The unique characteristics of "upper" lumbar disc herniations

To compare the characteristics, presentation, and surgical outcome of patients with microdiscectomies at L1-L2 and L2-L3 with those we treated at L3-L4. We further sought to compare these results with those reported in the literature for discectomies at the L4-L5 and L5-S1 levels.

We reviewed the clinical data collected from 69 patients who had 72 L1-L2, L2-L3, and L3-L4 microdiscectomies performed from 1989 to 1999 at the New York University Medical Center. Patients who had surgery at L1-L2 or L2-L3 were grouped and compared with those treated at the L3-L4 level. Patients' charts were retrospectively reviewed at a mean of 12.9 months after surgery for presenting signs and symptoms, patient characteristics, and surgical outcome. Long-term follow-up via telephone interview was obtained at an average of 81.3 months after surgery.

In the L1-L2 + L2-L3 group, 58% of the patients had previous lumbar disc surgery, compared with only 10% of those in the L3-L4 group, and 20% in the L1-L2 + L2-L3 group required a fusion during the procedure compared with only 10% in the L3-L4 group. These differences are both statistically significant. The short-term chart review demonstrates that only 58% and 53% of patients in the L1-L2 + L2-L3 group were improved with regard to radicular and back pain, respectively, whereas those in the L3-L4 group reported 94 and 87% rates of improvement in the same categories, both highly statistically significant findings. The long-term follow-up confirmed a highly statistically significantly worse outcome in the L1-L2 + L2-L3 group, with only 33% of patients reporting an improvement in their economic or functional status, compared with an 88% rate of improvement in the L3-L4 group. The outcome of our patients with L3-L4 herniations was similar to that reported in the literature for herniations at L4-L5 and L5-S1.

Herniated discs at the L1-L2 or L2-L3 level are different entities from those at lower levels of the lumbar spine. The surgical outcome in terms of postoperative back and radicular pain is worse for herniated discs at L1-L2 and L2-L3 compared with those treated at L3-L4. Our patients with L1-L2 or L2-L3 surgically treated herniated discs were more likely to have had previous lumbar surgery and required a fusion more often than their counterparts with L3-L4 herniated discs.