Surgery of the abdominal cavity Flashcards
Anatomy of the abdominal wall
External abdominal oblique muscle – fibres run caudoventrally
Internal abdominal oblique muscle – fibres run cranioventrally
Transversus abdominis muscle – fibres run dorsoventrally
Rectus abdominis muscle – runs lateral to the ventral midline from cranial to caudal
Linea alba (ventral midline) – composed of the aponeuroses of the above muscles – this is thickest at the umbilicus and thinnest caudally
Anatomy of the peritoneum
Double layer (visceral and parietal peritoneum) with huge potential space in between (150% greater than total surface area of skin!)
Anatomy of the greater omentum
Double peritoneal sheet with superficial ventral and deeper dorsal layer
Omental bursa is the potential space in-between these layers
Three portions
○ Bursal portion
○ Splenic portion
○ Veil portion
Bursal portion of the greater omentum
Largest.
Opening is epiploic foramen.
Bleeding from liver can be arrested by performing Pringle manoeuvre - finger is placed cranial to pylorus into epiploic foramen then curled ventrally to occlude portal vein and hepatic artery
Splenic portion of the greater omentum
forms gastrosplenic ligament
Veil portion of the greater omentum
contains the left limb of the pancreas.
This can be visualised by reflecting the greater omentum dorsally over the stomach.
Functions of the greater omentum
Immune function: milky spots: aggregations of neutrophils, macrophages and lymphocytes
Blood supply
Sealing leaks: tends to migrate to areas of inflammation (abdominal policeman). Very useful for improving integrity of closure of hollow organs and preventing leakage via omentopexy or simple wrapping.
Stimulus for healing
Angiogenic factors – improves blood supply/healing
Lymphatic drainage
Anatomy of the lesser omentum
Lies between the lesser curvature of the stomach and the porta hepatis (where the portal vein and hepatic artery enter the liver)
Continuous with the mesoduodenum
Coeliotomy
refers to any incision made into the abdominal cavity.
Laparotomy
by strict definition refers to a flank incision into the abdominal cavity. Tends to be used interchangeably with coeliotomy
Approach to ventral midline coeliotomy
Clip and prepare skin
Number 10 scalpel blade
Haemostasis using diathermy, haemostats, or ligation
Avoid undermining sc fat around linea alba as it aids healing
Stab incision through linear alba and then mayo scissors to extend
Remove the falciform fat to increase exposure in cranial abdomen
Use moistened laparotomy swabs to protect the abdominal walls
Improve exposure using retractors, retracting abdominal contents, or assistant
What size blade do you use for coeliotomy?
10
What scissors are used to cut along the midline
Mayo scissors
Where does the falciform fat lie?
Ventral midline of the cranial abdomen
Which retractors can be used to improve exposure in the abdomen
Balfour or Gosset retractors
Ribbon malleable retractors
Abdominal exploration
Thorough and systemic approach
Palpate/examine each liver lobe
Examine the stomach
Duodenum, right limb of pancreas, duodenocolic ligament
Duodenal manouvre
Colonic manouvre
Follow colon up to the caecum, ileocaecocolic junction then ileum, jejunum, duodenum up to duodenocolic ligament.
Mesenteric lymph nodes, spleen, left limb of pancreas, bladder, rectum. Palpate sublumbar lymph nodes (chain along aorta on midline).
What is the duodenal manouvre?
use mesoduodenum to retract abdominal contents to allow visualisation of right paravertebral gutter (right kidney, right ovary in females, right adrenal)
What is the pringle manouvre?
Bleeding from liver can be arrested by performing Pringle manoeuvre - finger is placed cranial to pylorus into epiploic foramen then curled ventrally to occlude portal vein and hepatic artery
What is the colonic manouvre
Use mesocolon to retract abdominal contents to allow visualisation of left paravertebral gutter (left kidney, left ovary in females, left adrenal)
Peripheral liver biopsy
Crushing method
Suture fracture
Central liver biopsy
Punch biopsy
Pancreatic biopsy
Suture fracture
□ Mesentery incised
□ Encircling ligature placed around area to be biopsied
□ Biopsy excised carefully with no. 11 scalpel blade
Vessel sealing device
Histopathology only
Intestinal biopsy
(Stomach), duodenum, jejunum + ileum
Different techniques
□ Scalpel + scissors
□ Scalpel only
□ Biopsy punch (6mm dog, 4mm cat)
Debakeys or suture essential for holding tissue
MUST get all layers
Suturing
□ Scalpel methods generally sutured longitudinally
□ Punch biopsy method sutured transversely
Place biopsies on suture card to maintain orientation
Closing a coeliotomy
Lavage
- local if minimal/contained contamination
- generalised otherwise
Glove/instrument change
- if contaminated
- if neoplasia
Use PDS or polyglyconate to close
No need to include peritoneum - increases risk of adhesions
Muscle layer closed with simple continuous, as is sub cut layer
Intraderms to appose skin edge and reduce tension
Additionally closed with non-absorbable suture (cruciate or simple interrupted) or staples if underlying disease or older patients
Which layers of rectus abdominus must be sutured in coeliotomy closure?
External leaf of the rectus abdominus
Suture placement when closing muscle layer of abdomen
5-10 mm from the incised edge of the linea alba
3-12 mm apart depending on body size is recommended.
Both simple interrupted and simple continuous suture patterns are acceptable.
Simple continuous patterns are now favoured by most surgeons as tension is distributed evenly and bursting pressure is equivalent to simple interrupted closures.
This pattern is also more watertight and therefore fluid is less likely to leak out from the abdominal cavity through the incision.
For additional knot security 1 extra throw is added to the knot at the start and 2/3 to the knot at the end (this knot uses a loop of suture and is thus is asymmetrical) of a simple continuous suture line ie.
PDS would have five knots at the beginning of the incision and six/seven knots at the end.
Complications of exploratory coeliotomy (post surgery)
Dehiscence
Post operative infection
Seroma
Causes of dehiscence
Technical errors (most common cause) e.g. rectus sheath not engaged, sutures spaced too widely
Infection/seroma – predisposes to wound breakdown
Excessive patient activity (lead walking only for 2 weeks, no running, jumping or climbing stairs
Concurrent therapy: corticosteroids.
Concurrent diseases: hyperadrenocorticism, hypoalbuminaemia, obesity
Possible sequelae of dehiscence
Incisional hernia
Evisceration of abdominal organs
Laparotomy
Flank approach
Improved access to dorsally located organs e.g. kidneys, adrenals, uterus, ovaries
Can’t explore whole abdomen - big disadvantage
Grid approach through muscles (external abdominal oblique, internal abdominal oblique and transversus abdominus split in the direction of their fibres)
Indications for laparotomy
Flank ovariohysterectomy, especially cats
Adrenalectomy
Gastrostomy tube placement
Cystostomy tube placement
Laparoscopy
Heavily favoured in human surgery to allow more rapid recovery/decreased morbidity.
Allows excellent visualisation via a minimally invasive approach
Steep learning curve – initially surgical times are a lot longer
Trocars placed for telescope/instruments.
Carbon dioxide used for insufflation: improves visualisation, compromises ventilation; positive pressure ventilation required
Indications for laparoscopy
Biopsy of abdominal organs
Laparoscopic surgery
§ Ovariectomy/ovariohysterectomy
§ Gastropexy
§ Feeding tube placement (jejunostomy/gastrostomy)
§ Intestinal foreign body removal / intestinal biopsies
§ Cystotomy
§ Adrenalectomy
§ Cholecystectomy
