Rates of lead migration and stimulation loss in spinal cord stimulation: a retrospective comparison of laminotomy versus percutaneous implantation.

BACKGROUND Neuromodulation has been used to treat neuropathic pain. Leads have been implanted using laminotomy or percutaneous approaches. Laminotomy implantation has been shown to be superior in terms of lead migration when compared to percutaneous implantation. Lead migration has been reported as high as 68% with the percutaneous approach. Because of this, newer anchors have been developed but not tested in vivo. OBJECTIVES This study tests the hypothesis that newer anchoring systems have improved lead migration rates for percutaneous leads relative to laminotomy leads to the point of parity. This study also analyzed if factors such as laterality of symptoms, lead type, level of implant and diagnosis affect migration rates. STUDY DESIGN Neurostimulators implanted in the thoracolumbar spine at Henry Ford Hospital between 2006 and 2008 were reviewed for the following: age, sex, diagnosis, lead type, and implant level. Implants were reviewed for the following: age, sex, diagnosis, lead type, implant level, implant method, symptom laterality, loss of stimulation, radiographic lead migration, and time to loss. Loss of capture and lead migration in the laminotomy and percutaneous groups were compared using Fisher's exact test. Variables within each group included: lead type, level of implantation, location of symptoms, and diagnosis. They were compared using Fisher's exact test. Time to loss of stimulation was compared using the Wilcoxon 2-sample test. SETTING Pain Clinic, Henry Ford Hospital, Detroit, MI. RESULTS Laminotomies were performed by a single neurosurgeon and percutaneous implants were performed by a single pain medicine specialist. Percutaneous leads were anchored using Titan (Medtronic Corporation, Minneapolis, MN) anchors. Loss of capture was 24% laminotomy and 23% percutaneous with no significant difference between the 2 groups (P = 0.787). Radiographic evidence of migration was 13.63% percutaneous and 12.67% laminotomy with no significant difference (P = 0.999). The average days to loss of stimulation for the laminotomy versus percutaneous were as follows: 124.82 and 323.6 which were not statistically significant. There was no statistical difference in the days to loss of capture between the groups (P = 0.060). There was no significant difference between unilateral or bilateral symptoms in loss of capture within either group (P = 0.263, P = 0.326). There was not enough data to do comparisons by diagnosis. Comparisons of loss of capture based on electrode type was not significant in either group (P = 0.687, P = 0.371). The effect of the spinal level on the lack of recapture rates was not able to be calculated due to the number of levels. LIMITATIONS Retrospective study. CONCLUSION Rates of stimulation loss and radiographic lead migration are similar for both laminotomy and percutaneous implantation. Time to loss of stimulation was not statistically different in either group, although there was a trend toward laminotomy leads migrating earlier. Lead type and laterality of symptoms do not affect lead migration rates. The effect of the level of implant and diagnosis was indeterminate.