Efficacy of intraoperative irrigation with artificial cerebrospinal fluid in chronic subdural hematoma surgery: study protocol for a multicenter randomized controlled trial
Authors: Nagashima Yoshitaka , Araki Yoshio , Nishida Kazuki , Kuramitsu Shunichiro , Wakabayashi Kenichi , Shimato Shinji , Kinkori Takeshi , Nishizawa Toshihisa , Kano Takahisa , Hasegawa Toshinori , Noda Atsushi , Maeda Kenko , Yamamoto Yu , Suzuki Osamu , Koketsu Naoki , Okada Takeshi , Iwasaki Masashige , Nakabayashi Kiyo , Fujitani Shigeru , Maki Hideki , Kuwatsuka Yachiyo , Nishihori Masahiro , Tanei Takafumi , Nishikawa Tomohide , Nishimura Yusuke , Saito Ryuta ,   Tokai Neurosurgical disorder Research Group CSDH Study investigators, Maesawa Satoshi , Izumi Takashi , Motomura Kazuya , Ito Eiji , Okumura Eriko , Ohka Fumiharu , Takeuchi Kazuhito , Nagata Yuichi , Yokoyama Kinya , Ishizaki Tomotaka , Kanamori Fumiaki , Fuse Yutaro , Sato Aya , Yukio Seki , Nagatani Tetsuya , Sakamoto Yusuke , Uda Kenji , Tsukada Tetsuya , Ishikawa Takayuki , Sasaki Hiroo , Jyunpei Ienaga , Sakai Yosuke , Watanabe Toru , Isozawa Yuichiro , Kato Nobuyasu , Kajita Yasukazu , Suzaki Noriyuki , Eguchi Kaoru , Ito Masashi , Goto Shunsaku , Ando Ryo , Yokoyama Hayato , Terao Kazuichi , Kawaguchi Naoto , Sugiyama Yu , Oyama Hitofumi , Kawaguchi Tomomi , Otsuka Takafumi , Osada Taiko , Matsuyama Tomoki , Hirayama Kengo , Takeda Kouki , Mizuno Shohei , Watanabe Kazuhiko , Nakamura Shigekazu , Ota Shinji , Kato Naoki , Ueno Masahiro , Sato Yusuke , Otawa Masato , Nakano Mizuki , Takido Yuhei , Okada Wataru , Sakuma Takashi , Yamamoto Shun , Iinuma Chihiro , Asai Takumi , Yamashita Yoshihiro , Muraoka Shinsuke , Nawa Shigeaki , Hamasaki Hajime , Fukui Takahiko , Suzuki Naoki , Takahashi Ikuo , Keisuke Ota , Kataoka Hirotada , Tamari Yosuke , Goto Tomoya , Seki Toshiki , Miyake Tomiyuki , Kato Takenori , Naito Takehiro , Mizuno Akihiro , Koketsu Yuta , Otake Takumi , Kageyama Akinori , Niwa Hirotaka , Oishi Hiroyuki , Yokoe Toshio , Takasu Shuntaro , Takemoto Masaya , Choo Jungsu , Ikezawa Mizuka , Sago Fumihiro , Somiya Daiki , Terano Mizuki , Doba Kohei , Shiraishi Daimon , Akahori Sho , Ishii Motonori , Fukaya Nobuhisa , Fukuoka Toshiki , Awaya Takayuki , Wakisaka Shoko , Tambara Masao , Shimizu Hiroyuki , Shinoda Satoshi , Muramatsu Yusuke , Endo Otone , Fujii Kentaro , Kawasaki Yiichi , Ono Takato , Hirayama Kento , Itagaki Yuya , Kurono Shuya , Ishiyama Jyunzo , Aoshima Chihiro , Sunohara Yuki , Aimi Yuri , Yoshida Mitsuhiro , Ishida Mamoru , Kimata Masayuki , Mizutani Hisashi , Hattori Kenichi , Wada Kentaro , Mamiya Takashi , Wakabayashi Masahiro , Hirose Toshiaki , Ito Risa , Ota Yusuke , Kubo Hiroaki , Noda Tomoyuki , Kawabata Teppei , Imai Tasuku , Oyama Takahiro , Hachiya Kei , Nishida Yasumasa 
Published: January 2024

Abstract
Background
The surgical techniques for treatment of chronic subdural hematoma (CSDH), a common neurosurgical condition, have been discussed in a lot of clinical literature. However, the recurrence proportion after CSDH surgery remains high, ranging from 10 to 20%. The standard surgical procedure for CSDH involves a craniostomy to evacuate the hematoma, but irrigating the hematoma cavity during the procedure is debatable. The authors hypothesized that the choice of irrigation fluid might be a key factor affecting the outcomes of surgery. This multicenter randomized controlled trial aims to investigate whether intraoperative irrigation using artificial cerebrospinal fluid (ACF) followed by the placement of a subdural drain would yield superior results compared to the placement of a subdural drain alone for CSDH.

Methods
The study will be conducted across 19 neurosurgical departments in Japan. The 1186 eligible patients will be randomly allocated to two groups: irrigation using ACF or not. In either group, a subdural drain is to be placed for at least 12 h postoperatively. Similar to what was done in previous studies, we set the proportion of patients that meet the criteria for ipsilateral reoperation at 7% in the irrigation group and 12% in the non-irrigation group. The primary endpoint is the proportion of patients who meet the criteria for ipsilateral reoperation within 6 months of surgery (clinical worsening of symptoms and increased hematoma on imaging compared with the postoperative state). The secondary endpoints are the proportion of reoperations within 6 months, the proportion being stratified by preoperative hematoma architecture by computed tomography (CT) scan, neurological symptoms, patient condition, mortality at 6 months, complications associated with surgery, length of hospital stay from surgery to discharge, and time of the surgical procedure.

Discussion
We present the study protocol for a multicenter randomized controlled trial to investigate our hypothesis that intraoperative irrigation with ACF reduces the recurrence proportion after the removal of chronic subdural hematomas compared with no irrigation.

Trial registration
ClinicalTrials.gov jRCT1041220124. Registered on January 13, 2023.