Abstract

One of the main challenges of endonasal skull base surgery is the precise reconstruction of the dural defect to avoid adverse events.

With the increase in the number of surgeries with endoscopic techniques via endonasal approach, the challenge arose for dural repair and reconstruction of the skull base to avoid the cerebrospinal fistulas that have become frequent, with risks of meningeal infection and/or even death. The vascularized nasoseptal flap has become the gold standard for endoscopic reconstruction of the skull base. Sometimes, the septal mucosa flap may not be available for reconstruction or be insufficient.

The aim of this study is to present our experience with the use of the elongated and pediculated pericranial flap in patients to provide an option for endonasal reconstruction of defects in the skull base and the technique used.

We present our protocol of the indications for using the pericranium flaps and the surgical technique. Herein, we present our surgical experience. In some cases, to elongate the flap, particularly for lesions located more caudally to the clivus, it may be necessary to make other incisions and fold up again, reversing the flap. The final length obtained could be up to 10 to 12 cm or even more, depending on the amount of elongation and if the initial incision starts more posteriorly to the hairline. The advantage of narrowing the width and lengthening the length of the pericranial flap is that the flap passes more easily through the bony opening of the nasal bone to reach the nasal cavity and can cover the entire region of the sphenoid and clivus, better covering the dural defect.

In our knowledge, this is the first description of using an elongated pericranial flap to cover the clivus that has been performed. Eight patients were operated on using the pericranial flap to cover the skull base defect during some endonasal operations to treat different diseases and showed excellent healing of the skull base and we did not have any cases of cerebrospinal fluid (CSF) leakage in the postoperative period.

The pericranial flap provides a great option for endonasal reconstruction of defects in the skull base. There is minimal morbidity at the donor site and it provides a flap of sufficient size to cover the entire anterior and ventral base of the skull.

Keywords: Keywords: endonasal approaches, skull base surgery, pericranial flap, nasoseptal flap, dural reconstruction, cerebrospinal fistulas

8.1 Background

One of the main challenges of endonasal skull base surgery is the precise reconstruction of the dural defect to avoid adverse events. The introduction of endoscopic techniques and endonasal approach to the skull base has led to communication of the intracranial cavity with the paranasal sinuses creating new challenges for the reconstruction of defects caused by the surgery.

The vascularized nasoseptal flap has become the gold standard for endoscopic reconstruction of the skull base. Sometimes, the septal mucosa flap may not be available for reconstruction or may be insufficient. This may be due to previous surgical resection, involvement of the nasal septum due to naso-sinusal cancer, or being smaller than the defect caused by the removal of the lesion.

8.2 Introduction

With the increase in the number of surgeries with endoscopic techniques via endonasal approach, the challenge arose for dural repair and reconstruction of the skull base to avoid the cerebrospinal fistulas that have become frequent, with risks of meningeal infection and/or even death. Initially, we used a graft with adipose tissue and biological glue that resulted in a high incidence of postoperative cerebrospinal fluid (CSF) fistula. In recent years, we have modified our technique for reconstructing the skull base with the nasoseptal flap and the incidence of recurrent CSF fistulas has decreased significantly. However, for certain cases, a major advance in reconstruction has been the double flap, the pedicle pericranium flap, and the septal mucosa flap vascularized by the posterior nasal artery.

8.3 Objective

We present our experience with the use of the elongated and pediculated pericranial flap in patients to provide an option for endonasal reconstruction of defects in the skull base and the technique used.

8.4 Methods

The protocol of the indications for using the pericranium flaps are:

●Reoperations using endonasal access for pituitary and other tumors in which the nasoseptal flap is considered insufficient in size and quality

●Primary indication of the pericranium flap for expanded accesses

●Expanded endonasal access with high CSF flow (opening of cisterns and ventricles)

●Treatment of recurrent postoperative CSF fistulas

●Expansion of endonasal access to intradural clival access

●History of radiotherapy or previous endonasal surgical resection

●Involvement of the nasal septum by tumor