Inguinal hernia

Inguinal hernias are a protrusion of either abdominal or pelvic contents through a dilated internal inguinal ring or weak inguinal floor into the inguinal canal and usually, although not always, out through the external inguinal ring (Burney, 2022). This type of hernia usually gives rise to a visible or easily palpable bulge in the groin area or the scrotum.

Inguinal hernias are thought to affect 27% of men but only 3% of women during their lifetime, with only about 10 per 100 000 of the UK population undergoing surgery for inguinal hernias (Fitzgibbon and Forse, 2015).

Not all inguinal hernias are symptomatic – about one in three people with an inguinal hernia are unaware one of it (Vacca, 2017). The onset of symptoms, where there are any, may be either sudden or, as is more common, insidious.

The signs and symptoms of inguinal hernias include:

• Pain – usually unilateral and ‘burning’ in the lower abdomen and/or back, thigh, perineum and scrotum
• Discomfort – described as a dull feeling in the groin or pelvis (Shakil et al, 2020).

Symptoms may only be present or heightened by activities such as coughing, during exercise, straining on the toilet or when walking upstairs (Vacca, 2017). Symptoms may improve when the affected person lies down and, conversely, may worsen during the day when undertaking regular activities.

There appear to be two processes which contribute to the aetiology of inguinal hernias. The first is genetic predisposition, where specific genes that also play a role in the makeup of connective tissues have been shown to increase susceptibility (Öberg et al, 2017). The second risk factor relates to increased intra-abdominal pressure that occurs when conducting the Valsalva manoeuvre (straining against a closed glottis) (Öberg et al, 2017). This accounts for the increased risk for people who are constipated.

Some people are more prone to inguinal hernias, including individuals who:

• smoke
• live with chronic obstructive pulmonary disease
• are chronically constipated
• have a low body mass index
• are pregnant
• have a genetic predisposition
• are white
• are older
• have had previous open surgery for appendectomy
• are on peritoneal dialysis (Fitzgibbon and Forse, 2015; Vacca, 2017)

Diagnosis is usually clinical, where the affected person would present with a reported swelling (palpable on examination) and discomfort (Burney, 2022). It is often easier to diagnose an inguinal hernia if the person is standing and asked to cough or bear down in a Valsalva manoeuvre, so that the hernia can be seen and palpated (Shakil et al, 2020).

In some cases, the diagnosis is not clear and may require imaging (eg an ultrasound, computed tomography or magnetic resonance imaging) of the groin. Imaging scans are most often needed to confirm diagnoses in women (Shakil et

The management of an inguinal hernia will depend on presentation, with acute presentations - including hernias which are incarcerated or strangulated - requiring emergency surgical repair (Fitzgibbon and Forse, 2015; NICE, 2022).

Small asymptomatic hernias may be subject to a watchful waiting management approach, although many people with these hernias will eventually require surgery (Fitzgibbon and Forse, 2015), including cases where the hernias are reducible (NICE, 2022).

A herniorrhaphy surgery is the only definitive treatment for inguinal hernias, usually involving reinforcing the posterior wall of the inguinal canal with a mesh, most often made of polypropylene (Berndsen et al, 2019).

Large or symptomatic but uncomplicated hernias must be treated with planned, elective surgery. Surgery can often be a day case and may involve local, spinal or general anaesthetic, depending on the extent of the surgery and the patient characteristics, with local anaesthesia reportedly reducing complications (eg postoperative

NICE (2004) indicated that patients need to be fully appraised of the risks and complications associated with surgery for inguinal hernia repair. Postoperative complications following herniorrhaphy for inguinal hernias are uncommon, and may relate in part to how closely the patient follows the postoperative instructions.

Immediate complications can include:

• swollen or painful testes and/or base of the penis
• pain or numbness in the groin

Both of the above complications usually resolve without any treatment in a short period of time. Surgical infections are said to be rare, so prophylactic use of antibiotics is not common (Berndsen et al, 2019). Acute dysuria (usually in men with a prior history of urinary tract problems) is uncommon, as is postoperative bleeding (Berndsen et al, 2019).

About 10% of inguinal hernias are recurrent, with about 2–4% recurring within 3 years (Köckerling et al, 2016). This rate has been reduced as a result of

Balentine CJ, Meier J, Berger M, et al. Using local anesthesia for inguinal hernia repair reduces complications in older patients. J Surg Res. 2021;258:64-72. https://doi.org/10.1016/j.jss.2020.08.054 

Bendavid R, Lou W, Grischkan D, et al. A mechanism of mesh-related post-herniorrhaphy neuralgia. Hernia. 2016;20:357–365. https://doi.org/10.1007/s10029-015-1436-8 

Berndsen MR, Gudbjartsson T, Berndsen FH. Inguinal hernia - review. Laeknabladid. 2019;105(9):385-391. https://doi.org/10.17992/lbl.2019.09.247 

Burney R. Inguinal hernia in adults. 2022. https://bestpractice.bmj.com/topics/en-gb/723 (accessed 25 May 2023)

Fitzgibbons RJ, Forse RA. Groin hernias in adults. New England Journal of Medicine. 2015;372(8):756-763. https://doi.org/10.1056/NEJMcp1404068 

Köckerling F, Stechemesser B, Hukauf M, et al. TEP versus Lichtenstein: Which technique is better for the repair of primary unilateral inguinal hernias in men? Surg Endosc. 2016;30(8):3304-13. https://doi.org/10.1007/s00464-015-4603-1 

Mouravas V, Sfoungaris D. The etiology of indirect inguinal hernia in adults: congenital, acquired or both? Hernia. 2015;19:1037–8. https://doi.org/10.1007/s10029-015-1365-6 

National Institute for Health and Care Excellence (NICE). Laparoscopic surgery for inguinal hernia repair: Technology appraisal guidance [TA83]. 2004. https://www.nice.org.uk/guidance/ta83