Prevention of inguinodynia: the need for continuous refinement and quality improvement in inguinal hernia repair.

Dear Editors, It was with great interest that we read the manuscript Mesh fixation at laparoscopic inguinal hernia repair: a meta-analysis comparing fibrin glue to tack fixation [1]. While there have been several studies, randomized controlled trials (RCTs), reviews, and meta-analyses comparing these fixation methods, the authors have provided a methodologically sound analysis of the available studies to date, commendably choosing to focus on the outcome of chronic pain. The success of modern herniorrhaphy techniques and the use of prosthetic materials have dramatically reduced recurrence rates, and chronic pain exceeds recurrence as the more frequent complication. Quality of life and avoidance of chronic pain have become important metrics of successful surgery. Inguinodynia has been a recognized complication with all techniques of hernia repair and long preceded meshbased techniques. [2, 3] While there is a statistical advantage of laparoscopic repair with regards to acute pain, direct comparisons between open and laparoscopic repair regarding chronic pain are difficult because the definitions and technique vary amongst studies. The wide variation is apparent, even within this meta-analysis of laparoscopic repairs where the five included trials report rates of chronic pain ranging from 0 to 24 % [1]. The recently published 2014 update to the European Hernia Society (EHS) guidelines reaffirms that there is no difference in the incidence of significant chronic pain between open and laparoscopic repair. [4] Remedial surgery for neuropathic inguinodynia after preperitoneal repair is more challenging than with anterior repair and requires proximal access to these nerves via retroperitoneal neurectomy. [5–7] Proper technique and respect for neuroanatomy with each chosen method of repair is critical to improving outcomes and preventing inguinodynia. The important developments by Nyhus, Read, Stoppa, Wantz, Rives, Shumpelick, and others have helped to define and utilize the preperitoneal anatomy for effective hernia repairs. Laparoscopic totally extraperitoneal (TEP) and transabdominal preperitoneal (TAPP) approaches have made this compartmental anatomy ubiquitous for most hernia surgeons. However, in-depth understanding of the neuroanatomy of this compartment is needed to prevent neuralgia, orchialgia, dysejaculation, recurrence, and meshoma. [8] Causes of chronic pain can be nociceptive or neuropathic in origin and there is often overlap between the two, making diagnosis and treatment challenging. The most common causative mechanisms with laparoscopic inguinal hernia repair include neuropathy from direct contact with mesh, meshoma pain from folding of the mesh, and direct nerve injury (dissection, thermal injury, fixation). [5, 6] Read [9] and Mirilas et al. [10] have helped to delineate the surgical anatomy of the preperitoneal space, confirming the presence of two compartments behind the transversalis fascia separated by a membranous layer. [8–10] The visceral compartment medially contains the bladder, ureter, and prostate and laterally contains the vas deferens ensheathed by this membranous layer. The parietal compartment contains the genitofemoral trunk and its genital and femoral branches and the lateral femoral cutaneous nerve within the classically described ‘trapezoid of pain’. The ilioinguinal and iliohypogastric nerves travel in the retroperitoneum and exit cephalad and lateral to most preperitoneal repairs. [7, 10] Unlike the nerves in the D. C. Chen P. K. Amid (&) Department of Surgery, Lichtenstein Amid Hernia Clinic at UCLA, UCLA David Geffen School of Medicine, Santa Monica, CA, USA e-mail: pamid@mednet.ucla.edu