Alert Timing and Corresponding Intervention With Intraoperative Spinal Cord Monitoring for High-Risk Spinal Surgery

Abstract

Study Design. Prospective multicenter study. Objective. To analyze the incidence of intraoperative spinal neuromonitoring (IONM) alerts and neurological complications, as well as to determine which interventions are most effective at preventing postoperative neurological complications following IONM alerts in high risk spinal surgeries. Summary of Background Data. IONM may play a role in identifying and preventing neural damage; however, few studies have clarified the outcomes of intervention after IONM alerts. Methods. We analyzed 2867 patients who underwent surgery for high risk spinal pathology using transcranial electrical motor-evoked potentials from 2010 to 2016. The high-risk spinal surgery cases consisted of 1009 spinal deformity cases, 622 cervical ossification of posterior longitudinal ligament (OPLL) cases, 249 thoracic-OPLL cases, 771 extramedullary spinal cord tumor cases, and 216 intramedullary spinal cord tumor (IMSCT) cases. We set a 70% amplitude reduction as the alarm threshold for transcranial electrical motor-evoked potentials and analyzed the outcomes of the interventions following monitoring alerts and postoperative neurological deficits. Results. The true positive, false positive, true negative, false negative, and rescue cases of IONM comprised 126, 234, 2362, 9, and 136 cases, respectively. Most alerts and interventions occurred during correction and release in deformity cases, posterior decompression and dekyphosis in OPLL cases, and tumor resection and surgery suspension with steroid injection in spinal cord tumor cases; however, individual interventions varied. The rescue rates (number of patients rescued with intervention after IONM alert/number of true positive cases plus rescue cases) for deformity, cervical-OPLL, thoracic--OPLL, extramedullary spinal cord tumor, and IMSCT cases were 61.4% (35/57), 82.1% (32/39), 40% (20/50), 52.5% (31/59), and 31.6% (18/57), respectively. Conclusion. Our prospective multicenter study identified potential neural damage in 9.5% of cases and 52% rescue cases using IONM. Although the rescue ratios for t-OPLL and IMSCT were relatively low, appropriate intervention immediately after an IONM alert may prevent neural damage even in high-risk spinal surgeries. Level of Evidence: 3

Ossification of the Posterior Longitudinal Ligament: Surgical Approaches and Associated Complications

“…Changes in somatosensory evoked potential (SEP) can signal impending spinal cord injuries, and Epstein et al [69] showed a reduction in neurologic deficits associated with SEP monitoring. Additionally, a recent multicenter analysis by Yoshida et al [77] found a rescue rate of 82.1% when IONM was used during surgical correction of cervical OPLL.…”

A rare intraoperative spinal cord injury caused by thoracic 8 nerve root interruption during posterior vertebral column resection surgery for severe congenital kyphoscoliosis: a case report

“…After those series of interventions, the IOM signals partial recovery from the lowest point. Therefore, after the significant high-risk surgical points it was very necessary to continue observing the IOM signals for a few minutes, and appropriate timely interventions were very useful in restoring the signals [7][8][9].…”

Responding to Intraoperative Neuromonitoring Changes During Pediatric Coronal Spinal Deformity Surgery

“…Repeat bilateral loss of MEP signal was the result of inadequately addressing the spinal cord perfusion deficiencies prior to obtaining the desired correction. Yoshida et al, 8 in a prospective multicenter review, observed 57 alerts in 1009 deformity cases occurring with rod rotation (n ¼ 21), pedicle screw insertion (n ¼ 7), osteotomy closing (n ¼ 6), compression, distraction, cantilever, or translation (n ¼ 10), decompression (n ¼ 3), and root sacrifice (n ¼ 3). There were 6 other significant drops in signal that they state were unrelated to the surgery.…”