The CHAMPION trial (NCT05550714) is a prospective, randomized, open-label, non-inferiority study comparing general anesthesia with desflurane versus conscious sedation with dexmedetomidine during microelectrode recording (MER)-guided bilateral STN-deep brain stimulation (DBS) for [Parkinson's disease](/diseases/parkinsons-disease). The study addresses a critical clinical question: can patients who cannot tolerate awake surgery safely receive MER-guided DBS under general anesthesia without compromising signal quality and clinical outcomes?
STN-DBS under general anesthesia has become increasingly common for patients who cannot tolerate awake surgery, but volatile anesthetics like desflurane may suppress neuronal firing rates and alter MER signal characteristics, potentially reducing targeting accuracy. The CHAMPION trial aims to determine whether conscious sedation is non-inferior to general anesthesia for MER signal quality, while also comparing secondary surgical and clinical outcomes.
| Parameter | Value |
|-----------|-------|
| NCT Number | NCT05550714 |
| Title | Choice of Anesthesia in Microelectrode Recording Guided Deep Brain Stimulation for Parkinson's Disease (CHAMPION) |
| Status | Recruiting |
| Phase | Not Applicable (Non-inferiority RCT) |
| Sponsor | [Beijing Tiantan Hospital](/institutions/capital-medical-university), Capital Medical University |
| Principal Investigator | Ruquan Han, MD, PhD — Director of Anesthesiology Department |
| Study Type | Interventional |
| Allocation | Randomized (1:1) |
| Masking | Single-blind (outcomes assessor) |
| Enrollment | 188 participants (estimated) |
| Start Date | October 15, 2022 (actual) |
| Primary Completion | March 26, 2024 (actual) |
| Estimated Completion | September 30, 2024 |
| Location | Beijing, China |
| Registration | [ClinicalTrials.gov NCT05550714](https://clinicaltrials.gov/study/NCT05550714) |
Microelectrode recording during STN-DBS surgery provides real-time electrophysiological confirmation of electrode placement. MER signals from STN neurons exhibit:
Volatile anesthetics (desflurane, sevoflurane, isoflurane) exert dose-dependent effects on subthalamic nucleus neurons:
Dexmedetomidine, an alpha-2 adrenergic agonist, produces sedation via endogenous sleep pathways and has been shown to preserve neuronal firing rates better than volatile anesthetics in some studies. However, dexmedetomidine can also suppress neuronal activity at higher doses.
The conscious sedation arm uses an "asleep-awake-asleep" (SAS) technique:
The GA protocol follows:
The CS protocol uses dexmedetomidine:
Proportion of high-normalized root mean square (high-NRMS) MER signals
The normalized RMS (NRMS) is computed by dividing each session's RMS by the mean RMS of the first five stable pre-STN sessions in the same trajectory. An NRMS > 2.0 (entry signal is twice the pre-STN baseline) is defined as "high" — indicating confident STN identification.
Non-inferiority margin is defined as: if the GA group achieves ≥ 90% of the CS group's high-NRMS proportion, GA is considered non-inferior.
| Outcome | Description | Timeframe |
|---------|-------------|-----------|
| NRMS values | Mean and stratified NRMS proportions | During MER |
| Firing rates | STN neuronal firing rates | During MER |
| STN length | Distance from STN entry to exit (mm) | During MER |
| MER track count | Total electrode paths selected | During MER |
| Beta oscillations | 13-30 Hz power spectral density | During MER |
| Remedial measures | Incidence of rescue interventions | During MER |
| DBS accuracy | Postoperative CT confirmation of target | Within 24 hours |
| Outcome | Description | Timeframe |
|---------|-------------|-----------|
| UPDRS-III | Unified Parkinson's Disease Rating Scale Part III | 6 months post-op |
| LEDD reduction | Levodopa equivalent daily dose | 6 months post-op |
| Cognitive function | MMSE and MoCA scores | Baseline, 24h, 2d, 3d, 6m |
| Quality of life | PDQ-39 scores | 6 months post-op |
| Surgical complications | Second operation, infection, hemorrhage | Up to 6 months |
| Anesthesia complications | Nausea, vomiting, intraoperative awareness | Up to 3 days |
| Patient satisfaction | 7-point Likert scale | 24h post-op, 6 months |
The subthalamic nucleus is a small (approximately 8mm in diameter) ovoid structure located posteromedial to the substantia nigra. Precise electrode placement within the STN — particularly in the dorsolateral "sensorimotor" region — is critical for optimal motor outcomes and minimal side effects.
MER provides real-time physiological feedback:
MER Signal Characteristics During STN Trajectory:
Zone Incerta (pre-STN) → STN Entry → STN Body → STN Exit → Substantia Nigra
Baseline: 5-15 spikes/s → ↑↑↑ 30-60 spikes/s → ↓ gradual → ↓↓ <10 spikes/s
NRMS: ~0.5-0.8 → 2.0-5.0+ → ↓ → ~0.3-0.5
Beta: Low → High (pathological) → Moderate → Low
Anesthetics that suppress this signal contrast make it harder to precisely identify the STN borders, potentially leading to suboptimal electrode placement.
If dexmedetomidine-based conscious sedation proves non-inferior to general anesthesia for MER quality, this would:
Even if general anesthesia proves non-inferior (i.e., desflurane does not significantly compromise MER signals), the trial will provide the first rigorous comparison of these two approaches with standardized outcome measures.