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The Lichenstein Amid Hernia Clinic at UCLA

Executive Director:
Parviz Amid M.D.

Clinical Director:
David Chen M.D.

Contact Information
1304 15th Street, Suite 213
Santa Monica, CA 90404
Phone: 310-319-4080
Fax: 310-394-5302

Ask The Doctor:

Email Dr. Amid at

Email Dr. Chen at

With Questions About Treatment

Description of Clinical Program

The Lichtenstein Amid Hernia Clinic at UCLA is the only facility in the United States devoted exclusively to research, teaching and surgery of abdominal wall hernias (inguinal hernia, femoral hernia, umbilical hernia, ventral hernia or incisional hernia). In 1984, internationally recognized hernia experts at the Lichtenstein Hernia Institute developed and popularized a revolutionary "tension-free" mesh technique, which is now accepted worldwide and considered the gold standard for hernia repair by the American College of Surgeons and European Hernia Society. All current forms of hernia repair both open and laparoscopic have their foundation in our concept of tension-free repair. In 2006, Dr. Amid brought the Lichtenstein Hernia Institute to the David Geffen School of Medicine at UCLA. Combining expertise in both open and laparoscopic techniques in the management of hernia repair, each patient receives individualized and personalized care to best treat their specific condition. With a focus on continuing our mission of clinical excellence while simultaneously promoting our academic goals of education and research in the field of hernia repair, the Institute was renamed the Lichtenstein Amid Hernia Clinic in 2011.  It continues to be a center of excellence devoted to the comprehensive management of all types of hernias.

Our Expert Team (photos and brief bios of all Physicians)

Parviz Amid, M.D., F.A.C.S.

Dr. Parviz Amid, a fellow of the American College of Surgeons and Royal College of Surgeons of England and Professor of Clinical Surgery at the UCLA David Geffen School of Medicine, is the Executive Director of the Lichtenstein Amid Hernia Institute. Dr. Amid was the cofounder of the Lichtenstein Hernia Institute and helped to define the modern era of hernia surgery. He is an instrumental figure in Herniology and established many of the principles of modern hernia repair and the treatment of chronic pain after hernia surgery. He is the cofounder and past president of the American Hernia Society. He has trained expert hernia surgeons from all over the world and has lectured across the United States and throughout Europe, Canada, Asia, South America, and Australia. He is an international expert on pain problems after hernia surgery.

Parviz Amid M.D.

David C. Chen, M.D., F.A.C.S.

Dr. David Chen, a fellow of the American College of Surgeons and assistant clinical professor of Surgery at the UCLA David Geffen School of Medicine, is the Clinical Director of the Lichtenstein Amid Hernia Institute. He was directly trained by Dr. Amid in proper Lichtenstein technique, complex hernia management and repair, and operative management of hernia pain. He has lectured and published on hernia repair and chronic pain after hernia surgery. He is an expert in both open and laparoscopic techniques for hernia repair and post-operative chronic pain. He is focused on treatment, education, and research for primary repair of hernias, advanced laparoscopic techniques for abdominal wall reconstruction and hernia repair, and surgery for chronic pain.

David C. Chen M.D.

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The abdominal wall is a sheet of muscle. When a weakness and defect occurs, the intra-abdominal contents bulge through: this is a hernia. Typically, small or large intestine or intra-abdominal fat herniates through the defect. Rarely, other abdominal organs can herniate. The most common symptoms are pain, swelling, or a bulge. If left untreated, hernias can incarcerate where the contents remain trapped in the defect or develop in to an emergency if the hernia strangulates causing symptoms such as pain, nausea and vomiting with intestinal blockage and compromise. For this reason, it is recommended that most hernias should be repaired in the elective setting.

Hernia is a tear, or hole, in the musculature of the abdominal wall (Figure 1).

Figure 1. The black spot represents the hernia opening 
in the muscular wall of the abdomen. The parallel lines 
represent normal muscle fibers.

In conventional methods of repair, the edges of the tear are stitched or sewn together to close the hole. (Figure 2). Unfortunately, simple suturing often recreates the tension that created the hernia causing pain and a higher risk of recurrence.

Figure 2.  Stitching creates distortion of muscle 
fibers and undue tension and pulling along the suture 
line, causing additional pain and making for a longer 
recovery period.  It can also lead to recurrence of 
the hernia.
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Tension-Free Mesh Method:

The "tension-free" mesh technique was pioneered by the Lichtenstein Hernia Institute in 1984 and is currently considered the gold standard of hernia repair by the American College of Surgeons. In this procedure, repair is accomplished by covering the opening of the hernia with a patch of mesh, instead of sewing the edge of the hole together (Figure 3).

Figure 3.  A polypropylene patch or screen covers 
the hernia completely and is tension-free.


The surgical mesh acts as a bridge or scaffolding for ingrowth of new tissue to reinforce the abdominal wall. Over time, the mesh safely becomes incorporated into the muscle layer, creating a very strong, permanent repair. In the standard Lichtenstein Repair, this mesh is placed between the layers of the abdominal wall. In laparoscopic repair, the mesh is placed behind the abdominal wall muscles. The mesh used by the Lichtenstein Amid Hernia Clinic is thin, flexible, and lightweight to decrease the risk of pain and foreign body sensation.

The Lichtenstein operation is typically performed under local anesthesia and on an outpatient basis. Within only two to three weeks, the patient's native tissue grows into the mesh, making it a part of the body (Figure 4).

Figure 4.  The entire area of the groin susceptible 
to hernia formation is permanently protected by the 
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Inguinal Hernia Repair:

Inguinal hernias are the most common type of abdominal wall hernia and typically present with pain or a bulge in the groin. Not uncommonly patients develop an inguinal hernia after heavy lifting or activity, coughing, or straining. These hernias occur more frequently in men and may be confined to one side or be present on both (bilateral). Patients with bilateral hernias may have them appear together or there may be a gap of many years before the second one becomes apparent.

While small, asymptomatic inguinal hernias can be safely observed, the natural progression typically involves enlargement of an inguinal hernia and development of symptoms over time. There are a number of possible ways to repair an inguinal hernia. Long term outcome studies have proven tension free methods pioneered by the Lichtenstein Institute to be superior. The repair of an inguinal hernia can be divided into open and laparoscopic procedures.
In the open Lichtenstein operation, an incision approximately 6 to 8 cm long is made in the groin. The hernia is identified and its contents are reduced back into the abdomen. The abdominal wall is repaired with a lightweight piece of mesh. Careful nerve handling is imperative and all nerves are meticulously identified and addressed at the time of the initial operation to significantly decrease the incidence of chronic pain. This operation is performed under local anesthesia. Outcomes of this technique have proven to be safe, cost-effective, reliable, and durable and it is the standard to which all other methods are compared.      
The laparoscopic repair of an inguinal hernia is an alternate standard method of hernia repair. Through three small incisions, the largest of which is 1 cm in size, the operation is then performed using a laparoscopic camera placing the mesh below the abdominal wall defect. This operation is performed under general anesthesia.    
Both open and laparoscopic repairs can normally be performed as outpatient operations (the patient goes home on the day of surgery). The type of repair depends on the individual patient’s presentation and preference. Both operations are offered at the Lichtenstein Amid Hernia Clinic with an informed discussion of the benefits and risks of each operation.
(Please see the FAQ on “Laparoscopic Versus Open Repair of Inguinal Hernias” under Resources for more information.)

Femoral Hernia Repair:

Femoral hernias are less common and occur more frequently in women.  It can be difficult to tell between an inguinal and femoral hernia. They are usually smaller and extend toward the thigh compartment. Because the defect through which the hernia has to pass is tight, there is a higher chance incarceration or strangulation. Therefore, early repair is typically advised.

Like inguinal hernias, femoral hernias are excellently suited to repair using a “tension free” technique. A mesh repair performed under local anesthetic is excellently suited for repair of femoral hernias and can be performed as an outpatient operation. Laparoscopic techniques may also be used to repair occult or recurrent femoral hernias. 

Umbilical Hernia Repair:

Umbilical hernias are usually present from the time of birth. Some are repaired in childhood while others enlarge slowly and present later in life. Most are small and asymptomatic and do not require repair. Bowel or omentum (intra-abdominal fat) may herniate through the defect and cause symptoms.

Using the same principles of tension free hernia repair, umbilical hernias over 2 cm in diameter should be repaired using mesh. Conventional techniques to repair these hernias by simply closing the defect with stitches place the muscle tissue under significant tension leading to higher rates of recurrence. The tension free version of this operation can either be performed by placing mesh behind the muscles as an open operation under local anesthesia or using a laparoscopic technique depending on the individual circumstance and preference. The navel is unaffected and patients are typically discharged on the same day as surgery.

Ventral Hernia Repair (Epigastric, Parambilical, Spiegelian, Incisional) and Abdominal Wall Reconstruction:

These hernias appear above the “belly button” and come through a defect in the midline linea alba- the fusion between the left and right rectus abdominis muscles (the “six pack” muscles). In epigastric hernias, typically intra-abdominal fat squeezes through a small hole in the linea alba. These hernias can be exquisitely tender but, due to the very small size of the defect, the risk of bowel herniation or incarceration is low. Paraumbilical hernias are usually larger than epigastric or umbilical hernias usually and require repair because of the risk of bowel contained within them becoming incarcerated or strangulated.

Both epigastric and periumbilical hernias can be repaired as an open or laparoscopic operation depending upon the individual presentation. Using the same principles of tension free hernia repair, epigastric and periumbilical hernias over 2 cm in diameter should be repaired using mesh placed behind the abdominal wall muscles. Surgery involves repair of the area of weakness and return of the abdominal contents back into their normal position. Small to moderate epigastric and periumbilical open hernia repairs can be performed under local anesthetic as an outpatient procedure. Laparoscopic repair may be indicated for patients with large defects, occult hernias, or larger body habitus.

Spigelian hernia

This is an uncommon type of ventral hernia that appears at the edge of the rectus abdominis muscle (the “six pack” muscles) where it fuses with the lateral oblique muscles.

Spigelian hernias can be repaired as an open or laparoscopic operation depending upon the individual presentation. Using the same principles of tension free hernia repair, Spigelian hernias should be repaired using mesh placed behind the abdominal wall muscles. Open Spigelian hernia repairs can be performed under local anesthetic as an outpatient procedure. However, this type of hernia is occasionally difficult to appreciate and laparoscopic repair may be indicated for patients with occult hernias or larger body habitus.

Incisional hernia

Whenever an incision is made into the abdominal cavity, the resultant scar even when fully healed, may not to be as strong as the original abdominal wall. If there is tension on the closure or problems with wound healing, the abdominal wall musculature may separate creating an incisional hernia. These hernias more frequently develop the setting of obesity, coughing, straining, infection, malnutrition, steroid or chemotherapy administration, and emergency surgery.

An incisional hernia can develop any time after surgery, most however become evident within 2 years of the initial operation. These hernias gradually increase in size and may become progressively more symptomatic. The size of an incisional hernia can vary significantly. Small hernia defects pose a greater risk of incarceration and strangulation while larger hernias may become progressively more symptomatic and increase in size over time. Medical evaluation of an incisional hernia is strongly advised.

Incisional hernias vary widely in size and complexity. A detailed surgical consultation is required for evaluation and determination of the correct treatment in each individual case. Small hernias may be approached open or laparoscopically depending on the location and contents. Larger hernias often require an abdominal wall reconstruction to lower the risk of recurrence. Effective surgery must follow the principles of a “tension free” repair with placement of mesh behind the abdominal wall muscles as these hernias develop in many cases as a result of too much tension at the original abdominal closure. Each case is reviewed individually to determine the optimal method of repair. Laparoscopic repair is often feasible for smaller defects. Larger repairs may combine a laparoscopic approach to reconstructing the abdominal wall with an open technique to reinforce the abdominal muscles and close the defect. Complex cases such as those with infection, prior failed repairs, coexisting ostomies, loss of abdominal domain, are all individually evaluated and repair is personalized to maximize the chance of successful repair. Review of prior operative reports and prior abdominal wall imaging is often helpful to help tailor each operation and should be brought to the initial consultation or submitted for review.

Hiatal Hernia Repair:

A hiatal hernia is different from other abdominal hernias in that the abdominal contents protrude into the chest cavity rather than to the outside world. The diaphragm is a sheet of muscle that separates the chest from the abdomen. Most often, a portion of the stomach protrudes upward into the chest through an opening in the diaphragm although with larger hiatal hernias, other organs such as the spleen, colon, pancreas, or small intestine can also herniate. Increasing age, obesity, and smoking are known risk factors in adults.

Hiatal hernias are very common, especially in people over 50 years old. Symptoms may include reflux, chest pain, heartburn, or difficulty swallowing. 

The goals of treatment of hiatal hernias are to relieve symptoms and prevent complications. Reflux is often controlled effectively with medications that neutralize stomach acidity, decrease acid production, or strengthen the lower esophageal sphincter. If conservative measures fail to control the symptoms or if complications such as pulmonary (lung) aspiration, iron deficiency anemia (slow bleeding due to a large hernia), or strangulation of the hernia occur, surgical repair is indicated. Typically, this type of hernia is optimally repaired using laparoscopic techniques. We have extensive advanced laparoscopic expertise in all variations of hiatal hernias and will individualize treatment in conjunction with our expert team of gastroenterologists, radiologists, and pulmonologists. 


Chronic groin pain is a serious problem after hernia repair. Nerve injury, entrapment, or reaction to mesh and scar may be the cause of severe pain syndromes. Dr. Amid is a world renowned expert on the causes, prevention, and surgical treatment of post-herniorrhaphy chronic pain and has treated over than 500 patients with these problems. He also has written and lectured widely on the subject. Dr. Chen has directly trained under Dr. Amid’s mentorship and has partnered with Dr. Amid to continue this specialized clinical program to treat patients with this debilitating problem. Each case is individualized and we employ a thorough and methodical approach to this complex problem. Non-operative measures are promoted and our UCLA Interventional Pain doctors have specific expertise in the non-operative management of this challenging condition. In cases that are unresponsive to conservative measures, inguinal neurectomy, mesh removal, and reoperation are all tailored to the individual patient. We have published extensively on this challenging problem and continue to refine operative technique to address the many different subtleties and complexities associated with inguinodynia. We have an ongoing clinical trial to help quantify pain and measure the improvement achieved with operative management. Our ongoing academic mission is to educate surgeons on proper nerve handling to decrease the incidence of this problem and continue our research to better treat patients with chronic post-herniorrhaphy pain.

Proper nerve handling at the time of initial hernia repair is crucial to decrease the incidence of chronic pain. In cases of refractory pain, reoperation to address nerve entrapment or mesh related complications is often needed.


Frequently Asked Questions

Q. Do all hernias require surgery?
A.  Hernias that limit activity or cause symptoms should be repaired. Small, asymptomatic hernias may be safely watched but will not go away without surgery. Most hernias will increase in size over time and may cause symptoms. In the absence of competing medical problems, most hernias are recommended to be fixed in the elective setting to address symptoms and prevent future complication.

Q. Is a hernia dangerous?
A. There is always a risk that an untreated hernia may lead to incarceration where the abdominal contents entering the hernia become stuck. This can lead to pain, nausea, vomiting, and constipation with intestinal blockage, and in rare cases necrosis of the herniated bowel. In these cases, the blood supply to the bowel may be cut off leading to it rupturing and the development of peritonitis. While this is an infrequent event, elective repair of at-risk and symptomatic hernias is recommended.

Q. What is the typical recovery after inguinal hernia surgery?
A. Modern surgical techniques including the open “tension free” Lichtenstein repair and laparoscopic inguinal hernia repair have led to rapid recovery. The length of stay in hospital and recovery times vary according to the extent of the operation and your general health, but most patients undergo outpatient surgery and are back to normal activity within a week. It is normal to take pain medications post-operatively to help with your recovery. Walking, movement, and routine activity are encouraged immediately after surgery. Strenuous activity should be avoided for 4 weeks after surgery.

Q. How are hernias repaired?
A. Surgery remains the only way to repair a hernia. Methods include open and laparoscopic repairs. Different mesh types are used as well as variations in technique depending on your individual case. Surgical options and their risks and benefits will be discussed with you t the time of your consultation. 

Q. Can my hernia be repaired without general anesthesia?
A. Yes. This is one of the many conveniences of the Lichtenstein operation. Most inguinal, femoral, and umbilical hernias can be repaired under local or regional anesthesia. Sedation may be administered based upon individual preference in consultation with our Anesthesiologists.
Laparoscopic repair requires a general anesthetic and temporary intubation with a breathing tube. For patients that prefer to avoid general anesthesia and those that have medical comorbidities that make general anesthesia higher risk, open surgery is preferred.

Q. What is the difference between laparoscopic and open hernia repair?
A. Like the open technique, laparoscopic repair is performed using a mesh. Unlike the open technique, the operation is performed through three small incisions, the largest of which is 1 cm in size with placement of the mesh behind the abdominal muscles instead of in-between the muscles. Laparoscopic surgery requires general anesthesia and bladder catheterization. Both can normally be performed as an outpatient operation.

Q. Can all types of hernia be repaired laparoscopically?
A. With inguinal hernias, if a patient has had a prior lower open abdominal operation (prostate surgery, Cesarean section, colon surgery) the scarring may preclude laparoscopic repair.
If a hernia is small and accessible, there is little difference in the amount of postoperative pain between an open and laparoscopic repair. An open operation is preferred as it avoids general anesthesia and entering the abdominal cavity.
If repairing a hernia requires a larger incision, a laparoscopic approach is probably beneficial. Inguinal, incisional, umbilical, paraumbilical, epigastric, and Spigelian hernias can all be repaired laparoscopically. Large defects however are often best managed with abdominal wall reconstruction to bring the abdominal muscles back to their natural location.

Q. Which is better open or laparoscopic inguinal hernia repair?
A. Open and laparoscopic operations are equally effective in repairing hernias. Open repair is safe, reliable, and avoids the need for general anesthesia and bladder catheterization. Laparoscopic repair has been statistically reported to have slightly less postoperative pain, less wound numbness, and an earlier return to work. There is a slightly higher recurrence rate with laparoscopic repair but both remain low. (Open < 1 %: Laparoscopic < 3%). Laparoscopic repair is advantageous in bilateral and recurrent cases. Chronic pain after inguinal hernia repair is possible with both types of repair. In cases where this occurs after laparoscopic repair, this may be more difficult to address due to the deeper position of the mesh. Each individual will have their own idea of which is the right approach for them and the benefits and risk of each will be discussed. With the Lichtenstein Amid Hernia Clinic both options are available to you.

Q. Will I be in pain after the operation?
A. With Lichtenstein and laparoscopic tension free repairs, there is significantly less discomfort post-operatively. However, this is still a major concern for patients and we take great care to minimize postoperative pain. All open repairs are usually performed under local anesthesia. This usually helps to minimize post-operative pain. In laparoscopic operations, local anesthetics are injected into incisions. More complex abdominal operations requiring inpatient admission are offered epidural anesthesia. We provide patients with painkillers to go home with. A combination of narcotics and ant-inflammatory medications is effective in minimizing pain. We recommend that these be taken regularly for the first 72 hours and then as needed thereafter.

Q. When will I be able to return to work?
A. This depends upon individual factor such as sensitivity to pain as well as the type of work you do. Typically, office workers whose jobs do not require much physical activity can usually return after a few days. Those with jobs that involve a lot of physical activity may require two or three weeks before returning to work.


What to expect

Your initial consultation
At your initial consultation, we will discuss your symptoms and presentation, examine you, and present options for management and repair. The benefits and risks of each procedure will be discussed with you. Resources are available on our website to help answer any additional your questions. You may contact us by phone or email should other questions arise

Your choice
When it comes to deciding which type of operation you prefer, we will give you plenty of time to ask questions and make up your own mind. You are free to decide on the method of repair up until the time of surgery.

Before surgery
You will receive a letter containing details of what you need to do to prepare for surgery. For most patients this will include details of where to go, what time to arrive, when you will be able to leave hospital and of anything you will need to bring with you. You will also be informed of the last time you can safely eat and drink prior to surgery. Typically, a pre-operative clearance from your primary physician is recommended.

The day of the procedure
On the day of surgery, before you go to operating room, you will be seen by your surgeon, the anesthesiologist, and the operating room nursing staff. Your surgeon will explain the procedure and you can ask any questions you might have. We will do everything we can to help you feel safe and comfortable.

After the operation
Most patients will go home the same day. A few patients require a longer hospital stay. If this is the case, your surgeon and the surgical team will see you daily until you are well enough to go home.

Experts around the clock
Following discharge, you will always have access to expert medical advice and can contact the hospital, the surgical team, or your surgeon at any time. If you have any concerns it is important you let us know since we can often address any issues or problems over the phone or arrange for you to be seen, day or night.


News & Publications

Peer Reviewed Journal Articles (Relevant Articles)

Amid PK, Chen DC. Surgical treatment of chronic groin and testicular pain after laparoscopic and open preperitoneal inguinal hernia repair. J Am Coll Surg. 2011 Oct;213(4):531-6.

Alfieri S, Amid PK, Campanelli G, Izard G, Kehlet H, Wijsmuller AR, Di Miceli D, Doglietto GB. International guidelines for prevention and management of post-operative chronic pain following inguinal hernia surgery. Hernia. 2011 Jun;15(3):239-49.

Amid PK, Hiatt JR. Surgical anatomy of the preperitoneal space. J Am Coll Surg. 2008 Aug;207(2):295.

Amid PK, Hiatt JR. New understanding of the causes and surgical treatment of postherniorrhaphy inguinodynia and orchalgia. J Am Coll Surg. 2007 Aug;205(2):381-5.

Amid PK. Causes, prevention, and surgical treatment of postherniorrhaphy neuropathic inguinodynia: triple neurectomy with proximal end implantation. Hernia. 2004 Dec;8(4):343-9.

Amid PK. Radiologic images of meshoma: a new phenomenon causing chronic pain after prosthetic repair of abdominal wall hernias. Arch Surg. 2004 Dec;139(12):1297-8.

Amid PK. Lichtenstein tension-free hernioplasty: its inception, evolution, and principles. Hernia. 2004 Feb;8(1):1-7.

Amid PK, Shulman AG, Lichtenstein IL. Open "tension-free" repair of inguinal hernias: the Lichtenstein technique. Eur J Surg. 1996 Jun;162(6):447-53.
Lichtenstein IL, Shulman AG, Amid PK, Montllor MM. The tension-free hernioplasty. Am J Surg. 1989 Feb;157(2):188-93.

Amid PK, Shulman AG, Lichtenstein IL. A simple stapling technique for prosthetic repair of massive incisional hernias. Am Surg. 1994 Dec;60(12):934-7.

Current Textbook Chapters:

Chen DC, Amid P. Technique: Lichtenstein. SAGES Manual of Hernia Repair, 1st Edition. 2012.

Amid PK, Chen DC. Inguinal Neurectomy for Postincisional Inguinal Nerve Entrapment. Mastery of Surgery. 6th Edition. 2012.

Amid PK, Chen DC. Lichtenstein Tension-Free Hernioplasty. Mastery of Surgery. 6th Edition. 2012.

Amid PK. Inguinal Neurectomy for Nerve Entrapment: Triple Neurectomy. Master Technique. 2012.

Our Locations (clinics and hospitals)

1304 15th Street, Suite 213
Santa Monica, CA 90404
Phone: 310-319-4080
Fax: 310-394-5302


Contact Us
If you would like more information, want to talk to someone about hernia surgery or want to make an appointment please call 310-319-4080

Dr. Chen:
Dr. Amid:


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