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Page 10 of 18 Avery et al. Mini-invasive Surg 2021;5:17 https://dx.doi.org/10.20517/2574-1225.2021.05

operative emesis. Similarly, total intravenous anesthesia with propofol is used with a smooth emergence
from anesthesia to avoid post-operative emesis and “bucking” on the endotracheal tube during
[32]
[31]
extubation . In our experience, lumbar drainage is not necessary to ensure effective reconstruction .
Should a nasoseptal flap not be available, other vascularized flaps may be considered such as a pedicled
middle or inferior turbinate flap or pericranial flap tunneled through a nasionectomy [33,34] . In cases with no
available vascularized options, multilayered avascular reconstructions with autologous fat, fascia lata and
synthetic materials reinforced with Merocel (Medtronic, Dublin, Ireland) sponges may be required,
[35]
although CSF leak rates tend to be higher compared to vascularized reconstruction techniques .
An important aspect of skull base reconstruction to be stressed is to utilize a protocol based on the degree of
intra-operative CSF leak. Planning the reconstruction, including back-up options, prior to surgery and
adjusting as necessary based on intra-operative findings will help ensure a low post-operative CSF leak rate
of less than 5% and hopefully much lower, even for high-grade leaks encountered in anterior cranial fossa
surgery .
[31]
Outcomes
Recent series have indicated overall excellent visual outcomes for tuberculum sellae meningiomas
approached by the endonasal route [Table 1] [13,24,26,36-43] . Yang et al. performed a meta-analysis of studies
[19]
assessing the endonasal endoscopic route vs. transcranial approaches for tuberculum sellae meningiomas
and found higher rates of visual improvement (85.7% vs. 55.1%) in the endoscopic cohort with similar rates
of gross total resection (74.5% vs. 76.1%). CSF leak rates were significantly higher in the endoscopic cohorts
(8.6% vs. 2.1%), although we have recently published a CSF leak grading scale and recommended skull base
reconstruction protocol that has resulted in a CSF leak rate of only 2% (1 of 49 patients) of patients with
[31]
high flow (Grade 3) CSF leaks . A recent meta-analysis has demonstrated a significant decrease in CSF leak
rate over time to 4% with the endoscopic endonasal approach, reported in the last 5 years .
[44]
In 2020, Youngerman et al. published a resectability scoring system to predict gross total resection for
[45]
planum sphenoidale and tuberculum sellae meningiomas using the endoscopic endonasal route. One point
is assigned to each of the following: (1) prior surgery; (2) complete ICA encasement on more than 1 MRI
plane; and (3) lateral extension of the tumor beyond the lateral margin of either optic nerve. Using their
case series of 51 operations, they found that scores of 0, 1 and 2 were associated with gross total resection
rates of 97%, 54% and 12.5%, respectively. They found that tumor size, medial optic canal involvement,
brain edema and encasement of the anterior cerebral arteries were not predictive of gross total resection.

Complications
While endoscopic endonasal surgery places the tuberculum sellae/planum sphenoidale meningioma in
direct line of site, the surrounding critical structures may be at risk of iatrogenic injury as the tumor may be
quite adherent to these structures or encase them. Thorough pre-operative planning, in addition to the
diligent use of neuronavigation and micro-Doppler probe, is highly recommended to minimize risks of
complications. Injury to the ICA and ACA should be immediately investigated to find the bleeding site with
an attempt to repair with clip ligation, tamponade with muscle tissue or synthetic material, or sacrifice of
the parent vessel as deemed necessary. Once the bleeding has been stabilized, the procedure should be
aborted, and the patient is brought to the angiography suite for evaluation and treatment of arterial injury
and/or pseudoaneurysm formation. At our institution, we have implemented a “carotid injury timeout” in
conjunction with a standard operative timeout for high-risk procedures. Additional equipment is made
available in the room to deal with a major arterial injury, including essential instruments, backup
equipment, medications and crossmatched blood. The neuro-interventional team is notified prior to the