A review of sutures and other skin closure materials

Poly(Lactic Acid) Blends with Poly(Trimethylene Carbonate) as Biodegradable Medical Adhesive Material

A novel medical adhesive was prepared by blending poly(lactic acid) (PLA) with poly(trimethylene carbonate) (PTMC) in ethyl acetate, and the two materials were proven to be biodegradable and biocompatible. The medical adhesive was characterized by ¹H nuclear magnetic resonance (¹HNMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The water vapor transmission rate (WVTR) of this material was measured to be 7.13 g·cm⁻²·24 h⁻¹. Its degree of comfortability was confirmed by the extensibility (E) and the permanent set (PS), which were approximately 7.83 N·cm⁻² and 18.83%, respectively. In vivo tests regarding rabbit immunoglobulin M (IgM), rabbit immunoglobulin G (IgG), rabbit bone alkaline phosphatase (BALP), rabbit interleukin 6 (IL-6), rabbit interleukin 10 (IL-10), rabbit tumor necrosis factor α(TNFα), glutamic-oxaloacetic transaminase (AST/GOT), glutamic-pyruvic transaminase (ALT/GPT), alkaline phosphatase (AKP), blood urea nitrogen (BUN) and creatinine (Cr) indicated that the PLA-PTMC medical adhesive was not harmful to the liver and kidneys. Finally, pathological sections indicated that PLA-PTMC was more effective than the control group. These data suggest that in addition to having a positive effect on hemostasis and no sensibility to wounds, PLA-PTMC can efficiently prevent infections and has great potential as a medical adhesive.

Effect of thread embedding acupuncture for facial wrinkles and laxity: a single-arm, prospective, open-label study

Background

There is a growing trend for patients to seek the least invasive treatments with less risk of complications and downtime for facial rejuvenation. Thread embedding acupuncture has become popular as a minimally invasive treatment. However, there is little clinical evidence in the literature regarding its effects.

Methods

This single-arm, prospective, open-label study recruited participants who were women aged 40-59 years, with Glogau photoaging scale III-IV. Fourteen participants received thread embedding acupuncture one time and were measured before and after 1 week from the procedure. The primary outcome was a jowl to subnasale vertical distance. The secondary outcomes were facial wrinkle distances, global esthetic improvement scale, Alexiades-Armenakas laxity scale, and patient-oriented self-assessment scale.

Results

Fourteen participants underwent thread embedding acupuncture alone, and 12 participants revisited for follow-up outcome measures. For the primary outcome measure, both jowls were elevated in vertical height by 1.87 mm (left) and 1.43 mm (right). Distances of both melolabial and nasolabial folds showed significant improvement. In the Alexiades-Armenakas laxity scale, each evaluator evaluated for four and nine participants by 0.5 grades improved. In the global aesthetic improvement scale, improvement was graded as 1 and 2 in nine and five cases, respectively. The most common adverse events were mild bruising, swelling, and pain. However, adverse events occurred, although mostly minor and of short duration.

Conclusion

In this study, thread embedding acupuncture showed clinical potential for facial wrinkles and laxity. However, further large-scale trials with a controlled design and objective measurements are needed.

Development of novel double-decker microneedle patches for transcutaneous vaccine delivery

Microneedle (MN) patches have great potential as transcutaneous vaccine delivery devices because MNs can effectively deliver vaccine antigen into the skin through the micropores formed in the stratum corneum by low-invasive and painless skin puncturing. This study aims to develop novel double-decker MN patches which have not only high safety and efficacy but also broad applicability to various vaccine antigens. We developed two types of MN patches (PGA-MN and Nylon-MN) that are made from polyglycolic acid and Nylon-6. In pre-clinical studies, both MN patches could demonstrably deliver antigens into resected human dermal tissue, prolong antigen deposition and increase antigen-specific IgG levels after vaccination compared with conventional injections. We demonstrated both MN patches could be safely applied to human skin because no broken MNs or significant skin irritation were observed after applications in the clinical research. PGA-MN was suggested to be superior to Nylon-MN regarding human skin puncturability based on measurements of transepidermal water loss and needle failure force. A high content of tetravalent influenza hemagglutinin antigens loaded on PGA-MN could stably maintain HA titers at 35°C for 1year. Overall, double-decker MN patches can reliably and safely puncture human skin and are promising as effective transcutaneous vaccine delivery devices.

Application of Materials as Medical Devices with Localized Drug Delivery Capabilities for Enhanced Wound Repair

The plentiful assortment of natural and synthetic materials can be leveraged to accommodate diverse wound types, as well as different stages of the healing process. An ideal material is envisioned to promote tissue repair with minimal inconvenience for patients. Traditional materials employed in the clinical setting often invoke secondary complications, such as infection, pain, foreign body reaction, and chronic inflammation. This review surveys the repertoire of surgical sutures, wound dressings, surgical glues, orthopedic fixation devices and bone fillers with drug eluting capabilities. It highlights the various techniques developed to effectively incorporate drugs into the selected material or blend of materials for both soft and hard tissue repair. The mechanical and chemical attributes of the resultant materials are also discussed, along with their biological outcomes in vitro and/or in vivo. Perspectives and challenges regarding future research endeavors are also delineated for next-generation wound repair materials.

Induction of immune gene expression and inflammatory mediator release by commonly used surgical suture materials: an experimental in vitro study

Background

Surgeons have a range of materials to choose from to complete wound closure, yet surprisingly very little is still known about the body’s immune response to the suture materials in current use. The growing literature of adverse suture material reactions provided the objective of this study, to use in vitro assays to quantify levels of inflammation produced by seven commonly used suture materials in surgical procedures.

Methods

Human monocyte/macrophage THP-1 cells were exposed to suture materials for 1, 3 and 5 days. Gene expression and protein secretion of six inflammatory cytokines and two cell surface markers were assessed using qPCR and ELISA respectively, with LPS exposure providing a positive control. Furthermore, a IL-1β/IL-1RA marker ratio was assessed to determine the balance between pro-/anti-inflammatory expression.

Results

The findings from our in vitro study suggest that four commonly used suture materials cause upregulation of pro-inflammatory markers indicative of an early foreign body reaction, with no balance from anti-inflammatory markers.

Conclusions

As prolonged early pro-inflammation is known to produce delayed wound healing responses, the knowledge produced from this study has potential to improve informed surgical decision making and patient safety. This work has the capability to reduce suture-related adverse immune reactions, and therefore positively affect patient outcomes.

Polymer sutures for simultaneous wound healing and drug delivery - A review

Drug delivery using suitable polymeric devices has gathered momentum in the recent years due to their remarkable properties. The versatility of polymeric materials makes them reliable candidates for site targeted drug release. Among them biodegradable sutures has received considerable attention because they offer great promises in the realm of drug delivery. Sutures have been found to be an effective strategy for the delivery of antibacterial agents or anti-inflammatory drugs to the surgical site. Recent developments yielded sutures with improved mechanical properties, but designing sutures with all the desirable properties is still under investigation. This review is an attempt to analyze the recent developments pertaining to biologically active sutures emphasizing their potential as drug delivery vehicle.

ATN-161 Peptide Functionalized Reversibly Cross-Linked Polymersomes Mediate Targeted Doxorubicin Delivery into Melanoma-Bearing C57BL/6 Mice

PHSCN peptide (licensed as ATN-161) is an effective α₅β₁ integrin inhibitor that has advanced to phase II clinical trials to treat solid tumors. Here we developed ATN-161 functionalized self-cross-linkable and intracellularly de-cross-linkable polymersomes (ATN/SCID-Ps) for highly efficient and targeted delivery of doxorubicin hydrochloride (DOX·HCl) into B16F10 melanoma-bearing C57BL/6 mice. ATN/SCID-Ps exhibited a high loading capacity of DOX·HCl. The size of DOX-loaded ATN/SCID-Ps (DOX-ATN/SCID-Ps) decreased from 150 to 88 nm with increasing ATN surface densities from 0 to 100% (mol/mol). DOX-ATN/SCID-Ps were robust with low drug leakage under physiological conditions while quickly releasing DOX with the addition of 10 mM glutathione. MTT assay results displayed that DOX-ATN/SCID-Ps induced ATN density-dependent antitumor activity to α₅β₁ integrin overexpressing B16F10 melanoma cells, in which 56% ATN-161 was optimal. Flow cytometry and CLSM studies revealed significantly more efficient internalization and cytoplasmic DOX release in B16F10 cells for DOX-ATN/SCID-Ps than for DOX-SCID-Ps (nontargeting control) as well as clinically used pegylated liposomal doxorubicin (DOX-LPs). DOX-ATN/SCID-Ps displayed a long blood circulation time (elimination half-life = 4.13 h) and 4 times higher DOX accumulation in B16F10 bearing C57BL/6 mice than DOX-LPs. Interestingly, DOX-ATN/SCID-Ps exhibited a superior maximum-tolerated dose of over 100 mg DOX·HCl/kg, 10 times higher than DOX-LPs. Remarkably, DOX-ATN/SCID-Ps could significantly inhibit the growth of aggressive B16F10 melanoma with little adverse effects via either multiple or single injection of total dosage of 100 mg DOX·HCl/kg, resulting in greatly improved survival rates as compared to DOX-LPs. ATN/SCID-Ps are appealing nanovehicles for targeted chemotherapy of α₅β₁ integrin positive solid tumors.

Mussel-inspired hydrogel tissue adhesives for wound closure

Tissue adhesives have been introduced as a promising alternative for the traditional wound closure method of suturing.

Buried absorbable polyglactin 910 sutures do not result in stronger wounds in porcine full thickness skin incisions

OBJECTIVE

To test the hypothesis that the mechanical strength of wounds closed with a combination of buried dermal absorbable sutures and superficial nonabsorbable nylon sutures will be higher than wounds closed with only superficial nonabsorbable nylon sutures.

METHODS

Four Yucatan pigs were anesthetized and each received four 4.5cm full thickness incisions on their dorsal surfaces, placed 8cm apart. Half of all incisions were randomly allocated and repaired with 3-0 polyglactin 910 (Vicryl(™)) buried dermal absorbable sutures and superficial 3-0 nylon sutures, using a simple interrupted pattern. The other half received only 3-0 nylon sutures. Two pigs were humanely euthanized at day 10, with specimen harvest for mechanical testing; the other two pigs had superficial nylon sutures removed at day 10, as per current clinical practice, and were humanely euthanized at day 42, with specimen harvest for mechanical testing. Tensile loads were applied perpendicularly to the wounds with a displacement rate of 40mm per minute.

RESULTS

Wounds at day 42 were >9 times stronger than wounds at day 10 (p<0.0001). There was no difference in average wound strength at either day 10 or day 42 between wounds with and without buried dermal absorbable sutures.

SIGNIFICANCE

Buried dermal absorbable sutures failed to provide additional wound support at either 10 or 42 days. This result may have immediate implications for clinicians who perform cutaneous surgery and keep superficial sutures in for at least 10 days. Future research will be directed to shorter time studies, other buried dermal absorbable suture materials, and alternatives to buried dermal absorbable sutures.

Design of Xylose-Based Semisynthetic Polyurethane Tissue Adhesives with Enhanced Bioactivity Properties

Developing biocompatible tissue adhesives with high adhesion properties is a highly desired goal of the tissue engineering due to adverse effects of the sutures. Therefore, our work involves synthesis, characterization, adhesion properties, protein adsorption, in vitro biodegradation, in vitro and in vivo biocompatibility properties of xylose-based semisynthetic polyurethane (NPU-PEG-X) bioadhesives. Xylose-based semisynthetic polyurethanes were developed by the reaction among 4,4'-methylenebis(cyclohexyl isocyanate) (MCI), xylose and polyethylene glycol 200 (PEG). Synthesized polyurethanes (PUs) showed good thermal stability and high adhesion strength. The highest values in adhesion strength were measured as 415.0 ± 48.8 and 94.0 ± 2.8 kPa for aluminum substrate and muscle tissue in 15% xylose containing PUs (NPU-PEG-X-15%), respectively. The biodegradation of NPU-PEG-X-15% was also determined as 19.96 ± 1.04% after 8 weeks of incubation. Relative cell viability of xylose containing PU was above 86%. Moreover, 10% xylose containing NPU-PEG-X (NPU-PEG-X-10%) sample has favorable tissue response, and inflammatory reaction between 1 and 6 weeks implantation period. With high adhesiveness and biocompatibility properties, NPU-PEG-X can be used in the medical field as supporting materials for preventing the fluid leakage after abdominal surgery or wound closure.

Outcomes of polydioxanone knotless thread lifting for facial rejuvenation

BACKGROUND

Thread lifting is a minimally invasive technique for facial rejuvenation. Various devices for thread lifting using polydioxanone (PDO) are popular in aesthetic clinics in Korea, but there have been a few studies regarding its use.

OBJECTIVE

To describe PDO thread and techniques adopted to counteract the descent and laxity of the face.

METHODS

A retrospective chart review was conducted over a 24-month period. A total of 31 thread lifting procedures were performed. On each side, 5 bidirectional cog threads were used in the procedure for the flabby skin of the nasolabial folds. And, the procedure was performed on the marionette line using 2 twin threads.

RESULTS

In most patients (87%), the results obtained were considered satisfactory. Consensus ratings by 2 physicians found that objective outcomes were divided among "excellent," "good," "fair," and "poor." Texture wise, the outcome ratings were 13 as excellent and 9 as good. Lifting wise, ratings were 11 as excellent and 6 as good. The incidence of complications was low and not serious.

CONCLUSION

Facial rejuvenation using PDO thread is a safe and effective procedure associated with only minor complications when performed on patients with modest face sagging, fine wrinkles, and marked facial pores.

Clinical applications of surgical adhesives and sealants

In the United States and Europe, the number of topical adhesives, surgical sealants, and hemostats approved for use in the surgical setting is ever expanding although no single device fills all medical and surgical needs to replace sutures. As more surgical procedures are performed through laparoscopic and robotic approaches, these devices are becoming more important, and current research is focused on solving the limitations of conventional wound treatments. This review article discusses clinical applications of various biologically derived and synthetic products that are currently available to surgeons and those that are in development.

Synthesis and properties of temperature-sensitive and chemically crosslinkable poly(ether-urethane) hydrogel

The PEU-MA solutions can gelate at physiological temperature, and be further crosslinked by UV light.

Systematic review of absorbable vs non-absorbable sutures used for the closure of surgical incisions

AIM

To report a systematic review of published randomized controlled trials (RCTs) investigating the role of absorbable suture (AS) against non-AS (NAS) used for the closure of surgical incisions.

METHODS

RCTs investigating the use of AS vs NAS for the closure of surgical incisions were statistically analysed based upon the principles of meta-analysis and the summated outcomes were represented as OR.

RESULTS

The systematic search of medical literature yielded 10 RCTs on 1354 patients. Prevalence of wound infection (OR = 0.97; 95%CI: 0.56, 1.69; Z = 0.11; P = 0.92) and operative morbidity (P = 0.45) was comparable in both groups. Nonetheless, the use of AS lead to lower risk of wound break-down (OR = 0.12; 95%CI: 0.04, 0.39; Z = 3.52; P < 0.0004).

CONCLUSION

This meta-analysis of 10 RCTs demonstrates that the use of AS is similar to NAS for skin closure for surgical site infection and other operative morbidities. AS do not increase the risk of skin wound dehiscence, rather lead to a reduced risk of wound dehiscence compared to NAS.

A Randomized Study Comparing Skin Staples with Subcuticular Sutures for Wound Closure at Caesarean Section in Black-Skinned Women

This study aimed to compare patients' satisfaction and outcome of caesarean section wound closure by skin staples and subcuticular suture at discharge and 6 weeks of postoperation. It was a randomized controlled trial of pregnant women scheduled for caesarean section at the University College Hospital, Ibadan, Nigeria, allocating them to wound closure by skin staples or subcuticular suture. Pain was assessed using the box numeric pain scale. Scar assessments were by patient, research nurse, and independent observers using the visual analogue scale, modified patient observer scar assessment scale, and patient satisfaction scale. Operation time (minutes) was significantly shorter in the staple group, 40.26 (±16.53) compared to 47.55 (±14.55) in the suture group (P = 0.025). Skin closure time (seconds) was significantly less in the staple group, 118.62 (±69.68) versus 388.70 (±170.40) in the suture group (P ≤ 0.001). There was no difference in pain experienced, wound assessment by the participants, and patients' satisfaction. Participants in the staple group scored higher on both scar assessment scales by the nurse (P = 0.044). Cost comparison analysis showed that staple use costs significantly more than suture use (P < 0.001). The perceived benefit of subcuticular suture over skin staples was not observed and participants were satisfied with both wound closure techniques.

Hydroxyapatite and silk combination-coated dental implants result in superior bone formation in the peri-implant area compared with hydroxyapatite and collagen combination-coated implants

PURPOSE

The objective of this study was to compare bone formation after installation of uncoated (UC), hydroxyapatite-coated (HA), collagen plus HA-coated (CH), and silk plus HA-coated (SH) implants.

MATERIALS AND METHODS

Implants in the UC group had acid-etched surfaces. Surface coating was applied using the aerosol deposition method. Cellular responses on the coated surfaces were examined with scanning electron microscopy. Cellular responses to the surfaces were studied with the corresponding coated discs and MG63 cells. Subsequently, 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alkaline phosphatase (ALP) assays were performed. Peri-implant bone formation was evaluated with the rabbit tibia model. Twenty-four implants from each group were installed. The animals were sacrificed 6 weeks after implant installation. Peri-implant bone formation and implant-to-bone contact were measured in histologic sections. Significance of differences across groups was evaluated using analysis of variance.

RESULTS

Scanning electron microscopic images showed that the CH and SH groups exhibited cells that appeared more spread out than those in the other groups. The SH group exhibited the highest value in the MTT assay. The CH group exhibited the highest level of ALP activity. Comparisons of these modifications with the acid-etched surfaces showed that the CH and SH groups displayed significantly greater peri-implant bone formation (P < .001).

CONCLUSION

The SH group displayed significantly greater new bone formation and bone-to-implant contact than did the other groups.

LiquiBand® Surgical S topical adhesive versus sutures for the closure of laparoscopic wounds. A randomized controlled trial

Cyanoacrylate adhesives offer the surgeon and patient an alternative to subcuticular suturing. LiquiBand® Surgical S (LBSS) is a new formulation with a blend of monomeric n-butyl and 2-octyl cyanoacrylates. In this study, the effectiveness, safety, and clinical utility of LBSS was compared to Vicryl^™ sutures for the closure of laparoscopic incisions. This was a prospective randomized study of LBSS skin adhesive versus Vicryl^™ sutures for the topical closure of laparoscopic surgical incisions. Subjects were asked to return at 2 weeks postsurgery to report complications and adverse events. Wounds were evaluated for apposition and cosmesis using a modified Hollander Wound Evaluation Scale (HWES). The Shapiro-Wilk test of normality was done. Independent-samples T test, Mann Whitney U test, and chi-square test were used to compare variables between the two wound closure methods. A total of 114 subjects participated in this trial completing all aspects of the study. Fifty-five subjects received sutures for topical wound closure, with 59 subjects receiving LBSS. Surgeons were found to be satisfied with 100 % of all applications using the LBSS device. One hundred percent of wounds closed with sutures and 98.9 % wounds closed with LBSS achieving an optimal HWES of 0. There was no statistical difference in cosmesis or complications for either method. Closure with LBSS was significantly faster by a mean of 2 min. LiquiBand® Surgical S is as good as sutures for the closure of laparoscopic wounds in terms of cosmesis and complications with the added benefit of being significantly faster.

Comparison of cosmetic outcomes of absorbable versus nonabsorbable sutures in pediatric facial lacerations

OBJECTIVE

We sought to compare cosmetic outcomes, complication rates, and patient/caregiver satisfaction of absorbable versus nonabsorbable sutures in children.

METHODS

Healthy patients, 1 to 18 years old, with facial lacerations 1 to 5 cm, were randomized to repair with fast-absorbing catgut (FAC) or nylon (NYL) sutures. Patients returned in 4 to 7 days and in 3 to 4 months, at which time photographs and caregiver surveys were completed. Unlike part I, all FAC sutures were permitted to absorb rather than be removed. Using a 100-mm visual analog scale (VAS), a noninferiority (NI) design was applied, with a difference of less than 15 mm considered clinically equivalent. Caregivers and 3 blinded physicians independently rated the scars via photographs.

RESULTS

Ninety-eight patients were enrolled, 76 caregiver surveys were completed, and 61 (29 FAC, 32 NYL) had photographs scored by physicians. The mean physician VAS scores for FAC and NYL were 57.6 and 67.6, respectively (difference, -10.0; 95% confidence interval, -19.1 to -0.4); thus, NI could not be established. The mean caregiver VAS scores for the FAC and NYL groups were 93.8 and 86.6, respectively (difference, 7.2; 95% confidence interval, -4.9 to 13.9); thus, NI of FAC was established. There were no significant differences in rates of infection, wound dehiscence, or keloid formation. In terms of future preference, caregivers favored FAC (33/33) over NYL (26/36) (P < 0.01).

CONCLUSIONS

Caregiver VAS scores showed NI of FAC, which were also preferred by the caregivers. However, NI for FAC could not be demonstrated by blinded physicians with respect to cosmetic outcomes.

Management of haemostasis in surgery: sealant and glue applications

Blood loss has always been a sensitive issue in surgery. Traditional techniques, such as suturing and electrocautery, have drastically reduced operatory bleeding. Unfortunately, wound edges and point application devices are frequently characterized by bleeding and infections. Over the past 20 years, haemostatic agents and tissue sealants have been developed and now are currently used, along with classic suture in various surgical specialties. Their fluid nature allows management of blood loss along any point of the wound and tissue repair. This review presents an overview of the most diffused haemostatic sealants, focusing on their main use in surgery and their adverse effects.

[Mechanical behaviour of three types of surgical knots using 4/0 monofilament]

OBJECTIVE

To experimentally study the behaviour of 4 types of monofilament with 3 knotting techniques, very often used in surgery, employing mechanical tests.

MATERIAL AND METHODS

Four 4/0 monofilaments were chosen, two of nylon, and the other two of polypropylene. Three types of knot designs were made with each thread. The first design (D-S-S) consisted of a double half-knot (D) followed by one single (S) in the opposite direction, a third S in turn in the opposite direction. The configuration of the second design was D-S-D, and the third, S-S-D. A mechanical fracture test was performed by stretching the thread at a rate of 4N/s, the force and deformation being recorded at intervals of 100 ms.

RESULTS

There was a decrease in the force and deformation in the tests on threads with knots compared to threads without knots. In all cases the rupture of the thread occurred in the knot area, presumably due to damage caused to the thread during the knotting process. The D-S-D knot had the greatest resistance with polypropylene threads, and S-S-D provided the greatest resistance with nylon threads

CONCLUSIONS

Polypropylene threads, with D-S-D knots, should be more indicated to suture tissues that have to support great forces and with little deformation of the suture (e.g., tendons). Nylon threads, with S-S-D knots, would be better indicated for tissues that have to support smaller forces and that require greater elasticity (e.g., skin).