Headache Table 1: Diagnostic Criteria for Cluster Headache3
A At least five headache attacks fulfilling criteria B–D B Severe or very severe unilateral orbital, supraorbital and/or temporal pain lasting 15–180 minutes if untreated
C
Headache is accompanied by at least one of the following symptoms ipsilateral to the pain: • conjunctival injection or lacrimation • nasal congestion and/or rhinorrhoea • eyelid oedema • forehead and facial sweating • miosis and/or ptosis • a sense of restlessness or agitation
D Attacks have a frequency from one every other day to eight per day E Not attributed to another disorder Table 2: Medically Intractable Cluster Headache8
Failed an adequate trial of regulatory approved and conventional treatments according to local national guidelines Adequate trial: • appropriate dose
• appropriate length of time • consideration of medication overuse Medication failed due to:
• no therapeutic or unsatisfactory effect • intolerable side effects • contraindications to use
Failure of at least four classes, where two should come from 1–3: 1. verapamil 2. lithium
3. methysergide 4. melatonin 5. topiramate 6. gabapentin
to the episodic form,23 natural history.
so a procedure should not be less safe than the Peripheral Approaches
A number of structures have been suggested as peripheral targets of stimulation in CH. These include the occipital nerve, which will be dealt with in detail below as there are now a number of studies available, the ophthalmic branch of the trigeminal nerve (n=1),24 stimulation (n=6)25
and higher cervical stimulation (n=1).26
relative data and promise, occipital nerve stimulation (ONS) is dealt with in more detail below.
Occipital Nerve Stimulation
Initial interest in the use of ONS to treat headache dates from Weiner and Read,27
who reported a series of cases of intractable occipital neuralgia responding to ONS. Detailed phenotyping of these cases in association with a functional imaging study demonstrated that almost all patients had chronic migraine.28
What was remarkable in the ONS
patients studied using functional imaging was that the therapy, while effective in terms of pain, did not seem to alter the brain activation of areas considered to be important in migraine. Instead it changed thalamic processing. Taken together with experimental data collected by the authors of this paper,29–31
it was reasoned that ONS may be helpful
in selected patients with other primary headache disorders. It seems likely, given that peripheral distribution of the pain does not predict the outcome of stimulation, that ONS has an important central effect on the brain.32
98
procedure had sufficient benefit to recommend the procedure to others and to make it an option for other neuromodulation approaches.33
Long-
term experience over more than two years demonstrated that device dysfunction almost always led to the return of attacks.34
It thus seems
unlikely that the useful effect is a prolonged placebo, although much more needs to be done to establish the mechanism of the useful effect.
Central Nervous System Approaches – Deep Brain Stimulation
Recognising that all invasive treatments bear the risk of severe side effects, international guidelines for patient selection based on expert consensus were published.35
The criteria for the use of deep
brain stimulation (DBS) include only considering patients with all of the following: CCH and strictly unilateral attacks without side shift; a normal psychological profile; and no medical/neurological condition contraindicating DBS, such as epilepsy or stroke. Only patients who are medically intractable should be considered for DBS. Considering that more than 50 patients have been operated on and the results published,36
with an average of 50–70% showing a significant positive response, the question arises of whether it is possible to formulate predictive indicators of which patients will respond to hypothalamic DBS in CH.
Defining the Target Point
Neuroimaging with positron-emission tomography (PET) shed light on the genesis of CH, documenting the link between activation in the hypothalamic grey ipsilateral and pain in CH.38
These areas are not
simply involved in the response to first-division nociceptive pain impulses but are inherent to each syndrome, probably in some permissive or dysfunctional role.9,39
Furthermore, using high-resolution
structural 3D magnetic resonance images and voxel-based morphometry, a significant structural difference in grey matter density of the hypothalamus was found in patients with CH compared with healthy volunteers.40
The target point for DBS in CH was chosen based on clinical considerations and functional studies, particularly neuroimaging, which revealed the crucial role of the posterior hypothalamic region in CH.37
vagus nerve Given its
the data suggest a crucial involvement of this hypothalamic area, at least in generation of the acute CH attack. Initially, it was thought that the hypothalamic region at the posterior inferior border was activated only in CH. Subsequently, it was shown that this hypothalamic area is also activated during short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing (SUNCT),43,44
The co-localisation of morphometric and functional changes demonstrates the precise anatomical location for a probable central nervous system lesion in CH. Given that this area is involved in circadian rhythms, sleep–wake cycling41 system,42
and control of the autonomic paroxysmal hemicrania45 and hemicrania continua.46 Despite
this, a second study found no activation in the hypothalamus in hemicrania continua in a single patient without cranial autonomic features.47
For DBS the electrode is usually implanted stereotactically in the left posterior hypothalamus/anterior periventricular region of the triangle of Sano, according to the co-ordinates published.38
This area
does not correspond to a specific anatomical entity and there is no consensus as to whether it is part of the posterior hypothalamus or tegmentum, or even the anterior periventricular grey matter. Two sets of stereotactic co-ordinates have been described:
• Six out of the eight patients initially undergoing this
those published by Leone and colleagues: x=2mm lateral to the midline, y=6mm behind the mid-commissural point and z=8mm below the commissural plane;48
and EUROPEAN NEUROLOGICAL REVIEW
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116