Anal and rectal prolapse

• Rectal prolapse – eversion of rectum through the anus

Epidemiology

• Most common in infants, children and elderly
• More common in women

Etiology

• Chronic straining with defecation and constipation

Predisposing factors

• Pregnancy
• Previous surgeries
• Pelvic floor dysfunction due to diastasis of levator ani. Levator ani is a muscle group which is formed from
  • Pubovisceral muscles – 3 types
    • Pubovaginalis, puborectalis and puboanalis muscles
  • Iliococcygeus muscles
• Diarrhoea
• Old age

Classification and pathophysiology

Internal

• The rectal wall intussuscepts but doesn’t protrude
  • Looks like a funnel-shaped infolding of the upper rectal wall – usually occurs during defecation
• Rectum collapses but doesn’t exit the anus

Mucosal

• Partial protrusion, only the mucosal layer is prolapsed
• Loosening and stretching of the connective tissue that attaches the rectal mucosa to the rest of the rectal wall
• Often occurs alongside haemorrhoids

Complete

• Full thickness, circumferential, true intussusception of the rectal wall which protrudes through anus visibly
• Alexis Moschowitz theory
  • A complete prolapse is due to sliding herniation of the pouch of Douglas through the pelvic floor fascia
  • Due to chronic straining secondary to constipation, chronic cough, multiple pregnancies
• Broden and Snellman theory
  • A full thickness rectal intussusception starting 7.5 cm above the dentate line

Clinical features

• Tenesmus – continuous need to evacuate bowels
• Sensation of tissue protruding anus
• Mucus discharge or bleeding
• Incomplete evacuation
• History of constipation or straining

Investigations

• Complete prolapse is visibly obvious
• Colonic transit studies
• Manometry
• Pudendal nerve test
• Barium enema
• Colonoscopy
• CT – exclude neoplasm/diverticula

Treatment

• For mucosal/partial protrusion – phenol injection
  • Leads to aseptic inflammation and tethers the mucosal layer to the muscularis layer

Surgery

• Abdominal approach
  • Laparoscopic posterior mesh rectopexy
  • Wells rectopexy – fixation of rectum with prosthetic ring
• Perineal approach
  • Delormes operation – prolapsed lining of the rectal mucosa is removed and the underlying muscularis layer is plicated with sutures
  • Altemeier’s operation – rectosigmoidectomy with colonic anastomosis and plication of levator ani (to support the pelvic floor)