Justin Tilan, Lindsay M. Andras, Mark D. Krieger, David L. Skaggs

March 2017, Volume 26, Issue 3, pp 619 - 622 Grand Rounds Read Full Article 10.1007/s00586-016-4853-1

First Online: 17 November 2016

Abstract[InlineMediaObject not available: see fulltext.]


To present a case of loss of motor-evoked potentials (MEPs) to the left foot in the supine position after a partial reduction and instrumented fusion from L4 to pelvis which was managed successfully without revision or removal of implants.


We report a patient with high-grade spondylolisthesis who demonstrated loss of motor-evoked potentials after posterior spinal fusion and transfer to supine position. The patient’s knees were flexed to 90° and signals were immediately restored. Systemic steroids were administered and circumferential fusion was delayed 21 days. Anterior-interbody cage was placed without complication.


She was discharged on post-operative day 2. At 7 months, she is pain free and doing well with plans to return to gymnastics completely.


Knee flexion can be instituted when encountering a neuromonitoring signal change following posterior spinal fusion for spondylolisthesis as a means to alleviate acute nerve stretch injury and may in some cases prevent the need to lessen the correction.

Level of evidence


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