imageNew York—One in six patients who reported chronic pain six months after an open inguinal hernia repair still suffers from chronic pain 10 years later, according to a prospective German study reported at the Fifth International Hernia Congress. Others develop late-onset pain, even after five years.

“Patients reporting chronic pain vary with time. This is a very important message,” said lead author Wolfgang Reinpold, MD, director of the Department of surgery of Gross Sand Hospital and director of the Hernia Center, Hamburg, Germany.

The study was initially published in Annals of Surgery in 2011, at which point, only five-year data were available. At this spring’s international hernia meeting, Dr. Reinpold presented updated results after conducting a 10-year follow-up of the prospective two-phase study. The prospective cohort study followed 736 patients who underwent 781 elective primary inguinal hernia operations at the Hernia Centre of Reinbek Hospital, Germany, from April 2000 to April 2002. Patients underwent pain assessments on the day of surgery, the first, second and seventh day postsurgery, and at six months and five years after surgery.

The chronic pain was 16.4% and sensory disorder rate was 15.9% after six months. At the five-year mark, 16.1% of patients reported chronic pain and 20.3% had sensory disorder of the groin. Independent significant predictors of chronic pain were preoperative pain, chronic pain after six months, sensory disorder after five years and ilioinguinal nerve neurolysis in Lichtenstein repair due to mobilization of the nerve from its natural bed and nerve preservation.

Based on the results of the study, Dr. Reinpold and colleagues called on surgeons to avoid ilioinguinal nerve mobilization in the Lichtenstein technique. “The inguinal nerves should either be left untouched in their natural bed or if this is not possible a neurrectomy and proximal end implantation … should be performed,” they said.

At the meeting, the investigators presented their 10-year outcomes data. They had sent a questionnaire to 736 patients, and received responses from 55%. Eight patients in the cohort died over the course of the study.

Among the respondents, 13.6% reported chronic pain 10 years after surgery. Most patients with pain classified it as mild without an effect on daily activities or quality of life. However, eight patients (1.8%) had relevant pain, defined as a score greater than 3 on the visual analog scale. No patient described the sensation as very strong. Five of the eight reported a slight interference with daily activities.

Among the eight patients with relevant pain, five had undergone a Lichtenstein repair and three had a Shouldice repair. Seven of the eight patients had neurolysis of the ilioinguinal nerve with preservation of the nerve. Significant predictors of chronic pain were younger than age 50 years, sensory disorder of the groin after five years and chronic pain after six months.

Dr. Reinpold said the 10-year results confirm their earlier recommendations. They called on surgeons to visualize the nerves and handle with care; to leave the inguinal nerves untouched in their natural bed or, if this is not possible, to perform a neurectomy and proximal end implantation; to leave the cremasteric muscle and spermatic fascia in tact; and to avoid mesh suture fixation to the internal oblique muscle.

The investigators believe that a chronic inflammatory reaction occurs between the conventional polypropylene mesh and mobilized nerve, leading to long-term post-herniorrhaphy chronic pain. Another hypothesis is that chronic scar formation with fibrotic nerve traction leads to chronic pain.

Dr. Reinpold’s study comes on the heels of international guidelines published in 2011. Both reports stress what some specialists have argued for years: A mesh repair is not the same as a traditional tissue repair with the addition of mesh. Mesh repairs are a completely different operation and the nerves need to be treated carefully, left in their natural beds and not exposed to contact with the mesh.

“Mesh repair has its own principles that have to be followed. For many years, surgeons had a mindset that was otherwise,” said Parviz K. Amid, MD, clinical professor of surgery, David Geffen School of Medicine at University of California, Los Angeles and director of the Lichtenstein Amid Hernia Clinic at the university.

Dr. Amid said patients persistently hung onto three “cardinal mistakes from the past”: removing the ilioinguinal nerve from its natural bed, roughly mobilizing the spermatic cord by finger instead of doing it gently under direct vision and removing the cremasteric layers that protect the genital branch of the genitofemoral nerve and the vas deferens.

Based on the current evidence, the rate of chronic pain can be reduced to less than 1% by careful nerve handling, Dr. Amid said, and surgeons are growing more cognizant of nerve management. “Surgeons are beginning to understand that they have to deprogram their memory bank and not rely on teachings of the past,” said Dr. Amid.