Acute Hernia Repair

https://doi.org/10.58974/bjss/azbc006

Hernia repair is a common component of the general surgery curriculum, and with good reason. Surgeons will be aware that acute presentations of hernia account for a significant proportion of emergency work. With challenges in accessing routine care in recent years, it is likely that the rate of acute presentations will increase in the near future¹.

What are the issues

Acute hernia can be a high-morbidity condition. Risk of mortality ranges from 1.7% in older large datasets², 5-6% in modern cohorts^3,4, and up to 11% in a hernia causing small bowel obstruction⁵. These numbers mask some of the heterogeneity in the underlying population. A fit young adult with an incarcerated umbilical hernia containing fat should have a low mortality. The frail, elderly patient with an obstructed or strangulated femoral hernia might not be expected to fare as well⁶.

Delay is bad

It is perhaps unsurprising that delay in access to surgery is associated with worse outcomes. For inpatients, a delay to ‘next day’ vs immediate surgery translates to a 1.5% increase in major complications. Delaying from ‘now’ until ‘after tomorrow’ translates into an 8.3% increase in major complications². In acute abdominal presentation such as obstruction, delay in treatment leads to increased rates of bowel resection, and subsequent increases in mortality⁷. This is true in acute groin hernia, where the odds of death after bowel resection are increased to 3.19 (2.3-4.41)³. Taking into account the bigger picture, limited access to care can convert a low risk elective procedure, into one associated with a 12% bowel resection rate, and prolonged length of hospital stay, and increased resource use¹.

Delay is probably an important aspect of the presentation of obstructed groin hernia in the elderly, where misdiagnosis such as gastroenteritis may delay surgical review. This can translate into a 9.5% mortality rate⁵.

How should a hernia be repaired?

As surgeons, research tends to focus on the technical aspects of repair, including approach and repair materials. In this context, there are three key considerations; perform a safe repair to preserve life and limit morbidity, perform a repair that will avoid recurrence, and perform a repair that will minimise wound morbidity. Essentially, this boils down to a choice between the use of mesh or suture to repair.

Guidelines from the World Society of Emergency Surgery (WSES) suggest that a synthetic mesh can be placed in a clean, or clean contaminated wound (CDC I & II), where there is no evidence of bowel strangulation⁸. These recommendations are largely the same as the HerniaSurg guidance⁹. Much of the evidence to guide this is based on retrospective cohorts with few large randomised trials to inform practice. This is important, as there are some confounders in observational data.

For example, the MASH study found no difference in rates of surgical site infection when comparing suture and mesh repair⁴. It also demonstrated that surgeons were happy to use mesh in most groin hernia repairs in terms of contamination, but were much more conservative in umbilical hernia repair, even where the defect was large. This might suggest that mesh could be used in slightly more contaminated settings than suggested in the guidelines, and in a recent survey of practice¹⁰ . The database study by Sæter et al found that suture repair was associated with increased odds of 30-day mortality (2.39 (1.87–3.04))³. The reason for this is unclear but could be due to patients with more complicated hernias including strangulation, bowel resection, wound contamination having suture repair. In the elective setting, the trial by Kaufmann et al showed that even small umbilical hernia (1-4cm) had lower recurrence rates when mesh was used rather than suture repair¹¹.

In more contaminated settings, the guidelines advocate for the use of a biologic mesh. This may change in light of the recent trial by Rosen et al¹². This explored the rates of recurrence and surgical site complications in elective repair of contaminated hernia, comparing biologic mesh vs synthetic mesh. It found an absolute risk reduction of 15% in hernia recurrence at two years in the synthetic mesh group, and no difference in rates of wound complications requiring intervention. Perhaps it is time to re-evaluate the use of synthetic mesh in the acute setting.

The use of laparoscopy in this setting is at odds with other aspects of practice. Whilst laparoscopy has become the preferred approach for appendicitis¹³, and is used for a range of acute presentations ^14,15, this has not been the case in acute hernia surgery. In fact, the rate may be as low as 3%⁴. This is despite the existence of guidance encouraging the use of laparoscopy⁸, and recent meta-analyses showing the potential safety of this approach¹⁶. Other potential benefits of this include reducing SSI at the hernia site, which may in turn reduce recurrence.

The reason for slow take up of minimally invasive surgery in acute hernia may be multifactorial. Surgeons may wish to avoid making additional defects in an abdominal wall which has already demonstrated hernia, risking further problems. There may also be issues around training. It is thought that the learning curve may pose a challenge, although this may be mitigated by a generally high level of laparoscopic skills¹⁷. It may also be linked to exposure and volume of experience in repairs. A survey of UK practice found that in the acute setting, a laparoscopic repair of an umbilical hernia was preferred by 8% of specialist hernia surgeons, but only 4% of general surgeons. Similarly, 22% and 7% respectively would offer laparoscopic management of acute groin hernia presentations¹⁰. Thus, even experienced hernia surgeons prefer open surgery for incarcerated hernia repair. This also poses a further question for the delivery of acute hernia care; outcomes for emergency laparotomy have been shown to differ according to specialty of the treating surgeon¹⁸. Does this implication extend to emergency hernia surgery, and if so, is there a role for an acute hernia specialty on call?

Finally, it is difficult to ignore the rise of the robot as a minimally invasive platform. There is potentially no major difference in outcomes between robot and laparoscopic repair in the elective setting^19,20. However, the improved ergonomics of a robotic platform may facilitate easier minimally invasive repair of hernia. Institutions have already reported favourable outcomes of the robotic approach in the emergency setting²¹. As robotic platforms and associated skill-sets become more widespread, standard approaches to acute hernia may change.

Longer term follow-up

As with many studies focused on acute events, follow-up tends to terminate within 30 or 90 days. For outcome measures such as recurrence, the follow-up period may need to be measured in years for accurate measurement²². Linked to this is the need for longer term data on outcomes such as quality of life and function after emergency hernia repair.  Available studies include relatively small numbers with follow-up for at least 2 years and report complications, but no patient reported data^23,24. As recurrence and quality of life are two important outcomes, it is frustrating that these are not better reported.

The frail patient

There may be some uncertainty around the management of the frail patient, particularly when they may have previously declined, or been declined, an elective hernia repair. When attending hospital with an acutely symptomatic hernia they are likely to be below their physiological baseline. The first consideration is whether they should be offered a repair in what is now a high risk situation. Recent data suggests that the majority of people would be offered a repair in this situation⁴. This may require the procedure to be performed under local or regional anaesthesia, and the associated challenges of reducing a viscus to a cavity under pressure and repeated intrusion of bowel back into the surgical site.

Summary

The current knowledge base can inform practice with varying degrees of certainty. It is clear that acute hernia presentations are common, and can lead to death in up to 1 in 20 cases. There is no real consensus on the ‘best’ repair, with advocates of different techniques and approaches providing reasonable grounding for each. At present, treatment should be tailored to the patient and the type of hernia, with the choice of suture or mesh, open or laparoscopic repair defined by the skills of the surgeon, and the need to avoid harm to the patient. This is clearly an area ripe for future research.