An “internal” CSF fistula. Incidence following suboccipital craniectomy: 26-28% 1).
May be asymptomatic, but also may be associated with H/A, nausea/vomiting, local pain/tenderness. Some are soft and compressible, others may be tense. Indications for operation:
1. external leak (CSF fistula)
2. threatening integrity of incision
3. cosmetic deformity
4. causing symptoms