Orthostatic Headache After Suboccipital Craniectomy Without CSF Leak: Two Case Reports

Objective: To review the clinical and radiographic characteristics of orthostatic headache following suboccipital craniectomy without CSF leak after encountering 2 such patients. Background: Orthostatic headache may occur without CSF leak, suggesting alternative mechanisms for postural head pain in some patients. Methods: Patients who were referred for orthostatic headache and suspected CSF leak within 1 year after suboccipital craniectomy but who had negative post-operative head and spine MRI, normal radioisotope cisternography, and normal or elevated CSF opening pressure were identified and their medical records reviewed. Results: Two patients satisfied all inclusion criteria. One underwent suboccipital craniectomy for treatment of Chiari malformation type I in adolescence; the same surgical approach was used to resect a posterior fossa meningioma in the second. Both patients had non-orthostatic headache before surgery and newly developed orthostatic headache later. Delay from surgery to orthostatic headache onset was variable (2–9 months). Headaches were predominantly occipital and pressure-like, worsened by upright posture, bending forward, and exertion. MRI consistently showed adequate decompression of the posterior fossa. Epidural blood patches were unhelpful in the one patient in whom they were performed. Conclusions: Orthostatic headaches may develop after suboccipital craniectomy in the absence of CSF leak. Possible mechanisms include (1) scarring of the dura in the posterior fossa that leads to compensatory increased distensibility of lumbar dura and (2) sensitization of mechanosensitive dural nociceptors from altered skull-dura apposition.