Abstract
A review of the most important invasive treatment options for cervicogenic headache is given. The methods are briefly described and discussed.
The invasive procedures used for treatment of cervicogenic headache (CEH) are presented in a schematic manner and reported in Table 1.
Invasive procedures
Nerve blocks can be used diagnostically, as well as therapeutically. Diagnostically, the nerves in question are the greater and lesser occipital nerve, as well as the spinal root, and differential diagnostically also the supra- and infraorbital nerves. The occipital nerve has a great variability in its course. The preferred point to reach it is 2–3 cm below the occipital protuberance and 2–3 cm lateral to the midline. The lesser occipital nerve can be reached as it appears from behind the sternocleidomastoid muscle. The cervical nerve roots can be reached by a frontolateral approach under X-ray surveillance.
Cryo procedures (cryo analgesia) have been used in some centres. The procedure is directed at the greater occipital nerve. After local anaesthesia, a cryosonde is brought close to the nerve and the temperature is reduced to approximately −60–70° for 2–3 min. The result is an analgesia that lasts for approximately 3 months. The procedure must therefore be repeated up to three to four times a year. The success rate is claimed in probable CEH patients to be approximately 60% (H Högström, personal communication).
The RF procedure (radiofrequency procedure) is widely used in parts of the world, for instance in the Netherlands and Australia, and also the US, but it is still a controversial therapy. With the use of a radiofrequency generator, the point of a special RF needle is heated to about 80°, thereby coagulating nerve fibres and probably mostly the pain fibres (1). Lately, an alternative method has been advocated (the so-called pulsed-radiofrequency lesion), where the temperature will not reach more than approximately 45° (2). The target for the RF procedure is most frequently the facet joint, or the nerve innervations of the joint from C2–C3, down to C6–C7, with the aim of reducing the painful stimuli from the joint. Nerve roots and discs are, according to M Sluijter, targets one needs to treat in many instances next to the facet joint, to reach a good result in the individual patient. HG Blume (3) has advocated the coagulation of the suboccipital area at the origo of the trapezius muscle and reported a success rate of approximately 80%. In later years, he adopted the idea of Owen Rogal of RF coagulation of the muscle insertion, especially at the spinous process of the C2 vertebrae. The RF treatment is still controversial as to its efficiency and durability, the reported results ranging from no statistical difference compared with placebo to success rates of up to 80% and durability up to more than 10 years (4).
The first operative decompressive procedure was the decompression of the greater occipital nerve at the penetration of the fascia of the trapezius muscle. The idea was that the nerve was entrapped at this point. The results of the operation were very promising. However, the patients tend to have their pain reappear in approximately 1–2 years (5). Some of our patients in this group were re-operated on, with once again a good result, which was, however, of even shorter duration. U. Rossi (personal communication) has, however, advocated that the nerve should be followed in the depth and liberated even as it penetrates the musculus semispinalis and eventually also as it circles the inferior oblique muscle.
The anterior disc surgery and the foramenectomy are procedures that could be considered where there is encroachment of the spinal root in the vertebral canal, for instance by a disc hernia (6). The anterior approach (Robinson-Smith, Cloward) where the segment is immobilized also results in the immobilization of the facet joint, contrary to the foramenectomy, where the root is decompressed at the dorsal aspect. The candidates for these procedures have mostly also symptoms related directly to the segment in question, represented by shoulder pain and/or irradiating arm pain. So far, the radiating symptoms have been the indication for such an operation in most, if not all, neurosurgical units. However, the results with regard to headache have been shown to be equal to, or even better than, the results regarding the irradiating neck/shoulder/arm pain. A not easily understood aspect is that headache can be abated with these procedures, even performed as low in the neck as the C5–C6 and C6–C7 level.
Ganglionectomy at the C2–C3 level either operatively or by RF procedures has been advocated. Professor Jansen has reported good results in a group of severely affected patients. One objection is, however, that these procedures could result in deafferentation pain.
The stimulation procedures in question are high epidural stimulation (DCS) or direct stimulation to the peripheral nerve (PNS), mostly the greater occipital nerve (7). The epidural stimulation is carried out under local anaesthesia. An electrode is administered cranially in the epidural space as far as possible. Mostly, it is not possible to bring it further up than the C2 level. A test stimulation is carried out. The best results are obtained when stimulation produces a tingling sensation in the pain area. This can be difficult to obtain, because the electrode is not positioned high enough cranially. An alternative approach is to put an electrode in position by an operative procedure. Then the electrode can be placed at the C1 level.
Since 1998, there have been papers appearing about stimulation of the occipital nerve by subcutaneous placement of a stimulation electrode over the occipital nerve. The results so far seem promising (7).
In summary, it can be said that there are many approaches to the treatment of cervicogenic headache directed at different structures. This probably reflects that cervicogenic headache is not a disease, but a syndrome with many aetiological factors and causes.
Conflicts of interest
The author has received support for congress attendance from Medtronic Inc.