This is a randomized, double blind, controlled study. The aim is to compare postoperative inguinal pain using the Inguinal Pain Questionnaire (IPQ) validated in Spanish and Numerical Pain Scale in postoperative patients with Lichtenstein and Onstep technique at 1 week, 1, 3 and 6 months. The investigators also validated the IPQ in spanish. It was randomized 20 patients for the Lichtenstein repair and 20 patients for the Onstep technique. The study was conducted in the General Surgery Department of the Central Hospital Dr. Ignacio Morones Prieto, considered as a second level of attention and a surgery training center. The validated questionnaire in spanish and the visual pain scale were applied in the office at 1 week and by phone at 1 month, 3 and 6 months after surgery by two evaluators who did not know the surgical technique used.

The investigators use the Browne method to estimate the number of patients required for the study. It was applied simple randomization of 40 patients in two groups, the first one consists of 20 patients for the Lichtenstein repair and the second group of 20 patients for Onstep repair.

The Onstep procedure was performed by a surgeon skilled in the technique as described in the original article by Rosenberg and 3DMAXTM mesh by Bard was used. The technique is simple, the duration of the surgery is short and consists of a series of standardized steps. It combines an anterior with a preperitoneal approach, consisting of making a lateral incision to the rectus abdominis muscle and above the inguinal canal. It is dissected to a plane between the external and internal oblique fascia, the spermatic cord is dissected and sac reduction is performed, either directly or indirectly. The transversalis fascia is incised and the preperitoneal space is dissected. The mesh is preformed laterally to reinforce the deep inguinal ring and medially accommodates in the previously dissected preperitoneal space. The mesh was fixed to the Cooper's ligament, the pubic tubercle and the rectus abdominis muscle with 2-0 polypropylene suture.

The Lichtenstein technique was performed by different surgeons and regular polypropylene mesh was used.

The validated questionnaire in spanish and the visual pain scale were applied in the office at 1 week and by phone at 1 month, 3 and 6 months after surgery by two evaluators who did not know the surgical technique used. Statistical analysis of the results of the survey and visual pain scale in patients operated with the Onstep and Lichtenstein technique was performed with Student's t test and Fisher's exact test.

For the validation of the Inguinal Pain Questionnaire in our population the English-Spanish translation of the IPQ was carried out. Then the translation from Spanish to English was made by a person with English proficiency adjusting the initial translation. All postoperative patients with unilateral inguinal plasty, older than 16 years, with Lichtenstein or laparoscopic technique (TEP and TAPP), performed by different surgeons were included. The survey was applied in Spanish and numerical scale of pain to 21 patients who met the inclusion criteria, operated at the Central Hospital "Dr. Ignacio Morones Prieto", a week and a month after surgery. The first survey was conducted in the first week after surgery, the second was applied by telephone 4 weeks later, both performed by evaluators familiarized with the survey and unrelated to the knowledge of the surgical technique used. Analysis of the survey data was carried out using Cronbach's alpha for internal validation, re-test with the Spearman's rho to compare the variability of the responses with time and finally, the answers of the survey were compared with the score of the numerical scale of pain.

Inclusion Criteria:

• Diagnosis of unilateral inguinal hernia.
• Male or Female.
• Older tan 16 years.
• Accept to participate in the study.

Exclusion Criteria:

• Chronic Obstructive Pulmonary Disease.
• Obesity.
• Diabetes Mellitus.
• Cirrhosis.
• Diseases involving collagen deficiency.
• Previous surgery in the groin.