**5. Indications and results for specific chronic headache disorders**

#### **5.1. Cluster headache (CH)**

*4.2.3. Great auricular nerve stimulation (GANS)*

128 Transcranial Magnetic Stimulation in Neuropsychiatry

*4.2.4. Supraorbital nerve stimulation (SONS)*

*4.2.5. Cervical spinal cord stimulation (SCS)*

*4.2.6. Hypothalamic deep brain stimulation (hDBS)*

to decrease the chance of haemorrhages [49, 52].

to the cervical spinal cord until its distal tip is at the C2

Further studies are needed.

clavicular area [46].

of patients [50].

reported [50].

Pain relief was reported using this technique in a single case of persistent MTHI-Ha 90% [37].

The first case was reported in 2009 in the treatment of CH [36]. In this disorder, SONS produced more than 50% pain reduction in 71% of the patients [19, 36, 90]. In a series of five patients with TACs, it improved the pain in all of them, but the series is too short to draw any

The electrode is introduced in the epidural space at the upper thoracic level and advanced

inserted. The leads are connected to a subcutaneous impulse generator inserted at the infra-

SCS has been used in CM [46, 47], SUNA [54], CH [45, 64], and MTBI-HA [48], reducing the headache frequency and/or intensity by ≥50% in 71% of the patients [45–47]. In CM, it improves the headache by >30% in 50% of the cases [46, 47, 102]. The AEs are frequent (71%) and usually require system explant and replacement in a second surgery [102]. Among these

hDBS was introduced in 2000 to treat drug-resistant CH [61]. It is useful in many types of chronic headache disorders like HC, CH, SUNCT/SUNA, and in TACs [4, 50]. In chronic CH, it results in reduction of ≥50% of the attacks in 60% of the patients [5, 40, 50, 52]. The response rate in HC and SUNA is 82% [49]. In TACSs, the improvement rate is >50% in 69.9%

AEs include incision site pain, subcutaneous dislodgement of the impulse generator, transient gaze disturbance (oscillopsia, diplopia), autonomic disturbances, myosis, dizziness, wound infection, cervical dystonia, intracranial haemorrhage, and lead disconnection or rupture [40, 49, 52]. Many of these complications require system explant [49]. hDBS is reserved for those very few cases, in which everything else has failed as death has been

The target was initially in the posterior hypothalamus [103, 104], but other areas have also been used like the mesencephalic grey substance, the red nucleus, the fasciculus retroflexus, the dorsal longitudinal fasciculus, the ansa lenticularis, the medial longitudinal fasciculus or the medial thalamus superficialis [104]. In the latest years, the ventral tegmental area is used

level. One or two electrodes are

conclusions [19]. It can be used alone or associated with ONS [14, 15, 19, 90].

AEs are infections (13%) and lead rupture or migration (17%) [45–47, 89].

CH consists of bouts of unilateral periorbital pain lasting between 15 minutes and 3 hours that follow an annual pattern [105]. It is considered as the most painful headache type, with 0.12% prevalence. About 10% of the cases cannot be controlled with medical treatment [34]. CH has two variants: chronic and episodic [106]. In the episodic, headache periods alternate with others of remission, and the attacks last between 7 days and 1 year with a pain free period lasting at least 1 month [105]. The chronic variant represents 10–15% of the cases [34, 86] and has free pain periods shorter than 1 month or attacks that are present nonstop through at least 1 year [105].

Percutaneous VNS has been used in the acute treatment of the chronic variant of CH with a higher than 50% pain reduction in 40% of the patients [33, 42, 81, 107]. Although not universally effective, it is minimally invasive and with very minor and reversible AEs.

Both ONS [25, 26, 34] and SPGS [40–43, 73] are the first options among the invasive techniques [5, 86]. About 70% of patients respond to these treatments with 48% of excellent responders [25, 34]. ONS together with SONS has been applied with >50% pain reduction in 71% of the patients [90]. Cervical SCS has also been used with some success [102]. hDBS should be left as the very last resource as its complications are more severe and potentially life threatening [5, 52].

#### **5.2. Hemicrania continua (HC)**

It is a continuous and unilateral headache (it only affects one side of the head), associated autonomic symptoms and episodes of increased headache intensity [105]. Indomethacin is the drug of choice, but some patients do not tolerate it due to side effects like hypertension, gastrointestinal problems (particularly when combined with aspirin), vascular events, or bronchial spasms [83]. In a single case, it was found to respond to noninvasive percutaneous VNS [83]. Others tried repetitive sphenopalatine ganglion block [108]. The data are not statistically significant, and no definite conclusions can be drawn.

#### **5.3. Chronic migraine (CM)**

CM is described as having migraine headaches 15 or more days in every month [99]. Worldwide, it is the seventh cause of disability [109]. It affects 2–5% of the adult population [3, 105, 110].

The transcranial stimulation has contradictory results, so no recommendations can be offered [9]. The cervical percutaneous VNS shows promising but moderate results, better in the episodic than in chronic variant [20, 111]. Transcutaneous SONS reduces the number of attacks but not its intensity [18, 111]. Much more efficient is the ONS via implanted electrodes [5, 24, 29, 46], with a success rate of 65.4% in 67.9–80% of the cases [29, 95]. Unfortunately, 70% of the patients suffer AEs, 40.7% of which require a new surgical procedure [29]. Some have combined the ONS with the SONS with ≥50% pain reduction in >70% of the patients [14]. The SCS has also been applied with 30% pain reduction in 50% of the cases [46].

**7. Conclusions**

Although the immense majority of chronic headache disorders can be controlled with pharmacological means, there is a subset of patients that are refractory to all of them. A thorough diagnosis of the specific headache subtype is essential to provide an effective treatment. For those few refractory patients to the current available drugs, there are other treatment possibilities. We have now a wide array of noninvasive techniques that can be tried as a first attempt. In case of failure, surgically implanted stimulating systems can be of help. We should choose the more suitable option to the specific headache variant, keeping in mind the effectivity possible incidence of AEs of each treatment. hDBS should be considered the very last resource, as

Chronic Headache and Neuromodulation http://dx.doi.org/10.5772/intechopen.72150 131

it is associated with some serious AEs and potentially to death.

**Appendices and nomenclatures**

AE Adverse event

CH Cluster headache CM Chronic migraine

HC Hemicrania continua

HM Hemiplegic migraine

ONS Occipital nerve stimulation

SONS Supraorbital nerve stimulation

symptoms

VNS Vagus nerve stimulation

SPGS Sphenopalatine ganglion stimulation

injection and tearing

TACs Trigeminal autonomic cephalagias TMS Transcranial magnetic stimulation

SCS Spinal cord stimulation

GANS Great auricular nerve stimulation

hDBS Hypothalamic deep brain stimulation

MTHI-H Mild traumatic head injury-related headache

SUNA Short-lasting unilateral neuralgiform headache attacks with autonomic

SUNCT Short-lasting unilateral neuralgiform headache attacks with conjunctival

tSNS Noninvasive transcutaneous supraorbital neurostimulation

#### **5.4. Hemiplegic migraine**

It is a very severe migraine variant, refractory to most known therapies and that often evolves to a very debilitating state. It has been treated with combined SONS and ONS with a 92% average decrease in the number of attacks [15]. The number of cases is limited, so further studies are needed.

#### **5.5. Trigeminal autonomic cephalalgias (TACs)**

TAC is a group of headache disorders characterised by unilateral headache accompanied by cranial autonomic symptoms. Although SONS has been attempted [19], ONS is the first option [27], reserving the hDBS to the most recalcitrant cases [49, 50, 52].

### **5.6. Short-lasting unilateral Neuralgiform headache attacks with autonomic symptoms (SUNA) and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)**

These consist of primary headache attacks associated with cranial autonomic dysfunction. In refractory cases, bilateral ONS induced a 69% pain improvement in 77% of the patients [93, 94]. Deep brain ventral tegmental area stimulation achieved a 78% headache rate improvement in almost all patients but with frequent AEs that at times required to explant the system [49].

#### **5.7. Mild traumatic head injury-related headache (MTHI-H)**

MTHI-H represents about 4% of the chronic headaches [112]. Transcranial magnetic stimulation has shown a 57% improvement in the intensity and frequency in this disorder [11–13]. SCS or GANS [37] stimulation has been used, stimulating the left prefrontal cortex [11]. In both cases, there was a 90% headache frequency reduction. Unfortunately, only two case reports exist, and no conclusions can be drawn.
