Patients will undergo anal physiological assessment and will then be randomized to either treatment arm. The first 12 weeks they will be optimized in the conservative treatment of their bowel function before beginning active treatment with TAI or PNE. After 8 and 4 weeks respectively, the treatment will stop and they will have a period of 4 weeks back on optimized conservative treatment before beginning active treatment in the other active arm.
Detailed records of bowel, micturition and sexual function and QoL will be obtained at regular intervals during the entire trial fase.
