Summary: de Oliveira CMB, Sakata RK, Issy AM, Gerola LR, Salomão R -Cytokines and Pain. Background and objectives:Cytokines are necessary for the inflammatory response, favoring proper wound healing. However, exaggerated proinflammatory cytokine production can manifest systemically as hemodynamic instability or metabolic derangements. The objective of this review was to describe the effects of cytokines in pain.

Cytokines have an important role in pain through different mechanisms in several sites of pain transmission pathways.

Tissue and neuronal lesions result in sensitization of the nociceptors and facilitation of the central and peripheral nervous conduction.

Heart surgery is performed mainly via medium sternotomy, which results in significant postoperative pain and a non-negligible incidence of chronic pain. Effective pain control improves patient satisfaction and clinical outcomes. There is no clearly superior technique. It is believed that a combined multimodal analgesic regimen (using different techniques) is the best approach for treating postoperative pain, maximizing analgesia and reducing side effects.

CONTEXT AND OBJECTIVE: The role of immune response and proinflammatory cytokines in the pathogenesis of chronic pain has been of growing interest. In order to evaluate whether there is any association between disc herniation and elevated cytokine levels, we measured cytokine levels in patients with chronic low back pain and in healthy subjects. DESIGN AND SETTING:Analytical cross-sectional study at the Pain Clinic of Universidade Federal da Bahia (UFBA). METHODS:Cytokine levels were measured using the enzyme-linked immunosorbent assay (ELISA) technique on 23 patients with low back pain (G1) and on 10 healthy subjects (G2). RESULTS:The levels of tumor necrosis factor-alpha [TNF-alpha] (G1 = 5.6 ± 2.3 pg/ml; G2 = 1.6 ± 0.5 pg/ml; P = 0.01) and interleukin-6[IL-6] (G1 = 4.1 ± 3.0 pg/ml; G2 = 0.9 ± 0.4 pg/ml; P = 0.01) were higher in G1. There were no statistically significant differences in relation to interleukin-1 [IL-1] (G1 = 0.5 ± 0.3 pg/ml; G2 = 0.5 ± 0.1 pg/ml; P = 1) or soluble tumor necrosis factor receptor [sTNF-R] (G1 = 572 pg/ml ± 36; G2 = 581 ± 50 pg/ml; P = 0.87). CONCLUSION:The patients with chronic low back pain due to disc herniation presented higher levels of TNF-alpha and IL-6, but not of IL-1 or sTNF-R. RESUMO CONTEXTO E OBJETIVO:A função da resposta imunológica e das citocinas pró-inflamatórias na patogênese da dor crônica tem tido interesse crescente. Para avaliar se há correlação entre hérnia de disco e aumento de citocinas, foi medida a concentração de citocinas em pacientes com lombalgia crônica e em indivíduos sadios. TIPO DE ESTUDO E LOCAL: Estudo transversal analítico realizado na Clínica de Dor da Universidade Federal da Bahia (UFBA).MÉTODO: As concentrações de citocinas foram medidas pela técnica de ELISA (enzyme linked immunosorbent assay) em 23 pacientes com lombalgia (G1) e 10 sadios (G2). RESULTADOS:As concentrações de fator-alfa de necrose tumoral [TNF-alpha] (G1 = 5.6 ± 2.3 pg/ml; G2 = 1.6 ± 0.5 pg/ml; P = 0,01) e interleucina-6 [IL-6] (G1 = 4.1 ± 3.0 pg/ml; G2 = 0.9 ± 0.4 pg/ml; P = 0,01) foram maiores no G1. Não houve diferença estatisticamente significante para interleucina-1 [IL-1] (G1 = 0.5 ± 0.3 pg/ml; G2 = 0.5 ± 0.1 pg/ml; P = 1) e receptor solúvel do factor de necrose tumoral [sTNF-R] (G1 = 572 pg/ml ± 36; G2 = 581 ± 50 pg/ml; P = 0,87).CONCLUSÃO: Os pacientes com lombalgia crônica por hérnia de disco apresentam concentrações maiores de TNF-alpha e IL-6, mas não de IL-1 ou sTNF-R.

Postoperative persistent chronic pain is a complex and still unclear etiology entity, which interferes heavily in the life of the subject. Neuropathic pain resulting from surgical trauma is still the most common expression of this entity. Techniques to prevent nerve injury are recommended and should be used whenever possible. Despite efforts to understand and select risk patients, the management and prevention of this syndrome remain challenging and inappropriate.

Gabapentin, used before as well as before and after surgery, decreased pain severity and the need of analgesic supplementation.

Intravenous lidocaine can promote analgesia in surgical procedures, representing another alternative for the treatment of acute pain. Controlled studies with different surgical interventions could bring more information on this modality of analgesia.