Sustained long-term effect of occipital nerve stimulation in MICCH

In a prospective follow-up of the ICON study, occipital nerve stimulation (ONS) appeared a safe, well-tolerated, and effective long-term treatment of medically intractable chronic cluster headache (MICCH). Subjective improvement was reported, even when the attack frequency was not reduced.

The previously published ICON study randomised 131 patients with MICCH to 24 weeks of treatment; 65 to 100% ONS and 66 to 30% ONS [1]. Both ONS intensities substantially reduced attack frequency and were safe and well tolerated. At the EHC 2022, Dr Roemer Brandt (Leiden University Medical Centre, Netherlands) presented the long-term effectiveness and safety outcomes for exclusively the Dutch participants [2]. The total follow-up period was 8 years (2012–2020). The participants completed 6-monthly questionnaires addressing weekly attack frequency, subjective improvement, adverse events, and willingness to recommend this treatment to other patients. Missing values for log-transformed attack frequency were imputed for up to 5 years of follow-up.

The 88 Dutch participants who had provided informed consent were followed for ≥2 years (mean follow-up was 4.2 years) unless the device was prematurely removed. The number of active participants was 73 (83%) after 2 years, 60 (68%) after 3 years, 32 (36%) after 5 years, and 3 (3%) after 8.5 years. In the original ICON study, 49 of 88 (56%) participants included in the follow-up were ≥50% responders. During follow-up, 35 of these 49 (71%) retained this response, while 15 of the original 39 (38%) non-responders became ≥50% responders during at least half the follow-up period.

The pooled geometric mean weekly attack frequency, which was 16.2 (95% CI 14.4 - 18.3) at baseline, remained significantly lower after 1–5 years:

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  • after 1 year: 4.2 (2.8–6.3);
  • after 2 years: 5.1 (3.5–7.6);
  • after 5 years: 4.1 (3.0–5.5).

Sum scores of the 36-Item Short Form Survey (SF-36) for physical health were 50 at baseline (n=128), 60 after 3 years (n=58), and 61 after 6 years (n=25). Sum scores for the SF-36 mental health were 63 and 70, respectively. At the most recent follow-up, 69 of 88 patients (78%) reported a subjective improvement from baseline; 70 of 88 (81%) would recommend ONS to other patients. In 112 of 122 (92%) hardware-related events occurring in 44 of 88 participants (50%), additional surgery was required. No predictive factors for effectiveness 3 years after ONS implantation could be identified.

1. 
   
   1. Wilbrink LA, et al. Lancet Neurol. 2021;20(7):515–25.
   2. Brandt R. Long-term effectiveness and safety of occipital nerve stimulation in medically intractable chronic cluster headache: a prospective follow-up study of the randomised controlled ICON trial. Poster P24, EHC 2022, 07–10 December, Vienna, Austria.

 

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Posted on 5 January, 20238 February, 2024