Page 308 Guide to Pain Management in Low-Resource Settings

296 Steven D. Waldman

the diagnosis of unexplained pain. Furthermore, there up of the fused portion of the seventh cervical and fi rst
are some things that the clinician can do to increase the thoracic sympathetic ganglia. Th e stellate ganglion lies
sensitivity of this technique, which include: anteromedial to the vertebral artery and is medial to
1) Using the reverse diff erential spinal or epidural the common carotid artery and jugular vein. Th e stel-
block, in which the patient is given a high concentration late ganglion is lateral to the trachea and esophagus. Th e
of local anesthetic, which results in a dense motor, sen- proximity of the exiting cervical nerve roots and brachi-
sory, and sympathetic block, and the observation of the al plexus to the stellate ganglion makes it easy to inad-
patient as the block regresses; vertently block these structures when performing stel-
2) Using opioids instead of local anesthetics, which late ganglion block, making interpretation of the results
removes the sensory clues that may infl uence patient re- of the block diffi cult.
sponses; Selective blockade of stellate ganglion can pro-
3) Repeating the block on more than one occasion vide the pain management specialist with useful in-
using local anesthetics or opioids of varying durations, formation when trying to determine the cause of up-
e.g., lidocaine versus bupivacaine or morphine versus per extremity or facial pain without clear diagnosis. By
fentanyl, and comparing the results for consistency. blocking the brachial plexus(preferably by the axillary
Whether or not this technique stands the test of approach) and stellate ganglion on successive visits, the
time, Winnie’s admonition to clinicians that sympatheti- pain management specialist may be able to diff erenti-
cally mediated pain is often underdiagnosed most cer- ate the nerves subserving the patient’s upper extremity
tainly will. pain. Selective diff erential blockade of the stellate gan-
glion, trigeminal nerve, and sphenopalatine ganglion on
Greater and lesser occipital nerve block successive visits may elucidate the nerves subserving of-

Th e greater occipital nerve arises from fi bers of the dor- ten diffi cult-to-diagnose facial pain.
sal primary ramus of the second cervical nerve and to a
lesser extent from fi bers of the third cervical nerve [4]. Cervical facet block
Th e greater occipital nerve pierces the fascia just below Th e cervical facet joints are formed by the articulations
the superior nuchal ridge along with the occipital ar- of the superior and inferior articular facets of adjacent
tery. It supplies the medial portion of the posterior scalp vertebrae [6]. Except for the atlanto-occipital and atlan-
as far anterior as the vertex. Th e lesser occipital nerve toaxial joints, the remaining cervical facet joints are true
arises from the ventral primary rami of the second and joints in that they are lined with synovium and possess
third cervical nerves. Th e lesser occipital nerve passes a true joint capsule. Th is capsule is richly innervated
superiorly along the posterior border of the sterno- and supports the notion of the facet joint as a pain gen-
cleidomastoid muscle, dividing into cutaneous branches erator. Th e cervical facet joint is susceptible to arthritic
that innervate the lateral portion of the posterior scalp changes and trauma caused by acceleration-deceleration
and the cranial surface of the pinna of the ear. injuries. Such damage to the joint results in pain sec-
Selective blockade of greater and lesser occipi- ondary to synovial joint infl ammation and adhesions.
tal nerves can provide the pain management special- Each facet joint receives innervation from two
ist with useful information when trying to determine spinal levels. Each joint receives fi bers from the dorsal
the cause of cervicogenic headache. By blocking the at- ramus at the same level as the vertebra as well as fi bers
lantoaxial, atlanto-occipital, cervical epidural, cervical from the dorsal ramus of the vertebra above. Th is fact
facet, and greater and lesser occipital nerve blocks on has clinical importance in that it provides an explana-
successive visits, the pain management specialist may tion for the ill-defi ned nature of facet-mediated pain
be able to diff erentiate the nerves subserving the pa- and explains why the branch of the dorsal ramus aris-
tient’s headache. ing above the off ending level must often also be blocked
to provide complete pain relief. At each level, the dorsal
Stellate ganglion block ramus provides a medial branch that wraps around the
Th e stellate ganglion is located on the anterior surface convexity of the articular pillar of its respective verte-
of the longus colli muscle. Th is muscle lies just anterior bra and provides innervation to the facet joint. Selective
to the transverse processes of the seventh cervical and blockade of cervical facet joints can provide the pain
fi rst thoracic vertebrae[5]. Th e stellate ganglion is made management specialist with useful information when
.