Functional Limitations Due to Lumbar Stiffness in Adults With and Without Spinal Deformity.

STUDY DESIGN: Cross-sectional analysis. OBJECTIVE: To compare Lumbar Stiffness Disability Index (LSDI) scores between asymptomatic adults and patients with spinal deformity. SUMMARY OF BACKGROUND DATA: The LSDI was designed and validated as a tool to assess functional impacts of lumbar spine stiffness and diminished spinal flexibility. Baseline disability levels of patients with adult spinal deformity (ASD) are high as measured by multiple validated outcome tools. Baseline lumbar stiffness-related disability has not been assessed in adults with and without spinal deformity. METHODS: The LSDI and Scoliosis Research Society-22r (SRS-22r) were submitted to a group of asymptomatic adult volunteers. Additionally, a multicenter cross-sectional cohort analysis of patients with ASD from 10 centers was conducted. Baseline LSDI and SRS-22r were completed for both operatively and nonoperatively treated patients with deformity. RESULTS: The LSDI was completed by 176 asymptomatic volunteers and 693 patients with ASD. Mean LSDI score for asymptomatic volunteers was 3.4 +/- 6.3 out of a maximum score of 100, with significant correlation between increasing age and higher (worse) LSDI score (r = 0.30, P = 0.0001). Of the patients with spinal deformity undergoing analysis, 301 subsequently underwent surgery and 392 were subsequently treated nonoperatively. Operative patients had significantly higher preoperative LSDI scores than both nonoperative patients and asymptomatic volunteers (29.9 vs. 17.3 vs. 3.4, P < 0.0001 for both). For patients with ASD, significant correlations were found between LSDI and SRS-22 Pain and Function subscales (r = -0.75 and -0.76, respectively; P < 0.0001 for both). CONCLUSION: LSDI scores are low among asymptomatic volunteers, although stiffness-related disability increases with increasing age. Patients with ASD report substantial stiffness-related disability even prior to surgical fusion. Stiffness-related disability correlates with pain- and function-related disability measures among patients with spinal deformity.