Colorectal Surgery

01 Colorectal Anatomy Essentials

Colorectal surgery encompasses the colon, rectum, anus, and pelvic floor, along with the small bowel when it overlaps with colorectal pathology. A scribe cannot chart effectively without a solid mental map of the large bowel, its vascular supply, and the anatomy of the anorectum. Every operative note, pathology report, and endoscopy document will reference these structures by exact anatomical name.

The Colon — Segments & Landmarks

The large intestine begins at the ileocecal valve and terminates at the anal verge. Moving distally, the segments are: cecum (with the appendix), ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon, and rectum. The rectum is approximately 12–15 cm long and is divided into upper, mid, and lower thirds. Below the rectum lies the anal canal (~4 cm), bounded superiorly by the dentate (pectinate) line — the critical anatomic and embryologic boundary between columnar rectal mucosa (visceral, insensate) and squamous anoderm (somatic, exquisitely sensitive).

Vascular Supply — Why Resections Are Named the Way They Are

The colon has a split blood supply that dictates every colectomy boundary. The superior mesenteric artery (SMA) supplies the right colon via the ileocolic, right colic, and middle colic branches — up to roughly the splenic flexure. The inferior mesenteric artery (IMA) supplies the left colon and rectum via the left colic, sigmoidal branches, and superior rectal artery. The rectum additionally receives middle rectal arteries (from the internal iliac) and inferior rectal arteries (from the internal pudendal). The marginal artery of Drummond runs along the mesenteric border and provides collateral flow between SMA and IMA territories. The watershed zones at the splenic flexure (Griffiths' point) and rectosigmoid junction (Sudeck's point) are vulnerable to ischemic colitis.

The Rectum, Mesorectum & Total Mesorectal Excision Plane

The rectum is surrounded by the mesorectum, a fatty envelope containing lymphatic drainage enclosed by the mesorectal fascia. Quality rectal cancer surgery requires total mesorectal excision (TME) — sharp dissection in the "holy plane" between mesorectal fascia and presacral (Waldeyer's) fascia. Key surrounding structures the surgeon will name in every rectal case: the presacral venous plexus, hypogastric nerves (sympathetic), nervi erigentes (parasympathetic, S2–S4), the peritoneal reflection (anterior), and for males the Denonvilliers' fascia separating the rectum from the prostate/seminal vesicles.

Anal Canal & Sphincter Complex

The anal sphincter has two components: the internal anal sphincter (IAS) — smooth muscle, involuntary, continuous with the rectal circular muscle — and the external anal sphincter (EAS) — skeletal muscle, voluntary, innervated by the inferior rectal branch of the pudendal nerve. Between them lies the intersphincteric plane. The puborectalis sling of the levator ani maintains the anorectal angle and is essential for continence. The anal columns of Morgagni terminate at the dentate line in anal crypts that drain the anal glands — the origin of cryptoglandular abscesses and fistulas.

02 Scribe Documentation Framework

Colorectal notes are structured around a few recurring encounter types: new consult for a colonoscopy finding (polyp, mass, bleeding), inflammatory bowel disease follow-up, diverticulitis presentation (clinic or ED), anorectal complaint, pre-op and post-op cancer clinic, and stoma clinic. Each has its own rhythm.

03 Colorectal Cancer Neoplastic

Colorectal cancer (CRC) is the third most common cancer in both sexes in the United States and the second leading cause of cancer death overall. It is the defining diagnosis of colorectal surgery clinic. CRC arises almost exclusively from the adenoma–carcinoma sequence or the serrated pathway, and is the reason screening colonoscopy exists.

Pathophysiology & Location-Based Biology

Right-sided (cecum, ascending, proximal transverse) tumors tend to be larger, fungating, and present with iron-deficiency anemia and occult blood loss rather than obstruction — the bowel lumen is wider and stool more liquid. They are more often microsatellite-instability-high (MSI-H) and are linked to Lynch syndrome and the serrated pathway. Left-sided tumors (splenic flexure, descending, sigmoid) are more often annular "apple-core" lesions producing change in stool caliber, constipation, hematochezia, and large bowel obstruction. Rectal cancers present with hematochezia, tenesmus, urgency, and change in bowel habits and are staged and managed distinctly from colon cancer because of pelvic anatomy and the value of neoadjuvant therapy.

Presentation & Red Flags

Workup

Every new CRC patient gets: full colonoscopy with biopsy (to confirm histology and screen for synchronous lesions — 2–5% incidence), CT chest/abdomen/pelvis with contrast for staging, CEA (carcinoembryonic antigen, baseline tumor marker), and a CBC, CMP, LFTs. For rectal cancer, additionally: pelvic MRI with rectal protocol to define T stage, mesorectal fascia involvement, and extramural vascular invasion, and endorectal ultrasound (ERUS) for early T stage assessment. Molecular testing includes MMR/MSI (mismatch repair, universal per NCCN), KRAS/NRAS/BRAF, and HER2 for metastatic disease.

AJCC 8th Edition TNM Staging

Management Overview

Colon cancer management is primarily surgical for stages I–III, with adjuvant chemotherapy (FOLFOX or CAPOX) added for stage III and high-risk stage II disease, per the NCCN Colon Cancer Guidelines. Resection is tailored to the tumor location: right hemicolectomy for cecum through proximal transverse, extended right for distal transverse/splenic flexure, left hemicolectomy for descending, sigmoidectomy for sigmoid. Oncologic principles include high vascular ligation, adequate proximal/distal margins (5 cm typical), and harvest of at least 12 lymph nodes.

Rectal cancer management is more complex. Locally advanced rectal cancer (T3/T4 or node positive) is increasingly managed with total neoadjuvant therapy (TNT) — full-course chemotherapy plus chemoradiation before surgery — which improves pathologic complete response rates and enables watch-and-wait strategies in select patients (NCCN Rectal Cancer Guidelines). Surgical options include low anterior resection (LAR) for tumors that allow a sphincter-sparing anastomosis, and abdominoperineal resection (APR) with permanent colostomy for very low tumors that cannot obtain a negative distal margin. Transanal excision or TAMIS/TEM may be appropriate for carefully selected early T1 tumors.

Screening

USPSTF 2021 CRC screening recommends beginning average-risk screening at age 45 (lowered from 50) and continuing to age 75. Acceptable modalities include colonoscopy every 10 years, stool-based testing (FIT annual, FIT-DNA every 3 years), or flexible sigmoidoscopy. The ACG guideline explicitly endorses 45 as the start age. High-risk patients (family history, polyposis, IBD) start earlier and screen more frequently.

04 Polyps & Hereditary Polyposis Syndromes Neoplastic

Most colorectal cancers begin as polyps, so polyp management and surveillance are central to colorectal practice. Polyps are classified histologically and by morphology (Paris classification: pedunculated, sessile, flat, depressed).

Polyp Histology

Hereditary Polyposis Syndromes

05 Inflammatory Bowel Disease (Surgical) Inflammatory

Ulcerative colitis (UC) and Crohn disease are the two major inflammatory bowel diseases. Colorectal surgeons see them when medical therapy fails, when dysplasia or cancer is found, or when complications develop (stricture, fistula, perforation, toxic megacolon).

Ulcerative Colitis

UC is a continuous mucosal inflammation that starts at the rectum and extends proximally. It never skips, never reaches beyond the colon (ileal "backwash" aside), and is limited to the mucosa/submucosa. Extent is classified as proctitis, left-sided colitis (to splenic flexure), or extensive/pancolitis. Symptoms: bloody diarrhea, tenesmus, urgency, lower abdominal cramping, nocturnal bowel movements. Extraintestinal: primary sclerosing cholangitis (PSC), uveitis, erythema nodosum, pyoderma gangrenosum, arthritis. Surgical indications: medically refractory disease, dysplasia or cancer on surveillance, toxic megacolon, massive hemorrhage. The definitive operation is total proctocolectomy with ileal pouch-anal anastomosis (IPAA, J-pouch), typically in 2 or 3 stages. See the ASCRS UC Clinical Practice Guideline.

Crohn Disease

Crohn is a transmural, patchy, skip-lesion inflammation that can affect any site from mouth to anus. Ileocolic involvement is most common. The three behavioral phenotypes (Montreal classification) are inflammatory (B1), stricturing (B2), and penetrating/fistulizing (B3). Symptoms depend on location: RLQ pain and diarrhea with ileocolic disease, perianal fistulas and abscesses with colonic/perianal disease, obstructive symptoms with stricturing phenotype. Surgery is not curative — disease recurs, typically at the anastomosis — so the principle is bowel preservation: resect as little as possible, use strictureplasty for short strictures, and reserve resection for failure. Common operations: ileocolic resection for terminal ileal disease, strictureplasty, diverting loop ileostomy for severe perianal Crohn. See the ASCRS Crohn Disease Guideline.

06 Diverticular Disease Inflammatory

Diverticula are mucosal outpouchings through the colonic wall at points of weakness where the vasa recta penetrate. They are overwhelmingly sigmoid in Western populations (high-pressure segment, narrow caliber, low-fiber diets). Diverticulosis is the presence of diverticula; diverticulitis is inflammation/infection, typically from micro-perforation of a diverticulum. Diverticular bleeding is painless hematochezia from erosion of the vasa recta at the neck of a diverticulum.

Uncomplicated vs Complicated Diverticulitis

Uncomplicated diverticulitis = localized inflammation without abscess, perforation, fistula, obstruction, or stricture. Complicated diverticulitis = any of the above. The historical teaching that all diverticulitis requires antibiotics has evolved; mild uncomplicated diverticulitis in selected patients can be managed without antibiotics per the ASCRS Diverticulitis Guideline.

Hinchey Classification of Perforated Diverticulitis

Recurrent Diverticulitis & Elective Resection

The old rule of "resect after two attacks" has been abandoned. Current guidance individualizes the decision based on severity, symptoms between episodes, immunocompromise, fistula, stricture, and patient preference. Complicated diverticulitis (perforation, abscess requiring drainage, fistula, obstruction) and chronic smoldering symptoms are relative indications for elective sigmoidectomy. Fistulas complicating diverticulitis include colovesical (most common, presents with pneumaturia/fecaluria/UTI), colovaginal, coloenteric, and colocutaneous.

07 Volvulus & Large Bowel Obstruction Mechanical

Volvulus is rotation of a bowel loop around its mesenteric axis, producing obstruction and potentially ischemia. Sigmoid volvulus (most common, 60–75%) affects elderly, debilitated, institutionalized patients with chronic constipation. Classic imaging: "coffee bean" sign on plain film, "bird's beak" on contrast enema, whirl sign on CT. First-line management is endoscopic detorsion (flexible sigmoidoscopy with decompression tube), followed by elective sigmoidectomy during the same admission because recurrence without resection is ~50%. Emergent sigmoidectomy (Hartmann) is required if there is peritonitis, suspected ischemia, or failure of endoscopic detorsion.

Cecal volvulus (~25%) occurs in younger patients with congenitally mobile cecum. Imaging: "comma" or displaced cecum in LUQ. Endoscopic detorsion is generally unsuccessful; treatment is right hemicolectomy (or cecopexy in very high-risk patients). Cecal bascule is anterior folding of the cecum without axial rotation.

Large Bowel Obstruction (LBO)

Causes: cancer (most common in adults), diverticular stricture, volvulus, Ogilvie syndrome (acute colonic pseudo-obstruction, non-mechanical). LBO with a competent ileocecal valve produces a closed-loop obstruction — the cecum dilates progressively and may perforate at > 12 cm diameter (Laplace's law). Workup: CT with contrast to identify transition point. Management depends on cause: emergent decompression (stent or resection) for obstructing cancer, Hartmann or primary resection for malignant LBO. Ogilvie syndrome is treated with IV neostigmine after mechanical obstruction is excluded.

08 Small Bowel Obstruction & Ileus Mechanical

Though technically general surgery territory, colorectal surgeons manage SBO in their post-op patients constantly. Causes of SBO in a colorectal patient: adhesions (far and away most common after any abdominal surgery), internal hernia, parastomal hernia, incisional hernia, anastomotic stricture, recurrent cancer, Crohn stricture, gallstone ileus, intussusception.

Presentation: crampy abdominal pain, distension, nausea/vomiting (feculent with distal obstruction), obstipation. CT findings: dilated small bowel loops (> 3 cm), transition point, collapsed distal bowel, pneumatosis or portal venous gas (ischemia). Management of uncomplicated partial SBO: NPO, NG decompression, IV fluids, serial exams. Water-soluble contrast challenge (Gastrografin) has both diagnostic and therapeutic value. Surgery is indicated for complete obstruction, closed-loop, ischemia, failure to resolve in 3–5 days, or peritonitis.

Post-op ileus is functional (non-mechanical) dysmotility after abdominal surgery. Expected up to 3–5 days. Prolonged ileus is defined as > 5 days. Management: NG decompression if vomiting, correct electrolytes (especially potassium and magnesium), limit opioids, ambulate. ERAS protocols reduce ileus duration significantly.

09 Hemorrhoidal Disease Anorectal

Hemorrhoids are normal vascular cushions in the submucosa of the anal canal; they become symptomatic when engorged, prolapsed, or thrombosed. Internal hemorrhoids arise above the dentate line, are covered by columnar mucosa, and are insensate — they bleed painlessly. External hemorrhoids arise below the dentate line, are covered by anoderm, and are exquisitely sensitive — they hurt when thrombosed. Classic positions: right anterior, right posterior, left lateral (3, 7, 11 o'clock in prone jackknife).

Goligher Grading of Internal Hemorrhoids

Management follows a stepwise escalation per the ASCRS Hemorrhoid Guideline. First-line is medical: fiber (25–35 g/day), increased water, sitz baths, topical hydrocortisone or lidocaine, avoidance of prolonged toilet sitting. Office procedures (band ligation, sclerotherapy, IRC) are highly effective for grades I–II. Grade III–IV and mixed internal-external disease usually need operative hemorrhoidectomy.

Thrombosed external hemorrhoid is an acute painful purple perianal lump from clotted external hemorrhoid. If within 48–72 hours of onset, excision under local anesthesia provides rapid relief. After 72 hours the pain is typically receding and conservative management suffices.

10 Anal Fissure Anorectal

An anal fissure is a linear tear in the anoderm distal to the dentate line. Posterior midline (90%) is classic; anterior midline is more common in women post-delivery. Fissures off the midline should raise suspicion for Crohn, HIV, tuberculosis, syphilis, or malignancy. Presentation: sharp pain with defecation ("passing glass"), small amount of bright red blood on paper, anal spasm, sometimes a sentinel tag. Pathophysiology: hypertonic internal anal sphincter produces ischemia of the posterior commissure, preventing healing.

Management per the ASCRS Anal Fissure Guideline: first-line is fiber/water/sitz baths plus topical chemical sphincterotomy — topical nitroglycerin 0.4% ointment BID or topical nifedipine/diltiazem — which relaxes the IAS and restores blood flow. Botulinum toxin injection is a second-line option. Lateral internal sphincterotomy (LIS) is the surgical gold standard for chronic refractory fissures; incontinence risk must be discussed, particularly in women with prior obstetric injury.

11 Perianal Abscess & Anal Fistula Anorectal

The cryptoglandular theory: infection of an anal gland at the dentate line spreads through the intersphincteric plane to form an abscess, and when the abscess drains (spontaneously or surgically), a chronic epithelialized tract can remain as a fistula-in-ano.

Abscess Classification by Location

Perianal (most common, superficial): drains at the anal verge. Ischiorectal: lateral, may be bilateral (horseshoe). Intersphincteric: between IAS and EAS, painful but no external swelling. Supralevator: above the levators, deep, may be from pelvic source. Management: incision and drainage, generally with a cruciate incision as close to the anal verge as possible to minimize future fistula tract length. Antibiotics alone are inadequate; drainage is required.

Park's Classification of Anal Fistulas

Goodsall's rule predicts the internal opening: external openings anterior to a transverse line through the anus tract radially to the nearest anal crypt; posterior openings curve to the posterior midline.

Fistula Management

Treatment depends on tract depth and sphincter involvement per the ASCRS Anorectal Abscess/Fistula Guideline. Simple low fistulas (minimal sphincter involvement) can be treated with fistulotomy. Complex fistulas (high transsphincteric, anterior in women, Crohn, multiple tracts, recurrent) require sphincter-preserving options: draining seton (silastic loop to maintain drainage), cutting seton, LIFT (ligation of intersphincteric fistula tract), endorectal advancement flap, fibrin glue, or fistula plug. Rectovaginal fistulas are particularly challenging; options include advancement flap, bioprosthetic interposition, or diverting stoma for Crohn-related disease.

12 Pilonidal Disease Anorectal

Pilonidal disease is a chronic inflammatory condition of the natal cleft, caused by hair penetration and foreign-body reaction. Common in young males with thick body hair, obesity, prolonged sitting. Presents as an acute midline abscess or chronic draining sinus with lateral openings. Treatment: acute abscess requires off-midline I&D. Chronic disease is treated with pit-picking (Bascom), excision with primary closure, excision with healing by secondary intention, or flap procedures (Karydakis, Limberg rhomboid, cleft lift) for recurrent disease. See the ASCRS Pilonidal Guideline.

13 Anal Cancer & HPV-Related Disease Neoplastic

Anal cancer is overwhelmingly squamous cell carcinoma (SCC) of the anal canal, strongly linked to HPV (types 16, 18), HIV, immunosuppression, receptive anal intercourse, and smoking. Adenocarcinoma of the anal canal is rare and usually arises from anal glands or ducts; it behaves like rectal cancer.

Presentation: rectal bleeding, anal pain, palpable mass, pruritus, tenesmus, inguinal lymphadenopathy. Exam under anesthesia with biopsy confirms diagnosis. Staging: MRI pelvis, CT chest/abdomen, PET/CT, HIV testing.

Treatment is non-surgical: the Nigro protocol — concurrent chemoradiation with 5-FU + mitomycin C — is curative for most SCC of the anal canal. Surgery (APR) is reserved for persistent/recurrent disease (salvage) per the NCCN Anal Cancer Guidelines. Surveillance is clinical (DRE, anoscopy, inguinal palpation) with imaging for recurrence.

Anal intraepithelial neoplasia (AIN) is the precursor lesion (low-grade LSIL, high-grade HSIL). High-resolution anoscopy (HRA) with targeted ablation is used for surveillance, particularly in HIV+ men who have sex with men. Condyloma acuminatum (anogenital warts) is treated with topical agents (imiquimod, podophyllin, TCA), excision, or electrocautery. Buschke-Löwenstein tumor is a giant condyloma / verrucous carcinoma variant that behaves locally aggressively and requires wide excision.

Pruritus ani is chronic perianal itching. Primary (idiopathic) forms are most common; secondary causes include fecal soilage, hemorrhoids, fissure, dietary triggers (coffee, spicy food, chocolate, citrus), fungal infection, psoriasis, lichen sclerosus, and rarely neoplasia. Management: eliminate irritants, gentle cleansing (avoid scrubbing and perfumed wipes), dry the perianal skin, mild topical hydrocortisone for short courses, and a dietary trial. Biopsy any suspicious lesion.

14 Rectal Prolapse, Rectocele & Pelvic Floor Pelvic Floor

Full-thickness rectal prolapse (procidentia) is protrusion of all layers of the rectal wall through the anus. Classic in elderly multiparous women. Symptoms: visible prolapse with Valsalva, mucus, bleeding, incontinence, constipation. Differentiate from mucosal prolapse (only mucosa) and internal intussusception (not visible externally; diagnosed on defecography).

Surgical approaches per the ASCRS Rectal Prolapse Guideline:

• Abdominal (preferred for good surgical candidates): ventral rectopexy (laparoscopic or robotic), suture rectopexy, resection rectopexy (Frykman-Goldberg).
• Perineal (for frail/elderly): Altemeier perineal proctosigmoidectomy, Delorme mucosal sleeve resection.

Rectocele is herniation of the anterior rectal wall into the vagina, presenting with obstructed defecation and need for vaginal splinting. Enterocele is small bowel herniation into the rectovaginal septum. Sigmoidocele is redundant sigmoid in the pelvis. Workup includes defecography and anorectal manometry. Management is first conservative (fiber, biofeedback) and escalates to transvaginal or transanal repair.

Anismus (paradoxical puborectalis contraction) is a pelvic floor dyssynergia where the puborectalis fails to relax with straining. Diagnosed on defecography and manometry. Treatment is biofeedback.

Solitary rectal ulcer syndrome (SRUS) is associated with chronic straining and internal intussusception. Presents with bleeding, mucus, tenesmus, and characteristic anterior rectal ulceration. Treatment focuses on the underlying defecation disorder (biofeedback, fiber); surgery is reserved for refractory cases.

Retrorectal (presacral) masses are uncommon lesions occupying the space between the rectum and sacrum. The broad differential includes congenital (tailgut cyst, epidermoid cyst, teratoma, anterior meningocele), neurogenic (schwannoma, neurofibroma), osseous (chordoma, sacral tumors), and inflammatory lesions. MRI pelvis is the imaging of choice. Most benign lesions require excision to rule out malignancy and prevent complications.

15 Fecal Incontinence & Constipation Functional

Fecal incontinence is involuntary passage of gas, liquid, or solid stool. Causes: obstetric sphincter injury (most common in women), prior anorectal surgery, neurologic disease, diabetes, diarrhea, rectal prolapse, radiation. Workup includes anorectal manometry, endoanal ultrasound (sphincter integrity), pudendal nerve terminal motor latency, defecography. Severity is quantified with the Wexner (Cleveland Clinic) Incontinence Score (0 = continent, 20 = complete incontinence, scoring frequency of incontinence to gas/liquid/solid, pad use, lifestyle alteration).

Management ladder: dietary modification and bulking agents, loperamide, biofeedback, sacral nerve stimulation (SNS) (first-line for refractory incontinence), injectable anal bulking agents, sphincteroplasty (overlapping), and diverting colostomy for severe refractory disease.

Chronic constipation evaluated by a colorectal surgeon is typically either slow-transit constipation or obstructed defecation. Workup: colonoscopy (rule out mass/stricture), colonic transit study (Sitz marker), anorectal manometry, defecography. The Wexner Constipation Score quantifies severity. Slow-transit refractory to medical therapy may be treated with total abdominal colectomy with ileorectal anastomosis; outcomes are variable and patient selection critical.

16 Ischemic & Infectious Colitis Inflammatory

Ischemic colitis most commonly affects watershed zones (splenic flexure, rectosigmoid). Non-occlusive in elderly with atherosclerosis, hypotension, cardiac surgery, vasopressors, cocaine, hypercoagulable states. Presents with sudden cramping lower abdominal pain, bloody diarrhea. CT shows segmental wall thickening. Colonoscopy shows patchy erythema, hemorrhagic mucosa, single-stripe sign. Most cases resolve with bowel rest, IV fluids, and antibiotics; gangrenous or full-thickness ischemia requires resection.

Pseudomembranous (C. difficile) colitis — the surgical urgency is fulminant C. difficile with megacolon, shock, lactic acidosis, or perforation. Surgical management is total abdominal colectomy with end ileostomy, or the diverting loop ileostomy with antegrade vancomycin lavage (Neal procedure) as a colon-sparing alternative. Medical management is PO vancomycin and IV metronidazole; fidaxomicin is increasingly first-line for recurrent disease.

Stercoral colitis/perforation is pressure necrosis from an impacted fecal bolus, classically at the antimesenteric border of the rectosigmoid. Elderly, constipated, bedbound patients. Emergent resection is required.

17 Ostomy Management & Complications Post-Op

Stomas are a central feature of colorectal surgery. A scribe must be able to describe a stoma accurately on exam.

Stoma Types

Stoma Siting & Care

Ideal stoma siting is performed pre-operatively by an ostomy nurse: within the rectus muscle, away from scars, skin folds, the beltline, and bony prominences, visible to the patient seated and standing. Poor siting is the single biggest driver of peristomal skin complications and appliance failure. A well-sited Brooke ileostomy should protrude 2–3 cm above the skin to allow effluent to drop cleanly into the bag. Colostomies can be flush or slightly raised.

Routine stoma care includes appliance changes every 3–5 days, skin barrier products for denuded peristomal skin, convexity appliances for retracted or flush stomas, and stoma paste or rings to seal irregular contours. Patients should be counseled to recognize warning signs: dusky color, bleeding beyond minor irritation, significant output changes, parastomal pain, or inability to pass flatus or stool.

Ostomy Complications

High-output ileostomy is a common post-op ED visit. Management: loperamide 4 mg QID, diphenoxylate/atropine, oral rehydration solutions, limit hypotonic fluids (water) which worsen sodium losses, codeine or tincture of opium for severe cases, PPI to reduce gastric secretions. Hospitalize for AKI or severe electrolyte derangement.

18 Anastomotic Leak & Post-Op Complications Post-Op

Anastomotic leak is the most feared complication of colorectal surgery. Incidence: 3–6% for colonic anastomosis, up to 15% for low pelvic (LAR) anastomosis. Risk factors: male sex, low anastomosis, neoadjuvant radiation, smoking, malnutrition, steroids, poor perfusion, tension. Classic presentation: post-op day 5–7 fever, tachycardia, leukocytosis, peritonitis, ileus, feculent drain output, or pelvic sepsis.

Workup: CT with rectal contrast (for low anastomoses) or oral/IV contrast. Management depends on severity: small contained leak → antibiotics + percutaneous drainage; large or uncontained leak → reoperation with takedown and diversion (Hartmann for left-sided, ileostomy + washout for protected anastomoses). ICG fluorescence angiography intraoperatively has been shown to reduce leak rates by confirming anastomotic perfusion.

Clavien-Dindo Classification of Surgical Complications

Other post-op complications to document: surgical site infection (superficial, deep, organ-space), ileus, SBO, urinary retention (especially after pelvic dissection from autonomic nerve injury), sexual dysfunction (anterograde ejaculation loss, erectile dysfunction), anastomotic stricture, incisional hernia, deep venous thrombosis/pulmonary embolism.

Low Anterior Resection Syndrome (LARS)

After sphincter-preserving rectal surgery, a significant proportion of patients develop LARS — a constellation of urgency, frequency, clustering, fragmentation, and incontinence related to loss of rectal reservoir function. Severity is graded by the LARS Score (0–42; 0–20 no LARS, 21–29 minor, 30–42 major). Management is multimodal: bulking agents, loperamide, biofeedback, pelvic floor physical therapy, sacral nerve stimulation, and dietary counseling. Always ask about and chart LARS symptoms on every post-LAR follow-up.

Pouchitis

Inflammation of the ileal pouch after IPAA occurs in up to 50% of UC patients over their lifetime. Presentation: increased stool frequency, urgency, cramping, bleeding, fever. Diagnosis by pouchoscopy with biopsy. First-line treatment is a two-week course of ciprofloxacin or metronidazole; chronic pouchitis may require budesonide, vedolizumab, or ustekinumab.

19 Colorectal Procedures — A to Z Operative

A colorectal scribe must recognize every procedure name. Operations can be performed open, laparoscopic, or robotic; robotic is increasingly favored for rectal cancer due to superior pelvic visualization. ICG fluorescence is used for perfusion assessment and sentinel node mapping.

Colonic Resections

Rectal Operations

Anorectal Procedures

ERAS — Enhanced Recovery After Surgery

ERAS protocols have transformed colorectal recovery. Key elements per the ERAS Society Colorectal Guideline:

• Pre-op: patient education, no prolonged fasting (clear liquids up to 2 h pre-op), carbohydrate loading, mechanical bowel prep + oral antibiotics for colorectal resections
• Intra-op: multimodal analgesia (avoid opioids), regional anesthesia (TAP block, epidural), goal-directed fluids, normothermia, minimally invasive approach
• Post-op: early PO intake, early ambulation (POD 0), early Foley removal, multimodal pain control (acetaminophen, NSAIDs, gabapentin), alvimopan for accelerated ROBF, DVT prophylaxis, early drain removal

20 Imaging, Endoscopy & Labs Diagnostics

Endoscopy

Colonoscopy is the workhorse — diagnostic and therapeutic. Quality metrics: adequate prep (Boston Bowel Prep Scale ≥ 6, no segment < 2), cecal intubation rate > 95%, adenoma detection rate > 25% in screening. Document findings by location (cm from anal verge or anatomic segment), size, morphology (Paris classification), and histology. Flexible sigmoidoscopy reaches the splenic flexure and is useful for distal lesions, rectal cancer follow-up, and volvulus detortion. Anoscopy and rigid sigmoidoscopy are office procedures for anorectal complaints.

Imaging

Labs

CEA baseline and surveillance in CRC (rising CEA suggests recurrence). CBC for anemia (right colon cancer), infection. CMP for electrolytes (high-output stoma), renal function, LFTs (metastasis). Lactate for suspected ischemia. Fecal calprotectin for IBD activity. C. difficile toxin/PCR for diarrhea. Stool studies for infectious etiologies. Type and screen/cross for major operations.

Surveillance After Curative CRC Resection

Per NCCN: history/physical + CEA every 3–6 months for 2 years then every 6 months to year 5; CT chest/abdomen/pelvis annually for 5 years (more frequent for high-risk disease); surveillance colonoscopy at 1 year post-op (or 3–6 months if not cleared pre-op), then 3 years, then every 5 years. Rising CEA prompts CT and, if negative, PET/CT.

Pathology Reports — What to Chart

Every colorectal pathology report contains specific elements the scribe should capture: tumor location and size, histologic type and grade, depth of invasion (T stage), lymphovascular invasion (LVI), perineural invasion (PNI), tumor budding, margin status (proximal, distal, radial/circumferential for rectum), number of lymph nodes examined and positive, MMR/MSI status, KRAS/NRAS/BRAF, and final pathologic TNM stage (pTNM; ypTNM if after neoadjuvant therapy). A circumferential margin < 1 mm is considered positive for rectal cancer and carries significant local recurrence risk.

21 Medications You Must Know Pharmacology

Bowel Preparation

Perioperative Antibiotics

Pre-op IV: cefoxitin, cefotetan, or ertapenem; alternative ampicillin-sulbactam or ciprofloxacin + metronidazole for beta-lactam allergy. Within 60 minutes of incision.

Post-op Pain & ERAS Adjuncts

Multimodal: scheduled acetaminophen, ketorolac/ibuprofen, gabapentin, IV/oral opioids for breakthrough, TAP block or epidural. Alvimopan (Entereg) is a peripheral mu-opioid antagonist used to accelerate GI recovery after bowel resection.

VTE Prophylaxis

Enoxaparin 40 mg SC daily (or BID in obese/high-risk), or unfractionated heparin 5000 U SC TID. Mechanical prophylaxis (SCDs) in all. Extended 28-day VTE prophylaxis for cancer surgery.

IBD Medications (Overview for Surgical Context)

Anorectal Topicals

Nitroglycerin 0.4% ointment (Rectiv) — anal fissure. Nifedipine 0.2–0.3% cream, diltiazem 2% gel — anal fissure alternatives with fewer headaches. Lidocaine 2–5% for symptomatic relief. Hydrocortisone (Anusol-HC, Proctofoam-HC) for hemorrhoids and pruritus ani. Sitz baths (warm water 10–15 minutes TID) are the cornerstone of anorectal comfort.

Bowel Regimen Medications

Fiber (psyllium, methylcellulose), docusate, polyethylene glycol (MiraLAX), bisacodyl, senna, lactulose, lubiprostone, linaclotide. Antidiarrheals: loperamide, diphenoxylate/atropine, codeine, tincture of opium. Antispasmodics: dicyclomine, hyoscyamine.

Chemotherapy Regimens (Know the Names)

Targeted agents: bevacizumab (anti-VEGF), cetuximab/panitumumab (anti-EGFR, for RAS wild-type left-sided disease), pembrolizumab (anti-PD-1, for MSI-H/dMMR tumors), encorafenib + cetuximab (BRAF V600E mutant), trastuzumab + pertuzumab/tucatinib (HER2 amplified).

22 Classification Systems Reference

Hinchey (Section 06), Goligher (Section 09), Park's (Section 11), AJCC TNM (Section 03), and Clavien-Dindo (Section 18) are fully enumerated in their respective sections.

23 Physical Exam — Anorectal & Abdominal Exam

Positioning: left lateral decubitus (Sims) or prone jackknife (best for anoscopy and office procedures). Always announce the exam in the note: "Anorectal exam performed in the prone jackknife position." Stoma exam detail: site, type, mucosa color (beefy red vs dusky vs black), height above skin, peristomal skin, presence of parastomal bulge with cough/Valsalva, effluent character and volume over 24 h.

24 Abbreviations, HPIs & References Reference

Abbreviations Master List

Sample HPI Templates

References & Sources