EUS-guided celiac plexus neurolysis by using highly viscous phenol-glycerol as a neurolytic agent (with video) Hirotoshi Ishiwatari, MD, PhD, 1 Tsuyoshi Hayashi, MD, PhD, 1 Makoto Yoshida, MD, PhD, 1 Michihiro Ono, MD, 1 Tsutomu Sato, MD, PhD, 1 Koji Miyanishi, MD, PhD, 1 Yasushi Sato, MD, PhD, 1 Rishu Takimoto, MD, PhD, 1 Masayoshi Kobune, MD, PhD, 1 Hiroyuki Masuko, BPharm, 2 Atsushi Miyamoto, MP, PhD, 2 Tomoko Sonoda, DDS, PhD, 3 Junji Kato, MD, PhD 1 Sapporo, Japan EUS-guided celiac plexus neurolysis (EUS-CPN) is considered to be a reliable treatment for cancer-related pain. However, inadequate distribution of the neurolytic agent to the celiac plexus (CP) has been presumed to contribute to the failure of pain relief. Indeed, it has been reported that the distribution of the neurolytic agent to only the left side of the celiac artery (CA) (as assessed by CT) is a significant predictor of negative response to EUS- CPN. 1 Generally, the injected neurolytic agent in EUS-CPN is more likely to flow into the left side of the CA. Further, it often spreads extensively beyond the CP and throughout the retroperitoneal cavity. 1,2 These tendencies probably relate to the left lateral decubitus position during the pro- cedure and the supine position after the procedure, which allow the neurolytic agent to spread extensively by gravity, preventing it from remaining near the CA. We hypothe- sized that a highly viscous neurolytic agent would remain around the CP and provide better pain relief. Ethanol and phenol are the neurolytic agents commonly used in CPN. Although they permanently destroy the CP, they have low viscosities. 3 A representative highly viscous neurolytic agent is glycerol, which has been recommended for blocking the gasserian ganglion in trigeminal pain. 4 Glycerol is not suitable for CPN treatment because its destructive effect is reversible. Nonetheless, potentially it provides a clinically approved viscous substrate for phenol and ethanol delivery. 4 Accordingly, we examined the feasi- bility of mixing these agents with glycerol to increase their viscosities. Ethanol is a thin liquid that is used for CPN at a concen- tration of O50%, which is necessary to provide reliable neurodestructive effects. 5 Hence, this mixture is not suit- able for our purpose. Phenol is generally injected at a con- centration of 6% to 7%. 6,7 Because phenol’s pure form is a 100% crystalline solid that is highly soluble in glycerol and water, this concentration can be maintained even when mixed with O50% glycerol. 3,6,7 Therefore, we applied this mixture (phenol-glycerol) to EUS-CPN. The goal of this intervention-based case series was to investigate the feasi- bility of EUS-CPN by using highly viscous phenol-glycerol. PATIENTS AND METHODS Study design In this prospective case series, we monitored pain relief, the distribution of phenol-glycerol, and the safety of EUS-CPN by using a mixture of 7% phenol and 60% glycerol. After we obtained approval from the Institutional Review Board of Sapporo Medical University, the study was con- ducted at Sapporo Medical University Hospital. All patients provided written informed consent for the procedure and data collection. Patient eligibility Each patient was evaluated through a medical history, physical examination, pain assessment, blood examination, and dynamic contrast-enhanced CT before the procedure. The inclusion criteria were as follows: (1) unresectable up- per abdominal cancer diagnosed on dynamic contrast- enhanced CT, (2) pathologically confirmed malignancy, (3) upper abdominal pain with a numeric rating scale score of R4 (11-point numeric rating scale: 0 Z no pain, 10 Z worst possible pain), (4) performance status of 0 to 3 on the Eastern Cooperative Oncology Group Scale, and (5) age R20 years. The exclusion criteria were as follows: (1) history of CPN, (2) prolongation of prothrombin time Abbreviations: CA, celiac artery; CP, celiac plexus; CPN, celiac plexus neurolysis; EUS-CPN, EUS-guided CPN. DISCLOSURE: All authors disclosed no financial relationships relevant to this article. This video can be viewed directly from the GIE website or by using the QR code and your mobile de- vice. Download a free QR code scanner by searching “QR Scanner” in your mobile device’s app store. Copyright ª 2015 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 http://dx.doi.org/10.1016/j.gie.2014.10.031 Received August 27, 2014. Accepted October 23, 2014. Current affiliations: Department of Medical Oncology and Hematology, Sapporo Medical University, Sapporo (1), Department of Hospital Pharmacy, Sapporo Medical University, Sapporo (2), Department of Public Health, Sapporo Medical University, Sapporo (3). Reprint requests: Hirotoshi Ishiwatari, MD, PhD, Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, 060-8543 Sapporo, Japan. www.giejournal.org Volume 81, No. 2 : 2015 GASTROINTESTINAL ENDOSCOPY 479 Ishiwatari et al Phenol-glycerol as a neurolytic agent for EUS-guided celiac plexus neurolysis