This investigation will be a double-armed, randomized prospective study designed to compare open (Lichtenstein Technique) versus laparoscopic (TAPP) repair of primary unilateral inguinal hernia. Chronic pain, restriction of activities and esthetical outcome will be evaluated preoperatively and postoperatively, at 1, 4 and 12 months, using the European Registry for Abdominal Wall Hernias Quality of Life score (EuraHS-QoL score).

Inguinal hernia repair is one of the most frequently performed surgical operations. Since the introduction of mesh repair, recurrence rates have fallen dramatically and chronic pain, as a side-effect of surgery, is becoming increasingly important.

Chronic pain is defined as pain or discomfort that lasts for more than 3 months after surgery. The reported incidence of chronic pain varies between 0 and 75 per cent after open mesh repair, and between 0 and 29 per cent after laparoscopic repair. Prospective trials suggest that there is less chronic pain after laparoscopic than open repair.

Although pain is an important parameter determining the Quality of Life (QoL) after a hernia operation, other aspects, like restriction of activities and esthetical outcome, are also of importance.

This investigation will be a double-armed, randomized prospective study designed to compare open (Lichtenstein Technique) versus laparoscopic (TAPP) repair of primary unilateral inguinal hernia.

Chronic pain, restriction of activities and esthetical outcome will be evaluated preoperatively and postoperatively, at 1, 4 and 12 months, using the European Registry for Abdominal Wall Hernias Quality of Life score (EuraHS-QoL score). The EuraHS-QoL score is a validated hernia specific questionnaire with 9 questions that can be scored by the patient in an 11-point scale from 0-10. The EuraHS-QoL questions are divided in 3 domains: "Pain" (range 0-30), "Restriction of activities" (range 0-40), and "Esthetical discomfort" (range 0-20). The total score ranges from 0-90, with the lower scores being the most favourable outcome.

The EuraHS-QoL score can be downloaded in several languages from EuraHS web pages ( http://www.eurahs.eu/EuraHS-QoL-download.php). EuraHS QoL score was previously validated and the results have been already reported in Surgery (Muysoms FE., Surgery. 2016 ;160:1344-1357)

Up to 216 patients will need to be enrolled for this study (n=108/group) and each subject will be followed for up to 12 months after the surgical intervention. The sample size was calculated to explore differences in chronic postoperative pain between the groups, accepting an α risk of 0.05 and a statistical power defined as 90 per cent (β risk = 0.1) in a two-sided test.

The study will be carried out at the Hospital Plató in Barcelona (Spain). Hospital Plató is a district general hospital serving an aggregate population of over 150.000. Hospital surgery department undertakes conventional open and laparoscopic treatment for inguinal hernia on a regular basis.

The hernia repair will be performed in all patients of both arms using the same lightweight polypropylene mesh (Optilene® 60 g/m2 ; B. Braun, Melsungen, Germany): A tailored 7.5 × 15 cm mesh for repairs in the open Lichtenstein arm, and a tailored 15 x 15 cm mesh for all patients in the laparoscopic TAPP arm. To avoid biases, meshes will be fixed in all patients (both groups) by applying liquid drops of n-butyl-2-cyanoacrylate (Histoacryl®; B. Braun Surgical, Rubí, Barcelona, Spain).

Inclusion Criteria:

• primary inguinal hernia
• unilateral hernia

Exclusion Criteria:

• bilateral hernia
• recurrent hernia
• incarcerated hernia
• large scrotal hernia
• known femoral hernia
• need for associated procedures
• not able to understand the questionaire
• immunosuppression (including corticosteroids, radiotherapy, chemotherapy)
• chronic renal failure (hemodialysis)
• active infection
• pregnancy
• allergy to polypropylene or cyanoacrylate
• patient's refusal and/or absence of informed consent