RESUMO
<p><b>OBJECTIVE</b>To investigate the change of serum levels of interleukin-6 (IL-6), C-reactive protein (CRP) and creatine kinase (CK) in patients undergoing microendoscopic discectomy (MED) and open discectomy.</p><p><b>METHODS</b>Forty-four patients with single level lumbar disk herniation were treated, either by MED (Group A, n equal to 22) or open discectomy (Group B, n equal to 22). Peripheral venous blood samples were taken before surgery and at 24 and 48 hours postoperatively. The operating time, intraoperative blood loss, postoperative hospital stay were recorded. The pain severity of incision was evaluated by visual analog scale after operation and the clinical outcome was evaluated by Oswestry disability index. Statistical comparison was performed by the analysis of variance and Student's t test.</p><p><b>RESULTS</b>The data showed that patients in Group A had a less intraoperative blood loss (P < 0.05), shorter operating length (P < 0.05), shorter postoperative hospital stay (P < 0.05) and less postoperative pain of incision than those in Group B. Serum levels of IL-6 (mean, 31.60 ng/L +/- 9.88 ng/L vs 39.16 ng/L +/- 11.14 ng/L, P < 0.05) and CK (mean, 167.91 U/L +/- 51.85 U/L vs 401.55 U/L +/- 108.86 U/L, P < 0.05) all get to the peak at 24 hours after operation and Group A with the response statistically less than Group B. Serum level of CRP peaked at 24 hours in Group A (mean, 12.68 mg/L +/- 7.10 mg/L vs 20.82 mg/L +/- 8.79 mg/L, P less than 0.05)and peaked at 48 hours after surgery in Group B (mean, 10.77 mg/L +/- 5.25 mg/L vs 29.95 mg/L +/- 14.85 mg/L, P < 0.05). The clinical outcomes of both groups were the same at 6 months after surgery.</p><p><b>CONCLUSIONS</b>Both MED and open discectomy have made good clinical outcomes, however, the less change of IL-6, CRP and CK after operation proves that MED procedure is less traumatic to patients than open discectomy.</p>