Exoscope-assisted oropharyngeal surgery

6.1

Introduction

The oropharynx is currently one of the most affected sites in head and neck oncology. Over the past 20 years, the incidence of oropharyngeal cancer has increased significantly, especially in younger people. This trend is clearly related to previous human papillomavirus infection.

For advanced-stage oropharyngeal cancer, treatment generally includes at least two therapeutic modalities (surgery followed by radiation therapy or concurrent chemoradiotherapy), whereas for early disease treatment consists of surgery or radiation therapy alone. Radical surgery is particularly challenging because the oropharynx is involved in the crucial functions of swallowing, breathing, and speech, therefore early-stage cancers are frequently treated by radiation therapy alone.

Historically, oncologic oropharyngeal surgery has been limited to open approaches (lateral pharyngotomy, pull-through, transmandibular approach), allowing excellent direct access to the disease, resulting in considerable functional and aesthetic sequelae. Therefore, nonsurgical organ preservation therapeutic options have progressively gained ground over time, guaranteeing similar oncological results, net of less invasiveness, and reduction of the impact on quality of life.

Following an initial enthusiastic spell, treatments based on chemoradiation protocols also demonstrated a significant rate of long-term dysfunctional sequelae, in turn extremely debilitating with a worsening of perceived quality of life. There was therefore a need to improve the options for surgical treatment allowing oncological and functional results similar to nonsurgical options to be obtained and minimizing the morbidity and the burden of treatments. This led to the development of minimally invasive transoral surgical techniques, such as laser and robotic surgery.

The recent introduction of 3D exoscopic surgery introduced interesting technical improvements in head and neck surgery, especially in transoral surgery, with the aims of replacing robotic surgery and minimizing the costs of the procedures.

In 2020, we have coined the term 3Dees (3D exoscopic/endoscopic surgery) to describe the use of the 3D VITOM Exoscope System/3D optics (Karl Storz, Tuttlingen, Germany) for the treatment of tumors of the oropharynx and oral cavity at an early-intermediate stage and to treat benign pathologies. Our aim has been to develop and rejuvenate the traditional transoral surgical technique with the addition of 3D screen vision, to analyze the efficacy and safety of the surgical procedures, and to test the system's ability in terms of surgical precision and shared surgical vision in comparison to transoral robotic surgery (TORS).

6.2

History

In 1951, Huet first described the transoral lateral oropharyngectomy (TLO) procedure for treating early invasive squamous cell carcinoma (SCC) of the tonsillar region. TLO was reported to be an effective treatment option with safe oncologic outcomes for tumors of the lateral oropharyngeal wall, and it could represent an alternative to traditional aggressive surgical procedures, such as the transmandibular or transpharyngeal approaches.

Lacourreye et al. reported 5-year local control rates of 89%–89.6% and 81.7%–85.8% in T1 and T2 oropharyngeal cancer treated with TLO, respectively. Moreover, other Authors reported 80% local control rate for selected oropharyngeal T3 and T4a. ^, Nevertheless, Huet's procedure did not achieve widespread acceptance among head and neck surgeons due to the narrow surgical field, which was difficult to reach because the first surgeon's view was limited (many tonsil and pharyngeal cancers are difficult or impossible to reach through the mouth under direct vision), and the poor maneuverability of surgical instruments.

In 2003, Steiner attempted to overcome the drawbacks shown by TLO by introducing the use of microscope and transoral laser microsurgery (TLM) for the resection of oropharyngeal tumors, giving the surgeon better magnification and illumination of the surgical field. Although this was a significant improvement in transoral surgery allowing surgeons access to oropharyngeal sites that were hard to reach without an open approach, the microscope does not allow viewing around corners (it cannot be rotated along three-dimensional axes) while the 3D view is restricted to the first operator. In addition, it is only possible to execute straight/tangential cutting lines with the CO ₂ laser, limiting the ability to make angled cuts around bulky structures or tumors.

To improve the efficacy of transoral access able to avoid the limitations of TLM, surgeons investigated the potential of surgical robotic platforms. TORS was performed for the first time in 2005 by Hockstein and colleagues, ^, while the earliest series of outcomes were published later by Weinstein, O'Malley, and colleagues. ^,

In recent years, several studies have shown that TORS may be an effective alternative to open surgery. The high-resolution, magnified three-dimensional view of the operative field provided by TORS allows excellent visualization of the target area. Many other advantages have been highlighted: stable three-dimensional binocular magnification allowing “en bloc” resection to be performed with better identification of nerves and vessels; motion scaling; tremor filtration; a shortened learning curve and superior ergonomics for the surgeon. Moreover, surgery-associated morbidity is reduced with the robotic technique, improving functional outcomes compared to open approaches, and length of hospitalization is also reduced.

However, TORS faces some obstacles in pharyngeal and laryngeal surgery because the introduction of the robotic arms and instruments into narrow cavities can be difficult. Tumor exposure can be inadequate and can interfere with the robotic arms, and airway management can be challenging. In addition, the surgeon does not experience any intraoperative tactile feedback with this approach. Finally, robot-assisted surgery is costly with great obstacles to widespread uptake of this surgical option. Not all institutions have Da Vinci robotic platforms (Intuitive Surgical, Sunnyvale, CA), and there is often competition for the system among different specialties. Most hospitals cannot afford to purchase such an expensive device, particularly in developing countries.

6.3