Chronic cluster headache (CCH) is a debilitating headache disorder, often refractory to medical and interventional management. Bilateral occipital nerve stimulation (ONS) has shown effectiveness in treating intractable CCH; however, studies have reported high rates of device-related complications. Recently, temporary 60-day peripheral nerve stimulation (PNS) has demonstrated prolonged pain relief beyond the treatment period in various chronic pain syndromes.1, 2 We present a case of CCH with meaningful and sustained improvement following a bilateral 60-day temporary ONS. We attest that written informed consent for publication was obtained from the patient. The patient was a 68 year old male with a past medical history notable for left-sided Horner's syndrome at the age of 26 and a history of smoking. He was initially diagnosed with episodic cluster headache at the age of 45 years, which progressed to CCH by the age of 62 years. There was no personal history of migraine or head trauma. The patient's typical headache attacks were characterized by severe left-sided orbital and temporal pain rated at 10/10 on the visual analogue scale, accompanied by ipsilateral conjunctival injection, nasal congestion, photophobia, phonophobia, and agitation. He experienced 1–3 attacks per day, lasting anywhere from a few to 45 min, depending on oxygen treatment response. At times, headaches would increase to a frequency up to 10 times per day. Attacks occurred predominantly at night and were occasionally triggered by alcohol consumption. Contrast-enhanced brain MRIs prior to presentation for ONS were without evidence of structural abnormalities. Over the years, the patient received multiple treatments. Abortive therapies included oxygen and eletriptan 40 mg, which provided effective pain relief, whereas sumatriptan injections and nasal dihydroergotamine had little to no effect. Preventive treatments included verapamil, lithium, topiramate, gabapentin, levetiracetam, baclofen, riboflavin, indomethacin, divalproex sodium (Depakote), melatonin, monthly galcanezumab, and tizanidine. He was also treated with several courses of prednisone throughout the years. Additional interventions included every 12 weeks onabotulinumtoxinA injections following the Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) protocol, occipital nerve blocks, and fluoroscopically guided sphenopalatine ganglion blocks, all of which produced only short-term relief. A 1-month trial of transcutaneous vagus nerve stimulation was unsuccessful. Prior to bilateral ONS lead placement, he was treated and maintained on galcanezumab 300 mg monthly, verapamil 80 mg three times daily, lithium 300 mg three times daily, topiramate 200 mg twice daily, and onabotulinumtoxinA injections. At the age of 68 years, the patient underwent bilateral temporary PNS using a SPRINT PNS (SPR Therapeutics, Cleveland, OH, USA) system targeting the greater occipital nerves. The neurostimulator leads were placed with fluoroscopic guidance following the same technique outlined by Gutierrez et al.3 During intraoperative paresthesia mapping, he had good coverage in the bilateral occipital dermatomes. His symptoms gradually improved during the 60-day treatment period in terms of headache frequency, reaching 5 headache-free days prior to lead removal. During the course of treatment, he continued to have paresthesia over the left occipital dermatome, with device settings ranging from 64 to 82. However, on the right side, he had some motor stimulation of the sternocleidomastoid resulting in torticollis; as a result, stimulation on the right side was kept at lower amplitude (23) during the first week. At the end of the 60-day treatment, the leads were removed with the left lead intact, but a small fragment <1 cm in length was retained of the right lead, which did not affect MRI compatibility and so was left in place. Otherwise, there were no adverse events, and the patient tolerated treatment well with minimal procedural discomfort. At the conclusion of treatment, the patient's headache frequency had decreased to four episodes per month. This improvement persisted for at least 6 weeks following device removal. The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference and Sleep Disturbance T-scores mild impairment at baseline to within normal limits 3 months postimplant. In the 3 years following treatment, the patient continued preventive therapy with galcanezumab, lithium, topiramate, and verapamil. He was able to de-escalate preventive treatment where the onabotulinumtoxinA injections were stopped. Over time, he experienced progressively fewer attacks and responded better to oxygen. He ultimately became headache-free for over a year, with only two attacks reported in the final year of follow-up. The benefit of permanent ONS in CH has been recognized through both prospective and long-term observational studies.4 A study by Gutierrez et al. employed 60-day ONS for occipital neuralgia, and cervicogenic headache showed sustained improvement not only in occipital distribution pain but also pain in the orbital/supraorbital and frontotemporal areas,3 regions that overlap with those affected in CH. The proposed mechanism by which ONS alleviates CH symptoms involves the convergence and interaction of cervical, somatic trigeminal, and dural trigeminovascular afferents onto second-order nociceptive neurons within the brainstem.4 We believe that temporary 60-day ONS can exert this therapeutic effect without the need for permanent implantation of an internal pulse generator (IPG). This is supported by prior studies in which patients treated with ONS utilizing an implanted IPG for preventive treatment have had devices explanted after they were either “doing well” or when CCH reverted back to episodic CH and remained episodic CH in long-term follow-up.4 We suspect that the duration of treatment needed to result in sustained neuroplastic changes is longer than the standard duration of 7–10 days used for traditional neurostimulator trials but can be achieved within 60 days of treatment in most patients with CCH. The risks of temporary PNS for 60 days are considerably lower than what has been reported in ONS with permanent IPG implantation.3 This case serves as proof of concept for the use of temporary, bilateral 60-day ONS as a transitional treatment in CCH or for extended trialing to guide patient selection for permanent ONS implantation with an IPG. Whereas the efficacy of permanent ONS with an IPG has been previously shown, this case represents a novel minimally invasive approach for long-term symptom relief with a device designed to treat peripheral nerves that inherently has lower rates of device-related complications than the devices used in prior studies investigating ONS for treatment of CH. Further prospective studies are warranted to evaluate its long-term efficacy and broader applicability in CH. Keshet Pardo: Writing – original draft. Christopher J. Boes: Data curation. Narayan R. Kissoon: Conceptualization; writing – review and editing. Narayan R. Kissoon has consulted for Vertex and has received research support paid to the institution from Shiratronics, Nevro, and Novo Nordisk. Dr. Kissoon has received royalties from UpToDate, Inc. Keshet Pardo and Christopher J. Boes have no disclosures.
Pardo et al. (Wed,) studied this question.