Current Status and Future Objectives of Surgical Therapies for Epilepsy in Japan

Status of epilepsy care delivery and referral in clinics, hospitals, and epilepsy centers in Japan: A nationwide survey

OBJECTIVE

Collaboration among medical facilities is crucial to deliver comprehensive epilepsy care to a diverse and large population of people with epilepsy. We conducted a survey among medical facilities of various sizes throughout Japan to investigate the status of epilepsy care delivery, functioning, and referral.

METHODS

With the cooperation of the Japan Neurological Society (1428 facilities), Japanese Neurosurgical Society (3489 specialists), and Epilepsy Care Network (948 facilities), a questionnaire was mailed to 5865 locations that provide epilepsy care in Japan. The facilities were classified into clinics (19 beds or less), small hospitals (SH, 20-199 beds), large hospitals (LH, 200 beds or more), and epilepsy centers (EC). The status of epilepsy care delivery, functioning, and referral was compared among the four groups.

RESULTS

Responses were received from 1014 facilities (17.3% response rate). After excluding duplicate responses, 957 facilities were analyzed (394 clinics, 149 SH, 388 LH, 26 EC). EC responded "manageable" in more items of epilepsy care functions in general, especially those related to epilepsy surgery, compared to LH with similar facility size. However, EC responded being less manageable in psychiatric service (61.5%), dietary therapy (46.2%), rehabilitation (53.8%), and patient employment support (61.5%). The percentage of facilities that responded "always able to refer" was highest in clinics (67.6%) and the lowest in EC (40%). Referral difficulties were more commonly encountered in EC, and less common in clinics. In EC, the most common reason for inability to refer was patient or family refusal (64%).

SIGNIFICANCE

We have clarified the epilepsy care delivery, functioning, and referral in facilities of various sizes in Japan. This study highlights the issues of downward referral and patient stagnation in EC, which have not received much attention.

PLAIN LANGUAGE SUMMARY

A nationwide survey of healthcare facilities ranging in size from small clinics to large hospitals in Japan examined medical care delivery and patient referrals related to epilepsy. Compared to other facilities, epilepsy centers provided a variety of medical services to people with epilepsy but were inadequate in addressing psychiatric symptoms, providing dietary therapy, rehabilitation, and patient employment support. Referrals from epilepsy centers to other medical facilities were often refused by patients and their families. This results in patient crowding at epilepsy centers.

Intraoperative nerve stimulation during vagal nerve stimulator placement

Background

Vagal nerve stimulation (VNS) is a palliative treatment for refractory epilepsy and intraoperative nerve stimulation is applied to the vagal and other nerves to prevent electrode misplacement. We evaluated these thresholds to establish intraoperative monitoring procedures for VNS surgery.

Methods

Forty-six patients who underwent intraoperative nerve stimulation during VNS placement were enrolled. The vagal nerve and other exposed nerves were electrically stimulated during surgery, and muscle contraction was confirmed by electromyography of the vocal cords and visual recognition of cervical muscle contraction. The nerve thresholds and the most sensitive parts of the vagal nerve were analyzed retrospectively.

Results

The stimulation of vagal nerves induced vocal cord responses in all 46 patients; the median thresholds of the most sensitive parts and all parts were 0.2 mA (range: 0.05-0.75 mA) and 0.25 mA (range: 0.15-1.5 mA), respectively. The medial middle region was identified as the most sensitive part of the vagal nerve in the majority of participants (82.5%). In 11 patients, other cervical nerves were stimulated and sternohyoid muscle contraction was induced with a median threshold of 0.35 mA (range: 0.1-0.7 mA) in eight patients, while sternocleidomastoid muscle contraction was induced with a median threshold of 0.2 mA (range: 0.1-0.2 mA) in three.

Conclusion

Intraoperative stimulation of vagal nerves induces vocal cord responses with locational variations, and the middle part stimulation could minimize the stimulus intensities. The nerves innervating the sternohyoid and sternocleidomastoid muscles may be exposed during the procedure. Knowledge of these characteristics will enhance the effectiveness of this technique in future applications.

Clinical Impacts of Stereotactic Electroencephalography on Epilepsy Surgery and Associated Issues in the Current Situation in Japan

Stereotactic electroencephalography (SEEG) is receiving increasing attention as a safe and effective technique in the invasive evaluation for epileptogenic zone (EZ) detection. The main clinical question is whether the use of SEEG truly improves outcomes. Herein, we compared outcomes in our patients after three types of intracranial EEG (iEEG): SEEG, the subdural electrode (SDE), and a combined method using depth and strip electrodes. We present here our preliminary results from two demonstrative cases. Several international reports from large epilepsy centers found the following clinical advantages of SEEG: 1) three-dimensional analysis of structures, including bilateral and multilobar structures; 2) low rate of complications; 3) less pneumoencephalopathy and less patient burden during postoperative course, which allows the initiation of video-EEG monitoring immediately after implantation and does not require resection to be performed in the same hospitalization; and 4) a higher rate of good seizure control after resection. In other words, SEEG more accurately identified the EZ than the SDE method. We obtained similar results in our preliminary experiences under limited conditions. In Japan, as of August 2022, dedicated electrodes and SEEG accessories have not been approved and the use of the robot arm is not widespread. The Japanese medical community is hopeful that these issues will soon be resolved and that the experience with SEEG in Japan will align with that of large epilepsy centers internationally.