Balloon Kyphoplasty and a Deployable Cement Containment Device Kyphoplasty: Is there a Difference in Stabilization of Vertebral Compressive Fractures?

Presented at SMISS Annual Forum 2014
By Eeric Truumees MD
With Brandon Bucklen PhD, Noelle Klocke MS, Jonathan Harris MS, Suresh Chinthakunta MS,

Disclosures: Eeric Truumees MD A; Pfizer, Stryker. F; Stryker. Brandon Bucklen PhD E; Globus Medical Inc., Noelle Klocke MS E; Globus Medical, Inc., Jonathan Harris MS E; Globus Medical, Inc., Suresh Chinthakunta MS E; Globus Medical, Inc.,

Introduction:
Percutaneous balloon kyphoplasty (BK) following a vertebral compression fracture aims to restore anterior vertebral height while stabilizing bone fragments. After insertion of a balloon to compress the fragments toward the walls, the centralized cavity is filled using bone cement. However, there is a risk for acute cement extravasation. A deployable, compliant implant has been used in conjunction with BK to create a physical cement barrier.

Aims/Objectives:
Assess the fracture stabilization, via biomechanical strength, of a traditional unipedicular balloon kyphoplasty (BK) as compared to a compliant, cement-containing (CCC) device. The authors hypothesized that, despite the design differences, fracture stabilization results would be equivalent.

Methods:
Cadaveric vertebral bodies (n=12, T11-L4) were assigned to receive either traditional balloon kyphoplasty (BK, Algea Therapies, Audubon, PA) or a kyphoplasty using a deployable, compliant cement-containing device kyphoplasty (CCC, Algea Therapies, Audubon, PA). Posterior elements (except pedicles) were removed, and endplate impressions (Bondo, Bondo Corp, Atlanta, GA) were made. Metal phantoms served as measurement references for consistent fluoroscopic alignment and scaling. Anteriorly-placed burst fractures were created (axial compression: 5mm/min until intact anterior height reduced by 40%) using a MTS 858 Mini Bionix (MTS Corporation, Minneapolis, MN). Under continuous, physiologically-based axial loading (111N), a bone tamp was placed and lateral fluoroscopic images captured each procedural phase: after fracture creation, balloon inflation (4cc of saline), and after cement injection. After curing, the augmented bodies were compressed axially, and compared to the initial load-to-failure values. Anterior height measurements and axial cement placement measurements were made using ImageJ (NIH, USA) from fluoroscopic images, and compared using a one-way ANOVA with Tukey’s post hoc (p<0.05).

Results:
Normalized anterior height of the vertebral bodies were statistically equivalent between BK and CCC during each procedural phase (p>0.05). Normalized load-to-failure of the augmented BK group was 235.1±48.2%, and was equivalent to the CCC 166.8±105.7%. Cement placement in the anterior-posterior direction was significantly more anterior in the BK group (13.6±6.0% A-P depth) than the CCC group (9.5±6.8%), yet were statistically the same in the medial-lateral direction (BK: 9.2±4.2% vs. CCC: 9.9±10.3%).

Conclusions:
Cement containing implants did not negatively affect anterior height maintenance nor load-to-failure as compared to traditional balloon kyphoplasty. The centralized placement as shown in the axial fluoroscopic measurements demonstrated that the implant could reduce both the acute and gross cement extravasation risks that are associated with traditional balloon kyphoplasty, thus making it a slightly more attractive cement augmentation methodology for vertebral compressive fractures.