OBJECTIVE - This prospective study characterizes the reorganization that occurs within the primary sensorimotor cortices following decompression of cervical spinal stenosis.
METHODS - Twelve right-handed patients with cervical myelopathy underwent blood oxygenation level dependent functional MRI (fMRI) prior to decompression and 6 months following surgery. Ten right-handed controls also underwent fMRI. All subjects performed a finger-tapping paradigm with the right hand. Volume time course data were corrected for temporal serial correlation and % normalized before inclusion in the general linear model. Activation maps were created for each group using a threshold of p < 0.005 with Bonferroni correction. Between-group differences in left hemisphere volume of activation (VOA) were measured along the precentral gyrus (PrCG) and postcentral gyrus (PoCG). Each subject also completed clinical questionnaires.
RESULTS - Prior to surgery, patients demonstrated a larger VOA (1.23 cm(3), t(max) = 11.8) in comparison to controls within the PrCG. This difference increased following surgery (2.99 cm(3), t(max) = 13.6). Within the PoCG, controls demonstrated a larger VOA (0.53 cm(3), t(max) = 8.28) than preoperative patients. This difference decreased by 0.12 cm(3) (t(max) = 7.05) following surgery. Preoperatively, patients had a 21.7 cm(3) VOA (t(max) = 29.4) within the sensorimotor cortex with the center of gravity located within Brodmann area (BA) 3. Following surgery, the VOA increased to 23.1 cm(3) (t(max) = 26.1) within BA 3. There were significant improvements in clinical outcomes following surgery.
CONCLUSIONS - Spinal cord compression resulted in an increase in volume of activation (VOA) within the precentral gyrus (PrCG) and a loss of VOA within the postcentral gyrus (PoCG) in comparison to controls. Surgical decompression results in cortical reorganization with enlarging VOA within both the PrCG and PoCG.