Elsevier

World Neurosurgery

Volume 126, June 2019, Pages e432-e438
World Neurosurgery

Original Article
Quantitative Evaluation of Efficacy of Intraoperative Examination Monitor for Awake Surgery

https://doi.org/10.1016/j.wneu.2019.02.069Get rights and content

Background

When brain tumors are located near the language area, a test to assess language function is required. During the test, it is practical to display combined information obtained from all the equipment so that the surgeon can confirm the patient's response to the tasks. We developed the intraoperative examination monitor for awake surgery (IEMAS) mainly to combine all information so that the language function test could be performed efficiently. The IEMAS has proved to be useful in clinical settings; however, no quantitative evaluation has been performed. This study aimed to demonstrate the clinical usefulness of the IEMAS through comparison of cases with and without IEMAS use in language function test simulation.

Methods

The language function test simulator was created to eliminate any uncertain factors, such as symptoms, which vary among patients. Neurosurgeons participated in the test, and the usefulness of the IEMAS was investigated. We analyzed test duration and number of information exchanges between surgeon and examiner.

Results

Total test duration with IEMAS use was significantly shorter than without IEMAS use (116.1 ± 23.1 seconds vs. 147.8 ± 48.7 seconds; P < 0.02). The number of information exchanges between surgeon and examiner was significantly lower with IEMAS use than without IEMAS use (0.2 ± 0.6 times vs. 16.1 ± 15.6 times; P < 0.02).

Conclusions

We compared cases with and without IEMAS use. Total test duration decreased with IEMAS use, and number of information exchanges was reduced, thus demonstrating the usefulness of the IEMAS.

Introduction

The border between tumor and normal brain tissue is unclear because of the invasive nature of malignant brain tumors (gliomas), which commonly makes tumor resection difficult to achieve without affecting the peripheral normal tissue.1, 2 This is particularly true for lesions located in the vicinity of the language area of the brain. The clinical team identifies the language area before proceeding with resection of the tumor while retaining the language area function. Generally, language function testing occurs during awake craniotomy.3, 4, 5 In awake craniotomy, signs of functionality can be checked in real time while the tumor is being removed, facilitating the maximum possible removal of the tumor.6, 7, 8, 9 In intraoperative language function testing, an examiner, such as a speech therapist, assigns tasks to a patient while the surgeon applies an electrical stimulus around the affected area; for example, the patient may be asked to identify an image. The test helps detect the language function areas by monitoring the patient's response to the stimulus given.10

Sakurai et al. and Yoshimitsu et al. proposed and developed a device called the intraoperative examination monitor for awake surgery (IEMAS) (Figure 1).9, 11, 12, 13 The main function of the IEMAS is to combine and display all the video information in the operating room on 1 monitor. The IEMAS has a single arm that reaches the patient's face, a 3.2-inch liquid crystal display monitor that displays the task, and a small camera at the end of the arm to record the patient's facial expressions and voice. Another liquid crystal display monitor shows integrated video information from the surgical field, allotted tasks, the bispectral index (BIS) screen that displays the depth of anesthesia, the patient's facial expression, and surgical navigation images. The integrated information on the screen can be displayed on large monitors that have been installed in the operating room, enabling all members of the clinical staff to monitor the patient's status.14 As this information allows confirmation that nonresponse by the patient is due to insufficient wakefulness and prevents functional symptoms from being overlooked, it facilitates more effective intraoperative language function testing. Sakurai et al.11 reported on a patient who had stopped speaking after receiving electrical stimuli. However, the authors confirmed false-positive results in the speech area through the IEMAS monitor by observing the patient's ocular movement. Since 2004, the IEMAS has been used for language function testing as well as checking patients’ facial expression.15

Medical equipment, such as ADMENIC (Carina System Co., Ltd., Kobe, Japan; http://www.carinasystem.co.jp/en/product/medical/) and OPELIO (Seventh Dimension Design, Inc., Kobe, Japan; https://sdd.jp/en/products/opelio/), for the integrated display of aggregated information already exists. However, these devices do not cover intraoperative language function testing and are not capable of setting tasks or aggregating analogue video information and simultaneous recording. Furthermore, for the above-mentioned devices, no quantitative and scientific evaluation of their usefulness as information integration aggregation devices has been performed. This lack of quantitative assessment is due to the difficulty in performing tests to evaluate device efficiency under similar conditions, as the actual clinical settings of the state of the patient, the location of the lesion, and lesion size all vary. Furthermore, as introducing and removing such equipment during a surgical procedure would affect decision making, testing its effects in a real clinical environment is not possible. Therefore, this study aimed to develop a computer-simulated IEMAS and demonstrate its usefulness in language function testing through a comparison of cases with and without IEMAS simulator assistance in terms of parameters such as number of stimuli administered and test duration.

Section snippets

Materials and Methods

To quantitatively assess the usefulness of the IEMAS, it is necessary to standardize conditions for its evaluation. To accomplish this, we developed a language function testing simulator that could reproduce language function testing during awake craniotomy in reference to the state of the standard patient rather than the actual patient.

Results

Figure 5 shows the results for language function testing with and without IEMAS use. The following results were recorded: the number of electrical stimuli administered by the surgeon, language function testing duration (time between the pressing of the “start” and “end” buttons), average decision time for each electrical stimulation, and number of times information was exchanged between the surgeon and the examiner. During IEMAS use, electrical stimuli were administered 33.8 ± 7.6 times, the

Discussion

In the simulation language test experiment results using the language function test simulator (Figure 5), the total examination time was found to be significantly shorter with IEMAS use than without IEMAS use. The reason for this is that without IEMAS, the number of electrical stimuli increased, and subsequently the convulsions of patients increased. The number of times information was exchanged was significantly less with than IEMAS use without IEMAS use. This may be because the surgeon

Conclusions

To our knowledge, as yet there have been no reported quantitative evaluations carried out with the aim of demonstrating the usefulness of information-integrating equipment. In this study, we set the patient’s status as certain conditions by developing a simulator (language function testing simulator) that is capable of reproducing language function testing during awake craniotomy. This enabled an evaluation focused solely on the information integration aggregation equipment itself using data

Acknowledgments

We thank Dr. Takashi Maruyama, Dr. Masayuki Nitta, Dr. Takayuki Yasuda, and Dr. Syunsuke Tsuzuki of Tokyo Women's Medical University for assistance with the experiment and Mr. Hidetsugu Asano and Mr. Yusuke Fujii for advice regarding this study.

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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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