Quantifying postural recovery after lumbar decompression: cone of economy biomarkers of balance effort and stability in patients with radiculopathy and neurogenic claudication.

BACKGROUND CONTEXT: Degenerative lumbar spine pathology manifesting as radiculopathy and neurogenic claudication often leads to impaired postural stability, compensatory movement strategies, and increased fall risk. Conventional clinical assessments and patient-reported outcomes inadequately characterize dynamic balance dysfunction and postural control deficits that persist after surgical intervention.

PURPOSE: To objectively quantify changes in postural stability, balance effort, and Cone of Economy (CoE) control following lumbar decompression surgery in patients with radiculopathy and neurogenic claudication using high-resolution three-dimensional motion analysis.

STUDY DESIGN/

SETTING

Prospective, single-center cohort study.

PATIENT SAMPLE: Thirty-six adults (mean age 70.1±11.4 years) with symptomatic degenerative lumbar spinal stenosis undergoing open decompression surgery.

OUTCOME MEASURES: Postural sway and stability metrics, including CoE dimensions, center-of-pressure (CoP) and center-of-mass (CoM) excursion, sway path and velocity, phase-plane stability, frequency-domain characteristics, and joint-level compensatory excursions, along with patient-reported outcomes (Oswestry Disability Index, PROMIS, Tampa Scale of Kinesiophobia).

METHODS

Participants completed standardized three-dimensional balance assessments 1 week before and 3 months after decompression using a 41-marker motion capture system synchronized to dual force plates. Mixed-effects models tested pre- to postoperative changes, accounting for age, BMI, and repeated measures with false discovery rate correction for multiple comparisons.

RESULTS

Lumbar decompression was associated with significant improvements in mediolateral postural control. Center-of-pressure mediolateral sway decreased from 2.24±0.92 cm to 1.70±0.69 cm (p=.007), head coronal sway from 3.29±1.11 cm to 2.38±0.87 cm (p=.001), and CoM coronal sway from 1.85±0.74 cm to 1.40±0.63 cm (p=.009). Expanded balance metrics demonstrated reductions in total head sway path area (9.55±3.12 → 6.47±2.41; p=.001), improved phase-plane stability (p<.001), and decreased low- and mid-frequency sway power (p≤.014). Compensatory strategies at the cervical spine, lumbar coronal motion, pelvis, and hips were significantly reduced postoperatively, while knee and ankle kinematics were maintained. Patient-reported disability and pain interference improved (ODI -16.8, PROMIS Pain -8.2; both p<.001), with significant reductions in kinesiophobia (TSK -7.1; p<.001).

CONCLUSIONS

Lumbar decompression was associated with quantifiable improvements in postural stability and balance efficiency. High-resolution sway and CoE metrics provide objective, mechanistic biomarkers of functional recovery that complement traditional patient-reported outcomes. These findings support the potential role of dynamic balance assessment in postoperative evaluation and rehabilitation planning to reduce fall risk and optimize functional outcomes after lumbar spinal decompression.