The Impact of Paraspinal Muscle Degeneration on Oswestry Disability Index Subsections Two Years After Spinal Surgery for Degenerative Lumbar Spondylolisthesis.

STUDY

DESIGN

Secondary analysis of the prospective study.

OBJECTIVE

To investigate the impact of fatty infiltration (FI) in the paraspinal muscles (PMs) on postoperative Oswestry Disability Index (ODI) subsection scores in patients undergoing elective lumbar surgery for degenerative lumbar spondylolisthesis (DLS).

BACKGROUND

DLS can increase FI in the PM like the multifidus (MF), erector spinae (ES), and psoas (PS), leading to greater spinal disability and higher ODI scores. It is unclear whether increased PM FI affects all ODI subsections equally.

MATERIALS AND

METHODS

This study reviewed data from a single-center cohort of patients with DLS who underwent elective lumbar surgery. Overall ODI and the subsection scores were prospectively assessed before and 2 years postsurgery. FI of the PS, MF, and ES was measured using T2-weighted magnetic resonance imaging images. The relationship between PM FI and postoperative ODI subsections was analyzed, using multivariable linear regression analysis.

RESULTS

Overall, 229 patients (59% females, mean age of 67 ± 8 yr) were included with an overall baseline ODI of 50 (40-62) and a postoperative ODI of 16 (2-34). The highest preoperative subsection scores were seen in pain intensity [4 (2-4)], changing degree of pain [4 (3-4)], lifting [4 (1-5)], and standing [4 (3-4)]. PM measurements showed a mean FI of 41 ± 10% for ES, 58 ± 15% for MF, and 6 ± 5% for PS. Patients with increased ES FI were more likely to show higher postoperative scores in all ODI subsections and in the overall ODI (Est = 0.45, 95% CI: 0.20-0.71, P = 0.004). Increased MF FI was significantly associated with higher postoperative ODI subsection scores in standing (Estimates (Est) = 0.02, 95% CI: 0.01-0.03, P = 0.033) and walking (Est = 0.02, 95% CI: 0.01-0.03, P = 0.017).

CONCLUSION

Increased ES FI is significantly associated with higher ODI scores across all subsections 2 years after lumbar surgery, whereas higher MF FI is linked to greater disability in standing and walking. These findings underscore the need to maintain PM health to improve surgical planning, improve rehabilitation outcomes, and reduce postoperative disability.