Preoperative state anxiety, acute postoperative pain, and analgesic use in persons undergoing lower limb amputation

The current study examined the relationship between preoperative anxiety and acute postoperative phantom limb pain (PLP), residual limb pain (RLP), and analgesic medication use in a sample of persons undergoing lower limb amputation.

Participants included 69 adults admitted to a large level 1 trauma hospital for lower limb amputation. Participants' average pain and anxiety during the previous week were assessed before amputation surgery. RLP, PLP, and analgesic medication use were measured on each of the 5 days following amputation surgery.

Results of partial-order correlations indicated that greater preoperative anxiety was significantly associated with greater ratings of average PLP for each of the 5 days following amputation surgery, after controlling for preoperative pain ratings and daily postoperative analgesic medication use. Partial correlation values ranged from 0.30 to 0.62, indicating medium to large effects. Preoperative anxiety was also significantly associated with ratings of average RLP only on postoperative day 1, after controlling for preoperative pain ratings and daily postoperative analgesic medication use (r=0.34, P<0.05). Correlations between preoperative anxiety and daily postoperative analgesic medication dose became nonsignificant when controlling for preamputation and postamputation pain ratings.

These findings suggest that anxiety may be a risk factor for acute postamputation PLP and RLP, and indicate that further research to examine these associations is warranted. If replicated, the findings would support research to examine the extent to which modifying preoperative anxiety yields a reduction in postoperative acute PLP and RLP.