Preoperative Elevated Levels for Depression, Anxiety, and Subjective Mental Stress Have No Influence on Outcome Measures of Peripheral Nerve Field Stimulation for Chronic Low Back Pain-A Prospective Study.

Objective: Peripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. The treatment of low back pain strongly depends on psychological factors like anxiety, depression, and mental stress. The aim of this study was to evaluate the impact of such factors on outcome measures after lead- and implantable pulse generator-implantation.

Materials And Methods: Between 2014 and 2019, a prospective cohort study of 39 patients with chronic lumbar pain was conducted. Hospital Anxiety and Depression Scale (HADS) score was assessed at baseline to measure symptoms of anxiety and depression. Symptom checklist-90 (SCL-90) was used to measure subjective psychopathology. Pain intensity (numeric pain rating scale [NRS]), SF12v2 with Physical Component Summary and Mental Component Summary (MCS) scores, and Oswestry Disability Index (ODI) were assessed pre- and postoperatively as well as three and six months after PNFS implantation. Outcome values were compared to baseline data. Statistical analysis was performed using depending t-test and analysis of variance (ANOVA). A p value <0.05 was considered significant.

Results: The cohort consisted of 39 patients (18 females, 21 males) with a median age of 61 years (IQR  = 52-67 years). NRS, ODI, and SF12v2 showed significant improvement in the whole follow-up period compared to baseline values (p < 0.05). Elevated HADS scores for anxiety were seen in 64.1%, for depression in 76.9% of the patients at baseline. SCL-90 was pathologic in 71.8% of the cases. A one-way ANOVA revealed no differences between elevated HADS- and SCL-90 values and all outcome measures after PNFS implantation in the whole follow-up period (p > 0.05).

Conclusion: Chronic low back pain is often associated with psychological distress. Our study showed highly elevated levels for anxiety and depression as well as subjective mental stress in patients with chronic low back pain without negative impact on NRS, ODI, and SF12v2 in the whole follow-up after PNFS implantation.