Use of a lidocaine patch in the management of postsurgical neuropathic pain in patients with cancer: a phase III double-blind crossover study (N01CB)
Postthoracotomy pain syndrome is relatively common and is seen in approximately 50% of patients after thoracotomy. It is a chronic condition, and about 30% of patients might still experience pain 4 to 5 years after surgery. In the majority of patients pain is usually mild and only slightly or moderately interferes with normal daily living. In a small subset of patients pain can be severe and can be described as a true disability to the extent that these patients are incapacitated. The exact mechanism for the pathogenesis of PTPS is still not clear, but cumulative evidence suggests that it is a combination of neuropathic and nonneuropathic (myofascial) pain. Trauma to the intercostal nerve during thoracotomy is the most likely cause. Because pain does not cause disability in the majority of patients, management is usually conservative. If pain is causing disability then multidisciplinary pain management involving the pain specialist, social worker, physical therapist, and a psychologist is required. It is mandatory to exclude recurrence of disease or malignancy as a cause for the pain prior to initiating treatment. As with most forms of neuropathic pain, treatment of PTPS is also difficult and patients might require more than one form of therapy to control pain and reduce disability. Based on current evidence, it is not possible to draw any firm conclusion regarding whether any form of analgesic or surgical technique can influence the generation of PTPS. Preemptive analgesia initiated prior to surgery shows promise and might help reduce the incidence of PTPS. Scientific evidence is steadily growing but there is still a need for large, prospective, randomized trials evaluating PTPS. Until more is known about this condition and how to prevent the central and peripheral nervous system changes that produce long-term pain after thoracotomy, patients must be warned preoperatively about the possibility of developing PTPS and how it might affect their quality of life after surgery. In addition, measures such as selecting the least traumatic and painful surgical approach, avoiding intercostal nerve trauma, and adopting an aggressive multimodal perioperative pain management regimen commenced before the surgical incision should be performed to prevent postthoracotomy pain syndrome.