Surgical Options in the Repair of Ventral and Incisional Hernias

Perhaps in all aspects of surgery, hernia repair provides the greatest conundrum with respect to choices of materials to use (or not) and techniques that may be utilized to achieve the desired result.  When it comes to discussing the component separation technique, even the desired result has been changed.  I am going to attempt to explain each of the options for ventral abdominal wall hernia repairs with respect to advantages and disadvantages, indications and contraindications for each of the methods to be discussed.

To Mesh or Not to Mesh?

 For the overwhelming majority of ventral hernias, some sort of mesh will be necessary.  Pulling tissue together under tension that for some reason has already developed a defect assuredly will only lead to a recurrence.  Not to mention the pain caused by pulling the abdominal wall tightly closed.  Additionally, the pressure applied on intra-abdominal organs will push on the diaphragm and may lead to respiratory difficulties.  In fact, it is the development of mesh that has lead to the ability to effectively repair large abdominal wall defects in a single procedure.  The possible exception to this is the case of a small umbilical hernia in which many cases the defect is only about the size of a quarter or even smaller.  Under these circumstances the tissues are easily re-approximated in a double layer of fascia with sutures and without tension.  Some surgeons will place a small mesh plug in these defects and suture that in place for the repair.  Under these specific circumstances, I will usually avoid a mesh and rely on a mesh only in the event of a recurrence. 

Choice of Mesh

Now begins the fun.  There are at least 50 different varieties of mesh available on the market, and I have representatives from each of these companies coming to my office weekly to tout the benefits of their mesh.  So, which to choose?

The main disadvantage of any mesh is the possibility of infection because of placement of a foreign body.  There are four basic categories of mesh and I will discuss each of these with respect to risk of infection, cost and efficacy. 

Plastic Mesh- Prolene, Mersilene or other types of plastic mesh are very inexpensive and are effective in repairing even large abdominal defects.  They cannot be left in direct contact with abdominal viscera because the adhesion formation will be intense and the risk of a fistula development is significant.  Either of these complications can be extremely difficult to treat in the face of an incorporated mesh.  The mesh causes a very intense reaction with tissue and the mesh becomes invested within a very dense scar which leads to a good repair of the hernia. 

 

Gortex- For the fellow skiers out there, this is what your gloves are made of.  In the case of hernia repair, a gortex patch makes an effective repair of a hernia defect and it may be left in contact with the abdominal viscera.  It does not incorporate into tissue like prolene, and it often causes the formation of seroma.  In the event of an infection involving a gortex patch, the gortex separates easily from the surrounding tissues unlike prolene or mersilene.  Gortex is slightly more expensive than prolene or mersilene mesh.  Because gortex does not incorporate as intensely into tissue, it is not a good choice for large hernias, as the repair will always be dependent on your fixation sutures and not the dense scar that forms with mesh. 

 

Collagen-  Collagen is the protein matrix that all of our cell sit upon.  Without collagen we would disintegrate.  In fact there are many diseases of collagen metabolism which cause a variety of maladies for the human species, but this is for an entirely different discussion.  Collagen matrices are used for hernia repairs and can be obtained from a variety of human and non-human sources.  They are very expensive.  For example a piece of plastic mesh that costs a couple of hundred dollars may be $10,000 if it is made of collagen.  Collagen mesh; however is very resistant to infection.  One's own cells grow into the collagen matrix and serve as the basis for the hernia repair.  Because of its cost, collagen mesh is most useful in situations where there is contamination or infection already present where a hernia needs to be repaired.  The typical circumstance is an incarcerated, strangulated ventral hernia where there is gangrenous intestine that must be removed.  Placement of a prolene of gortex mesh carries virtually 100% risk of infection (Nothing is ever 100%, but you get my drift).  Before the advent of collagen mesh one would either just pull the wound together under tension, or use an absorbable mesh and accept the immediate recurrence of the hernia in about 3 to 6 weeks.  Collagen mesh allows for the repair of the hernia even under these circumstances with a < 10% risk of infection.  Even if an infection occurs it can be treated with antibiotics and local wound care with an acceptable result. 

 

Aside from the cost of collagen mesh, they also tend to be rather lax and tend to stretch over a short period of time.  So while they may help repair a complex abdominal wound, the result may still be a bulging abdomen which may later need another repair with a synthetic material.

 

Composites- The development of laparoscopic techniques for the repair of ventral hernias has necessitated the development of mesh products appropriate for those techniques.  As stated above, prolene causes a very intense reaction from tissues it is left in contact with but when placed adjacent to bowel may cause serious complications.  Gortex doesn't adhere to the bowel, but it doesn't really integrate with the tissue of the abdominal wall very well and may not be reliable for repairing a large defect.  Collagen is very expensive and may stretch over time and once it is incorporated into the patient's own tissues may in fact become just a large hernia sac. 

 

What if a mesh could be made that takes advantages of properties of one type of mesh on one side and another type of mesh on the other?  That is what a composite is.  There are composites of gortex and prolene, gortex and "other plastic" mesh, collagen and "plastic mesh" etc.  Thus on one side you have a component that is safe to leave within the abdomen as it will not cause too severe adhesions with the intestines, while the other side will evoke an intense reaction with the abdominal wall leading to a good hernia repair. 

 

It should be noted that the peritoneum will rapidly grow over a collagen or gortex mesh left on the inside of the abdominal wall and protect the abdominal viscera.  Prolene or Mersilene however, though they also will become peritonealized, still evoke a very strong inflammatory response resulting in dense adhesions.

Choice of Fixation Material-

As we are beginning to see the topic of hernia surgery is rife with choices. 

 

Non-absorbable sutures- Most commonly utilized with open methods for fixing a hernia by direct tissue approximation with or without a mesh.  One would want to use a non-absorbable suture to give lasting strength to the points of fixation of the mesh as well as tissue to tissue.  Chief disadvantage is that the tails of the suture where they are tied, if left poking upwards toward the skin, particularly in a thin person, may cause discomfort if they begin to erode into the skin.  They may even come to poking through the skin necessitating a minor procedure to trim back the tails.  However; sutures poking through the skin may provide a pathway for bacteria to invade and cause a mesh infection.  Fortunately, with just a little care and forethought, there are techniques for placing the sutures in such a way that the tails are buried in the subcutaneous tissue rendering this complication one of academic importance only.

 

Absorbable sutures- These have the advantage of disappearing over time but also have the disadvantage of disappearing over time.  If your entire repair depends on the fixation of the mesh to native tissue with sutures I would be a bit hesitant to use sutures that will be gone in a short period of time.  On the other hand, as I will discuss below, depending on the surgical method to be employed for repair of the hernia, there may be a place for absorbable sutures.

 

Titanium, non-absorbable tacks- Laparoscopic Hernia repair is much more easily performed because of the development of tacks for fixation of the mesh.  These are tiny cork screw shaped tacks which are deployed through the mesh and fixate the mesh to the abdominal wall.  The titanium tacks are non-absorbable, are compatible with MRI and are completely inert in tissue.  They have two main disadvantages.  Firstly, should a tack cause pain because of its placement, the pain is not likely to resolve short of injection of the local nerve supply to the area.  Secondly, and more theoretically, the ends of the tack are sharp, and I for one am a little reticent placing a sharp tack in the abdominal wall where the abdominal viscera may rub against it.  To my knowledge there has never been perforation of intestine or a fistula that has developed because of a hernia tack. 

 

Absorbable Tacks- These are made of material similar to absorbable suture.  The tacking device with tacks, are at least double the cost of the equivalent device with titanium tacks.  However; in my humble opinion, the cost is worth the diminished worrying about placing 30 or 40 sharp tacks around a hernia repair, in the abdomen.  I have no hesitation in using titanium tacks, however when doing a Laparoscopic Extra-peritoneal Hernia Repair with mesh as these tacks are outside of the abdominal cavity and are in contact with nothing.   Absorbable tacks are gone in about 6 weeks, have a flat head but do no burrow as deep into tissue as do the titanium tacks, thus possibly necessitating the use of more of them. 

Choice of Suture Method- This is probably beyond the scope of an article intended for a lay audience but I can't seem to help myself.  There is some contrary about what follows but I include it for the sake of completeness. 

Interrupted Suture- Throw a stitch and tie it, plain and simple.  The disadvantage is that for a large defect, you have to throw and tie a lot of sutures.  This can be rather slow and tedious.  The advantage is that if any one stitch should break or the knot should slip, your whole repair is not disrupted.

 

Running Suture- Throw the stitch, tie the knot and throw, throw, throw through mesh and tissue all the way around until you come back to your starting point where you tie the ends together.  Much quicker to perform than interrupted suturing but should the stitch break or come loose through weak tissue at any point, you run the risk of your entire repair coming undone.  Also, if you pull a running suture too tight as you go you may cause ischemia in the native tissue to which you are suturing your mesh.  This may be a cause of recurrence.

 

Combination- There are all kinds of combinations that exist.  This may consist of U- sutures, figure of eights or running sutures to each quarter of the mesh or part way down a wound. 

Choice of Surgical Methods-

Confused yet?  Read on.  There are several options for where to place the mesh and how to do so.  These are influenced by the size of the defect, the patients underlying condition and overall medical status and of course, surgeon preference.  I will discuss each of these with the advantages and disadvantages of each.

 

Onlay Method- (see a) The subcutaneous tissue is dissected off of the hernia sack and off of the external fascia layer several centimeters back from the edge of the defect all around the entire defect.  The hernia sack may then be opened to dissect adhesions if the patient is having obstructive symptoms.  The sack should be preserved and closed so as to provide a barrier between the mesh and the abdominal viscera.  If the fascia will come together without undue tension this can then be done.  A mesh is placed over the fascia and sutured in place with two rows of suture.  If the defect was not repaired primarily,  then it is essential that the first row of sutures be placed around the defect and close together so as not to allow the sack or abdominal contents to pass between the anterior fascia and the mesh.  Then an outer layer of sutures is placed along the edge of the mesh to secure the mesh to the fascia.

Advantages- Easy to perform.  Does not require extensive undermining of extra-peritoneal layer. 

 

Disadvantages- Requires a lot of suturing to secure the mesh around the defect and then onto the surface of the fascia.  Significant incidence of seroma formation over the mesh.  May require placement of drains over mesh to avoid seroma formation.  Most important is the fact that mesh secured to the outside of the abdomen is at a mechanical disadvantage against intra-abdominal pressure and gravity pushing against the mesh, and may lead to recurrence.

Inlay Method- (see b) Essentially the same as the onlay method except that the mesh is secured to the edges of the defect only. 

Advantages- Easy to perform.  Does not require extensive undermining of extra-peritoneal layer. May be adequate for relatively small defects.  Less mesh in patient therefore less seroma formation and perhaps less risk of infection.

 

Disadvantages- Suturing to the edge of the defect may involve sutures in attenuated and abnormal tissue.  Again there is a mechanical disadvantage against intra-abdominal pressure and gravity which may lead to recurrence, especially if this method is used over large defects. 

Underlay Method- (see c) The mesh is placed inside the fascia in the extra-peritoneal plane.  

Advantages- Mechanical advantage against intra-abdominal pressure and gravity obtained by placing mesh inside of defect with large overlap of mesh under fascia.  Mesh not in subcutaneous tissue may result in lower risk of seroma and/or infection

 

Disadvantages- Difficult dissecting pre-peritoneal space over broad area to make room for mesh.  Difficulty in suturing or tacking mesh under fascia (though there are mesh products that make this easier). 

Laparoscopic Method- Using a camera and small incisions mesh is placed in the peritoneal cavity over the defect with large overlap. 

Advantages-   Again achieves mechanical advantage against intra-abdominal pressure and gravity by placing mesh inside defect with large overlap.  Small punctures only for instruments used to do surgery. As with all Laparoscopic procedure there is a shorter recovery and return to normal function.

 

Disadvantages- Placement of mesh can be difficult but there are techniques for making this fairly routine.  Since the mesh is under the peritoneum, virtually all patients develop a seroma.  Some surgeons will aspirate the seroma in the office though in most cases the seroma resolves on its own over time, but sometimes a long time. 

Component Separation- The subcutaneous tissue is dissected off the fascia beyond the edge of the insertion of the external oblique fascia into the rectus sheath.  A relaxing incision is made in the external oblique fascia just beyond that insertion point and continued along the entire length of the muscle from the costal margin (just below the ribcage) to the iliac crest (the pelvic bone).  The layer under the external oblique muscle is then freed up separating the external oblique muscle from the internal oblique and allowing the rectus to move several centimeters toward the midline.  Another similar incision may then be made internally through the inner rectus fascia allowing that layer to be turned toward the midline and both sides sutured together.  This may be combined with an underlay mesh and/or an overlay mesh sutured to the cut edge of the external oblique.  There is a laparoscopic method for performing the dissection of the external oblique fascia which may lessen some of the risks of this surgery. 

Advantages-   Unlike any of the other procedures discussed prior, this operation brings the rectus muscle back to the midline and returns to the patient a functional abdominal wall.  Results are excellent even for patients with huge hernias. 

 

Disadvantages- This is extensive surgery and is best for those with a primary incisional hernia involving most or all of the mid-line.  Recurrent ventral hernias often involve missing tissue and this procedure may not be suitable for patients who have had a prior incisional hernia repair if there is significant loss of rectus fascia. The undermining of the skin and subcutaneous tissue as extensively as described may carry the risk of cutting off the blood supply to the skin and subcutaneous tissue overlying this area.  This risk is higher in thinner patients.  The results could be quite problematic especially if one has left a plastic mesh overlay as it will now be exposed if the skin should undergo necrosis.

In writing this article my intent has been to educate and not to confuse.  I hope I have done more of the former than the latter.  Understand that there are no absolutes and the final choice of which method to use for any particular patient's hernia will of course, be between the patient and the surgeon.  There is more information about the anatomy and causes of Ventral Hernias in our Education Section.

Steven P. Shikiar, MD, FACS email