Study design: Retrospective case series.
Objective: To report on the rare finding of motor deficits contralateral to the transpsoas approach in patients who underwent lateral lumbar interbody fusion (LLIF).
Summary of background data: Although sensorimotor deficits occurring ipsilaterally to a transpsoas approach have more fully been elucidated, there seems to be a paucity of data on motor deficits contralateral to an LLIF approach.
Methods: The electronic medical records and radiographical studies of 244 patients who underwent LLIF at a single institution between 2006 and 2009 were retrospectively reviewed for reports on motor deficits contralateral to the surgical approach.
Results: Of the patients reviewed, 2.9% (7/244) presented with a postoperative contralateral motor deficit, the most severe of which was a 1/5 weakness of the quadriceps muscle. An average of 3 levels (range: 2-4) was fused in 7 patients who developed a contralateral motor deficit, and in 3 of the 7 patients, an anterior lumbar interbody fusion (ALIF) was performed in addition to the LLIF. At 1 year follow-up, 3 patients presented with complete resolution of their muscle weakness, 1 patient still had mild weakness, 1 patient had decreased range of motion in the affected joint, and 1 patient had a 2/5 foot drop. One patient was lost to follow-up.
Conclusion: These data are among the largest reports of contralateral motor deficits after LLIF. Among possible underlying mechanisms are entrapment of the contralateral nerve root through translational correction of spondylolisthesis, front-to-back misalignment of the cage resulting in contralateral nerve root impingement, pressure on the contralateral peroneal nerve during positioning, and overdistraction neurapraxia when using ALIF at L5-S1 concomitantly. Awareness of the possibility of this rare complication can play an important role in surgical consideration and preoperative patient counseling.
Level of evidence: 4.