Endoscopy in endonasal skull base surgery

I am the Chief of the Neurosurgical Department of the Federico II University Hospital in Naples, Italy. It is a tertiary referral hospital, affiliated to the Federico University of Naples. We have two operating rooms dedicated to neurosurgery; one of these is an advanced, fully endoscopic integrated operating room.

Endonasal endoscopic surgery was first introduced by myself at the end of 1996, being the first implementation in Europe and second only to Jho and Carrau in Pittsburgh, US. At that time we had little experience in endonasal endoscopy and we started gradually with the first operations, which lasted several hours, due to the lack of confidence with the endoscope, endoscopic anatomy, endoscopic skill and dedicated endoscopic instruments. We very quickly gained experience and started a didactic activity, teaching others how to perform these types of operations, organising annual hands-on courses and offering fellowship programmes to surgeons who want to specialise in endoscopic endonasal skull base surgery.

The advantages of introducing the technique to the hospital are manyfold; there is less patient discomfort and fewer complications post-operatively, which causes a shorter hospital stay, and it allows faster patient turnover and increased annual patient load.

New technical advances and scientific progress have led to a progressive reduction of the invasiveness of these approaches and the possibility to access the skull base from the nose has gradually taken place. The trans-sphenoidal approach developed to fit this conceptual way of thinking perfectly, being founded on the possibility of gaining access through natural preconstituted areas, that is, the sphenoid sinus cavity.

The classical indications for endonasal surgery were the pituitary adenomas and some other selected intra-sellar diseases, such as intrasellar, preferably cystic craniopharyngiomas, and intrasellar Rathke’s cleft cysts. Today, the  endoscope has opened the eyes of the surgeon to structures such as the planum sphenoidale, the clivus, the carotid and optic bony protuberances. Pathologies arising or extending in these regions – once approachable only with the more invasive transcranial surgery – such as craniopharyngiomas, tuberculum sellae meningiomas, macroadenomas involving the cavernous sinus and upper clival chordomas, are now also candidates to be removed via the endonasal route.

The endoscopic endonasal procedure is performed using a rigid 0-degree endoscope, 18cm in length and 4mm in diameter, as the sole visualising instrument of the surgical field; sometimes angled scopes are used to further explore the suprasellar area after the lesion removal. Dedicated surgical instruments with different angled tips are needed in order to permit movements in all the visible corners of the surgical field. 

Detailed, complete pre-operative planning, even integrated by three-dimensional computerised reconstruction of magnetic resonance imaging and/or computed tomography scans, is the backbone of the surgical procedure. An image-guided system (neuronavigator) is also required – especially when the classic landmarks are not easily identifiable. This provides information for the midline and trajectory and offers more precision in defining the bony boundaries and the neurovascular spatial relationships.

It is extremely important to use dedicated instruments: different endonasal bipolar forceps, with various diameters and lengths, have been designed to be easily introduced and manoeuvered in the nasal cavity. High-speed, low-profile drills, of sufficient length but not too bulky, are very helpful for opening the bony structures to gain access to the dural space. Finally, it is of utmost importance to use the micro Doppler probe to insonate the major arteries.

The patient is placed supine with the trunk slightly elevated and the head turned 10–15° on the horizontal plane, towards the surgeon. The head is fixed in a rigid three-pin Mayfield-Kees skeletal fixation device only when we use the neuronavigation systems. The surgeon is on the patient’s right side, in front of him/her. The endoscopic equipment and the neuronavigation system are positioned behind the head of the patient and in front of the surgeon. Several adjunctive monitors are placed in various positions in order to allow the members of the surgical team to participate in the operation ergonomically and follow the surgical manoeuveres.

I can certainly say that today the endoscopic endonasal approach to the skull base has greatly increased in popularity and is largely adopted in the main Neurosurgical Centres that perform skull base surgery worldwide. This is testified by the large number of scientific papers found in the pertinent literature, which have been increasingly produced over the recent years. Endoscopy is here to stay and I foresee that it will soon become the standard of care of patients harbouring lesions on the midline skull base. 

There are a number of advantages for the patient and the surgeon.

Benefits to the patient include:

• Less nasal trauma
• No nasal packing
• Less post-operative pain
• Decreased incidence of complications 
• Quick recovery and earlier return to work.

Benefits to the surgeon are:

• A wider and orientable view of the surgical field
• A closer look ‘inside’ the anatomy
• Easier treatment of recurrences
• Increased scientific and research activity
• Promotion of interdisciplinary co-operation.

In the development of our operating room (OR), increasing minimalism is evident: our new room is as simplistic in its architecture as it is complex in its functional capacity. However, the safety of the patient is always the primary goal of the surgical environment. 

Today’s state-of-the-art neurosurgical OR is rapidly evolving, owing to further refinements of current technologies and to the emergence of new exciting front-line developments. Actual possibilities include viewing MRI and CT in the OR at any time and to interact with neuropathologists for real-time microscopic evaluations.

We acquired an integrated OR system with the objective of optimising pre-, intra- and post-operative processes. The new OR saves time and the staff are enthusiastic about it. It improves interdisciplinary teamwork: in fact, the surgeon can also interact with other caregivers (for example, neuropathologists, neuroradiologists) or with observers around the world, in a privacy-safe manner. We think that in this high-tech OR the surgeon can practice in the most optimal way, thereby benefiting him/her as well as the patient because, by adding comfort to competence, it is easier to achieve excellence.

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