Yellow flag on prognostic factors for non-specific chronic low back pain patients subjected to mini-invasive treatment: a cohort study

Objectives: Research was conducted to study the efficacy of analgesic infiltration treatment in a well-selected population of patients with non-specific drug-resistant chronic low back pain. It studied the pain on a numeric rating scale and the physical and mental condition of patients using a short-form health survey-36, before and six months after invasive pain treatment.

Design: This is a prospective observational single center cohort study.

Setting: The study took place in the Multimodal Pain Therapy Unit of the IRCCS Institute of Neurological Sciences in Bologna, Italy.

Subjects: Four hundred and thirteen out of a total 538 patients admitted to the unit with non-specific drug-resistant chronic low back pain were enrolled in the study.

Method: Patients were enrolled with written consent between April 2017 and November 2018. The study assessed NRS, BDI and SF-36 scores before and six months after mini-invasive treatment.

Results: There is an inverse correlation between Mental Component Scale (MCS) and Physical component scale as measured by SF-36. Older patients in a worse physical condition but with a more positive outlook on their quality of life were more likely to improve after invasive treatment (p < 0.001). The BDI scale is more effective in the diagnosis of depression than MCS.

Conclusions: The prognostic value of MCS given to the patient before mini-invasive treatment could lead physicians to adopt a multimodal approach that includes consideration of the psychological features of pain and possibly antidepressant therapy.

Keywords: Chronic low back pain; Drug resistance; Health-related quality of life; Mental component scale; Pain management; Physical component scale; SF-36.