My chest hurts – why wasn’t I told?
CHRONIC PAIN AFTER THORACOTOMY
W.A. Macrae
Ninewells Hospital, Dundee, United Kingdom
‘The postero-lateral thoracotomy produces one of the worst types of suffering that it is possible to inflict on patients. Failure to anticipate and manage it adequately is not only inhumane but the consequences of unrelieved severe post-operative pain are diverse and profound. To the long list of these consequences must be added post-thoracotomy neuralgia, for in some unfortunate individuals chest wall pain persists in a very severe and chronic form’ (Richardson et al. 1994).
The incidence of post thoracotomy pain varies according to studies, between 5-50%. In a careful series of studies by Richardson, Sabanathan and colleagues from Bradford in England, 1000 consecutive thoracotomies (883 suitable for analysis), were reviewed. They found a point prevalence of post-thoracotomy neuralgia of 22% at 2 months and 14% at 12 months (Richardson et al. 1994). The severity of the pain was variable, about 15% of patients having severe pain. Chronic post-thoracotomy pain is usually continuous, dating from the immediate post-operative period. Where pain appears after a pain-free period doubts should be raised as to its pathology. In their retrospective review of 238 patients Keller et al. (1994) found that worsening pain following an interval of good pain control occurred in 20 patients, all of whom were found to have tumour recurrence. The type of surgery, pathology and perioperative pain management may be risk factors. The evidence for the effect of surgical technique on pain following thoracotomy is contradictory with some papers showing a difference (Richardson et al. 1994), but others showing no long term difference (Landreneau et al. 1994). Two studies from Finland have shown that chronic pain is equally common after thoracotomy for malignant or benign disease (Perttunen et al. 1999, Kalso et al. 1992). However another study found that chronic pain was more common after surgery for benign oesophageal disease than for lung cancer (Richardson et al. 1994). Studies on the influence of acute post-operative pain on chronic pain are difficult, for many reasons. One of the only prospective studies found that early post-operative pain was the only factor that significantly predicted long-term pain (Katz et al. 1996).
Pain after surgery has many causes, as the work on mastectomy and thoracotomy shows (Polinsky 1994, Landreneau et al 1994). It is interesting and important to try and elucidate causes and risk factors because this allows us to look at strategies for prevention. This is particularly important because chronic pain after surgery is hard to treat effectively. Looking at simple local factors, for example type of surgery, infection, sternal wires etc, is an obvious first step, but we must take account of research which demonstrates the complexity of chronic pain problems. There are likely to be changes at the spinal cord and the brain as well as more peripheral changes (Besson 1999). To see the origin of these problems as lying in the mechanics of the surgery is to ignore the vital role played by plasticity within the nervous system. This has important implications for all of us, as it is possible that certain patients may be more likely to develop pain after surgery than others. There is evidence from animal work that genetic factors play a role in the development of chronic pain (Inbal et al 1980). It is also possible that certain concurrent medical conditions may predispose patients to chronic pain after surgery. The fact that separate studies show a fairly constant incidence of pain after thoracotomy or sternotomy, confirms that how the operation is done is not the only factor in the causation of chronic pain. This implies that the surgeon should not necessarily be blamed or even held responsible for the development of the chronic pain syndrome. It may not be a result of how the operation was done. It should be seen as a possible consequence of surgery in a certain proportion of patients. Doctors don’t feel guilty if a patient develops a side effect from a drug, and patients understand that side effects are an inevitable risk in taking drug therapy. If there was a change of attitude towards chronic pain after surgery, then the whole topic could be more openly discussed. Surgeons would be able to warn patients about the risks, and patients would understand that this was an inevitable risk of having surgery. This could prevent many angry confrontations at follow up!
In summary the high prevalence of both severe and relatively mild (though not inconsequential) pain requires attention. There is a suggestion from some studies that the operative approach, perioperative care and level of immediate post-operative pain may all have a bearing on the subsequent development of a chronic pain problem. If this is true it holds out hope for prevention. However, the quality of the existing studies is inadequate to support the inferential demands made of them. Better quality studies (preferably prospective and randomised, but also well-conducted, properly adjusted cohort analyses) are needed to test existing hypotheses and develop preventative strategies.
Time of Presentation
Sunday 14 May 2006 - 1030-1200
References
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