An overview of the process
A large prosthetic mesh is placed in the retromuscular plane behind the rectus muscles and in front of the posterior rectus sheath, with wide overlap beyond the defect. Where the defect is too wide to close, a transversus abdominis release or anterior component separation is added.
In a large long-standing hernia the viscera have lost domain. Returning them and closing the abdominal wall raises intra-abdominal pressure, which reduces diaphragmatic excursion and lung compliance, reduces venous return and cardiac output, and reduces renal and splanchnic perfusion. A steep rise in peak airway pressure as the fascia is approximated is the first sign, and it determines whether the patient can be extubated.
Pre-op assessment
- Respiratory reserve predicts a difficult extubation. Document smoking history, COPD, obesity and sleep apnoea.
- Obesity is common in this population and drives both recurrence and wound complications. Where BMI is high, the bariatric guideline applies to airway management and drug dosing.
- Establish the number of previous laparotomies and what occurred at them.
- Cardiac reserve. The operation is long with significant fluid shifts.
- Smoking cessation and weight optimisation change outcome and require weeks. Establish whether prehabilitation has been offered.
- Diabetes and glycaemic control affect wound and mesh infection risk.
- Consent covers general anaesthesia, thoracic epidural or abdominal wall blocks, a prolonged operation, significant postoperative pain, drains, possible critical care, and the possibility of remaining intubated at the end of surgery.
Induction and intra-operative management
- Volatile or TIVA, with tracheal intubation.
- Deep neuromuscular blockade is a surgical requirement, not a preference. The surgeon is working in a muscular plane and attempting to bring the fascia together; any tone works directly against this, and inadequate relaxation at closure risks a repair under excessive tension. Monitor objectively and maintain until the fascia is closed.
- An arterial line is required for a major reconstruction.
- Large-bore peripheral cannulae.
- Core temperature monitoring, neuromuscular monitoring, urinary catheter.
- Active warming with forced-air warming and a fluid warmer. A large surface area is exposed for a prolonged period.
- Single-dose antibiotic prophylaxis within 60 minutes of incision, redosed if prolonged. Mesh is implanted and timing matters.
- Mechanical thromboprophylaxis should be used if not contraindicated. Venous thromboembolic risk is high — obesity, a long operation and reduced mobility.
- Adhesiolysis is often extensive and slow. Enterotomy changes the operation and the choice of mesh.
Fluid management
- Goal-directed fluid therapy. The operation involves a large raw surface with significant evaporative and third-space loss, but a liberal strategy is not appropriate.
- Oedematous bowel is harder to return to the abdomen, which makes the closure tighter and the extubation less likely.
Closure and intra-abdominal pressure
- As the fascia is approximated, watch peak and plateau airway pressure and compliance, and watch the arterial pressure and cardiac output.
- Where airway pressures rise steeply, tell the surgeon the number. A bridged repair, further release or staged closure may be chosen.
- Confirm that neuromuscular blockade is still deep at the point of closure.
Perioperative analgesia
- The repair is under tension across the whole abdominal wall and the operation is extremely painful.
- Thoracic epidural is an established choice.
- Abdominal wall blocks are an alternative or adjunct. The retromuscular dissection disrupts the planes on which a transversus abdominis plane or rectus sheath block depends, and the surgeon may be able to place catheters in the retromuscular space under direct vision. Agree at the team brief who is placing what.
- Regular paracetamol.
- NSAIDs. The default is cautious use rather than avoidance. They may be used where renal function is adequate, the patient is euvolaemic and there is no specific contraindication.
- PONV prophylaxis with at least two agents. Vomiting strains a fresh repair.
- For prophylactic low molecular weight heparin, allow 12 hours from the last dose before siting or removing an epidural catheter and 4 hours afterwards; for treatment dose, 24 hours and 4 hours. Extend the interval if insertion was traumatic.
Post-operative care
- Extubation is not automatic. Decide with the consultant on the basis of the airway pressures achieved after closure, respiratory reserve, temperature, analgesia and fluid balance.
- Consider level 2 care for a large reconstruction, component separation, significant comorbidity or a tight closure.
- Handover should include the extent of the repair and whether component separation was performed, the peak airway pressure before and after closure, whether an enterotomy occurred, the drains, the epidural or block details, the last dose of low molecular weight heparin and when the next is due, and the fluid balance.
- Abdominal compartment syndrome is the complication this operation specifically creates. Rising airway pressures with oliguria, a rising lactate, a distended tense abdomen and cardiovascular compromise. Treat rising airway pressure with oliguria as compartment syndrome until disproven.
- Respiratory failure from splinting, atelectasis and inadequate analgesia is the commonest reason for deterioration.
- Other complications to anticipate are bleeding into the large raw retromuscular surface, missed bowel injury, surgical site infection with mesh in situ, and ileus.
References
- Association of Anaesthetists of Great Britain & Ireland, Obstetric Anaesthetists' Association, Regional Anaesthesia UK. Regional anaesthesia and patients with abnormalities of coagulation.
- Kietaibl S, Ferrandis R, Godier A, et al. Regional anaesthesia in patients on antithrombotic drugs: Joint ESAIC/ESRA guidelines. European Journal of Anaesthesiology, 2022;39:100–132.