Study	Reason for exclusion
Allescher 2001	Not a RCT
Bansal 1996	Duplicate ‐ meeting abstract. Full paper later published
des Varannes 1999	Meeting abstract ‐ unable to contact author for more information
Gaudric 1996	Meeting abstract ‐ unable to contact author for more information
Jung 2012	Not a RCT ‐ meeting abstract
Linghu 2013	Meeting abstract ‐ unable to contact author for more information
Malekzadeh 2000	Duplicate ‐ meeting abstract. Full paper later published
Muehldorfer 1998	Duplicate ‐ meeting abstract. Full paper later published
Nebendahl 1998	Meeting abstract ‐ unable to contact author for more information
Zhou 2012	RCT published in Chinese Unable to contact author to obtain more information Key points from abstract: 80 patients randomly assigned to PD or BTX clinical symptoms and oesophageal kinematics of patients were evaluated before and 1 week, 1 month, and clinical outcomes were recorded during a follow up of 24 months clinical symptom scores and the lower oesophageal sphincter pressure were significantly improved in both treatment groups at 1 week and 1 month after therapy (P < 0.01) at 12 months, the clinical remission rates in PD group and BTX group were 73.2% and 61.5%, respectively