Acta Neurochir (2013) 155:909–911 DOI 10.1007/s00701-013-1677-1
TECHNICAL NOTE - NEUROSURGICAL TECHNIQUES
Canula-assisted endoscopy in bi-portal transphenoidal cranial base surgery: technical note Michael D. Cusimano & Antonio DI IEVA & John Lee & Jennifer Anderson
Received: 23 January 2013 / Accepted: 24 February 2013 / Published online: 15 March 2013 # Springer-Verlag Wien 2013
Abstract The binasal fully endoscopic transphenoidal approach in skull base surgery requires a specific learning curve and expertise and, even in the hands of experienced surgeons, can be challenging. Quick and efficient endoscopic access can be impeded by factors like a deviated nasal septum and/or very narrow nasal cavity. For this reason, we developed a simple technique to facilitate rapid maneuvering of the endoscope in and out of the nose in the case of a narrow surgical corridor. Using a canula in situ in one of the nostrils, the endoscope can be maneuvered in and out of the nose to rapidly reach the surgical target without inadvertent mucosal trauma that can cause bleeding. This technique is very simple and is particularly helpful for novice neuroendoscopists who are trying to navigate the confines of a narrow nasal cavity, especially when they are assisting more experienced colleagues.
Introduction
Michael D. Cusimano and Antonio Di Ieva contributed equally to this work.
Since the first report of the binasal fully endoscopic transphenoidal approach in 1996 [4], endoscopic transsphenoidal approaches are now used for the treatment of a plethora of skull base pathologies. The first step in this type of approach is the creation of a trans-nasal surgical corridor to the sphenoid sinus. Even in experienced hands, this can be time consuming, given the variability of patient anatomy such as septal deviations and large turbinates, which can hinder quick and efficient entry into the nasal cavity. Obstacles encountered in frequent entry and re-entry into the nasal cavity can obscure the endoscopic visualization and lead to frequent cleaning of the endoscope and make surgery less time efficient. Although irrigation systems exist to facilitate visualization by cleaning the tip of the endoscope, they add to the overall size of the endoscope in an already narrow field, and they do not provide any improved access to the surgical field. The purpose of this paper is to describe a simple technique of using an in situ canula to facilitate rapid maneuvering of the endoscope in and out of the nose in the case of a narrow surgical corridor. This technique provides efficient movement of the endoscope, which can be advantageous to novice neuroendoscopists, by minimizing the chance of inadvertent trauma to surrounding normal nasal tissues.
Electronic supplementary material The online version of this article (doi:10.1007/s00701-013-1677-1) contains supplementary material, which is available to authorized users.
The technique
Keywords Canula-assisted endoscopy . Endoscopic biportal technique . Binostril technique . Skull base . Skull base tumors . Transphenoidal approach . Extended endoscopic approach
M. D. Cusimano : A. Di Ieva (*) Division of Neurosurgery, St. Michael’s Hospital, 30 Bond Street, M5B 1W8, Toronto, Ontario, Canada e-mail:
[email protected] J. Lee : J. Anderson Division of Otolaryngology, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
The initial transnasal surgical approach is performed with a 0° endoscope, with or without the use of the external cover connected to the irrigation system (Clear Vision 2, Karl Storz and Co, Tuttlingen, Germany). The middle turbinates are reduced or lateralized on one or both sides of the nose, depending on the anatomy of each patient. If a nasoseptal
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Fig. 1 a Canula of reusable 5 mm trocar conceived for puncture of the canine fossa (Karl Storz and Co, Tuttlingen, Germany), to be introduced into the left nostril. b The endoscope can be introduced through the canula, to rapidly reach the level of the sphenoidal ostium, the sphenoethmoidal recess, and the sphenoid sinus, without touching/ damaging the nasal walls
flap is required, this is elevated before beginning the sphenoidotomy. Once complete, we proceed with bilateral sphenoidotomies, posterior septectomy and removal of the sphenoid rostrum to create a single opening into the sphenoid sinus. If additional working room is required, bilateral ethmoidectomies are also performed. Two surgeons then start the bi-nostril technique. Fig. 2 a The canula is introduced in the left nostril. Once the canula and endoscope have reached the desired depth of access, the canula can be fixed by means of clamping a simple Alice Forcep to its base. Then the canula is left is situ, for introducing and re-introducing the same endoscope when it requires cleaning of the lens or different endoscopes with different angled lens. b The binostril technique is then used. Different tools can be normally introduced in the right and/or left nostril. c Endoscopic view of the end of the canula before reaching the sphenoid sinus. The endoscope enters without touching or damaging the nasal mucosa and the intranasal structures, in a rapid and effective way
Acta Neurochir (2013) 155:909–911
Throughout the procedure, no nasal speculum is used. If a narrow surgical corridor that limits easy maneuverability of the endoscope is encountered, it is at this time that a canula can be employed. We insert the outer sheath (i.e. the canula) of a reusable 5 mm trocar conceived for puncture of the canine fossa (Karl Storz and Co, Tuttlingen, Germany) (Fig. 1a) into the left nostril, directed toward the sphenoidal sinus. Introducing the endoscope through the canula (Figs. 1b and 2) allows the endoscopist to quickly reach the area of the sphenoid sinus without having to maneuver around any normal nasal structures, which can potentially smear the tip of the lens (Video 1). Once the canula and endoscope have reached the desired depth of access, we fix the depth by means of clamping a simple Alice Forcep to the base of the canula (Fig. 2a and b). Instead of using a metallic canula, one could also use a silicon peel-away disposable catheter, where the external part of the tube can be “peeled” and fixed to the skin of the patient. Other instruments, such as the sucker and curettes, are introduced co-axially to the canula. By this technique, the canula or trocar sheath becomes the “express-way” to quickly reach the level of the sphenoid in a clean way and without touching and/or damaging the nasal mucosa and the intranasal structures (Fig. 2c and Video 1). If some blood enters the canula, it is sufficient to irrigate it with some drops of saline.
Discussion Since the introduction of the endoscope for use in transsphenoidal surgery [1, 4, 6, 10], a number of authors have
Acta Neurochir (2013) 155:909–911
shown the feasibility of this technique to treat a plethora of lesions within the central and paracentral skull base, from the crista galli to the foramen magnum and the first two cervical vertebrae [5, 7, 8]. Since our first case of the endoscopic technique done in 1993, we recognized the advantage of the use in both nostrils (“dualportal technique”), one for visualization with the endoscope and the other for passage of instruments, as opposed to the single nostril technique advocated later by the Pittsburgh group [1, 6]. Almost immediately, we also recognized that the access of the nostril could be constricting, and recommended for the use of a guide in one of the nostrils for easy and rapid insertion and removal of the endoscope [4]. Although the four-handed bi-nostril technique has now become a common practice worldwide [2, 4], the technique of rapid and easy access in and out of the nostril has not been widely described. The bi-nostril approach performed by introducing the endoscope through the canula allows superior maneuverability, flexibility, and efficiency to drive the endoscope into the surgical field, especially when operating in a narrow surgical corridor or when teaching novice endoscopists. The perception of depth and threedimensionality using the 2D endoscopic images can be achieved by the continuous in-out movements of the endoscope [3]. This is particularly useful to some surgeons and novices learning the technique. These maneuvers can be limited by normal intranasal anatomy and from bleeding from nasal mucosa, which reduces visualization. Although cleansing/flushing systems exist to irrigate the lens, this adds an additional financial cost to the surgery. Furthermore, repeated extractions of the endoscope to clean the tip also add valuable time to a case and occasionally delay timely surgical maneuvers. Once the surgical corridor is created, the application of an in situ canula within the nostril allows for the surgeon to quickly move the endoscope from outside the nose into the target surgical field while minimizing inadvertent mucosal trauma. This also allows for a rapid exchange of various angled endoscopes to reach the desired position without navigating through the rest of the narrow nasal cavity. Our technique provides a simple, cost-effective way to address these issues. The trocar that we use as our corridor costs approximately $450 USD. Its introduction into the nostril is very simple and is particularly helpful in advancing novice endoscopists along their learning curve in endoscopic skull base surgery. The technique allows those driving the endoscope to consistently target in on the point of interest every time it is inserted. The technique saves time by keeping the optics clean of any blood, something which may be particularly important for newer 3D endoscopes (such as the Visionsense, Ltd., Petach Tikva, Israel) [9, 11].
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Every technique has its drawbacks. A disadvantage is that the lumen of the present trocar does not allow the introduction of the endoscope with integrated irrigation systems (e.g. Clearvision ®, Karl Storz, Tuttlingen, Germany). Another limitation that the trocar sheath has in common with other irrigation systems is that it adds to the overall diameter of the endoscope, which may limit the introduction of a second instrument through the same nostril. For this reason, we only introduce the canula technique in the case of narrow nasal corridors or with novice surgeons who are learning to drive the endoscope. Improvements to this technique by wider bore or transparent peel-away canulas are clearly achievable and will allow surgeons to further advance the teaching and practice of neuroendoscopy. Disclosure The authors have no personal financial or institutional interest in the devices described in this article.
Conflicts of interest None.
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