TRANSDUODENAL OPERATION ON SPHINCTER OF ODDI, involving 1 or more of, removal of calculi, sphincterotomy, sphincteroplasty, biopsy, local excision of peri-ampullary or duodenal tumour, sphincteroplasty of the pancreatic duct, pancreatic duct septoplasty, with or without choledochotomy (Anaes.) (Assist.)