Brain reorganization in patients with spinal cord compression evaluated using fMRI.

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.