Lumbar spinal stenosis associated with progression of locomotive syndrome and lower extremity muscle weakness

Abstract

Purpose: The purpose of this study was to evaluate the association between the early stages of lumbar spinal stenosis (LSS) and the risk of locomotive syndrome, as well as its effect upon muscle strength of the back, upper extremities, and lower extremities.

Patients and methods: LSS was diagnosed with a self-administered, self-reported history questionnaire. Participants (n=113) who agreed to be tested by the diagnostic support tool for LSS underwent three risk tests for locomotive syndrome: a stand-up test, a two-step test, and a 25-question Geriatric Locomotive Function Scale (GLFS-25), as well as measurements of the strength of their grip, back extensor, hip flexor, and knee extensor muscles.

Results: Twenty-three participants were diagnosed with LSS by the questionnaire. Results of the stand-up test in the LSS group were significantly worse than those in the no-LSS group (P=0.003). The results of the two-step test and the total score on the GLFS-25 in the LSS group were significantly worse than those in the no-LSS group (P=0.002 and P<0.0001, respectively). The stages of locomotive syndrome assessed by the stand-up test, two-step test, and the GLFS-25 were significantly worse in the LSS group than in the no-LSS group (P=0.0004, P=0.0007, and P<0.0001, respectively). Hip flexor and knee extensor strength, but not grip and back extensor strength, in the LSS group were significantly lower than that in the no-LSS group.

Conclusions: LSS diagnosed using the self-reported support tool worsened the stage of locomotive syndrome in older people. Furthermore, participants with LSS had significant lower extremity weakness.

Keywords: back extensor strength; grip strength; locomotive syndrome; locomotive syndrome risk test; lower extremity muscle strength; lumbar spinal stenosis.

Figure 1

The muscle strength of the lower extremities, including hip flexors (A) and knee extensors (B), was measured with a handheld dynamometer (Commander™ PowerTrack II™ Handheld Dynamometer; Nihon Medix Co., Ltd., Matsudo, Japan). The mean strength of the two lower extremities was calculated and all calculations were performed twice. Isometric back extensor strength in the prone position was measured using a strain-gauge dynamometer (DPU-1000N Digital Force Gauge; Imada, Toyohashi, Japan) (C). The subject was aligned on the board with a strain-gauge dynamometer attached to the subject’s back. After the strain-gauge was placed (at the mid-portion of back at the inferior part of scapula), we asked the subject to lift their upper trunk as high as possible. The strain-gauge recorded the maximum strength. Measurements were performed three times and the values from the trial that produced the greatest force were selected.