Cutaneous innervation in man before and after lumbar sympathectomy: Evidence for interruption of both sensory and vasomotor nerve fibres

Background: Rest pain and severe ischaemia in patients who are unable to be offered (further) surgery to revascularize the lower limb is still problematic. Lumbar sympathectomy has been used for many years but the mechanisms by which this works are not absolutely clear. Both sensory and vasomotor fibres travel in the lumbar sympathetic chain and the effects of lumbar sympathectomy on these nerve types have been investigated in the present paper. Methods: Immunohistochemical methods were used to detect neuropeptides contained in sensory and vasomotor nerves in the lower limb skin of (i) patients having amputations for peripheral vascular disease (PVD) after previous (chemical or surgical) sympathectomy; (ii) patients having amputations for PVD without previous (chemical or surgical) sympathectomy; and in control normal skin. The three groups are compared and the results are discussed. Results: Normal and PVD controls had intact sensory and vasomotor nerves around dermal cutaneous blood vessels, but these were completely or virtually completely lost after lumbar sympathectomy, by either chemical or surgical means. Conclusions: Lumbar sympathectomy severs both vasomotor and sensory fibres, suggesting that relief of rest pain may be explained not only by increased cutaneous and muscle blood flow, but also by nociceptive sensory denervation.