Timing of intraoperative neurophysiological monitoring (IONM) recovery and clinical recovery after termination of pediatric spinal deformity surgery due to loss of IONM signals

Travis S CreveCoeur; Rajiv R Iyer; Hannah E Goldstein; Mychael W Delgardo; Todd C Hankinson; Mark A Erickson; Sumeet Garg; David L Skaggs; Lindsay Andras; Benjamin C Kennedy; Patrick J Cahill; Lawrence G Lenke; Peter D Angevine; Benjamin D Roye; Michael G Vitale; Anil Mendiratta; Richard C E Anderson

doi:10.1016/j.spinee.2024.04.008

Timing of intraoperative neurophysiological monitoring (IONM) recovery and clinical recovery after termination of pediatric spinal deformity surgery due to loss of IONM signals

Spine J. 2024 Apr 11:S1529-9430(24)00169-4. doi: 10.1016/j.spinee.2024.04.008. Online ahead of print.

Authors

Travis S CreveCoeur¹, Rajiv R Iyer², Hannah E Goldstein³, Mychael W Delgardo⁴, Todd C Hankinson⁵, Mark A Erickson⁵, Sumeet Garg⁵, David L Skaggs⁶, Lindsay Andras⁷, Benjamin C Kennedy⁸, Patrick J Cahill⁹, Lawrence G Lenke¹⁰, Peter D Angevine⁴, Benjamin D Roye¹⁰, Michael G Vitale¹⁰, Anil Mendiratta¹¹, Richard C E Anderson¹²

Affiliations

¹ Columbia University, Department of Neurological Surgery; Och Spine Hospital; New York City, NY. Electronic address: Tc2682@cumc.columbia.edu.
² Division of Pediatric Neurosurgery, Department of Neurosurgery, University of Utah/Primary Children's Hospital, Salt Lake City, UT.
³ Division of Neurosurgery, Seattle Children's Hospital, Seattle, WA.
⁴ Columbia University, Department of Neurological Surgery; Och Spine Hospital; New York City, NY.
⁵ Children's Hospital Colorado, Aurora, CO.
⁶ Department of Orthopedic Surgery, Cedars-Sinai Medical Center, Los Angeles, Ca.
⁷ Jackie and Gene Autry Orthopedic Center, Children's Hospital Los Angeles; Ca.
⁸ Division of Neurosurgery, The Children's Hospital of Philadelphia, Philadelphia, PA.
⁹ Division of Orthopedic Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA.
¹⁰ Columbia University, Department of Orthopedic Surgery, New York, NY.
¹¹ Department of Neurology, Columbia University Medical Center, New York, NY.
¹² Department of Neurosurgery, New York University, New York, New York; NYU Neurosurgery Network, Ridgewood, NJ.

PMID: 38614157
DOI: 10.1016/j.spinee.2024.04.008

Abstract

Background context: Intraoperative neurophysiological monitoring (IONM) is used to reduce the risk of spinal cord injury during pediatric spinal deformity surgery. Significant reduction and/or loss of IONM signals without immediate recovery may lead the surgeon to acutely abort the case. The timing of when monitorable signals return remains largely unknown.

Purpose: The goal of this study was to investigate the correlation between IONM signal loss, clinical examination, and subsequent normalization of IONM signals after aborted pediatric spinal deformity surgery to help determine when it is safe to return to the operating room.

Study design/setting: This is a multicenter, multidisciplinary, retrospective study of pediatric patients (< 18 years old) undergoing spinal deformity surgery whose surgery was aborted due to a significant reduction or loss of IONM potentials.

Patient sample: Sixty-six patients less than 18 years old who underwent spinal deformity surgery that was aborted due to IONM signal loss were enrolled into the study.

Outcome measures: IONM data, operative reports, and clinical examinations were investigated to determine the relationship between IONM loss, clinical examination, recovery of IONM signals, and clinical outcome.

Methods: Information regarding patient demographics, deformity type, clinical history, neurologic and ambulation status, operative details, IONM information (e.g., quality of loss [SSEPs, MEPs], laterality, any recovery of signals, etc.), intra-operative wake-up test, post-operative neurologic exam, post-operative imaging, and time to return to the operating were all collected. All factors were analyzed and compared with univariate and multivariate analysis using appropriate statistical analysis.

Results: Sixty-six patients were enrolled with a median age of 13 years [IQR 11-14], and the most common sex was female (42/66, 63.6%). Most patients had idiopathic scoliosis (33/66, 50%). The most common causes of IONM loss were screw placement (27/66, 40.9%) followed by rod correction (19/66, 28.8%). All patients had either complete bilateral (39/66, 59.0%), partial bilateral (10/66, 15.2%) or unilateral (17/66, 25.8%) MEP loss leading to termination of the case. Overall, when patients were returned to the operating room two weeks postoperatively, nearly 75% (40/55) had monitorable IONM signals. Univariate analysis demonstrated that bilateral SSEP loss (p = 0.019), bilateral SSEP and MEP loss (p = 0.022) and delayed clinical neurologic recovery (p = 0.008) were significantly associated with having unmonitorable IONM signals at repeat surgery. Multivariate regression analysis demonstrated that delayed clinical neurologic recovery (> 72 hours) was significantly associated with unmonitorable IONM signals when returned to the operating room (p=0.006). All patients ultimately made a full neurologic recovery.

Conclusions: In children whose spinal deformity surgery was aborted due to intraoperative IONM loss, there was a strong correlation between combined intraoperative SSEP/MEP loss, the magnitude of IONM loss, the timing of clinical recovery, and the time of electrophysiological IONM recovery. The highest likelihood of having a prolonged postoperative neurological deficit and undetectable IONM signals upon return to the OR occurs with bilateral complete loss of SSEPs and MEPs.

Keywords: Motor Evoked Potentials; Pediatric Spinal Deformity, Intraoperative Neuromonitoring; Recovery; Signal Loss; Somatosensory Evoked Potentials.