Ultrasound Guided Radiofrequency Ablation of Proximal Greater Occipital Nerve in Primary Occipital Neuralgia

Overview

The International Headache Society (IHS) defines occipital neuralgia, as a unilateral or bilateral paroxysmal, shooting, or stabbing pain in the posterior region of the scalp, in the distribution of the greater occipital nerve (GON), lesser occipital nerve (LON), or third occipital nerve (TON). The condition is occasionally accompanied by diminished sensation or dysesthesia in the affected area and is frequently associated with tenderness over the involved nerves. The majority of cases with occipital neuralgia are idiopathic, with no clearly defined anatomical cause. First, conservative treatment approaches including medication and physical therapy are frequently used. When conservative measures fail to alleviate occipital neuralgia, interventional treatments such as local occipital nerve anesthetic and corticosteroid infiltration, botulinum toxin A injection, occipital nerve subcutaneous neurostimulation or occipital nerve radifrequency treatment may be used.

Radiofrequency ablation (RFA) is a thermal ablative procedure commonly used to treat chronic neurogenic pain by targeting peripheral nerves or dorsal root ganglion by destructing the tissue at a temperature ranging beteen 60-80 C. The pain is interrupted by destructing the nerve with Wallerian dejeneration. The pain interruption period is longer and stronger than pulsed radiofrequency. GON is a pure sensory nerve, RFA may be an alternative therapy option for occipital neuralgia. By ultrasound (US) guidance, at C2 level , GON lies between semispinalis capitis muscle and inferior oblique muscle. The GON is well identified here and can be easily targeted rather than trying to identify the terminal subcutaneous branches at the nuchal line. Diagnostic blockade was administered to patients who did not respond to conventional therapy. If the response to diagnostic blockade was greater than 50%, RFA was instituted one week later. Patients' headache intensity was measured using the Numeric Rating Scale-11 Pain Score (NRS) at each appointment (pre-intervention, 1-3-6, and 12 months post-intervention). At each appointment, an evaluation of headache disability was conducted using the Headache Impact Test (Hit-6) and the number of headache days per month. The efficacy of the treatment was defined as NRS\<4 at the twelveth month. During the initial evaluation, patients' demographic details and headache symptoms were thoroughly questioned. In accordance with the Turkish National Headache and Pain Research Association's recommendation, patients were asked to keep up headache diaries for the duration of the treatment and all subsequent appointments. The headache intensity, headache disability and the number of headache days in a month, as well as the use of rescue medication, including NSAIDs and paracethamol, were determined from the diaries and discussed with the patient at each session.