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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1499_Библиотеки_им_академика_М_И_Перельмана.pdf
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ABDOMEN
Abdominal shape: scaphoid, flat, distended, obese.
Pannus, including location of body folds.
Distention: soft, tympanitic, mass, organomegaly.
Presence/absence of defects, wounds, ostomy, skin abnormality.
Presence/absence of fresh surgical wounds (incisions).
Presence/absence and location of scars.
Hernias: groin, umbilical, incisional hernias.
Tenderness to palpation: location, severity.
Peritoneal signs: guarding (involuntary), rebound tenderness, percussion tenderness.
Bowel sounds: normo-active, hyperactive, tympanitic, absent.
OTHER BODY REGIONS
Lymph node regions: particularly groin, but also supraclavicular, axillary.
Hernia: former incisions, groin.
Limitations
Access to internal pathology is limited.
Cross-Reference
Liability in colorectal surgery (Ch. 2)
Patient history (Ch. 2)
Colorectal cancer screening/surveillance through Nuclear scintigraphy (Ch. 2)
COLORECTAL CANCER SCREENING/SURVEILLANCE
Overview
Symptoms are not reliable for early detection of colorectal cancer (CRC). There is therefore a need for risk-adjusted
screening programs for asymptomatic individuals to start no later than age 50, earlier in increased or high-risk individuals.
No definite guidance available about criteria to discontinue screening.
Effective screening has to be:
Based on understanding of the adenoma-carcinoma sequence: it takes 5–10 years from the first molecular change to
a clinically manifest cancer (caveat: shorter sequence in HNPCC).
Based on individual's genetic, disease- or age-dependent risk for the development of CRC.
Highly sensitive.
Practical, easy to do, cost-effective.
The term screening is only applicable to asymptomatic people; a test in the presence of symptoms should not be called
"screening" but instead, "diagnostic" evaluation.
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Epidemiology
Prevalence of polyps: 20–30% in average-risk persons 50 years of age.
First colonoscopy responsible for largest benefit of polypectomy; risk for subsequent CRC in patients with small adenoma is
not greater than average risk.
Current screening rates among average-risk population are unacceptably low: 20–50%. Contrast: > 50% of
gastroenterologists and colorectal surgeons perform colonoscopy at intervals shorter than recommended by the guidelines
not cost-effective and diverting resources from higher yielding primary screening.
Differential Risk Assessment
Low or average risk (65–75%): no risk factors, no CRC in any first-degree relatives.
Moderate risk (20–30%): CRC in one first-degree relative with age 60 years or two first-degree relatives of any
ages, personal history of curative resection of colorectal malignancy or large polyp (> 1 cm) or multiple colorectal
polyps of any size.
High risk (6–8%): FAP, HNPCC, IBD.
Screening Tools
FECAL OCCULT BLOOD TEST (FOBT)
Pros: noninvasive, easy, convenient, safe.
Cons: colon not visualized, low to moderate sensitivity/specificity, positive tests require colonoscopy and other
testing. Lack of specificity: only 2% of patients with positive FOBT have a CRC, ie, 50 colonoscopies needed to identify
1 patient with CRC, 100 colonoscopies needed to save 1 patient.
Precautions: should be repeated annually, dietary restrictions (no red meat, horseradish, vitamin C, etc).
Data: annual FOBT associated with decrease in CRC mortality of 20–33%; sensitivity for advanced adenomas or CRC
only 24%.
FLEXIBLE SIGMOIDOSCOPY
Pros: safer than colonoscopy, more convenient, no bowel prep, most commonly no need for sedation.
Cons: does not visualize entire colon, positive findings require full colonoscopy.
Precautions: should be repeated every 5 years.
Data: decrease in CRC mortality = 60% overall, 70% distal CRC; 2% of patients with normal flexible sigmoidoscopy
have a significant lesion proximal to splenic flexure.
COMBINATION OF FOBT AND FLEXIBLE SIGMOIDOSCOPY
Data: even though offering a theoretical advantage, the benefit of combining the 2 tests remains uncertain: higher detection
rate, but no proven incremental decrease in CRC mortality compared to flexible sigmoidoscopy alone (see above).
COLONOSCOPY
Pros: gold standard with full colonic visualization, therapeutic capability.
Cons: higher risk than flexible sigmoidoscopy, need for bowel prep, need for sedation.
Precautions: should be repeated every 10 years.
Data: National Polyp Study found 76–90% decreased CRC incidence with colonoscopy and removal of all visualized
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polyps compared with historical controls.
BARIUM ENEMA
Pros: full colonic visualization even in presence of nearly obstructing lesion, no need for sedation, better tolerated.
Cons: no therapeutic capability, lower sensitivity than colonoscopy, positive or uncertain findings need colonoscopic
evaluation, still needs bowel prep.
Precautions: should be repeated every 5 years.
Data: sensitivity 80–85% for colorectal cancer and 50% for large polyps (> 1 cm).
CT COLONOGRAPHY
Pros: full colonic visualization, no need for sedation.
Cons: no therapeutic capability, still needs bowel prep, higher discomfort (insufflation of air, no sedation given),
unnecessary evaluations/surgeries for incidental findings.
Precautions: interpretation and recommendations not clarified.
Data: awaiting further confirmation. Current data controversial with reports of similar sensitivity vs only moderate
sensitivity/specificity for larger lesions compared to colonoscopy. Sensitivity for smaller polyps definitely lower.
FECAL DNA
Pros: noninvasive, convenient, safe.
Cons: colon not visualized, low to moderate sensitivity/specificity, positive tests require colonoscopy and other
testing.
Precautions: should be repeated every year.
Data: Sensitivity better than FOBT; 50% for detecting invasive CRC, 15–20% for significant adenomas.
Guidelines
BASELINE SCREENING (IF NORMAL)
Goal: Detection and elimination of precursor lesions, identification of patients at risk to stratify for frequency of future
screening/surveillance.
1. Average-risk individuals, asymptomatic, non–African-American start at age 50:
a. Colonoscopy every 10 years (method of choice).
b. Annual FOBT; if positive colonoscopy.
c. Screening sigmoidoscopy every 5 years.
d. Double-contrast barium enema every 5 years.
2. Increased or high-risk individuals
specific guidelines:
a. African-American ethnicity: start screening at age of 45.
b. Positive family history (increased risk group): start at age of 40 or 10–15 years before youngest family
member (whichever comes first).
c. Ulcerative colitis: start 7 years post onset: (bi-)annual colonoscopy with multiple biopsies.
d. FAP: start in early/mid teens (vs genetic testing).
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e. HNPCC: start around age of 25 (vs genetic testing); thereafter repeat colonoscopy every 1–3 years because
of shorter adenoma-carcinoma sequence!
REPEAT COLONOSCOPY AFTER POLYPECTOMY
Goal: Detect and remove adenomata missed on the initial exam (miss rate: 10–20% of polyps = 6 mm); assess patient's
tendency to form new adenomas with advanced pathologic features.
1. Short interval (based on clinical judgment):
a. Numerous adenomata.
b. Malignant adenoma (cancerous polyp).
c. Large sessile polyp.
d. Incomplete colonoscopy or incomplete removal.
2. Three-year interval:
a. Advanced or multiple polyps (
3).
3. Five-year interval:
a. One to two small polyps (tubular adenoma).
4. No surveillance needed:
a. Hyperplastic polyps (exception: patients with hyperplastic polyposis syndrome).
REPEAT COLONOSCOPY AFTER SPORADIC CRC (NOT HNPCC/ATTENUATED FAP)
Goals: rule out synchronous/metachronous CRC; rule out true anastomotic recurrence (< 2% risk); detect and remove
adenomata missed on the initial examination; assess patient's tendency to form new adenomas with advanced pathologic
stage.
1. Around time of resection ± 6 months:
a. Full colonoscopy before resection.
b. If colon perforated/obstructed and cannot be evaluated at the time of the resection full colonoscopy to be
performed within 6 months.
2. One-year interval:
a. After the resection.
3. Three-year interval:
a. If perioperative or first postoperative colonoscopy negative.
4. Five-year interval:
a. Thereafter if normal.
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HNPCC/AFAP: annual surveillance of residual colorectum.
Follow-Up
Pathology results.
Clinical side effects of polypectomy: postpolypectomy syndrome, perforation, bleeding.
Surgery for larger polyps or cancer. Prophylactic surgery?
Secondary prophylaxis?
Cross-Reference
Bleeding per rectum (Ch. 1)
Constipation (Ch. 1)
Large bowel obstruction (LBO) (Ch. 1)
Flexible sigmoidoscopy (Ch. 2)
Colonoscopy (Ch. 2)
Contrast enemas (Ch. 2)
CT colonography ("virtual colonoscopy") (Ch. 2)
Carcinogenesis (Ch. 3)
Polyps (211.3) (Ch. 4)
Chemoprevention of colorectal cancer (Ch. 6)
FLEXIBLE SIGMOIDOSCOPY
Overview
Limited colonic evaluation: justification dependent on patient's young age (< 40 years), lack of individual risk factors for
colorectal cancer, status post complete colonoscopy within acceptable interval, status post subtotal colectomy.
One to two working ports allow for intervention, manipulation, suction/irrigation. Cold biopsy: using forceps. Hot biopsies are
generally contraindicated because of inadequate gas elimination with enemas which carries a risk of explosion!
Sedation and analgesia are commonly not needed as major flexures do not have to be passed. Success and detection rate
depend on the endoscopist's skill, time spent thoroughly inspecting the colon, and adequacy of cleansing enemas.
Alternatives
Rigid sigmoidoscopy.
Full colonoscopy.
Colonic imaging (contrast enema, CT colonography).
Indications
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Diagnostic evaluation of symptomatic low-risk individuals (< 40 years old, negative personal/family history) with symptoms
of likely distal origin, eg, bright red blood per rectum.
Intervention: biopsy, polypectomy, stenting, tattooing, to stop bleeding, for focal decompression.
Screening: in conjunction with Hemoccult test.
Surveillance of residual colon and rectum after total or subtotal colectomy.
Preparation
Two Fleet enemas right before test.
Office procedure: commonly no sedation needed.
Caveat: enemas insufficient to remove explosive gases
snare/cautery contraindicated!
Advantages
Combination of evaluation, biopsy, and (limited) intervention.
No lengthy preparation needed.
Limitations and Risks
Pathologic lesion not in reach of flexible sigmoidoscope (eg, proximal polyps and neoplasms, 20% of C difficile colitis,
etc).
Miss rate: up to 20–25% for polyps up to 1 cm.
Perforation: low risk for diagnostic endoscopy, higher in interventional endoscopy and/or preexisting bowel weakness,
eg, acute diverticulitis.
Bleeding: depending on pathology/intervention, minimal for diagnostic endoscopy.
Explosion of intestinal gas (hydrogen, methane): use of cautery in inadequately prepped colon contraindicated in
flexible sigmoidoscopy.
Size of lesions generally overestimated (magnification) need to correlate size of lesion with diameter of inserted
instruments.
Exact orientation difficult/impossible; only absolute landmark is dentate line; if location needs specification (eg, for
later surgery): tattooing of the area with India ink (1 mL in 3 separate areas on the circumference).
Characteristic Features
Pathology: melanosis coli, friability, ulcerations, edema (disappearance of vascular pattern), granular reflections ("star sky"),
polyps (diminutive, sessile, pedunculated, extramucosal), mass (mucosal/extramucosal), lipoma (extramucosal, soft
impressibility: pillow sign), diverticula, stricture, fistula, hemorrhoids.
Cross-Reference
Colorectal cancer screening/surveillance (Ch. 2)
Colonoscopy (Ch. 2)
Polyps (211.3) (Ch. 4)
Polyposis syndromes (211.3, 235.2) (Ch. 4)
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Colorectal cancer—colon cancer (153.X) (Ch. 4)
COLONOSCOPY
Overview
Complete evaluation of entire colon (and terminal ileum) with option of biopsy and intervention. Intended extent of
examination is dependent on individual circumstances (eg, previous surgeries), expected findings, patient's age, etc.
One to two working ports allow for intervention, manipulation, suction/irrigation. Cold biopsy: using forceps. Hot biopsies:
using snare and electrocautery (contraindicated with inadequate cleansing, eg, enemas only).
As the instrument has to be negotiated around angles and flexures, monitored IV sedation and analgesia are commonly
administered (even though not mandatory). Success and detection rate depend on endoscopist's skills, time spent thoroughly
inspecting the colon (withdrawal time > 6 minutes), and adequacy of bowel cleansing.
Advanced techniques:
High-resolution colonoscopy with chromoendoscopy (spraying of colon with 0.4% indigo carmine dye) is associated
with a higher detection rate for polyps and flat adenomas.
Combination with endoscopic ultrasound.
Alternatives
Limited colonic evaluation: flexible sigmoidoscopy.
Single-column contrast enema: gives a road map but does not allow biopsy, intervention.
Double-contrast enema: if colon is clean and good radiologic technique is used
similar screening sensitivity as colonoscopy.
CT colonography ("virtual colonoscopy"): also needs bowel prep. Typically done without sedation
discomfort. Findings
inside/outside colon precipitate further (unnecessary?) interventions.
Indications
Screening and surveillance per guidelines (asymptomatic individuals), clearing rest of colon before segmental intervention.
Diagnostic evaluation of specific symptoms (bleeding, distention, altered bowel habits, etc) in patient > 40 years of age or
presence of additional risk factors. Evaluation of patients with altered bowel habits and suspicion for Crohn disease (
intubation of ileocecal valve).
Intervention: biopsy, polypectomy, stenting, tattooing, to stop bleeding, for detorsion or decompression.
Contraindication: suspected perforation, acute diverticulitis (< 4–6 weeks after onset), fulminant colitis, unstable patient.
Preparation
Colonoscopy: full bowel cleansing the day before.
Conscious sedation and monitoring.
If intervention anticipated: discontinuation of anticoagulation (if possible) or switch to heparin with perioperative short-term
pausing; discontinuation of ASA/NSAIDs not mandatory but recommended if possible.
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Advantages
Combination of evaluation, biopsy, treatment, and intervention (gold standard).
Better tolerability under sedation.
Limitations and Risks
Ten percent incomplete colonoscopy: inability to reach cecum due to technical, anatomic, or patient-related issues
(pain tolerance), equipment failure:
barium enema: safe on same day unless biopsy or polypectomy performed
wait 5–7 days.
Miss rate: 20–25% for polyps < 1 cm, 6–12% for polyps > 1 cm: more likely in insufficient prep, spastic colon.
Bleeding: 0.1–0.5% (diagnostic), 1–2.5% (polypectomy).
Colon perforation: 0.1% in diagnostic endoscopy, up to 1–3% in interventional endoscopy, particularly in preexisting
bowel wall weakness; perforation requires surgical intervention unless very favorable conditions allow for conservative
management; 4 perforation mechanisms:
– With the instrument tip
often relatively small perforation.
– Bowing injury from instrument looping and overstretching of colon wall
commonly very large tears.
– Diffuse overinsufflation in weakened colon wall (eg, diverticulum).
– As result of intervention (biopsy, snare, stent).
Postpolypectomy syndrome: caused by cautery injury to colon wall pain, abdominal tenderness, often starting 1–3
days after procedure; most commonly manageable with antibiotics but perforation needs to be ruled out.
Explosion of intestinal gases (hydrogen, methane): use of cautery in inadequately prepped colon, high risk with
mannitol cleansing (sugar degradation through bacteria
increased intestinal gas production).
Size of lesions generally overestimated (magnification): need to correlate size of lesion with diameter of inserted
instruments.
Exact orientation difficult/impossible; only absolute landmarks are dentate line, terminal ileum.
Characteristic Features
Normal structures: ileum with carpet-like mucosa (small bowel villi), Peyer plaques. Appendiceal orifice. Ileocecal valve.
Cecum/ascending colon: often less clean despite otherwise good cleansing. Hepatic flexure with transparency of bluish liver.
Transverse colon (triangular shape typical but not specific). Descending/sigmoid colon. Rectum with reticular vascular
pattern. Retroflex view for distal rectum and hemorrhoids.
Most common pathologies:
Degenerative: melanosis coli, diverticula, hemorrhoids, dolichocolon (too long, tortuous), megacolon (too wide),
volvulus.
Inflammation: edema (disappearance of vascular pattern), granular reflections ("star sky"), friability, ulcerations
(diffuse vs skip and bear claw), cobblestoning, pseudomembranes, mucosal necrosis.
Growth: polyps (diminutive, sessile, pedunculated, extramucosal), mass (mucosal/extramucosal), lipoma
(extramucosal, soft impressibility: pillow sign).
Anastomosis, stricture, fistula.
Cross-Reference
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Colorectal cancer screening/surveillance (Ch. 2)
Contrast enemas (Ch. 2)
CT colonography ("virtual colonoscopy") (Ch. 2)
Polyps (211.3) (Ch. 4)
Polyposis syndromes (211.3, 235.2) (Ch. 4)
Colorectal cancer—colon cancer (153.X) (Ch. 4)
Bowel preparation/cleansing (Ch. 7)
POUCHOSCOPY
Overview
Instrumentation (rigid or flexible) of existing pouch (ileoanal pouch, continent ileostomy) for evaluation or treatment (eg,
dilation of stricture, decompression, tube insertion, etc).
Indication based on symptoms (ie, pouch dysfunction, pouchitis) or for routine surveillance of pouch and ATZ for dysplasia,
polyps, or cancer (particularly in FAP).
Circumstances dictate whether flexible or rigid instrument preferable. Sedation and analgesia are commonly not needed but
occasionally preferable in very sensitive patient (eg, traumatized perianal skin, etc).
Alternatives
Pouchogram: contrast x-ray.
Indications
IBD: every 1–3 years or when symptomatic and not responding to conservative treatment, surveillance of ATZ cuff
every 1–3 years.
FAP: every year.
Preparation
Diagnostic: possibly 1 Fleet enema right before test (if poor visibility).
Therapeutic: none.
Advantages
Combination of evaluation, biopsy, and (limited) intervention.
No lengthy preparation needed.
Limitations and Risks
Pathology missed (inadequate visibility, pocket).
Perforation: low risk.
Bleeding: depending on pathology/intervention, minimal for diagnostic.
Exact orientation difficult/impossible.
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Characteristic Features
Pathology: pouchitis, lymphoid hyperplasia (Peyer plaques), dysplasia, formation of polyps/tumor, mass (more likely in
posterior area), acute and chronic inflammation, ulcerations ( suggestive of Crohn disease if ulcerations in afferent limb),
length of efferent limb (eg, S-pouch), friability of ATZ, length and configuration of valve segment (continent ileostomy),
fistula opening.
Cross-Reference
Pouchogram (Ch. 2)
Familial adenomatous polyposis (FAP; 211.2, 235.2, V84.09) (Ch. 4)
IBD-ulcerative colitis (556.9) (Ch. 4)
"Pouchology"—the science of pouches (Ch. 4)
Pouchitis—ileoanal dysfunction (569.60) (Ch. 4)
Kock pouch dysfunction (Ch. 4)
CAPSULE ENDOSCOPY
Overview
Although the colon and upper GI tract are accessible for direct endoscopy, the small bowel in between is not. Overall, the
small bowel only rarely is the primary site of disease. Concern that the test is often overused, eg, missing indication or low
yield indication.
Alternatives
Small bowel follow-through.
CT enterography.
Ileoscopy.
Indications
Obscure bleeding while EGD and colonoscopy negative.
Evaluation of small bowel Crohn disease.
Suspicion for small bowel tumor.
Relative contraindication: stricture (particularly first-generation device may get trapped; newer development:
biodegradable capsules).
Preparation
Overnight fasting.
Potentially small bowel follow-through to rule out stricture.
Advantages