PERCUTANEOUS ELECTRICAL NERVE STIMULATION (PENS) THERAPY FOR REFRACTORY PRIMARY HEADACHE DISORDERS

Dr Mark Weatherall

Saturday, April 08, 2017

Methods

Our aim was to demonstrate whether percutaneous electrical nerve stimulation (PENS) therapy has a role to play in the management of refractory headache disorders. A retrospective review of the records of 36 patients who have been treated with supraorbital or occipital PENS therapy at our centre between September 2012 and June 2016 was undertaken. Follow-up data was available for 33 patients. Of these, 26 had a primary headache diagnosis, of whom 14 had chronic migraine (CM), 9 had chronic cluster headache (CCH), 2 had new daily persistent headache (with migrainous features), and one had hemicrania continua. The secondary headaches comprised occipital neuralgia, cervicogenic headache, and trigeminal neuropathy.


Technical details

PENS was given using Algotec. disposable 21 gauge PENS therapy probes (50mm ) to the occipital nerve ipsilateral to the pain (or bilaterally in cases of bilateral pain). In some cases supraorbital PENS was tried on a second or subsequent occasion if the patient had failed to respond to occipital stimulation. Stimulation was delivered at 2 Hz/100 Hz, at 3 cycles/second, between 1.2-2.5 V depending on patient tolerability, for 25-28 minutes. No immediate complications were recorded during stimulation, apart from one patient who

experienced pain during stimulation, and in most cases the treating neurosurgeon (DN) recorded good coverage and radiation of effect during stimulation.


Results

Six out of the nine patients with CCH improved significantly (see the table below); these patients had previously failed to respond to between two and eight oral preventative medications, and had at best experienced temporary benefit from nerve blocks with local anaesthetic agents. In all patients with CCH, PENS therapy was well tolerated, with no significant adverse events reported. One patient with CCH reverted to the episodic form of the disorder; this improvement has been maintained for more than two years following the cessation of therapy. Only three of the patients with CM experienced any noticeable benefit with PENS therapy; one patient with CM experienced pain during stimulation, two patients with CM experienced severe neck pain, and three patients with CM experienced an

exacerbation of their condition lasting days to weeks. These adverse effects are possibly due to the presence of significant allodynia, not improved by PENS therapy.


Conclusion

PENS therapy shows great potential as a relatively non-invasive, low-risk, and inexpensive component of the treatment options for refractory primary headache disorders, particularly chronic cluster headache. Further trials of the technique in this debilitating condition are warranted.




PENS is a minimally invasive therapy, which enables the physician to determine whether a patient is likely to benefit from an implanted stimulation device, although for some patients it may also provide ongoing pain management, thereby avoiding the need for more invasive therapies, with their attendant risks. There are also patients for whom an implanted device is not appropriate and in these cases PENS therapy offers an alternative where other less invasive or pharmacological modalities have failed.