyond a few days. We report herein that a self-assembling, recombinant elastin-mimetic triblock copolymer elicited minimal inflammatory response and displayed robust in vivo stability for periods exceeding 1 year, in the absence of either chemical or ionic crosslinking. Specifically, neither a significant inflammatory response nor calcification was observed upon implantation of test materials into the peritoneal cavity or subcutaneous space of a mouse model. Moreover, serial quantitative magnetic resonance imaging, evaluation of pre- and post-explant ultrastructure by cryo-high resolution scanning electron microscopy, and an examination of implant mechanical responses revealed substantial preservation of form, material architecture, and biomechanical properties, providing convincing evidence of a non-chemically or ionically crosslinked protein polymer system that exhibits long-term stability in vivo.

Repair of fresh patellar tendon rupture: tension regulation at the suture line

The reported complications of the repaired patellar tendon have been attributed to the influence of the mechanical environment on the healing process. This study postulates that the healing complications can be minimised through tension regulation at the suture line using an absorbable reinforcement device. Twelve patients with fresh patellar tendon rupture were included in the study. They were prospectively followed up for an average period of 45 months. The patients resumed their pre-injury activities at an average of 6.1 months. The active knee movement averaged 0-154.6° compared to 0-156.7° in the contralateral knee. Radiologically no patella alta, patella baja or degenerative changes in the patellofemoral joints were noted. The results support use of the absorbable reinforcement device for tension regulation at the suture line.

Anterior cruciate ligament regeneration using mesenchymal stem cells and silk scaffold in large animal model

Although in vivo studies in small animal model show the ligament regeneration by implanting mesenchymal stem cells (MSCs) and silk scaffold, large animal studies are still needed to evaluate the silk scaffold before starting a clinical trial. The aim of this study is to regenerate anterior cruciate ligament (ACL) in pig model. The micro-porous silk mesh was fabricated by incorporating silk sponges into knitted silk mesh with lyophilization. Then the scaffold was prepared by rolling the micro-porous silk mesh around a braided silk cord to produce a tightly wound shaft. In vitro study indicated that MSCs proliferated profusely on scaffold and differentiated into fibroblast-like cells by expressing collagen I, collagen III and tenascin-C genes in mRNA level. Then the MSCs-seeded scaffold was implanted in pig model to regenerate ACL. At 24 weeks postoperatively, the MSCs in regenerated ligament exhibited fibroblast morphology. The key ligament-specific extracellular matrix components were produced prominently and indirect ligament-bone insertion with three zones (bone, Sharpey's fibers and ligament) was observed. Although there was remarkable scaffold degradation, the maximum tensile load of regenerated ligament could be maintained after 24 weeks of implantation. In conclusion, the results imply that silk-based material has great potentials for clinical applications.

Biodegradation of silk biomaterials

Silk fibroin from the silkworm, Bombyx mori, has excellent properties such as biocompatibility, biodegradation, non-toxicity, adsorption properties, etc. As a kind of ideal biomaterial, silk fibroin has been widely used since it was first utilized for sutures a long time ago. The degradation behavior of silk biomaterials is obviously important for medical applications. This article will focus on silk-based biomaterials and review the degradation behaviors of silk materials.

Antibacterial protection of suture material by chlorhexidine-functionalized polyelectrolyte multilayer films

The formation of bacterial biofilms on the surface of implanted materials is a critical factor that may lead to chronic microbial infection and tissue necrosis. In the present study we analysed the stability of polyelectrolyte multilayer (ML) films on suture materials and the antibacterial effect obtained with chlorhexidine (CHX)-functionalized films built on different types of suture materials such as silk, polyester and copolymer of glycolide and L: -lactide. The comparison of Escherichia coli culture on glass coverslips and glass coverslips with ML and CHX showed at 24 h an inhibition of the bacterial relative luminescence (40.68%, P < 0.5) and at 48 h (99.46%, P < 0.001). In another way, simple soaking of suture material overnight in CHX digluconate 20% without polyelectrolyte films did not at all protect sutures from bacterial colonization but CHX-functionalized polyelectrolyte films, made from poly-L: -glutamic acid and poly-L: -lysine, inhibited Escherichia coli proliferation.