Dataset Information

Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation.

ABSTRACT:

Objective

To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications.

Design

Experimental study.

Methods

The force to disinsert flanged polypropylene suture from human cadaveric sclera was assessed using a tensile testing machine and compared to the breaking strengths of 9-0 and 10-0 polypropylene. The effects of modifying suture gauge (5-0, 6-0, 7-0, or 8-0), amount of suture cauterized (0.5 or 1.0 mm), and sclerotomy size (27, 30, 32, 33 gauge) were investigated. Belt-loop intrascleral fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge needles, respectively, was performed in 4 patients. Main outcome measures were flanged suture disinsertion forces in cadaveric sclera.

Results

The average force to disinsert a flange created by melting 1.0 mm of 5-0, 6-0, 7-0, and 8-0 polypropylene suture from human cadaveric sclera via 27, 30, 32, and 33 gauge needle sclerotomies was 3.0 ± 0.5 N, 2.1 ± 0.3 N, 0.9 ± 0.2 N, and 0.4 ± 0.1 N, respectively. The disinsertion forces for flanges formed by melting 0.5 mm of the same gauges were 72%-79% lower (P < .001). In comparison, the breaking strengths of 9-0 and 10-0 polypropylene were 0.91 ± 0.4 N and 0.52 ± 0.03 N. Belt-loop fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge sclerotomies demonstrated good outcomes at 6 months.

Conclusions

The flanged belt-loop technique is a biomechanically sound method of scleral fixation using 1.0 mm flanges of 5-0 to 7-0 polypropylene paired with 27, 30, and 32 gauge sclerotomies. In contrast, 8-0 polypropylene and 0.5 mm flanges of any suture gauge will likely be unstable with this technique.

SUBMITTER: Yuan A

PROVIDER: S-EPMC10560604 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature

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Publications

Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation.

Yuan Amy A Ma Kevin K Sharifi Sina S Pineda Roberto R

American journal of ophthalmology 20210501

<h4>Objective</h4>To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications.<h4>Design</h4>Experimental study.<h4>Methods</h4>The force to disinsert flanged polypropylene suture from human cadaveric sclera was assessed using a tensile testing machine and compared to the breaking strengths of 9-0 and 10-0 polypropylene. The effects of modifying suture gauge (5-0, 6-0, 7-0, or 8-0), amount of suture cauteri ...[more]

PMID: 33945819

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Project description:BackgroundThis report serves to describe the use of a novel adjustable single 8-0 polypropylene suture for scleral fixation without conjunctival dissection, and to describe related clinical outcomes associated with this approach.MethodsIn this study, we retrospectively reviewed 28 eyes from 27 patients that underwent scleral fixation of the intraocular lens (IOL) without conjunctival dissection using an adjustable single 8-0 polypropylene suture at the Beijing Tongren Eye Center between April 2018 and April 2019. For this surgical approach, a 23-gauge infusion cannula was set, after which two Hoffmann scleral pockets were created. Next, 8-0 polypropylene sutures were inserted into the eye guided by 10-0 polypropylene sutures of a long straight needle. The 8-0 suture was then used to fix the haptic IOs. Finally, these 8-0 polypropylene sutures were removed from the scleral pockets, and knots were tightened with the adjustable single suture. Primary outcomes included visual acuity and postoperative complication incidence.ResultsFor this study, outcomes for 28 eyes from 27 patients (9 female, 18 male) were assessed. Patients had a mean age of 54 ± 15.11 years-old and were followed for an average of 10.18 ± 2.76 months postoperatively. Uncorrected visual acuity in these patients improved significantly from a preoperative value of 1.269 ± 0.464 logMAR to a 3-month postoperative value of 0.409 ± 0.413 logMAR (p = 0.000). The majority of postoperative complications in these patients were temporary and self-limiting, including corneal edema (35.71%), hypotony (14.29%), elevated intraocular pressure (28.58%), and mild hyphema (7.14%). No evidence of exposure or erosion of the trimmed suture end was detected in any patients. An ultrasound biomicroscope was able to readily detect the IOL and all sutures, and IOLs were found to be well-centered without any dislocation, tilting, or subluxation upon follow-up.ConclusionsAn adjustable single 8-0 polypropylene suture can reliably and effectively be used for scleral fixation without conjunctival dissection for the treatment of patients with aphakia or inadequate posterior capsule support. The novel procedure described herein may therefore be an effective means of minimizing the risk of suture-related complications in patients undergoing scleral-fixated IOL implantation.Trial registrationRetrospective case series study, not applicable. NCT04476264 .

Project description:BackgroundExpandable screws have greater pullout strength than conventional screws. The purpose of this study was to compare the biomechanical stability provided by a new built-in expandable anterior spinal fixation system with that of 2 commonly used anterior fixation systems, the Z-Plate and the Kaneda, in a porcine partial vertebral corpectomy model.MethodsEighteen porcine thoracolumbar spine specimens were randomly divided into 3 groups of 6 each. A vertebral wedge osteotomy was performed by removing the anterior 2/3 of the L1 vertebral body and the T15/L1 disc. Vertebrae were fixed with the Z-Plate, Kaneda, or expandable fixation system. The 3-dimensional spinal range of motion (ROM) of specimens in the intact state (prior to osteotomy), injured state (after osteotomy), and after internal fixation were recorded. The pullout strength and maximum torque of common anterior screws, the expandable anterior fixation screw unexpanded, and the expandable anterior fixation screw expanded was tested.ResultsAfter internal fixation, the expandable device and Z-plate system exhibited higher left bending motion than the Kaneda system (5.50° and 5.37° vs. 5.04, p = 0.001 and 0.008, respectively), and the Z-plate and Kaneda groups had significantly higher left axial and right axial rotation ROM as compared to the expandable device group (left axial rotation: 5.23° and 5.02° vs. 4.53°; right axial rotation: 5.23° and 5.08° vs. 4.49°). The maximum insertion torque of the expandable device was significantly greater than of a common screw (5.10 vs. 3.75 Ns). The maximum pullout force of the expandable device expanded was significantly higher than that of the common screw and the expandable device unexpanded (3,035.48 N vs. 1,827.38 N and 2,333.49 N).ConclusionsThe built-in anterior fixation system provides better axial rotational stability as compared to the other 2 systems, and greater maximum torque and pullout strength than a common fixation screw.

Dataset Information

Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation.

Objective

Design

Methods

Results

Conclusions

Publications

Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation.

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