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Updated: Apr 17, 2026
Intra-Operative Neural Monitoring of Thyroid Surgery in a Porcine Model
Published on: February 11, 2019
Do the waveform transition patterns after intraoperative neurophysiological monitoring alerts indicate the
Wanyou Liu1, Junyin Qiu1, Yinkun Li1
1Department of Orthopedic Surgery, Division of Spine Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
Background Context:
Intraoperative neurophysiological monitoring (IONM) alerts during spinal deformity surgery require timely intervention, but the prognostic significance of different waveform transition patterns following these alerts remains inadequately characterized.
Purpose:
This study aimed to classify IONM waveform transition patterns after critical alerts and evaluate their association with immediate and long-term postoperative neurological outcomes.
Study Design:
A single-center retrospective cohort study.
Patient Sample:
A total of 37 out of 1994 patients (1.9%) who experienced significant IONM alerts during spinal deformity correction surgery between July 2015 and June 2022.
Outcome Measures:
Physiologic Measures: IONM waveform recovery (full, partial, or none). Functional Measures: Neurological status (no deficit, partial deficit, or complete paralysis) assessed immediately postoperation and during 24-month follow-up.
Methods:
Patients were categorized into 5 distinct IONM patterns based on waveform recovery dynamics and postoperative neurological status. Demographic, surgical, and radiographic factors were compared across groups. Due to the small sample size, analyses were primarily descriptive. Between-group comparisons were performed using Fisher's exact test for categorical variables.
Results:
A total of 5 waveform patterns were identified: Pattern A (full recovery, no deficits; 21.6%), B1 (partial recovery, no deficits; 13.5%), B2 (partial recovery, partial deficits; 24.3%), C1 (no recovery, partial deficits; 32.4%), and C2 (no recovery, complete paralysis; 8.1%). Exploratory analyses suggested that global kyphosis >90°, alerts during osteotomy, 3-column osteotomy, blood loss >3000 mL, and preoperative spinal cord abnormalities were more frequent in patients with irreversible alerts and deficits. At 2-year follow-up, 91.7% of patients with initial neurological deficits showed improvement, suggesting that IONM waveform recovery may be associated with favorable neurological prognosis.
Conclusions:
IONM waveform transition patterns following critical alerts demonstrate an significant association with postoperative neurological outcomes. Recovery trajectories varied across patterns: all Pattern B2 patients recovered within 6 months, while Pattern C patients showed gradual improvement over 24 months, with 91.7% of affected patients achieving favorable outcomes by 24-month follow-up, underscoring the importance of timely intervention during spinal deformity surgery.
