Superior Cervical Ganglion Block, Transcranial Doppler
Condition: Brain Aneurysm; Aneurysm, Ruptured
MeSH terms: Intracranial Aneurysm; Aneurysm; Aneurysm, Ruptured
Study type: Interventional

Summary: 
      The aim of this study is to assess blood flow velocity in middle cerebral artery measured by
      transcranial doppler to determine the efficacy of SCG block in decreasing incidence or
      severity of vasospasm after MCA aneurysm surgery.
    

Detailed description: 
      Sympathetic innervation to the face and head is by superior cervical ganglion(SCG), which is
      the most cranial part of the sympathetic chain. It is suited in a plication of the
      prevertebral fascia anterior to the longuscapitis muscle and dorsal to the internal carotid
      artery, posteromedial to the vagus nerve at c3 level. It's mainly located at the level of the
      transverse processes of the second and third cervical vertebrae. However, it may reach
      caudally to the upper border of the fourth cervical vertebra.

      Noradrenergic sympathetic nerve fibers mainly originating in the superior cervical ganglion,
      accompanying the carotid artery supply cerebral vasculature particularly the pial vessels.

      Superior cervical ganglion block was previously tried in managing neuropathic pain,
      neuropathic pain in head and face region was investigated in patients using ganglionic local
      opioid analgesia (GLOA) at the superior cervical ganglion (SCG) ,The short-term analgesic
      effect of the first blockade by GLOA was significant with a mean pain reduction of 52% (p <
      0.001).

      Superior cervical ganglion block also used as an alternative treatment to tinnitus not
      responding to conventional therapy, it increases cholear blood flow and this can explain the
      efficacy of block.

      Superior cervical ganglion block was used to improve cerebral perfusion in patients with
      cerebral vasospasm after aSAH.

      Aneurysmal subarachnoid hemorrhage (aSAH) may develop vasospasm in 70% of patients.
      Morphological changes occur in the cerebral vessels after SAH, and the inflammatory response
      and local chemical agents are responsible for the induction of vasospasm.

      Vasospasm is rare in the first 3 days after SAH, it reaches peak incidence at 7 to10 days and
      usually resolves by 10 to14 days after SAH.

      The sympathetic system also has a role in the pathogenesis of this process, cervical
      sympathetic stimulation leads to constriction in intracerebral vessels and dilation occurs
      when these fibers are interrupted. Efflux and reuptake of the neurotransmitter may be
      prevented by sympathectomy.

      Common treatments to reduce vasospasm include ;triple H therapy (hypertension ,hypervolemia
      and hemodilution), intraarterial infusion of Smooth muscle relaxants (papaverine, Verapamil)
      and endovascular balloon angioplasty . Also (nimodipine) calcium channel blocker
      administration is used as a prophylactic measures.

      Transcranial doppler (TCD) is a non-invasive technique which can be used to observe velocity,
      direction and properties of blood flow in the cerebral arteries by means of a pulsed
      ultrasonic beam, based on the Doppler effect of ultrasounds concerning frequency variations
      in sound waves as a result of relative motion between source and signal receiver. It was
      previously used in traumatic brain injury(TBI),stroke, anesthesia and intensive care.
    

Intervention name(s): Superior Cervical Ganglion Block
Intervention type(s): Procedure
Intervention description(s): Under X-ray guidance, a 23-gauge radiofrequency top-pole needle with an active tip of 5 mm is inserted for test blockade. The needle is directed at the facet joint of the 3rd and 4th cervical vertebrae.The needle is introduced parallel to the radiographic projection and is projected as a dot approximately 1 cm anterior to the spine. The radiographic projection is then changed to lateral, and the needle is slowly advanced until the tip was situated at the anterior border of the third cervical vertebra. On the anteroposterior projection, the tip of the needle is projected over the lateral part of the facetal column. When the tip of the needle is in position, 0.3 mL of Omnipaque is injected. On the transverse projection, the contrast is distinctly anterior to anterior border of the vertebral bodies, and in the anteroposterior projection, the contrast is seen spreading in a space overlying the facetal column in a cranial as well as caudal direction.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Supportive Care
Keywords: middle cerebral artery