Expandable Anterior Lumbar Interbody Fusion Device Associated with More Height and Intervertebral Angle Versus Static Spacer: A Comparative Investigation of Devices with Integrated Fixation

Thursday, June 1, 2023

8:30 AM – 6:15 PM

Location: Salons 7-8

Co-Author(s)

WM

William L. Mills, Sr., MD

Myrtle Beach, South Carolina, United States

Co-Author(s)

WM

William L. Mills, Jr., MD

University of South Carolina School of Medicine, United States
AR

Amy Rosenthal, MSc

Clinical Research Project Manager
Globus Medical Inc.
Audubon, Pennsylvania, United States
IM

Isabella R. Mager, BS

Associate Clinical Research Project Manager
Globus Medical, INC.
Audubon, Pennsylvania, United States

Presenting Author (Person doing the Podium Present(s)

BB

Brandon S. Bucklen, PhD, PhD

Director of Research
Globus Medical Inc
Audubon, Pennsylvania, United States

View E-Poster

Submitter(s)

IM

Isabella R. Mager, BS

Associate Clinical Research Project Manager
Globus Medical, INC.
Audubon, Pennsylvania, United States

Disclosure(s):

Brandon S. Bucklen, PhD, PhD: No relevant disclosure to display

Introduction: Traditionally, the Anterior Lumbar Interbody Fusion (ALIF) technique utilizes interbody spacers of fixed height, known as static spacers. Expandable technology was designed to minimize the inherent issues associated with static spacers such as forceful impaction. This is achieved through vertical expansion in situ. Modern ALIF devices include low-profile integrated plates and fixation utilizing screws or blades. Studies comparing static and expandable interbody spacers are limited but show promising results.

AIMS/

Objectives: The goal of this study is to compare the radiographic outcomes of patients treated with expandable spacers (utilizing screws for integrated fixation) and static spacers (utilizing integrated blades for fixation) at 1 year postoperatively. The radiographic outcomes are lumbar lordosis, segmental lordosis, intervertebral angle, and anterior, posterior, and foramen heights.

Methods: This was a retrospective, IRB-exempt chart review of 59 patients diagnosed with DDD who underwent ALIF using static or expandable spacers. There were 31 patients treated with static spacers with integrated anti-migratory blades (SSIB) and 28 with expandable spacers with integrated fixation (ESIF). All patients had data available for evaluation at 12 months postoperative. The data was further split by operative level. Statistical results were significant if P < .05.

Results: At the L4/5 surgical level, SSIB and ESIF were statistically different at 1 year when compared to pre-operative for the anterior height (SSIB: 16.9mm vs. 13.9mm, p<.05; ESIF: 21.1mm vs. 15.8mm, p<.001). ESIF was significant at the 1-year follow-up for the intervertebral angle (15.6° vs. 9.7°, p<.001) and posterior height (9.4mm vs. 7.5mm, p<.05). When the interbody groups were compared at the L4/5 level the intervertebral angle (15.6° vs. 9.3°, p<.001) and anterior height (21.1mm vs. 16.9mm, p=.002) were statistically higher for ESIF.
At the L5/S1 surgical level, SSIB and ESIF were statistically different at 1 year when compared to pre-operative for the anterior (SSIB: 20.6mm vs. 13.1mm, p< 0.001; ESIF: 23.6mm vs. 16.7mm, p<.001) and posterior heights (SSIB: 10.6mm vs. 7.5mm, p<.001; ESIF: 10.1mm vs. 6.4mm, p<.001). However, only SSIB was significantly greater at the 1-year follow-up for the foramen height (20.0mm vs. 17.7mm, p<.05). When the two interbody groups were compared at the L5/S1 level the intervertebral angle (18.8° vs. 14.1°, p<.001) and anterior heights (23.6mm vs. 20.6mm, p=.002) were statistically higher for ESIF.
At both surgical levels, the global lordosis (SSIB: 55.1° vs. 51.3°; ESIF: 50.1° vs. 49.2°) and foramen heights (SSIB: 22.0mm vs. 20.1mm; ESIF: 22.7mm vs. 20.4mm) were greater at 1 year than pre-operatively for both cohorts. At L5/S1, both spacers had a larger segmental lordosis (SSIB: 20.9° vs. 18.6°; ESIF: 20.6° vs. 20.1°) at 1 year versus pre-operatively. ESIF had a larger 1-year segmental lordosis at the L4/5 level (17.1° vs. 16.0°). However, none of these parameters were statistically significant.

Conclusions: ALIF devices with integrated fixation improved select radiographic parameters including intervertebral angle, and anterior and posterior heights to 1 year postoperatively. A greater degree of positive radiographic outcomes was observed for patients who underwent ALIF with expandable spacers with integrated fixation as compared to static spacers with integrated anti-migratory blades.