Does the Number of Levels Fused Affect Spinopelvic Parameters and Clinical Outcomes Following Posterolateral Lumbar Fusion for Low-Grade Spondylolisthesis?

STUDY DESIGN

Retrospective cohort.

OBJECTIVES

To determine how the number of fused intervertebral levels affects radiographic parameters and clinical outcomes in patients undergoing open posterolateral lumbar fusion (PLF) for low-grade degenerative spondylolisthesis.

METHODS

This was a retrospective cohort study on patients who underwent open PLF for low-grade spondylolisthesis at a single institution from 2011 to 2018. Patients were divided into groups based on number of levels fused during their procedure (1, 2, or 3 or more). Preoperative and postoperative spinopelvic radiographic parameters, patient-reported outcomes (Visual Analog Scale [VAS]-back, VAS-leg, Oswestry Disability Index [ODI]), and postoperative complications were compared.

RESULTS

Of the 316 patients eligible (203 one-level, 95 two-level, 18 three or more levels), change in initial postoperative to final pelvic incidence-lumbar lordosis was greatest in 2-level fusions ( = .039), while 3 or more level fusions had worse final pelvic tilt measures ( = .021). In addition, multilevel fusions had worse final VAS-back scores (2-level: = .015; 3 or more levels: = .011), higher rates of dural tears (2-level: = .001), reoperation (2-level: = .039), and discharge to facility (3 or more levels: = .047) when compared with 1-level fusions.

CONCLUSIONS

Patients in multilevel fusions experienced less improvement in back pain, had more complications, and were more commonly discharged to a facility compared with single-level PLF patients. These findings are important for operative planning, for setting appropriate preoperative expectations, and for risk stratification in patients undergoing posterior lumbar fusion for low-grade spondylolisthesis.