Chronic groin pain (CGP) is a recognised risk associated with inguinal hernia surgery. It can be present before groin hernia surgery, but can also persist and arise as a consequence of groin hernia surgery.
The causes of CGP are generally multifactorial and can arise after either laparoscopic ‘keyhole’ or open groin surgery, with the latter having a greater risk of post-operative groin pain. CGP is defined as persistent pain in the groin at least three months after groin hernia repair. The true incidence of CGP has been defined as anything from 5-10% of patients after inguinal hernia surgery but the incidences reported in the contemporaneous literature have been quoted as between 1-63%, with the quality of life of up 10% of patients being affected.
The common causes of CGP are briefly discussed below:
If a hernia recurs the assessment is normally made clinically and on some occasions a groin ultrasound is required. The hernia repair can be carried out by either keyhole or open techniques with the former being commonly employed especially if the first operation has been carried out via open surgery. In most cases redo surgery after keyhole surgery is carried out via the open technique.
Mesh related pain
Previously inserted mesh can also give rise to pain in the groin, this can be as a result of mesh irritation, mesh infection, a meshoma (contraction of the mesh) development and mesh ‘entanglement’ of the nerves. If the mesh becomes infected this will commonly present with a persistent wound infection and a non-healing wound. Mesh irritation of the vas deferens in men, which may present with orchitis (testicular pain), this can occur with either open or keyhole techniques.
In most cases CGP will most likely be due to a combination of mesh related factors along with nerve irritation or damage. Both magnetic resonance imaging and sometimes CAT scanning may help elucidate any mesh related causes of CGP.
The three nerves most commonly affected in CGP include the ilioinguinal, iliohypogastric and the genital branch of the genitofemoral nerve which all arise from the lumbar plexus. Pain or discomfort is felt in the area supplied by the nerves and nerve mapping will help identify which nerves are more likely to have been affected. There is a recognised cross over of the nerves sensory distributions so any nerve pain surgery with division of the nerves will involve dividing all three nerves. When mesh is placed at the time of open inguinal hernia surgery it is difficult to predict which patients will be affected with pain as a result of mesh contact with either or both of the ilioinguinal and genital branch of the genitofemoral nerves. Pain can also arise as a consequence of an unrecognised injury of a nerve, mesh ‘entanglement’ of a nerve as well as the nerve(s) being ‘caught’ in a stitch. Pain can also be caused around the outside of the thigh by damage to the lateral cutaneous braches of the femoral nerves, which are more likely to be injured after laparoscopic surgery. The pain experienced can be either nociceptive (discomfort or irritation) or neuropathic (sharp on touch or pressure).
For Dermatome mapping and pain intensity scores click here.
It is never clear as to the true cause or aetiology of CGP, but some factors have been documented in the literature as possibly having an increased incidence of CGP. The aim of a consultation will be to determine whether any of these factors may have a causal role in the occurrence of CGP.
- Open surgery with the use of non-absorbable (permanent sutures/stitches).
- Open surgery with division of the hernia sac rather than its reduction.
- Open surgery with suture being placed into the pubic bone when fixing the mesh.
- Keyhole surgery with use of permanent or traumatic fixation of the mesh by using TACKS or staples.
- Younger patients with pain prior to surgery.
- Post operative haemorrhage (bleeding) at the time of the initial inguinal hernia surgery leading to severe swelling of the scrotum, base of penis and groin.
- In open surgery the use of lightweight mesh has been shown to decrease the risk of CGP.
It is important to realise that there may be additional psychological factors that may be a cause of CGP. Most patients do experience a sense of feeling low as a result of their ongoing pain and at times this can affect their quality of life. It will be important to ascertain any factors that may be affecting the pain experienced. CGP is a recognised multifactorial entity with many possible factors that can cause the discomfort experienced.