• Kazuyoshi Kobayashi, Shiro Imagama, Kei Ando, Go Yoshida, Muneharu Ando, Shigenori Kawabata, Kei Yamada, Tsukasa Kanchiku, Yasushi Fujiwara, Shinichirou Taniguchi, Hiroshi Iwasaki, Hideki Shigematsu, Nobuaki Tadokoro, Masahito Takahashi, Kanichiro Wada, Naoya Yamamoto, Masahiro Funaba, Akimasa Yasuda, Hiroki Ushirozako, Jun Hashimoto, Shinji Morito, Tsunenori Takatani, Toshikazu Tani, and Yukihiro Matsuyama.
• Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
• Spine. 2022 Jan 15; 47 (2): 172-179.

Study DesignProspective multicenter study.ObjectiveTo examine transcranial motor-evoked potential (Tc-MEP) waveforms in intraoperative neurophysiological monitoring in surgery for intradural extramedullary (IDEM) tumors, focused on the characteristics for cervical, thoracic, and conus lesions.Summary Of Background DataIDEM tumors are normally curable after resection, but neurological deterioration may occur after surgery. Intraoperative neurophysiological monitoring using Tc-MEPs during surgery is important for timely detection of possible neurological injury.MethodsThe subjects were 233 patients with IDEM tumors treated surgically with Tc-MEP monitoring at 9 centers. The alarm threshold was ≥70% waveform deterioration from baseline. A case with a Tc-MEP alert that normalized and had no new motor deficits postoperatively was defined as a rescue case. A deterioration of manual muscle test score ≥1 compared to the preoperative value was defined as postoperative worsening of motor status.ResultsThe 233 patients (92 males, 39%) had a mean age of 58.1 ± 18.1 years, and 185 (79%), 46 (20%), and 2 (1%) had schwannoma, meningioma, and neurofibroma. These lesions had cervical (C1-7), thoracic (Th1-10), and conus (Th11-L2) locations in 82 (35%), 96 (41%), and 55 (24%) cases. There were no significant differences in preoperative motor deficit among the lesion levels. Thoracic lesions had a significantly higher rate of poor baseline waveform derivation (0% cervical, 6% thoracic, 0% conus, P < 0.05) and significantly more frequent intraoperative alarms (20%, 31%, 15%, P < 0.05). Use of Tc-MEPs for predicting neurological deficits after IDEM surgery had sensitivity of 87% and specificity of 89%; however, the positive predictive value was low.ConclusionPoor derivation of waveforms, appearance of alarms, and worse final waveforms were all significantly more frequent for thoracic lesions. Thus, amplification of the waveform amplitude, using multimodal monitoring, and more appropriate interventions after an alarm may be particularly important in surgery for thoracic IDEM tumors.Level of Evidence: 3.Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.

16 keywords...

hide…