Immediate alleviation of chronic pain by bone drilling and probable involvement of bone tissue in pain sensitisation.

Three patients presented with severe spontaneous pain, allodynia and numbness on the lateral side of the left heal, foot and/or toe due to L5 and/or S1 root injury, as a result of repeated failed back surgeries including Love's surgery and laminaectomy (failed back surgery syndrome). The neuropathic pain in the lower extremities did not respond to somatic nerve block, lumbar-sympathetic ganglion block, spinal cord stimulation, and/or medications. At the spots in the foot showing the most severe allodynia, bones were drilled with fluoroscopic assistance. Spontaneous pain diminished immediately and allodynia was completely resolved. Visual analogue scale score decreased immediately after bone drilling. The analgesic effect was maintained for 30-45 weeks. In three patients, drilling until the marrow cavity of the bones at painful sites effectively relieved chronic neuropathic pain with lasting analgesic effect.