Evaluation of Two Novel Integrated Stand-Alone Spacer Designs Compared with Anterior and Anterior-Posterior Single-Level Lumbar Fusion Techniques: An In Vitro Biomechanical Investigation.
10.4184/asj.2017.11.6.854
- Author:
Craig A KUHNS
1
;
Jonathan A HARRIS
;
Mir M HUSSAIN
;
Aditya MUZUMDAR
;
Brandon S BUCKLEN
;
Saif KHALIL
Author Information
1. Austin Spine Center, Lakeway Regional Hospital, Lakeway, TX, USA.
- Publication Type:Original Article
- Keywords:
Intervertebral disc degeneration;
Lumbar region;
Range of motion;
Equipment design
- MeSH:
Cadaver;
Diskectomy;
Equipment Design;
In Vitro Techniques*;
Intervertebral Disc Degeneration;
Lumbosacral Region;
Pedicle Screws;
Range of Motion, Articular;
Spine
- From:Asian Spine Journal
2017;11(6):854-862
- CountryRepublic of Korea
- Language:English
-
Abstract:
STUDY DESIGN: In vitro biomechanical investigation. PURPOSE: To compare the biomechanics of integrated three-screw and four-screw anterior interbody spacer devices and traditional techniques for treatment of degenerative disc disease. OVERVIEW OF LITERATURE: Biomechanical literature describes investigations of operative techniques and integrated devices with four dual-stacked, diverging interbody screws; four alternating, converging screws through a polyether-ether-ketone (PEEK) spacer; and four converging screws threaded within the PEEK spacer. Conflicting reports on the stability of stand-alone devices and the influence of device design on biomechanics warrant investigation. METHODS: Fourteen cadaveric lumbar spines were divided randomly into two equal groups (n=7). Each spine was tested intact, after discectomy (injured), and with PEEK interbody spacer alone (S), anterior lumbar plate and spacer (AP+S), bilateral pedicle screws and spacer (BPS+S), circumferential fixation with spacer and anterior lumbar plate supplemented with BPS, and three-screw (SA3s) or four-screw (SA4s) integrated spacers. Constructs were tested in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Researchers performed one-way analysis of variance and independent t-testing (p≤0.05). RESULTS: Instrumented constructs showed significantly decreased motion compared with intact except the spacer-alone construct in FE and AR (p≤0.05). SA3s showed significantly decreased range of motion (ROM) compared with AP+S in LB (p≤0.05) and comparable ROM in FE and AR. The three-screw design increased stability in FE and LB with no significant differences between integrated spacers or between integrated spacers and BPS+S in all loading modes. CONCLUSIONS: Integrated spacers provided fixation statistically equivalent to traditional techniques. Comparison of three-screw and four-screw integrated anterior lumbar interbody fusion spacers revealed no significant differences, but the longer, larger-diameter interbody spacer with three-screw design increased stabilization in FE and LB; the diverging four-screw design showed marginal improvement during AR.
