Radiopaque UHMWPE sublaminar cables for spinal deformity correction: Preclinical mechanical and radiopacifier leaching assessment

Abstract

Polymeric sublaminar cables have a number of advantages over metal cables in the field of spinal deformity surgery, with decreased risk of neurological injury and potential for higher correction forces as the two most predominant. However, currently available polymer cables are radiolucent, precluding postoperative radiological assessment of instrumentation stability and integrity. This study provides a preclinical assessment of a woven UHMWPE cable made with radiopaque UHMWPE fibers. Our primary goal was to determine if the addition of a radiopacifier negatively affects the mechanical properties of UHMWPE woven cables. Tensile mechanical properties were determined and compared to suitable controls. Radiopacity was evaluated and radiopacifier leaching was assessed in vitro and in vivo. Finally, in vivo bismuth organ content was quantified after a 24-week implantation period in sheep. Results show that the mechanical properties of woven UHMWPE cables were not deleteriously affected by the addition of homogenously dispersed bismuth oxide particles within each fiber. Limited amounts of bismuth oxide were released in vitro, well below the toxicological threshold. Tissue concentrations lower than generally accepted therapeutic dosages for use against gastrointestinal disorders, well below toxic levels, were discovered in vivo. These results substantiate controlled clinical introduction of these radiopaque UHMWPE cables. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 771-779, 2018.

Banding with lesser trochanter fragment using nonabsorbable tape in trochanteric femoral fractures

“…The Nesplon tape ® is a UHMWPE fiber tape with properties of high strength and flexibility [ 28 , 29 ]. UHMWPE tapes have already been employed in several surgical fields such as spinal fusion and hip arthroplasty [ 30 , 31 ]. We used a dedicated tensioner device (Alfresa Pharma Co., Ltd., Osaka, Japan) to apply the initial tension of 200 N to the fiber tape ( Figure 2 ).…”

Biomechanical Evaluation of Semi-rigid Junctional Fixation Using a Novel Cable Anchor System to Prevent Proximal Junctional Failure in Adult Spinal Deformity Surgery

“…Care was taken to keep ligamentous tissue as much intact as possible. After fixation of the spinal rods to the pedicle screws, UHMWPE tapes (Dyneema Purity® Radiopaque fibers; DSM Biomedical, Geleen, the Netherlands) were knotted, pre-tensioned to 500 N, and secured with an additional 6 reverse halve-hitches 18 …”

Ultra–high-molecular-weight polyethylene sublaminar tape as semirigid fixation or pedicle screw augmentation to prevent failure in long-segment spine surgery: an ex vivo biomechanical study

“…19 The UHMWPE ST is a 4-mm-wide radiopaque woven tape made with Dyneema Purity Radiopaque fibers. 11 After a first half-hitch, the knot was tensioned up to 500 N with a custom-made device. Finally, the knots were secured with 6 additional reversed half-hitches on alternating posts.…”

“…Isotropic elastic properties were considered for PS material (E = 110 GPa, ν = 0.3). The ST was modeled as an isotropic elastic material (UHMWPE: E = 5 GPa, ν = 0.3 11 ), whereas the bilateral spinal rods were modeled as rigid connector elements. Linear elastic simulations were carried out and a load of 1000 N was applied to the rods bilaterally at a distance (d load ) of 25 mm from the rotation point.…”

“…Furthermore, ultra-high-molecular-weight polyethylene (UHMWPE) ST has a substantially higher fatigue strength in comparison to metal sublaminar wires. 11 The goal of this ex vivo biomechanical study was to assess the instantaneous failure characteristics of different spinal fixation methods by using human cadaveric vertebrae in a flexion-bending setup to represent loads occurring at the ends of a long-segment construct. We hypothesize that sublaminar fixation possesses a lower fixation stiffness and an equal or higher pullout strength compared to PSs.…”