Rectum and Anus 2 PDF

General Surgery MED 305 Coordinator: Dimitrios Ntourakis MD, PhD, FACS Rectum & anus GENERAL SURGERY – MED305 DIMITRIOS NTOURAKIS MD, PHD, FACS Objectives  Present the surgical anatomy and physiology of the rectum and the anal canal  Analyze the pathophysiology of the pelvic floor dysfunction, rec...

General Surgery MED 305 Coordinator: Dimitrios Ntourakis MD, PhD, FACS Rectum & anus GENERAL SURGERY – MED305 DIMITRIOS NTOURAKIS MD, PHD, FACS Objectives  Present the surgical anatomy and physiology of the rectum and the anal canal  Analyze the pathophysiology of the pelvic floor dysfunction, rectal prolapse and anal sphincter insufficiency as well as their clinical consequences  Describe the most common benign anorectal problems: hemorrhoids, anal fissures, anorectal abscesses and fistulas  Discuss the principles of diagnosis and treatment of rectal cancer and anal canal cancer Anatomy Rectum  Stool reservoir  From rectosigmoid junction to dentate line (12-15 cm)  3 curves (3 valves of Huston).  Vessels:  Arieries: superior (from IMA), middle (from internal iliac a), and inferior (from int pudental a) rectal a.  Veins: Superior (to portal system), middle and inferior (to systemic system) rectal veins Anatomy Anal canal  From dentate line to anal marge (3-4 cm)  Levator ani (puborectalis, pubococcygeous, iliococcygeus), internal sphincter, external sphincter  Sacral flexure, anorectal flexure (80o angle)  Gluteal skin, anoderm, anal transitional zone (dentate line), rectal mucosa  Superficial and deep venous plexuses (hemorrhoidal plexus) Physiology  Rectum holds 650-1200 mL of waste. Resting rectal pressure is 10 mm Hg  Continence   Puborectalis muscle (anorectal angle)  Internal sphincter (80%), external sphincter (20%) – resting pressure 60 mmHg  Hemorrhoids: cushion like sealing of the anal canal Sensory fibers in the levator ani sense rectum distention Physiology  Rectoanal inhibitory reflex:  Periodic internal sphincter relaxation, allowing the rectal contents to drop down into the anal canal where they are sampled by the sensitive anoderm.  After sampling, the external sphincter contracts and the contents are pushed back into the rectum.  Up to seven times daily during periods of rectal distention Advances in Diagnostic Assessment of Fecal Incontinence and Dyssynergic Defecation Anorectal symptoms  Pain  Bleeding  Anorectal mass  Altered bowel habit  Discharge (mucus, pus)  Tenesmus  Incontinence (gas, fluid, solid)  Rectal prolapse (mucosa, full thickness) Physical examination  Rectal examination  Digital examination  Anoscopy / proctoscopy  Sigmoidoscopy (rigid, flexible) Anal incontinence  Causes: obstetric injury, congenital anomalies, spinal cord injury, stretch induced injury of the pudental nerves, poor rectal compliance (IBD, radiation proctitis), overflow incontinence, iatrogenic injury.  Incontinence vs urgency vs soiling  Physical examination:   fistula, prolapse, hemorrhoids,  digital rectal examination for resting sphincter tone and contraction Incontinence score: Vayzay, Jorge – Wexner Anal incontinence  Work-up:  anal manometry  endoanal ultrasound  defecography (MRI)  pudental nerve motor latency test https://www.westernsydney.edu.au/gimotility/gi_disorders/anorectal_manometry Anal incontinence  Treatment:  Conservative - symptomatic  Surgery:  Sphnicteroplasty  artificial sphincter  sacral nerve stimulation  fecal diversion Pelvic floor dysfunction Pelvic floor dysfunction  Dysfunctional urinary and bowel evacuation, sexual dysfunction, pelvic pain syndromes  24% of women of advanced age  Clinical findings: constipation, straining, sense of incomplete evacuation, soiling  Work-up: colonoscopy, anal manometry, MRI defecography Rectal prolapse Rectal prolapse  Intussusception of the rectum due to abnormal fixation  Internal prolapse, mucosal prolapse, complete prolapse  Clinical findings: perianal mass, mucoid discharge, incomplete evacuation, incontinence  Surgical treatment for rectal prolapse: perineal and surgical procedures Hemorrhoids  Hemorrhoids = arteriovenous plexuses of the anal canal  Risk factors Obesity, constipation, pregnancy  External vs internal hemorrhoids (below – above dentate line)  Internal hemorrhoids at 3, 7 and 11 o’clock  Thrombosis of external hemorrhoids vs prolapse of internal hemorrhoids  Clinical findings:   Thrombosis=> pain, swelling, mass  Prolapse=> bleeding, pressure-like pain, soiling, itching Colonoscopy to investigate rectal bleeding Hemorrhoids  Treatment:  Conservative / symptomatic  Thrombosed hemorrhoids: surgical incision within 3 days  Internal:  rubber band ligation  stapled hemorrhoidopexy  doppler-guided hemorrhoidal ligation (DG-HAL)  excisional hemorrhoidectomy (Milligan – Morgan) Anal fissure  Anal fissure = tear in the anoderm  90% posterior midline  From trauma due to hard bowel movement  Spasm of the internal anal sphincter => pain after defecation  Chronic anal fissure = ischemic ulcer Anal fissure  Diagnosis: avoid rectal touch and anoscopy  Treatment:  Medical: laxatives, warm sitz baths, topical ointments with NTG, calcium channel blockers  Surgical: botulinium toxin injection to internal sphincter, lateral internal sphincterotomy Anorectal abscess Anorectal abscess  From anal crypt of the dentate line (cryptoglandular), Crohn’s disease (complex fistulas)  Location: perianal, ischiorectal, intersphincteric, supralevator  Clinical diagnosis. CT/MRI for intersphincteric or supralevator  Surgical drainage – risk of fistula (30-60%) Anorectal abscess & fistula Anorectal fistula  Types: intersphincteric, transphincteric, suprasphincteric, extrasphincteric  Diagnosis: perianal sinus with discharge. CT/MRI/EUS  Surgical treatment: fistulotomy, cutting seton, sphincter sparing techniques Pilonidal sinus  Sinuses in the natal cleft communicating with fibrous tracts containing hair  Acquired theory of origin  Clinical presentation: intermittent pain, swelling, purulent discharge, abscess Pilonidal sinus   Treatment:  Abscess: antibiotics, surgical drainage  Chronic disease:  excision with secondary healing  excision with primary closure  excision with plasty (Karydakis, Z-plasty, Limberg flap) Recurrence: incomplete excision, de novo hair ingrowth, persistence of midline wound (delayed healing) Pruritus ani  Intense itching of the perianal skin (3% of population)  Clinical presentation: burning -> itching, more severe at night, local inflammation, skin lichenification (chronic)  Causes:  90% idiopathic  10% anorectal disease, local irritants, perianal disease & infections, dermatologic conditions, systemic disease  Treatment: keep skin dry, skin barrier creams, brief trial of topical steroid  Frequent relapses Rectal cancer   Particularities of rectal cancer  Lymph node spread to inferior mesenteric and internal iliac nodes  Risk of infiltration of the anal sphincter  Infiltration of the fatty tissue around the rectum (mesorectum) Diagnosis: colonoscopy, CT scan (metastases), MRI + Endorectal US (local staging) Rectal cancer  Diagnosis: colonoscopy, CT scan (metastases), MRI + Endorectal US (local staging)  Treatment:  Surgery  Total mesorectal excision  abdominoperineal resection  Chemoradiation + surgery  Palliative chemoradiation Anal canal & anal margin neoplasms  Anal margin neoplasms:  Squamous cell carcinoma, basal cell carcinoma, verrucous carcinoma (giant condyloma)  Surgical treatment with wide local excision. If advanced or infiltrating the anal sphincter => irradiation / abdominoperineal resection Anal canal & anal margin neoplasms  Anal canal tumors  Epidermoid carcinoma  Slow growing mass => pain, bleeding  Diagnosis with rectoscopy  Radiation & chemotherapy (Nigro protocol)  Complete response 85% at 8 weeks after therapy Questions Conclusions  The anal canal has an internal anal sphincter (non-striated) and an external anal sphincter (striated). The puborectalis muscle forms a sling around the rectum that creates the anorectal angle. Damage to this mechanism causes fecal incontinence.  The most common causes of rectal pain are: hemorrhoidal thrombosis/strangulation, anal fissure, perianal abscess. Perianal abscess requires urgent surgical drainage or it may progress to sepsis. Hemorrhoids and anal fissure may respond to medical treatment or may require definitive surgical treatment.  Pilonidal sinuses are sinuses in the natal cleft communicating with fibrous tracts containing hair. It causes discomfort and if infected discharge of fluid. It may recur after surgical excision.  Cancer of the anal margin and the anal canal may infiltrate early the anal sphincter. Radiochemotherapy (Nigro protocol) has response rates of 80% and preserves the patient continence.  Rectal cancer gives lymphatic metastases to the portal and systemic lymph nodes. Treatment requires surgical resection of the rectum with removal of the fatty tissue around the rectum (total mesorectal excision). For advanced cancer chemoradiation gives good response rates and may be followed by surgical resection.