Definitions

Necrotising pancreatitis
- Acute necrotic collection (ANC)
  - Fluid collection with solid necrotic component within 4 weeks.
- Walled-off necrosis (WON) – > 4 weeks.
  - CT – well defined, mature, enhancing wall, containing fluid and solid necrotic material.

Evolution of pancreatic necrosis/collections:

True pancreatic necrosis – minimal separation of devitalised tissue
Transitional pancreatic necrosis – partial but incomplete separation
Walled-off necrosis (WON) – good separation of devitalised tissue within fluid-filled cavity and formation of fibrous wall lined with granulation tissue
Pseudocyst – almost complete resolution of solid component, well formed fibrous wall lined with granulation tissue

Management principles

Not-infected
- Observe
  - May take >12 weeks
- May require intervention for symptoms but treatment should be delayed till after 4 weeks
Infected
- Diagnosis
  - Suspect in clinical deterioration
  - CT shows gas
  - Uncertainty consider FNA and gram stain
- Treatment
  - Broad spectrum antibiotics
  - If unresolving sepsis then may require intervention
    - Minimally invasive techniques
      - Percutaneous, endoscopic and laparoscopic drainage
      - Step-up strategy

‘Step up’ approach

Percutaneous drainage (PCD)
- PANTER trial - 35% successfully managed with small-bore (4mm) drain) A Step-up Approach or Open Necrosectomy for Necrotizing Pancreatitis, page 1
- If this fails then up size the drain sequentially
Minimally invasive surgery
- Sequential drain tract dilatation allowing insertion of large bore 30Fr double lumen lavage system is useful step-up approach
- Video-assisted retroperitoneal debridement (VARD). Small 5-cm incision left flank. Used if PCD fails. Useful for retroperitoneal/retrocolic collections.
The PANTER study (ΡΑոсrеatitiѕ, Necrosectomy versus sTEp up appRoach)
- Randomized trial of percutaneous catheter drainage in 88 patients,
- 35% treated successfully with percutaneous catheter drainage alone,
- Remainder required percutaneous drainage followed by VARD
- Compared with open pancreatic dеbridemеnt
  - Significantly decreased the rate of new-onset multiple organ failure (12 versus 40 percent), incisional hernias (7 versus 24 percent), and new-onset diabetes (16 versus 38 percent) but did not significantly affect mortality.

Endoscopic Cystgastrostomy
- Lumen-opposing stents (Hot AXIOS) allow rapid decompression of WON, often treatment of choice.
- Stent from stomach to WON
Endoscopic necrosectomy
- Then able to be performed endoscopically via the AXIOS stent.
Morbidity with recurrent sepsis, haemorrhage and stent migration.

Last line
May be appropriate in fit patients with no organ compromise and organised collection, allowing rapid recovery and avoid repeated interventions associated with minimally invasive procedures.
Often focused on drainage of collection identified on CT
Can be laparoscopic or open
Cystgastrostomy
- Anterior approach
  - Liver retracted
  - Stomach is opened anteriorly
  - Intraoperative USS to verify the location of the cyst or aspirate
  - Ligasure used to incise the posterior wall of the stomach and enter the pseudocyst.
  - Cavity is washed out and solid debris is removed.
  - Cyst is anastomosed to the stomach.
  - Anterior wall is closed.
- Posterior approach
  - Lesser sac is entered
  - Pseudocyst entered
  - Incise into the posterior wall of the stomach
  - Linear stapler to create cyst-gastrostomy
  - Common defect closed with running sutures.
- Other option is cyst-jejunostomy.
Necrosectomy
- Ideally performed via the cystgastrostomy as this then leaves an internal route for continued drainage
- If this is not possible due to location of the collection then the collection can still be drained and necrosectomy performed and a surgical drain left in place