Analysis of VPL/VPM DBS combined PAG/PVG DBS for treatment of neuropathic pain

Abstract

Objective To discuss the treatment of neuropathic pain with ventral posteromedial thalamic nucleus/ventral posterolateral thalamic nucleus (VPL/VPM) DBS combined periventricular/ periaqueductal grey matter (PAG/PVG) DBS. Methods A retrospective analysis of 24 patients with neuropathic pain was performed. At the early time,two patients just accepted PVG - DBS.The other patients were treated by VPL/VPM DBS combined PAG/PVG DBS.The effects of stimulation were studied right after electrode insertion or the stimulation trials was done after 5 - 7days after surgery.Patients with a greater than 50％ reduction in pain visual analogue score (VAS) were implanted with a pulse generator (IPG).VAS was also recorded before operation and three months after the operation.Results All the patients tolerated the procedure very well.17 of them received good outcome.The instrument had to be removed in the other 7 patients because of infection ( n =1 ) or invalid efficacy ( n =6 ).The average VAS score before surgery was 8.04 ±0.86 and the average VAS score after surgery was 3.13 ± 1.44.There was significant difference.All effective patients had good outcomes when the VPL - DBS was on and 12 patients received good outcomes when the PVG - DBS was on.7 patients with PVG - DBS had severe side effects.There was no significant side effect in patients with VPL - DBS. Conclusions Many doctors prefer to combine VPL and PVG DBS to treat chronic neuropathic pain.But the efficacy and side effects of PVG target are not so satisfied.VPL DBS used alone may be accepted by more and more doctors. Key words: Neuropathic pain; Deep brain stimulator (DBS) ; Treatment outcome