Polydioxanone Threads for Facial Rejuvenation: Analysis of Quality Variation in the Market.

BACKGROUND: Beside botulinum-toxin injections and hyaluronic acid fillers, thread lifts have established themselves as the third column of minimally invasive facial rejuvenation. Most commonly, barbed threads for this approach are made out of polydioxanone, a material known for decades from application in resorbable sutures. The clinical efficacy and the putative material safety of polydioxanone have fueled the popularity of thread lifts. METHODS: The present study highlights significant variation among six commercially available threads in microstructure, tensile strength, elasticity, anchoring capacity in human tissue, and biocompatibility. RESULTS: Despite their license to be marketed and sold in the European Union, some products performed significantly worse than others on material testing, and even displayed cytotoxic characteristics. CONCLUSION: The results of this study are highly relevant for clinicians and may be linked to various typical side effects of polydioxanone threads for facial rejuvenation.

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.

Quantitative assessment and determinants of suture-holding capacity of human pancreas.

BACKGROUND: Hard pancreas is welcome by surgeons performing resective pancreatic surgery, because it is believed to offer better suture holding capacity (SHC), thus decreasing the risk for a postoperative leak. However, neither the actual SHC of pancreatic tissue in humans nor its determinants have been studied. METHODS: We directly measured SHC for polydioxanone 5-0 suture and tissue hardness at the pancreatic isthmus in 53 human pancreata using a dynamometer and a durometer. A histologic score based on fibrosis grade, fat content, pancreatic duct size, and signs of chronic pancreatitis was calculated for every sample. We tested the hypothesis that SHC of the pancreas was proportional to tissue hardness, and evaluated the role of different possible histomorphologic determinants of SHC. RESULTS: Suture-holding capacity correlated perfectly with tissue hardness (r = 0.98; P < 0.001; 95% confidence interval, 0.96-0.99). The histologic score showed a stronger correlation with both parameters than any single histologic parameter. The SHC of transductal sutures was significantly higher than that of pure transparenchymal sutures. The SHC and hardness were significantly lower in patients who developed a clinically relevant pancreatic fistula postoperatively. CONCLUSIONS: A mixture of histomorphologic features of human pancreas determines its tissue hardness and SHC. Involvement of the main pancreatic duct in the suture line appears to increase the mechanical strength of the pancreatic anastomosis.

Knot integrity as a function of suture expiration.

OBJECTIVE: To test the integrity of knots tied with expired suture and non-expired suture, using 5 different suture materials. STUDY DESIGN: Knots were tied using expired and non-expired chromic catgut, polyglactin 910, polydioxanone, silk, or coated polyester. Expired sutures were a mean of 10.5 years past the date of expiration stamped on the packaging. Suture packaging was inspected for any flaws or humidity. There were 116 knots with expired suture and 109 non-expired knots. All knots were tied by hand. Suture was soaked in 0.9% sodium chloride for 60 seconds and subsequently transferred to a tensiometer where the tails of the knots were cut to 3 mm length. We compared the tensile strength of knots using a tensiometer to pull the knots until the suture broke or untied. A minimum of 30 knots were needed in order to detect a statistically significant main effect for expired and non-expired sutures with 80% power and a 5% chance of type I error. RESULTS: A total of 225 knots were tied. Overall, we found no difference in mean tension between expired suture (77.5 ± 31.7 N) and non-expired suture at failure (81.9 ± 30.2 N). All the sutures broke at the knot and none untied. Expired chromic and polydioxanone were significantly weaker than the non-expired suture of the same material (p = 0.002 and p = 0.001, respectively). There was no statistically significant difference in tensile strength between expired absorbable or permanent suture materials. Based on a univariate analysis of variance ([SCAP]ANOVA)[R] there was no difference in the tension at failure between expired and non-expired sutures with suture packet as a covariate. No suture untied when knotted with expired suture. CONCLUSIONS: Under laboratory conditions, expired chromic and polydioxanone sutures broke at lower tensile strength than non-expired sutures of the same material.

In vitro bursting pressures of jejunal enterotomy closures in llamas.

OBJECTIVE: To evaluate closure strength (in vitro bursting pressure) of jejunal enterotomies in llamas. STUDY DESIGN: In vitro experimental study. SAMPLE POPULATION: Jejunal specimens (n=72) from 6 llamas. METHODS: Differences in bursting pressures and luminal diameters were compared between 2 layer enterotomy closures with an initial full thickness simple continuous pattern oversewn with either a continuous Lembert or Cushing suture pattern using 3 sizes (2-0, 3-0, 4-0) of polyglactin 910 and polydioxanone. RESULTS: Bursting pressures were significantly higher for enterotomies closed with polydioxanone than polyglactin 910, independent of suture size, but there was no difference between Lembert and Cushing oversew patterns. Use of a Lembert pattern reduced intestinal diameter more than a Cushing pattern regardless of suture material or size. CONCLUSIONS: Although polydioxanone resisted higher bursting pressures than polyglactin 910, both suture materials should be considered satisfactory for jejunal enterotomy closure in llamas based on typical intraluminal pressures expected in clinical patients. The optimal oversew pattern may be continuous Cushing to maximize the luminal diameter in small intestinal enterotomy closures. CLINICAL RELEVANCE: In vitro bursting pressures may help to predict which enterotomy sites would leak post-operatively, although further studies are necessary to determine the outcome in clinical patients.

[Operative standardization in randomized controlled surgical trials. Meeting of the INSECT trial]. / Operative Standardisierung bei randomisiert kontrollierten Studien in der Chirurgie. Studientreffen der INSECT-Studie.

BACKGROUND: INSECT is an internationally registered, three-armed, multicentre, intraoperatively randomised model trial of the Study Centre of the German Surgical Society. The interventions being compared are running suture technique with slowly absorbable monofilament suture material (PDS vs MonoPlus) and interrupted technique with a braided, rapidly absorbable suture material (Vicryl). The primary endpoint is the rate of incisional hernias 1 year postoperatively. MATERIAL AND METHODS: A total of 25 surgeons from 24 different institutions at all levels of care evaluated the theoretical and practical sessions of the surgical investigator meeting using 25 criteria, including course organisation, content, and speaker evaluation, and a categorical grading system from 1 (very good) to 6 (insufficient). RESULTS: Distribution of the 625 grades was: very good (1) n=367, good (2) n=207, satisfactory (3) n=39, adequate (4) n=2, and "No statement" n=10. The average score for the investigator meeting was 1.5. CONCLUSION: The participants felt they were successfully prepared theoretically and practically for trial interventions and conduct by attending the meeting. Clear explanation of the measures for treatment equivalence before and during trials is mandatory in randomised controlled surgical trials.

An in vitro biomechanical comparison of the breaking strength and stiffness of polydioxanone (sizes 2, 7) and polyglactin 910 (sizes 3, 6) in the equine linea alba.

OBJECTIVE: To determine failure strength, stiffness, and failure mode of 4 suture materials in equine linea alba. STUDY DESIGN: Randomized complete block design. SAMPLE POPULATION: Linea albas collected from 12 adult horses (mean weight, 475 kg; mean age, 10 years). METHODS: The ventral abdominal fascia, including the linea alba, was collected and bisected along the linea alba into right and left halves. Each half was divided into four, 5-cm sections extending from the umbilicus cranially, and randomly assigned to 1 of 4 suture materials: 2 polydioxanone (2 PD), 3 polyglactin 910 (3 PG), 6 polyglactin 910 (6 PG), and 7 polydioxanone (7 PD). A single cycle to failure test was performed on each specimen at a distraction rate of 100 mm/min. Differences in failure strength and stiffness for the materials were evaluated using a mixed linear model with significance set at P<.05. RESULTS: In 94 of 96 test sections, constructs failed by suture failure. There were significant differences in failure strength (P<.0001) and stiffness (P<.001) among the suture/tissue constructs. 7 PD had the highest breaking strength (316.8 N) followed by 6 PG (281.3 N), 3 PG (229.9 N), and 2 PD (193.0 N). Six PG had the largest stiffness (14 N/mm) followed by 3 PG (12.7 N/mm), 7 PD (10.1 N/mm), and 2 PD (7.2 N/mm). Suture breaking strength and stiffness were not affected by linea or fascia thickness, individual horse, half of the linea alba, or abdominal wall position. Eighty-five (90.4%) suture loops failed adjacent the knot. CONCLUSIONS: When tested in single cycle to failure, suture material was more likely to fail than the linea alba. Larger suture materials had higher breaking strengths than smaller suture materials and stiffness was also affected by suture material and size. CLINICAL RELEVANCE: Given its high initial breaking strength and its relatively longer in vivo strength retention, 7 PD seems an appropriate choice of suture material for closure of the equine linea alba when maximal short-term failure strength is desired.

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.