Abstract and Introduction
Abstract
The posterior skull base and the nasopharynx have historically represented technically difficult regions to approach surgically given their central anatomical locations. Through continued improvements in endoscopic instrumentation and technology, the expanded endonasal approach (EEA) has introduced a new array of surgical options in the management of pathology involving these anatomically complex areas. Similarly, the transoral robotic surgical (TORS) approach was introduced as a minimally invasive surgical option to approach tongue base, nasopharyngeal, parapharyngeal, and laryngeal lesions. Although both the EEA and the TORS approach have been extensively described as viable surgical options in managing nasopharyngeal and centrally located head and neck pathology, both endonasal and transoral techniques have inherent limitations. Given these limitations, several institutions have published feasibility studies with the combined EEA and TORS approaches for a variety of skull base and nasopharyngeal pathologies. In this article, the authors present their clinical experience with the combined endonasal and transoral approach through a case series presentation, and discuss advantages and limitations of this approach for surgical management of the middle and posterior skull base and nasopharynx. In addition, a presentation is included of a unique, simultaneous endonasal and transoral dissection of the nasopharynx through an innovative intraoperative setup.
Introduction
The posterior skull base and the nasopharynx have historically represented technically difficult regions to approach surgically, given their central anatomical locations. Traditional approaches to this region include creation of an anterior transfacial corridor (Le Fort I osteotomy, maxillary swing, and midface degloving), lateral transcranial corridor (pre- and postauricular infratemporal fossa and subtemporal approaches), and inferior oral or cervical corridor (transcervical-transmandibular or transpalatal approaches). Although these approaches were previously frequently used, they were also associated with high clinical morbidity and less than ideal cosmetic outcomes, which has greatly decreased their use since the advent of the endoscopic, minimally invasive era.
Through continued improvements in the Hopkins rod-lens endoscope (Karl Storz) and endoscopic instrumentation, the expanded endonasal approach (EEA) introduced a new array of surgical options in the management of pathology involving this anatomically complex area. Neoplastic lesions of this area have been successfully resected with favorable outcomes and adherence to oncological principles. However, the pure endonasal route can be inadequate for surgical management of pathology extending beyond the anatomical boundaries, such as for extension below the level of the soft palate in the oropharynx (Table 1). Given these limitations, several institutions initially published studies on their clinical and laboratory experience of combining both the EEA and nonrobotic transoral approach for a variety of pathological processes.
In our initial experience with this combined technique, we successfully repaired oronasal fistulas and surgically managed chronic granulomatous disease, both of which required surgical access through the endonasal and transoral corridors. By combining these windows, a larger operating corridor may be established to obtain surgical margins during resection of neoplastic lesions, while minimizing displacement or dissection of normal tissue in the approach to the area of interest. Although this original, combined technique offered many advantages to utilizing either surgical corridor separately, limitations included significant reduction in simultaneous maneuverability given difficult intraoperative positioning with reduced surgical manipulation and limited vision through the transoral route. These limitations were addressed with the introduction of the transoral robotic surgery (TORS) approach.
Transoral robotic surgery using the da Vinci surgical system (Intuitive Surgical, Inc.) has been extensively described in the literature for the management of middle cranial fossa skull base tumors, along with tongue base, nasopharyngeal, parapharyngeal, and laryngeal lesions. Advantages of TORS include superior 3D visualization, increased instrument access, precise and tremor-free 3-handed surgery, and elimination of external incisions, while limitations include the lack of bone-drilling equipment, relatively bulky instrumentation, and a steep initial learning curve. TORS has been shown to be highly effective in obtaining a direct, illuminated surgical window into the nasopharynx, allowing for surgical management of nasopharyngeal carcinomas and performance of complete nasopharyngectomy. However, without the capacity for bone resection via drilling instrumentation, the pure TORS approach is limited to dissection of soft tissue and may be inadequate to manage involvement of the skull base at the basiocciput region superiorly or medial pterygoid laterally (Table 1). Thus, the next logical step was to combine the EEA and the TORS approach for the greatest possible surgical window with the greatest degree of surgical manipulation (Fig. 1).
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Figure 1.
Illustration of the anatomical corridor and boundaries in the EEA (blue triangle) and the TORS approach (yellow triangle) to the nasopharynx
In this case series, we present our clinical experience with the combined endonasal and transoral approach and discuss its advantages, limitations, and possible future prospects. We also include presentation of a unique, simultaneous endonasal and transoral dissection of the nasopharynx through an innovative intraoperative setup of the endoscopic endonasal and robotic surgical equipment.