Hand grip strength can predict clinical outcomes and risk of falls after decompression and instrumented posterolateral fusion for lumbar spinal stenosis.

Abstract

There has been limited research on the association between hand grip strength (HGS) as one of the diagnostic criteria for sarcopenia and surgical outcomes of lumbar spinal stenosis (LSS). We aimed to determine the effect of HGS on surgical outcomes and risk of fall in patients with LSS. This is a retrospective observational study. We included 200 patients who underwent spinal surgery for LSS. We recorded clinical outcome parameters, including Oswestry Disability Index (ODI), Euro-QOL (EQ-5D), and visual analog scale (VAS) scores for back or leg pain. To assess the risk of fall we used HGS and four functional mobility tests (alternative step test, six-meter walk test, timed up and go test, sit-to-stand test). ODI, EQ-5D, and VAS scores for back and leg pain were assessed preoperatively and 1 year after surgery. The four functional mobility tests were assessed at each time point during the 1-year follow-up period to assess the risk of fall in patients with LSS. We divided the patient cohort according to sex and allocated them into two different groups based on HGS: high HGS (≥26 kg for men, n=26; ≥18 kg for women, n=35), and low HGS (<26 kg for men, n=48; <18 kg for women, n=91). The pre- and postoperative ODI, EQ-5D, and VAS scores for back and leg pain, as well as the functional mobility test results, and demographic data were compared between the two groups using independent t tests. Correlations between HGS and clinical outcome parameters were analyzed using Pearson correlation. In women and men, HGS correlated with the preoperative/postoperative ODI (r₁=-0.217/r₂=-0.345 in women, and r₁=-0.384/r₂=-0.411 in men) and EQ-5D scores (r₁=0.190/r₂=0.309 in women, and r₁=0.373/r₂=0.467 in men). HGS also correlated with the four postoperative results for the functional mobility tests: alternative step test (r=-0.238 in women, r=-0.431 in men), six-meter walk test (r=-0.232 in women, r=-0.282 in men), timed up and go test (r=-0.285 in women, r=-0.359 in men), and sit-to-stand test (r=-0.238 in women, r=-0.251 in men). The preoperative and postoperative ODI and EQ-5D scores in the high HGS group were superior to those in the low HGS group. Among the four functional mobility tests, preoperative and postoperative six-meter walk test results showed improvements in the high HGS group. Considering the multifactorial nature of falls, HGS may be a useful surrogate marker for predicting the risk of falls and clinical outcomes in patients with LSS.