Localization and symptoms associated with removal of negative motor area during awake surgery

Abstract

Background

In awake surgery, cortical mapping may identify the negative motor area (NMA). However, since speech arrest occurs regardless of whether the NMA or the frontal language area (FLA) is stimulated, the presence of speech arrest alone does not distinguish the NMA from the FLA. Furthermore, the exact location and function of the NMA is not well understood. The purpose of this study was to more accurately locate the NMA in a group of cases in which the NMA and FLA could be identified in different brain gyri, and to describe symptoms in cases in which the NMA was removed.

Methods

There were 18 cases of awake surgery at our institution between 2000 and 2013 in which cortical stimulation allowed identification of FLA and NMA in separate brain gyri. In these cases, the pre- and post-removal mapping results were projected onto a 3D model postoperatively. We investigated the symptoms and social rehabilitation in a case in which the tumour invaded the same brain gyrus as the NMA and the NMA had to be resected in combination with the tumour.

Results

In cases where the NMA and FLA could be identified in different brain gyri, NMA was localized inferior to the precentral gyrus in all cases. In four cases where NMA was removed with the tumour, apraxia of speech was observed during the surgery; the same symptoms persisted after it, but it improved within a few months, and the patients were able to return to work.

Conclusion

In cases where NMA and FLA could be identified separately by awake mapping, the NMA was commonly localized inferior to the precentral gyrus. When NMAs were resected in combination with tumour invasion, they did not lead to serious, long-term complications.

Keywords:

• Negative motor area
• awake craniotomy
• functional mapping
• glioma
• apraxia of speech

Acknowledgements

The authors wish to thank Dr. Takashi Komori, Department of Pathology, and Mr. Takashi Sakayori, a laboratory technician at Tokyo Women’s Medical University, for their crucial contributions to the pathologic diagnoses. We also wish to extend special thanks to Ms. Satoko Fukuchi and Ms. Reiko Ishihara for their intraoperative mapping. We would like to thank Editage (www.editage.com) for English language editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethical approval

All procedures and analyses conducted in this study were approved by the Ethics Committee of our institution and were conducted in accordance with the tenets of the Declaration of Helsinki.

Informed consent

Due to the retrospective nature of the study, the institutional review board of the hospital waived the requirement for informed consent.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Notes on contributors

Shunsuke Tsuzuki

Shunsuke Tsuzuki is an Assistant Professor at the Department of Neurosurgery, Tokyo Women’s Medical University, where he specializes in clinical and research aspects of malignant brain tumours. His work involves chemotherapy and radiotherapy, as well as surgery.

Yoshihiro Muragaki

Yoshihiro Muragaki is a professor at the Institute for Advanced Biomedical Sciences, Tokyo Women’s Medical University, specializing in malignant brain tumours. His work involves medical-engineering collaboration. He received an award from the Terumo Life Science Foundation for the development of SCOT, a smart treatment room that will realize precision-guided therapy in 2022.

Takashi Maruyama

Takashi Maruyama is an Adjunct Lecturer at the Department of Neurosurgery, Tokyo Women’s Medical University. He specializes in the surgical treatment of malignant brain tumours and is well versed in awake surgery.

Taiichi Saito

Taiichi Saito is a Lecturer in Neurosurgery at Tokyo Women’s Medical University. He specializes in surgery for malignant brain tumours and has authored many papers on awake surgery and intraoperative monitoring.

Masayuki Nitta

Masayuki Nitta is a Lecturer at the Institute for Advanced Biomedical Sciences, Tokyo Women’s Medical University. He specializes in surgery and basic research on malignant brain tumours and pathological diagnosis. He is in charge of intraoperative flow cytometry and rapid genetic diagnosis.

Manabu Tamura

Manabu Tamura is an Associate Professor at the Institute for Advanced Biomedical Sciences, Tokyo Women’s Medical University. He specializes in medical-engineering collaboration and preoperative simulation of the relationship between tumour and brain surface location.

Takakazu Kawamata

Takakazu Kawamata is the Chief Professor of Neurosurgery at Tokyo Women’s Medical University. He specializes in the surgical treatment of benign brain tumours and cerebrovascular disorders.