Compression of Thoracic Spinal Cord with Decreased Cerebrospinal Fluid Space After Implantation of Paddle Lead Spinal Cord Stimulation at T9: A Three-Dimensional Myelographic Computed Tomography Study.

OBJECTIVES: To investigate the extent of spinal cord compression and cerebrospinal fluid (CSF) space after T9 paddle lead spinal cord stimulation (SCS) using three-dimensional myelographic computed tomography scans.

METHODS: Preoperative and postoperative three-dimensional myelographic computed tomography scans were performed in 15 patients with paddle lead SCS at T9 for neuropathic back and leg pain. Four axial levels between each row of the electrodes were selected and the cross-sectional areas of thecal sac and spinal cord, the width of anterior and posterior CSF space, and contact angle of the lead within T9 spinal canal were measured with 12-month pain relief assessment.

RESULTS: The cross-sectional areas of thecal sac and spinal cord under each contact of paddle leads decreased significantly (23.89 ± 11.48% and 9.45 ± 4.80%; P < 0.05, respectively). The width of posterior CSF space decreased by 38.65 ± 20.97% and that of anterior CSF space showed a greater reduction by 59.09 ± 18.39% (P < 0.05). We achieved a mean pain relief of 45.49 ± 13.73% at 12-month follow-up and found a significant correlation with percentage reduction in the area of the spinal cord.

CONCLUSIONS: Significant reduction in the cross-sectional area of spinal cord and anterior CSF space as well as thecal sac and posterior CSF space resulted in deformation of the spinal cord under paddle leads at T9 within 7 postoperative days. Close approximation to the dorsal column and the mass effect of paddle leads may determine the clinical outcome of paddle lead SCS and also raise safety concerns.