#419 Facet Arthroplasty Utilizing the ACADIA® Facet Replacement System: Preliminary IDE Outcomes at Two and Three Years Postoperative

General Session: Lumbar Therapies Motion Preservation

Presented by: A. D. Tahernia


A.D. Tahernia (1)
J.J. Regan (2)
T. Briggs (3)
M.P. Lorio (4)
J. Youssef (5)
S. Webb (6)
D. Whiting (7)
K. Baker (8)
J. Myer (8)

(1) Desert Orthopedic Center, Rancho Mirage, CA, USA
(2) DISC, Beverly Hills, CA, USA
(3) Springfield Neurological and Spine Institute, Springfield, MO, USA
(4) Neuro-Spine Solutions, Bristol, TN, USA
(5) Durango Orthopedic Associates/Spine Colorado, Durango, CO, USA
(6) Florida Spine Institute, Clearwater, FL, USA
(7) Allegheny General Hospital, Pittsburgh, PA, USA
(8) Globus Medical, Inc., Audubon, PA, USA


Purpose: An Investigational Device Exemption (IDE) study is currently underway to evaluate the safety and efficacy of the ACADIA® Facet Replacement System. Preliminary outcomes at two and three year post-operative are presented for patients randomized to ACADIA® or an instrumented posterolateral fusion (PLF).

Methods: A prospective, randomized pivotal IDE study of the ACADIA® Facet Replacement System (Globus Medical, Audubon, PA) is being conducted at up to thirty sites across the U.S. Enrolled patients are randomized 2:1 to either the investigational ACADIA® device or the control PLF, with the option for two non-randomized patients as training cases at each site. Candidates for study participation must have degenerative lateral, lateral recess and/or central canal stenosis at a single level from L3 to S1 that requires decompression and facetectomy, and failed to improve with at least six cumulative months of conservative treatment. Outcome measures and radiographic evaluations are collected pre-operatively and at 6 weeks, 3, 6, 12 and 24 months and annually thereafter. Individual success criteria include: improvement in ZCQ score by a minimum decrease of 0.5 versus baseline for both Symptom Severity (SS) and Physical Function (PF) scores; no subsequent surgical intervention at the level of treatment; maintenance or improvement in neurological status at 24 months; and no serious device-related adverse events. Outcomes are presented for 161 patients randomized and treated in the study: 109 patients treated with ACADIA® and 52 patients receiving PLF.

Results: Demographics are similar between the two randomized groups. Both cohorts demonstrate post-operative improvement in mean ZCQ and VAS scores. For ACADIA® patients, the average ZCQ SS score improved from 3.6 pre-op to 1.9 at 24 months and 2.0 at 36 months, compared to 3.7 pre-op to 2.1 at 24 months and 1.9 at 36 months for PLF patients. ZCQ PF scores improved from 2.8 pre-op to 1.6 at 24 months and 1.6 at 36 months for ACADIA®, versus 2.8 pre-op to 1.8 at 24 months and 1.5 at 36 months for PLF. A decrease in VAS back pain scores was observed in the investigational and control patients; scores were 69 at pre-op, 20 at 24 months and 24 at 36 months and 67 at pre-op, 25 at 24 months and 22 at 36 months, respectively. Mean VAS left leg pain scores decreased from 61 at pre-op to 13 at 24 months and 15 at 36 months for ACADIA® versus 54 at pre-op to 22 at 24 months and 15 at 36 months for control patients. Mean VAS right leg pain scores improved from 56 pre-op to 14 at 24 months and 15 at 36 months for ACADIA® and from 57 pre-op to 12 at 24 months and 16 at 36 months for PLF patients. Subsequent surgical intervention has occurred in 7.0% of patients treated with ACADIA® and 7.5% of patients treated with PLF.

Conclusion: Current results suggest the ACADIA® Facet Replacement System may be an effective treatment for lumbar spinal stenosis as an alternative to an instrumented posterolateral fusion. Continued follow-up is required to determine the long term safety and efficacy of the investigational ACADIA® device.