Study design:

Retrospective analysis on prospectively collected data.

Objectives:

To compare posterior lumbar fusions with versus without an interbody in: 1) patient-reported outcomes (PROs) at 1 year, and 2) postoperative complications, readmission, and reoperations.

Summary of background data:

Elective lumbar fusion is commonly used to treat various lumbar pathologies. Two common approaches for open posterior lumbar fusion include posterolateral fusion (PLF) alone without an interbody and with an interbody through techniques like the transforaminal lumbar interbody fusion (TLIF). Whether fusion with or without an interbody leads to better outcomes remains an area of active research.

Methods:

The Lumbar Module of the Quality Outcomes Database (QOD) was queried for adults undergoing elective primary posterior lumbar fusion with or without an interbody. Covariates included demographic variables, comorbidities, primary spine diagnosis, operative variables, and baseline patient-reported outcomes (PROs), including Oswestry Disability Index (ODI), North American Spine Society (NASS) satisfaction index, numeric rating scale (NRS)-back/leg pain, and Euroqol 5-Dimension (EQ-5D). Outcomes included complications, reoperations, readmissions, return to work/activities, and PROs. Propensity score matching and linear regression modeling were used to estimate the average treatment effect on the treated (ATT) in order to assess the impact of interbody use on patient outcomes.

Results:

After propensity matching, there were 1,044 interbody patients and 215 PLF patients. ATT analysis showed that having an interbody or not had no significant impact on any outcome of interest, including 30-day complications and reoperations, 3-month readmissions, 12-month return to work, and 12-month PROs.

Conclusion:

There were no discernible differences in outcomes between patients undergoing PLF alone versus with an interbody in elective posterior lumbar fusion. These results add to the growing body of evidence that posterior lumbar fusions with and without an interbody appear to have similar outcomes up to one year postoperatively when treating degenerative lumbar spine conditions.