Effects of microvascular decompression of the pterygpalatine ganglion in patients with persistent, drug-resistent, Cluster headache: a pilot study.

Cluster headache (CH) is, although rare, a disorder well known to
otolaryngologists and neurologists. CH is an invalidating condition, the pain
during attacks is often described as excruciating.
The specific cause of CH remains unknown, but several mechanisms have been
suggested to play a role in its etiology. One of the theories is that the
pterygopalatine ganglion (PPG) is the main route for CH and its associated
parasympathetic symptoms. Patients with CH can have adequate pain relief with
farmacological therapy, however, some patients require surgical treatment
because of persistent, drug-resistant CH. Previous studies have shown that
treatment directed against the PPG, such as radiofrequent thermocoagulation,
can be effective in patients with CH.
However, most treatments only provide temporary pain relief, and repeated
surgical procedures are sometimed needed to establish long lasting pain relief.
Examination of the anatomic relations of the PPG reveals that it lies in close
contact with a remarkably tortuous portion of the maxilllary artery along its
course in the pterygopalatine fossa. This fact supports the hypothesis that
vascular compression of the PPG by a loop of the maxillary artery, can account
for some of the manifestations of CH.
Vascular compression syndromes are associated with a variety of other disorders
such as trigeminal neuralgia, and previous studies have shown that these
disorders can be treated succesfully with microvascular decompression (MVD).
Our hypothesis is that microvascular decompression of the pterygopalatine
ganglion may be effective in patients with CH in terms of providing long
lasting pain relief.

Main objective of this study is to assess the effects of MVD in management of
patients with persistent, drug-resistant CH in terms of pain reduction and
improvement of quality of life. More specific: to evaluate if MVD can provide
adequate pain relief and improvement of quality of life, both short and
longterm, in patients with persistent, drug-resistant CH.

A pilot study will be carried out in 6 patients with persistent chronic, drug
resistant CH.
To exclude pathology as a causative factor for the pain and in order to be
prepared for anatomical variations in the involved area, all patients will
undergo CT and MRI or MRA.
All patients will initially be treated with lidocaine nose drops for four
weeks, after which they will undergo MVD of the pterygopalatine ganglion. The
follow-up period after MVD will be six months. Pain relief and improvement of
quality of life will be assessed via questionnaires filled out at inclusion and
at one week, 3 and 6 months follow-up.

Microvascular decompression of the pterygopalatine ganglion by means of
insertion of a piece of temporal muscle between the pterygopalatine ganglion
and the maxillary artery and clipping of the artery itself; to ensure
discontinuation of contact between the pterygopalatine ganglion and the
maxillary artery.

Risks include the standard risks of anaesthesia and the usual risks of sinus
surgery such as intra- and postoperative bleeding due to injury of the artery,
postoperative sinusitis, paraesthesia of the palate and face, oroantral
fistula, dental injury and theoreically entering the orbit. However, these
complication rates are very low.
Burden includes a hospital admission for approximately three days and
undergoing CT and MRI or MRA, as well as taking time to fill out the
questionnaires at inclusion and during follow-up.