113 - Decompression and dynamic sagittal tether stabilization vs TLIF for degenerative spondylolisthesis. 24-month follow-up from an FDA IDE trial

Saturday, June 3, 2023

11:04 AM – 11:06 AM

Location: Salons 13-15

Presenting Author (Person doing the Podium Present(s)

TA

Todd F. Alamin, MD

California, United States

Co-Author(s)

EC

Eugene J. Carragee, MD

California, United States
SH

Serena Hu, MD

United States
RS

Rick C. Sasso, MD

Professor/Chief of Spine Surgery department of orthopaedic surgery Indiana Univ. School of Medicine
Indiana Spine Group
Carmel, Indiana, United States
HB

Hyun Bae, MD

United States
AV

Alan T. Villavicencio, MD

Boulder Neurosurgical Associates, United States
JG

Jeffrey L. Gum, MD

Adult and Pediatric Spine Surgeon
Norton Leatherman Spine
Louisville, Kentucky, United States
MP

Mick J. Perez-Cruet, MD, MS

Vice Chairman and Professor
Michigan Head and Spine Institute
Southfield, Michigan, United States
SY

S. Tim Yoon, MD, PhD

Professor
Emory University
Atlanta, Georgia, United States
William F. Lavelle, MD

Surgeon
State University of New York Upstate Medical University
Syracuse, New York, United States
KK

Kee D. Kim, MD

Chief, Spinal Neurosurgery
UC Davis
Sacramento, California, United States
MW

Michael Y. Wang, MD

Professor
University of Miami Department of Neurosurgery
Miami, Florida, United States
RB

Ravi S. Bains, MD

Chief, Regional Spine Surgery Dept.
Kaiser Permanente
Oakland, California, United States
CK

Calvin C. Kuo, MD

Attending Spine Surgeon
Kaiser Oakland Medical Center
Oakland, California, United States
HS

Harvinder S. Sandhu, MD

Surgeon
Hospital for Special Surgery
New York, New York, United States
MS

Michael P. Stauff, MD

Massachusetts, United States
DC

Dennis G. Crandall, MD

United States
SB

Sigurd Berven, MD

Professor in Residence
UC San Francisco
San Francisco, California, United States
HD

Harel Deutsch, MD

Associate Professor of Neurosurgery
Rush
Chicago, Illinois, United States
JF

Jeffrey S. Fischgrund, MD

Professor and Chairman, Department of Orthopedics
Beaumont Hospital-Royal Oak, United States
WR

W Zack Ray, MD

Missouri, United States
MM

Matthew J. Mermer, M.D., MD

Kaiser Permanente, California, United States
KS

Khalid Sethi, MD

New York, United States
AS

Adam L. Shimer, MD

United States
RD

Reginald J. Davis, MD

Biospine Institute, United States
EY

Elizabeth Yu, MD

Associate Professor
The Ohio State University Wexner Medical Center
Columbus, Ohio, United States
JC

Jens R. Chapman, MD

Washington, United States
AW

Andrew P. White, MD

Chief, Spine Division
BIDMC Orthopaedic Surgery, Harvard Medical School, United States
RG

Richard D. Guyer, MD

Spine Surgeon
Center for Disc Replacement at Texas Back Institute
Plano, Texas, United States
LF

Louis C. Fielding, MS

COO
Empirical Spine
San Carlos, California, United States
WW

William Welch

Pennsylvania, United States

Submitter(s)

LF

Louis C. Fielding, MS

COO
Empirical Spine
San Carlos, California, United States

Introduction
Durable surgical outcome for patients with degenerative spondylolisthesis (DS) usually requires decompression and fusion. The addition of fusion increases the complexity of surgery and results in greater stress on adjacent levels with resultant increased incidence of adjacent segment degeneration. A novel dynamic sagittal tether is proposed for segmental stabilization after decompression for DS, as an alternative to fusion. An FDA IDE study (NCT03115983) compares direct surgical decompression and stabilization with the dynamic sagittal tether (treatment group; D+DST) to decompression and instrumented TLIF (control group; D+TLIF) for symptomatic DS.

Aims/Objectives
Evaluate propensity score (PS) adjusted outcomes comparing decompression and DST stabilization versus decompression and TLIF for symptomatic grade I DS at 2 years after surgery.

Methods
All patients had grade I DS and spinal canal stenosis with ODI≥35 and VAS-leg/hip≥50 (full eligibility criteria at clinicaltrials.gov, NCT03115983). Patients received either D+DST or D+TLIF at the level of DS, with or without an adjacent level decompression if indicated. Patient-reported outcomes were collected preoperatively and through 24-months follow-up. Perioperative outcomes were collected and reoperations at the index or adjacent level were tracked through 24-months. A propensity score (PS) model was used to select patients in balanced subgroups based on preoperative variables for comparison in this parallel-assignment, prospective clinical trial.

Results
287 enrolled patients were selected for matching in the PS model. In the DST group, surgery was 70±15 min shorter, resulted in 183±44 ml less blood loss and 2.3±0.4 days shorter hospital stay vs the TLIF group. Mean improvements at 24 months for the DST/TLIF groups were 40.0/32.9 ODI, 48.3/41.8 VAS back pain and 58.0/56.1 VAS leg/hip pain, with 91.2%/83.0% achieving 15-point ODI improvement. The DST group had significantly lower ODI at 6-weeks and 3-months. Reoperation rates through 24mo at the index or adjacent segments were 7.2%/9.8% for the DST/TLIF groups. Of the 10/14 DST/TLIF reoperations there were 3/1 additional decompressions, 5/1 index level fusions, 0/3 adj-level fusions, 1/7 index+adjacent level fusions, 1/1 I/D for infection and 0/1 dural repair. Imaging demonstrated no increased instability in the DST group. At 24-months in the DST/TLIF groups, ROM was reduced 1.7°/3.7° and translation was reduced 0.4mm/1.0mm, while ROM was more evenly maintained across the index and adjacent levels in the D+DST group.

Conclusions
These results suggest that decompression with DST stabilization for degenerative spondylolisthesis can result in quicker but durable clinical improvement compared with fusion, without an increase in reoperations during the 24-month postoperative period. Similarly, statistically significant improvements in patient-reported outcomes were demonstrated in each group, with lower disability scores in the DST group at all postoperative timepoints. Imaging demonstrated no increased instability in the DST group with preserved baseline distribution of motion between the index and adjacent segments. While these groups were PS-selected with PS-adjusted differences, further analyses will include quantitative comparison between groups per the pre-defined composite clinical success criteria for a definitive clinical comparison of outcomes.