Surgery for extraforaminal lumbar disc herniation: a single center comparative observational study

BACKGROUND: Surgery on extraforaminal lumbar disc herniation (ELDH) is a commonly performed procedure. Operating on this type of herniation is known to come with more difficulties than on the frequently seen paramedian lumbar disc herniation (PLDH). However, no comparative data are available on the effectiveness and safety of this operation. We sought out to compare clinical outcomes at 1 year following surgery for ELDH and PLDH. METHODS: Data were collected through the Norwegian Registry for Spine Surgery (NORspine). The primary outcome measure was change at 1 year in the Oswestry Disability Index (ODI). Secondary outcome measures were quality of life measured with EuroQol 5 dimensions (EQ-5D); and numeric rating scales (NRSs). RESULTS: Data of a total of 1750 patients were evaluated in this study, including 72 ELDH patients (4.1%). One year after surgery, there were no differences in any of the patient reported outcome measurements (PROMs) between the two groups. PLDH and ELDH patients experienced similar changes in ODI (− 30.92 vs. − 34.00, P = 0.325); EQ-5D (0.50 vs. 0.51, P = 0.859); NRS back (− 3.69 vs. − 3.83, P = 0.745); and NRS leg (− 4.69 vs. − 4.46, P = 0.607) after 1 year. The proportion of patients achieving a clinical success (defined as an ODI score of less than 20 points) at 1 year was similar in both groups (61.5% vs. 52.7%, P = 0.204). CONCLUSIONS: Patients operated for ELDH reported similar improvement after 1 year compared with patients operated for PLDH.