For patients whose headaches start in the temporal region, two 1.5 cm incisions are made in the temples, and a segment of the zygomaticotemporal branch of the trigeminal nerve is resected. At times, segments as long as 3 cm are removed. For patients whose headaches start in the occiput, a 4 cm midline occipital incision is made in order to resect a 1 cm × 2.5 cm portion of the semispinalis

capitis muscle that is medial to the greater occipital nerve. The nerve is then shielded using a subcutaneous flap to isolate it from surrounding muscles. If there is contact between the occipital artery Selleck Fostamatinib and occipital nerves, the artery is at times also resected.[6, 7] From a strictly procedural analysis standpoint, if the theory behind these procedures is that nerve compression is serving as a trigger for migraines, it is unclear why branches of the trigeminal nerve are being resected rather than decompressed for patients whose headaches start in the temporal region. Based on the trigeminal neuralgia literature, it is clear that procedures that involve damaging or destroying a peripheral nerve can lead to numbness, paresthesias, dysesthesias, and even worsening of preoperative pain.[8, 9] As part of the presurgical evaluation, a physical examination including palpation of the potential surgical site is performed. For patients with an intranasal trigger zone, an intranasal examination is performed to look for

abnormalities such AZD6244 solubility dmso as a deviated septum or enlarged turbinates. As part of the surgical evaluation, BTX injections (25 units) or nerve blocks are performed in the frontal, temporal, or occipital region based on the location of headache onset as a screening tool to help determine surgical candidates,[7] but such screening tools are flawed from a functional standpoint. It is important to note that not all surgeons use either of these modalities for screening purposes, and some surgeons may proceed with surgery even if neither of these screening tools yields positive outcomes. BTX

injections inhibit the release of acetylcholine, Obatoclax Mesylate (GX15-070) leading to chemical denervation and muscle paralysis. Although this paralysis could theoretically transiently alleviate suspected nerve compression, BTX is likely effective for the treatment of migraines through other mechanisms as well, which would create false positive indicators for surgical screening purposes. BTX blocks the transmission of γ-motor neurons to the muscle spindles, which relay afferent muscle stretch information to the central nervous system. This reduced transmission may decrease hyperactive muscle contractions resulting in a reduction of pain.10-13 In addition, BTX affects some nerve terminals that contain substance P, calcitonin gene-related peptide, somatostatin, enkephalins, norepinephrine, adenosine triphosphate, neuropeptide Y, and nitric oxide,13-15 which play varying roles in the pathophysiology of migraine.