This prospective observational study will evaluate pain outcomes in patients with neuropathic dental pain (Atypical Odontalgia/Phantom Tooth Pain) who undergo directional deep brain stimulation (DBS). Participants will complete validated pain, disability, quality-of-life, and mood assessments before surgery and following DBS programming. Directional stimulation will be applied to different thalamic targets to determine whether specific stimulation settings are associated with greater pain relief. The study aims to characterize changes in pain and quality of life following DBS and to identify the stimulation target associated with the greatest reduction in neuropathic dental pain.
Neuropathic dental pain, also known as Atypical Odontalgia (AO) or Phantom Tooth Pain (PTP), is a chronic pain condition characterized by persistent tooth or facial pain in the absence of identifiable dental pathology. The condition is thought to result from injury to peripheral nerve structures that leads to alterations in central pain processing. Standard treatments, including antidepressants, neuroleptic medications, local anesthetic injections, corticosteroids, and nerve blocks, may provide relief for some patients; however, a subset of patients continue to experience debilitating pain despite these interventions. Deep brain stimulation (DBS) is an established neurosurgical therapy for several neurological disorders and has been used off-label for the treatment of chronic neuropathic pain. Previous studies suggest that stimulation of thalamic structures involved in pain processing, including the ventral posteromedial nucleus (VPM), centromedian nucleus (CM), and anterior pulvinar (aPu), may provide pain relief for neuropathic facial pain. However, no established DBS target currently exists for neuropathic dental pain. This prospective observational study will evaluate pain outcomes in patients with neuropathic dental pain who undergo directional DBS. Directional DBS leads will be implanted in a location that permits stimulation of the VPM, CM, and aPu regions of the thalamus. Following surgery, participants will undergo routine clinical programming during which stimulation settings will be systematically adjusted to direct stimulation toward each target region, as well as ring-mode stimulation and an off-stimulation condition. Participants will remain blinded to the stimulation settings. Participants will complete validated measures of pain, pain-related disability, quality of life, and depressive symptoms before surgery and after completion of the programming period. Visual Analog Scale (VAS) pain ratings will also be collected following each stimulation condition to evaluate differences in pain relief between targets. The primary objective is to assess changes in pain levels associated with different stimulation settings and identify the stimulation target associated with the greatest reduction in neuropathic dental pain. Secondary objectives include evaluating changes in pain-related disability, quality of life, and mood following DBS treatment. The findings from this study will provide preliminary evidence regarding optimal thalamic stimulation targets for neuropathic dental pain and may inform future research and treatment approaches for patients with this challenging and currently underserved condition.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
5
Participants will receive standard-of-care directional deep brain stimulation (DBS) using an implanted DBS system. Stimulation will be delivered using ring-mode stimulation, directional stimulation toward the ventral posteromedial nucleus (VPM), anterior pulvinar (aPu), or centromedian nucleus (CM), or with stimulation turned off. Participants will undergo each stimulation condition in a randomized sequence.
Vancouver General Hospital
Vancouver, British Columbia, Canada
RECRUITINGPain Severity Measured by Visual Analogue Scale (VAS)
Pain severity will be assessed using the Visual Analogue Scale (VAS). Participants will complete the VAS following two weeks on each of five stimulation settings (ring mode, VPM, aPu, CM, and off stimulation). The primary outcome is the comparison of VAS scores across stimulation settings to identify the setting associated with the greatest pain reduction.
Time frame: Baseline (pre-operative); after each 2-week stimulation period during the 10-week post-activation programming phase; and 3 months after completion of the randomized stimulation period.
Change in Pain Severity Assessed by the Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2)
Pain characteristics and severity will be assessed using the SF-MPQ-2. Changes from baseline to follow-up will be evaluated.
Time frame: Baseline (pre-operative) and 3 months after completion of the randomized stimulation period.
Change in Pain-Related Disability Assessed by the Pain Disability Index (PDI)
The impact of pain on daily functioning will be measured using the Pain Disability Index. Changes from baseline to follow-up will be evaluated.
Time frame: Baseline (pre-operative) and 3 months after completion of the randomized stimulation period.
Change in Health-Related Quality of Life Assessed by the 36-Item Short Form Survey (SF-36)
Health-related quality of life will be measured using the SF-36 questionnaire. Changes from baseline to follow-up will be evaluated.
Time frame: Baseline (pre-operative) and 3 months after completion of the randomized stimulation period.
Change in Depressive Symptoms Assessed by the Beck Depression Inventory (BDI)
Depressive symptoms will be measured using the Beck Depression Inventory. Changes from baseline to follow-up will be evaluated.
Time frame: Baseline (pre-operative) and 3 months after completion of the randomized stimulation period.
Change in Pain Severity Assessed by the Visual Analogue Scale (VAS)
Overall pain intensity will be compared between baseline and follow-up while participants are maintained on their optimal stimulation setting.
Time frame: Baseline (pre-operative) and 3 months after completion of the randomized stimulation period.
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