Faced with a man with leg amputation and asked what his problem may be, most of us
would probably leap to the conclusion that he had phantom limb pain, because that is
what we have been conditioned to expect. What is less expected is that chronic pain
is a possible, if often overlooked, adverse outcome of surgery. A systematic review
[1] has examined the incidence of chronic pain after surgery and suggests that it is
very common.
Review
The review searched OVID to January 1999 for articles linking persistent pain to
surgery. Authors' databases and references were also examined. For inclusion articles
had to have information about pain 12 weeks or longer after surgery. Generally,
studies smaller than 50-100 patients were excluded, apart from amputation studies
where studies with 25 patients were accepted.
Results
Chronic pain after surgery was common. Many studies had information to one year or
longer, and many compared different surgical approaches, or anaesthesia. The results
shown in Figure 1 use data from studies closest to one year after surgery, and
combine surgical approaches when reported separately. Where several types of chronic
pain were reported (like chest pain, arm pain, or phantom breast for breast surgery),
the pain at or close to the site of operation was taken. The figures for breast pain
include mastectomy, lumpectomy, breast augmentation and reduction.
Figure 1: Chronic pain after surgery, at about 1 year
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Phantom limb pain was common, but high rates of chronic pain were reported for
all surgery. Even in the lowest incidence, hernia repair, rates varied from 0% to
29%.
Predictive factors included pre-operative pain, repeat surgery, a surgical
approach with risk of nerve damage, acute and severe post-operative pain,
radiation, chemotherapy and a variety of psychological and depressive symptoms.
Functional impairment
More than 95% of all hernia operations performed in Denmark are reported to the
Danish Hernia Database. In a two-month period in 1998 1,652 patients had surgery
for inguinal or femoral hernia, and 1,443 questionnaires were mailed one year
after surgery. The first questionnaire established the incidence of pain, and the
second characterised the pain and its effect on function.
Results
There was an 81% response to the first questionnaire. Twenty-nine percent
reported having pain in the area of the hernia within the past month, and 11%
reported that the pain impaired work or leisure activities. Only 4.5% (1 in 6)
had sought medical advice or received treatment for the pain.
Comment
How much pain there is, and its location and nature, determine how important is
chronic pain after surgery. Even the lowest figure of 1 in 20 patients needing
treatment or advice for pain one year after surgery has large resource
implications. Postoperative breast pain occurred not just after mastectomy, but
after lumpectomy, and after breast augmentation and reduction, which are elective
procedures.
Two issues emerge. The obvious one is to find out more about what influences the
incidence of chronic pain after surgery, and do something about it. The other is
to make patients aware that surgery can have longer-term consequences.
References:
- FM Perkins, H Kehlet. Chronic pain as an outcome of surgery: a review of
predictive factors. Anesthesiology 2000 93: 1123-1133.
- M Bay-Nielsen et al. Pain and functional impairment 1 year after inguinal
herniorrhaphy: a nationwide questionnaire study. Annals of Surgery 2001 233:
1-7.
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