[Traumatic responses following microendoscopic discectomy: clinical analysis of 44 patients]

To compare the traumatic responses following microendoscopic discectomy (MED) and open discectomy.

Forty-four patients with single level lumbar disk herniation underwent MED (Group A, n = 22) or open discectomy (Group B, n = 22). The intra-operational blood loss, duration of operation, intra-operative blood loss, and post-operational hospital stay were noted and the pain severity of incision was evaluated by visual analog scale (VAS). Serum levels of IL-6, C-reactive protein (CRP) and creatine kinase (CK) were measured before operation and 24 h and 48 h after operation. The clinical outcomes were evaluated by Oswestry disability index (ODI) before operation and 6 months after operation.

The intra-operative blood loss of Group A was 47.50 +/- 11.62 ml, significantly less than that of Group B (129.11 +/- 71.75 ml, P < 0.01), the duration of operation of Group A was 64.77 +/- 17.83, significantly shorter than that of Group B (78.18 +/- 24.32, P < 0.05). The postoperative hospital stay of Group A was 6.09 +/- 2.22 days, significantly shorter than that of Group B (8.73 +/- 3.53, P < 0.01). The scores of VAS 1, 2, and 3 days after the operation were all significantly lower than those of Group B (all P < 0.001). The rate of remarkable symptomatic improvement of Group A was 94.7%, not significantly different from that of Group B (94.4%, P > 0.05) The serum IL-6 showed no significant difference between these 2 groups pre-operationally, and peaked 24 h after operation and decreased 48 h after operation in both groups, returning to the pre-operational level in Group A. The IL-6 level 24 h and 48 h post-operationally of Group A was 31.6 +/- 9.88 pg/ml and 26.25 +/- 9.30 pg/ml respectively, both significantly lower than those of Group B (39.16 +/- 11.14 pg/ml and 32.55 +/- 8.83 pg/ml respectively, both P < 0.05) The serum CK showed no significant difference between these 2 groups pre-operationally, and peaked 24 h after operation and decreased 48 h after operation, but still higher than those before operation, in both groups. The serum CK 24 h and 48 h after operation of Group A were 167.91 +/- 51.85 and 131.50 +/- 52.70 U/L respectively, both significantly lower than those of Group B (401.55 +/- 108.86 and 260.32 +/- 64.98 U/L, both P < 0.01). The serum CRP level showed no significant difference between these 2 groups pre-operationally, and increased post-operationally, peaked 24 h after operation and then decreased in Group A, however, continued to increase in Group B. The serum levels of CRP 24 h and 48 h post-operationally of Group A were 12.68 +/- 7.10 and 10.77 +/- 5.25 pg/ml, both significantly lower than those of Group B (20.82 +/- 8.79 and 29.95 +/- 14.85 pg/ml, both P < 0.01). The clinical outcomes 6 months after operation of these two groups were all satisfying.

Both MED and open discectomy show good clinical outcomes in treatment of single level lumbar disk herniation, however, the less responses of serum IL-6, CRP, and CK show that the MED procedure is less traumatic.