Defining Clinically Meaningful Functional Recovery Following Lumbar Spine Surgery: Minimal Clinically Important...

Area of Science:

• Biomedical Engineering
• Clinical Biomechanics
• Orthopedics

Background:

• Objective gait and balance assessments are crucial for understanding functional impairment in lumbar degenerative spine disease.
• Current lack of minimal clinically important difference (MCID) thresholds hinders the clinical application of these assessments.

Purpose of the Study:

• To establish MCID thresholds for objective gait and balance biomarkers in patients undergoing surgical treatment for lumbar degenerative spine disease.

Main Methods:

• A prospective longitudinal cohort study involving 111 patients undergoing surgery for lumbar degenerative spine disease.
• Evaluated spatiotemporal gait parameters, Gait Deviation Index (GDI), and balance metrics (head, CoM, CoP sway) using 3D motion analysis preoperatively and at 3, 6, and 12 months postoperatively.
• Calculated MCIDs using distribution-based, measurement error-based, and anchor-based methods, averaging estimates for final thresholds.

Main Results:

• Defined clinically meaningful MCID thresholds for gait parameters: walking speed (0.14 m/s), cadence (7.8 steps/min), stride time (0.11 s), and step length (0.05 m).
• Established MCIDs for balance metrics: head sway (0.95-0.98 cm), center of mass sway (0.51-0.54 cm), and center of pressure sway (0.57-0.70 cm planar, 28.71 cm total excursion).
• MCID estimates showed consistency for gait variables but greater variability for balance metrics across different calculation methods.

Conclusions:

• This study successfully defined clinically interpretable MCID thresholds for objective gait and balance biomarkers in lumbar degenerative spine disease.
• These established thresholds facilitate the integration of motion analysis into clinical practice for precise interpretation of postoperative functional recovery.