Efficacy and safety of botulinum toxin injection for occipital neuralgia: a systematic review. - Siahaan, Yusak Mangara Tua; Pradhana, Tasya Meidy; Arjuna, Yang Yang Endro; Hartoyo, Vinson; Purnomo, Alexander Erick; Darmawan, Rosaria Oktafiani (Anaesthesia, Pain & Intensive Care, 2026)