How I do it: extradural clinoidectomy

Closure of small skull base defects with muscle plug napkin ring technique: how I do it

BACKGROUND

Defects through the skull base into the paranasal sinuses can occur during anterior skull base procedures, risking cerebrospinal fluid leak and infection if not repaired.

METHODS

We describe a muscle plug napkin ring technique for closure of small skull base defects, wherein a free muscle graft slightly bigger than the defect is packed tightly in the defect, half extracranially and half intracranially and sealed with fibrin glue. The technique is illustrated in the case of a 58-year-old woman with a large left medial sphenoid wing/clinoidal meningioma.

CONCLUSIONS

The muscle plug napkin ring technique is a simple solution to small skull base defects.

Tailored Anterior Clinoidectomy: Beyond the Intradural and Extradural Concepts

Anterior clinoidectomy (AC) is a key microsurgical step for the safe and successful management of parasellar pathologies that involve the anterior clinoid process (ACP) and the optic canal. Traditionally, extra and intradural ACs are performed separately according to the surgeon's experience or preference. The objective is to present and discuss the tailored AC concept through illustrative cases. We conducted a retrospective record review of three patients who underwent AC as a surgical step for the treatment of parasellar pathologies that involve the ACP and optic canal. A review of the relevant literature on AC was performed in the PubMed, LILACS, and SciELO databases.

In all three cases, the pterional craniotomy was the preferred approach for AC. Case 1, a 47-year-old female patient with type III anterior clinoidal meningioma, underwent a tailored intradural technique (optic canal unroofing) with total tumor resection and complete visual recovery. Case 2, a 63-year-old female patient with a complex type II anterior clinoidal meningioma with extensive hyperostosis of the ACP, underwent a hybrid AC technique with complete removal of the tumor and visual improvement. Case 3, a 62-year-old female, underwent a tailored intradural AC for clipping an incidental carotid-ophthalmic aneurysm.

Tailored AC aims to provide adequate exposure with less risk of neurovascular injury, allowing enough space to safely treat parasellar lesions. The type, size, and location of the lesion, as well as the surgeon’s experience, should always be considered for surgical planning.

Mini-Pterional Craniotomy and Extradural Clinoidectomy for Clinoid Meningioma: Optimization of Exposure Using Augmented Reality Template: 2-Dimensional Operative Video

A "keyhole" approach to a deep-lying skull base lesion, as such a clinoid meningioma, can be a daunting challenge.1-3 The minimally invasive exposure must be precisely placed and adequately wide to accomplish the surgical goal. Surgical rehearsal in virtual reality (VR) can not only increase the confidence of the surgeon through practice on patient-specific anatomy,4 but it can also generate navigation-integrated templates to ensure precise placement and adequate bone openings. In this operative video, we demonstrate the use of an augmented reality (AR) template in a 69-yr-old woman with a growing clinoid meningioma. The 3-dimensional, VR rendering (SNAP VR360, Surgical Theater Inc, Cleveland, Ohio) of her right clinoid meningioma was used in surgical rehearsal for the mini-pterional approach with extradural clinoidectomy. The optimal opening was saved as a VR file and, at surgery, projected into the eye-piece of the navigation-tracked microscope (Synchronized AR v3.8.0, Surgical Theater Inc). In this manner, the surgical opening in the template was visible in AR on the patient's anatomy in real time during surgery. The template enhanced the planning of the incision and soft-tissue exposure, guided the drilling of the sphenoid wing, facilitated the extradural clinoidectomy,5 and ultimately facilitated the accomplishment of the surgical goal of total resection of the meningioma. With this application of novel technology, the surgeon is no longer using navigation to get her/his bearings. Instead, the surgeon is using AR-enhanced navigation to duplicate a plan that is known to work. This is a fundamental paradigm shift.  Patient consent was obtained prior to the creation of the video and is available on request.