Multiregional Spontaneous Skull Base Defects: A Single Institution Experience
University of Florida
Title: Multiregional Spontaneous Skull Base Defects: A Single Institution Experience
Aim: Evaluate the prevalence of multiregional skull base defects in patients presenting with spontaneous encephaloceles.
Background: Spontaneous encephaloceles (SEs) can occur in the anterior and lateral skull base, where cortical bone is often less than 1mm or dehiscent. Progressive thinning of this bone has been linked to idiopathic intracranial hypertension (IIH). Global intracranial processes may affect multiple regions of the skull base. To date, there have been limited reports regarding the frequency of multiregional bony defects of the anterior and lateral skull base in patients with SEs.
Materials and methods: After IRB approval, a retrospective chart review was performed for adults with a diagnosis of encephalocele treated at our tertiary care center. SEs were limited to patients without a history of intracranial tumors, head trauma, chronic ear disease, prior ear / sinus surgery or iatrogenic injury. The skull base was divided into 3 regions: anterior (A), right lateral (B), and left lateral (C). Skull base images were reviewed for defects by a neurotologist and rhinologist.
Results: Seventy SE patients were identified with an average follow up of 30 (range 1-145) months. They were mostly female (87%), with a mean age of 55 13 years and a mean body mass index (BMI) of 37.1 7.9 kg/m2. Known obstructive sleep apnea and IIH were present in 7 (10%) and 15(21%) of patients, respectively. The average cerebrospinal fluid (CSF) opening pressure was 34 7 cm H2O in IIH patients whose diagnosis was confirmed by lumbar puncture (n = 5). History of meningitis and seizure were noted in 7(10%) and 11(16%) of patients, respectively. 27 patients (38%) had multiregional skull base defects. Seventeen patients had bony defects in two skull base regions (A+B, A+C, or B+C), 10 had bony defects in 3 skull base regions (A+B+C). The average BMI in patients with multiregional defect was 38.4 kg/m2 compared to 36.4 kg/m2 in those without, however this was not statistically significant (p = 0.40). 61 patients presented with spontaneous CSF leak, and 4 had leaks involving both the anterior and lateral skull base. 58 patients underwent operative repair, 4 required revision of the primary surgery, and 2 required repair of a second site.
Conclusions: Multiregional skull base defects are common among patients presenting with SEs; however, few require repair of either of more than one defect. Skull base surgeons should counsel patients on the presence of multiregional skull base defects and the potential need for additional repair. Long-term follow up studies are needed to better understand the natural history of multiregional skull base defects.
Evaluate the prevalence of multiregional spontaneous bony defects in patients presenting with spontaneous encephalocele
Determine the risk of developing CSF leak or encephalocele from other defects after repair of one skull base defect
Investigating the rate of multiregional CSF leak in our patient population