Influence of Handgrip Strength and Psoas Muscle Index on Analgesic Efficacy of Epidural Steroid Injection in Patients With Degenerative Lumbar Spinal Disease

Handgrip strength (HGS) and psoas muscle index (PMI) are widely used protocols for screening or diagnosing sarcopenia by measuring muscle strength and mass. Epidural steroid injection (ESI) is a common intervention for the treatment of spinal pain; however, the influence of pre-procedural sarcopenic status on therapeutic effects after ESI has not been investigated.

In the present study, whether pre-procedural HGS or PMI predicts analgesic efficacy of ESI in elderly patients with degenerative lumbar spinal disease was investigated.

This was a retrospective observational study.

The study included patients from the outpatient department for interventional pain management at a university hospital.

Following institutional review board (IRB) approval, patients >= 65 years of age who underwent fluoroscopy-guided lumbar ESI from 2016 to 2017 in our clinic were enrolled in the present study. Good analgesia was defined as >= 50% reduction in pain score at 4 weeks after injection. Patient characteristics, pain-related factors, clinical factors, HGS, and PMI measurements were collected and analyzed using multivariate analysis to identify the predictors of good analgesia after lumbar ESI. In addition, a receiver operating characteristic curve (ROC) analysis was performed, and area under the curve (AUC) values with 95% confidence interval (CI) were calculated for the HGS.

A total of 259 patients satisfied the study protocol requirements. HGS was significantly higher in the good analgesia group (23.12 ± 7.54 vs 16.55 ± 6.66 kg, P < 0.001). However, the PMI did not differ between the 2 groups (5.25 ± 1.55 vs 5.08 ± 1.69 cm2/m2, P = 0.406). Multivariate analysis revealed higher HGS (odds ratio, OR = 1.142, 95% CI = 1.094-1.193, P < 0.001) and low-grade foraminal stenosis (OR = 0.403, 95% CI = 0.199-0.814, P = 0.011) were significantly associated with good analgesia after injection. The AUC values with 95% CI for HGS were 0.819 (0.718-0.920) in men and 0.800 (0.732-0.869) in women. In addition, HGS cutoff values for predicting good analgesic outcomes were 26.5 kg in men and 16.5 kg in women.

This study was conducted in a single center, and sample size was relatively small. The lack of physical performance evaluation did not fully meet the current criteria for sarcopenia. In addition, post-procedural clinical data associated with disability or quality of life could not be collected.

In the present study, pre-procedural HGS was an independent predictor of analgesic efficacy after ESI in elderly patients with degenerative lumbar spinal disease. However, the PMI was not associated with pain relief after injection.