Inguinodynia

Post herniorrhaphy pain syndrome, or inguinodynia is pain or discomfort lasting greater than 3 months after surgery of inguinal hernia. Randomized trials of laparoscopic vs open inguinal hernia repair have demonstrated similar recurrence rates with the use of mesh and have identified that chronic groin pain (>10%) surpasses recurrence (<2%) and is an important measure of success.

Chronic groin pain is potentially disabling with neuralgia, parasthesia, hypoesthesia, and hyperesthesia. Patients may be unable to work, have limited physical & social activities, sleep disturbances, and psychologic distress. The management of inguinodynia is a difficult problem for many surgeons and 5–7% of patients experiencing post-hernia repair groin pain litigate.

The true incidence is difficult to determine, pain having a subjective component. A prospective series of open Lichtenstein (419 patients) noted that at 1 year followup, 19% of patients had pain, 6% with moderate or severe degree. Predictors of moderate or severe pain included: recurrent hernia, high pain score at 1 week postop, and high pain score at 4 weeks postop.

A Scottish population based study of 4062 patients identified at 3 months postop an incidence of 43% mild pain and 3% severe or very severe pain. The severe and very severe group was associated with young age and female gender. A further survey of the 3% severe pain cohort (at a median of 30 months) found that 29% resolved, 39% improved and 26% continued with severe, or very severe pain.

A followup of a randomized study of 750 laparoscopic vs. open hernia repair followed patients’ pain scores at 2 and 5 years post hernia repair via questionnaire. At 2 years, the chronic pain rate was 24.3% (lap) vs. 29.4% (open), and at 5 year follow up it was 18.1% (lap) vs. 20.1% (open). At 5 years, 4.3% in lap group and 3.7% in open group had attended a pain clinic.

A larger and more recent study which was a followup at 5 years of 1370 from a randomized study of TEP vs. open repair demonstrated lower pain rates in the laparoscopic group (10% vs. 20%). Inguinodynia symptoms decreased over time, even in those in the moderate to severe pain group. In addition, when an inguinal pain questionnaire was administered to these individuals at a median followup of 9.4 years, physical ability was affected more in the open repair group. Predictors of chronic pain in the TEP group included Body Mass Index ≤ 3rd quartile (OR: 3.04), difference in preop and postop physical testing (OR: 2.14) and time to full recovery exceeding the median (OR: 2.09). In the open group, the only association was noted with postoperative pain score exceeding the third quartile (OR: 1.89 ).

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