Occipital neuralgia is a painful condition characterised by pain originating in the upper neck and back of the head. It radiates from the sub-occipital region over the top or side of the head and behind the eyes. Pain is described as paroxysmal shooting or stabbing in the dermatomes corresponding to the lesser and greater occipital nerves. Hypo- or dysaesthesia in the affected area can accompany the pain.
The main symptom of occipital neuralgia is chronic headaches. It is characterised by severe pain beginning in the upper neck and back of the head. There is often a trigger point sensitive to palpation. It is typically described as sharp, shooting, stabbing and electrical shock in nature. It usually affects one side only, although both occipital nerves can be affected. The pain can radiate towards the eye and can cause sensations of blurred vision. The duration of pain can be varied, lasting several seconds or continuous for hours or days. Other less common symptoms experienced may include, sensitivity to light and sound, slurred speech, difficulty with balance or coordination and nausea or vomiting. The diagnosis of occipital neuralgia can sometimes be mistaken for tension, cluster or migraine headaches.
The typical cause of occipital neuralgia is due to damage to the greater or lesser occipital nerve. This is usually the result of direct trauma or compression of the nerve. Compression of the nerve can be due to vascular, muscular or osteogenic causes. Often there is repeated physical stress on the nerve due to underlying degenerative neck disease and repeated movements of the cervical spine. Muscular entrapment of the occipital nerve can be cause by trapezius, semispinalis capitis or obliquus inferior muscles (Fig.1). It can be accompanied by upper facet joint osteoarthritis. It is important to rule out differentiate causes including tumour, infection and congenital anomalies.
Fig 1: From Waldman S. Interventional Pain Management 2nd Ed., demonstrating the course of the greater occipital nerve in relationship to the posterior neck muscles.
Overall diagnosis is based on characteristic of presenting symptoms. Palpation along the greater or lesser occipital nerve will provoke symptoms of sharp and stabbing pain along the path of the nerve towards the side of head and eyes (Positive Hoffmann’s sign). Often individuals will find it difficult to lie on the back of their head. Investigation undertaken may include an MRI head and cervical spine to rule out sinister causes.
Treatment for occipital neuralgia can be conservative or surgical. Conservative treatment is considered first line and includes rest, heat, physical therapy and pain medications. Pain medications may include anti-inflammatories, non-opioid and opioid based medication or migraine prophylaxis medication. Unfortunately medication treatment is seldom successful. Surgical treatment may include injection of local anaesthetic and steroid along the greater and lesser occipital nerve typically at the trigger point (Fig 2). If proven successful, then consideration can be made for radiofrequency ablation of the nerve along with sub-occipital release. The deep injection associated with the sub occipital release, must be done under image guidance by a specialist, to avoid intra-spinal injection (causing respiratory arrest) or intravascular injection. Less commonly used surgical technique include, neurolysis, micro decompression and occipital nerve stimulator implantation.
Fig 2: Left- Image demonstrating point of needle entry for local anaesthetic and steroid injection for greater occipital nerve. Right- Intraoperative x-ray guidance showing needle inserted along line of greater occipital nerve prior to radiofrequency pulsed ablation.