SPINE SECTION Original Research Article Evaluation of Low Back Pain: Comparative Study Between Psychophysical Methods

Objective. The aims of this study were to validate the measurement of low back pain by different psy- chophysical methods and to compare different methods of pain measurement. Methods. This double-blind, randomized experi- mental study was realized in Brazil. The sample was 60 patients with low back pain, divided into two groups: group I (methylprednisolone 80 mg + 8m L of 0.9% saline solution) and group II (methylpred- nisolone 80 mg + 5 mL of levobupivacaine without epinephrine + 3 mL of 0.9% saline solution), both using 10-mL syringes. The methods were the serial exploration and psychophysical (magnitude estimation, category estimation, and cross-modality matching). Results. Pain evaluation was carried out before the block and 30 minutes, 6, 12, and 24 hours after it. After 30 minutes of epidural block, the levobupiv- acaine group presented more significant reaction of reduction pain than the saline group. The magnitude and line-length scales were evaluated every period of time, showing no significant differences, except in 12 and 24 hours after the first block. The expo- nential function to every evaluation ranged from 0.87 to 1.00. Conclusion. This research tries to bring to health care an original method for measuring low back pain. It is noteworthy that in the future, more research is needed to apply this method in clinical and scientific fields.