Absorbable sutures in general surgery - review, available materials, and optimum choices.

Sutures are the most versatile materials used in surgery. Despite recent technological advances and availability of novel materials such as tissue cements, it appears that surgical sutures will continue to be used for many years to come. The objective of this study was to provide an overview of the most common absorbable sutures used in general surgery. The appropriate suture choice for a particular procedure is of key importance for the success of that procedure.

The effect of an air knot on surgical knot integrity.

OBJECTIVE: Surgical trainees may tie air knots, which have a questionable tensile strength and rate of untying. The purpose of this study was to determine the effect of an air knot on knot integrity. METHODS: The 5 suture materials tested were 0-0 gauge coated polyethylene, polyglyconate, glycolide/lactide, polypropylene, and silk. The suture was tied between 2 hex screws 50 mm on center. The strands were tied using 5 square throws, and the knot tails were cut at 3-mm length. To create a standardized air knot, a round common nail measuring 3 mm in diameter was inserted between throws before tying square throw #3. The suture loop was positioned around the upper and lower hooks of the tensiometer so the location of the knot was roughly equidistant from the hooks. Ultimately, either the loop broke or the knot slipped. At that time, the peak tensile force as well as the outcome of the knot were recorded. RESULTS: A total of 480 knots were tied. The presence of an air knot significantly lowered the tension at knot failure in the glycolide/lactide (P = 0.0003), polypropylene (P = 0.0005), and silk (P = 0.0001) knot configurations. Air knots had the same integrity as surgical knots when coated polyethylene and polyglyconate suture were used. Linear regression was performed and identified both suture material (P < 0.0001) and presence of an air knot (P < 0.0001) to be independently associated with a lower tension at failure. CONCLUSIONS: Under laboratory conditions, an air knot may contribute to a lower tensile strength at failure for certain suture materials.

Mode of action analysis for liver tumors from oral 1,4-dioxane exposures and evidence-based dose response assessment.

1,4-Dioxane is found in consumer products and is used as a solvent in manufacturing. Studies in rodents show liver tumors to be consistently reported after chronic oral exposure. However, there were differences in the reporting of non-neoplastic lesions in the livers of rats and mice. In order to clarify these differences, a reread of mouse liver slides from the 1978 NCI bioassay on 1,4-dioxane in drinking water was conducted. This reread clearly identified dose-related non-neoplastic changes in the liver; specifically, a dose-related increase in the hypertrophic response of hepatocytes, followed by necrosis, inflammation and hyperplastic hepatocellular foci. 1,4-Dioxane does not cause point mutations, DNA repair, or initiation. However, it appears to promote tumors and stimulate DNA synthesis. Using EPA Guidelines (2005), the weight of the evidence suggests that 1,4-dioxane causes liver tumors in rats and mice through cytotoxicity followed by regenerative hyperplasia. Specific key events in this mode of action are identified. A Reference Dose (RfD) of 0.05mg/kgday is proposed to protect against regenerative liver hyperplasia based on a benchmark dose (BMD) approach. Based on this RfD, a maximum contaminant level goal of 350µg/L is proposed using a default relative source contribution for water of 20%.

A randomized, prospective trial evaluating surgeon preference in selection of absorbable suture material.

This study is the first double-blinded, randomized comparison of two absorbable sutures. To better understand product characteristics and surgeon preference, we conducted a study of two similar-appearing FDA-approved sutures, glyconate and poliglecaprone 25. Four dermatologic surgeons were enlisted. A total of 48 patients with 53 surgical sites were examined. One half of each surgical wound was closed with one type of suture and the other half with the other type. Each half was evaluated for product characteristics. There was no statistically significant difference in surgeon preference for glyconate versus poliglecaprone 25 (P=0.64). Of the cohort preferring poliglecaprone 25, there was a correlation with speed of closure (P=0.06). Of the surgeons that preferred glyconate, we found significantly better visibility (P=0.03), reduced suture breakage during knot tying (P=0.05), and correlation with better handling properties (P=0.06) associated with that preference. The data from this study will enable products to be designed towards these needs and allow surgeons to select sutures that more precisely fit their particular requirements.

Assessing the impact of the duration and intensity of inhalation exposure on the magnitude of the variability of internal dose metrics in children and adults.

The objective of this study was to assess the impact of the exposure duration and intensity on the human kinetic adjustment factor (HKAF). A physiologically based pharmacokinetic model was used to compute target dose metrics (i.e. maximum blood concentration (C(max)) and amount metabolized/L liver/24 h (Amet)) in adults, neonates (0-30 days), toddlers (1-3 years), and pregnant women following inhalation exposure to benzene, styrene, 1,1,1-trichloroethane and 1,4-dioxane. Exposure scenarios simulated involved various concentrations based on the chemical's reference concentration (low) and six of U.S. EPA's Acute Exposure Guideline Levels (AEGLs) (high), for durations of 10 min, 60 min, 8 h, and 24 h, as well as at steady-state. Distributions for body weight (BW), height (H), and hepatic CYP2E1 content were obtained from the literature or from P3M software, whereas blood flows and tissue volumes were calculated from BW and H. The HKAF was computed based on distributions of dose metrics obtained by Monte Carlo simulations [95th percentile in each subpopulation/median in adults]. At low levels of exposure, ranges of C(max)-based HKAF were 1-6.8 depending on the chemical, with 1,4-dioxane exhibiting the greatest values. At high levels of exposure, this range was 1.1-5.2, with styrene exhibiting the greatest value. Neonates were always the most sensitive subpopulation based on C(max), and pregnant women were most sensitive based on Amet in the majority of the cases (1.3-2.1). These results have shown that the chemical-specific HKAF varies as a function of exposure duration and intensity of inhalation exposures, and sometimes exceeds the default value used in risk assessments.

Tensile strength study of the abdominal wall following laparotomy synthesis using three types of surgical wires in Wistar rats.

PURPOSE: To study the tensile strength of the abdominal wall following laparotomy synthesis utilizing three types of surgical wires. METHODS: Thirty Wistar rats were randomized into three groups of ten rats each. Each group underwent a 3cm-laparotomy which was closed with 3-0 polyglactin 910, polyglecrapone and catgut wires. After 63 days, euthanasia was performed and part of the abdominal wall was removed with which a strip was produced measuring 2.0 cm in length by 6.0 cm in width comprising the abdominal muscles with the implanted mesh. The sample was fixed in a mechanical test machine in which constant force was applied contrary to the tissue strips. Maximum force was considered, expressed in Newton, until full rupture of the tissue occurred. The non-parametrical Kruskal - Wallis test was used for the statistical analysis, admitting p

Tensile strength study of the abdominal wall following laparotomy synthesis using three types of surgical wires in Wistar rats

PURPOSE: To study the tensile strength of the abdominal wall following laparotomy synthesis utilizing three types of surgical wires. METHODS: Thirty Wistar rats were randomized into three groups of ten rats each. Each group underwent a 3cm-laparotomy which was closed with 3-0 polyglactin 910, polyglecrapone and catgut wires. After 63 days, euthanasia was performed and part of the abdominal wall was removed with which a strip was produced measuring 2.0 cm in length by 6.0 cm in width comprising the abdominal muscles with the implanted mesh. The sample was fixed in a mechanical test machine in which constant force was applied contrary to the tissue strips. Maximum force was considered, expressed in Newton, until full rupture of the tissue occurred. The non-parametrical Kruskal - Wallis test was used for the statistical analysis, admitting p<0.05. RESULTS: The average strength of the catgut group was slightly lower (33.50 N) than that of the polyglactin group (34.23 N), the difference not being statistically significant (p=0.733). The polyglecaprone group was the one which presented the lowest strength value of all three wires analyzed (29.86 N). No statistical difference was obtained when comparing the strength values of the polyglecaprone group and the catgut group (p=0.06 ). However, when the polyglecaprone group was compared to the polyglactin 910 group no statistical difference was obtained (p=0.029). CONCLUSION: The polyglactin wire presented the highest tensile strength among the three wires analyzed, such value being statistically significant when polyglactin was compared to the polyglecaprone wire.

OBJETIVO: Estudar a resistência tênsil da parede abdominal após síntese de laparotomia utilizando três tipos de fios cirúrgicos. MÉTODOS: Trinta ratos da linhagem Wistar randomizados em três grupos de dez exemplares cada um. Em cada grupo fez-se uma laparotomia de dois centímetros que foi fechada com fios 3-0 de poliglactina 910, poliglecaprone e categute. Após 63 dias, foi feita a eutanásia e retirou-se uma área da parede abdominal com a qual fez-se uma tira medindo 2,0 cm de comprimento por 6,0 cm de largura englobando os músculos abdominais com a tela implantada. A amostra foi fixada em máquina de ensaios mecânicos na qual se aplicou força constante contrária às tiras de tecido. Foi considerada a força máxima expressa em Newton até ocorrer a ruptura total da amostra. Para a análise estatística, utilizou-se teste não paramétrico de Kruskal - Wallis admitindo-se p<0,05. RESULTADOS: A média de resistência do grupo categute foi ligeiramente menor (33.50 N) ao da poliglactina (34.23 N), sendo essa diferença não estatisticamente significativa (p=0,733). O grupo poliglecaprone foi o que apresentou menor resistência entre os três fios analisados (29.86 N). Comparando as resistências do grupo poliglecaprone ao grupo categute não se obteve significância estatística (p=0,06). Entretanto quando o grupo poliglecaprone foi comparado à poliglactina 910 houve significância estatística (p=0,029). CONCLUSÃO: O fio de poliglactina apresentou a maior resistência tênsil dentre os três fios analisados, sendo esta estatisticamente significativa quando comparado ao fio de poliglecaprone.

Strength and knot security of braided polyester and caprolactone/glycolide suture.

BACKGROUND: Appropriate suture selection is necessary in providing mechanical stability to soft tissue reconstructions. Caprolactone/glycolide (Panacryltrade mark) became a popular suture, possessing excellent handling properties; however, clinical observations questioned the knot security of caprolactone/glycolide. Caprolactone/glycolide is still available on many commercial suture anchor systems. This study compared the security of the knots and ultimate tensile strength of braided caprolactone/glycolide suture to that of a commonly used suture material, braided polyester (Ethibondtrade mark). MATERIALS: Suture knots of No. 2 braided polyester suture and No. 2 braided caprolactone/glycolide suture were submersed in a physiologic saline solution and stressed using a continuous (non-cyclic) load, simulating a single maximal loading event in a clinical setting. Continuous loading was done to achieve clinical suture knot failure (3-mm knot slippage), then continued until catastrophic suture failure (suture breakage) occurred. Ten trials of each suture were tested. RESULTS: Force required to cause knot slippage of 3 mm was greater for braided polyester than for braided caprolactone/glycolide (p <. 0001, unpaired Students' t-test). Forces resulting in catastrophic failure were greater for braided polyester than braided caprolactone/glycolide (p = .0284, unpaired Students' t-test). CONCLUSIONS: These data have important implications in the selection of suture materials for repair of soft tissue injuries. In the clinical setting, a single maximal loading event may result in suture failure. These data indicate that braided polyester possesses superior in-vitro mechanical properties and suggest that braided polyester may provide greater security in-vivo than braided caprolactone/glycolide suture.

Breaking strength and diameter of absorbable sutures after in vivo exposure in the rat.

Although absorbable sutures are commonly used in clinical practice, the rate of decay of strength in various tissues has not been studied. The purpose of this study was to assess breaking strength (BS) and diameter of monofilament (chromic gut, polydiaxanone, Maxon, Monocryl) and multifilament (Vicryl, Dexon, Polysorb) absorbable sutures implanted in various sites and measured at specific time intervals. A 15 cm length of 4-0 suture from a single lot of each material was implanted in the pleural space, rectus abdominus muscle, subcutaneous tissue, intravascular space, peritoneal cavity, and stomach lumen in the rat. A precipitous decrease in BS was noted in all multifilament sutures after 7 days, and in chromic gut and Monocryl sutures after 1 day. Polydiaxanone and Maxon sutures maintained the highest BS over the 28-day period, 71 per cent and 59 per cent of their initial BS, respectively. Suture diameter remained essentially unchanged except for chromic gut and the multifilament sutures which exhibited increased diameter. This increase was attributed to inflammatory tissue infiltration.

Surgical materials and wound closure techniques.

Recent innovations in surgical materials have helped to enhance wound healing and protect surgical wounds from infection. Materials such as polyglyconate have been evaluated in equine tissues and found efficacious. Other materials, such as poliglecaprone 25, appear to have qualities useful to equine surgery but are untested in equine tissues. Care must be taken to fully evaluate a new surgical material because its usefulness in equine tissues may not match that in human or laboratory animal tissues. Furthermore, use of disposable materials in surgery, although considered ideal for maintenance of sterility, may come under more scrutiny in the future as environmental issues gain prominence. We tend to reserve disposable materials for prolonged procedures and for procedures that carry high risk of failure if infection develops.

[Comparative evaluation of tensile strength of absorbable threads Dexon and Maxon. Experimental studies]. / Ocena porównawcza wytrzymalosci na zrywanie syntetycznych nici wchlanialnych Dexon i Maxon. Badania doswiadczalne.

This paper submits strength tests on Dexon and Maxon resorbable sutures at the knot and without a knot, the breaking resulting from hydrolysis. The tests were performed on rats, by comparing Maxon monofilament suture with Dexon woven suture. The dissections were done 3, 7, 21 and 42 days after the implantation. What we found out was a remarkably slower process of strength loss displayed by Maxon sutures in time after the implantation. After 21 days, Dexon sutures displayed a minimal strength value, whereas Maxon sutures still retained ca 60% of the initial properties.