A questionnaire study investigating the prevalence of chronic postoperative pain

Chronic postoperative pain (CPOP) is defined as pain of at least 2 months duration after a surgical procedure. Until recently, it has been a neglected topic, because it can occur after a wide spectrum of operations; however, little is known regarding its underlying mechanism, prevalence, risk factors, and treatments. We investigated characteristics of CPOP after various operations via a questionnaire. Patients were contacted at > 2 months after surgery, irrespective of sex, type of operation or anesthesia method, and a follow-up pain questionnaire was administered by phone. One hundred forty-five of 400 patients (36.3%) described CPOP. The prevalence of CPOP was significantly lower in laparoscopic surgery (29/159, 18.2%) than open surgery (116/241, 48.1%). The prevalence of CPOP was higher with the use of PCA (patient controlled analgesia), (45.3%) than without PCA (24.6%). There were no significant differences regarding sex, anesthetic method, or duration of operation. Our results indicate that the prevalence of CPOP may be related to use of an endoscope and PCA. However, it is difficult to completely explain the correlation, because this is a complex area of research. More research is needed to improve the quality of pain relief.