Natural Tissue Hernia Repair vs. Mesh In Hernia Repair
At all times the human body tolerates its own natural tissues best, and hernia surgery is no exception.
The abdominal wall is a complex multi-levelled structure made up of distinct layers of muscle and fascia (tissue) designed to contract, stretch and bear tension in a way that allows the torso to bend and twist. Anything that restricts or interferes with the normal abdominal movement puts unnatural, and often harmful, stress on the area.
For over 100 years, non-mesh hernia repairs were the gold standard in hernia repair. From Bassini’s pioneering work in the 1880’s, through natural-tissue’s evolution by McVay and E.E. Shouldice, recurrence rates of hernia specialty surgeons improved to less than 1%, and complications and long term post-operative pain were virtually non-existent at less than 1%. The problem was that not all surgeons learned how to do natural-tissue repairs correctly, and recurrence rates were highly variable, with some as high as 20% and even 40%!
In response to these inconsistent results, the surgical community looked for a way to reduce recurrences for all surgeons. Although mesh made of a wide range of materials (silver, tantalum, kangaroo tendons etc.) had been experimented with as early as 1900, it was not until the production of synthetic meshes through the 1940’s and 50’s to include polypropylene, that mesh seemed to have become truly viable in hernia repair. In the early 1990’s, after extensive promotion by mesh manufacturers, and various surgeons citing low recurrence rates and ease of surgery, mesh grew to become the standard of care. The problem was that no one knew what the risks were as no one had studied the long-term impacts of implanted mesh.
The benefits and risks of the use of mesh in hernia repair is one of the most hotly contested topics in surgery today. Ground breaking research using the latest magnification technologies is currently being carried out to explore the complicated interactions of mesh within the human body, but through conventional research and observation we have become more informed on the relative merits and risks of using mesh in hernia repair. The literature is extensive, and is often contradictory, as commercial and self-serving interests combat science and objective research; however, the following is now generally held true:
- After 120 years of natural-tissue repair, and 30 years of established mesh repairs (25 years using of laparoscopy), all techniques are roughly equivalent in terms of hernia recurrence when performed by surgeons not specializing in hernia surgery. The advent of mesh has succeeded in reducing the overall recurrence rate by surgeons who on average do 50 cases or less a year, and who are not necessarily hernia specialists, to approximately 5%. Surgeons who specialize in high volume hernia repair produce consistently better results.
- Despite the improvement in the overall recurrence rate due to mesh in the hands of non-hernia specialists, it appears to have come at a needless cost to patients. Hernia centres specializing in natural-tissue inguinal hernia repair have met, and far exceeded, 5% recurrence rates, and Shouldice has done so for over 70 years. Although it is fair to conclude that mesh has reduced overall recurrence rates, the same result could have been achieved, or bettered, by continuing to use known and proven natural-tissue techniques in specialized hernia centres without the unintended post-operative consequences now attributed to the use of mesh, as outlined below.
- The known complications of using mesh are potentially significant, and are mostly attributable to:
- Foreign body reaction – mesh is a foreign substance and your body is constantly trying to defend itself by getting rid of it;
- Movement of the mesh – despite being anchored (stapled, glued or tacked) mesh can become loose and move, or migrate, throughout your groin or abdominal cavity. It can also fold, or be caused to move, as your body tries to eject the foreign mesh body;
- Mesh shrinkage – mesh repairs depend on scar tissue to grow into the mesh, forming a large layer of scar tissue. As the scar tissue shrinks, so does the mesh, creating a hard, fibrous mass with nerves embedded within it; and
- The nature of the mesh material – all mesh, regardless of weight or thickness, has fibres that create a lattice of holes or pores. During the normal healing process nerves regenerate and grow and can be trapped within the lattice structure. Over time, the mesh also hardens and become less flexible to the point where explanted mesh samples have become hardened plastic. Mesh can also adhere to surrounding tissue, nerves and organs. This is particularly true for mesh inserted laparoscopically. To combat this risk, mesh manufacturers added protective coatings on the mesh and developed absorbable and biological mesh. All these efforts have failed. Coatings dissolve, leaving the same polypropylene to cause its complications, with absorbable mesh ending in hernia recurrence in virtually all cases, as the mesh reinforcement deteriorates during its absorption.
These factors can cause the following devastating events:
- Chronic pain (arising or lasting more than 3 to 6 months from surgery) – the incidence of chronic post-herniorrhaphy pain in published literature is highly varied due to the inherent difficulties in defining and reporting individual’s pain levels. However, most studies agree that pain severe enough to bring a change in lifestyle, to cause a severe handicap in ordinary activities, or make life unbearable, is between 12% to 15% (some estimates are as high as 60%). The reality is that mesh does not have to be placed in the wrong place, or to function incorrectly, to cause pain. It is impossible for any surgeon when placing mesh to avoid contact with all nerves – this inherent limitation with mesh can produce pain through:
- Nerve entrapment or ingrowth in the mesh lattice – think of ivy as your nerves, growing through a screen door, and having the screen shrink up to 40% in the first 5 years and eventually to become a hard mass;
- Mesh fibres eroding over time and penetrating intestines, bladder, vas deferens or other vascular structures; and
- Chronic inflammation of tissues caused by the foreign body reaction and scarring.
- Dysejaculation (excruciating and searing pain during ejaculation), Sexual pain and orchialgia (long-term pain of the testes) as a result of movement or migration of mesh penetrating the layers of the spermatic cord and the vas deferens. In extreme cases, mesh can actually invade the entire spermatic cord causing pain. Infertility can also be a problem in bilateral inguinal hernias, and the results may not be seen for 7-12 years. These effects of mesh are irreversible. Since the general adoption of mesh in the 1990’s, the incidence of Dysejaculation has risen to 3.1%, a 7,750% increase from when natural-tissue repairs were the standard of care.
- Severe Infection – many of the coatings designed to protect the mesh have in themselves caused life threatening infections;
- Hernia recurrence – to be effective the abdominal wall must remain flexible as the torso twists and rotates. As mesh hardens, it becomes more rigid and has little tensile strength. This can cause the hernia repair to fail. In addition, absorbable and biological meshes, designed to minimize scarring and foreign body reactions, when used independently, have little long-term value. Recurrence rates have approached 100% for these products; and
- Complicated surgery to remove the mesh – mesh cannot be removed like peeling off a sticky note. Over time, it becomes embedded in the surrounding tissues and organs, and its removal can involve risky surgery with uncertain results and consequences.
Although there are inherent risks in any surgery, there are no similar or comparable risks in natural tissue hernia repair, where mesh has to be peeled off a bladder, colon, a spermatic cord or a major blood vessel. Scar tissue of natural tissue left in place represents no risk, while mesh left behind can continue its erosion and potential migration within the body.
So, after all the above does mesh have a place in hernia surgery? The fair answer is “yes”.
All surgeons strive for the best surgical outcome, and there are times when the patient’s underlying tissue is so weak, damaged or non-existent that their natural tissue cannot support the hernia repair without mesh reinforcement. In these cases mesh can be an alternative.
However, this decision must be based on surgical necessity, and then, only after a thorough examination of the patient’s underlying tissue, and full assessment of the risks and benefits of using mesh. Mesh should never be used because it’s easier, faster, cheaper or due to lack of familiarity with, or expertise in, the use of natural-tissue techniques!