Clinical and Somatosensory Profile of Patients with C1-2 Atlanto-Axial Pain

To comprehensively phenotype patients with acute and chronic pain from the atlanto-axial (C1-2) segment. Patients with acute (<3 months) and chronic (≥3 months) neck pain undergoing C1-2 fusion were enrolled and completed quantitative sensory testing (QST) and self-report measures of pain-related outcomes, opioid use, and psychosocial characteristics prior to surgery. Twenty patients with acute and 21 with chronic pain were enrolled. Median duration of pain (interquartile range) was 2.0 (1.0-5.5) and 365.0 days (213.0-730.0) in the acute and chronic groups, respectively. Median pain intensity (0-10 numerical rating scale) was 7.0 (4.0-9.0) and 4.5 (4.0-6.0). Twenty and 23.8% reported using opioids in the past 6 months. Median Neck Disability Index (short form, 0-24 scale) scores were 17.5 (13.0-20.0) and 12.0 (6.0-19.0). Median PHQ-2 depression (0-6) scores were 1.5 (3.0) and 2.0 (4.0), GAD-2 anxiety (0-6) scores 1.5 (0.0-2.0) and 2.0 (1.0-3.0), and PCS-4 (0-16) catastrophizing scores 9.0 (2.0-10.0) and 6.0 (3.0-12.0). QST revealed pain with brush in 1 patient, pain with light pressure in 4, pain with cold in 5, and prolonged pain after a series of 10 pinprick stimulations (reflecting pain facilitation) in 7. Our cohort was characterized by high levels of pain and disability. About one-fifth reported use of opioids. Depression, anxiety and catastrophizing were on average moderate. Neuropathic pain features as detected by QST were present in a subset of patients who may have had C2 neuropathy in addition to musculoskeletal pain and may therefore benefit from neuropathic pain treatments.