A Comparative Analysis of Surgical Repair of Anterior and Lateral Cranial Base Meningoencephaloceles

Object: In adults, spontaneous cerebrospinal fluid (CSF) leaks most commonly arise from meningoencephaloceles of the anterior and lateral cranial base. Idiopathic intracranial hypertension (IIH) may play an important role in the in the development of spontaneous CSF leaks and recurrence after surgical repair. There is a paucity of literature on the optimal strategy for diagnosis and treatment of IIH in anterior and lateral cranial base meningoencephaloceles. The purpose of this study is to compare patient demographics, radiologic findings, and surgical outcomes between anterior and lateral cranial base meningoencephaloceles and to present a treatment algorithm for the diagnosis and management of IIH in these patient populations.

Methods: Data were collected for 86 patients undergoing 87 operations for repair of spontaneous CSF leaks (44 lateral and 43 anterior cranial base leaks) at our institution between 2004–2016. Iatrogenic, traumatic, and CSF leaks secondary to neoplastic or inflammatory processes were excluded. Anterior cranial base defects were repaired using an endoscopic endonasal approach and lateral cranial base defects were repaired by a combined middle fossa craniotomy and mastoidectomy. Patient demographics, presenting symptoms, previous history, preoperative imaging, Beta-2 transferrin testing, intraoperative data, and outcomes were compared between anterior and lateral patient cohorts. The decision for shunting was made according to an algorithm in which patients with opening pressure on lumbar puncture ≥ 25 cm H2O or 20–24 cm H2O with other high-risk features were recommended for shunting.

Results: The mean age was 55.9 years and mean BMI was 35.0; these were similar between cohorts. There was a significantly higher proportion of females in the anterior cohort (84.0 vs 63.0%, p = 0.028). History of chronic local infection was significantly more common in the lateral group (88.6% vs 25.6%, p < 0.001). Bilateral cranial base defects were also significantly more common in the lateral cohort (27.3% vs 7.0%, p = 0.012). A history of meningitis was slightly more common in the anterior cohort, although this did not reach significance (20.9% vs 13.6%, p = 0.368). The presence of an empty sella was significantly more frequent in the anterior cohort (34.9 vs 15.9%, p = 0.042). Utilizing our algorithm, significantly more patients in the anterior cohort received a shunt (51.2 vs 22.7%, p = 0.006). Medical, repair-related, and shunt-related complications occurred in 5.7, 6.9, and 18.8% respectively. Overall, three (3.4%) patients had a recurrent CSF leak, all in the anterior cohort.

Conclusion: In this study, we found that female gender, presence of empty sella, and need for shunting were significantly more common in the anterior cohort. Conversely, a history of chronic local infection and bilateral defects were significantly more common in the lateral cohort. This might suggest that IIH plays a larger role in the development of anterior cranial base defects, whereas chronic infection and congenital anatomic susceptibility may play larger roles in the development of lateral cranial base defects. Finally, utilizing our algorithm, CSF leak recurrence only occurred in 3.4%.