Traumatic and Iatrogenic CSF Leaks

Cerebrospinal fluid (CSF) leaks of the lateral skull base and temporal bone can occur from traumatic, iatrogenic, or sporadic causes. Traumatic non-penetrating temporal bone fractures result in CSF leak in 8.5-25% of cases with otic capsule-violating fractures having the highest risk of CSF fistula. Penetrating trauma results in CSF leak 8-12% of the time but has a very high rate of other otologic sequelae such as facial nerve injury and loss of vestibular and hearing function. Lateral skull base surgery has a similar rate of postoperative CSF leak, 3-17%, as penetrating trauma although the rate varies among the approach used with middle cranial fossa approaches having the lowest rate. CSF leak after surgery for chronic ear disease varies widely depending on whether multiple prior surgeries had occurred. While the majority of CSF leaks were controlled with conservative measures including lumbar drainage, the remainder required surgical repair, and delayed recognition of leaks led to increased risk of meningitis.