Grisel syndrome in adult patients. Report of two cases and review of the literature.

CASE REPORT Case 1 A 50-year-old female intravenous drug user presented with neck pain and electrical sensations in the upper and lower limbs on neck flexion (Lhermitte’s sign). There was no history of head and neck trauma but she reported tonsilopharyngitis one to two weeks prior to consultation. Her physical examination was normal except for a positive Lhermitte’s sign. Magnetic resonance imaging (MRI) of the cervical spine revealed a mass infiltrating the posterior subligamentous region of the anterior arch of C1, the odontoid and the body of C2 and compressing the bulbo-medullary junction (Figure 1). and an increase of the atlanto-dental interval (Figure 2). The CT-scan did not show any bony destruction or a rotatory subluxation (Figure 3). The patient received antibiotics with wide spectrum coverage and was stabilized in a Halo vest after closed reduction. The radiological follow-up revealed a decrease in the prevertebral collection as well as a decrease in the spinal cord compression (Figure 4 and 5). After three months the patient fell and presented to the emergency room with loosening of the Halo. She was neurologically intact but the flexion cervical x-ray revealed a C1C2 instability (Figure 6). The patient underwent a C1/C2 fusion, with C1 lateral mass screw and a pars screw (Figure 7). At her last follow-up (five months), the patient was doing very well and was pain-free.