Chronic pain tackled by surgeons at world hernia meeting
Nowadays, chronic groin pain post surgery for hernia presents as one of the most important issues for the inguinal hernia patients and the treating surgeons. However, the etiology and prevention of this chronic pain stands uncertain.
Recent studies on pain estimation have shown that moderate to severe chronic pain occurs after inguinal hernia repair in approximately 10%-12% of the patients, while severe chronic pain affecting day to day activities occurs in only 0.5%-6% of the patients (J Pain Res2014;7:277-290).
At the World Hernia Conference held in Milan, pain landscape was the point of discussion of the attending surgeons, and span from current insights and gaps in the current knowledge of pain to potential treatments as well as preventive measures.
Dr. Gerard Champault, MD, a general surgeon from France, summarized his opinion on pain related to inguinal hernia repair. After studying the relevant literature, he reported that overall studies concluded lesser pain with laparoscopic repair, mesh repair, and lightweight mesh when compared to open repair, non-mesh repair, and heavy mesh, respectively. However, the findings were limited to short-term studies.
Dr. Kevin Petersen, MD, a general surgeon practicing in Las Vegas, shared his experience with mesh and chronic pain. He informed that after surgeons began rapidly shifting from pure tissue to mesh repairs in the mid-1990s, cases of patients with mesh-related pain started appearing in the clinic. Dr. Petersen also discussed specific cases related to mesh related pain involving loss of work productivity and disability. Results of 114 mesh explants performed on patients with chronic pain over the past six years were presented by Dr. Petersen. Different types of laparoscopic and open procedures with mesh to heal inguinal hernias (82%) as well as umbilical, incisional, femoral and epigastric repairs were performed on these patients.
A formal laparotomy for mesh removal was performed by Dr. Petersen and in cases where required an existing hernia was repaired using modified McVay technique. After mesh explants, there were minimal complications and included two wound infections along with eight hernia recurrences.
Average pain score on a 10-point visual analog scale before surgery (8.2) and in the two years after surgery (2.7) improved significantly. Majority of the patients had significant relief while one third of the patients did not achieve much benefit.
The reason for the pain was not clear particularly in the patients whose pain did not improve after conducting mesh explant. Dr. Petersen reported that some patients have mesh migrations and meshoma but in most cases, he did not find any technical problems in the mesh implant or the surgical method. He also insisted that disturbing or irritating nerves in the groin can cause pain after inguinal hernia repair.
David Chen, MD, FACS, assistant clinical professor at UCLA Lichtenstein Amid Hernia Clinic, David Geffen School of Medicine at the University of California, Los Angeles also had same opinion on disturbing nerves as the cause of pain. Dr. Chen and his colleagues in their 2014 study explained many ways in which nerves can be damaged after inguinal repair, including surgical manipulation, stretching, crushing, partial or complete transaction, or entrapment in a suture or tacks.
During the expert hot topic discussion at hernia meeting on mesh fixation in laparoscopic inguinal hernia repair, Matthew Goldblatt, MD, general surgeon underlined a prospective multicenter study (Surg Endosc 2008;22:757-762) that monitored 360 patients who had fixation with metal tacks or no fixation during laparoscopic totally extraperitoneal (TEP) hernia repair and the investigators found that patients who had fixation were in more pain after 6 to 13 months of surgery and patients with bilateral repairs were five times more likely to report more discomfort on the fixated side.
Dr. Goldblatt also talked about the study (World J Surg 2013;37:1249-1257) which compared the quality of life after TEP, transabdominal preperitoneal (known as TAPP) or modified Lichtenstein repairs, and described that the occurrence of early postsurgical pain increases if 10 tacks or more are used but do not affect relapse of chronic postsurgical pain.
Chronic pain after inguinal hernia repair can be due to postsurgical fibrosis (World J Gastroenterol 2011;17:1791-1796) which is nothing but scarring or the formation of excessive connective tissue in an organ or tissue typically in response to an injury and occurs as regular healing process but excess of scarring can alter the design of an organ resulting in inhibition of mesh integration and causes pain.
At the meeting, Yuri Novitsky, MD, professor of surgery and director of the Case Comprehensive Hernia Center at Case Western Reserve University, in Cleveland, discovered the association between fibrosis and biocompatibility of mesh. He mentioned that according to a study conducted in 2012, synthetic mesh, macroporous polyester mesh implanted in mice resulted in the greatest foreign body reaction and chronic inflammatory response, with expanded polytetrafluoroethylene (ePTFE) also producing a strong fibrosis response, and macroporous, reduced-weight polypropylene mesh exhibiting the best biocompatibility as shown in 2012 study (J Surg Res 2012;176:423-429).
Dr. Chen expounded that experience of surgeon may play a vital role in chronic pain after hernia repair and most of the surgeons do not perform a sufficiently large volume of hernia repairs to gain expertise at it. Pain is complex and patients’ psychological, anatomic and genetic variations, as well as surgical factors also impacts pain.
Dr. Champault suggested that perioperative cooling of the surgical site can reduce early or short term pain (Pain Studies and Treatment 2014;2:113-120) while other options to manage post-surgical pain include spinal cord stimulation, neurostimulation and triple neurectomy, but no method works in all patients.