Foot pressure transfers are altered in lumbar radiculopathy but reversible after surgery: a prospective, pedobarography study.

ABSTRACT

BACKGROUND CONTEXT Patients with lower lumbar stenosis and disc herniation report disability in standing and ambulation, despite normal neurological examination. The L5 and S1 nerve roots support the entire motor and sensory function of the foot, and their radiculopathy can affect foot loading during standing and walking. This has not been quantified before. PURPOSE: To quantify alterations in static and dynamic foot pressure transfers in patients with lower lumbar nerve root compression, and document any beneficial effects of surgical decompression. STUDY DESIGN: Prospective, case-control study. PATIENT SAMPLE Cases-Patients with unilateral radiculopathy (L5/S1) with normal neurology (n=50); Controls - Healthy volunteers (n=50). METHODS: The volunteers and patients underwent pedobarographic analysis during standing (static) and walking (dynamic), and fifteen (12 dynamic and three static) parameters were documented. The patient's preoperative values were compared with that of the healthy volunteers. All the 50 patients underwent surgical decompression, and clinical outcome measures (VAS/ODI at 3 months) were documented. Pedobarographic analysis was repeated in the postoperative period (48 hours) and 3-month follow-up and compared with the preoperative scores. RESULTS: In healthy controls, the mean values of all 15 parameters were comparable between the right and the left side (p>.05). When compared to controls, the patients had significantly lower maximum foot loads (p=.01) and average foot loads (p=.05) on the affected side during walking indicating lesser load transmission, in the preoperative period. Within the affected foot, the load transfer was higher on the first metatarsal/ medial arch while significantly less on the lateral metatarsals (p=.04). The percentage load on whole foot and forefoot was significantly less on standing (p=.01). Significant improvements were noted in the postoperative period, especially in the maximum foot surface area (p=.01), maximum and average foot loads, and improved weight transfers on lateral arch and forefoot (p=.02). The load on whole foot increased significantly from 46.1%±5.5% (preoperative) to 48.1%±5.5% (postoperative) and 49.9%±3.3% at follow-up (p=.01). CONCLUSION: This is the first study using pedobarography to document altered foot pressure patterns during ambulation in patients with disc herniation and stenosis. Decreased load transfer, asymmetrical and unphysiological distribution of pressures on the affected foot were observed during weight bearing, which improved after surgical decompression.