Sphenopalatine Ganglion (SPG) Blocks have been used for relief of Chronic Daily Headaches, Migraines, Cluster Headaches and other Trigeminal Autonomic Cephalgias as well as for TMD disorders.  Recent research shows effectiveness in the obstetric world for post Dural Puncture Headache and associated back ache.
This abstract is important because it shows the effectiveness of the SPG for Chronic Region Pain Syndrome (CRPS) in the legs.  This article also discusses that the patient was taught how to Self-Administer SPG Blocks (SASPGB)
 The use of Self-Administration allows the patient to control their pain .
The second abstract discusses upper and lower limb pain associated with migraines.  This meets a description of Scluder’s Neuralgia or Sphenopalatine Ganglion Neuralgia.
Arch Phys Med Rehabil. 2005 Feb;86(2):335-7.
Complex regional pain syndrome involving the lower extremity: a report of 2 cases of sphenopalatine block as a treatment option.

We report 2 cases of complex regional pain syndrome (CRPS) involving the lower extremity; in both, a sphenopalatine ganglion (SPG) block was performed as part of a pain management program. In the first case, a woman in her late twenties presented with CRPS in the left lower extremity that was inadequately controlled with typical oral medications. Sympathetic block of the extremity did not provide significant pain relief. However, a noninvasive sphenopalatine block with 4% tetracaine resulted in a 50% reduction in pain level. The patient was shown how to self-administer the sphenopalatine block and was provided with exercises and therapy to help improve her functional status. The second case involved a woman in her mid forties with CRPS in the right lower extremity that was partially controlled with oral medications. The patient experienced a 50% reduction in pain level when SPG block with 4% tetracaine was given. Further study is needed to determine the effects of SPG blocks on symptoms related to chronic regional pain syndrome.

Headache. 1990 Feb;30(3):138-41.
Migrainous limb pain. A historical note.

Upper and lower limb pain associated to attacks of migraine or cluster headache has been mentioned by many authors since the early descriptions of Liveing, Gowers and Jeliffe. The symptom was also described by Sluder as part of the syndrome of “sphenopalatine ganglion neuralgia.” Several authors in the 1920’s and 1930’s including Cushing and Harris reported cases currently classifiable as migraine or cluster headache with limb pain, but did not accept the mechanisms for pain proposed by Sluder. The scarcity of more recent reports suggests that many patients with migrainous limb pain may be assumed to have other causes for this pain.

Cephalalgia. 2010 Mar;30(3):360-4. doi: 10.1111/j.1468-2982.2009.01919.x.
Sluder‘s neuralgia: a trigeminal autonomic cephalalgia?

The objective was to formulate distinctive criteria to substantiate our opinion that Sluder‘s neuralgia and cluster headache are two different clinical entities. A systematic review was carried out of all available, original literature on Sluder‘s neuralgia. Pain characteristics, periodicity and associated signs and symptoms were studied and listed according to frequency of appearance. Eleven articles on Sluder‘s neuralgia were evaluated. Several differences between Sluder‘s neuralgia and cluster headache became evident. Based on described symptoms, new criteria for Sluder‘s neuralgia could be formulated. Sluder‘s neuralgia and cluster headache could possibly be regarded as two different headache syndromes, and Sluder‘s neuralgia could be a trigeminal autonomic cephalalgia.