We hypothesised that unilateral leg pain following surgical treatment of lumbar disc herniation (LDH) is associated with an increase in the glucose metabolism of the contralateral thalamus. Patients scheduled for surgery due to LDH underwent 18 F-uorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) less than two weeks prior to surgery. Their thalamic FDG uptake was measured and expressed as the mean and partial volume corrected mean standardized uptake values (SUVmean and cSUVmean). These measures were compared with patient-related outcome measures collected pre-and 1-year postoperatively: back and leg pain on a 0-100 VAS scale and health related quality of life as measured by the EuroQol-5D (EQ-5D). Twenty-six patients (10 females) aged 49.7 ± 7.4 (mean ± SD) years were included. There was a signi cant correlation between painful body side and increased contralateral thalamic uptake of FDG, with regard to cSUVmean values. Correlation analyses including clinical parameters and cSUVmean indicated some association with 1-year change in EQ-5D.These preliminary data sustain the hypothesis that unilateral pain in patients with LDH is associated with increased glucose metabolism in the contralateral thalamus, suggestion a central role of thalamus in chronic pain perception.