Sometimes a patient will complain of apparently inexplicable postoperative pain, even if he has been treated in the same manner as other patients reporting no postoperative pain. Do all patients have the same risk to develop postoperative pain? Aasvang et al. [1] designed a novel prospective study that had the primary end point of assessing the relative contribution of preoperative, intraoperative, and postoperative factors in the development of persistent postoperative pain (PPP) substantially affecting everyday activities after groin hernia repair. The authors found four factors to be independently correlated to PPP-related impairment: preoperative Activity Assessment Scale (AAS) score, preoperative pain response to heat, intraoperative nerve injury, and early (day 30) postoperative pain intensity. A randomized study by Singh et al. [2] showed that preoperative pain, younger age, open surgery, and 7-day postoperative pain were independent risk factors for chronic pain. In other studies [3, 4] age has again been found to be an independent factor for postoperative pain.

So how should we treat a painful hernia in a young man? All surgeons should choose the operative technique that they know best, is safest in their own hands, and therefore will have the lowest individual risk of postoperative pain. Moreover, looking at our experience, groin pain with a small bulge of posterior inguinal wall is often incorrectly labeled a hernia; however, a proper physical examination and clinical history investigation reveal all the features of the so-called pubic inguinal pain syndrome (PIPS) [5]. Pain in PIPS is usually well localized and tends to be focused on the pubic bone with radiation superiorly to the abdominal rectus insertion and inferiorly to the adductor longus insertion. The site of pain is typically provoked by athletic activities such as kicking, sprinting, and changing directions; the symptoms usually persist the day after; they improve after resting and recur if athletic activities are resumed. Physical examination reveals tenderness or pain over the pubic crest on resisted sit-up (“abdominal crunch test”). Palpation of the internal ring can be painful and a small bulge of the inguinal posterior wall can be detected during coughing, but a palpable lump indicating a classical inguinal hernia is absent. During the adductor test, patients feel a sharp pain in the groin [6].

For these reasons, surgery intended to treat this subset of pain should not be limited to addressing the posterior wall. In order to maximize the chance of relieving preoperative pain, release of the three inguinal nerves in the region and tenotomy of the rectus abdominus rectus and adductor longus should be included.

Several randomized studies have compared local anesthesia with general and/or regional anesthesia. They confirm the advantages of local anesthetic, including less postoperative pain [7–13]. For these reasons, it is the favored anesthesia in centers specializing in hernia surgery [14–17]. The administration is technically quite easy but requires training and is successful only if the surgeon handles the tissues gently, has patience, and is competent and facile with the technique. Local anesthesia should be the first option for inguinal hernia repair in the adult, but sedation or general anesthesia with short-acting agents and combined with local infiltration anesthesia may be a valid alternative to local anesthesia alone for surgeons in training or outside of specialized hernia centers [17].

In order to decrease the amount of dissection in the inguinal canal, the manipulation of the inguinal nerves [18], and the interaction between the foreign material of the mesh and the spermatic cord and nerves, placement of the mesh in the preperitoneal space is an option to be considered [19]. By placing the mesh in the preperitoneal space, a more physiologic location for the mesh with intra-abdominal forces on one side and the oblique muscles on the other, fixation becomes less mandatory although may not be completely abandoned [19].

Usher et al. [20] introduced the prosthetic preperitoneal repair performed through an anterior approach using polyethylene mesh (later polypropylene), which was not slit because the spermatic cord was lateralized. Mahorner and Goss [21] used anterior preperitoneal grafts to support the overlying weakened transversalis fascia in two patients with recurrent herniation and destruction of both Poupart’s and Cooper’s ligaments. Rives [22] pioneered both anterior and posterior preperitoneal prosthetic repairs of groin hernias in France using Mersilene mesh. More recently Kugel (1999) employed this approach through an abdominal gridiron incision, using a fortified patch to reinforce the overlying damaged transversalis fascial floor of the inguinal and femoral canals [23].

With regard to prosthetic preperitoneal repair through a posterior approach, the precursor to modern laparoscopic techniques [totally extraperitoneal repair (TEP), transabdominal preperitoneal repair (TAPP), enhanced or extended view TEP (eTEP)], Stoppa et al. [24] reported on the giant prosthetic reinforcement of the visceral sac (GPRVS) in 1965. Large bilateral Dacron meshes were inserted deep into the weakened transversalis fascia, covering Fruchaud’s myopectineal orifice with extensive overlap. This operation provided an alternative to the anterior preperitoneal approach, which, in cases of recurrent herniation, encounters scarring possibly leading to damage of the spermatic cord, nerves, and blood vessels. Wantz [25] proposed a unilateral version of this operation, reaching the preperitoneal spaces of Bogros and Retzius using a transverse incision extending laterally 9 cm from the linea alba and 3 cm below the anterior superior iliac spine.

Gilbert [26] developed a two-layered prosthesis; the superficial portion rests on the transversalis fascial floor of the inguinal canal, while the lower portion lays beneath in the anterior preperitoneal space. The patches were connected by a plug that passed through the internal inguinal ring. A slit in the onlay portion allowed for passage of the spermatic cord to the inguinal canal below the external oblique aponeurosis. Widespread release of the device from its manufacturer (1998) led to the technique being called the Prolene Hernia System (PHS).

More recently the transinguinal preperitoneal repair (TIPP) technique had been proposed by Pellisier [27]: this technique involves a standard anterior approach through the inguinal canal where a patch with a memory ring is placed into the preperitoneal space behind the transversalis fascia. Willaert et al. [19] recently proposed with the Cochrane collaboration a review with the aim to compare the efficacy of an elective open preperitoneal mesh repair via either anterior or posterior approach with the Lichtenstein technique . Efficacy was considered as the absence of chronic pain after at least three months of follow-up. All published and unpublished randomized controlled trials (RCTs) comparing any elective open preperitoneal mesh technique with Lichtenstein repair were considered for inclusion. Strangulated inguinal hernias, bilateral inguinal hernias, and recurrent inguinal hernias were exclusion criteria.

Unfortunately, many studies did not address the primary outcome of the review and only three studies were included. In these three trials, the Lichtenstein technique was compared with Read-Rives technique [28], TIPP [19], and Kugel patch [29]. The last two studies reported less chronic pain after preperitoneal repair; however, the Muldoon study described slightly more chronic pain after preperitoneal repair. Few data are present in the literature about chronic pain after Wantz posterior preperitoneal repair: this technique is usually used in the specialized hernia center for the treatment of very large, incarcerated hernias, recurrent hernias, femoral hernias, or in the treatment of postoperative chronic pain [30].

As previously mentioned, intraoperative nerve injury has been shown to correlate independently with postoperative pain-related impairment [1]. Damage to, or entrapment of, one or more of the three inguinal nerves passing through the operative field may cause neuropathic pain. It is not always possible to follow traditional teaching dictating that every effort should be made to identify, preserve, and prevent traumatization or interruption of the inguinal nerves during operation. Inguinal nerves might interfere with placement of mesh or might be traumatized inadvertently during the operation. Several patterns of nerve injury during elective inguinal hernia repair have been described, including inadvertent suture entrapment, partial division, crushing, diathermy burn, or scar encroachment [31]. Identification and routine excision or division of selected inguinal nerves, termed “pragmatic neurectomy ,” during inguinal hernia repair has been proposed as a method for avoiding postoperative neuralgia [32].

Overall, the systematic review and meta-analysis proposed by Hsu et al. [33], including six RCT studies, indicate that preserving the ilioinguinal nerve during open mesh repair of an inguinal hernia was associated with decreased incidence of sensory loss at 6 and 12 months postoperatively compared with nerve division technique. They found no difference between the two surgical procedures in regard to the occurrence of chronic groin pain or numbness. In the 2014 update of the European Hernia Society Guidelines for the treatment of inguinal hernia in adults [34], all studies with the longest follow-up interval were combined in a new meta-analysis, and they concluded that routine prophylactic resection of the ilioinguinal nerve is not recommended (Grade A). It remains speculative whether this approach would be beneficial in a subset of patients with preoperative risk factors for chronic pain [34].

Importantly, five of the six studies included in the meta-analysis compared the effects of nerve preservation and of prophylactic neurotomy for just the ilioinguinal nerve, ignoring that all three nerves contribute to the sensory innervation of the groin.

Only the study reported by Karakayali et al. [35] focuses on the additional role of the iliohypogastric nerve: in this study patients had been divided into a nerve preservation group, ilioinguinal neurectomy group, iliohypogastric neurectomy group, and a group in which both nerves were transected. The only significant difference between the groups for chronic groin pain at the 1-year postoperative follow-up was between the nerve preservation group and the dual nerve transection group, in favor of the latter.

The majority of surgeons do not routinely detect all three inguinal nerves: the identification of the iliohypogastric nerve ranges between 32 % [36] and 97.5 % [37] of cases and for the genital branch of the genitofemoral nerves ranges between 21.3 % [37] and 36 % [36] of cases. An Italian prospective multicenter study [38] of 973 cases and a French single center study [39] of 1332 cases are the only two published studies reporting the results of the role of the identification of all three inguinal nerves (2305 cases all together) with a long follow-up period (ranging from 1 to 5 years). Both studies concluded that identification and preservation of all three inguinal nerves during open inguinal hernia repairs reduce chronic incapacitating groin pain to less than 1 %: the mean incidence of chronic pain was 0.8 % (range 0–1.6 %). The Italian study [38] also demonstrated that the risk of developing inguinal chronic pain increased with the number of nerves concomitantly undetected. Likewise, the division of nerves was correlated strongly with the presence of chronic pain.