Phantom Limb Pain

Original Editor - Peter Le Feuvre

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POST AMPUTATION PAIN AND PHANTOM LIMB PAIN: KEY MESSAGES

Pain is an inevitable consequence of amputation, and for many, pain will not just result from the trauma of the surgery, but will also include a neuropathic presentation known as phantom limb pain (PLP). When amputation has resulted from a traumatic incident, such as in a disaster setting, this can be complicated by co-existing injury to the same limb or other parts of the body. For the physiotherapists involved in the early and post acute stages of rehabilitation, the challenge is determining the nociceptive and neuropathic causes which require attention in order to manage the patient and so enable effective rehabilitation to occur.

Table 1 contains an assessment approach which may help clinicians to determine the correct course of action required with a patient. The assessment must commence by accurately identifying that PLP is indeed the issue. A knowledge of the different characteristics of each pain presentation (below) will help the clinician to establish this from an assessment of their history:

1. Post-Amputation Pain: Post-amputation pain at the wound site should also be distinguished from pain in the residual limb and the phantom limb. After amputation, all three may occur together
2. Residual Limb Pain: PLP is often confused with pain or sensation in the areas adjacent to the amputated body part. This is known as residual limb (RLP) or stump pain and its intensity is often positively correlated with PLP.
3. Phantom Limb Sensation: This is a normal experience for the majority of amputees, but it is not a noxious sensation, which might be described by the patient as unpleasant. Often it can be described as a light tingling sensation, or In such cases re-assurance is the key.
4. Phantom Limb Pain: Classified as neuropathic pain, whereas RLP and post-amputation pain are classified as nociceptive pain. PLP is often more intense in the distal portion of the phantom limb and can be exacerbated or elicited by physical factors (pressure on the residual limb, time of day, weather) and psychological factors, such as emotional stress. Commonly used descriptors include sharp, cramping, burning, electric, jumping, crushing and cramping.

The assessment should then seek to establish the principle driver(s) of the PLP. These may be centrally driven adaptation, peripheral sensitisation, mental state or social concerns, and musculoskeletal factors. Treatment should target these drivers. See table 2 for more detail and suggested treatments.

Objective Measurement: In addition to completing a pain chart, measurement of pain intensity is helpful. The brief pain inventory (BPI) is one method of charting the intensity of symptoms, however it takes time to administer. The 0-3 VAS is an easy to administer scale which highlights when intervention is required. It is also easy to fit it with the WHO pain ladder (Figure 1). In short, scores of 0 and 1 (nil to mild pain) require no intervention, 2 and 3 (moderate to severe) requires immediate action.