#422 Neurologic Complications in Extreme Lateral Interbody Fusion (XLIF): A Comparative Analysis of Levels L2-3, L3-4, and L4-5

General Session: Lateral Interbody Fusion

Presented by: W. Smith

Author(s):

W.D. Smith (1), (2)

(1) University Medical Center of Southern Nevada, Neurosurgery, Las Vegas, NV, USA
(2) Western Regional Center for Brain & Spine Surgery, Neurosurgery, Las Vegas, NV, USA

Abstract

Introduction: Studies of relevant neural anatomy to the lateral approach have suggested that motor nerves of the lumbar plexus are often at risk of injury, especially at L4-5. Reported complication rates of neural injury with the extreme lateral interbody fusion (XLIF) approach, however, are low (0.7%-2.9%) due to the adherence to advanced neuromonitoring systems integrated with the procedure. The objective of this study was to examine neural (sensory and motor) deficit rates following XLIF.

Methods: Demographic, treatment, and complication data were collected retrospectively in single-level cases of L2-3, L3-4, or L4-5 lumbar disease treated with XLIF at a single institution. A total of 252 patients were treated from 2004 through 2008. Average age was 58.5 years and 56.7% were female. L2-3 was treated in 31 cases (12.3%), with L3-4 treated in 64 (25.4%) and L4-5 in 157 (62.3%) cases. Pedicle screws were used in 70.2%, anterolateral plating in 7.9%, and no supplemental fixation was used in 21.8% of cases.

Results: In total, 25 (9.9%) patients experienced postoperative anterior thigh/groin sensory changes (numbness, tingling), 30 (11.9%) patients experienced anterior thigh/groin pain, and 2 (0.8%) patients exhibited new lower extremity motor deficits (foot drop) following XLIF. Thigh/groin sensory changes resolved completely in 76% of patients, improved in 20%, and were unchanged in 4% of cases by 12 weeks postoperative. Anterior thigh/groin pain completely resolved in 83.3%, improved in 13.3%, and no change occurred in 3.3% of cases by 12 weeks postoperative. Both postoperative motor deficits resolved, one at 12 weeks, the other at 12 months.

When analyzed by level, 62.3% (118) of cases were treated at L4-5 and these patients experienced only 56% (14) of the thigh sensory events, 53% of the thigh pain events, and 100% (2) of the postoperative motor deficits. Of the 64 (25.4%) L3-4 patients, 9 patients experienced thigh sensory changes (36% of total thigh sensory change patients) and 9 patients experienced postoperative thigh pain (30% of total thigh pain patients), without any motor deficits observed. Finally, of those 31 (12.3%) patients treated at L2-3, they included 8% (2) of the thigh sensory change patients and 17% (5) of the thigh pain patients without any motor deficits.

Conclusions: Thigh/groin sensory changes were relatively well distributed between L2-3, L3-4, and L4-5. Despite the majority of cases occurring at L4-5, a relatively low motor injury rate was observed (0.8%) even with more posterior docking for interbody spacer placement. Sensory and painful thigh/groin symptoms, however, are likely caused by irritation of the genitofemoral nerve, which runs on the anterior half of the lateral disc space from L2-5. In the case where a more anterior docking approach is used to avoid the lumbar plexus, this theoretically increases the likelihood of injury to the genitofemoral nerve which cannot be monitoring using electromyography.