Colorectal Surgery Flashcards
Describe the two sphincters of the rectum
- Internal -> contracts at rest and principle response is to relax
- External -> stimulated during increase in intra-abdominal pressure
Describe the type of epithelium of the rectal canal
From anal canal and travelling upwards: loose appendages (hair follicles, sebaceous glands) at the skin, becomes columnar epithelium
Describe the bacteriology of normal GI tract
- Upper GI is sterile
- Midgut - aerobes
- Hindgut - anaerobes
What structures does the inferior mesenteric artery (IMA) supply?
1/3 of distal transverse colon, splenic flexture, descending colon, sigmoid colon and rectum
At what vertebral level does the inferior mesenteric artery (IMA) arise?
Branches off abdominal aorta at L3
What is the innervation of the hindgut?
Nerves via the inferior mesenteric plexus
Name the nerves which provide parasympathetic innervation to the hindgut?
Pelvic splanchnic nerves
Name the nerves which provide sympathetic innervation to the hindgut?
Lumbar splanchnic nerves
Give an example of a tumour of the hindgut
Colorectal cancer
Give an example of inflammation of the hindgut
Ulcerative and Crohn’s disease
Give an example of degeneration of the hindgut
Diverticular disease
Give an example of an abnormal function of the hindugt
Constipation, incontinence, IBD
Give an example of a congenital abnormality of the hindgut
Atresia, Hirschsprung’s disease
What do problems with the hindgut usually present with?
- Change in bowel habit/continence
- Bleeding
- Pain (abdominal)
- Non-intestinal manifestations – can affect eyes, joint, skin, blood
What is visceral pain?
Gut pain (visceral) poorly localised pain, but in the regions of the arterial supply of the structure, afferent nerves (in splanchnic) are conveyed along those vessels – i.e. if in location of midgut, look at the arteries that supply those structures
Describe visceral pain
- Pain receptors in smooth muscle
- Afferent impulses run with sympathetic fibres accompanying segmental vessels (CP, SMA, IMA)
- Poorly localised
What investigations are used for visualisation of the large bowel?
- Colonoscopy
- Flexible/ rigid sigmoidoscopy +/- barium enema
- CT colonography
What are high risk features of presentation of colorectal cancer?
- Persistent change in bowel habit (>6 weeks)
- Persistent rectal bleeding without anal symptoms
- R sides abdominal mass
- Palpable rectal mass
- Unexplained iron deficiency anaemia
What are the investigations of colorectal cancer?
- Endoscopy (colonoscopy and biopsy)
- Contrast imaging- barium enema
- CT/ CT colonoscopy
- MRI
What are the treatment options for colorectal cancer?
• Medical vs. surgical
• Endoscopic vs. invasive
• Laparoscopy vs. laparotomy
• Consider:
o Resection
o Restoration of continuity
o Preservation of function
o Faecal diversionWhat are the requirements for a successful bowel anastomosis?
- Tension free
- Well perfused
- Well oxygenated
- Clean surgical site
- Acceptable systemic state
Name two surgeries that are guided by pathology of arterial supply
- Bowel anastomosis
* Faecal diversion (stoma)
Name seven possible complications of faecal diversion (stoma) surgery
- Anaesthetic related
- Bleeding
- Sepsis
- VTE
- Anastomotic breakdown
- Small bowel obstruction
- Wound
