The occipital nerve blockade is used both diagnostically and therapeutically in the treatment of occipital neuralgia.
After informed consent is obtained, the patient is placed in the sitting position with the head flexed forward. The occipital nerve is located at the midpoint between the mastoid process and the greater occipital protuberance at the superior nuchal line. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1-in. (2.5-cm), 21- to 25-gauge needle is inserted perpendicular to the superior nuchal line. Before reaching the periosteum of the skull, paresthesias in the occipital nerve distribution may be elicited. If not, the periosteum is contacted and the needle withdrawn slightly. After negative aspiration, 3 to 5 mL of local anesthetic is injected to block the occipital nerve (Fig. 67-3).
FIGURE 67-3. Occipital nerve block. Approach for occipital nerve block and neural blockade.
Localization of the nerve may be accomplished by palpation of the occipital artery just lateral to the nuchal ridge. The nerve runs with the occipital artery, innervating the posterior portion of the skull. A nerve stimulator may be used for precise needle placement. An alternate approach may be used with the patient positioned as above with anatomic landmarks identified. A 2-in. (5-cm), 21- to 25-gauge needle is inserted subcutaneously along the middle third of the superior nuchal line.
After negative aspiration, 5 mL of local anesthetic is injected to block the greater and lesser occipital nerves (see Fig. 67-3).
Intravascular injection can occur, resulting in systemic toxicity and seizures, especially if larger volumes are used. Bleeding due to vascular injury also may occur. Nerve injury secondary to injection into the nerve may result in persistent numbness over the posterior portion of the scalp.