Colorectal Student Copy PDF

COLON and RECTUM OUTLINE u ANATOMY AND PHYSIOLOGY u CLINICAL EVALUATION u GENERAL SURGICAL CONSIDERATIONS u INFLAMMATORY BOWEL DISEASE u DIVERTICULAR DISEASE u ADENOCARCINOMA AND POLYPS u INHERITED COLORECTAL CANCER u OTHER NEOPLASM AND BENIGN CONDITIONS Embryology u G...

COLON and RECTUM OUTLINE u ANATOMY AND PHYSIOLOGY u CLINICAL EVALUATION u GENERAL SURGICAL CONSIDERATIONS u INFLAMMATORY BOWEL DISEASE u DIVERTICULAR DISEASE u ADENOCARCINOMA AND POLYPS u INHERITED COLORECTAL CANCER u OTHER NEOPLASM AND BENIGN CONDITIONS Embryology u GIT starts development at 4wks AOG u Derived from midgut & hindgut u Midgut – SMA u Hindgut – IMA u Distal anal canal – internal pudendal u Dentate line – significance?? Anatomy u Large intestine u ileocecal valve to the anus u anatomical & functional divisions u Bowel wall u Colon u Rectum  u Colon u Cecum, appendix Ascending Large u u Transverse u Descending Intestines u Sigmoid u Rectum u Anal canal Pararectal Fascia u Presacral fascia u Waldeyer’s fascia u Denonvilliers’ fascia u Lateral ligaments Pelvic Floor (diaphragm) u pubococcygeus, iliococcygeus, and puborectalis >> levator ani u supports the pelvic organs u regulates defecation Arterial Supply and Venous Drainage u COLON u SMA, IMA u SMV, IMV u RECTUM u Upper and middle u superior rectal artery & vein u Lower u Internal iliac artery u Middle rectal veins Lymphatic Drainage u Follow the regional arteries u Epicolic u Paracolic u Intermediate u Main u Colon u Rectum Colon Nerve u Sympathetic (inhibitory) u Parasympathetic (stimulatory) Supply NORMAL major site for water absorption and PHYSIOLOGY u electrolyte exchange u bacterial degradation of protein and urea produces ammonia u Short-chain fatty acids – important source of energy for the colonic mucosa u Microflora : anaerobes & aerobes u Intestinal gas : nitrogen, oxygen, carbon dioxide, hydrogen, and methane  u 2 patterns: Segmental Motility u u Propagated u Circadian rhythm u Food ingestion Clinical evaluation u History – onset and duration of symptoms u Physical examination – DRE, abdominal evaluation u Clinical impression u Differentials: Benign vs Malignancy u Work-up: Diagnostic Imaging , Tumor markers Common complaints u Constipation vs Obstruction u Diarrhea u Abdominal and Pelvic pain u GI bleeding – melena vs hematochezia u Peri-Anal symptoms: u Pain u Bleeding u Mass u Tenesmus Work-up Radiologic imaging u Plain Abdominal Xray and Contrast studies u Abdominal ultrasound u Anal ultrasound u Abdominal CT scan u Pelvic MRI u PET-CT scan u Angiography Imaging Endorectal Ultrasound Work-up Endoscopy u Anoscopy u Proctosigmoidoscopy u Flexible sigmoidoscopy u Colonoscopy u Enteroscopy u Laparoscopy Endoscopy Laboratory Studies u FOBT and FIT u Stool studies u Tumor markers - CEA u Genetic Testing - FAP Preparing a patient for colorectal surgery u Pre-op, check for: u Operability – surgical candidate u Resectability of the tumor u Nutritional status u Correctable fluid and electrolyte, bleeding problems  u MALIGNANT u CURATIVE : Proximal PRINCIPLES mesenteric vessel ligation & Radical mesenteric clearance OF u PALLIATIVE : Limited RESECTIONS resections for incurable cancer u BENIGN RIGHT COLECTOMY VS EXTENDED RIGHT COLECTOMY TRANSVERSE COLECTOMY LEFT COLECTOMY VS EXTENDED LEFT COLECTOMY SIGMOID COLECTOMY PRINCIPLES OF RESECTIONS SUBTOTAL COLECTOMY – TOTAL COLECTOMY- HARTMANN’S PROCEDURE Preserved the sigmoidal Preserved the superior rectal Resection + End colostomy + Pouch  u EMERGENCY Patient may be unstable, Unprepared u (Obstruction, Bleeding, Perforation) PRINCIPLES u Right-sided Anastomoses Resect + OF u Left sided u Resect + Anastomose (on table RESECTIONS lavage) u Resect + Anastomose + Proximal diversion u Resect + Ostomy u Subtotal colectomy  u Ulcerative colitis Inflammatory u Crohn’s disease Bowel Disease u Indeterminate colitis Ulcerative u remissions and exacerbations u insidious or abrupt mucosal edema Colitis u u extraintestinal manifestations u continuous involvement of rectum and colon u “backwash ileitis” u Sx : bloody diarrhea and crampy abdominal pain u Fever – fulminant colitis / toxic megacolon u Dx: colonoscopy, biopsy  u Indications for surgery u Emergency u Elective Ulcerative u Operative management: u Emergency u total abdominal colectomy with Colitis end ileostomy (with or without a mucus fistula) u Decompression/diversion - too unstable u Elective u Total proctocolectomy with end ileostomy Crohn’s u u exacerbations and remissions may affect any portion of the intestinal tract Disease u u Dx : colonoscopy, EGD, barium studies Skip lesions, rectal sparing u MC site ?? u Surgery reserved for complications u Acute : u Chronic :  Diverticular Disease u Diverticula u abnormal outpouchings or sacs of the colon wall uhigh intraluminal pressures udisordered motility ualterations in colonic structure udiets low in fiber  u Diverticulosis u diverticula without inflammation u thought to be an acquired disorder, but the etiology is poorly Diverticular u understood high fiber diet seems to decrease Disease incidence u Diverticulitis u inflammation and infection associated with diverticula Diverticulitis u inflammation and infection associated with a diverticulum u mild, uncomplicated diverticulitis to free perforation and diffuse peritonitis u present with left-sided abdominal pain, with or without fever, and leukocytosis u Dx u Xray u CT scan  u left lower quadrant pain and tenderness Uncomplicated u u CT findings : ?? most will respond to outpatient Diverticulitis u therapy usually respond within 48 hours u ?? colonoscopy, contrast enema u sigmoid colectomy with a primary anastomosis Complicated u Abscess u Obstruction Diverticulitis u u Peritonitis (free perforation) Fistulas Complicated Diverticulitis u ABSCESS u Hinchey Staging System Pelvic abscess  u OBSTRUCTION u occur in approximately 67% of patients who develop acute Complicated diverticulitis u incomplete obstruction often respond to resuscitation and Diverticulitis decompression u Relief of obstruction : Elective vs emergency Complicated Diverticulitis FISTULA u FISTULA u relatively common complication u dome of bladder, vagina, small bowel u Recurrent UTI, pneumaturia, fecaluria Complicated Diverticulitis u broad-spectrum antibiotics u Keypoints : u define anatomy u exclude other diagnosis u Colonoscopy, CT scan Complicated Diverticulitis u HEMORRHAGE uerosion of the peridiverticular arteriole umay be massive u80% stops spontaneously  u occur more often in younger patients, and Asian descent u most are asymptomatic Right-sided u dx usually made intraop Diverticula u Surgery: Ileocecal resection preferred POLYPS AND ADENOCARCINOMA Adenoma-Carcinoma sequence u Activation of oncogenes (K-ras) u 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 u Hyperplastic u Inflammatory u Hamartomatous u Neoplastic / Adenomatous u NOT ALL ARE PREMALIGNANT Hyperplastic polyps usually small (