Ninety-five percent of patients are male, with incidence variation from 11 per 10,000 person years (aged 16–24) to 200 per 10,000 person years (aged 75 or above) [3].

The lifetime risk of developing an inguinal hernia is 3% for women and 27% for men [1]. The incidence rises with age and is eight times higher in persons with a positive family history [7].

The following risk factors have been described [8]:

Lateral, medial, and femoral hernias are anatomically distinct from one another and arise at different frequencies [6]. Indirect hernias are twice as common as direct ones; femoral hernias account for less than 5% of all inguinal hernias (more common in women). Inguinal hernias are more often on the right side than the left [5, 9].

Obturator hernias account for 0.07–1% of all hernias and 0.2–1.6% of all cases of mechanical obstruction of the small bowel [10]. They have the highest mortality rate of all abdominal wall hernias (13–40%) [11].

Spigelian hernia accounts for 1–2% of all hernias; supravesical hernia is very rare (with few cases described in literature) [12, 13].

A complete anamnesis is the first step to a correct diagnosis, and the following points are crucial: groin swelling (right/left), nature and duration of complaints (pain), contralateral groin swelling, symptoms of incarceration, reducibility, and previous hernia operations.

Predisposing factors must be investigated: smoking, chronic obstructive pulmonary disease (COPD), abdominal aortic aneurysm, long-term heavy lifting work, positive family history, appendicectomy, prostatectomy, and peritoneal dialysis [14].

A reducible (with proper maneuver) groin swelling (above the inguinal ligament) is definitive evidence of an inguinal hernia and needs no further diagnostic evaluation with the exception of physical examination [2].

Physical examination of the groin is mandatory not only in patients referred for lower abdominal pain; it consists of inspection (ipsi- and contralateral swelling, operation scar, skin signs of incarceration), followed by palpation of the patient’s groin in both standing and lying position, including digital exploration of the inguinal canal as afterward described and digital rectal exam. An inguinal hernia can be distinguished from a scrotal hernia (with or without hydrocele by palpation, using transillumination if necessary).

Evaluation must include testicle and spermatic cord bilateral palpation, inguinal canal exploration made by a finger into the external inguinal ring (at rest and during Valsalva maneuver), and palpation of bone and muscular-aponeurotic landmarks (pubic crest and tubercle, pectineal line, superior pubis ramus, inferolateral and superomedial pillar, common rectus abdominis-longus adductor muscle aponeurosis). In a recent study, a standardized questionnaire was used to evaluate symptoms of patients with inguinal hernia and in a control group [15]. Sixty-nine percent had discomfort in the hernia itself and 66% in the groin, while 50% complained of increased peristalsis, without any difference between right-sided, left-sided, or bilateral hernias. Only 7% had no symptoms. Patients with a left-side hernia complained mainly of increased peristalsis and tenesmus, while patients with right-side complained of urinary problems. The preoperative symptoms and the severity of pain in the early postoperative period were both risk factors for chronic pain [16].

Any non-reducible inguinal mass needs further diagnostic evaluation, even in asymptomatic patients. A meta-analysis confirmed the utility of ultrasonography for this purpose, with 96.6% sensitivity, 84.8% specificity, and a positive predictive value of 92.6% [27]. In a study of 36 patients with occult hernias, magnetic resonance imaging was found to be superior to both ultrasonography and computerized tomography [17].

Dynamic sonography is useful (low cost, good diagnostic value, and availability), but can only be stated as a grade C recommendation (suboptimal quality of studies).

Differential diagnosis to be considered is femoral or incisional hernia, lymph node enlargement, aneurysm, saphenous varix, soft tissue tumor, abscess, genital anomalies (ectopic testicle), adductor tendinopathy, pubic osteitis, hip artrosis, iliopectineal bursitis, low back pain, and endometriosis (in female patient) [14].

The European Hernia Society (EHS) Board agreed on a new classification based on Aachen system [18].

EHS classification defines the location of hernia with L (lateral), M (medial), and F (femoral). The size of hernia is indicated with 1 (≤1 finger), 2 (1–2 fingers), and 3 (≥3 fingers). For two different hernias in the same patient, appropriate boxes in the table are ticked. In addition, P or R letter is encircled for a primary or recurrent hernia.

No matter which classification system is used, the type of hernia should be recorded according to intraoperative findings, describing each side separately and clearly for bilateral hernias.

Surgical procedures for inguinal hernia repair could be classified according to technique (primary tissue repair with suture or mesh positioning), to anatomical approach (anterior or posterior), and to type of surgery (open or laparoscopy/endoscopy).

Minimally invasive procedures are always done through a posterior approach and with the use of a mesh; open, primary tissue repair procedures are performed through the classic anterior approach. Bassini, Shouldice, and Desarda are suturing techniques; the standard mesh technique through an anterior approach is Lichtenstein [22].

The “plug and patch” technique and the use of special mesh systems (prolene hernia system, PHS) in open procedures to cover both the anterior and the posterior surface have been recently reviewed.