The use of mesh in hernia repair, risk management and the advantages of day surgery

The severity of symptoms or the possibility of strangulation must be balanced against the risk of the anaesthetic, the operative or post-operative complications and the long term success of surgical repair.

Teaching about herniae has not altered substantially for many years. The pre-clinical student studies the anatomy of the abdominal wall, inguinal canal, femoral canal and scrotum in great detail. The Clinical student is taught to apply this, together with the history and demonstration of physical signs to arrive at a precise diagnosis.

The residency staff are required to understand the pre-operative and post-operative care.

The primary care physician should do all this and be able to counsel a patient – patients wish to know the different possibilities. The primary care physician is also usually responsible for the initial assessment of the degree of urgency, referral for surgical assessment and the decision regarding where and by whom the surgery should be performed.

CURRENT SITUATION REGARDING HERNIAE
Herniae have been a surgical problem since time immemorial. Many of the great names of surgery are attached to advances made in the anatomical understanding and surgical repair.  However the results of hernia surgery in the past were not always good.

Now the results of surgical correction have improved with both the morbidity and mortality from surgery falling substantially. Most hernias can be repaired under local anesthesia.  Patients spend only a few hours in hospital. The cost savings of this are enormous and allow resources to be diverted to other problems.  A variety of surgical techniques have evolved and all are designed to provide a short stay in hospital, rapid mobilization and early return to work, whilst at the same time claiming there is minimal pain.   

The recurrence rate is said to be less.  However all surgeons can attest that they see other surgeons’ recurrence as well as their own.

Many series now quote recurrence rates of 0.1 – 0.5 %, these usually come from centers of specialists, primarily devoted to the care of hernias.  These are very impressive figures. One problem however, in assessing these series is in judging the extent of follow-up undertaken.

      How accurate was the re-examination and what was the percentage of patients who were actually examined after 5 or 10 years?

With increasing availability of safe and early surgery, strangulation is a much less common event now. Patients tend to present earlier and bowel resection rates have also decreased.

As surgery becomes increasingly safe, the problems of persisting post-operative pain, quality of life, the ability to work, as well as the recurrence rate have become more important issues.(combined meeting of the European and America Hernia Societies June 2003 - London).

Extra measures to increase the strength and durability of the repair are being increasingly stressed. These include:

A.                 Suturing, with a modern synthetic monofilible non-absorbable suture. One variety of this technique is the Darn technique. There multiple layers are formed. Together with this some surgeons use a relieving incision in the anterior sheath of the rectus muscle to reduce tension on the suture line.  

B.         There has been an increasing reliance on the use of mesh in
             hernia repair. The most common mesh used is a polypropylene
             monofilament mesh, which is being used in some countries now
             in 95% of hernia repairs. The aim is that the non-absorbable
             monofilament sutures and mesh give immediate strength and
             allow early mobilization and return to work, particularly in the
             first month or two when the strength of the scar is being tested.
             The use of absorbable suturing has been largely discarded
             because it has been proved to be ineffective. Years ago people
             would be kept in hospital for many days or even weeks
             following hernia repair.  It was thought the mobilisation and
             exertion increased the risk of recurrence substantially because
             of the increased tension pulling the sutures out.

C.        The new techniques being developed with mesh rely less and
            less on the suturing and more on the design on the mesh and the
            placement of the mesh. The aim being to achieve smaller incision
            and less suturing, because it is felt that the suturing contributes to
            post operative and long-term pain.

The most popular technique worldwide now is the Lichtenstein technique (from Los Angeles).  This uses suturing to keep the hernia in its place but does not pull the muscles down to the inguinal ligament.  Once the hernia is replaced a mesh is then used to reinforce the whole area.  Thus was borne the term “tension free hernia repair.” 

The Lichtenstein technique has superseded the Bassini repair.  The muscles of the posterior wall of the inguinal canal were pulled down to the inguinal ligament under tension.  This technique has become very unfashionable because it is felt that there is too much tension on the suture line.  It has been shown that there is a high recurrence rate for the direct inguinal hernias using the Bassini repair. 

It is the suturing that keeps the hernia contents in place, but it is the mesh that gives the immediate and long lasting strength to the repair.

In this series the use of non-absorbable monofilament sutures for hernia repair has been advocated. These give immediate and lasting strength, particularly in the first month or two when the strength of the scar is till increasing.

As is refinements in both suture materials and mesh have occurred they have reduced the risk of infection. However, should infection develop, there is the risk of chronic sinus formation and the need to remove the sutures and mesh – a surgical disaster.

The Setting
The surgery can be carried out in specially designed free standing Day Surgery Units. Protocols for this have been very successful and increasing workloads throughout the world is taking place in such facilities. It has been shown that infection rates for day surgery are lower than for patients who remain in hospital. Careful planning is involved between the patient and the Day Surgery team.

Day surgery is also carried out at major hospitals where there is the option of keeping the patient overnight. This has some advantages for the elderly or with higher medical risks. It is pleasing however to see that day surgery has led to good results with fairly few readmissions because of careful selection.  The main cause for readmission has been postural hypotension or vasovagal fainting at home that evening.

The aim of day surgery is to give a good outcome and to reduce waiting lists and costs.

One of the major changes during the last few decades is the increasing importance of rapid mobilization, shorter stay in hospital and rapid return to normal life and the work force.

Pre Operative Assessment:
To achieve these short and long-term goals requires a thorough pre-operative assessment.

The patient should be assessed in the office for factors which might influence local complications e.g. Infection or bleeding, and factors that might lead to general complication such as lung or cardiac disease. Be aware of problems, which may actually predispose to the development of the hernia and may influence the risk of recurrence such as, obesity or even patients using steroids. There maybe problems present which make the use of local anesthesia an obvious advantage such as a previous history of deep vein thrombosis or factors, which may increase the risk of deep venous thrombosis.

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