Pedicle screw augmentation with polyethylene tape: a biomechanical study in the osteoporotic thoracolumbar spine.
METHODS
Biomechanical study using human thoracolumbar spines.


OBJECTIVE
To assess the strength of fixation of pedicle screws augmented with Nesplon tape applied sublaminar or applied subpars.


BACKGROUND
There are no reports on the biomechanical assessment of Nesplon tape used for pedicle screw augmentation.


METHODS
Experiment 1: pedicle screws were inserted into bilateral pedicles as follows: (1) pedicle screw alone connected to a rod (PS alone), (2) pedicle screw augmented with Nesplon tape applied sublaminar, connected to a rod [pedicle screw applied sublaminar (PSSL)], and (3) pedicle screw augmented with tape applied subpars, connected to a rod [pedicle screw applied subpars (PSSP)]. The rods were pulled and pushed until the pedicle screw was loose. Experiment 2: 6 thoracolumbar spines were biomechanically tested as follows: axial compression, flexion, extension, left and right lateral bending, and left and right axial rotation. This sequence was applied to: (1) the intact spine; (2) the spine made unstable; (3) the spine fixed by pedicle screws and rods (PS alone); (4) the same as 3, but with the pedicle screws augmented using Nesplon tape applied sublaminar (PSSL); and (5) the same as 3, but with pedicle screws augmented using tape applied subpars (PSSP). From the load-deformation curves, stiffness values were calculated.


RESULTS
Experiment 1: the pedicle screws augmented by sublaminar or subpars tape (PSSL or PSSP) showed significantly greater fixation strength compared with those pedicles that were not augmented by tape (PS alone). Experiment 2: a pedicle screw/rod construct augmented by tape provided a stiffer construct than the same construct without augmentation.


CONCLUSIONS
Pedicle screws that are inserted into the osteoporotic thoracolumbar spine and augmented by Nesplon tape applied sublaminar or subpars provide firmer fixation of the screws and a stiffer pedicle screw/rod construct than the same construct without augmentation by tape.
Hamasaki
Takahiko
T
Department of Orthopaedic Surgery, Emory Spine Center, Atlanta, GA 30329, USA.
Tanaka
Nobuhiro
N
Kim
JinHwan
J
Okada
Motohiro
M
Ochi
Mitsuo
M
Hutton
William C
WC
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology; D001863:Bone Screws / Q000592:standards*; D002102:Cadaver; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D009068:Movement / Q000502:physiology; D010024:Osteoporosis / Q000473:pathology* / Q000503:physiopathology*; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control; D019919:Prosthesis Implantation / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D013131:Spine / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D053832:Surgical Tape / Q000592:standards*; D013904:Thoracic Vertebrae / Q000473:pathology / Q000503:physiopathology / Q000601:surgery