Cranial Settling Causing Intracranial Hemorrhage Through Violation of the Skull Base by Cervical Spine Instrumentation

Background: Rheumatoid arthritis (RA) is a chronic inflammatory polyarthropathy that affects many synovial joints favoring the hands, knees, and vertebral articulations. Joint laxity manifests as sub-axial instability, atlantoaxial instability (AAI), and cranial settling (CS).

Case description: 70-year-old female with past medical history of RA, Hashimoto's thyroiditis, osteoporosis, history of C1-2 fusion for instability 15 years prior, with subsequent revision cervico-thoracic fusion for degeneration and trauma two years prior, presents with new onset headache, nausea and vomiting of 36-hour duration. Neurologic exam was only notable for mild right dysmetria. Workup revealed acute hemorrhage in the posterior fossa with migration of the right rod implant and screw tulip, as a result of cranial settling. The patient underwent occipital-cervical fusion with removal of the migratory hardware.

Conclusions: Intracranial rod migration and hemorrhage secondary to cranial settling is a rare complication that must be brought to the attention of surgeons operating on patients with RA.

Keywords: Cranial Settling; Intracranial Hemorrhage; Rheumatoid arthritis.