Effect of knot location on the biomechanical strength and gapping characteristics of ex vivo canine gastrocnemius tenorrhaphy constructs

OBJECTIVE To evaluate the effect of knot location on the biomechanical strength and gapping characteristics of ex vivo canine gastrocnemius tenorrhaphy constructs. SAMPLE 36 cadaveric gastrocnemius tendons from 18 adult dogs. PROCEDURES Tendons were randomly assigned to 3 groups (12 tendons/group) and sharply transected and repaired by means of a core locking-loop suture with the knot at 1 of 3 locations (exposed on the external surface of the tendon, buried just underneath the external surface of the tendon, or buried internally between the apposed tendon ends). All repairs were performed with size-0 polypropylene suture. All constructs underwent a single load-to-failure test. Yield, failure, and peak forces, mode of failure, and forces required for 1- and 3-mm gap formation were compared among the 3 knot-location groups. RESULTS Mean yield, failure, and peak forces and mean forces required for 1- and 3-mm gap formation did not differ significantly among the 3 groups. The mode of failure also did not differ significantly among the 3 groups, and the majority (33/36 [92%]) of constructs failed owing to the suture pulling through the tendinous substance. CONCLUSIONS AND CLINICAL RELEVANCE Final knot location did not significantly affect the biomechanical strength and gapping characteristics of canine gastrocnemius tenorrhaphy constructs. Therefore, all 3 evaluated knot locations may be acceptable for tendon repair in dogs. In vivo studies are necessary to further elucidate the effect of knot location in suture patterns commonly used for tenorrhaphy on tendinous healing and collagenous remodeling at the repair site.

Cadaveric Evaluation of Load to Failure in Canine Gingiva Apposed With Varied Suture Patterns Using Poliglecaprone 25

The purpose of the study was to determine the effect of suture pattern and repair length on the load to failure in an ex vivo canine gingival model. Healthy mandibular gingiva and mucosa were harvested from fresh cadavers euthanized for purposes unrelated to the study. Samples were randomly assigned by length and pattern. Lingual and buccal free gingival margins were apposed using a simple interrupted (SI), cruciate (XT), simple continuous (SC), or unidirectional knotless continuous barbed suture (SF) closure technique with USP 4-0 poliglecaprone 25i, ii applied over 2 lengths (3 cm and 6 cm). A custom template was used to ensure uniform suture bite application. Surgical time was recorded. Using a soft tissue mechanical testing frame, samples were tensioned to failure. Testing was video recorded and reviewed in conjunction with the tension trace data for tension at initial failure (Tfail) and maximum tension sustained (Tmax). Two factor ANOVA by length and pattern was performed followed by individual one way T-tests. Statistically significant findings were XT-SC-SF patterns were quicker to perform than SI. SF was more likely to fail by suture breakage than tissue tearing, and SF withstood less tension at the 3 cm length than SI-XT-SC. No significant difference was detected in Tmax or Tfail between SI and SC or XT. The study demonstrates that SC and XT are comparable to SI in tension resistance and faster to perform suggesting that SC and XT could replace SI for extraction site closure although further in vivo testing is required.

Noise-induced scaling in skull suture interdigitation

Sutures, the thin, soft tissue between skull bones, serve as the major craniofacial growth centers during postnatal development. In a newborn skull, the sutures are straight; however, as the skull develops, the sutures wind dynamically to form an interdigitation pattern. Moreover, the final winding pattern had been shown to have fractal characteristics. Although various molecules involved in suture development have been identified, the mechanism underlying the pattern formation remains unknown. In a previous study, we reproduced the formation of the interdigitation pattern in a mathematical model combining an interface equation and a convolution kernel. However, the generated pattern had a specific characteristic length, and the model was unable to produce a fractal structure with the model. In the present study, we focused on the anterior part of the sagittal suture and formulated a new mathematical model with time–space-dependent noise that was able to generate the fractal structure. We reduced our previous model to represent the linear dynamics of the centerline of the suture tissue and included a time–space-dependent noise term. We showed theoretically that the final pattern from the model follows a scaling law due to the scaling of the dispersion relation in the full model, which we confirmed numerically. Furthermore, we observed experimentally that stochastic fluctuation of the osteogenic signal exists in the developing skull, and found that actual suture patterns followed a scaling law similar to that of the theoretical prediction.

A comparison of the mechanical strength of three different suture techniques for intercostal thoracotomy closure - ex vivo study

The transcostal closure technique of intercostal thoracotomy closure appears to be associated with less pain in the first 24 hours and could be an alternative to the standard circumcostal technique. The goal of this study was to compare the ex vivo biomechanical properties of three suture techniques for intercostal thoracotomy closure. Samples of porcine ribs were used for the research. A 10 cm incision was made in the intercostal space in each sample. The techniques compared were: simple circumcostal interrupted suturing, continuous circumcostal suturing, and interrupted transcostal suturing. During the testing in the machine, suture rupture or rib cracking occurred. If rib cracking occurred first, the testing was continued until the suture broke as well. In the first group, rib fracture occurrence was 60% and suture rupture was 40%. In the second group, rib fracture occurrence was 55%, while 45% of the samples failed by suture rupture. In the third group, rib fracture occurrence was 70%, while suture rupture was 30%. These data did not differ significantly between groups (P>0.05). Continuous circumcostal suturing took the least amount of time, and the most time-consuming technique was interrupted transcostal suturing. Simple circumcostal suturing used most material, and the least amount of material was used with continuous circumcostal suturing. The conclusion of this paper is that the continuous pattern suture has the same mechanical strength as the other two suture patterns, but it consumes the least time and material. Therefore, from a mechanical standpoint, we advise the use of continuous circumcostal suture for intercostal thoracotomy closure.

Suture pattern does not influence outcomes of endoscopic sleeve gastroplasty in obese patients

Background and study aims ESG is an effective and safe medium-term procedure for obesity treatment. A variety of suture patterns have been reported. We aimed to compare whether there are differences in efficacy depending on suture pattern used. Patients and methods Retrospective and comparative review of 5 years of prospectively collected data, including consecutive obese patients undergoing ESG at two collaborative centers. Primary outcomes included weight loss (mainly % total body weight loss [TBWL] and % exces weight loss [EWL]) at 12 months and safety profile. We compared them according to three suture patterns (transverse bilinear [TBp], longitudinal [Lp] and transverse monolinear [TMp]), and number of sutures (4 – 7) and stitches (< 25, 25 to 30 and > 30) applied. Evolution of major obesity-associated morbidities (hypertension, dyslipidemia, Type 2 diabetes mellitus (T2DM), sleep obstructive apnea syndrome, and arthropathy) were also described. Results 88 patients (mean age 46.1±12.3 years, 69.3 % female) underwent ESG. Mean body mass index (BMI) at baseline was 39.40 ± 4.69 kg/m². At 1 year, %TBWL was 17.36 ± 6.09 % (%EWL 46.41±20.6 %) with TBWL > 10 % in 95.5 % of patients (EWL > 25 % in 94.3 % of patients). According to pattern, there were no differences in %TBWL but there were in %EWL (43.7 ± 20.4 %, 59.8 ± 18.9 % and 45.4 ± 14.9 % in TBp, Lp and TMp patterns, respectively) (P = 0.034). No differences were found related to number of sutures (mean 5.2 ± 0.73, r = 4 – 7) or stitches (mean 27.4 ± 6.50, r = 18 – 50) applied. Forty-three of 72 (59.7 %) major comorbidities were resolved. No serious adverse events were observed with any pattern. Conclusions ESG is an effective procedure at 12-month follow-up for weight loss and comorbidity resolution. All three analyzed patterns are safe and effective without differences in %TBWL, but there was a slight increase in %EWL in Lp, regardless of the number of sutures or stitches applied.