International Research Foundation for RSD / CRPS

 

 

Scott S. Reuben, MD

Professor of Anesthesiology and Pain Medicine,

Department of Anesthesiology

Baystate Medical Center and the

Tufts University School of Medicine

Springfield, MA

Preventing phantom limb pain pain following surgery

 

Patients who suffer the loss of a limb, either traumatically or surgically, almost always report some degree of perceived sensation in the lost limb. A distinction should be made between phantom limb pain (painful sensations referred to the absent limb), phantom limb sensation (any sensation in the absent limb, except pain), and stump pain (pain localized in the stump), although each of these may coexist in an individual patient at different times [28]. Recent literature suggests that the incidence of phantom pain is probably between 50-80% [29-31]. Several risk factors have been identified for the development of phantom limb pain including the degree of preoperative pain, the magnitude of intraoperative noxious input, the intensity of postoperative pain, and psychological factors [32,33].

The mechanisms of phantom pain are not completely clear. As is the case with other types of neuropathic pain, there are likely both peripheral and central factors at play. Increased spontaneous activity of both afferent peripheral nerves and dorsal root ganglion cells has been observed experimentally following the transection of a nerve [5]. In addition, the sympathetic nervous system may have a role in sensitizing and maintaining the abnormal afferent output from damaged nerve fibers after amputation [5]. It is now known that the central nervous system,

including spinal cord, brainstem, thalamus and cerebral cortex, undergoes significant functional reorganization following amputation [34]. The degree to which this reorganization occurs has been correlated with the magnitude of phantom limb pain, underscoring the role that CNS plasticity has in the generation and maintenance of neuropathic pain [34].

Several investigations have focused on utilizing preventative regional analgesic techniques to reduce perioperative pain and long-term phantom pain following lower extremity amputation surgery [35]. Bach et al. [36] initially examined the effect of epidural morphine, epidural bupivacaine, or both in combination for three days before amputation (n=11) or conventional analgesia (n=14). All patients received epidural or spinal anesthesia for amputation and received conventional analgesics postoperatively. The incidence of phantom pain was reduced 6 months after amputation but not after 1 week or after 12 months in the epidural treatment group compared with the control group. Jahangiri et al. [37] confirmed the beneficial effects of perioperative epidural administration on preventing phantom pain following amputation surgery. These investigators examined the effect of an epidural infusion of bupivacaine, diamorphine and clonidine (n=13) preoperatively and maintained for at least 3 days postoperatively. For comparison, the control group (n=11) received on-demand opioid analgesia. These authors observed a significant reduction in the incidence of phantom pain at 1 year following surgery. However, the largest prospective study (n=60) to examine the effect of epidural analgesia on phantom pain failed to document any benefit at 7 days, 3 months, 6 months, and 12 months, postoperatively [38]. Similarly, clinical investigations evaluating the efficacy of continuous postoperative regional analgesia by nerve sheath block for amputation surgery have been equivocal with some studies revealing beneficial effects [39,40], while others have demonstrated no long-term benefit [41,42]. It is interesting that perineural analgesia provided for a reduction in phantom pain in these two studies [39,40] since this technique is ineffective in blocking nociceptive inputs from the pre- or intraoperative periods. A later study investigated whether postamputation stump and phantom pain could be reduced by preoperative epidural block with bupivacaine and diamorphine compared with intraoperative placement of a perineural catheter infusing bupivacaine [43]. These investigators observed that both regional techniques were equally effective in preventing phantom pain, but the epidural analgesic technique was more effective in relieving stump pain in the immediate postoperative period.

Unfortunately, many of the regional analgesic studies evaluating the effect on reducing long-term phantom pain have significant design flaws including: not prospective, randomized, or blinded, utilized either no control group or historical controls, investigated a heterogeneous study group, or lacked sufficient power. The authors of a recent systematic review of the literature concluded that because of the poor quality and contradictory results, the randomized and controlled trials do not provide evidence to support any particular treatment of phantom limb pain in the acute perioperative period or later [35].

 

PREVENTING OTHER CHRONIC PAIN DISORDERS

Chronic donor site pain (English)

Postthoracotomy pain syndrome (English)

Postmastectomy pain syndrome (English)

 

Part II: Algorithm for Perioperative Management of CRPS Patients

Part III: Highlights for Patients

 

References

 

 

 


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