Surgery of the abdominal cavity

Question 1

Anatomy of the abdominal wall

Answer 1

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

Question 2

Anatomy of the peritoneum

Answer 2

Double layer (visceral and parietal peritoneum) with huge potential space in between (150% greater than total surface area of skin!)

Question 3

Anatomy of the greater omentum

Answer 3

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

Question 4

Bursal portion of the greater omentum

Answer 4

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

Question 5

Splenic portion of the greater omentum

Answer 5

forms gastrosplenic ligament

Question 6

Veil portion of the greater omentum

Answer 6

contains the left limb of the pancreas.

This can be visualised by reflecting the greater omentum dorsally over the stomach.

Question 7

Functions of the greater omentum

Answer 7

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

Question 8

Anatomy of the lesser omentum

Answer 8

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

Question 9

Coeliotomy

Answer 9

refers to any incision made into the abdominal cavity.

Question 10

Laparotomy

Answer 10

by strict definition refers to a flank incision into the abdominal cavity. Tends to be used interchangeably with coeliotomy

Question 11

Approach to ventral midline coeliotomy

Answer 11

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

Question 12

What size blade do you use for coeliotomy?

Answer 12

10

Question 13

What scissors are used to cut along the midline

Answer 13

Mayo scissors

Question 14

Where does the falciform fat lie?

Answer 14

Ventral midline of the cranial abdomen

Question 15

Which retractors can be used to improve exposure in the abdomen

Answer 15

Balfour or Gosset retractors

Ribbon malleable retractors

Question 16

Abdominal exploration

Answer 16

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).

Question 17

What is the duodenal manouvre?

Answer 17

use mesoduodenum to retract abdominal contents to allow visualisation of right paravertebral gutter (right kidney, right ovary in females, right adrenal)

Question 18

What is the pringle manouvre?

Answer 18

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

Question 19

What is the colonic manouvre

Answer 19

Use mesocolon to retract abdominal contents to allow visualisation of left paravertebral gutter (left kidney, left ovary in females, left adrenal)

Question 20

Peripheral liver biopsy

Answer 20

Crushing method

Suture fracture

Question 21

Central liver biopsy

Answer 21

Punch biopsy

Question 22

Pancreatic biopsy

Answer 22

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

Question 23

Intestinal biopsy

Answer 23

(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

Question 24

Closing a coeliotomy

Answer 24

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

Question 25

Which layers of rectus abdominus must be sutured in coeliotomy closure?

Answer 25

External leaf of the rectus abdominus

Question 26

Suture placement when closing muscle layer of abdomen

Answer 26

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.

Question 27

Complications of exploratory coeliotomy

Answer 27

Dehiscence

Post operative infection

Seroma

Question 28

Causes of dehiscence

Answer 28

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

Question 29

Possible sequelae of dehiscence

Answer 29

Incisional hernia

Evisceration of abdominal organs

Question 30

Laparotomy

Answer 30

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)

Question 31

Indications for laparotomy

Answer 31

Flank ovariohysterectomy, especially cats

Adrenalectomy

Gastrostomy tube placement

Cystostomy tube placement

Question 32

Laparoscopy

Answer 32

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

Question 33

Indications for laparoscopy

Answer 33

Biopsy of abdominal organs

Laparoscopic surgery
§ Ovariectomy/ovariohysterectomy
§ Gastropexy
§ Feeding tube placement (jejunostomy/gastrostomy)
§ Intestinal foreign body removal / intestinal biopsies
§ Cystotomy
§ Adrenalectomy
§ Cholecystectomy