Electron microscopic observations of degeneration of human Pacinian corpuscles in amputated fingers.

Amputated human fingers were used to observe the morphologic changes in degeneration of Pacinian corpuscles, and postoperative moving two-point discrimination of the replanted fingers was examined to analyze sensory recovery after replantation. Normal corpuscles are composed of an axon terminal and inner and outer cores, resembling a sliced onion. The inner core is composed of thin, multilayered lamellar cells, and the outer core consists of multiple layers of thin perineurial cells. Based on our morphologic findings, following mitochondrial degeneration in the axon terminal, the terminal and inner core cells disappeared within 9 to 16 hours, but the outer core did not lose its structure until more than 24 hours after amputation. Collagen fibrils in the corpuscles appeared from 5 hours after amputation and periodically increased their amount up to 27 hours after amputation. Postoperative sensory recovery of the replanted fingers was significantly poorer with 9 hours or more of cold ischemia. These findings suggest that the inner core cells originating from Schwann cells degenerate at over 9 hours after amputation, and this may be related to the poor sensory recovery of replanted fingers. It also appears that the outer core cells originating from the perineurial cells in the amputated fingers survive even up to 27 hours after amputation and produce collagen fibrils in the extramatrix spaces of the outer core cells.