Introduction: The incidence of neurologic complications with spinal surgery for adolescent idiopathic scoliosis (AIS) has been reported to be 0.69%. This rare complication typically occurs during surgery or immediately postoperatively. We report the occurrence of a delayed neurologic deficit that presented 36 h after the initial surgery of a staged posterior spinal fusion for severe AIS. Case presentation: A 12-year-old girl with severe thoracolumbar AIS of 125° underwent attempted posterior spinal fusion from T2-L4. The case was complicated by a transient loss of transcutaneous motor evoked potentials (TcMEP) that resolved with an increase in the mean arterial pressure (MAP) and relaxation of curve correction with rod removal. The patient awoke with normal neurologic function. She had a transient decrease in MAP 36 h post-op and awoke on postoperative day #2 with nearly complete lower extremity paraplegia (American Spinal Injury Association [ASIA] Impairment Scale B). Emergent exploration and removal of the concave apical pedicles resulted in improvement of TcMEPs and return of function. Discussion: Delayed postoperative neurologic deficit is a very rare phenomenon, with only a few case reports in the literature to date. The delayed neurologic decline of our patient was likely secondary to a transient episode of postoperative hypotension combined with spinal cord compression by the apical concave pedicles. Close monitoring and support of spinal cord perfusion as well as emergent decompression are imperative in the setting of a delayed neurologic deficit. Further multicenter study on this rare occurrence is underway to identify potential causes and improve treatment.