Importance of axial migration of spinal cord stimulation trial leads with position.

BACKGROUND Spinal cord stimulation (SCS) is an established treatment option for chronic pain. Prior to permanent implantation, temporary trials are performed to evaluate the SCS treatment. During the trial period, it is common for the patients to experience changes in paresthesias. However, it is unclear what the role of lead migration is, if any, in the changes in paresthesia. OBJECTIVE To evaluate the role of lead migration on the effect of postural stimulation changes during SCS trials. STUDY DESIGN Case series. SETTING University pain management center. METHODS X-rays of the patients with successful trials, in sitting and standing position, were obtained at the end of a 7 day SCS trial. Data were collected based on the need for adjustment of the stimulation settings due to changes in paresthesias with postural change of sitting versus standing. RESULTS The average lead migration was 3.05 mm inferiorly from a standing to sitting position for all subjects. The average migration was 2.85 mm in subjects requiring adjustment of the SCS setting due to change in paresthesia compared to 3.24 mm for those who did not require adjustment regardless of position. The results were insignificant based on P = 0.17. LIMITATIONS Small sample size, case series. CONCLUSIONS This case series demonstrates continued support for the role of the width of the cerebral spinal fluid space as the significant factor on paresthesia changes in SCS with respect to postural changes, even during the trial period.