Efficacy of hypothalamic stimulation for chronic drug-resistant cluster headache

Neurosurgical Treatment of Pain

The aim of this review is to draw attention to neurosurgical approaches for treating chronic and opioid-resistant pain. In a first chapter, an up-to-date overview of the main pathophysiological mechanisms of pain has been carried out, with special emphasis on the details in which the surgical treatment is based. In a second part, the principal indications and results of different surgical approaches are reviewed. Cordotomy, Myelotomy, DREZ lesions, Trigeminal Nucleotomy, Mesencephalotomy, and Cingulotomy are revisited. Ablative procedures have a limited role in the management of chronic non-cancer pain, but they continues to help patients with refractory cancer-related pain. Another ablation lesion has been named and excluded, due to lack of current relevance. Peripheral Nerve, Spine Cord, and the principal possibilities of Deep Brain and Motor Cortex Stimulation are also revisited. Regarding electrical neuromodulation, patient selection remains a challenge.

Efficacy of Sphenopalatine Ganglion Radiofrequency in Refractory Chronic Cluster Headache

BACKGROUND

In the literature, there are only short series of radiofrequency of the sphenopalatine ganglion (SPG) to treat chronic refractory cluster headache (CCHr) with variable results. Furthermore, there is no consensus on which methodology to use: radiofrequency ablation (RFA) or pulsed radiofrequency (PRF).

METHODS

We conducted a prospective analysis of 37 patients with CCHr who underwent RFA or PRF of the SPG in our center between 2004 and 2015.

RESULTS

The mean age of the patients was 40 years (range, 26-59 years). PRF was performed in 24 patients, and RFA was performed in 13 patients. A total of 5 patients (13.5%) experienced complete clinical relief of both pain and parasympathetic symptoms, 21 patients (56.8%) had partial and transient relief, and 11 patients (29.7%) did not improve. There was no evidence of significant superiority of one radiofrequency modality over the other (P = 0.48). There were no complications associated with the technique. The passage of time tended to decrease the efficacy of both techniques (P < 0.001). The mean follow-up was 68.1 months (range, 15-148 months). To our knowledge, this is the series with the largest number of patients and the longest follow-up period published in the literature.

CONCLUSIONS

Radiofrequency of the SPG is a safe, fast, and partially effective method for the treatment of CCHr. Given its low rate of complications and its low economic cost, we think it should be one of the first invasive treatment options, prior to techniques with greater morbidity and mortality, such as neuromodulation.

Anodal frontal tDCS for chronic cluster headache treatment: a proof-of-concept trial targeting the anterior cingulate cortex and searching for nociceptive correlates

BACKGROUND

Percutaneous occipital nerve stimulation (ONS) is effective in refractory chronic cluster headache (rCCH) patients. Responders to ONS differ from non-responders by greater glucose metabolism in subgenual anterior cingulate cortex (sgACC). We reasoned that transcranial direct current stimulation (tDCS), a non-invasive approach, might be able to activate this area and thus improve rCCH patients. Our objective was to explore in a pilot trial the therapeutic potential of tDCS (anode at Fz, cathode over C7) and its possible effects on pain perception, frontal executive functions and mood in rCCH patients.

METHODS

Thirty-one patients were asked to apply daily 20-min sessions of 2 mA tDCS for 4 or 8 weeks after a 1-month baseline. CH attacks were monitored with paper diaries. The primary outcome measure was change in weekly attacks between baseline and the last week of tDCS. Twenty-three patients were available for a modified ITT analysis, 21 for per-protocol analysis. We also explored treatment-related changes in thermal pain thresholds and nociceptive blink reflexes (nBR), frontal lobe function and mood scales.

RESULTS

In the per-protocol analysis there was a mean 35% decrease of attack frequency (p = 0.0001) with 41% of patients having a ≥ 50% decrease. Attack duration and intensity were also significantly reduced. After 8 weeks (n = 10), the 50% responder rate was 45%, but at follow-up 2 weeks after tDCS (n = 16) mean attack frequency had returned to baseline levels. The treatment effect was significant in patients with high baseline thermal pain thresholds in the forehead (n = 12), but not in those with low thresholds (n = 9). The Frontal Assessment Battery score increased after tDCS (p = 0.01), while there was no change in depression scores or nBR.

CONCLUSION

tDCS with a Fz-C7 montage may have a preventive effect in rCCH patients, especially those with low pain sensitivity, suggesting that a sham-controlled trial in cluster headache is worthwhile. Whether the therapeutic effect is due to activation of the sgACC that can in theory be reached by the electrical field, or of other prefrontal cortical areas remains to be determined.