Figure 11. Surgical decompression reduces pain response.

Mechanical allodynia was measured in mice in their fore and hind paws using a 0.4-g von Frey hair filament before DCM, during DCM, and after decompression. (A) The early-decompressed group was assessed before DCM (Bsl), 1 week before decompression (–1), as well as at 1, 2, and 5 weeks after decompressive surgery. We detected higher responses in the forepaws of animals in the DCM-E group compared with the Bsl time point. ***P < 0.001, two-tailed t test. Early surgical decompression reduced pain in the forepaws compared with the DCM-E group at all time points studied. ***P < 0.001, linear mixed model. (B) Pain response in the hind paws of the DCM-E group was not significantly affected at any time point. DCM-E before surgical decompression (n = 17); DCM-E (n = 8); DCM-E + Dec (n = 9). (C) Pain response was significantly increased in the forepaws of DCM-D animals compared with Bsl (***P < 0.001, two-tailed t test), without significant changes between the DCM-D and DCM-D + Dec groups. (D) In the hind paws, pain response was not significantly affected at any time point. DCM-D before surgical decompression (n = 20); DCM-D (n = 10); and DCM-D + Dec (n = 10). Each dot plot represents the mean of 10 measurements per paw, per animal. Results are presented as mean ± SEM. DCM, degenerative cervical myelopathy; Dec, decompression; DCM-E, age-matched early sham decompressed group; DCM-D, age-matched delayed sham decompressed group; w, weeks.