Left inguinal region during surgery for the treatment of chronic postoperative pain: isolation of the previously placed mesh and identification of a running fixation suture along the inguinal ligament; the suture also involves the genital branch of genitofemoral nerve.
A multicenter RCT  has suggested that fibrin sealant may have a beneficial effect in chronic pain. In the recent systematic review proposed by Sanders , twelve trials comparing n-butyl-2 cyanoacrylate (NB2C) glues to sutures, self-fixing meshes to sutures, fibrin sealant to sutures, tacks to sutures and absorbable sutures to non-absorbable sutures were included. Although there was no significant difference in recurrence or surgical site infection rates between fixation methods, there is insufficient evidence to promote fibrin sealant, self-fixing meshes or NB2C glues ahead of suture fixation.
Although several studies [44–52] have compared the type of fixation in the laparoscopic approach (none vs. atraumatic vs. resorbable or non-resorbable fixation devices), the analysis is seriously flawed by different factors such as the way chronic pain is evaluated and the many independent variables (the type of repair, the type of hernia, the type of mesh and the type, number and location of the fixation devices). Thus recommendations from the European guidelines are that, when using heavyweight meshes, traumatic mesh fixation in TEP endoscopic repair should be avoided (with the exception of some cases such as large direct hernias). Atraumatic mesh fixation in TAPP endoscopic repair can be used without increasing the recurrence rate at 1 year.
16.6 16.6 Treatment
Data in the literature are poor and inconsistent due to limited information on preoperative demographics, differences in definition and evaluation of pain degree and limited follow-up, so comparison among different strategies and their results is very difficult.
Initial acute postoperative pain treatment should be as effective as possible and standard pharmacological pain treatment (gabapentanoids, tricyclics, etc.)  for neuropathic pain should be instituted earlier in patients with severe pain. The question of whether this may reduce development of chronic pain is debatable in the absence of any conclusive data . The working group of the international guidelines for prevention and management of postoperative chronic pain following inguinal hernia repair decided to consider reasonable surgical treatment only after 1 year postoperatively, when the inflammatory response has decreased, and only when pain intensity curtails activity and conventional treatment has failed (level of evidence 5, grade of recommendation “D”) .
It has been proved that analgesic patches [lidocaine patch (5%) and capsaicin (8%)] do not reduce summed pain intensity (at rest, during movement, and during pressure) .
Nerve infiltration with anesthetics is a minimally invasive technique for treating peripheral neuropathy after inguinal surgery [56, 57]. Varying success rates have been reported, but the relative ease of application is a main advantage [58, 59]. Several studies [60–68] reported the use of diagnostic blocks presurgery. The use of ultrasound-guided regional anesthesia has increased in the last decade and enables direct visualization of peripheral nerves, facilitating the success rate of the blocks . As a result, there is no scientific evidence of any short-term or long-term analgesic efficacy of local anesthetic blocks in persistent postsurgical pain (PPP) following inguinal hernia repair. However, the potential for local anesthetic blocks in predicting surgical outcome should be considered, particularly in excision of painful neuromas : e.g., if a diagnostic nerve block is ineffective in relieving pain, patients will most likely not benefit from surgical treatment.
Several different techniques of neuromodulation have been proposed. Pulsed radiofrequency (PRF) is an invasive pain treatment technique that employs electromagnetic energy deposited in or near nerve tissue [70, 71]. An insulated needle with an active tip is inserted at the vertebral level or at the peripheral level. Paresthesias are then elicited in the painful area, by electrical stimulation as an indication of adequate positioning of the needle tip. The voltage applied to the treatment needle is rapidly raised and lowered, with voltages typically alternating between 0 and 40 V with a frequency of 300–500 kHz. The temperature is held below 42°C avoiding structural damage to the nerve tissue. The moderate heating of the nerve tissue is believed to temporarily block the nerve conduction.
Conventional continuous radiofrequency (CRF) produces temperatures at the tip of the treatment needle of 45–80°C leading to irreversible thermo-coagulation of nerve structures and has proven considerably more efficacious than PRF in various chronic pain states . A recent retrospective uncontrolled study reported a longer duration of pain relief in the CRF group than in the local anesthetic block group at 12-month follow-up .
Peripheral nerve stimulation utilizing a transperitoneal laparoscopic approach with selective implantation of quadripolar electrodes at the genitofemoral nerve (anterior surface psoas major muscle) or ilioinguinal nerve, iliohypogastric nerve and femoro-cutaneous lateral nerve (anterior surface quadratus lumborum muscle) has recently been presented with promising results .
Although preliminary reports with neuromodulation techniques are enthusiastic and promising, the evidence is still of low quality, and the strength of recommendation is weak to moderate . The scientific rigor is generally not considered adequate and study designs should be improved in regard to control groups, randomization, blinding procedures, and adequate sampling sizes .
Werner  reported a comprehensive review of 25 studies [2, 60–66, 75–89] in the surgical management of PPP following inguinal hernia repair. Most of the studies reported an open surgical approach, few a laparoscopic approach and only three studies reported a combined approach. All studies included neurectomy and comprise selective neurectomy, triple neurectomy or extended neurectomy. Removal of the mesh, either complete or partial, was performed in 11 studies and a new mesh was placed in five studies. Consistently satisfactory results in the majority of patients were reported.
With regard to follow-up, it is important to remember that nerve transection is known be associated with delayed onset of neuropathic pain symptoms, from months to years, so extended follow-up times are suggested .
In spite of these shortcomings, the data on surgical management clearly demonstrate that neurectomy with or without mesh removal may provide long-lasting analgesic effects in most patients with severe PPP following inguinal hernia repair.
The authors propose a total simultaneous double approach to the inguinal region: first, by a posterior-preperitoneal approach we identify and cut all the sensitive nerves, and safely remove the plug (if any) placed during previous surgery and then, by an anterior approach through the same incision, we remove the mesh and fixation stitches placed during previous surgery. A new repair is done with an ultralight or biological mesh in the preperitoneal space fixed with glue .
We always perform a triple neurectomy as it is extremely difficult, if not impossible, to pinpoint the involved nerve because peripheral communication between the ilioinguinal, iliohypogastric, and genital branch of the genital femoral nerve is very common and results in an overlap of their sensory innervation. The preperitoneal approach allows us to identify the three nerves in a virgin field without scarring. Finally, we always remove the previously placed mesh because the real reason for pain (neuropathic or non-neuropathic) cannot be detected.
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