What is a Cervical Sympathetic Block?
A cervical sympathetic block is an interventional pain management technique that targets the sympathetic nerves located in the cervical region. It is primarily used to diagnose or treat conditions resulting from overactivity or dysfunction of the sympathetic nervous system, such as complex regional pain syndrome (CRPS), refractory angina, or certain vascular and neuropathic pain disorders of the head, neck, and upper extremities.
Anatomy of Cervical Sympathetic Nervous System
The sympathetic chain in the cervical region runs anterior to the longus colli muscle and is divided into three main ganglia:
- Superior cervical ganglion (located at C2-C3 level)
- Middle cervical ganglion (variable position, often at C6)
- Stellate ganglion (fusion of inferior cervical and first thoracic ganglia, usually at C7-T1)
- A cervical sympathetic block often refers specifically to a stellate ganglion block, due to its accessibility and effectiveness in modulating sympathetic tone in the head, neck, and upper limb.
Indications for a Cervical Sympathetic Block
A cervical sympathetic block is indicated in conditions that include:
- Complex Regional Pain Syndrome (CRPS) of the upper limb
- Herpes zoster and postherpetic neuralgia affecting the face or arm
- Refractory angina pectoris
- Hyperhidrosis of the upper extremities
- Vascular insufficiency such as Raynaud’s phenomenon or Buerger’s disease
- Phantom limb pain or other sympathetically maintained pain syndromes
Procedure of Cervical Sympathetic Block
The block is typically performed under fluoroscopic or ultrasound guidance to ensure precision and minimize complications. The individual is placed in a supine position with slight neck extension. A local anesthetic agent, such as lidocaine or bupivacaine, is injected near the sympathetic chain—commonly at the level of C6 or C7. In some cases, adjunct medications like corticosteroids may be added to prolong the effect.
Expected Response after Cervical Sympathetic Block
A successful block is often confirmed by signs such as:
- Horner’s syndrome (ptosis, miosis, anhidrosis on the ipsilateral side)
- Increased skin temperature in the affected limb
- Reduction in pain or other sympathetic symptoms
Risks and Complications of Cervical Sympathetic Block
Although generally considered safe, cervical sympathetic blocks carry certain risks, including:
- Intravascular injection (vertebral or carotid artery)
- Seizures (due to local anesthetic toxicity)
- Dysphagia or hoarseness (due to recurrent laryngeal nerve involvement)
- Pneumothorax (rare)
- Infection, hematoma, or nerve injury
Contraindications of Cervical Sympathetic Block
Cervical sympathetic blocks are not advised in cases of:
- Coagulopathy or anticoagulant use
- Local infection at the injection site
- Allergy to local anesthetics
- Unstable medical conditions
Clinical Importance of Cervical Sympathetic Blocks
Cervical sympathetic blocks are both a diagnostic and therapeutic tool. A positive response can help confirm sympathetically maintained pain as a component of an individual’s condition and may be followed by repeated blocks or more permanent solutions like radiofrequency ablation in chronic cases.