- What is a hernia?
- Diagnosing hernias
- Groin hernias
- Midline hernias
A hernia is quite simply a ‘hole’ in the abdominal wall through which the internal organs may protrude. This results in a lump that is more obvious when the sufferer stands or coughs. The reason for this is that as the pressure inside the abdomen goes up it pushes the hernia contents out through the defect. Hernias can then become ‘strangulated’ when the contents of the hernia are unable to return to their normal place and hence lose their blood supply.
Over the last 100 years hernia surgery has developed into a medical speciality paralleled with huge leaps in technology and expertise.
This article describes groin hernias, recurrent groin hernias and midline hernias and discusses the latest treatment options.
Most hernias are apparent on examination by an experienced clinician although in some circumstances it may be necessary to get a radiological assessment. The radiological techniques used range from simple ultrasound through to MRI and CT. Imaging of this type may be necessary when planning complex abdominal wall reconstructions, when the diagnosis of a hernia is in doubt or in the setting of a recurrent groin hernia (see below).
Suspicion of a hernia merits immediate referral to a suitably qualified doctor.
These are the most common form of hernia encountered and can present at any time of life although they become more common with age. Classically they present as a lump in the ‘groin’ which may or may not be painful or indeed able to be ‘pushed’ back in. Once they occur they need to be assessed by a suitably qualified doctor and the majority will require a surgical repair.
Groin hernias may be associated with pain and if the hernia is not able to be pushed back in this constitutes a medical emergency due to the risk of strangulation.
There are two types of groin hernia:
• Inguinal hernias are so called because they occur in what is known as the inguinal canal, which is a tunnel passing through the muscles in the groin. They appear as a lump just above and to the side of the pubic bone.
• A femoral hernia is so called as it passes down the femoral canal and appears usually as a lump just below and to the side of the pubic bone.
The most common type of groin hernia is the ‘inguinal hernia’, which represents the bulk of groin hernia repairs performed across the world. Inguinal hernias are more common in men than women due to the passage of the structures supplying and draining out of each testicle passing through the layers of the groin muscles. This creates an area of potential weakness through which the hernia may form.
The less common type of groin hernia is the femoral hernia, which is more common in women than men and is usually found lower in the groin than the inguinal variety. This type of hernia merits urgent repair as it is more likely to strangulate - [contact doctor here]
The principle of repairing all abdominal wall hernias involves the placement of ‘mesh’, which is usually made of plastic. The mesh provides a durable reinforcement of the hernia defect and causes far less pain than previous non mesh repairs. The ‘mesh’ repair has led to a drastic reduction in the recurrence rates of groin hernia repairs and is relatively easy to perform. Most such operations are performed as a day case with the patient arriving and leaving on the same day. The incision is only 5-7cms in length and hence causes minimal cosmetic disruption. The meshes used in the groin have become thinner and more lightweight with improving technology in an effort to reduce the amount of foreign material implanted whilst not compromising on strength.
Approximately 5-10% of men have hernias in both groins either on the first presentation or on subsequent follow up (so called bilateral hernias). These may be repaired at the same time or on separate occasions, but if done together usually require an overnight stay unless done performing ‘keyhole’ surgery.
In some circumstances the operation is performed under ‘local’ anaesthetic and sedation. Here the surgeon injects a drug into the groin which renders the area ‘numb’ often in conjunction with a mild sedative which relaxes the patient and is administered via a vein in the arm. This local anaesthetic technique avoids the effects of having a general anaesthetic and is particularly useful in the elderly and unfit. After the operation the patient is encouraged to walk immediately once the effects of the anaesthetic have worn off and normal exercise is resumed within two weeks. The wound is closed with ‘dissolving stitches’ and simply needs to be kept dry for 5 days following the surgery.
If the repair is on one side only then 5-7 days are usually required off work but longer if hernias are repaired in both groins. Patients are advised to refrain from heavy lifting for approximately 2-3 weeks to allow the mesh to bond to the body.
Complications of hernia surgery are uncommon when performed in experienced hands but may include bruising (which may extend into the scrotum), infection, injury to the nerve supplying the small patch of skin on the top part of the thigh and a return (so called recurrence) of the hernia at a later date. In major units the recurrence rates of groin hernia repairs with mesh are less than 3% over 5 years.
For some patients with inguinal hernias who are not fit enough for a surgical procedure the hernia may be controlled with a ‘truss’. This is a pad worn on a belt which holds the hernia in place acting as an ‘external mesh’. Such devices usually need to be fitted for the individual and may be uncomfortable. A truss does not cure the hernia it simply keeps the hernial contents inside and is certainly inferior to surgery.
If the groin hernia recurs then any subsequent re-repair is far more complex. Once a repair has been performed the anatomy of the groin is permanently changed with dense scarring around the groin structures. This is why it is so important to reduce recurrence rates to the lowest level possible. The scarring found makes identification of the anatomy far more difficult and hence complication rates are far higher. Nerves are more commonly damaged and the risk of injuring the blood supply to the testicle is not insignificant (up to 5% in some series). In some cases this can lead to loss of the testicle altogether!
Repair of recurrent groin hernias needs to be done by a very experienced hernia surgeon and it is in this area that ‘keyhole‘ surgery is particularly helpful (see below). Conventional open or non-key-hole approaches to repairing recurrent groin hernias involve re-opening the old scar (usually under general anaesthetic) and placing a mesh over the defect. This can also be done as a day-case but often requires an overnight stay. Post operatively the doctor needs to be wary of complications particularly in men where the testicle blood supply may be in jeopardy. Any concern regarding the state of the testicle on the side of the operation should be reported to the surgeon immediately. Otherwise the post operation recovery is the same as for ‘first time’ repairs.
As laparoscopic or minimal access surgery (MAS) has developed for many operations it has become increasingly used for groin hernia repair. In MAS hernia repair the principles are very similar to conventional open surgery utilising mesh but it is placed through much smaller incisions. All MAS is performed under general anaesthetic and once the patient is asleep the first step of the operation is the insertion of a small plastic tube through the skin in the navel into the area behind the abdominal wall. This is followed by inflation of the abdomen with gas to create a space in which to operate. It is through this ‘port’ that the camera that allows the surgeon to see inside the abdomen is placed.
Two more small tubes are then inserted through the skin below the first in the midline to allow placement of the operating instruments. The posterior aspect of the groin is then exposed and plastic mesh is placed over the hernial defect and is secured in place by a few metal staples. The gas is then removed and the skin closed in a similar fashion to the open technique. The advantage of the MAS approach is less pain post operatively (particularly for bilateral groin hernia repairs which may then be done as day cases) and a faster return to normal activities.
The National Institute for Clinical Excellence (NICE) now states that all patients may be offered a MAS groin hernia repair if performed by a suitably qualified surgeon. Repair of recurrent groin hernias using MAS is especially effective as by approaching the hernia from the back the surgeon avoids the scarring that would be encountered from the front and hence may reduce the complication rate.
Hernias that occur in the midline of the abdomen are second in frequency only to groin hernias. Sutured repairs have now been superseded by mesh repairs, as found in the groin, and this has led to significant reductions in recurrence rates. The technological advances for midline hernia meshes allow them to be safely placed within the abdomen directly onto the bowel. This provides the most mechanically strong repair for what are often complex areas of weakness. These new meshes have a ‘nonstick’ surface’ on one side which makes placement on the bowel safe. These meshes are made of thin plastic although there is a move towards the use of biological material derived from animal tissue. The advantage of biological mesh is that it is more impervious to infection (particularly important in high risk cases) and eventually becomes incorporated into the patient’s own normal tissue.
Midline hernias vary from small ones found within and adjacent to the umbilicus and those more complex hernias that may arise as a result of poor healing of a wound after surgery (so called incisional hernias). All of these hernias are repaired using mesh, with the small ones done as day cases and sometimes under local anaesthetic. It is however the management of incisional hernias that is most complex either due to their size or involvement of the underlying intestine.
When a wound in the abdominal wall does not heal well a hernia can result. This can lead to protuberance of the underlying intestine through the defect which may be very large indeed. These cases need careful evaluation and may require the input of a team of surgeons consisting of general/abdominal surgeons and plastic surgeons. In some circumstances the muscles are so deficient that a plastic surgical reconstructive approach is needed in conjunction with the use of mesh. Such operations may take hours to perform and the patient may spend many days in hospital sometimes requiring intensive care support.
Depending on the patient’s size and the degree of overlying skin disfigurement, once the hernia has been repaired the plastic surgeon may need to perform a cosmetic reconfiguration of the overlying tissues akin to a ‘tummy tuck’. This partnership of reconstructive and aesthetic surgery leads to both a strong and cosmetically excellent outcome.
For selected patients with small midline hernias a MAS approach may be possible. Here 3 ports are placed usually on the patient’s left side and mesh is placed inside the abdomen over the hernial defect, secured with staples. Again these operations can be done as day cases and may lead to reduced postoperative pain and infection rates.
This technique is, however, really only effective in smaller hernias as the strength of the repair is based on the mesh only with no closure of the overlying defect. The complication rates of midline hernia repairs are higher than for groin hernias and this rises in conjunction with the size of the hernia. Most wounds are closed with dissolving sutures although metal clips may be used for the larger cases.
The problems of bleeding/bruising, infection and recurrence apply as before but with the incisional hernias there is always the possibility of injury to the bowel, which is fortunately a rare but described problem. Recurrence of midline hernias is more common than for those found in the groin, reportedly up to 15% depending on the size/type of hernia. Another problem is that fluid may collect in the tissues underneath the skin, so called seromas, which may be particularly problematic in large hernias. In order to reduce this when repairing large hernias a small plastic tube (a drain) may be left in the space left behind after the repair is complete. This may stay for a few days until relatively dry and then be removed either on an in or outpatient basis.
Most incisional hernias will need repair although some patients may elect not to undergo surgery or may not be fit enough for such a procedure. In these cases the patient may elect to simply wear a ‘corset’ which acts as a truss (see groin hernias) and will need to be ‘made to measure’.
The treatment of various types of hernia will vary depending upon the site and the nature of the problem although the principles of management are very similar. With improvements in technology and the establishment of specialist centres for hernia treatment patients should experience further improvements in outcomes.