Journal of Head & Neck Physicians and Surgeons

: 2020  |  Volume : 8  |  Issue : 2  |  Page : 47--49

Transoral surgery: The developing paradigm of minimally invasive organ and function preserving surgery

Alok Thakar 
 Department of Otolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Alok Thakar
Department of Otolaryngology and Head.Neck Surgery, All India Institute of Medical Sciences, New Delhi

How to cite this article:
Thakar A. Transoral surgery: The developing paradigm of minimally invasive organ and function preserving surgery.J Head Neck Physicians Surg 2020;8:47-49

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Thakar A. Transoral surgery: The developing paradigm of minimally invasive organ and function preserving surgery. J Head Neck Physicians Surg [serial online] 2020 [cited 2021 Apr 18 ];8:47-49
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Many techniques have emerged for transoral head–neck oncosurgery with the promise of being minimally invasive and organ and function preserving, these include transoral laser surgery [TLM], transoral robotic surgery (TORS), and transoral ultrasonic surgery (TOUSS). While these are often portrayed as competing technologies, they are in fact complementary technologies, which all derive their advantages primarily by being in the transoral paradigm. Transoral “inside-out” surgery preserves the pharyngeal architecture, the mucosal sensations, and the coordinated motor swallow and thereby preserve aspiration free swallowing function much better and reliably than with open surgery.

TLM was the first technique and developed primarily for the larynx in the 1980s and 1990s,[1],[2],[3] in an era wherein advanced cancers of the larynx were treated by an organ ablating total laryngectomy, and when the other options of organ-preserving chemoradiation had not yet taken root. The precision of the laser and the magnification of the microscope enabled for close margin resections in the glottis and supraglottis with reliable preservation of swallowing function. The advantages of the transoral route as listed above, and the exceptional precision of the laser accompanied by minimal lateral tissue damage ensured that secondary intention healing was quick with early return of sensate mucosa. This remarkable advance enabling organ preservation for moderately advanced cancers of the larynx has however since been supplanted over the years with the emergence of nonsurgical organ preservation by concurrent chemoradiation.[4] Although there is evidence from centers with expertise that the organ preservation and disease control rates of TLM for moderately advanced cancers are equivalent to and may perhaps exceed the expectation with concurrent chemoradiation,[5],[6] nevertheless, the current trend has been toward restricting TLM to situations with T1, T2, and some T3 cancers with mobile vocal folds and no significant cartilage erosion.[7] This is related to disappointment with the voice outcomes with TLM for more advanced lesions and also perhaps limited transfer of the surgical skills and techniques from beyond the geographical areas where they were initially propagated.

TLM applications extended from the glottis to the supraglottis and subsequently the hypopharynx and the oropharynx. Extensions outside the glottis and larger resections were however accompanied with an increasing incidence of secondary hemorrhage in these sites. Moreover, larger resections required for bread-loaved sectioned resections and this went counter to the established oncological principles of oncosurgery. Apprehensions and criticisms that this may exacerbate lymphatic dissemination or local seeding and compromise oncological cure have been however largely allayed by results demonstrating equivalent cure rates.[8],[9],[10]

TORS was introduced primarily for the oropharynx.[11] It came in the backdrop of an explosion of human papillomavirus-positive oropharyngeal cancer in the developed world, wherein concurrent chemoradiation was offering good cure rates, but survivors were crippled with oropharyngeal dysfunction and swallowing issues.[12] Its promise of treatment de-intensification and morbidity minimization accompanied by the elegance and glamour of delicate intraoral robotic arms controlled by a remote surgeon looking through a three-dimensional (3D) camera captured the imagination of surgeons.[11],[12],[13] On the technical front, it scored over the laser by being not limited by the straight line ergonomics of the laser, the increased maneuverability and dexterity with angled vision scopes and wristed robotic arms with 7 ranges of motion, and the ability to undertake en bloc resections. The diathermy and harmonic energies coupled with the robot offer improved hemostasis with definite advantages in the oropharynx. TORS has become the dominant transoral modality for the oropharynx and is also becoming to be preferred in the supraglottis. The CO2 laser however continues to be preferred for the glottis for reason of its precision, wherein the incision spot size and peri-incisional tissue damage are limited to submillimeter levels.

The initial experience with TORS was modeled on TLM protocols with two-staged operations – one for the primary excision and another second (or occasionally preceding) operation for the neck. Mucosal wounds would be left to heal by secondary intention, and the two stage operation minimized chances of pharyngocervical communications and fistulae. The large raw surfaces in the vascular mucosae of the oropharynx and supraglottis were, however noted to lead to high rates of secondary hemorrhage[14],[15] and the current trend is for a simultaneous or preceding neck dissection which also enables ligation of the lingual or facial artery and so minimizes secondary hemorrhage rates.[14],[15],[16] Single stage operations with simultaneous TORS and neck dissection, however often lead to pharyngocervical communications and therefore necessitate flap reconstruction. Our own preference is to undertake TORS and neck dissection concurrently, with ligation of the relevant artery. On most occasions, we use a superiorly based sternomastoid flap, which we note can reliably plug the pharyngocervical communication.[16]

An additional downside of the transoral bouquet of procedures is with regard to the occasional limitation of transoral access which would naturally limit an effective resection. A preoperative assessment of surgical access may be had by consideration of factors listed in the “LaryngoScore” checklist (interincisors gap, thyromental distance, upper teeth, trismus, mandibular prognathism, macroglossia, micrognathia, range of neck flexion-extension, previous radiation or surgery, Mallampati’s modified score, and body mass index).[17] An alternative is the “Ts” mnemonic (tongue, teeth, tilt, trismus, torus, tumor, treatment, transverse mandibular width, thyromental distance, and BMI > 30).

Extended transoral applications of TORS have included access to suitably positioned parapharyngeal space tumors,[18] and for middle one-third tongue tumors wherein resection requires significant resection of the posterior one-third tongue.[19]

The robot has also been applied to remote access surgical approaches to the thyroid gland, and to neck, submandibular gland, and parotid operations.[20] Remote access allows for hidden incisions which may be positioned as retroauricular, transaxillary, periareolar, or transoral in the lower gingivabuccal sulcus.[21] The philosophy is in contrast to TORS for the oropharynx and supraglottis, wherein the transoral route offers functional advantages related to swallowing preservation. The robot by remote access when applied to the neck structures and the thyroid, however, offers advantages limited only to cosmetic benefits and no functional benefits.

TOUSS has been positioned as an alternative and a replacement to TORS.[22] It is undertaken with a two-dimensional or 3D flexible tip camera scope inserted through the mouth and laparoscopic equipment adapted to transoral applications. High-resolution camera scopes with magnification, and the incorporation of image enhancement with narrow-band imaging to the equipment enables for improved margin assessment at the mucosal margins. The preferred energy source is ultrasonic energy combined with bipolar diathermy, but hybrid techniques involving monopolar diathermy and laser may also be undertaken. The TOUSS instruments do not have the wristed elegance and maneuverability of the TORS instruments, but this can be compensated for by utilizing the entire width of the oral commissure to incline in instruments from very lateral angles. The ultrasonic energy provides for superior intraoperative hemostasis, but problems with secondary hemorrhage as with TORS remain. Similar strategies as for TORS need to be followed so as to incorporate ligation of the arterial supply to the primary tumor, and the use of a flap or sternomastoid muscle plug to avoid fistulae.

TOUSS is becoming an attractive alternative to TORS as it allows for similar surgical resections and outcomes. The slimmer scope and instruments and also the superior hemostasis enable access even in situations of limited mouth opening. The costs of equipment acquisition and disposables are relatively lower when compared to TORS. An additional advantage we have found is greater flexibility for surgical scheduling with TOUSS, as the semi-urgent scheduling requirements of an oncology practice can be challenging with TORS given that it is a shared resource among various departments.

The transoral paradigm has proved itself in terms of improved function preservation and particularly aspiration free swallow preservation in the larynx and oropharynx. Most institutions and practices would however be unable to invest in all three of the technologies listed above. The CO2 laser remains the best tool for the glottis and can also be applied well to the supraglottis, tongue, tonsil, and soft palate. The oropharyngeal sites and the base tongue in particular are however best addressed with TORS or TOUSS.


This material has never been published and is not currently under evaluation in any other peer reviewed publication.


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