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Page 8 of 11 Azab et al. Mini-invasive Surg 2020;4:88 I http://dx.doi.org/10.20517/2574-1225.2020.75

Figure 6. Pre- (A-E) and postoperative (F-H) magnetic resonance images in a case of tuberculum sellae meningioma excised via an
endoscope-controlled keyhole supraorbital approach. Extension beyond the internal carotid on the left and anterior cerebral artery
encasement on the right led to selection of endoscope-assisted keyhole transcranial approach instead of an extended endoscopic
endonasal transsphenoidal approach

endonasal over supraorbital keyhole approach include early devascularization of the tumor, less
manipulation of the optic nerves, chiasm and brain, better visualization of the medial optic canal allowing
removal of intracanalicular tumor extensions, removal of all involved bone at the skull base and access to
potentially invaded intranasal structures such as the ethmoid cells [10,34,51] . The advantages of the supraorbital
keyhole over the endoscopic endonasal approach, on the other hand, include avoidance of an infected field,
avoidance of trauma to the nasal passages and olfactory mucosa, and a wider view of the lateral extent of
the tumor, making it more suitable for tumors with extension lateral to the carotid artery or optic nerve and
for tumors with vascular encasement [10,34] . Although CSF leaks are less frequent following the supraorbital
keyhole approach, the incidence of CSF leakage that initially complicated expanded endonasal skull base
approaches has been reduced dramatically with the advent of the nasoseptal flap [6,52] .

Across the literature, a limited number of studies exist that directly compare the endoscopic endonasal
versus supraorbital keyhole approach for resection of anterior cranial base meningiomas. In these studies,
scores and algorithms have been suggested to help select the suitable approach [3,6,27,42,50,53] [Figure 6]. As
a matter of fact, one of the important factors that lessen the credibility and practical applicability of the
results of such studies, however, is that the indications for each approach may differ, and it is impossible to
[10]
compare two approaches for removal of the very same tumor .
Although a detailed account of the published results is beyond the scope of this review, it is important
to note that for olfactory groove meningiomas, the endoscope-assisted supraorbital eyebrow approach
leads to a higher extent of resection and lower rate of complications than the purely endoscopic endonasal
[7]
approach . while for tuberculum sellae and planum sphenoidale meningiomas, the two approaches yield
[34]
more or less similar rates of gross total resection, near total resection and visual recovery . It should
be borne in mind that not all anterior skull base meningiomas are amenable to minimally invasive
[27]
approaches .
[54]
In a recently published meta-analysis, Khan et al. compared the endoscope-assisted supraorbital keyhole
approach with the microscopic transcranial and expanded endoscopic endonasal approaches for surgical
resection of olfactory groove and tuberculum sellae meningiomas. In the authors conclusions, case
selection was paramount in establishing the role of endoscope-assisted keyhole surgery in these tumors.