Combined Transpetrosal Approach: 2-Dimensional Operative Video

Abstract

INDICATIONS: CORRIDOR AND LIMITS OF EXPOSURE: 

This approach is suitable for petroclival lesions medial to V cranial nerve that extend in both middle and posterior fossa. It provides multiple surgical corridors with minimal brain retraction.

ANATOMIC ESSENTIALS: NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: 

Several critical neurovascular structures of the petrous bone are at risk during the approach. Meticulous reading of the preoperative images is fundamental. It is mandatory to perform a thin section computed tomography scan, an MRI, and, in case of petroclival meningiomas, a digital subtraction angiography.

ESSENTIAL STEPS OF THE PROCEDURE: 

In the first illustrative case, we present our current “mini-combined petrosectomy” with minimal drilling of the labyrinth. Positioning, skin incision, and craniotomy are illustrated in the video. Once all the important neurovascular structures are identified, we perform the anterior and the posterior petrosectomy, with preservation of the endolymphatic sac. We continue with dura mater opening and tentorium cutting. After tumor removal, we can appreciate an unique view of ipsilateral and contralateral cranial nerves, as well as pituitary stalk and major arteries.

PITFALLS/AVOIDANCE OF COMPLICATIONS: 

To avoid injuries to the main neurovascular structures, neuronavigation, neuromonitoring, and Doppler can be useful.

VARIANTS AND INDICATIONS FOR THEIR USE: 

The second illustrative case shows an extension of the combined petrosectomy to the anterior fossa, this made possible to perform a transsylvian approach for this giant sphenopetroclival meningioma. The patients consented to the procedure and to the publication of his/her images. Appropriate consent was obtained for the publication of the cadaveric images.

Funding

This study did not receive any funding or financial support.

Disclosures

The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.

COMMENTS

The authors present a meticulously detailed explanation of mini-petrosectomy and the combined transpetrosal approach, both highly demanding approaches. Their presentation conveys the procedural steps for both approaches, making them comprehensible. The cadaveric preparation and the quality of the dissection deserve special mention, as they are excellent. The inclusion of a cadaveric study as a prelude to the actual surgical procedure underscores an important model for comprehensive skull base practice. Prior to embarking on a complex procedure that is less familiar to the surgeon, it is imperative to scrutinize all steps and potential pitfalls. Cadaveric practice is an excellent mode for this, which ultimately enhances the quality of patient care provided.^1a

Similarly, we appreciate the thorough description of preoperative assessment, encompassing both the clinical and radiological evaluation. In skull base surgery, this facet carries particular importance, given the sophisticated three-dimensional nature of the approaches and the intricate relationships between neural, bony, and vascular structures.^2a,3a There is no excuse to be surprised by something at surgery that could have been found on more careful examination of the preoperative imaging.

The authors have provided a useful list of potential pitfalls, pinpointing the specific stages of the operative procedure where these challenges may most likely arise. This aspect improves the value of the video and highlights the opportunity the skull base surgical community has to lower complications by providing more multimedia content focused in this area.

The section on closure techniques and plane reconstruction in posterior petrosectomy approaches is helpful as it is an area traditionally regarded as challenging.^4a The authors’ explanation of their technique provides a valuable educational resource, particularly for neophyte skull base surgeons embarking on posterior petrosal procedures.

Overall, this video is one of the most complete available describing this complex approach and we commend the authors for their valuable contribution to the field.

Giovanni Barbagli and Peter Nakaji

Phoenix, Arizona, USA