Foot Tapping Test as a Simple Quantitative Index of Motor Function for Lumbosacral Radiculopathy

Study design: We conducted a retrospective review of data from patients who underwent surgical treatment for lumbosacral radiculopathy.

Objective: To assess the effectiveness of the foot tapping test (FTT) in evaluating lower limb motor function in patients with lumbosacral radiculopathy pre and postsurgery.

Background: Lumbosacral radiculopathy is becoming increasingly common in aging populations. Despite standard treatments, paralysis often leads to incomplete postoperative recovery, necessitating early detection and interventions.

Patients and methods: We enrolled individuals who underwent surgery for lumbosacral radiculopathy at our facility between 2009 and 2020. Patients with a history of lumbar surgeries, dialysis, rheumatoid arthritis, and transitional vertebrae were excluded. The FTT score was measured by having the sole of the foot tap as many times as possible for 10 seconds while keeping the heel in contact with the floor. The L4, L5, and S1 groups were assigned using the scores on the side of the radiculopathy, and the control group was assigned using the scores on the intact side. Data were analyzed using the Dunnett test for group comparisons and paired t -tests for pre and postsurgery comparisons.

Results: Of the 522 eligible patients, 80 (159 nerve roots, 1 patient with hemi-prosthetic leg) were analyzed. The preoperative FTT scores in the L4 and L5 groups were significantly lower than those in the control group, indicating functional impairment. One year postsurgery, all groups showed improvements in FTT scores, with the L5 group exhibiting significant improvements compared with the control; this was supported by the results of sensitivity analyses considering the effects of paralysis and pain.

Conclusion: The FTT is a valuable tool for the early detection of lower limb motor dysfunction in lumbosacral radiculopathy, particularly for L5 nerve root impairment, where it aids in timely surgical intervention and may improve postoperative outcomes and quality of life.