[Failed back surgery syndrome: the role of central sensitization and treatment approaches].

OBJECTIVE

To study a role of central sensitization (CS) in patients with Failed Back Surgery Syndrome (FBSS) after decompression of the lumbar and/or sacral roots.

MATERIAL AND METHODS

The study included three groups of patients: 1) early FBSS (e-FBSS, =23), pain after surgery decreased, but continued to significantly bother the patient, or recurred in the first 6 months after surgery; 2) middle FBSS (m-FBSS, =42), pain after surgery completely stopped, but recurred within 6-12 months; 3) late FBSS (l-FBSS, =31), if pain relapse occurred more than 12 months later. Neurological status assessment, study of muscle trigger zones (MTZ), postoperative scar trigger zones (TZS), pain assessment according to the Visual Analogue Scale (VAS), CS assessment according to the Russian version of the Central Sensitization Inventory (CSI) were performed. Treatment included the following stages: stage 1 (non-steroidal anti-inflammatory drug (NSAID) meloxicam 15 mg 7 days); stage 2 (aminophenylbutyric acid hydrochloride (APAH) 250 mg 3 times a day 14 days); stage 3 (fluvoxamine 50 mg daily 8 weeks); stage 4 (MTZ and TZS treatment, fitness program). In addition to the previously described 96 patients, 15 patients (4 men and 11 women, aged 36-47 years) with FBSS and widespread pain, corresponding to the criteria for fibromyalgia ACTTION-APS Pain Taxonomy, who took only milnacipran 25-50 mg daily for two months (WSP-FBSS group), were studied.

RESULTS

At baseline, CSI and VAS are as follows: CSI=72.2±6.5; VAS=58.5±8.8 in the e-FBSS group; CSI=49.2±9.0; VAS=39.5±5.3 in the m-FBSS group; CSI=18.1±5.9; VAS=18.1±5.4 in the l-FBSS group. All patients have active MTZ and TZS. The differences between MTZ and TZS subgroups were in the reproduction of pain - the appearance of pain characteristic of the patient during stimulation (pressure) of the MTZ or TZS. In the e-FBSS group, there is the low efficacy of NSAIDs, the moderate efficacy of APAH, the high efficacy of fluvoxamine. In the m-FBSS group, the moderate efficacy of NSAIDs and APAH and the high efficacy of fluvoxamine are observed. In the l-FBSS group, there is the high efficacy of NSAIDs. In the WSP-FBSS group, VAS and CSI are 58.8±9.2 mm and 75.1±8.04, respectively, before treatment, 15.51±5.1 mm (=0.00032) and 25.6±8.2 (=0.0002), respectively, after 2 months of treatment.

CONCLUSIONS

In patients with FBSS, MTZ and TZS should be treated taking into account CS. The study shows the efficacy of APAH, fluvoxamine and milnacipran in the presence of CS.