What Causes Hernias to Occur and Reoccur?
Non-Patient Factors that Increase the Risks and Why
Surgeon Experience
Our Consultant Surgeon is highly experienced, and Hernia Clinic Hampshire has the highest volume hernia surgeon in the area, having repaired around 2,000 hernias!
Surgeon and clinic volumes influence the risk of recurrence. This means that the more cases a surgeon or clinic has, the more experience they have and thus lower their recurrence rates.
According to the Danish national hernia databases review a high-volume surgeon / clinic is defined as >25 repairs performed a year.
The Hernia
Risk of recurrence can be influenced by the hernia itself- it’s size, placement, and if it has already been repaired before.
Patient Factors that Increase the Risks and Why
Below are different factors that make a hernia more likely to recur and that patients can help themselves with. Some risk factors can be removed or significantly lowered, while some cannot.
Smoking: Smoking changes the structure of connective tissue. Weak connective tissue leads to hernia formation.
Being overweight: The lower abdomen provides support to the abdominal contents. The more fatty tissue there is in the abdomen, the more support is needed, so hernias are more common in obese patients. Having a BMI of greater than 25 increases the risk of hernias occurring. This heightened risk of hernia formation increases exponentially as BMI increases. We do not routinely offer surgery for patients with BMI greater than 33.
Increased age and frailty: Ageing changes the structure of connective tissue. Natural wear and tear can make these canals/natural anatomical weaknesses bigger, so hernias are more likely to occur as we get older. We can still perform successful hernia surgery at any age. A persons age is not the limiting factor. Surgery can be appropriate in any age if patients strength and mobility allows them to follow a personalised treatment and recovery plan. Maintaining strength through exercise and training will reduce the rate of connective tissue deterioration and help with post operative recovery.
Poorly controlled diabetes: Poor glucose control over time alters the rate at which we replace tissue, making it ‘age’ quicker.
Chronic lung disease such as asthma and COPD: Poorly controlled respiratory disease can cause abdominal muscles to tire more quickly and can exert increased pressure on the weak areas of the abdominal wall.
Certain medications such as steroids and immunotherapy: Steroids reduce the amount of collagen we replace as our tissues are recycled. Some drugs can alter the structure of connective tissue.
These risks for hernia formation (including recurrence) work by deteriorating connective tissue quality and or increasing the forces applied to the abdominal wall.
To understand this, you need to understand the structure of collagen. Collagen is a structural protein that lies in parallel fibres. These parallel fibres could be forced apart by pressure applied to them. So, they have evolved (di-sulphide) cross-linking bridges that prevent the parallel fibres being forced apart and another protein woven into the parallel fibres called elastin that allows the collagen to stretch and recoil with pressure and movement. The mix of genes we have for expressing this individualizes the expression of our connective tissues so without additional risk factors we have a varying risk of abdominal wall hernias forming just from how our genes are expressed.
These risks for hernia formation (including recurrence) work by deteriorating connective tissue quality and or increasing the forces applied to the abdominal wall.
To understand this, you need to understand the structure of collagen. Collagen is a structural protein that lies in parallel fibres. These parallel fibres could be forced apart by pressure applied to them. So, they have evolved (di-sulphide) cross-linking bridges that prevent the parallel fibres being forced apart and another protein woven into the parallel fibres called elastin that allows the collagen to stretch and recoil with pressure and movement. The mix of genes we have for expressing this individualizes the expression of our connective tissues so without additional risk factors we have a varying risk of abdominal wall hernias forming just from how our genes are expressed.
Some external risks alter this: Smoking, older age and steroids weaken our connective tissues.
Smoking reduces the amount of collagen we have in tissues (makes tissues thinner), with a lower proportion of elastin and far fewer di-sulphide bridges (so they are weaker) making it easier to push collagen fibres apart.
Old age sees the same effect in slightly different proportions. So, as we age, we become more prone to hernias.
Steroids reduce the amount of collagen we replace as our tissues are recycled.
Poorly controlled respiratory disease and obesity work in the other way.
By increasing the pressure/force applied to our abdominal wall. Whether you are more prone to developing an apple rather than a pear shape alters the mechanism, but the outcome is the same. Excess fat deposition occurs in and between all tissues this alone can weaken the connective tissue so increases the risk described above without altering the relative proportions of the structural proteins. Fatty tissue dilutes them a little if you like and fat has no strength.
Apple shapes deposit fatty tissue inside their abdomen and this accumulating mass exerts increasing pressure against the abdominal wall. As this is countered by core muscle contraction with simple everyday activity such as walking or getting up and out of a bed or chair these muscles pull against the more fixed natural weak areas that can open up potential shapes to become actual spaces. The greater your intra-abdominal pressure the greater this effect.
The more obese someone is the more effort is required to lift that weight during breathing so muscles tire quicker and the fixed natural weak areas of the abdominal wall get pulled allowing the intra-abdominal content to exert more pressure or force against the weakest areas. This is how pear shapes develop hernias. The more overweight we are the more we combine apple and pear shapes and so make these effects even greater.
Respiratory disease affects our risk as the top half of our abdominal wall is needed to aid respiration.
It is why using your arms to brace yourself when short of breath helps your breathing. You are using your abdominal wall and shoulders to aid respiration. The more easily we become short of breath (poorly controlled respiratory disease) the more effort is required to lift that weight during breathing. As described above, this causes muscles to tire more quickly and the fixed natural weak areas of the abdominal wall to get pulled, allowing the intra-abdominal content to exert more pressure or force against the weakest areas. The additional work of breathing needed in poorly controlled respiratory disease (and obesity) puts more tension on a hernia repair increasing the risk of recurrence in the first 6-12 months
How diabetic control alter the risk.
This is more complex to explain. To keep it simple: poor glucose control over time alters the rate at which we replace tissue, making it ‘age’ quicker. Poor glucose control increases the risk of wound complications after hernia repair such as wound infection. These wound complications have been shown to increase the risk of recurrence. The more normal our average blood sugars the less this happens. For this reason the national guidelines state that elective surgery such as hernia repair should not be offered until the HbA1c is less than 69.
Some risks for recurrence can be eliminated, while some can be only be modified.
Smoking and obesity can both be stopped. It is important before hernia surgery to get to a BMI less than 33 and have ceased smoking tobacco for 6 months prior to surgery.
Other risks can only be modified, such as better-controlled respiratory disease or diabetes. You cannot stop yourself from ageing, but maintaining strength through exercise and training will reduce the rate of connective tissue deterioration and help with post operative recovery.
You can only repair each hernias 2-3 times. It is important to give each attempt the best chance of success. At Hernia Clinic Hampshire this philosophy is key to the advice we offer and the reason we give this advice.
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