The Effect of Previous Discectomy on Outcome After Lumbar Spinal Fusion Surgery

Introduction: Previous lumbar spinal surgery may predispose a poorer outcome after lumbar spinal fusion. We prospectively collected data from patients undergoing spinal fusion and defined two subsets. One group had undergone previous lumbar discectomy while the other group had not been previously operated upon.

Methods: In a multi-center (5 sites), non-randomized, prospective evaluation, 209 patients (range 18- 86 years, mean 53.4 years) undergoing either single-level (N=143) or two-level (N=65) lumbar fusion procedures were evaluated (SF-36 PCS, SF-36 MCS, ODI) 2yr postoperatively. Sixty (29%) had undergone prior discectomy (PD group), while 149 (71%) had no previous surgery (NS group).

Results: There were no significant group differences for demographics (age, gender, body mass index, tobacco use, insurance coverage) or intraoperative statistics (operative time, blood loss). Patients with a prior discectomy were more likely to be retired or disabled due to back problems (p<0 .001). Both groups demonstrated improvement from preoperative status in all three-outcome indices (P<0.05). Based upon SF-36 PCS, the NS group showed significant at 1 yr (_10.1 points) compared to PD (_ 4.9 (p<0.05). Year two results document a similar clinical 10.7 points versus _ 4.1 points), but lacked statistical significance (p="0.11)." suggesting inadequate sample size. MCS and ODI clear trend toward improved functional outcome patients not having prior surgery, however differences were observed. 26.7 years for only 21.9

Conclusions: All patients evaluated showed significant improvement after lumbar fusion surgery compared to their preoperative status. Those not having prior surgery showed greater improvement than those with a previous discectomy based upon SF-36 PCS in the first year. ODI scores demonstrated a trend at two years that favored the NS group.