Principles of GI tract, hepatobiliary + pancreatic surgery Flashcards
What are Halsted’s principles?
- Gentle tissue handling
- Correct tissue apposition
- Minimal tension
- Obliteration of dead space
- Strict asepsis
- Meticulous haemostasis
- Preservation of blood supply
How would you perform gentle tissue handling?
- Treat the tissues you are working on as if they were your own
- Make an incision of sufficient size
- Allows thorough exploration
- Makes surgery easier
- Reduces tissue trauma
- Hands for gut - avoid excessive handling = ileus
- Keep tissues moist
- Stay sutures
- Use scalpel for initial incision into gut - extend with scalpel or metzenbaum scissors
- Liver + pancreas are especially fragile / sensitive
What abdominal structures / organs do you need to evaluate in an exploratory coeliotomy?
What order should you look at them in?
1* Parenchymatous organs first = liver, spleen, pancreas, right kidney + adrenal, left kidney + adrenal
2* Intestines - stomach, duodenum, colon, caecum, ileum, jejunum, mesenteric lymph nodes
3* Bladder + uterus, reproductive tract (if present)
4* Anything else specific to the patient’s problem
How do you perform meticulous haemostasis?
- Better to avoid haemorrhage if possible - Don’t cut major blood vessels!
- Arrest haemorrhage as quickly and completely as possible = Ligatures + Electrocautery
- Incise least vascular part of intestine = Halfway between greater and lesser curvatures of stomach
What are problems with haemostasis of the liver?
- Extremely vascular
- Hepatopathy can cause coagulopathies
- Pringle manoeuvre = temporary occlusion of hepatic blood flow (15 mins)
What are problems with haemostasis of the pancreas?
- Very vascular + fragile
- Electrocautery can cause pancreatitis
= Guillotine technique with encircling ligature, blunt dissect between lobules + individually ligate vessels + ducts
Why can’t you ligate the cranial rectal artery in dogs?
- It is the only blood supply to rectum = rectum will go necrotic if ligated
Regarding preservation of blood supply, how would you assess intestinal viability?
- Subjective criteria
-Colour
-Presence of arterial pulses
-Ongoing peristalsis - Objective criteria
-Pulse oximetry
-Doppler ultrasound
-Fluorescein dye and Woods lamp
What is the problem with oesophageal blood supply?
How would you preserve this?
- Segmental blood supply
- Rich submucosal plexus
- Preserve this by:
- Avoid excessive cautery
- Handle tissue gently
- Place sutures carefully
When performing strict asepsis what should be considered?
- Gut lumen is contaminated -Stomach relatively sterile +
Increasing bacterial population and proportion of anaerobes as you move down gut - Liver has resident population of clostridia
- Stay sutures to immobilise tissues - Oesophagus + Stomach
- Discard contaminated instruments and gloves before abdominal closure
- Lavage abdomen before closure =
- 1-3L warm sterile saline
- NO antibacterials or disinfectants
- Suction removal
Why would you perform prophylactic antibacterials?
- Must be present in tissues when contamination occurs
- Clavulanate-amoxicillin for general prophylaxis
- Metronidazole for anaerobes
- Amoxicillin + cefazolin actively excreted in bile
Tension is not usually a problem in intestinal surgery,
Most of intestine is highly mobile.
What are the 2 major exceptions?
- Oesophagus - relatively immobile so anastomoses can be difficult
- Colon during subtotal colectomy
What are the 2 main methods of making intestinal
incisions to allow accurate tissue apposition?
- Longitudinal incision, longitudinal closure
- Longitudinal incision, transverse closure
- avoid transverse incisions + closure
How fast does most of the GIT heal by?
- 75% of normal strength within 14 days
What is apposition of choice with oesophagectomy + enteroectomy?
- End-to-end appositional anastomosis
What part of the GIT heals more poorly and why?
- Oesophagus
- incomplete serosal covering
- poor vascularity
- tension + motion
What suture material should be used with the GIT?
- 1.5-2 metric (up to 3 in stomach)
- Monofilament absorbable (PDS, Maxon, Monocryl)
- Avoid multifilament - wicking, acts as nidus for bacterial growth
What must the sutures incorporate and why?
- Sutures must incorporate the submucosa =
- Strongest layer
- Accurate alignment of submucosa required for adequate healing
What suture pattern should be used and why?
- Appositional patterns (simple interrupted or
continuous) are best - Technically easy and rapid
- Preserve blood supply
- Maintain luminal diameter
- Minimal adhesions
Why is continuous preferred to interrupted?
- Less mucosal eversion
- Less adhesions
- Better submucosal apposition
What suture patterns are used for the oesophagus?
- Single or 2 layer closure
- If 2 layers, deep layer in mucosa / submucosa with knots in lumen and superficial in serosa / muscularis with knots on serosal surface
What suture patterns are used for the stomach?
- 2 layer closure =
- Simple continuous
- Continuous inverting Cushing or Lembert
- Alternatively, 2 layers of Cushing or Lembert
Why would you not use cat gut to stitch GIT?
- Will get digested
If removing a foreign body from the intestines what could you do to reduce likelihood of infection?
- Exteriorise + pack off incision site
- Incise distal to foreign body + squeeze out
- Close incision securely with a monofilament suture
- Check for leakage after closing gut
- Lavage abdomen before closure
- Give prophylactic antibacterials
- Change instruments before abdominal closure
Why would you not do a side to side anastomosis?
- Pouch formation
- Dilation + rupture
How would you perform obliteration of dead space?
- Always suction out all lavage fluid
- Always suture the mesentery if you’ve made a hole in it - otherwise intestines could become herniated in it and lose blood supply
Why is fluid therapy needed?
- GIT surgery often have fluid deficits, electrolyte + acid-base imbalances
- Ongoing losses occur by evaporation from exposed viscera
What can cause secondary peritonitis?
- Chemical
- Septic
Why can peritonitis cause?
- Hypovolaemia
- Metabolic acidosis
- Electrolyte imbalances
- Endotoxic shock
- Death
What are clinical signs of peritonitis?
- Depression
- Anorexia
- Vomiting
- Abdominal pain and distension - “Praying” position
- Ileus
- Pyrexia
- Shock
How is peritonitis diagnosed?
- Radiography
- Haematology - Neutrophilia and left shift, Sometimes degenerative
- Serum biochemistry - Azotaemia, hypoglycaemia
- Abdominal paracentesis - Degenerate neutrophils, Free and/or intracellular bacteria, Compare lactate and glucose to serum
How would you treat peritonitis?
- Fluid therapy
- Broad-spectrum antibacterials - Later based on culture and sensitivity
- Correct primary cause - Exploratory coeliotomy
- Copious peritoneal lavage -Dilution is the solution to pollution!
- Drainage
What is short bowel syndrome? How is it managed + prognosis?
- Occurs after removal of >80% of small intestine
- Medical management
- Prognosis poor
What is ileus? How is it treated?
- Inadequate peristalsis of whole GIT leading to functional obstruction
- Due to vagosympathetic reflex
- Whole gut becomes distended and gas or fluid-filled
- Treat by correction of underlying disease, supportive therapy (fluids, metoclopramide)
What can be done during your daily clinical exam to monitor patients for postoperative peritonitis?
- Check for abdominal pain by palpation - remember cats often don’t show this
- Ballotte the abdomen for fluid thrill
- Weigh them
- Measure their abdominal circumference
What would be your approach to the oesophagus?
- Ventral cervical midline – for oesophagus to level of 2nd rib
- Right intercostal thoracotomy at level of lesion
How would you close a ventral midline coeliotomy?
- Close linea alba
- Single layer of simple continuous
(appositional sutures in external sheath of rectus abdominis) - 5-10mm from edge and 3-12mm apart
What are your approaches to the terminal colon, rectum + anus?
- Ventral approach - Pelvic osteotomy / pubic symphysiotomy
- Anal approach - Evert rectum with stay sutures
- Rectal pull-through approach - Evert, transect, exteriorise, transect, anastomose
- Dorsal “inverted U” approach
- Lateral approach
If you had a patient with a benign distal colonic / proximal rectal mass just inside the cranial end of the pelvis, What surgical approach would you use to access the affected intestine? Why?
- Ventral midline coeliotomy
- benign mass = so only require local excision
- allows full-thickness resection
- can usually retract that section of the intestine cranially and access vis the abdomen
- avoids need to cut pelvis
