COLON and
RECTUM
OUTLINE
ANATOMY AND PHYSIOLOGY
CLINICAL EVALUATION
GENERAL SURGICAL CONSIDERATIONS
INFLAMMATORY BOWEL DISEASE
DIVERTICULAR DISEASE
ADENOCARCINOMA AND POLYPS
INHERITED COLORECTAL CANCER
OTHER NEOPLASM AND BENIGN CONDITIONS
Embryology
GIT starts development at 4wks
AOG
Derived from midgut & hindgut
Midgut – SMA Text
Hindgut – IMA
Distal anal canal – internal
pudendal
Dentate line – significance??
divides upper1/3 and lower3rd of anal canal
Anatomy
Large intestine
ileocecal valve to the anus
anatomical & functional divisions
Bowel wall
Colon
Rectum
Colon
Cecum, appendix
Ascending
Large
Transverse
Descending
Intestines
Sigmoid
Rectum
Anal canal
Pararectal
Fascia
Presacral fascia
Waldeyer’s fascia
Denonvilliers’ fascia
Lateral ligaments
Pelvic Floor (diaphragm)
pubococcygeus, iliococcygeus, and
puborectalis >> levator ani
supports the pelvic organs
regulates defecation
Arterial Supply
and Venous
Drainage
COLON
SMA, IMA
SMV, IMV
RECTUM
Upper and middle
superior rectal artery & vein
Lower
Internal iliac artery
Middle rectal veins
Lymphatic
Drainage
Follow the regional arteries
Epicolic
Paracolic
Intermediate
Main
Colon
Rectum
Colon
Nerve
Sympathetic (inhibitory)
Parasympathetic (stimulatory)
Supply
NORMAL
major site for water absorption and
PHYSIOLOGY electrolyte exchange
bacterial degradation of protein and
urea produces ammonia
Short-chain fatty acids – important
source of energy for the colonic mucosa
Microflora : anaerobes & aerobes
Intestinal gas : nitrogen, oxygen, carbon
dioxide, hydrogen, and methane
2 patterns:
Segmental
Motility
Propagated
Circadian rhythm
Food ingestion
Clinical evaluation
History – onset and duration of symptoms
Physical examination – DRE, abdominal evaluation
Clinical impression
Differentials: Benign vs Malignancy
Work-up: Diagnostic Imaging , Tumor markers
Common complaints
Constipation vs Obstruction
Diarrhea
Abdominal and Pelvic pain
GI bleeding – melena vs hematochezia
Peri-Anal symptoms:
Pain
Bleeding
Mass
Tenesmus
Work-up
Radiologic imaging
Plain Abdominal Xray and
Contrast studies
Abdominal ultrasound
Anal ultrasound
Abdominal CT scan
Pelvic MRI
PET-CT scan
Angiography
Imaging
Endorectal Ultrasound
Work-up
Endoscopy
Anoscopy
Proctosigmoidoscopy
Flexible sigmoidoscopy
Colonoscopy
Enteroscopy
Laparoscopy
Endoscopy
Laboratory Studies
FOBT and FIT
Stool studies
Tumor markers - CEA
Genetic Testing - FAP
Preparing a patient
for colorectal surgery
Pre-op, check for:
Operability – surgical
candidate
Resectability of the tumor
Nutritional status
Correctable fluid and
electrolyte, bleeding
problems
MALIGNANT
CURATIVE : Proximal
PRINCIPLES mesenteric vessel ligation &
Radical mesenteric clearance
OF
PALLIATIVE : Limited
RESECTIONS resections for incurable cancer
BENIGN
RIGHT COLECTOMY VS EXTENDED RIGHT COLECTOMY
TRANSVERSE
COLECTOMY
LEFT COLECTOMY VS EXTENDED LEFT COLECTOMY
SIGMOID
COLECTOMY
PRINCIPLES OF RESECTIONS
TOTAL COLECTOMY-
SUBTOTAL COLECTOMY – Preserved the superior rectal HARTMANN’S PROCEDURE
Resection + End colostomy + Pouch
EMERGENCY Patient may be unstable,
Unprepared
(Obstruction,Bleeding.Perforation)
PRINCIPLES Right-sided
Anastomoses
Resect +
OF Left sided
Resect + Anastomose (on table
RESECTIONS lavage)
Resect + Anastomose + Proximal
diversion
Resect + Ostomy
Subtotal colectomy
Ulcerative colitis
Inflammatory Crohn’s disease
Indeterminate colitis
Bowel Disease
Ulcerative
characterized by remissions and
exacerbations
onset : insidious or abrupt
Colitis
earliest manifestation : mucosal edema
extraintestinal manifestations of the disease
may be present
continuous involvement of rectum and colon
“backwash ileitis”
Sx : bloody diarrhea and crampy abdominal
pain
Fever – fulminant colitis / toxic megacolon
Dx: colonoscopy, biopsy
Indications for surgery
Emergency
Elective
Ulcerative Operative management:
Emergency
Colitis
total abdominal colectomy with end
ileostomy (with or without a mucus
fistula)
Decompression/diversion - too unstable
Elective
Total proctocolectomy with end
ileostomy
Crohn’s
exacerbations and remissions
may affect any portion of the intestinal
tract
Disease
Dx : colonoscopy, EGD, barium studies
Skip lesions, rectal sparing
MC site : ileum and cecum
Surgery reserved for complications
Acute : fistula +/- intraabdominal
abscess
Chronic : strictures
Diverticular Disease
Diverticula
abnormal outpouchings or sacs of
the colon wall
Pathophysiology
high intraluminal pressures
disordered motility
alterations in colonic structure
diets low in fiber
formed on the mesenteric side of
the antimesenteric taeniae coli
sigmoid & descending colon
Diverticulosis
diverticula without inflammation
thought to be an acquired disorder,
Diverticular
but the etiology is poorly understood
high fiber diet seems to decrease
incidence
Disease
Diverticulitis
inflammation and infection
associated with diverticula
Diverticulitis
refers to inflammation and infection
associated with a diverticulum
spectrum ranges from mild,
uncomplicated diverticulitis to free
perforation and diffuse peritonitis
present with left-sided abdominal pain,
with or without fever, and leukocytosis
Dx
Xray
CT scan
left lower quadrant pain and tenderness
CT findings : pericolic soft tissue
stranding, colonic wall thickening, and/
Uncomplicated or phlegmon
most will respond to outpatient therapy
Diverticulitis usually respond within 48 hours
?? colonoscopy, contrast enema
sigmoid colectomy with a primary
anastomosis
Abscess
Complicated Obstruction
Peritonitis (free perforation)
Diverticulitis Fistulas
Complicated
Diverticulitis
ABSCESS
*Hinchey Staging System
Pelvic abscess
OBSTRUCTION
occur in approximately 67% of
patients who develop acute
diverticulitis
Complicated incomplete obstruction often
respond to resuscitation and
Diverticulitis decompression
Relief of obstruction : Elective vs
emergency
Complicated
Diverticulitis
FISTULA
FISTULA
relatively common complication of
diverticulitis
dome of bladder, vagina, small
bowel
Recurrent UTI, pneumaturia,
fecaluria
Complicated
broad-spectrum antibiotics
Keypoints : Diverticulitis
define anatomy
exclude other diagnosis
Colonoscopy, CT scan
Complicated Diverticulitis
HEMORRHAGE
erosion of the peridiverticular arteriole
may be massive
80% stops spontaneously
For patients actively bleeding
RESUSCITATION
Localize bleeding
Bowel conservation
➢ For patients who have stopped bleeding
Watch for 24 hours then bowel prep the next day
for colonoscopy
If active bleeding seen at endoscopy: injection/
clipping/cautery
occur more often in younger
patients, and Asian descent
most are asymptomatic
Right-sided dx usually made intraop
Diverticula Surgery: Ileocecal resection
preferred
POLYPS AND
ADENOCARCINOMA
Adenoma-Carcinoma
sequence
Activation of oncogenes (K-ras)
Inactivation of tumor suppressor
genes (APC, DCC, p53)
TARGET of
SCREENING
• COLONOSCOPY
• Diagnostic & Therapeutic
• visualization of the entire colon
and terminal ileum
• Early detection
POLYPS
• Cannot be distinguished GROSSLY
• All polyps should be removed or investigated
POLYPS
Hyperplastic
Inflammatory
Hamartomatous
Neoplastic / Adenomatous
NOT ALL ARE PREMALIGNANT
Hyperplastic
polyps
• usually small (<5 mm)
• show histologic characteristics
of hyperplasia without any
dysplasia
• not considered premalignant
• >2cm – risk of malignant
degeneration
• Hyperplastic polyposis
• Familial Juvenile Polyposis
• Autosomal dominant
• Seen in child, adolescent, or young
Hamartomatous adult
• Patient may develop hundreds of
polyps (Juvenile polyps in the colon and rectum
Polyps) • Annual screening beginning ages 10
and 12 years
• Treatment depends on degree of
rectal involvement
Peutz - Jeghers
Syndrome (PJS)
• Polyposis of the small intestine, colon and
rectum
• NOT thought to be at significant risk for
malignant degeneration
• MELANIN SPOTS in the buccal mucosa and lips
• SCREENING: baseline colonoscopy and upper GI
endoscopy at age 20 years followed by annual
sigmoidoscopy
Cronkite-Canada syndrome
polyposis with alopecia, cutaneous pigmentation,
and atrophy of the fingernails
and toenails
Diarrhea, malabsorption, protein-losing
enteropathy
Most patients die despite maximal medical
therapy
surgery is reserved for complications
Cowden Syndrome
• Autosomal dominant
• Hamartomas of ALL three embryonal cell layers
• Facial trichilemmomas – small papules on
skin
• Breast cancer
• Thyroid disease
• GI polyps
• TREATMENT is based on symptoms
Inflammatory polyps
(Pseudopolyps)
• Occur in the context of IBD, amoebic
colitis, ischemic colitis and
schistosomal colitis
• NOT CONSIDERED PREMALIGNANT
• Polyposis may be extensive,
especially in patients with severe
colitis, and may mimic FAP
ADENOMATOUS
POLYPS
• 25% of the population older than
50 years
• dysplastic by definition
• risk of malignant degeneration is
related to size and type of polyp
• Tubular, villous, tubulovillous
Snare excision
Endoscopic •
• Saline lift technique
polypectomy • Endoscopic Submucosal Dissection
Endoscopic
polypectomy
Injection of methylene blue
“tattooing”
Complications
Perforation
Bleeding
Surgical options for Adenomatous
Polyps
TRANSANAL EXCISION COLECTOMY
Inherited • Familial Adenomatous Polyposis
(FAP)
Colorectal •
•
Attenuated FAP
HNPCC (Lynch Syndrome)
Cancer • Familial Colorectal Cancer
Familial Adenomatous Polyposis
(FAP)
➢ Rare: 1% of all colorectal
adenocarcinomas
➢ Autosomal dominant
➢ Genetic abnormality: mutation in the
APC gene
➢ Hundreds to thousands of adenomatous
polyps after puberty
➢ Lifetime risk of colorectal cancer: 100%
by age 50 years
Familial Adenomatous Polyposis (FAP)
➢ FAP patients are also at risk for the
development of adenomas
anywhere in the gastrointestinal tract,
particularly in the duodenum.
➢ Periampullary carcinoma is a particular
concern.
➢ Upper endoscopy is therefore
recommended for surveillance every 1 to 3
years beginning at age 25 to 30 years.
FAP TREATMENT
SURGERY!!! Three operative procedures
Total proctocolectomy with an end
(Brooke) ileostomy;
Total abdominal colectomy with
ileorectal anastomosis;
Restorative proctocolectomy with ileal
pouch–anal anastomosis with or without
a temporary ileostomy
HNPCC / LYNCH SYNDROME
More common than FAP, but is still extremely rare (1%–
3%)
The genetic defects associated with HNPCC arise from
errors in mismatch repair, the phenotypic result MSI.
Autosomal dominant pattern
Early age (average age, 40–45 years)
Approximately 70% of affected individuals will develop
colorectal cancer.
Better prognosis
HNPCC / LYNCH SYNDROME
High risk of endometrial carcinoma
Transvaginal ultrasound or endometrial aspiration biopsy recommended annually
after age 25 to 35 years.
Surgery:
Total colectomy with ileorectal anastomosis is recommended once adenomas or a
colon carcinoma is diagnosed.
Prophylactic hysterectomy and bilateral salpingo-oophorectomy should be
considered in women who have completed childbearing
FAMILIAL COLON ADENOCARCINOMA
Nonsyndromic familial colorectal cancer accounts for 10% to 15% of
patients with colorectal
cancer.
Risk : increases with a family history of the disease.
Screening colonoscopy is recommended every 5 years beginning at age 40
years or beginning 10 years before the age of the earliest diagnosed
patient.
COLON ADENOCARCINOMA
COLORECTAL CANCER STAGING
COLON CANCER TREATMENT
TREATMENT
OTHER NEOPLASMS
Carcinoid tumors : occur most commonly in the GIT ,25%
in the rectum. Most are benign, overall survival is greater
than 80%.
Treatment : Transanal excision vs Radical surgery
Lipomas : Benign lesion
Treatment : Resection by colonoscopic techniques or by
enucleation or limited colectomy.
Lymphoma : is rare but accounts for about 10%
Cecum is most often involved.
Treatment : Bowel resection
THANK YOU!!!
