1. 2014;17;29-41Occipital Nerve Stimulation in the Treatment of Medically Intractable SUNCT and SUNA
   Prospective Evaluation
   Giorgio Lambru, MD, Paul Shanahan, MB, BCh, BAO, MRCP, Laurence Watkins, MD, FRCS, and Manjit Singh Matharu, MBChB, MRCP, PhD.

BACKGROUND: Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) or with cranial autonomic symptoms (SUNA) are primary headaches characterized by frequent attacks of severe headaches in association with cranial autonomic features. Patients with chronic SUNCT or SUNA have unremitting symptoms that necessitate prolonged use of medical preventive treatments, many of which are prone to causing side effects. They can be medically intractable, in which case neurally destructive or cranially invasive surgical treatments can be offered, though these have hitherto yielded conflicting results. Occipital nerve stimulation (ONS) offers a nondestructive and relatively low risk surgical alternative.

OBJECTIVE: To assess the efficacy and safety of ONS in chronic, medically intractable SUNCT and SUNA patients.

STUDY DESIGN: Prospective open-label study.

METHODS: Nine medically intractable, chronic SUNCT and SUNA patients were implanted with electrodes for bilateral occipital nerve stimulation. Data were collected prospectively for pre- and postimplantation headache characteristics, including frequency, intensity and duration of attacks. Diaries were used to assess headache  improvement.

RESULTS: At a median follow-up of 38 months (range 24–55 months), all but one patient reported substantial improvement. Four patients became pain-free, 3 were almost pain-free (96 – 98% improvement), and one had a marked reduction in attack frequency and severity (81% improvement). After an initial rapid improvement, the maximum benefit of ONS was attained after a lag of a few months. Device malfunction was followed by recurrence or worsening of the attacks within a few days in most patients. Adverse events included lead migration, exposure of the electrode, and pain due to muscle recruitment over the leads. One patient developed hemicrania continua one month after implantation and was successfully treated with indomethacin.

CONCLUSION: ONS appears to offer an effective and safe treatment option, without significant morbidity, for medically intractable SUNCT and SUNA. Given the variable results with cranially invasive or neurally destructive surgery, ONS might be considered the surgical treatment of choice for medically intractable SUNCT and SUNA.