Cervical Plexus Block pt.2

Cervical Plexus

Anatomy:

It is a plexus of the ventral rami of the first four cervical spinal nerves located in C1 to C4 cervical segment in the neck. It has both cutaneous and muscular branches:

Cutaneous branches:
o Lesser occipital nerve
o Greater auricular nerve
o Transverse cervical nerve
o Supraclavicular nerve

Muscular branches:
o Ansa cervicalis
o Phrenic nerve
o Segmental braches: innervates anterior and middle scalenes

Relations:
• Posteriorly
o Muscles that arise from the posterior tubercle of the transverse process i.e. levator scapulae and scalenus medius
• Anteriorly
o Prevertebral fascia
o Internal jugular vein
o Sternocleidomastoid

Cervical plexus block

Indications are:
Surgical indications:
o Carotid endarterectomy
o Plastic repairs
o Lymph node dissection
o Thyroidectomy
o Tracheostomy
Non surgical indications:
o Neuralgias
o Treatment of hiccoughs
o Pain relief secondary to pharyngeal cancer
o Relief of occipital headaches
Source: Roger D Masters, Elizabeth J Castresana, Manuel R. Castresana. Superficial and deep cervical plexus block: technical consideration. Journal of the American Association of Nurse Anesthetists. June 1995. Vol. 63. No. 3.

Procedure: Superficial Cervical Plexus Block

Patient lies supine with a small towel under the head and the head is turned slightly toward the side which is not being blocked.
• Posterior border of sternocleidomastoid muscle is identified and the midpoint of the muscle is marked.
• 22 gauge, 5 cm short bevel needle is inserted at the midpoint of the posterior border of sternocleidomastoid muscle to approximately half the depth of the muscle
• 3-4 ml of local anesthetic is injected
• An additional subcutaneous injection of local anesthetic is performed cephalad and caudad along the length of the sternocleidomastoid muscle posterior border.

Ultrasound guided superficial plexus block

•It increases the success rate
• Avoids too deep needle insertion and/or inadvertent injections into the important surrounding structures of the neck
• It ensures the spread of local anesthetic in the correct plane
• Transducer is placed on the lateral side of the neck at the midpoint of posterior border os sternocleidomastoid
• Tapering end of the muscle should be visible on screen

Deep cervical plexus block

• Patient is placed supine with head turned on opposite side
• Mastoid process is palpated behind the ear along with transverse process of C6 (Chassaignac’s tubercle) and line is drawn joining both ends
• The transverse process of other cervical vertebra lies on or near this line
• The transverse process of C2 to C4 are palpated and marked
• 22 Gauge, 5 cm short bevel needle is inserted medially and caudally so that needle rests on the transverse process
• Once the transverse process is contacted, needle is withdrawn by 1-2 mm and local anesthetic is injected after frequent aspiration
• After completing the injection, needle is removed and the block is repeated at the next level
• 3-5 ml of local anesthetic is injected at each level.
Single injection technique
• It involves single injection inserted at the level of C4.
• Line is drawn from the cricoid cartilage to the point where external jugular vein crosses the posterior border of sternocleidomastoid which is the level of C6. A line from the thyroid notch is then drawn parallel to the line for C6 to determine C4.
• Using a 22G, 1.5 cm needle, the transverse process of C4 is located by entering perpendicular to the skin and after careful aspiration for blood/CSF, 15-20 mls of local anesthetic solution is injected.

Ultrasound guided deep cervical block

There are many approaches:

1. LA is deposited just behind the carotid sheath at the level of carotid bifurcation. It is simple and safe. Injection into the carotid should be avoided
2. Local anesthetic is deposited into the interscalene groove cranially. The cervical plexus is blocked when LA spills
3. C4 level is marked and the transducer is placed laterally till the transverse process of C4 is identified. The needle is then introduced in the long axis from the posterior end of the probe under direct vision. Once the tip of the needle touches the bony part, it is partially withdrawn and after aspiration, 10-15 ml of local anesthetic is injected, which can be seen spreading along the transverse process

Complications:
• Infection
• Hematoma
• Phrenic nerve blockade
• Local anesthetic toxicity (mostly central nervous system toxicity)
• Nerve injury
• Spinal anesthesia (when large volume of local anesthetic is injected)
• Carotid sheath compression
• Hoarseness secondary to involvement of recurrent laryngeal nerve
• Dysphagia
• Horner’s syndrome