NIS

Critique of Tension Free


The abdomen is a pressurized elastic container. Wall tension of this container is described by the Laplace Equation:

T = P•R
Wall tension

Where T is wall tension, P is interior pressure and R is the radius of curvature of the wall.

No where in the abdominal wall does wall tension equal zero because nowhere in the abdomen does P equal zero, except when the patient is asleep. But this a trivial situation which has no meaning in real life.

This common misunderstanding is used to sell mesh. When mesh is placed and the patient is asleep there is no tension. After the operation when the patient is awake it is a completely different situation. Mesh is effective only in as much as it bears tension. Mesh seals itself to the tissue that it supports by inciting chronic inflammation. This chronic inflammation never stops. In 20% of patients this chronic inflammation results in chronic pain which also never stops.  Proponents of mesh say that their recurrence rates are less than 1/2% as if that is all that matters. Chronic pain that occurs in as many as 20% is a serious problem which is not justified by an absolute difference of 2% in recurrences. It is faulty thinking that is unbecoming of our profession.

Proponents of mesh also refer to non-mesh repairs as old fashion tension repairs. We have had mesh since it was first patented in 1954. For decades there was very little interest in it until the early 1990's when manufactures found a way to effectively market it. They got famous surgeons who were recieving royalities from the manufacturers to call it "The Standard of Care" essentially telling all other surgeons that the debate was over and that everyone should fall in line or risk being accused of not practicing the standard of care. This surgeon bristled at being told that his tried and true technique should be abandoned in favor of putting an untested synthetic material into his patients for at best a minor reduction in recurrence and at worst no one knew. We now know chronic pain is the problem. Chronic pain was not reported in the medical literature and recognised as a real problem until 1998. Before that time mesh ascended to the standard of care and now there are very few surgeons who know how to effectively repair a hernia without mesh. It is a dysfunctional situation which is perpetuated by big money.

One of the problems with mesh is that it’s properties of elasticity and compliance poorly match natural tissue. That is, it does not bear tension like natural tissue. This mismatch of mechanical properties causes stress and is one of the mechanisms by which mesh causes chronic pain. Also stress at the mesh–tissue boundary causes tissue disruption leading to a new hernia.

Imagine fixing a bicycle inner tube hole with a steel patch. The patch will never fail but the rubber inner tube will not bear the patch. The best patch for an inner tube is a rubber patch that matches the properties of the inner tube.. If it could be preformed the best repair would be to restore the defect. This is the principle of a non-mesh hernia repair.

The most ideal hernia repair restores the defect without changing anatomy or physiology. This is the principle of a transversalis based repair such as the Basinni, the McVay and the Shouldice. The so called tension free repairs are not tension free in reality. They obliterate anatomy and massively distort normal physiology.