Transoral Robotic Surgery - An Inevitable Future of Oral and Maxillofacial Surgery

Introduction

Surgeries in the oral and maxillofacial region have long been performed using conventional open surgical techniques with intra/extra oral incisions, either through a transpharyngeal or transmandibular approach. The difficulties encountered in the conventional procedure include limited accessibility and inadequate visualization of the surgical space, along with associated impairments, blood loss and site morbidity.

With the aim of providing an alternative technique to conventional procedure, advancements in this field have led to the development of minimal invasive techniques. Minimally invasive procedures have gained momentum over the past two decades and have evolved significantly. With this vision of minimal invasiveness, ‘Transoral Robotic Surgery’ (TORS) was proposed and introduced in 2004-2005.

TORS is one of the latest advances in the treatment of tumors of head and neck region via direct access through oral cavity. Since its introduction, TORS has gradually evolved and gained popularity due to its numerous advantages over conventional procedure. The advantages of this technique include - being minimal invasive, fewer complications encountered, adequate visibility, reduced blood loss, improved esthetics as extra oral incisions are not required, and shorter hospital stay.¹

McLeod and Meldar were the first to introduce this technique clinically.² They applied TORS for excision of vallecular cyst. A surgical robot was used for visualization of structures in the oropharyngeal region and for gaining adequate access without the need of incision over chin, lip, neck regions.³ Scope of TORS include management of malignancies and tumors of head and neck region, management of cases of obstructive sleep apnea, in radical tonsillectomy procedure, for resection of tumors in pharyngeal region above the level of larynx, for hemi-glossectomy, etc.⁴ TORS proved to be a promising treatment technique in these conditions with minimal complications.

History

Transoral Robotic Surgery was developed by Bart O’ Malley and Dr. Gregory Weinstein at the University of Pennsylvania.^5,6 Research conducted by them demonstrated the safety and efficacy of TORS approach and proved its efficacy in the treatment of cancers without potentially devastating complications.^7-9 In 2009, FDA approved TORS and the Da Vinci system was permitted to perform TORS for stage T1 and T2 cancer of oropharynx.^10-12

Robotic surgery system can be described as an information system, with an input analysis part consisting of various biologic and chemical sensors, imagers, and an output part consisting of devices such as lasers and manipulators. These parts act as a teleoperation system with human being interposed between them.^13,14 Puma 560 was the first robotic surgery system introduced, which was subsequently followed by three other systems viz. Generation 1: AESOP (Automated Endoscopic System for Optimal Positioning), Generation 2: Telerabrot Zeus, Generation 3: Da Vinci Surgical System, which is currently a widely accepted system with high success rates.¹⁵ Generation system was the first system employed in oral and maxillofacial surgery for various surgical procedures involving head and neck region, after its approval by FDA in 2009.^{2, 3}

Procedure

Anesthesia is administered with patient to patient in a supine position. Retractor is used to gain access to the mouth, and the robotic camera and surgical instruments are inserted and guided into patient’s mouth via da Vinci patient side cart. The patient’s throat is viewed through a three-dimensional view finder, and the robotic instrument is then guided inside the mouth with the surgeon controlling and manipulating the instrument for procedure completion. Resection of tissues is achieved and suturing is completed.¹⁶

Da Vinci surgical system^17,18

The da Vinci Surgical System is a surgical robotic system developed by the Intuitive Surgical American company. In 2000, it was approved by FDA. It is designed to facilitate minimal invasive surgical approach and is controlled by a surgeon from a console. According to the manufacturer, the da Vinci System is called "da Vinci" in part because “The Study of Human Anatomy of Leonardo da Vinci” has eventually led to the design of the first known robot in history.

The da Vinci System includes a surgeon's console situated in the same room as the patient, and a patient side cart equipped with three to four interactive robotic arms (based on the model). These robotic arms are controlled by the surgeon from the console. The arms are for tools that hold objects, and can act as bovies, scissors, scalpels or graspers; the final arm controls the 3-D cameras. The surgeon operates the console's controls to maneuver three or four robotic arms of the patient-side cart. The da Vinci System always requires a human operator to function.

Clinical applications

TORS in the management of malignant and benign oral and oropharyngeal tumors

TORS is a highly advantageous procedure in terms of conservative management of such highly invasive tumors. It is an excellent substitute to the conventional management with invasive open surgical procedures and chemotherapy which may cause serious complications. In TORS technique, extra oral incisions are avoided, preventing secondary infections and it is also a time saving procedure.^19,20

Multiple studies signify that use of TORS in the management of recurrent malignancy in oral cavity, nasopharynx, oropharynx resulting in a higher recovery of function, recurrence free survival and higher negative margin rate. Also, it has been observed that with TORS, there is a decrease in risk of hemorrhage, and a reduced intra and post operative dependency on tracheostomy and gastrostomy tube.^20-22

Byrd. J. Kenneth et al., in their study demonstrated a 94.5% and 91.8% two-year disease specific survival and locoregional control of cancer, respectively.²³

In another study by Iseli Tim et al., among 62 patients, about 69% resumed oral intake prior to discharge and about 83% resumed within two weeks after discharge.²⁴

TORS is reported to be efficacious in identifying undiagnosed primary neoplasms.^24,25

A study by Park et al. revealed that TORS lead to decreased postoperative anxiety and pain, resulting in better patient compliance and improved appetite.²⁶

TORS in the management of Obstructive sleep apnea

In obstructive sleep apnea, TORS facilitates increase in the size of air way, either by removal of adenoids, tonsils, uvula or by sectioning the base of tongue.

In a study by Thaler et al. in 2016, an average decrease of forty five percent in the apnea-hypoapnea index was observed post TORS, among the 75 patients studied.²⁷

In another study conducted in 2015 evaluating the swallowing outcome after TORS for sleep apnea among seventy-eight patients, after about 1.05 days post operating with TORS, oral feeding was resumed and no long-term swallowing issues were noted.²⁸

TORS in cleft palate and cleft lip management

Although the use of robotic surgery in the treatment of cleft lip and palate is still emerging, the results of the studies conducted so far seem to be promising.

A study by Khan et al.in 2015 reported the feasibility of robotic intraoral cleft surgery in human cadavers.²⁹

Nadjmi reported increased operative time with robot assisted surgery and according to him, it was the accurate dissection protocol of TORS that causes prolonged duration.³⁰ Precise dissection reduces the risk of damaging the surrounding vascular tissues.

TORS in neck dissection cases

Robotic surgical system in radical neck dissection was first put into application by Kang et al. but it was not proved to be more beneficial compared to conventional approach in terms of intra operative bleeding control, retrieval of lymph nodes and related complications.³¹

TORS in craniofacial asymmetry cases

Chen et al. in 2010 used robot MOTO-MAN for bone cutting and grinding through the inbuilt programed navigation system, but not much promising results were obtained and thus use of TORS in craniofacial asymmetry cases remains under experimental stage.³²

Additional potential benefits of TORS include

• Excellent cancerous tissue resection

• Decreased loss of blood and decreased pain

• Decreased infection risk

• Shorter stay at hospital

• Quicker recovery time and return to daily activities

• Better function preservation

• Minimal cosmetic changes

Conclusion

Transoral robotic or robotic surgical technique is a minimally invasive novel system with promising impact. However, its development and application are still at an early stage. Further refinements are important so as to make it applicable on a broader sense facing all the challenges. From a clinical standpoint, transoral robotic surgery is an inevitable advancement and its primary outcome in the head and neck region include good control over the lesion, early post-operative functional recovery, accurate resection of diseased tissues and reduced surgical morbidity. However, its broader application in the head and neck region for managing various cases will require more research and more accurate and optimized robotic machines in the future.

Conflict of Interest

None