No abstract

The frequency of chronic pain after inguinal hernia repair was found to be as high as 54%, much more than previously reported. Quality of life of these patients is affected. Chronic pain is reported less often after laparoscopic and mesh repairs. Recurrent hernia repair, preoperative pain, day case surgery, delayed onset of symptoms, and high pain scores in the first week after surgery, however, were identified to be risk factors for the development of chronic pain. Definition of chronic pain was not explicit in the majority of the reviewed studies. Accurate evaluation of the frequency of chronic pain will require standardization of definition and methods of assessment. Prospective studies are required to define the role of risk factors identified in this review.

Comparison of the epidemiology of 'significant chronic pain' and 'severe chronic pain' with 'any chronic pain' allows an understanding of the more clinically important end of the chronic pain spectrum. These results support the suggestion that chronic pain is multidimensional, both in its aetiology and in its effects, particularly at this end of the spectrum. This must be addressed in management and in further research.

Little is known about the course of chronic pain in the community. Such information is needed for the prevention and management of chronic pain. We undertook a 4-year follow-up study of 2184 individuals living in Grampian, UK to describe patterns and predictors of change in chronic pain over time. In October 2000, participants completed a postal questionnaire including case definition questions, the chronic pain grade questionnaire, the SF-36 and socio-demographic questions. Information from this questionnaire was compared to information collected from a similar questionnaire in 1996. A response rate of 83% was achieved for the follow-up study. The overall prevalence of chronic pain (pain or discomfort present either all the time or on and off for 3 months or longer) increased from 45.5% at baseline to 53.8% at follow-up. Seventy-nine percent of those with chronic pain at baseline still had it at follow-up. The average annual incidence was 8.3% and the average annual recovery rate was 5.4%. Individuals in the study samples who are in lowest quartile of SF-36 domains--physical functioning, social functioning and bodily pain at baseline--were more likely to develop chronic pain at follow-up, and respondents who were retired were less likely to develop chronic pain. Individuals in the study samples in the lowest quartile of SF-36 domains, bodily pain and general health at baseline, were less likely to recover from their chronic pain, as were those aged 45-74 compared with those aged 25-34. We concluded that chronic pain is a common, persistent problem in the community with relatively high incidence and low recovery rates. The lack of association between onset or recovery from chronic pain and most traditional socio-demographic factors, highlights the need to broaden the range of factors included in studies of chronic pain aetiology.

Chronic pain occurred in 30 per cent of patients after open hernia repair, a higher frequency than has been reported previously. Several risk factors were identified and further prospective research is recommended.