Motor corticospinal excitability abnormalities differ between distinct chronic low back pain syndromes.

OBJECTIVES: It is not known whether cortical plastic changes reported in low-back pain (LBP) are present in all etiologies of LBP. Here we report on the assessment of patients with three LBP conditions: non-specific-LBP (ns-LBP), failed back surgery syndrome (FBSS), and sciatica (Sc). METHODS: Patients underwent a standardized assessment of clinical pain, conditioned pain modulation (CPM), and measures of motor evoked potential (MEPs)-based motor corticospinal excitability (CE) by transcranial magnetic stimulation, including short interval intracortical inhibition (SICI), and intracortical facilitation (ICF). Comparisons were also made with normative data from sex- and age-matched healthy volunteers. RESULTS: 60 patients (42 women, 55.1±9.1 years old) with LBP were included (20 in each group). Pain intensity was higher in patients with neuropathic pain [FBSS (6.8±1.3), and Sc (6.4±1.4)] than in those with ns-LBP (4.7±1.0, P<0.001). The same was shown for pain interference (5.9±2.0, 5.9±1.8, 3.2±1.9, P<0.001), disability (16.4±3.3, 16.3±4.3, 10.4±4.3, P<0.001), and catastrophism (31.1±12.3, 33.0±10.4, 17.4±10.7, P<0.001) scores for FBSS, Sc, and ns-LBP groups, respectively. Patients with neuropathic pain (FBSS, Sc) had lower CPM (-14.8±1.9, -14.1±16.7, respectively) compared to ns-LBP (-25.4±16.6; P<0.02). 80.0% of the FBSS group had defective ICF compared to the other two groups (52.5% for ns-LBP, P=0.025 and 52.5% for Sc, P=0.046). MEPs (140%-rest motor threshold) were low in 50.0% of patients in the FBSS group compared to 20.0% of ns-LBP (P=0.018) and 15.0% of Sc (P=0.001) groups. Higher MEPs were correlated with mood scores (r=0.489), and with lower neuropathic pain symptom scores(r=-0.415) in FBSS. CONCLUSIONS: Different types of LBP were associated with different clinical, CPM and CE profiles, which were not uniquely related to the presence of neuropathic pain. These results highlight the need to further characterize patients with LBP in psychophysics and cortical neurophysiology studies.

Failed back surgery pain syndrome: therapeutic approach descriptive study in 56 patients.

OBJECTIVE: The authors show the clinical evaluation and follow-up results in 56 patients diagnosed with a failed back surgery pain syndrome. METHODS: Descriptive and prospective study conducted over a one-year period. In this study, 56 patients with a failed back surgery pain syndrome were assessed in our facility. The age ranged from 28 to 76 years (mean, 48.8 ± 13.9 years). The pain was assessed through a Visual Analog Scale (VAS). RESULTS: Postoperative pain was more severe (mean VAS score 8.3) than preoperative pain (7.2). Myofascial pain syndromes (MPS) were diagnosed in 85.7% of patients; neuropathic abnormalities associated or not with MPS were found in 73.3%. Drug therapy associated with physical medicine treatment provided > 50% pain improvement in 57.2% of cases; trigger point injection in 60.1%, and epidural infusion of morphine with lidocaína in 69.3% of refractory cases. CONCLUSION: In patients with a post-laminectomy syndrome, postoperative pain was more severe than preoperative pain from a herniated disk. A miofascial component was found in most patients.

Síndrome dolorosa pós-laminectomia: estudo descritivo da abordagem terapêutica em 56 pacientes / Failed back surgery pain syndrome: therapeutic approach descriptive study in 56 patients

OBJETIVO: Os autores apresentam os resultados da avaliação clínica e acompanhamento de 56 pacientes com diagnóstico de síndrome dolorosa pós-laminectomia lombar. MÉTODOS: Estudo descritivo, prospectivo realizado no período de um ano. Neste estudo foram avaliados 56 pacientes caracterizados com síndrome dolorosa pós-laminectomia lombar em nossa instituição. As idades variaram de 28 a 76 anos (média de 48,8 ± 13,9 anos). Avaliação da dor com Escala Visual e Analógica (EVA). RESULTADOS: A dor pós-operatória foi mais intensa (8,3, média de EVA) que a pré-operatória (7,2). Síndrome dolorosa miofascial (SDM) foi diagnosticada em 85,7 por cento dos pacientes, anormalidades neuropáticas associadas ou não à SDM em 73,3 por cento. O tratamento farmacológico associado à medicina física proporcionou melhora de mais de 50 por cento da dor em 57,2 por cento dos casos, a infiltração dos pontos-gatilho miofasciais em 60,1 por cento e a infusão de morfina com lidocaína no compartimento epidural lombar em 69,3 por cento dos casos refratários. CONCLUSÃO: Nos pacientes com síndrome pós-laminectomia, a dor pós-operatória foi mais intensa que a dor pré-operatória da hérnia de disco. Um componente miofascial foi verificado na maioria dos doentes.

OBJECTIVE: The authors show the clinical evaluation and follow-up results in 56 patients diagnosed with a failed back surgery pain syndrome. METHODS: Descriptive and prospective study conducted over a one-year period. In this study, 56 patients with a failed back surgery pain syndrome were assessed in our facility. The age ranged from 28 to 76 years (mean, 48.8 ± 13.9 years). The pain was assessed through a Visual Analog Scale (VAS). RESULTS: Postoperative pain was more severe (mean VAS score 8.3) than preoperative pain (7.2). Myofascial pain syndromes (MPS) were diagnosed in 85.7 percent of patients; neuropathic abnormalities associated or not with MPS were found in 73.3 percent. Drug therapy associated with physical medicine treatment provided > 50 percent pain improvement in 57.2 percent of cases; trigger point injection in 60.1 percent, and epidural infusion of morphine with lidocaína in 69.3 percent of refractory cases. CONCLUSION: In patients with a post-laminectomy syndrome, postoperative pain was more severe than preoperative pain from a herniated disk. A miofascial component was found in most patients.