Amputation and phantom limb pain: a pain-prevention model.

Within the figure of more than 200,000 surgical amputations performed in the United States each year lies another--70% of patients experience phantom limb pain after the procedure, and 50% still experience phantom pain 5 years after surgery. Patients describe burning, stabbing, twisting, cramping, or throbbing pains in the missing part. Adding to the patient's and the anesthesia professional's conundrum has been the lack of a simple model that tissue injury produces pain. The patient with a surgical amputation who experiences phantom limb pain can have several sources for discomfort including problems from the original tissue injury or from pathology, e.g., scarring or continued cellular dysfunction resulting from diabetes, ischemia, or infection. Suboptimal prosthesis fit and tissues and joints connected to the affected part can continue to generate pain long after surgical wound healing. In addition, nonaffected tissues and joints now made to carry extra loads as a result of altered gait and balance can sustain collateral stress and damage and produce nociception. In addition to this series of problems, amputee patients remain susceptible to the pain problems experienced by the general population. There is a positive correlation between a painful limb before amputation and experiencing chronic phantom limb pain. Authors have described patients with preamputation pain who benefited from effective preemptive analgesia and experienced less phantom limb pain. CRNAs can have a significant role in providing anesthesia and analgesia services to these patients and can begin to think in terms of preventing lifelong pain.