The Clinical Study Of The Effect Of MED On Serum Proinflammation Cytokine

Objective:This study was to investigate whether the Microendoscopic discectomy ( MED) technique had the minimally impact on systemic response , which had the minimal local invasive. By comparing variations in cytokine levels of patients following microendoscopic discectomy ( MED) versus open lumbar discectomy (OD) and observing surgical stress response, a quantitative comparison of surgical trauma result from MED and OD was performed through analyzing systemic immune response.Methods:40 patients who underwent procedure were prospectively randomized assigned to Microendoscopic discectomy group ( MED, N = 20) and open lumbar discectomy group (OD, N = 20) from April 2005 to June 2006. The serum sample of peripheral blood were collected before surgery and 1st, 3rd, 5th day after surgery. Concentrations of interleukin-6 (IL-6), interleukin-2 (IL-2) and tumor necrosis factor(TNF) were measured using an enzyme-linked immunosorbent assay( ELISA), Serum C-reactive protein (CRP) was measured at the same time interval. The following data were collected: length of skin incision, surgical time, intraoperative blood loss, the amount of removed disc, postoperative back pain by visual analogue scale, time needed before ambulation, and the length of hospital stay. The clinical outcomes were assessed using the modified MacNab criteria.Results :1.The MED had shorter size of skin incision (1.69±0.15cm VS 4.40±0.75cm, p<0.001) and less intraoperative blood loss (mean,62.5±15.34ml VS 77.0±27.74ml, p = 0.048), and there was no difference in other perioperative parameters. The patients-pain severity of the skin incision was less in MED group at 1st and 3rd day after surgery(P=0.007,P=0.03)than OD group. Time needed before ambulation and the length of hospital stay was shorter in MED group, and there was no difference in clinical outcomes between MED and OD group.2.No significant difference between the both groups in the preoperative serum concentration of TNF-α,IL-2,IL-6 and CRP(P >0.05) . TNF-αlevels increased significantly in both group(sMED P=0.016,OD P=0.001)at 1st day after surgery, and TNF-αincreased less significantly following MED than OD(P=0.049). TNF-αlevels decreased to preoperative state in both groups 3rd day after surgery. Plasma levels of IL-2 levels decreased in both groups(MED P=0.024,OD P=0.001) at 1 day after surgery, there was no significant difference between the 2 groups(P=0.098). IL-2 levels recovered to preoperative state in both groups 3rd day after surgery .IL-6 levels peaked at 1st day after surgery in both groups(MED P=0.001,OD P<0.001), and OD patients displayed a significantly greater postoperative rise in serum IL-6 (P=0.001).The rise in plasma levels remained 3rd day after surgery in both groups(MED P=0.031,OD P=0.021)and were more marked after OD than after MED procedure(P=0.004). IL-6 levels decreased to preoperative state in both groups at 5th day after surgery .CRP levels peaked at 1st day after surgery in both groups(MED P=0.001,OD P<0.001), and MED patients increased less significantly following MED than OD (P<0.001). The rise in plasma levels were more marked after OD than MED procedure(P=0.002)at 3rd day after surgery . CRP levels decreased to preoperative state in both groups at 5th day after surgery .3.Using Spearman rank correlation to analyze any relationship between serum CRP, TNF-α,IL-2,IL-6 concentrations and perioperative parameters,the results showed that there was a positive correlation between IL-6,CRP levels and intraoperative blood loss(IL-6 r = 0.456,P=0.003;CRP r = 0.377,P=0.018). There was no correlation between IL-6,CRP level and other perioperative parameters; and there was no correlation between TNF-α,IL-2 levels and all the perioperative parameters concerned in this study.Conclusions:1. MED has obviously advantages such as reducing the length of incision, postoperative local pain and blood loss, which showed the similar clinical outcomes with OD technique.2. MED has less magnitude of the proinflammation cytokines reaction compared with OD, and with a lower systemic surgical stress response which related to reducing the impact of immune system.3. Intraoperative blood loss were considered to be a key role in postoperative surgical stress response.