International Association for the Study of Pain: ‘Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage’ (Merskey & Bogduk 1994, pp. 209–214). Pain is also regarded as a personal and subjective experience that should be evaluated by patients themselves whenever possible (McCaffery & Pacero 2001).
Postoperative pain is an expected outcome for patients after surgical procedures and it impairs organ functions, delays mobilization and overall recovery as well as increasing the risk of postoperative complications (Kehlet 1997, Breivik 1998, Carr & Goudas 1999, Coll et al. 2004a). Nonetheless there is long-standing evidence of inadequate pain relief, in spite of increasing treatment options (Bostro¨m et al. 1997, Watt-Watson et al. 2000). Mild pain seems to be common following radical retropubic prostatectomy (Sall et al. 1997, Dalpra & Zampieron 1998, Haythornthwaite et al. 1998).
It seems that people are prepared to accept postoperative pain (Wulf et al. 1998, Dawson et al. 2001, Leinonen et al. 2001). Also, after prostatectomy, patients are very satisfied or satisfied with their postoperative pain care, and such a curative operation affects feelings and pain tolerance (Klein et al. 1996, Worwag & Chodak 1998). Affective distress, particularly anxiety before surgery, and the use of pain medication afterwards, may be predictors of chronic pain following prostatectomy (Haythornthwaite et al. 1998).
Pain assessment is the first step towards adequate pain relief. It has two major problems: first, the subjective nature of the pain experience; and second, the lack of quantifiable measurements (McGuire 1992, Watt-Watson et al. 2000). Most prostatectomy patients are old, and as such may need more time to assess their pain (Simons & Malabar 1995, Melzack & Wall 1996). Older patients may receive more attention and pain interventions than younger patients, and evidence suggests that men might be given more medication than women (Simons & Malabar 1995, Yorke et al. 2004).
Information and other support may help patients evaluate their experiences of pain, but the main difficulty is that different people respond to pain in different ways. Hence, direct comparisons are therefore impossible, even where the underlying cause of pain is the same. Verbal assessments may also be misinterpreted (McGuire 1992, Ferguson et al. 1997).
Pain measurement tools
The use of a simple, valid and reliable pain assessment tool in the clinical practice would standardize assessment and contribute to more effective management and evaluation of pain (Taylor 1997). The most common tools are the visual analogue scale (VAS) and 0–10 numeric rating scale (NRS) (Jensen et al. 1986, Carpenter & Brockopp 1995, Coll et al. 2004b), as well as the verbal rating scale (VRS) or verbal descriptor scale (VDS) (Bondestam et al. 1987). The quantitative analysis of the results from these scales is problematic, because it yields a classification where pain is slotted into given categories that are defined in advance. However, the boundary lines between the different categories have not been verified, which complicates the task of interpreting the results (Chapman et al. 1985, Bondestam et al. 1987).