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Thoughts on Abdominal Wall Endometriosis
In my first year out of residency I practiced in Honolulu, HI. One day in my outlying clinic in Kapolei, on the west side of Oahu, I entered an exam room to find a woman crying in pain. She said she had pain in her belly wall that had been present for years and no doctor could help her or tell what was wrong with it. She said that several months after her last cesarean delivery she started to feel this hard lump on the side of her belly. Every month right before her menstrual cycle, this lump would become exceedingly painful, both at rest and even more so with any kind of pressure.
She was absolutely distraught, and was really in my office to ask for some narcotic pain medications to treat the severe pain. So many doctors had failed to make a diagnosis on this issue that she thought it was something she would have to live with for the rest of her life.
But, that day was different, because her doctor that day had been fortunate enough to be exposed to this condition in his training. The woman had abdominal wall endometriosis that had been ignored or missed for years. I scheduled her for surgery that afternoon and by that evening she was completely cured of the problem. I asked her as she woke up whether it still hurt, and she said that she felt some pain from the surgery, but the pain from that mass was gone. It felt good to help her, and I was thankful that I had gotten training in the diagnosis and management of this condition in my residency, something that is lacking in the training of most gynecologists in this country.
Since that time, I have been fortunate to be able to help a lot of women with this condition. The first few came randomly, and to my disappointment each one had been missed by at least a few doctors before I saw them. Eventually I became known as a competent manager of this condition, along with my general expertise in endometriosis, and at that point I started to see a lot of referrals and do a significant number of surgical repairs for this problem.
ORIGINS:
Abdominal wall endometriosis is a predominantly iatrogenic condition, meaning that it is the result of something that we are doing – and that something is cesarean delivery. The vast majority of these cases are subsequent to cesarean delivery, presumably via seeding of the abdominal incision with endometrial tissue at some point during the case. We do not know exactly what are the risk factors in cesarean delivery that cause this condition, but we do know from animal models that if you take a little piece of endometrium and stick it in the fascia when you close it after surgery, abdominal wall endometriosis will result – so presumably that is what is happening.
There are a few things I think we can do to reduce the incidence of this cesarean related endometriosis. Thorough irrigation of the wound prior to closure is likely to reduce or eliminate flecks of endometrium that might implant in the abdominal wall. I also believe, based on my experience but lacking data, that closure of the parietal peritoneum will reduce the incidence of this disease. I say this because of multiple experiences where uteri are adherent to the abdominal wall contiguous with masses of abdominal wall endometriosis. In one of these cases a hysterectomy was required to entirely remove the disease.
Interestingly, people with cesarean related abdominal wall endometriosis do not necessarily have typical peritoneal endometriosis, as it is caused by direct deposit of endometrium into the abdominal wall during a surgery. However, women that have abdominal wall endometriosis who did not have prior surgery most likely do have peritoneal disease, and it is probably severe. Papers suggest that only 50% of these cases are post-surgical, but in my experience cases without prior surgery are very rare.
DIAGNOSIS:
Abdominal wall endometriosis is a disease that is easy to diagnose if you know what the condition is and how it presents, and impossible to diagnose if you don’t. This is called availability heuristic – it is impossible to make a correct diagnosis if the disease state doesn’t exist in your brain’s medical knowledge banks.
In almost every case I have diagnosed, the patient came right out and told me they had it. Not literally of course, but rather they said the words that made the diagnosis certain. The disease presents with a hard mass that is painful at all times, but become larger and dramatically more painful prior to and during the menses. It is exquisitely tender to the touch, particularly during the most painful part of the month. With those symptoms, the diagnosis is almost certain. I can tell you that I have heard this story over and over and over, and I come right out and tell the patient what is wrong before I even look at their abdomen, and in each case it is there to be found on abdominal exam, just missed by well-intentioned people who didn’t know what to look for.
Imaging studies are useful in confirming the disease, though in my experience it is useful only to for surgical planning, as history is enough to make the diagnosis. The proper imaging should be an axial cut CT or MRI. MRI is better at showing the depth of invasion into the fascia and muscle, but either modality is adequate. If cost were an issue one could certainly get away without imaging. Some people (mostly general surgeons) will do a fine needle biopsy to confirm that it isn’t a malignant tumor, though I don’t think that is necessary and it drives up costs.
TREATMENT:
There are three things one can do with abdominal wall endometriosis, only one of which clearly leads to lasting cure of the problem.
As AWE is endometrial tissue, it will respond to high dose progestin therapy or continuous birth control pills. It will also respond to Depot-Lupron (leuprolide), and perhaps to aromatase inhibitors (eg letrozole). The upside is that these agents do work. The downside is that the patient is stuck taking them forever, or at least until menopause, and that they are not really treating the problem.
There are some recent trials that suggest efficacy in ultrasound guided injection of phenol directly into the endometrial tissue. These injections destroy whatever tissue they go into, so properly guided this probably does work. It is however something that is still in a research stage and only supported by a few recent papers (in international press.)
The final intervention, which is both curative and reliable, is surgical resection of the abdominal wall disease. In my experience, complete resection of the indurated tissue in the subcutaneous space, including resection of underlying fascia if necessary, is curative of the problem. I have had only one patient who did not experience complete relief, and subsequent imaging showed that she had a satellite area of disease that was not resected in the first surgery. She was cured in a subsequent surgery to remove this additional disease.
SURGICAL TECHNIQUE:
This procedure is performed under anesthesia by opening up the old cesarean scar, identifying the endometrial implants, and resecting them. In some cases the implant is superficial enough that removal does not require entry in the rectus fascia. In other cases the disease is invasive into the fascia or even the underlying rectus muscle, requiring resecting a portion of the abdominal fascia. Small fascial defects can be closed primarily, while larger ones can require mesh reconstruction of the fascia prior to closure.
I have removed quite a number of these, and in my experience about half require some level of mesh reconstruction. There are some studies that show a much lower likelihood than that, though I suspect they had a population with less severe disease than I have seen. My criteria for mesh reconstruction is a lack of ability to reapproximate the fascia without significant tension. I have predominantly used a biologic mesh (either Strattice (porcine dermis) or Veritas (bovine pericardium)) which is reabsorbed and replaced with fibrosis over time. Some operators use a permanent mesh. Permanent mesh is likely superior for large defects, though it comes with a chance of infection requiring removal. Porcine or bovine mesh will not get infected easily (if placed in a sterile field), but there is greater risk of subsequent hernia formation. We lack any randomized trials to direct us on exactly what type of mesh we should use in this diseases state, other than the general surgery literature on general abdominal wall reconstruction.
Placement of mesh is does by a simple inlay technique. I use 2-0 PDS suture to secure the mesh. Very large defects may require underlay or component separation techniques, in which case I will involve a general surgeon in the closure.
With the placement of any biologic mesh, drainage is imperative as seroma formation is quite common without it. Drains are left in place until drainage is minimal (10-20 cc a day), which can be as long as a month. My experience with inadvertent (gets pulled out accidentally) or impatient (resident pulls it out thinking that 50cc a day was little enough) has been consistently negative, with seroma reformation being common. While patients dislike drains, they can be managed, and they are preferable to a wound that is draining clear fluid for a period of time.
CONCLUSION:
If you are a physician seeing a patient with the symptoms I mention, please think about this diseases state. If you make the diagnosis you will be doing better than 90+% of people out there.
If you are a patient with these symptoms, tell your physician your own diagnosis. If they are not able to help you with it, consider visiting beautiful Portland, OR and I would be honored to help you.
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Dr. Fogelson is a gynecologic surgeon and endometriosis specialist who practices at Northwest Endometriosis and Pelvic Surgery in Portland, OR. Call 503-715-1377 for clinical consultation or email nfogelson@nwendometriosis.com. http://www.nwendometriosis.com
Academic OB/GYN 