Introduction: Burst stimulation is a new paradigm that eliminates paresthesias typically observed with traditional tonic stimulation. We used a rodent model of episodic migraine to compare the efficacy of tonic and burst stimulation in treating trigeminal allodynia.
Methods: Twelve Sprague-Dawley rats with spontaneous trigeminal allodynia1 were implanted with miniaturized paddle leads over the occipital nerves, and the leads connected to a pulse generator located dorsally. Rats were randomized to receive four frequencies: tonic 60Hz, tonic 500Hz, burst 40Hz, and burst 50Hz. Tonic 500Hz and burst 50Hz were the most effective parameters on short-term trials carried out previously. Tonic 60Hz and burst 40Hz are the most common parameters in clinical use. After establishing baseline hypersensitivity, the stimulation was turned ON for 10 days, followed by OFF for 10 days. Daily periorbital sensitivity was assessed using von Frey filaments(VFF). Rats were characterized as hypersensitive or as responders when VFF thresholds were =4g or =6g, respectively. ANOVA tests were used for analysis.
Results: Overall, both tonic and burst ONS significantly improved VFF thresholds compared to baseline (p<0.005). Tonic stimulations had a superior response (p=0.022) on day 1, but the burst stimulations produced superior efficacy from day 3. On 3,4,6, and 9 of ON days, there were statistically superior reduction of allodynia observed for burst stimulations. After the STIM was turned OFF on day 10, tonic stimulations lost efficacy sooner while burst stimulations had trend in maintaining superior efficacy for additional day (day 11,p=0.053).
Conclusions: Tonic stimulation had superior take off efficacy, but there was a latent positive response associated with burst stimulation that made it superior to tonic stimulation. Additionally, burst stimulations exhibited a better therapeutic carryover effect that lasted for a day after stimulation was OFF. Human trials of burst stimulation for headache disorders are warranted to clinically validate our results.
Patient Care: This translational research result may stipulate the human trial of occipital nerve stimulation for chronic headache using burst stimulation parameters. This can potentially lead to increased patient response rate to this therapy.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the difference between the new burst stimulation paradigm from conventional tonic stimulation..., 2) Discuss, in small groups the significance of carrying out preclinical trials using animal model of migraine becuase it solves the blinding issues related to paresthesias 3) Identify benefit of using burst stimulation being overall superior efficacy for abolishing hypersensitivity as well as the superior preventative effect after burst stimulation is turned OFF.