Introduction: The mainstay of treatment of anterior skull base meningiomas, including Tuberculum
Sellae Meningiomas (TSM) and Olfactory Groove Meningiomas (OGM), is surgery. This
can be challenging given the surrounding vital structures. Traditionally, these meningiomas
are resected using a microscopic transcranial approach (TC). In the past decade, however,
the endoscopic endonasal transsphenoidal approach (eTSS) has offered an alternative
corridor for both TSM and OGM. However, it remains to be elucidated which approach
offers the best surgical outcomes. The TC and eTSS approaches are compared and contrasted.
Methods: A systematic Embase and PubMed search was conducted to identify relevant articles
on surgical outcomes of TSM and OGM from January 2005 until December 2015. Articles
were excluded based on predetermined exclusion criteria, which included: articles
not in English, case reports, reviews, cadaveric studies, studies with endoscopic
assistance in the endonasal group, giant (>6cm) OGMs and congress abstracts. Comprehensive
Meta-analysis (CMA) software was used to calculate fixed overall prevalence with 95%-confidence
interval (CI) for TSM and OGM for gross total resection (GTR), visual improvement,
post-operative cerebral spine fluid (CSF) leakage, mortality and internal carotid
artery (ICA) injury in eTSS and TC respectively.
Results: The search resulted in 773 case series that were screened for title and abstract,
resulting in 172 articles that were screened full text. Of these, 43 articles were
included in the meta-analysis. For TSM resections, pooled fixed prevalence and subgroup
analysis by surgical approach revealed that eTSS was associated with a higher mortality
(6.50%; 95%-CI: 3.00–13.9%; I2=0%) than TC (2.40%; 95%-CI: 1.5–4.0%, I2=0%) (P-interaction
comparing the two groups = 0.04). However, eTSS was not significantly different from
TC with respect to GTR (P-interaction = 0.09), visual outcome (P-interaction = 0.24),
CSF leak (P-interaction = 0.09) or increased rate of ICA injury (P-interaction = 0.12).
For OGM resections, eTSS as compared with TC was associated with decreased GTR (68.2%;
95%CI: 56.4–78.1%; I2=0% for eTSS versus 88.8%; 95%-CI: 85.7–91.3%, I2= 50.7% for
TC) (P-interaction comparing the two groups: <0.01), poorer visual outcome (28.5%;
95%CI: 18.4–41.4%; I2=54.3% for eTSS versus 74.2%; 95%-CI: 64.3–82.2%; I2=58.4% for
TC)(P-interaction comparing the two groups = 0.02) and greater CSF leak incidence
(29.7%; 95%-CI: 20.6–40.8%; I2=0% for eTSS versus 10.7%; 95%-CI: 8.2–13.8%; I2=66.0%
for TC)(P-interaction comparing the two groups = 0.005). However, eTSS was not associated
with ICA injury (P-interaction = 0.14) or increased mortality (P-interaction = 0.99)
when compared with TC. Further subgroup analyses by age, gender and continent where
the study was performed showed no significant differences between these groups (all
P-interaction>0.05).
Conclusion: The eTSS approach for TSM was associated with higher mortality when compared with
TC, but not morbidity. For OGM, TC resulted in greater GTR rate, visual improvement
and fewer CSF leaks. Based on this study, we conclude that even though the eTSS approach
could be an alternative for selective patients, the microscopic transcranial approach
is still a useful and valid technique for the resection of anterior skull base meningiomas.
However, as technology and expertise expand, eTSS outcomes could continue to improve
for these meningiomas.
