Does L4-L5 Pose Additional Neurologic Risk in Lateral Lumbar Interbody Fusion?

Objective: Lateral lumbar interbody fusion (LLIF) at the L4-L5 level is a controversial topic in the spine data. The aim of the present study was to compare the rate of nerve-related motor deficits in patients undergoing LLIF with and without L4-L5 involvement.

Methods: The clinical data from consecutive patients who had undergone LLIF from 2006 to 2016 at a single academic institution were retrospectively reviewed for new postoperative motor weakness of the quadriceps or tibialis anterior muscle. The patients were divided into 2 groups according to L4-L5 involvement. Regression analysis was performed to examine the association of LLIF at L4-L5 and the risk of new motor deficits.

Results: A total of 872 patients met inclusion criteria. The rate of new motor deficits at the 6-week postoperative visit in the L4-L5 group was 13.1%, which was significantly greater than that in the non-L4-L5 group at 5.5% (P < 0.001). After adjustment for potential confounders in multivariate logistic regression models, L4-L5 was still significantly associated with an increased risk of new motor deficit (odds ratio, 2.290; P = 0.008). Of the 686 patients with a minimum follow-up of 6 months, persistent nerve-related motor deficits at the last follow-up examination were recorded in 2.5% of the L4-L5 group and 0.4% of the non-L4-L5 group (P = 0.065).

Conclusions: The results from the present large study are in line with previous investigations reporting an initial increased risk of new motor deficits for LLIF performed at L4-L5. However, most new motor deficits were transient in nature and had resolved over time.