Artikel
Motorcortex stimulation fails in long-term pain control
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Veröffentlicht: | 13. Mai 2014 |
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Gliederung
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Objective: Motorcortex stimulation (MCS) is being advocated for different neuropathic pain disorders including atypical facial pain, trigeminal neuralgia, thalamic post stroke pain and plexus avulsion. Common indications are treatment attempts in patients resistant to other treatment options. Therefore data on MCS success and especially long-term follow-up is limited to small case series and case reports and follow-up usually short. We report a long-term retrospective analysis of 23 patients being treated by MCS for various disorders.
Method: Data of 23 patients being treated by MCS for different disorders was retrospectively analyzed. All patients were treated in two large neuromodulation centers in Germany and Austria. Reduction in pain on the visual analogue scale (VAS) was the primary outcome parameter, explantation of the system secondary outcome. Patients were divided in outcome groups (responder/non-responder) depending on pain reduction in last follow-up (>30% compared to best medical treatment). VAS pain level and special events were documented at 1/3/6/12/18/24 month follow-up. VAS results were compared to best medical treatment prior to implantation.
Results: 9 patients were classified as responders, 14 as non-responders. Most patients did experience a reduction in pain during the first 6 months of treatment. A decline in treatment effect is commonly seen in ongoing follow-ups. Whereas significant pain reduction is seen until next-to-last follow-up (18 month) no significant pain reduction compared to best medical treatment is observed in the last follow-up. Overall 6 patients had their device explanted during follow-up due to missing treatment effect.
Conclusions: MCS offers a treatment attempt in patients resistant to common pain therapies including neuromodulation techniques as SCS. Whereas short-term results are promising in this retrospective study MCS fails in long-term pain control. Treatment effect in MCS is moderated by modulation of thalamic pain processing via cortico-thalamic tracts. Recent publications indicate that neural plasticity voids long-term treatment effects.