Intermediate Cervical Plexus Block (ICPB) In Refractory Chronic Daily Headache After Whiplash: Prospective Audit In 43 Patients

Background: Chronic daily headache can develop or pre-existing episodic headache can worsen after whiplash and is termed persistent headache attributed to whiplash. It can be a therapeutic challenge and often results in severe disability. The objective was to assess the management of patients with refractory secondary chronic daily headache referred to a pain physician in consideration for greater occipital nerve block. Methods: Prospective service evaluation in adult patients with oro-facial pain and headaches. Patients underwent specialist neurology review and analgesic overuse headache was excluded. Patients with chronic daily headache with a past history of neck trauma were included. Cervical facet joint dysfunction and intracranial pathology were excluded. An initial cohort of 27 patients received occipital nerve block without benefit. Subsequently, all patients were offered ultrasound guided intermediate cervical plexus block with local anesthetic and steroid mixture. Four-week headache diary, Brief Pain Inventory-Short Form and Hospital Anxiety Depression Scale questionnaires were completed at baseline and three months post-intervention. Results: Over a 41-month period, 43 patients were reviewed. The first 27 patients (27/43, 63%) reported no benefit with occipital nerve block. Subsequently, patients were offered intermediate cervical plexus block(s). Four patients refused. Thirty-nine patients received the intervention. Thirty-two patients (32/39, 82%) reported significant reduction in headache frequency and intensity at three months. Failure rate was 18% (7/39). Conclusion: The cervical plexus could play a significant role in the development or worsening of pre-existing headache after whiplash. Intermediate cervical plexus block may have a role in the management of refractory chronic daily headache following whiplash injury.