What causes groin hernias to come back?
Well, as noted repeatedly on the Advanced Hernia Specialists website, inguinal (groin) hernia repair is one of the most common surgical procedures all over the world. Today, hernia repair is performed many different ways, using several different modalities (see different types of surgery on our site). An article published in the International Journal of Surgery in June of 2013, titled "Recurrence after groin hernia repair-revisited" was a large review study where the authors performed an analysis of all previous research articles published on hernia recurrence for the preceding 40 years.
"Success of groin hernia repair is measured primarily by the permanence of the operation, fewest complications, minimal costs, and earliest return to normal activities. Of all the factors used to compare the various methods of inguinal hernia repair, the incidence of recurrence is most often held as the measure of success."
The authors noted that "recurrence rates of over 15% for primary [open] repair" were accepted before the mesh techniques were introduced, and that after the use of nonabsorbable mesh implants (in both open and laparoscopic repairs), the recurrence rates dropped significantly. But even with the decrease in recurrence rates, they do still occur, and the authors wanted to evaluate what factors lead to these recurrences.
So, in their analysis they found that the incidence of recurrent hernia after primary [open] repair of a groin hernia varies from 1% in specialized centers to up to 30% in general surveys. Before the introduction of mesh to hernia repair, it was estimated that primary inguinal hernia repairs had a 10%–30% recurrence rate and that the rate was as high as 35% for recurrent hernia repairs. Those numbers are astonishing, aren’t they?
The Lichtenstein mesh hernia repair has been considered the “Gold Standard” technique for very many years, and still is to this date. It has been the repair to which all others have been compared. Results from 3019 repairs from 5 sites have demonstrated a 0.5% recurrence rate with this repair. That’s pretty hard to beat.
This study looked at many factors that have been proposed to lead to hernia recurrence. They looked at each one independently. Specifically, they looked at:
Experience of the surgeon
Type of “suture material”
General condition of the patient
Smoking and chronic cough
Growth factors (naturally occurring factors of wound healing)
Size of the hernia
Dissection of the muscle of the spermatic cord and hernia sac
Missed hernias at the time of operation
Weakening of the femoral canal with repair of other groin hernias
The use of mesh
Location of the recurrence and its relationship to initial repair
Length of time before return to normal activity after repair
Recurrence after laparoscopic (minimally invasive) repair
Technical errors of surgeon
a. Incomplete dissection
b. Inappropriate fixation of mesh
c. Placing slits in the mesh (to accommodate anatomic structures)
If we look closer at some of the more important variables:
A surgeon’s experience has been shown in many studies to play a huge role in the recurrence rate. Surgeons who specialize in hernia surgery and have had many years of experience have been shown to have better outcomes than those who do not. See "How do I chose the right surgeon?" at AdvancedHerniaSpecialists.com.
“Tension” caused by pulling tissues in the inguinal canal together, which is routinely necessary in repairs without mesh, results in compromise of the blood supply to those tissues. Compromise of the blood supply to the tissues results in the death of those tissues under tension, and when that tissue dies, it no longer holds the sutures. If the tissue doesn’t hold the sutures, then the repair simply falls apart and the hernia comes right back. Along those same lines, typically the tissues that are forcibly sewn together are weak in the first place (hence the hernia) and are prone to having the sutures tear through when they are pulled together under tension. So, in the same way, the tissues come apart and the hernia comes right back. And even small technical details as to the way the suture is tied by the surgeon can contribute to failure. When mesh is used, there is NO TENSION, and the mesh reinforces the tissues that we already know are weak in the first place. This is one of the main reasons that the recurrence rate is so much lower with mesh. See "Tissue vs Mesh Repair."
The surgical wound gains approximately 80% of its final strength after 6 months, and therefore we know that the wound and repair needs to have support for at least that time. So, the choice of suture by the surgeon is important because it must stay present for at least that time. Most surgeons use absorbable sutures now, for many reasons, but most absorbable suture lasts less than a month. We do have absorbable sutures that last up to 9 months, so it is incumbent upon the surgeon to use appropriate sutures, and many surgeons do not.
Obviously, the same holds true if mesh is used. Most meshes used for groin hernia repairs are permanent (non-absorbable), so as long as it is placed correctly, it should support the repair indefinitely. If absorbable mesh is used, again, it should last for at least 6 months minimum before being absorbed.
It is well known that chronic smoking leads to a higher recurrence rate after hernia repair, predominantly due to impaired wound healing in smokers that results from decreased oxygen and the many chemical changes in the human body caused by smoking.
Large hernias have over twice the recurrence rate of smaller ones, mainly because of the increased damage to the surrounding inguinal (groin) tissues from the long-term stretching and tearing. This is one of the many reasons to have a hernia repaired when it is first diagnosed, and not waiting for it to become much worse and more bothersome as it becomes larger. Hernias always become larger over time. The larger they get, the more difficult they are to repair, and perhaps obviously, the more likely they are to recur after repair.
Another significant factor noted was also surgeon experience related, and that factor was either missing the hernia in the first place (thus not repairing it) or failing to recognize an additional hernia at the time of the initial repair. It is not that uncommon that a person may have more than one hernia, or more than one type of hernia, and therefore it is critical to look for them, and recognize them at the time of surgery. If a hernia is missed, and not repaired, then obviously the patient still has a hernia (so not exactly a recurrent one in this case).
As noted earlier, the choice of mesh is also important. Mesh technology has been evolving rapidly, especially over the last 5-10 years, and we have more and more meshes available to chose from. It is therefore important for the hernia surgeon to be familiar with the newest mesh and mesh technologies in order to be better able to choose the best and safest mesh for the type and location of the hernia. See "Is Hernia Mesh Safe?" for a great summary of mesh and mesh technology. Also see "Is it necessary to use hernia mesh?"
So, in the end, after analyzing all the information from many studies, the authors concluded that for the patients that experience recurrence of their hernia early in the postoperative period, the factors that most contributed to recurrence were, 1. Failure on the part of the surgeon (technical errors), 2. tension on the suture line, and 3. Infection (which is still very uncommon, but leads to a very high recurrence rate when it occurs).
Of the recurrences that occurred much later after repair, even years later, the authors concluded that they most often result from “tissue failure,” meaning that the tissues that are repaired simply get weaker with age and develop thinning of scar tissue over time. This continual weakening is then combined with the already known weakness that is inherent to the tissues of the inguinal region in general, and the hernia repair doesn’t last. Again, another endorsement for the use of mesh. Mesh never gets weak. See "Is it necessary to use hernia mesh?"
As far as laparoscopic (minimally invasive repairs), the authors also noted that surgeon skill and experience are most important. Factors such as correct dissection, proper mesh size, and proper placement of the mesh were found to be of critical importance in preventing hernia recurrence.
So you see again, choosing the right surgeon plays a very large role in having your hernia repaired the right way the first time, which then results in a significantly lower chance that your hernia will come back. See “How do I choose the right surgeon?” at AdvancedHerniaSpecialists.com
Gopal SV, Warrier A. Recurrence after groin hernia repair-revisited. Int J Surg. 2013;11(5):374-7. doi: 10.1016/j.ijsu.2013.03.012. Epub 2013 Apr 1. PMID: 23557981.