What different nerve blocks can be used for diagnosis and treatment of CRPS?

What different nerve blocks can be used for diagnosis and treatment of CRPS?

The two most common sympathetic nerve blocks utilized for both diagnosis and treatment of CRPS are stellate ganglion and lumbar sympathetic blocks. The stellate gan-glion is a sympathetic ganglion made up of the fusion of the inferior cervical and first thoracic sympathetic ganglia. Anatomically, it is located near the transverse processes of C₇ or T₁ and has axons that arise from sympathetic cell bodies from the T₁–T₅ spinal cord levels. Axons that pass through the stellate ganglion supply sympathetic innerva-tion to the head, neck, and upper extremities. Stellate ganglion blocks can also be used to treat upper extremity peripheral vascular disease.

Traditionally, a stellate ganglion block is performed at the level of the transverse process of C₆, at Chaissagnac’s tubercle. Some practitioners perform the procedure under fluoroscopic guidance at the C₇ level. A good indication of a successful sympathetic block to the head and neck region is Horner’s sign (ptosis, miosis, and anhydrosis). A good indicator of a successful sympathetic block to the upper extremity is either vasodilatation or increased temperature in the arm.

Complications of a stellate ganglion block include hoarseness, intravascular (vertebral artery) injection caus-ing seizures, pneumothorax, bradycardia, diaphragmatic paralysis, intrathecal/epidural injection, arm weakness, bleeding, and infection.

Lumbar sympathetic blocks are indicated for CRPS involving the lower extremities, as well as for peripheral vascular disease. These blocks should be done under fluo-roscopic guidance with contrast dye confirmation of proper needle placement. The needle is placed anterolateral to the body of the lumbar vertebra at the L₂, L₃, and/or L₄ levels.

Complications that can occur include inguinal neuralgia, a selective nerve root block, intravascular injection, spinal/ epidural anesthesia, renal trauma, and intradiscal injection.