Lower GI Surgery Flashcards
What are the arterial supplies to the colorectal system
The colon is supplied by the SMA and IMA, and the rectum supplied by 3 arterial supplies:
1) Branches of SMA include
- Ileocolic artery
- Right colic artery
- Middle colic artery
2) Branches of IMA include:
- Left colic artery
- Sigmoid branches
- Superior rectal artery
3) Rectum is further supplied by:
- Middle rectal artery from internal iliac artery
- Inferior rectal artery from internal pudendal artery (from internal iliac)
What vascular anasomotoses at the watershed area of LB?
1) Marginal artery of Drummond
2) Arc of Riolan (aka Meandering artery of Gonzalez)
How to identify IMV
To the left of DJ flexure
What parts of GI tract do not have a serosa?
1) Esophagus (except the very distal part)
2) Middle and Distal rectum
What are the white lines of Toldt?
Lateral peritoneal reflections of the ascending and descending colon
Name the venous drainage of the rectum
1) Proximal rectum drains to IMV to splenic vein to portal vein
2) Middle rectum drains to iliac vein to IVC
3) Distal rectum drains to iliac vein to IVC
Where is the rectosigmoid junction?
- It is constantly located 15-18cm from the anal verge
- Found anterior to sacral promontory
- Where mesocolon and haustra terminates
What ions are absorbed and secreted by the colon?
Where in GI tract does majority of water absorption occurs?
Colon preferentially absorbs Na+
Colon preferentially secrets K+ and HCO3-
Most water absorption is by ascending colon
What kind of tumour are colorectal cancer?
Majority are endoluminal adenocarcinoma arising from mucosa.
Sometimes carcinoid tumours, lymphomas (MALT lymphoma), and Kaposi sarcoma (in HIV)
CRC site distribution
Depends on the locality, majority are on the left side
Up to 70% of colonic cancers occur in the sigmoid colon and upper rectum
However in Asian population, more right side
In Hong Kong:
1) Ascending colon (30%)
2) Sigmoid (25%)
3) Rectum (20%)
4) Descending colon (15%)
5) Transverse colon (10%)
Risk factors of CRC
<strong><em>Modifiable VS non-modifiable </em></strong>
Modifiable:
1) Diet & Lifestyle
- Smoking (higher risk for rectal cancer)
- Alcohol
- high red & processed meat (12 portion)
- high fat, low fibre
- low physical activity
2) Obesity
Non-modifiable
3) Male
4) Age >50yo (thus start screening)
- *5) Past history** of CRC or adenomatous polyps
- villosity, high grade dysplasia
- higher risk if larger polyps, plenty number
- *6) Family History (Genetics)**
- 1 first degree relatives with CRC or adeno polyp
- 2 second degree relatives with CRC
- esp diagnosed under 60yo
- *7) IBD**
- Ulcerative colitis poses more risk than Crohn Disease
- *8) Major polyposis syndromes**
- FAP
- Gardner syndrome
- Turcot syndrome
- Peutz-Jeghers
- Familial juvenile polyposis coli
- *9) Hereditary nonpolyposis CRC**
(i. e. Lynch syndrome I & II)
Pathogenesis of CRC
Two molecular pathways:
1) Chromosomal instability pathway (i.e. adenoma-carcinoma sequence)
2) Microsatellite instability pathway (i.e. Lynch syndrome)
_____________
1) Adenoma-carcinoma sequence & Knudson’s multi-hit Hypothesis
- *Normal Mucosa**
- (hyperproliferation, DNA hypomethylation)
- *-> Adenoma**
- (oncogene mutation)
- *-> Severe dysplasia**
- (allelic deletion, aneuploidy)
-> Colorectal carcinoma
Transition from normal mucosa to carcinoma is due to accumulated abnormalities of particular genes. Mutations in mismatch-repair genes cause microsatellite instability and the successive mutation of target cancer genes.
APC allele is often inherited (first hit). Hypomethylation may inactivate the normal tumour suppressor APC allele (second hit). Subsequent changes include oncogen mutation (K-ras), tumour suppressor gene inactivation (p53, LOH)
What is the evidence for adenoma-carcinoma sequence?
1) Distribution of cancers is similar to polyps
2) FAP always proceeds to cancer
3) Adenocarcinoma is seen histologically in adenomatous polyps
4) Systematic removal of polyps reduces lifetime cancer risk
5) Age incidence peaks for polyps about 5 years before carcinoma
Clinical presentation of Colorectal cancer
It may present in 3 ways:
A) Asymptomatic discovered by screening
B) Suspicious symptoms and signs
1) Constitutional Sx
2) Altered bowel habits (more common left), mucus in stool
3) Anaemia, occult blood (right side)
4) Haematochezia (left side)
5) Rectal mass or abdominal mass
6) Tenesmus, rectal pain, pencil stool (rectal)
7) Abdominal pain
8) Symptoms due to metastasis e.g. bone pain, jaundice, pleural effusion
C) Emergency Admission
1) Colonic obstruction (usually left side)
2) Perforation with peritonitis
3) Acute massive lower GI bleeding
Specific presentation of CRC in different sites
- *Right sided tumours**
- occult blood with anaemia, altered blood more common
- triad of anemia, weakness, RLQ mass
- less common obstruction or altered bowel habits due to larger luminal diameter in caecum, also more liquid stool
- *Left sided tumours**
- Hematochezia more common
- Crampy abdominal pain associated with defaecation
- common present with change in bowel habits, i.e. alternating diarrhoea and constipation
- common with narrowing of stool (“pencil stool”)
- more likely to present with colonic obstruction (due to small luminal diameter), thus distention, obstipation
- *Rectal cancer**
- Hematochezia more common
- Pencil stool
- Tenesmus, rectal pain
- Rectal mass
How does CRC spread?
Colorectal cancer spread by:
- *1) Direct extension**
- first circumferentially
- then through the bowel wall
- later invade adjacent peritoneal organs
- *2) Hematogenous**
- via portal circulation to liver (most common)
- via lumbar or vertebral veins to lungs
- also bone, adrenal mets
- *3) Lymphatics**
- regional LN (e.g. para-aortic LN)
- Virchow’s node if advanced
4) Transcoelomic
Investigations in suspected CA colon
What additional workup if rectal tumour?
- *A. Blood tests**
1) CBC - for anaemia
2) LFT, RFT (liver met)
3) CEA (for pre-op level)
4) Clotting profile, type & screen (pre-op) - *B. Complete Colonoscopy (Gold Standard)**
- Diagnosis of tumour with biopsy (genetic testing for VEGF and EGFR mutation)
- Removal of synchronous polyps
- Detection of synchronous cancer (5%)
- *C. Imaging**
1) CXR (Lung met), AXR
2) CT T+A+P or PET-CT for M staging - *D. Additional for Rectal Tumour**
1) Rigid sigmoidoscopy for accurate assessment of distance of rectal tumour from anal verge
2) Rectal protocol MRI (some uses trans-rectal USG)
- good for local staging of rectal carcinoma (T & N stage)
- assessing depth of invasion into the mesorectal fat surrounding the rectum
- determine circumferential resection margin (CRM)
What is CEA? What’s its role in CRC?
Carcinoembryonic antigen (CEA) is a glycoprotein present in primitive endoderm. Serum CEA raised in advanced CRC.
Role of CEA in CRC:
★ NOT for screening or diagnosis
i) For prognosis
ii) For baseline and recurrence surveillance after curative resection; allows early detection & thus treatment of recurrence (no proven survival benefit)
What are some causes of CEA elevation?
1) Smoking can cause mild increase
- *2) Aerodigestive tract cancer**
- CA lung
- CA stomach
- CRC
3) CA Pancreas
4) Medullary thyroid CA
What to do if colonoscopy cannot reach ileocecal valve in a CRC patient?
Perform other imaging investigations:
1) CT colonoscopy (colonography)
2) Barium enema
3) PET/CT
CRC staging systems
What is the prognosis in the TNM stage?
A) Dukes’ staging (ABCD)
- Dukes’ A: tumor within the wall of the bowel
- Dukes’ B: invades through the wall of the bowel
- Dukes’ C: regional lymph node mets
- Dukes’ D: distant mets
B) TNM staging (I to IV)
- Tis: in-situ i.e. intra-mucosa
- T1: submucosa
- T2: muscularis propria
- T3: invades through MP to subserosa
- T4: through serosa to surroundings
- N1: 1-3
- N2: 4 or more
- M1: distant met
- Stage I: T1-2, N0, M0 (90% 5-year)
- Stage II: T3-4, N0, M0 (70% 5-year)
- Stage III: N1-2, M0 (50% 5-year) = Duke C
- Stage IV: M1 (10% 5-year) = Duke D
3) Haggitt classification & Kudo classification for Tis & T1 disease (i.e. malignant polyps)
CRC surgical intervention types (generally speaking)
Curative vs Palliative
- *CURATIVE RESECTION**
1) Resection of the bowel segment with tumor
2) Adequate lymphadenectomy (12+)
3) Resection of distant metastasis (e.g. solitary liver metastasis) - *PALLIATIVE RESECTION** (when removal of all cancer tissue not possible)
1) Palliation of symptoms such as obstruction and bleeding - *PALLIATIVE NON-RESECTION**
1) Diverting Stoma
2) Bypass surgery for palliation
3) Stenting
Curative Treatment flow of CA Colon in general
- *1) Staging** via colonscopy, biopsy, CXR, AXR, PET/CT
- also do genetic testing for VEGF and EGFR mutation
2) Serum CEA level used to establish baseline
- *3) Pre-operative preparation**
- ERAS protocol
- Oral antibiotic bowel prep
- Mechanical bowel prep
- 24-hr IV antibiotics prophylaxis
- NPO to reduce stool volume and facilitate colonic manipulation
- Type and screen
- *4) Specific surgical resection** depending on the lesion
- Based on sites of CRC
- Adequate lymphadenectomy (at least 12)
- *5) Post surgical** routine management
- Pain Mx e.g. epidural
- LMWH for DVT prophylaxis
- *6) Adjuvant therapy (for stage III, IV)**
- Chemotherapy FOLFIRI (leucovorin, 5-FU, irinotecan) or FOLFOX (leucovorin, 5-FU, oxaliplatin)
- Radiotherapy
- Targeted therapy with VEGF inhibitor (bevacizumab) an EGFR inhibitor (cetuximab)
7) Follow-up surveillance
Bowel prep for colorectal resection
Preoperative “bowel prep”:
1) Golytely colonic lavage or Fleets Phospho-Soda until clear effuent per rectum
2) PO antibiotics
3) Pre-op 24-hr IV antibiotics (Zinacef, Flagyl)
Basic principles to note in curative resection of CRC
1) Adequate lymphadenectomy (at least 12)
2) High ligation of arterial pedicle
- *3) Adequate proximal & distal margin**
- at least 5cm traditionally for colon cancer
- 2cm for rectal tumour
4) Segment of resection usually determined by vascular anatomy and lymphatic drainage
5) Restoration of bowel continuity (tension-free anastomosis)
Explain margins and anastomosis in colectomy approaches
Right Hemicolectomy
- Remove: distal 10 cm of terminal ileum to proximal 1/3 transverse colon
- Anastomosis: ileum to transverse colon
- Vessels: ileocolic, right colic, and right branch of the middle colic vessel
Extended Right Hemicolectomy
- Remove: distal 10cm of terminal ileum to proximal descending colon (splenic flexure removed as it is watershed area)
- Anastomosis: ileum to descending colon
- Vessels: ileocolic, right colic, middle colic vessels (both branches)
Limited transverse colectomy
- Remove: middle part of transverse colon (not too much otherwise high tension)
- Anastomosis: remaining ends of transverse colon
Left hemicolectomy
- Remove: Splenic flexure to (entire or part of) sigmoid colon
- Anastomosis: Distal transverse colon to sigmoid colon or rectum
Sigmoidectomy
- Remove: Sigmoid colon
- Anastomosis: Descending colon to upper rectum
Elective colectomy selection for colorectal cancers
A. Caecum, Ascending Colon
1) Right Hemicolectomy
B. Hepatic Flexure
1) Extended right hemicolectomy
C. Transverse Colon (depends on site)
- *1) Extended Right Hemicolectomy** (most common)
- *2) Left Hemicolectomy
3) Transverse colectomy** if mid-transverse CA without extension to both flexures
D. Splenic Flexure Colon (controversial)
- *1) Extended Right Hemicolectomy** (most common) if lymphatic drains proximal
- *2) Left Hemicolectomy** if lymphatic drains distally
E. Descending colon
1) Left hemicolectomy
F. Sigmoid colon
1) Sigmoidectomy
G. High rectum
1) Anterior resection (TME)
H. Low rectum
1) Anterior resection (Low TME)
I. Anal verge or sphincter involvement
- *1) Abdominoperineal (AP) excision
- **with end-colostomy or ileostomy
Complications of Colectomy and LAR/APR
- *INTRA-OP**
1) Bleeding (from splenic injury, vessel injury)
2) Injury to nearby structures (spleen, duodenum, ureter)
POST-OP
A. General (cardiac, pulmonary, DVT, PE, etc)
B. Specific (EARLY)
1) Wound infection
2) AROU
3) Anastomotic leakage / deshicience
4) Intra-abdominal abscess/collection
5) Prolonged ileus
C. Specific (LATE)
- *1) Anastomotic stricture
2) Sexual dysfunction** as a result of damage of the splanchnic nerves (in rectum surgery) - *3) Urinary retention
4) LAR syndrome** (Bowel disturbance) - Faecal Incontinence
- Faecal urgency
- Frequent bowel movements with clustering
- Bowel fragmentation
- *5) Stoma Cx** (Ischaemia, Retraction, Prolapse, stenosis, skin problem, parastomal hernia)
What is Hartmann’s Procedure?
- Rectosigmoidectomy
- End descending colostomy
- Blind rectal stump
Surgical management of obstructed CA colon
After resuscitation; Drip & suck; rectal tube decompression
Depends on the side of tumour
A) If right side (ascending or transverse)
- *1) Emergency Resection**
a) Right / extended right with primary anastomosis if possible
b) Right / extended right with exteriorization of bowel ends - *2) Emergency Non-resection**
a) Iliocolic bypass
b) diverting stoma
B) If left side
- *1) Emergency Resection**
a) 2-stage procedure e.g. Hartmann Procedure
b) Segmental resection with on-table irrigation and primary anastomosis (“1-stage procedure”)
c) Subtotal colectomy if caecal perforation - *2) Emergency Non-resection**
a) Stenting
b) Bypass surgery
c) Diverting stoma –> 3-stage approach
b) Hartmann procedure (if sigmoid / high rectum)
- > primary anastomosis later
- *2) 1-stage procedure (can consider for left side)**
a) Segmental resection (left hemicolectomy, sigmoid colectomy or anterior resection) with on table irrigation and primary anastomosis
b) Subtotal/total colectomy and primary anastomosis
B) Emergency Surgical Non-resection
1) Endoluminal stenting (usually left side tumour)
- *2) Diverting stoma**
- if unresectable
- as 3-stage approach for left sided obstruction (not preferred)
3) Bypass surgery (e.g. iliocolic bypass in right side tumour)
Compare the emergency surgical resection approaches for left sided CRC (pros & cons)
1) 3-stage procedure
+ treatment of choice for patients who are unfit for resection at presentation
+ anastomosis and its attendant risk of failure are avoided in the 1st stage operation
- decreased long term survival (higher cumulative mortality and morbidity)
- 50% patients never have colostomy closed
- out of favour
2) 2-stage procedure e.g. Hartmann (preferred)
+ early removal of tumour, relieve obstruction
+ anastomosis and its attendant risk of failure are avoided in the 1st stage operation
- reanastomosis can be very difficult, ~10% mortality
- up to 40% of patients did not have bowel continuity restored due to various reasons
3) 1-stage procedure
+ Single procedure
+ avoidance of stoma
- higher risk of anastomotic leakage (5-10%)
- Loop ileostomy can be fashioned to allow the primary anastomosis to heal
Why is primary anastomosis not preferable in emergency management of left sided CRC?
When we decide to do an emergency surgery on left sided CRC:
1) Patient is usually weak, malnourished, and dehydrated
2) Proximal colon is usually edematous and unhealthy, with its blood supply easily obliterated
3) Heavy bacterial and faecal load in proximal colon due to obstruction. Without proper bowel preparation, easily cause post-op infection
4) The ileocaecal valve remain competence, thus a close loop obstruction might be formed after surgery, causing perforation of large bowel
- > all these make an anastomosis very risky
Functions of metallic stent in colorectal cancer
Inserted under endoscope (sometimes with fluoroscopic guidance), for left sided CRC as:
- *1) Definitive palliation** in unresectable CRC
- thus avoid surgery in patients unfit for GA
- avoid stoma
- *2) As a bridge to surgery (convert emergency to elective)**
- Avoids emergency surgery with insufficient bowel preparation; avoid stoma
- Buys time for Elective operation for better workup, staging, and bowel preparation
- Lower operative morbidity and mortality
Site of stenting for CRC obstruction
Most commonly performed for left sided tumours, at:
- sigmoid (60%)
- upper rectal (20%)
- descending colon (15%)
Technically difficult for proximal (right sided) tumours
Advantage of CRC stenting
1) Rapid relief of obstruction
2) More comfortable, less invasive
- *3) Avoids emergency operation and stoma**, thus lower morbidity & mortality
- can be definitive palliative or bridge to definitive surgery
- *4) More cost effective**
- shorter hospital stay
- cheaper (cf. stoma care cost)
Complications of stenting in CRC
- *1) Re-obstruction** (15%) from:
- tumour ingrowth or overgrowth
- faecal impaction
- stent migration
- *2) Stent migration** (10%), presenting as:
- Re-obstruction
- Spontaneous expulsion
- No symptom
- *3) Bowel perforation** (7%)
- occur during the procedure or within 3 days post-stenting
- causes peritonitis
- Tumour upstaging due to peritoneal met
4) Fistula formation
Management of stent re-obstruction in CRC
Depends on the causes:
- *1) Tumour in- or overgrowth**:
- laser and restenting
- *2) Faecal impaction:**
- enema lavage
- *3) Migration**
- mostly do not need intervention
- Restenting
- Endoscopic removal
- Conversion to surgery
Things to avoid in endoluminal stenting of CRC
Avoid:
1) Balloon Dilatation of stent (due to perforation risk)
2) Concomittant preoperative Chemo-RT in CA rectum (due to perforation risk)
3) Right sided CA colon due to difficulty of deployment
4) Mid to low CA rectum due to pain and urgency
Adjuvant therapy for CA colon (indication, choice)
- *Indications:**
- stage III or above (Duke C or above)
- stage II who have inadequate lymph node retrieval (<12) or with unfavorable characteristics
- *Choice:**
1) Chemo - XELODA (capecitabine, oxaliplatin)
- FOLFIRI (Leucovorin, 5-FU, irinotecan)
- FOLFOX (Leucovorin, 5-FU, oxaliplatin)
2) Targeted therapy (for stage IV)
- VEGF inhibitor (bevacizumab)
- EGFR inhibitor (cetuximab)
+/- 3) RT for rectal CA
Unfavourable characteristics of CA colon
Unfavorable characteristics include:
Histology
1) poor differentiation
2) mucinous or signet-ring pathology
3) aneuploid nuclei
Lab Ix
4) Markedly elevated CEA (poor prognosis if >5ng/mL)
Gross behaviour
5) venous or perineural invasion
6) multiple lymph node involvement
7) pericolonic tumor deposits
8) bowel perforation
(If stage II with unfavourable characteristics, then consider adjuvant therapies)
Pros and Cons of pre-op or post-op RT for CRC
Radiotherapy for CRC:
+ reduce local recurrence rates
- no survival benefits
- cannot reduce distant mets
Preoperative
+ Can downstage tumour, thus increase curative resection chance
+ High Compliance
+ Irradiated bowel is all resected at surgery
- patients with earlier disease might be included
- Makes bowel friable and increases fibrosis in the mesorectum in rectal surgery, making the planes more difficult to dissect and total mesorectal excision more difficult
Postoperative
+ Early disease excluded as pathology known
+ Does not delay surgery
+ Planes easier to dissect in total mesorectal excision
- Small bowel more likely to be in the field
- Prolonged course
- May be delayed by surgical complications
- Irradiated bowel is left in and may result in radiation colitis
- Compliance is lower as a result of postoperative morbidity
Follow up after CRC surgery
Followup is crucial in the first 2-3 years after surgery, when 90% of recurrences occur:
1) Physical Exam
- *2) CBC LFT CEA CXR FOBT** monitoring
- rising CEA levels should prompt a CT T+A+P
- *3) Surveillance colonoscopy**
- first year after resection
- then every 3 years until negative
- then every 5 years
Principles of CA rectum surgery
1) Resection of segment containing the tumour
- *2) Adequate CRM** (circumferential resection margin) by TME (total mesorectal excision)
- remove the rectal mesentry
- because rectal cancer (lower 2/3) spread via lymphatics in the mesorectum
- *3) Adequate Distal margin**
- must be negative
- narrow distal margin (2 cm) is adequate provided mesorectal dissection is performed
- distal margin can be <2 cm in patients with distal tumors to preserve continence
- *4) Sphincter & autonomic nerve preservation**
- preserve continence & urogenital functions
5) Adequate Lymph node clearance
6) High ligation of the arterial pedicle (IMA)
CA rectum surgical approach selection
Depends on distance from anal verge & local T stage:
- *A. 0-5cm (distal third)**
- *T1:** Local excision
- *T2:** Local excision + neoChemoRT
- *T3+:** APR; if >4cm then can consider ultra-LAR + TME & proximal diversion
B. 6-10cm (middle third)
T1N0: Local excision or LAR
T2N0: Local excision + neoChemoRT; or LAR
T3+ or N+: LAR + TME & proximal diversion ± neoChemoRT
if incontinence or sphincter involvement: APR
C. 11-15cm (proximal third)
T1/T2: Local excision
LAR ± proximal diversion ± neoChemoRT
_______________
D. Hartmann’s operation
- Patients with poor sphincter function
- Emergency situation when a primary anastomosis is not safe
Explain the CA rectum surgical approaches
- *Local excision (transanal full thickness excision)**
- Traditional trans-anal excision or
- Transanal Endoscopic Microsurgery (TEM) or TransAnal Minimally Invasive Surgery (TAMIS) techniques
- For T1 lesions (or T2 tgt with neoChemoRT)
- *Anterior resection**
- Resection of rectum with colorectal anastomosis
- *Lower Anterior Resection (LAR)**
- Resection of rectum with colorectal anastomosis
- mobilization down to distal rectum and anastomosis at the level below the peritoneal reflexion
- *Abdominoperineal resection (APR)**
- Synchronous abdominal and perineal resection
- Permanent colostomy
- For distal 1/3 disease or sphincter involvements
How did “anterior resection” get its name?
Because the resection of rectum is anterior to the sacral promontory
What should be done for low (e.g. coloproctostomy) or tenuous anastomosis in CA rectum surgery?
Proximal diversion by a “defunctioning stoma” (e.g. loop colostomy, loop ileostomy) for high leaking risk anastomosis (e.g. low or tenuous).
If primary anastomosis must be performed, try leak testing in the operating theatre.
Why neo-adjuvant therapy in CA rectum
1) Downstage the tumour
2) Reduce local recurrence
3) Preserve sphincter function
4) Preoperative therapy is associated with similar results with significantly less toxicity than postoperative therapy
Contraindications of CRC liver met resection
Resection margin of CRC liver mets?
What is the 3-year survival after resection?
Contraindication:
- more than 5 mets
- other distant mets
- positive portal/celiac LNs
Resection margin = 1cm
3-year survival = 33%
What is a diverticulum? How is it classified?
A diverticulum is an abnormal outpouching of a hollow viscus into the surrounding tissues. Classified into:
1) True diverticulum: contains all layers of the wall of the viscus, e.g. Meckel’s diverticulum
2) False diverticulum, only some layers present, e.g. colonic diverticulum
Pathogenesis and risk factors of Diverticulosis
- *Pathogenesis:**
- Increased intraluminal pressure cause inner layer of colon bulge through focal sites of weakness where mesenteric blood vessels pass between muscles of the taeniae coli
- *Risk factors:**
- Low-fiber diet
- Constipation (which increases intraluminal pressure)
- Positive family history
- Old age
Common site of diverticulosis in HK
Most common location is Sigmoid colon
Righ sided diverticulosis is also common in Asians (therefore colonoscopy is better than sigmoidoscopy to visualise diverticulosis in HK)
Management of uncomplicated diverticulosis
- *1) Dietary advice:**
- High fiber diet (e.g. bran, psyllium)
- Low fat diet
- healthy lifestyle
Complications of diverticulosis (& diverticulitis)
- *1) Painless lower GI Bleeding**
- due to rupture of vasa recta
- usually stops spontaneously
- *2) Diverticulitis**
- when faeces are impacted in diverticulum, causing inflammation and bacterial overgrowth
- Acute abdominal pain
- Constipation or diarrhea, fevers
- 3) Complications of diverticulitis:*
- *i) Abscess formation**
- *ii) Fistulization**
- Colovescial fistula most common (Pneumaturia or fecaluria)
- Colovaginal fistula in women (expulsion of gas or feces from the vagina)
- Rarely, colocutaneous fistula, coloenteric fistula
- *iii) Stricture +/- Obstruction**
- due to chronic inflammation and thickening of bowel wall
- *iv) Colonic perforation**
- leads to peritonitis
Diverticulosis & Cx investigations
Dx of unCx diverticulosis:
- *1) Barium enema
2) Colonscopy** (better than sigmoidoscopy as right sided diverticulosis is common in Asian) - *3) CT colonoscopy**
Dx of diverticulitis
1) Contrast CT abdomen & pelvis
- *2) Avoid immediate colonoscopy**
- colonoscopy 6-8 weeks later to r/o malignancy
Dx for diverticular bleeding:
1) OGD to r/o upper GI bleeding; colonoscopy
- *2) Mesenteric Angiography, CT angiogram
3) Tc99m tagged RBC scan
4) intra-operative endoscopy**
Diverticulitis classifications
Hinchey Classification - guides treatment
- *I - Localised abscess** (para-colonic)
- Conservative Mx with antibiotics, bowel rest, monitoring
- even as out-patient
- *II - Pelvic abscess**
- IV antibiotics, bowel rest, monitoring
- Image guided percutaneous drainage
- consider surgery
- *III - Purulent peritonitis** (the presence of pus in the abdominal cavity)
- IV antibiotics, bowel rest, monitoring
- surgery
- *IV - Feculent peritonitis**
- IV antibiotics, bowel rest, monitoring
- surgery
Management and FU of diverticulitis
Depends on clinical status and Hinchey classification
1) Fluid resuscitation if necessary; Bowel rest (NPO) & Monitoring
2) PO or IV antibiotics (Hinchey II)
3) Percutaneous drainage if abscess (Hinchey II)
4) Consider EOT if non-responsive or Hinchey III IV:
i) 1 stage (resection + primary anastomosis)
ii) 2 stage Hartmann: resection + 1 anas + stoma; closure of stoma
iii) 3 stage: diverting stoma; resection; primary anastomosis
iv) or the new Laparoscopic peritoneal lavage (LPL)
5) CLN 6-8 weeks after diverticulitis to r/o cancer
6) Consider elective “Interval colectomy” after diverticulitis
Indications of emergency surgery for diverticulitis with perforation
What types of operations is there? Which one has lowest morbidity
First line is resus + IV antibiotics ± drainage. Consider emergency resection (hartmann or 2 or 3 stage) or LPL (lap per lavage) if:
1) Non responsive to antibiotics
2) Clinically unstable
- *3) Hinchey Class III, IV**
- generalized purulent peritonitis (III)
- gneralized faecal peritonitis (IV)
========================
Three types of operation:
1) Diverting colostomy and abscess drainage (first of three-stage approach)
2) Hartmann’s procedure (first of two)
3) Resection with colonic wash-out and primary anastomosis (one stage).
After uncomplicated diverticulitis (unoperated), who should undergo interval colectomy?
- most diverticulitis resolve with IV antibiotics
- 85% do not recur
- thus “interval colectomy” is not mandatory, but consider for:
i) complicated disease
ii) Persistent symptom after disease; repeated diverticulitis
iii) Immunocompromised, DM, or young patient
Management of diverticular bleeding
1) Resuscitation & transfusion if needed; 85% most spontaneously subsides
- *2) Colonoscopy hemostasis** with:
- adrenaline injection
- endoclips
- *±3) Further localization of bleeding origin** (when colonoscopy fails)
- mesenteric angiogram (for >1mL/min)
- RBC scan (for 0.1mL/min)
- *±4) Urgent colectomy if life threatening bleeding**
- subtotal colectomy with ileostomy or
- total colectomy with ileorectal anastomosis
Indications of urgent colectomy for diverticular bleeding
- Unstable hemodynamic despite adequate resuscitation
- Excessive blood transfusion (> 6 units)
- Frequent re-bleeding
- On anticoagulant
Fistulization in Diverticulitis
Often between colon and other organs:
- *1) Colovesical fistula** (most common)
- pneumaturia, fecaluria
- often in women with previous hysterectomy
- *2) Colovaginal fistula**
- gas or faeces from vagina
- often in women with previous hysterectomy
- *3) Colocutaneous fistula** (rare)
- *4) Coloenteric fistula** (rare - may result in corrosive diarrhoea)
Management of diverticular fistula
1) Antibiotics & drainage to control sepsis
2) Elective colon resection & repair of adjacent structure
Which vessel provides blood supply to the appendix?
Appendiceal artery which is a branch of the ileocolic artery
Position of appendix
1) Retrocecal / retrocolic (60%): behind cecum or even ascending colon (if long enough)
2) Pelvic (30%): suspended over the pelvic brim
4) Subcecal (2%)
4) Pre-ileal (1%)
5) Post-ileal (0.5%)
Appendicitis epidemiology
Prevalence: most common urgent surgical procedure
Age: highest incidence in 20-30yo
Pathogenesis of acute appendicitis
1) Lumen of appendix is first obstructed by:
- hyperplasia of lymphoid tissue
- fecalith
- foreign body
- rare causes e.g. parasites, carcinoid tumour
2) Obstruction causes stasis of fluid, which promotes bacterial overgrowth and inflammation
3) Distention of inflammed appendix might compromise blood supply, causing ischemia, necrosis, and even perforation
Acute appendictitis presentation
- *Start with Alvarado Score (total 10):**
1) RLQ Pain & tenderness (2)
2) Pain migration (from peri-umbilical or even LLQ to RLQ)
3) Rebound tenderness, tenderness, board like rigidity
4) Anorexia (& Ketonuria)
5) Nausea, Vomiting
6) Fever
7) Leukocytosis > 10,000 (2)
8) Neutrophilia, with left shift of leukocytes
Plus extra signs:
+ Rovsing’s sign (press LLQ, pain in RLQ)
+ Obturator sign (pain when internal rotation of the thigh)
Plus specific presentation based on location of appendix:
+ Iliopsoas sign (if retrocecal; pain when right hip extension in left lateral decubitus)
+ Periappendiceal abscess or phlegmon as anterior bulging in PR (if pelvic)
+ Diarrhoea (if pelvic, due to rectal irritation; or retroileal from ileum irritation?)
+ Frequency, pyuria, haematuria, dysuria (if pelvic, due to bladder irritation)
Where is the McBurney’s Point? What is it?
It is 2/3 from the umbilicus to right ASIS, indicating the location of the base of the appendix
It is displaced in:
1. Pediatrics (mid point from umbilicus to right ASIS)
- Gestational (point shifts upwards and lateral due to displacement by fertile womb)
- Situs Inversus
Explain the migration of pain in acute appendicitis
Migration of dull peri-umbilical (sometimes even LLQ) pain to sharp RLQ pain
It indicates the change from the midgut visceral pain (sympathetic nerve T10, due to inflammation of the appendix itself), to the peritoneal pain (somatic nerve; i.e. intercostal nerve, due to irritation to visceral peritoneum by continuous distension of appendix)
Diagnosis and Ix in suspected appendicitis
- *1) Clinical diagnosis mostly**
- likely if Avarado score ≥5
- definite if Avarado score ≥9
Supportive Lab tests (same for acute abdomen)
2) CBC shows leucocytosis > 10,000 & Left shift (neutrophilia)
- *3) Urinalysis**
- rule out UTI or stones or urological causes
- Pyuria, albuminuria, and hematuria in bladder irritation from appendicitis
- *4) RFT, electrolyte**
- note dehydration from vomiting or poor oral intake
Imaging Ix (supportive)
- *5) US** may be helpful if uncertain about the diagnosis
6) Consider CT (when US failed e.g. due to obese)
7) Consider MRI (when US failed e.g. in pregnant lady or child)
Does abnormal urinalysis rule out acute appendicits?
No
Mild pyuria and haematuria is common in acute appendicitis from pelvic inflammation which causes ureteric inflammation
US findings of acute appendicitis
1) Aperistaltic, noncompressible, distended appendix (7mm or greater outer diameter)
2) Thickened and oedematous appendiceal wall with distinct wall layers (target appearance if axial)
3) Periappendiceal fluid collection
4) Appendicoliths or Fecoliths
Treatment of acute appendicitis
- *0) General support**
- fluid resuscitation
- NG tube suction if ileus
- analgesics
1) Antibiotics
- If uncomplicated, pre-op antibiotics
- if perforated or gangrenous, pre-op until 3-5 days post-op with normal WBC
2) Appendicectomy (laparascopic or open)
What are the open appendicectomy incisions
- *1) Gridiron** or McBurney incision
- perpendicular to ASIS-umbilical line
- *2) Lanz incision**
- along skin tension line, thus better cosmesis
- *3) Rocker Davis incision**
- horizontal
- medial extension: Fowler Weir
- lateral extension: Rutherford Morrison
Complications of acute appenidicitis
1) Gangrenous appendicitis, Perforation, Peritonitis, septic shock
2) Appendicular abscess, appendiceal mass
3) Ileus
4) Pelvic abscess
- *5) Portal pylethrombophlebitis**
- septic portal vein thrombosis
- from E. coli
Complications of appendicectomy
General vs Specific
Specific:
1) Surgical site infection (commonest), wound abscess
2) Ileus, increased risk of adhesive SBIO in future
3) Appendiceal stump leak, Enterocutaneous fistula
4) Stump abscess
5) Stump appendicitis
6) Increased incidence of right inguinal hernia (damage to ilioinguinal nerve), incisional hernia
7) Injury to surrounding organs (SB, caecum, fallopian tube)
How would you prepare a patient for an open appendicectomy?
How would you perform an open appendicetomy?
1) Informed consent
- *2) NPO, IVF, IV Antibiotics, foley for U/O if needed**
- Cefuroxime (broad spectrum) and Flagyl (anaerobe cover)
3) Prophylactic antibiotics
- *4) GA, supine position, skin cleaned and draped**
- expose the RLQ including the right ASIS, umbilicus and midline.
- *5) Lanz incision, layered dissection**
- centred over McBurney’s point
- perpendicular to line from umbilicus to ASIS
(alternative: Gridiron which is less cosmetic but easier to extend)
6) Norfolk and Norwich self-retaining retractor, layered dissection
- *7) Peritoneum held up with two artery forceps** and divided with a scalpel
- Care is taken not to damage any underlying loops of bowel
- Peritoneal swab x microscopy + C/ST (esp if perforated)
- *8) Inspection to r/o other pathology**
- caecum, SB for other pathology e.g. caecal neoplasm or Meckel’s
- ovaries and fallopian tubes to r/o PID, pelvic absvess, ovarian cyst complications
- *9) Mobilise caecum** to reveal appendix
- identify by following the taenia coli to base of appendix
- if retrocecal, may need to divide the lateral peritoneal attachments of caecum
- confirm appendicitis, look for gangrenous change or perforation
10) Mobilization of appendix. Hold appendix with a pair of Babcock’s forceps and avoid perforating it
11) Mesoappendix is divided between artery forceps and secured with 2/0 Vicryl ties to skeletonize the appendix and free it to its base (anterograde dissection)
12) A straight crushing clamp is applied across the base and replaced 5 mm distally. After applying a 0 Vicryl tie in the form of a surgeon’s knot to the base, divide the appendix flush to the clamp using a scalpel
- *13) Pouting mucosa edge of the appendix base is cauterised with diathermy**
- kill mucosal cells to prevent mucocele formation and reduce the bacterial load
14) Abd cavity is then washed out with warm saline
15) Drain if needed, to pelvis
16) Haemostasis
17) Wound closed
How to take out a difficult appendix?
Expect a difficult operation if the history is long and if an appendix mass is present. There are several techniques to help:
1) Enlarging and extending the incision
2) Assistant for retraction
3) In a true retrocaecal appendix, the caecum can be mobilized by dividing its lateral peritoneal attachments as for a right hemicolectomy
4) Removing the appendix retrogradely (base first)
5) In the presence of an abscess and being unable to find the appendix, placing a large size Robinson drain into the abscess, washing out the abdomen with saline and closing it
What would you do if the appendix were normal during an EOT for suspected acute appendicitis?
If the appendix were normal looking, I would need to search for other possible causes:
1) In a woman, look at the right fallopian tube and ovary
2) Inspect the terminal ileum and palpate for any thickening. This might indicate Crohn’s ileitis or tuberculous ileitis depending on background
3) The small bowel is run to examine for a Meckel’s diverticulum or for any inflamed mesenteric lymph nodes (mesenteric adenitis)
- If there were an inflamed Meckel’s diverticulum this would need to be resected with a short segment of adjacent normal bowel, and a primary interrupted extramucosal anastomosis performed
4) Inspect the large bowel (to look for sigmoid diverticulitis)
5) Palpate posterior abdominal wall, ascending colon, liver edge and gallbladder fundus (for cholecystitis). Look for bile-stained fluid suggesting a perforated duodenal ulcer
What to do if appendix if perforated at its base?
1) Limited caecal resection if possible
2) Limited right hemicolectomy
What is an appendiceal mass
aka Appendiceal phlegmon:
An appendiceal mass is an inflammatory mass consisting of the inflamed appendix, its adjacent viscera, and the greater omentum. (cf. abscess is pus containing).
It often presents as a palpable mass days following the onset of symptoms
Management of appendiceal mass
When would EOT be needed?
An appendix mass is usually treated conservatively:
- Bed rest
- IV antibiotics
- Serial examination to monitor clinical response
- Interval appendicectomy at 6 weeks
EOT is indicated if:
1) The mass becomes tender or enlarges
2) Uncontrolled Sepsis
3) Development of complication e.g. peritonitis, ileus, obstruction
DDx of appendiceal tumour
1) Carcinoid tumour (most common)
2) Adenocarcinoma
3) Malignant mucoid adenocarcinoma (may cause pseudomyxoma peritonei if the appendix ruptures)
What is a carcinoid tumour?
What are the common sites
Carcinoid is a tumour that arises from neuroendocrine cells i.e. Kulchistsky cells –> Secretes serotonin
Common sites “AIR”:
1) Appendix (most common)
2) Ileum
3) Rectum
4) Bronchus
5) Other sites e.g. stomach, duodenum, jejnum, colon, pancreas, thymus, ovary, testis
Clinical features of carcinoid tumour
Depends on position of tumor:
1) Mostly asymptomatic
- *2) Abdominal pain, GI bleeding
3) SBO** due to severe mesenteric fibrosis - *4) Intussuception**
- *5) Carcinoid syndrome** from serotonin and vasoactive peptides
- Bronchospasm
- Flushing of skin
- Diarrhoea
- Right side heart failure, TR, PS (as lung filtes the vasoactive peptides)
- *6) Pellagra-like symptoms** from decreased niacin production
- Diarrhoea
- Dermatitis
- Dementia
Wht does carcinoid syndrome not seen in all carcinoid tumours?
What does it indicate?
Carcinoid syndrome (“Be FRD”) = bronchospasm, flushing, right heart failure, diarrhoea due to serotonin released from carcinoid tumour
However the liver degrades serotonin to 5-HIAA if the tumour drains into the portal vein.
Therefore, presence of carcinoid tumour indicates possible:
- liver mets
- retroperitoneal disease draining into paravertebral veins
- primary tumour outside the GI tract
Management of carcinoid tumour
- *1) Surgical excision** of primary tumour and liver metastasis
- right hemicolectomy if tumour >1.5cm
- appendicectomy if appendicular tumour <1.5cm, with no serosal or cecal involvement
2) Chemotherapy for advanced disease
- *3) Medical therapy** for palliation of carcinoid syndrome
- Octreotide (somatostatin analogue)
- Anti-serotonin drug
Classification of anal fistula
i. e. the Parks Classification
1) intersphincteric
2) transphincteric
3) suprasphincteric
4) extrasphincteric
Site of anorectal abscess
1) Ischiorectal 60%
2) Perianal 20%
3) Intersphincteric 18%
4) Supralevator 2%
Colorectal adenoma endoscopic classifications (based on endoscopic appearance)
Paris Classification
**_I = Protruded Lesion_ (polyp)** p = pedunculated (base is narrow with mucosal stalk) sp = subpedunculated s = sessile (base and the top of the lesion have the same diameter)
**_II = Flat lesion (height less than one-half the diameter of the lesion)_** a = flat elevated b = flat c = mucosal depression IIa/IIc = flat elevated with central depression IIc/IIa = depression with elevated edge
-> depressed lesion particularly likely to harbor high-grade dysplasia or be malignant
Distribution of IBD
Ulcerative Colitis:
- Rectum is always involved, while colon is involved partially or completely in a continuous manner:
- *1) Proctitis, proctosigmoiditis** (10%)
- only rectum
- *2) Left sided Colitis** (40%)
- rectum plus descending colon
3) Extensive colitis, pancolitis
4) Rarely, the distal ileum might be involved, aka “Backwash ileitis”
B. Crohn’s DIsease:
Skip lesions that could involve the entire GI tract; 40% rectal sparing, anal involvement is common
1) Ileocolic (most common)
2) Small bowel
3) Colonic
4) Pan-enteric (from mouth to anus)
Treatment of volvulus
- *Depends on sigmoid VS caecal**
- *SIGMOID**
- *0) General therapy**
- NPO, TPN, oxygen
1) Start with Sigmoidoscopy decompression
± Placement of rectal tube (flatus tube) for decompression
- *2) If uncomplicated:**
- Discuss early elective sigmoidectomy (redundant part) with primary anastomosis
- aim at preventing recurrence
- *3) If complicated** with peritonitis, bowel ischemia (or failed sigmoidoscopic decompression)
- emergency Hartmann procedure (rectosigmoid colectomy, end descending colostomy, blind rectal stump)
- *CAECAL**
- *1) Emergency surgical reduction** required:
- Right hemicolectomy with primary anastomosis or ileostomy
