Combined transoral transnasal robotic-assisted nasopharyngectomy: a cadaveric feasibility study

June 28, 2017 | Autor: Paolo Castelnuovo | Categoria: Robotics, Feasibility Study, Humans, Feasibility Studies, Clinical Sciences, Cadaver
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Eur Arch Otorhinolaryngol DOI 10.1007/s00405-011-1550-x


Combined transoral transnasal robotic-assisted nasopharyngectomy: a cadaveric feasibility study Iacopo Dallan · Paolo Castelnuovo · Filippo Montevecchi · Paolo Battaglia · Niccolò Cerchiai · Veronica Seccia · Claudio Vicini

Received: 28 October 2010 / Accepted: 14 February 2011  Springer-Verlag 2011

Abstract Surgical management of the nasopharynx is complex. Both traditional and endoscopic transnasal techniques are demanding. Purely transoral robotic nasopharyngectomy has been described but it needs a palatal splitting and is performed with an inferior to superior perspective with a diYcult vision of the upper regions. The aim of this study is to investigate a new robotic surgical setting, which is able to overcome the actual limits. The DaVinci Surgical System was used in two cadavers. Dissection was carried out through a combined transnasal– transoral approach and a purely transoral procedure. A complete nasopharyngectomy was performed with both settings. Working and setting times are comparable. The combined approach avoids palatal spitting and permits a more panoramic view of the surgical Weld with an easier dissection of the upper areas. A robotic palatal sparing nasopharyngectomy is feasible. The combined transnasal–transoral setting seems to oVer signiWcant advantages with respect to traditionally purely transoral procedures. Keywords Robotic surgery · Nasopharyngectomy · Transoral surgery · Combined transoral–transnasal approach I. Dallan · P. Castelnuovo · P. Battaglia Otorhinolaryngologic Unit, University of Insubria, Varese, Italy F. Montevecchi · C. Vicini Department of Special Surgery, ENT and Oral Surgery Unit, Ospedale Morgagni Pietrantoni, University of Pavia in Forlì, Forlì, Italy

Introduction The nasopharynx is one of the most challenging areas of the head and neck and was historically considered surgically unmanageable, given its deep position in the center of the head. The Wrst attempts to overcome this conviction were made in the 80s by means of aggressive external approaches [1–6]. The major disadvantages of external approaches were related to their complexity, their high morbidity and the long hospital stay. More recently, endoscopic techniques have been proposed in alternative to external approaches [7–9], with promising results. Day after day, robotic techniques are becoming an interesting option in the head and neck area. Nowadays, the oropharyngeal region is commonly managed by means of robotic systems and recently a growing interest towards its application in skull base surgery is rising [10–15]. The advantages of the robotic techniques are numerous: robotic surgery provides the Wnest precision in small and conWned spaces, gives a spectacular view of the operating Weld, and its steady and precise movements are less tiring for the surgeon. The robotic arms allow a delicate handling of the tissues, with no adjunctive damage to the surrounding structures. In this paper, we report our preliminary feasibility experience on a cadaver on a novel option to manage the rhinopharynx robotically. A comparison with a purely transoral robotic-assisted procedure is also given and commented on.

Materials and methods N. Cerchiai · V. Seccia (&) 1st Otorhinolaryngologic Unit, Azienda Ospedaliero-Universitaria Pisana, Via Paradisa 3, 56126 Pisa, Italy e-mail: [email protected]

The study was performed at the Robotic Training Lab at the Intuitive Head Quarter, San Francisco, California. Two fresh cadavers were dissected by means of the DaVinci


Eur Arch Otorhinolaryngol

robotic system (Intuitive®) by the senior author (C.V.) with an extensive experience in robotic-assisted surgery. The head was positioned supine without Wxation. No retractor was necessary for the combined transnasal–transoral procedure (CTTP), while a Crowe-Davis retractor was applied in the purely transoral procedure. The setting is the same as described by Lee et al. [12] for a craniocervical junction. The DaVinci® system was placed cranially at the head of the cadaver. A Maryland dissector and a monopolar cauterization device with a spatula tip were used for dissection. The dissection of the nasopharynx was performed through a pure transoral robotic-assisted technique (TORS) on the Wrst cadaver, and through a CTTP, with the optic system placed transnasally, on the second subject. We used a 0° lens and a 30° upward facing lens for the CTTP and for the TORS, respectively. In the TORS, where the procedure is purely transoral, the palatal splitting was mandatory in order to gain an adequate visualization of the rhinopharynx. No dissection was possible without opening the soft palate. In the CTTP, the dissection was possible without any adjunctive maneuver.

Notes on dissection As a preparatory step, in TORS, the splitting of the soft palate was performed before robot setting, while in CTTP no propaedeutic surgical gestures were necessary. However, our personal experience suggests that a posterior nasal septectomy could facilitate the visualization of the Weld of interest. This maneuver is performed before setting the DaVinci system by means of traditional endoscopic endonasal techniques. In clinical cases, when deemed necessary due to pathological conditions, the esophitic portion of the tumor is Wrst removed by means of traditional endoscopic techniques and the site of attachment of the lesion identiWed. Then a posterior septectomy is performed. Obviously, this robotic procedure is not suitable for advanced cases and only a long clinical experience will help us to adequately deWne the real Weld of action of the robotic resection. As of now, we remain cautious regarding the clinical aspects and focus our attention only on purely aspects of technical feasibility. The nasopharyngectomy, with both TORS and CTTP, began with a midline incision in the posterior rhinopharyngeal wall. Then two medial-to-lateral hemi-nasopharyngectomies were performed starting from the midline with a monopolar device. The lateral limit of the resection was represented by the lateral rhinopharyngeal wall, including, to a major or minor extent, the eustachian tube. The assistant provided suction by placing the sucking system transorally or transnasally. By means of this, smoke and secretions are continuously removed from the surgical Weld, thus helping to maintain it clean. The dissection was con-


ducted until the exposition of the underlying bony structures (the clivus and C1) was completed. No dissection on bony structures was performed. By means of an angled lens, it was possible to see the posterior ethmoid and even the pterygoid region.

Results Excellent access to the whole rhinopharynx was obtained in both specimens. The entire nasopharynx was exposed including, bilaterally, the eustachian tube, the Fossa of Rosenmüller, and the clivus. The set up time was 30 min. The 3D visualization was superb with amazing depth perception. The real signiWcant advantage is related to the possibility of performing a “two hands” tremor-free dissection of the anatomical structures. As far as the prospective is concerned, we found that TORS provided an adequate surgical view that was, however, limited superiorly at the level of the superior rhinopharyngeal wall. All the dissection work is performed from an inferior to superior view which is unfamiliar for most surgeons. When working superiorly, at the level of the basisphenoid, it is diYcult to evaluate the Weld correctly because the limit of the surgical Weld corresponds to the borders of the operative space, so that an adequate margin control at the top is not possible (Fig. 1). In CTTP, rhinopharyngeal visualization is signiWcantly improved, and dissection work is done under typical endoscopic vision. By moving the optic system, a more adequate visual control of the surgical margins is easily achieved (Fig. 2). The DaVinci system oVers, through a superb illumination and 3D depth perception, a magniWcent vision even in deeper regions. Working robotic time is deWnitively short; our experience shows that a complete posterior nasopharyngectomy can be performed in less than 10 min with both techniques.

Discussion The emerging interest in robotic techniques in the head and neck area is very evident. Since the pioneering work of the Philadelphia group [16], other regions beyond the oropharynx have attracted the attention of the researchers. The robotic techniques provide the surgeon a true 3D endoscopic vision of the surgical Weld with an accurate depth perception through the use of multiple endoscopes, cameras and dual eye pieces. The robotic system allows multiple degrees of motion and permits an extremely delicate handling of the tissues. The physiologic tremor of the human hand is Wltered and attenuated by the robot. These beneWts are clearly evident when managing deep and hidden regions

Eur Arch Otorhinolaryngol Fig. 1 Approach to the rhinopharynx by means of the TORS. On the left side, the schematic sagittal view of the rhinopharynx and the obtainable surgical Weld, with a 30° lens, is shown. On the right side, the pre-operative image of the nasopharynx is on the top, and the completed nasopharyngectomy is visible at the bottom of the image. The surgical Weld is at the borders of the image on the screen

Fig. 2 Approach to the rhinopharynx by means of the CTTP. On the left side, the schematic sagittal view of the rhinopharynx and surgical Weld is shown. On the right side, the pre-operative image of the nasopharynx is on the top, and the completed nasopharyngectomy is visible at the bottom of the image. By means of a transnasally inserted 0° lens, the surgical Weld and the operating robotic arms are at the center of the screen

such as the nasopharynx. The traditional external approaches to this region are complex, uncommon, and associated with morbidities that are not negligible. Endoscopic transnasal techniques have risen in recent years as a valid alternative, but actually, traditional endoscopic techniques are performed under 2D visualization, and with limited manipulation of the end-eVector of the endoscopic instruments. Newer robotic technologies have opened new questions on this topic allowing the majority of these limits to be overcome. In fact, when compared to open surgical approaches, robotic techniques seem to oVer signiWcant potential beneWts to the patients. As endoscopic techniques, robotic-assisted procedures may avoid a disWguring surgery and can oVer a solution as salvage surgery in recurrent nasopharyngeal disease [17]. Previous robotic experiences on the nasopharynx, both in cadaver and in human beings, are performed with a purely transoral approach plus a palatal splitting [17, 18]. The palatal splitting is mandatory in order to dominate the rhinopharyngeal region and can be associated with more or less signiWcant post-treatment morbidities. These data are conWrmed in our cadaveric

study. Probably, the most critical limit of a purely transoral approach is related to the down-to-up vision that makes working ability less comfortable and thus less safe in the upper regions. For this reason, we tried another solution in order to improve the easiness of the surgical procedure. Based on former experience in endoscopic transnasal techniques [9], we placed the endoscope transnasally. This idea is not new and has been previously described [10]. In this manner, we obtained a familiar and panoramic view of the rhinopharynx and avoided the need to split the soft palate in order to gain adequate space. Furthermore, we reduced the conXict, although minimal, between the robotic arms and the optic system. By comparing a purely transoral approach and a combined transnasal transoral approach these diVerences become evident. Especially with respect to the visualization, the combined solution oVers a signiWcant advantage over the traditional purely transoral procedure. Notwithstanding, a complete nasopharyngectomy can be performed with both TORS and CTTP but, with the former solution, the upper work is performed at the border of the surgical


Eur Arch Otorhinolaryngol Fig. 3 a External view of the head of the cadaver. The robotic arms are placed through a transcervical, paramandibular window. b schematic design of the theoretical position of the trocars and the endotracheal tube during a combined transcervical–transnasal approach to the rhinopharynx. If needed, the endotracheal tube can be Wxed to the dorsum of the tongue by means of stitches (T trocar, ETT endotracheal tube)

Weld, while in CTTP it is possible to easily manage an even more cranial region (Fig. 1–2). Furthermore, during the procedure the optic system can be moved thus increasing the ability to look superiorly or laterally. The use of an angled lens enhances this possibility even more. We underline that our dissection experience has been performed with a 10 mm 0° lens that almost completely Wlls the nasal fossa. Obviously smaller lens will allow a more delicate surgical nasal time. We maintain that combined solutions are probably the best answer to gain adequate space for instruments and optimal visualization in the rhinopharyngeal and upper clival region. Working time to perform a complete nasopharyngectomy is really short. With both solutions, this procedure can be completed in less than 10 min. However, easiness of work, especially in the basisphenoidal region, is greater in CTTP. Although not yet adequately investigated, we trust that with this setting even more cranial regions can be reached. Future on-going experiences will provide the answer to this question. We underline the fact that probably in human beings, CTTP setting does not allow an adequate management of the upper regions simply because it can only be done in edentulous patients and with a signiWcant opening of the mouth. To overcome this limit, when teeth are present, probably a small transcervical, paramandibular window would allow the placement of robotic arms for correct rhinopharyngeal management (Fig. 3). This solution was performed on the basis of a previously described idea [19]. From a technical viewpoint, the placement of transcervical paramandibular trocars is done by performing a small paramandibular incision (
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