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Research at the Penn Hernia Center

The Hernia App developed at the Penn Hernia Program allows surgeons to evaluate patients considering surgery to ascertain their relative risk for incisional hernia
The Hernia App developed at the Penn Hernia Program allows surgeons to evaluate patients considering surgery to ascertain their relative risk for incisional hernia
The Hernia App developed at the Penn Hernia Program allows surgeons to evaluate patients considering surgery to ascertain their relative risk for incisional hernia.

Researchers at the Penn Hernia Program are conducting clinical studies with the object of developing a more comprehensive appreciation of the patient experience and quality of life (QOL), improving outcomes for first-time hernia repair, and preventing or avoiding incisional hernia (IH) in patients at risk.


Of all abdominal hernias, incisional hernia (IH) is perhaps the most common. The risk factors for IH have been documented since the dawn of modern surgery. They include (but are not limited to) age >60 yrs; BMI >25Kg/m2; male gender; trauma; smoking; co-morbidities (diabetes, jaundice, cancer, chronic respiratory and gastrointestinal disease, immunosuppression); concomitant medications (corticosteroids); type of surgery (emergent procedures, transplant surgery, bowel resection, abdominal aortic aneurysm repair, stoma closure, appendectomy); surgical technique and materials (midline abdominal incision, open abdomen with delayed closure); complications of surgery (infection, wound dehiscence); and biological factors (collagen synthesis, increased intra-abdominal pressure resulting from cough, obesity, ascites or bladder obstruction).

Despite recent and continuing improvement in surgical technique, procedure and materials, the incidence of incisional hernia remains high. Of the more than one million abdominal surgeries performed in the United States each year, ~10% will develop incision hernia necessitating repair (typically with mesh implantation) within three to five years. Of these surgeries, 30 to 40 percent will recur, requiring re-repair. Individuals who have had previous hernia repair are at increased risk for further complications, including bowel obstruction, incarceration (in which visceral materials become entrapped at the hernia site), and intestinal strangulation. 

“To the critical eye, it’s obvious that hernia is a chronic disease state,” says Penn plastic and reconstructive surgeon John P. Fischer, MD, MPH, a surgeon and clinical researcher at the Penn Hernia Program. “People have a hernia, have it fixed, and the repair eventually fails or develops complications and so begins a cycle of morbidity and recurrence, deterioration of quality of life, disability, chronic pain medications and costs.”

Quality of Life (QOL)

Given the risks and complications of incisional hernia, QOL is a substantial consideration for patients having these surgeries. Yet very few reports of QOL following IH exist. To address this dearth, Dr. Fischer and collaborators across Penn Medicine, including Francis Barg, PhD, MEd, of the Mixed Message Research Lab, initiated a qualitative inquiry among IH patients at Penn to assess QOL. 

The result was the creation of the Abdominal Hernia-Q (AHQ), a question-based patient-reported outcome measure to assess a series of objective and subjective responses linked to QOL. The AHQ was established by a rigorous effort to capture stakeholder input from patients, family members, nurses and physicians to establish a comprehensive overview of the potential health states relevant to hernia. This information was then refined to inform the key words and concepts for the conceptual framework of the AHQ, including expectations, function, appearance, overall satisfaction with the provider-patient relationship and perceptions of post-repair improvement, among other goals.

“Essentially, what the AHQ offers is a patient-informed, psychometrically-validated instrument that can be used in the clinical setting,” says Dr. Fischer. “It’s my hope that this becomes the standard of care for quality of life in patient-reported outcomes for abdominal hernia.”

A Model for Hernia Risk and Prevention

Another principal focus of research at the Penn Hernia Program involves preoperative IH prevention, a series of measures, including weight reduction, smoking cessation, individualized strategies for surgical approach and technique and other steps taken before surgery to reduce complications thereafter.

“The risk factors for hernia have been well documented across most surgery types,” Dr. Fischer says. But, he adds, knowing the risks identified with specific surgeries and knowing the risks for an individual are very different things. A healthy 34-year-old with a BMI of 26 having first surgery and a 64-year-old with three prior abdominal surgeries, diabetes, and a BMI of 37 present very different scenarios for risk.

“The issue is that surgeons haven’t had access to a risk assessment tool that offers a patient’s risk for post-operative hernia in real-time,” Dr. Fischer says. 

To address this discrepancy, the Penn hernia research team gathered data on age, race, health, physical condition and prior surgical and medical history from ~78,000 patients having hernia surgery at Penn over a five-year period. This information was used to develop a series of risk models subsequently published in peer-reviewed journals [1-3] that were incorporated into a smart phone app known as the IH Predictor. Using the app, a surgeon can predict a patient’s potential risk for hernia in real-time prior to surgery and incorporate preventative measures and shared decision-making into his or her surgical strategy.

“Like our studies in QOL, our objective in developing the IH predictor was to inform clinical practice,” Dr. Fischer says. “We’ve done studies of prophylactic reinforcing mesh, for example, that suggest that there’s a lot that can be done differently to enhance preoperative IH prevention.”

For more information about hernia repair at Penn Medicine, call 267-758-4822, or visit the Penn Hernia Program.

Dr. Fischer discusses the Penn Hernia Program in a new video Complex hernia repair.

Accruing Clinical Trials at the Penn Hernia Program

The Penn Hernia Program is participating in several accruing clinical studies, including:

The XenMatrix™ AB Surgical Graft in Ventral or Incisional Midline Hernias Trial [NCT02691962]

The objective of this study is to prospectively explore the use of XenMatrix™ AB Surgical Graft for ventral or incisional midline hernia repair in patients across all wound classes through 24 months post-repair. The XenMatrix™ AB Surgical Graft is an acellular, sterile, non-pyrogenic porcine dermal matrix packed dry for use in the reconstruction of soft tissue deficiencies. The device surfaces are coated with the antibacterial agents Rifampin and Minocycline in a bioresorbable L-Tyrosine succinate polymer carrier.


1. Fischer JP, Basta MN, Mirzabeigi MN, Bauder AR, Fox JP, Drebin JA, Serletti JM, Kovach SJ. A Risk Model and Cost Analysis of Incisional Hernia After Elective Abdominal Surgery Based on 12,373 Cases. Ann Surg 2016;263:1010–1017.

2. Weissler JM, Lanni MA, Hsu JY, Tecce MG, Carney MJ, Kelz RR, Fox JP, Fischer JP. Development of a Clinically Actionable Incisional Hernia Risk Model after Colectomy Using the Healthcare Cost and Utilization Project. J Am Coll Surg 2017;225:274-284.

3. Tecce MG, Basta MN, Shubinets V, Lanni MA, Mirzabeigi MN, Cooney L, Senapati S, Haggerty AF, Weissler JM, Hernandez JA, Fischer JP. A risk model and cost analysis of post-operative incisional hernia following 2,145 open hysterectomies—Defining indications and opportunities for risk reduction. Am J Surg 2017;213:1083-1090.


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