Open abdomen

Laparostomy = leaving the abdomen open.

Phases:

Sabiston divides it into 5 phases:

1. Initial laparotomy and use of temporary closure device
2. ICU resuscitation
3. First re-operation
4. Management of open abdomen
5. Planned ventral hernia

Phase 1: Initial laparotomy and use of temporary closure device

• Indications for temporary abdominal closure (open abdomen)
  • Patients with/at risk of IAH/compartment syndrome
  • Damage control
    • Severe haemorrhage
    • Hypothermia, acidosis, coagulopathy
    • Delayed definitive operation secondary to patient's physiologic state
  • Major abdominal and/or retroperitoneal tissue oedema
  • Questionable visceral viability
  • Planned acute re-operation
  • Severe intra-abdominal sepsis
  • Triage
• Goals:
  • Minimise damage to abdominal contents
  • Minimise adherence of abdominal contents to anterior abdominal wall
  • Retain the ability to close the fascia primarily at a subsequent operation (aim to close within 8 days - much higher rate of complications after this point)
• Techniques:
  • Skin closure techniques
    • Simple running sutures
    • Sequential towel clip closure
    • Silo technique/Bogota bag
      • Suture an inert, non-permeable barrier (IV bag etc) to the skin or fascia
      • Prone to leakage/evisceration
      • Do not prevent retraction
      • Do not allow effective removal of abdominal fluid
      • Rates of primary closure are mostly <30%
  • Fascial closure techniques
    • Vicryl/biological mesh, polypropylene mesh, Wittman Patch, Esmark bandages, expanded PTFE
    • Should initially be loose to allow for visceral swelling without ACS
    • Do not prevent adhesions to anterior abdominal wall
    • For non-absorbable meshes, fistula formation is very high (6-18%) if a non-adherent barrier is not placed under the mesh (omentum, Ioban sheet)
    • Sequentially tightened by excising the central part and resuturing the fascial material closed
    • Should typically be tightened every 24-48 hours until the fascia is 2-4cm apart, at which point the fascia is closed primarily
    • Most useful when an extended duration of laparostomy is predicted (unlikely to be closed by 8 days)
  • Negative pressure applications
    • ABThera - inner plastic-encased sponge designed to be indirect contact with the viscera, followed by a macroporous foam sponge, followed by adhesive dressing
      • Tips for ABThera
        • Maximally lateralise the internal visceral layer - prevents bowel from slipping out, and prevents adhesions. Some suggest taking down falciform ligament to help get it right into paracolic gutters.
        • Bury any intestinal anastomoses deep in abdominal cavity
        • Test thoroughly for leaks (can use tincture of benzoin)
        • Can use staples to fix sponge to skin edges (need it flush, as any contact of skin to sponge can damage epidermis, but you also want full coverage of wound)
        • Ostomy appliances should be OVER the adhesive layer, not under, or you risk sucking poo into the wound
        • Get the hole sized right - many manufacturers suggest 2x2cm
        • Adjust suction level as needed - 125mmHg is optimal for wound healing, but put down to 75mmHg if there is bleeding/coagulopathy
    • Low rate of fistulas (but beware of anastomoses directly under the pack and intra-abdominal sepsis), average primary closure rate of 67%
    • Highest primary fascial closure rates when the VAC is used in conjunction with a fascial tension device (such as simple interrupted fascial sutures which are added/tightened each relook)
• Choice of initial technique
  • My approach:
    • Definitely one relook: Abthera/VAC
    • Going to need multiple relooks: Large polypropylene mesh, with Ioban on each side, then VAC over the top
  • Consensus guidelines recommend NPWT techniques initially, during the resuscitative phase where risk of ACS is highest
  • NPWT is especially favoured in inflammatory pathologies - highest delayed primary closure rate, lowest mortality, lowest ECF formation

Phase 2: ICU resuscitation

• Management in ICU with the open abdomen
  • Nutrition - Sabiston says early enteral nutrition in the open abdomen is beneficial, if feasible
  • No specific antibiotic prophylaxis - data says unnecessary
  • Strict fluid balance aiming euvolaemia
  • Can be extubated between washouts if co-operative
  • Correct hypothermia, coagulopathy and acidosis
  • Minimising crystalloid infusion has been shown to increase rates of primary fascial closure
  • Routine monitoring of intra-abdominal pressures in those with large-volume resuscitation due to haemodynamic instability or ongoing bleeding
    • See separate topic, but essentially, if bladder pressure >20mmHg, monitor hourly, and if any sign of end-organ dysfunction, needs return to theatre

Phase 3: First re-operation

• Takebacks
  • Washout and re-VAC every 1-3 days
  • Only do it at the bedside if patient is unstable and can't go to OT
  • Check for complications/problems that will delay closure and serial fascial tightening
  • For first 24-72 hours after index operation, adhesions are soft and give way easily. Operating again between 1-4 weeks can be hazardous. Avoid using sharp dissection. Generally look for collections at the periphery, and try to leave the 'central visceral block' alone.
• Check for reasons to delay closure:
  • Ongoing inflammatory response
  • Visceral oedema
  • Retraction of abdominal wall musculature
  • Lack of source control
  • Intra-abdominal abscess
  • Enterocutaneous fistula
• Assess readiness for closure:
  • Direct closure is usually possible when the fascial edges are 3-7cm apart
  • Intra-abdominal pressure >20mmHg or a rise of peak inspiratory pressure of 10cm H2O during attempts to close fascia are warning signs
  • Delayed fascial closure (phase 4) might be prudent in this group
• Choice of technique to close after relook laparotomy:
  • Patients predicted to be uncomplicated and likely to close within 8 days: NPWT + sequential fascial closure
  • Patients with risk factors for difficult abdomen: NPWT + serial fascial tightening
    • Direct serial suturing if feasible
    • Interposition polypropylene mesh protected by Ioban if abdomen is too tight for direct suturing

Phase 4: Management of open abdomen

• Techniques for definitively closing the difficult open abdomen
  • Serial fascial suturing in combination with NPWT
  • Gradual fascial tightening via trans-fascial tension-bearing closure techniques
    • Principle is to redistribute tension lateral to rectus sheath, theoretically lengthening lateral wall musculature
    • Techniques
      • Wittman Patch (artificial burr)
      • Transabdominal wall traction (TAWT)
      • Mesh-mediated fascial traction
        • Protect viscera with a polyethylene sheet or double-sided Ioban
        • Suture in an oval-shaped inlay polypropylene mesh
        • Apply VAC over the top (Abthera)
        • Takeback every 2-3 days: exchange the protective sheet, and serially tighten the mesh, until it can be removed
  • Biosynthetic mesh - avoid in acute setting due to risk of infection
    • Options - human acellular dermal matrix (HADM), absorbable mesh like Vicryl, composite meshes
    • Techniques - two options
      • Underlay - if skin is lax enough to close but fascia not, you can place the mesh as underlay and directly close the skin. The mesh would typically be placed intra-peritoneal and secured with transfascial sutures.
      • STSG - if neither skin nor fascia can close, the mesh is placed underlay intra-peritoneal with standard saline moist to dry dressings BD for 2-4 weeks until satisfactory granulation has appeared in the wound bed. Then STSG can be placed. Will then need definitive component separation and delayed closure in 6-9 months. See bottom of page for a description of how to definitively close this type of abdomen.
  • Component separation - full component separation is not recommended in acute setting - makes future hernia repairs much harder
• Pharmacologic adjuncts
  • Continuous neuromuscular blockade doesn't make a difference
  • Botox injection has been shown to help in both elective and acute setting

Phase 5: Planned ventral hernia

• If closure has not occurred by 8-14 days, it is unlikely to be achievable in the acute setting (although plenty of closures have been reported up to 20-40 days)
• Options:
  • If able to close skin: skin closure with absorbable mesh inlay or biologic mesh over drains
  • If unable to close skin: intra-peritoneal vicryl mesh, with STSG on top once granulation tissue appears
  • If persisting infection/dirty wound: biologic bridge repair with overlay NPWT
• Then aim for future ventral hernia repair when everything else is optimised

Complications of open abdomen

• Entero-atmospheric fistula - will likely need operative repair
  • No perfect solution to controlling the fistula in the acute setting of open abdomen - be creative using drain tubes etc