Radio-anatomical analysis of the pericranial flap “money box approach” for ventral skull base reconstruction

Objectives/Hypothesis

To evaluate the versatility of the pericranial flap (PCF) to reconstruct the ventral skull base, using the frontal sinus as a gate for its passage into the sinonasal corridor "money box approach."

Study Design

Anatomic-radiological study and case series.

Methods

Various approaches and their respective defects (cribriform, transtuberculum, clival, and craniovertebral junction) were completed in 10 injected specimens. The PCF was introduced into the nose through the uppermost portion of the frontal sinus (money box approach). Computed tomography (CT) scans (n = 50) were used to measure the dimensions of the PCF and the skull base defects. The vertical projection of the external ear canal was used as the reference point to standardize the incisions for the PCF.

Results

The surface area and maximum length of the PCF were 121.5 ± 19.4 cm² and 18.3 ± 1.3 cm, respectively. Using CT scans, we determined that to reconstruct defects secondary to transcribriform, transtuberculum, clival, and craniovertebral approaches, the PCF distal incision must be placed respectively at −3.7 ± 2.0 cm (angle −17.4 ± 8.5°), −0.2 ± 2.0 cm (angle −1.0 ± 9.3°), +5.5 ± 2.3 cm (angle +24.4 ± 9.7°), +8.4 ± 2.4 cm (angle +36.6 ± 11.5°), as related to the reference point. Skull base defects in our clinical cohort (n = 6) were completely reconstructed uneventfully with the PCF.

Conclusions

The PCF renders enough surface area to reconstruct all possible defects in the ventral and median skull base. Using the uppermost frontal sinus as a gateway into the nose (money box approach) is feasible and simple.

Level of Evidence

NA Laryngoscope, 2017

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