Percutaneous leads located over a human dorsal dural sac at the cervical level. (a, b) Positioning of percutaneous lead on the dural sac. (c) Transversal section of spinal cord with the lead on the posterior surface of the dural sac. (d) The dural sac was removed, showing the posterior surface of the spinal cord. The area where the lead lies in direct contact with the spinal cord and rootlets is the area where the electrical field is generated and spread across the dural sac

Percutaneous leads and paddle leads located over a human dorsal dural sac at the cervical level. (a, d) Different designs of percutaneous leads. (b, c) Different designs of paddle leads. The size of the dural sac and the size occupied by the leads can be identified

Percutaneous leads and paddle leads located over a human dorsal dural sac at the cervical level. (a) Paddle leads of two columns. (b, c) Percutaneous leads above the dural sac and internal structures affected by the electrical field below the dural sac

Paddle leads located over a human dorsal dural sac at the cervical level. The size of the dural sac and the size occupied by the leads can be identified. (a, b) Same paddle lead, (a) The paddle lead is inverted to show the electrodes (b) The paddle lead is positioned correctly. (c, d) Same paddle lead with another design, (c) The paddle lead is inverted to show the electrodes (d) The paddle lead is positioned correctly. (From De Andrés et al. [3]; with permission)

Dorsal root ganglion stimulation at the cervical level. (a) The contacts of the percutaneous lead are close to the dorsal root ganglion. (b) Three-dimensional (3D) reconstruction from MRI of a patient. (c) Radiograph during placement of a percutaneous lead for dorsal root ganglion stimulation

Dorsal root ganglion stimulation at cervical and thoracic levels. The contacts of the percutaneous lead are close to the dorsal root ganglion. (a, b) Cervical level; (c, d) Thoracic level