Tractography Study of Deep Brain Stimulation of the Anterior Cingulate Cortex in Chronic Pain: Key to Improve the Targeting.
BACKGROUND
Deep brain stimulation (DBS) of the anterior cingulate cortex (ACC) is a new treatment for alleviating intractable neuropathic pain. However, it fails to help some patients. The large size of the ACC and the intersubject variability make it difficult to determine the optimal site to position DBS electrodes. The aim of this work was therefore to compare the ACC connectivity of patients with successful versus unsuccessful DBS outcomes to help guide future electrode placement.


METHODS
Diffusion magnetic resonance imaging (dMRI) and probabilistic tractography were performed preoperatively in 8 chronic pain patients (age 53.4 ± 6.1 years, 2 females) with ACC DBS, of whom 6 had successful (SO) and 2 unsuccessful outcomes (UOs) during a period of trialing.


RESULTS
The number of patients was too small to demonstrate any statistically significant differences. Nevertheless, we observed differences between patients with successful and unsuccessful outcomes in the fiber tract projections emanating from the volume of activated tissue around the electrodes. A strong connectivity to the precuneus area seems to predict unsuccessful outcomes in our patients (UO: 160n/SO: 27n), with (n), the number of streamlines per nonzero voxel. On the other hand, connectivity to the thalamus and brainstem through the medial forebrain bundle (MFB) was only observed in SO patients.


CONCLUSIONS
These findings could help improve presurgical planning by optimizing electrode placement, to selectively target the tracts that help to relieve patients' pain and to avoid those leading to unwanted effects.
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom. Electronic address: sandra.boccard@ndcn.ox.ac.uk.
Sandra G J
SG
Boccard
Department of Psychiatry, University of Oxford, United Kingdom; CFIN/MindLab, Aarhus University, Aarhus, Denmark.
Henrique M
HM
Fernandes
Centre for Functional MRI of the Brain (FMRIB), University of Oxford, United Kingdom.
Saad
S
Jbabdi
Department of Psychiatry, University of Oxford, United Kingdom; CFIN/MindLab, Aarhus University, Aarhus, Denmark.
Tim J
TJ
Van Hartevelt
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom; Department of Psychiatry, University of Oxford, United Kingdom; CFIN/MindLab, Aarhus University, Aarhus, Denmark.
Morten L
ML
Kringelbach
Department of Neuroradiology, John Radcliffe Hospital, Oxford, United Kingdom.
Gerardine
G
Quaghebeur
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom.
Liz
L
Moir
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom.
Victor Piqueras
VP
Mancebo
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom.
Erlick A C
EA
Pereira
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom.
James J
JJ
Fitzgerald
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom.
Alexander L
AL
Green
Department of Physiology, Anatomy, & Genetics, University of Oxford, United Kingdom.
John
J
Stein
Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, United Kingdom.
Tipu Z
TZ
Aziz
D059350:Chronic Pain / Q000601:surgery*; D046690:Deep Brain Stimulation / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004566:Electrodes; D005260:Female; D006179:Gyrus Cinguli / Q000033:anatomy & histology* / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008474:Medial Forebrain Bundle / Q000033:anatomy & histology / Q000601:surgery; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D010147:Pain Measurement; D013788:Thalamus / Q000033:anatomy & histology / Q000601:surgery; D016896:Treatment Outcome
Anterior cingulate cortex; Deep brain stimulation; Precuneus; Targeting; Tractography