Rectal prolapse and anal sphincter.

I have faced chronic constipation .It was diagnosed by a psychiatrist somatic disorder with ibs c . taking antidepressants releif 2 to 3 years on after problem repeat. starting relief with laxatives on after laxatives does not work and become chronic even with enima does not releif. sink water too much time and only reverse only water. anorectal manometry, floral defecography and colonic transit study and colony tests have done. In last ten years 4 times colonoscopy test not found any thing. Anorectal manometry found sphincter muscle stretching and defecography found rectal prolapse. biofeedback does not releif . psychiatrist said some cases muscle stretching pattern is continue , and it was cure by surgical procedure, I am consult a proctologist he said first rectal prolapse surgery, on after if not relief from constipation then going to sphincter muscle surgery. But one risk about sphincter surgery in old age motion leakage problem maybe. even gases canot release anus,