Ventral Hernias in the Bariatric Patient

by David S. Wernsing, MD, FACS
Assistant Professor of Surgery, University of Pennsylvania, Pennsylvania Hospital, Philadelphia, Pennsylvania

INTRODUCTION
The management of primary and incisional abdominal wall hernias continues to evolve from the early days of primary hernia repair. There has been progress in the surgical approach to hernias with application of minimally invasive surgical techniques and an improved understanding of how to apply this to reconstructing abdominal wall defects. There has been development of synthetic meshes with a better understanding of the mechanical properties necessary for a secure hernia repair. There are also newer biomaterials that provide for tissue ingrowth and may be more resistant to infection than traditional meshes. This has allowed for opportunity to repair hernias during potentially contaminated operations that may have otherwise required a second operation to fix. Lastly, there has been a return to primary tissue repairs using component separation technique, augmented with mesh as necessary. This combination of education and materials has provided the surgeon with a basis of performing a better hernia repair.

Better appreciation of patient characteristics may help to support which type of procedure or mesh use will likely succeed. Risk factors for the development of abdominal wall incisional hernias may include the following: smoking, age great than 60 years, wound infection, re-laparotomy, chronic medical conditions (such as cirrhosis or cardiopulminary disease), and chronic steroid use. The relative ratio and amount of type I collagen may determine patients at risk.[1] Obesity is a risk factor for ventral hernias, both as a feature of their occurrence and as a factor in recurrence after repair.[2]

There has been exponential growth in the surgical treatment of obesity using laparoscopic and open techniques. There has subsequently been an increase in the number of patients who have had ventral hernias discovered at the time of their bariatric procedure and in the patients that develop incisional hernias as a result of their procedure. With improved recognition of these problems, surgeons are able to determine extent and timing of treatment, in order to minimize future patient morbidity.

The materials
In the early days of hernia surgery, surgeons recognized the inherent failure rate of primary ventral hernia repair to be as high as 20 to 30 percent (or 50% for primary repairs of recurrences).[3] Various suturing styles evolved, although recent studies indicate that a running nonabsorbable monofilament closure may result in the lowest hernia rates. Synthetic meshes using a multitude of constructs were developed in order to repair hernias in a tension-free fashion. These are primarily made of expanded polytetrafluorethylene (ePTFE), polypropylene, or polyester (and other polymer plastics) and have a variety of characteristics that lend themselves to different hernia repair techniques. In recent years, these types of mesh have been combined together in layers or with additional antiadhesion barriers. This is so they may be used in apposition to intra-abdominal contents and minimize adhesions while providing a different textured layer or material to encourage abdominal wall in-growth.

The latest mesh technology has provided for the development and use of biologic products, which have been fashioned from either human or porcine sources. There are multiple types of these products available for use by surgeons, all sharing nonallergenic, acellular characteristics. They differ in base structure, preparation technique, and use of cross-linking. These products have been made from human dermal matrix, porcine dermis, or porcine small intestine submucosa.

The potential advantage of these products over purely synthetic mesh is their ability to be incorporated into the native tissue and be replaced by the natural tissue surrounding the material. Vascular channels may facilitate the body’s ability to fight infection, making these products better than their synthetic counterparts in potentially infected or contaminated fields. While data look promising in this regard, the numbers are small and need to be validated over a longer period of time.[4–6] The benefits are not clear when using bioprosthetic as primary mesh to bridge fascial defects in noncompromised fields. There is concern that patients will develop laxity in the mesh repair that may ultimately lead to an abdominal wall deformity and dysfunction.

Hernia Repair in Obesity
With the recognition of obesity as a complicating feature of hernia repairs, weight loss counseling should be provided in patients that are planning on undergoing elective large ventral hernia repair. Weight loss may help to improve the technical circumstances of the operation and help to reduce the potential recurrence rate, though it may not change the risk of perioperative complications.[7] Expectation of weight loss and the time necessary for significant weight loss need to be balanced with the clinical indication for the hernia repair.

Optimum repair in this setting has been under debate although laparoscopic repairs done by surgeons skilled in laparoscopic ventral hernia repair have had better outcomes.[8,9] With laparoscopic approaches, there has been a decrease in recurrent hernias, decrease infection risk, and potential for a shorter hospital stay. With the need to visualize the complete extent of the abdominal wall defect during a laparoscopic repair, there is a better ability to identify occult hernias or attenuation of fascia (Figure 1) as sites of operative failure or long-term recurrence. It is important to incorporate transfascial fixation along with mesh overlap of 3 to 5cm to minimize recurrence. Using these strategies can decrease recurrence rates by 50 percent or more.[10]

Figure 2 and Figure 3 illustrate repairs utiliziing two different types of mesh.

Hernias identified at the time of surgery
There are a significant number of patients each year who undergo bariatric surgery who have either a ventral or incisional hernia identified at the time of surgery. In the past, if the hernia was not amenable to primary repair, repair was deferred until a later time. This was because of concerns of mesh infection in relationship to the open bowel portion that is a part of gastric bypass surgery. In a cohort of 85 patients, 38 percent of patients with deferred repair developed a small bowel obstruction, and even 22 percent of patients who underwent a primary repair developed a recurrent hernia. With the placement of a biologically derived mesh, there were no recurrences in short-term follow up (13 months average) and no mesh infections.[11] This needs to be balanced with potential for increased pain and inflammation of the abdominal wall, which may be confounding factors for complications in the postoperative period. There are times that a hernia will be exposed during the course of an operation that will mandate attention. Smaller necked, deeper hernias, with higher potential for incarceration, may be repaired primarily, accepting a higher recurrence rate to offset the risk of a mesh infection. Large, shallow defects can be deferred for later repair, while monitoring the patient for clinical symptoms related to the hernia.

There are no prospective studies evaluating the natural history of chronically incarcerated hernias that are discovered at the time of surgery and are then left undisturbed. One could argue that these hernias are best repaired in a minimally invasive fashion when the patient has undergone some weight loss or even at the time of abdominal wall plastic surgery, if planned. Further objective studies will need to be done in order to augment this supposition.

Hernia Prophylaxis in Bariatric Surgery
Hernia prophylaxis has been attempted as a means of decreasing the incisional hernia risk associated with weight loss surgery. There have been a limited number of studies using small numbers of patients that have demonstrated favorable results of prophylactic mesh placement.[12,13] Ventral hernia prophylaxis was originally done using polypropylene mesh. This was based upon some success from when the mesh was used to repair parastomal hernias and did not result in a significant increase in major would infections requiring mesh removal. There is still concern, however, that this may not be appropriate.[14]

Postoperative Hernias
There are two general avenues that patients may follow with regards to intervention of postoperative incisional hernias. The first is regarding the patient who develops an asymptomatic/minimally symptomatic hernia in the first 1 to 2 years after surgery and is planning on undergoing abdominoplasty or other type of body-contouring surgery. In these cases, hernia repair may be combined with their plastic surgery so that the patients need only undergo one anesthetic course. In addition, there may be significant laxity to the abdominal fascia, which may be reapproximated in a two-layer imbricating fashion that is typical of an abdominoplasty. If the defect is too large for a tension-free repair, mesh should be used as either an onlay or an underlay or repaired using a component separation technique. Overall, the hernia repair may be combined with the plastic surgery without significant increased risk.[15]

The second category is the patient who presents either acutely or has symptoms related to an incisional hernia. These patients should undergo repair in a relatively timely fashion, utilizing a laparoscopic technique if this is suitable to the skill of the surgeon and the complexity of the hernia repair. Delaying surgery for a time when the patient may be ready for plastic surgery may inhibit the patient’s recovery (and development of beneficial exercise habits).

Conclusion
Hernia development has a significant impact on the obese/post-bariatric surgery patient. Diligence in the clinical exam will minimize unanticipated problems in handling large hernias at the time of bariatric procedures. New mesh products and/or component separation techniques can allow for combining procedures so the patients will have the optimum recovery from their operation and the best chance for succeeding at their weight loss operation.

References
1.    Fachinelli A, Maciel T, Manoel R. Qualitative and quantitative evaluation of total and types I and III collagens in patients with ventral hernias. Langenbecks Arch Surg. 2007;392(4):459–464.
2.    Yahchouchy-Chouillard E, Aura T, Picone O, et al. Incisional hernias. I. Related risk factors. Digest Surg. 2003;20(1):3–9.
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4.    Holton LH 3rd, Kim D, Silverman RP, et al. Human acellular dermal matrix for repair of abdominal wall defects: review of clinical experience and experimental data. J Long Term Eff Med Implants. 2005;15(5):547–558.
5.    Franklin ME Jr. Gonzalez JJ Jr. Glass JL. Use of porcine small intestinal submucosa as a prosthetic device for laparoscopic repair of hernias in contaminated fields: 2-year follow-up. Hernia. 2004;8(3):186–189.
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11.    Eid GM, Mattar SG, Hamad G, et al. Repair of ventral hernias in morbidly obese patients undergoing laparoscopic gastric bypass should not be deferred. Surgic Endosc. 2004;18(2):207-210.
12.    Sugerman HJ, Kellum JM Jr, Reines HD, et al. Greater risk of incisional hernia with morbidly obese than steroid-dependent patients and low recurrence with prefascial polypropylene mesh. Am J Surg. 1996;171(1):80–84.
13.    Strzelczyk J, Czupryniak L. Polypropylene mesh in prevention of postoperative hernia in bariatric surgery. Ann Surg. 2005;241(1):196; author reply 196-197.
14.    Herbert GS, Tausch TJ, Carter PL. Prophylactic mesh to prevent incisional hernia: a note of caution.  Am J Surg. 2009;197(5):595–598; discussion 598.
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Tags: Surgical Perspective, Ventral Hernias

Category: Past Articles, Review