The importance of videolaryngoscopy in maxillofacial practice associated with restricted mouth opening in traumatized patients

Orotracheal intubation is considered the most delicate maneuver performed by anesthesiologists, and failure to manage the airways is one of the main causes of possible complications that can be catastrophic during its performance, thus requiring good team planning. Anatomical and / or physiological characteristics, such as limited mouth opening, a condition often found in patients suffering from fractures of the zygomatic arch or who have some abnormality in the temporomandibular joint (TMJ), can characterize a difficult airway, which demands attention greatest of the professional. Therefore, in order to overcome the obstacles that may occur during a difficult or unexpected intubation, new tools have been used, such as videolaryngoscopy in which an intubation device containing miniature video cameras is used in order to allow the operator has an indirect view of the glottis to increase success rates and decrease intubation time. The aim of the present study is to report a clinical case of a trauma victim, with limited mouth opening, who underwent intubation with the aid of a video laryngoscope after failed attempts at conventional intubation.

The patient's mouth opening must be at least 2 cm, and this means that there is enough space to position the blade between the upper and lower teeth. The presence of trismus and problems in the temporomandibular joint can reduce this distance and, consequently, increase the difficulty of visualization and manipulation of important anatomical structures, which can prevent the success of intubation (Erdivanli et al., 2018, Detsky et al., 2019, Turcio et al., 2017, Jungbauer et al., 2009.
Patients suffering from fractures of the zygomatic arch often have limited mouth opening and flattening of the middle third of the face. The zygomatic arch is formed by the temporal process of the zygomatic bone and by the zygomatic process of the temporal bone and in it, the masseter and temporal fascia are fixed (Chang et al., 2012, Trindade et al., 2012, Pereira, et al., 2014. Trismus may result from mechanical impairment of the coronoid process of the mandible, impact on the masseter and temporal fascia, rupture of the fracture of the zygomatic-maxillary complex or even muscle spasms due to fracture of the zygomatic arch (Chang et al., 2012, Trindade et al., 2012, Pereira et al., 2014.
Given this scenario, when conventional laryngoscopes are not satisfactory, videolaryngoscopy is one of the tools that can be used to facilitate intubation in the event of a difficult airway (Ciccozzi et al., 2013, Erdivanli et al., 2018, Kilicaslan et al., 2014, Apfelbaum et al., 2013, Jungbauer et al., 2009, Aziz et al., 2012 and through it, it is possible to obtain a better view of the laryngeal structures, with faster intubations and less need for optimization maneuvers through the use of video laryngoscopes (Ciccozzi et al., 2013, Kilicaslan et al., 2014, Jungbauer et al., 2009, Berkow et al., 2018, Niforopoulou et al., 2010. However, there are still controversies in the literature (Erdivanli et al., 2018& Aziz et al., 2012 whether videolaryngoscopy can increase the success of intubation particularly in the predicted difficult airway, as some studies have limited interpretive value (Aziz et al., 2012& Berkow et al., 2018.
Video laryngoscopes usually have a light source at the tip of their blade and a camera that projects the image in real time to a portable video system, thus, another advantage that can be mentioned, is that they allow to abandon the need for alignment of the oral, pharyngeal and tracheal axes to receive a direct view of the glottis, which facilitates the intubation of patients with pathology or immobilization of the cervical spine (Ciccozzi et al., 2013, Erdivanli et al., 2018, Kilicaslan et al., 2014, Jungbauer et al., 2009, Aziz et al., 2012, Berkow et al., 2018, Niforopoulou et al., 2010.

Methodology
The presente work approaches a case report in a quantitative and qualitative way with the objective of reporting the performance of a videolaryngoscopy after failed attempts in the performance of conventional laryngoscopy, in a patient victim of trauma to the face, with limited mouth opening resulting from fracture in the arch zygomatic. The Free and Informed Consent Term was signed by the patient, following all protocols under the same consent term (Pereira et al., 2018, Delanora et al., 2020.

Case Report
A victim of an accident at work, 15 days ago, suffered a trauma during the installation of a marble statue in the right malar region with a sinking of the region. During the physical examination, a mouth opening restriction of less than 20 mm was found, as shown in Figure 1.  Ac cording to the clinical and tomographic parameters, it was decided to reduce the fracture under general anesthesia.
During intubation, opening restriction proved to be a problem for conventional intubation, Bougie was used for possible tube guidance, but without success. The laryngeal mask was an alternative, however, due to the panoramic view of the covid-19, the option for videolaryngoscopy (Figure 3), coupled to the miller retractor, was introduced through the oropharynx, where the larynx compartments were fully visible.

B A
In Figure 3, it is possible to see the anesthesiologist with the videolaryngoscope inserted in the patient's larynx region, where through the cell phone display it is possible to observe the structures that give access to the trachea, images reproduced by the camera remotely.
The corniculate cartilage was already swollen due to several attempts to introduce the tube. Guided by the video, the bougie was introduced and subsequently intubated with tube number 7. 10 mg of dexamethasone was used to control localized edema and the arch reduction surgery could be performed, returning the zygomatic arch projection and the natural excursion of the coronoid process, without further complications.
The zygomatic arch was repositioned and the patient's mouth opening reestablished. Postoperative computed tomography was requested, which proved the good fracture reduction, as can be seen in Figure 4. In Figure 4, it is possible to observe the reestablishment of the contour of the zygomatic arch, which previously prevented the physiological movement of the mandibular condyle.

Discussion/ Review
The zygomatic arch is a structural component of the zygomatic complex considered one of the most fragile structures of the facial skeleton and responsible for maintaining the anteroposterior projection of the zygoma. Due to their fragility and location, fractures of the zygomatic arch comprise almost 10% of the complex's fractures and can be caused by forces of lesser intensity. Clinically, fractures of the zygomatic arch lead to depression or bulging in the topography of the arch, facial asymmetry, pain and crackling on palpation, limitation of mouth opening by blocking the coronoid process of the mandible, in addition to the formation of edema (Chang et al., 2012, Trindade et al., 2012, Manganello-Souza et al., 2003, Pereira et al., 2014.
As a result of conditions such as this, in which the patient has particularities that can characterize difficult intubation, such as limited mouth opening, it is of fundamental importance that videolaryngoscopy is an alternative available to the anesthesiologist, since it can facilitate the intubation process in function of providing an indirect but more comprehensive view because they have a camera lens close to the tip of the blade closest to the larynx (Ciccozzi et al., 2013, Kilicaslan et al., 2014, Apfelbaum et al., 2013, Jungbauer et al., 2009, Berkow et al., 2018, Niforopoulou et al., 2010. In comparison with direct laryngoscopy, videolaryngoscopy has constantly shown an increase in the success rate of the first pass, with improved laryngeal vision and glottic exposure, in addition to decreased pressure on the teeth and the Research, Society and Development, v. 10, n. 2, e12010212178, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i2.12178 6 strength of intubation (Kilicaslan et al., 2014, Aziz et al., 2012, Berkow et al., 2018, Niforopoulou et al., 2010. The Difficult Airway Society currently recommends that a videolaryngoscope be available whenever there is a need for intubation, although many anesthesiologists are not yet familiar with the equipment and it has a high cost (Berkow et al., 2018).
In a study conducted by Kilicaslan et al. (2014), data from 42 patients whose attempts at intubation with direct laryngoscopy using Macintosh had failed and in which the C-MAC videolaryngoscope was used as the primary rescue device were analyzed. According to the results obtained, videolaryngoscopy with C-MAC has been shown to increase the success rate in cases of unexpected difficult intubation and to improve visualization of the glottis, providing evidence of the clinical effectiveness of videolaryngoscopy in unexpected unsuccessful intubations.
In a prospective randomized controlled trial, Erdivanli et al. (2018) compared the efficiency of the King Vision videolaryngoscope and the Macintosh laryngoscope when used by experienced anesthesiologists in different intubation conditions of adult patients. Regarding successful intubation on the first attempt, laryngoscopes did not show statistically significant differences. However, in terms of time to better glottis visualization and intubation time, the King Vision videolaryngoscope proved to be inferior to the Macintosh laryngoscope.
Although the current evidence still has gaps for this technique to be considered as a standard of care, video laryngoscopes are being increasingly used and considered first-line intubation devices for difficult, rescue and routine intubations, achieving the same or higher success rate compared to direct laryngoscopy and the tendency is for an improvement in the characteristics of the devices until the ideal videolaryngoscope is found (Ciccozzi et al., 2013, Erdivanli et al., 2018, Kilicaslan et al., 2014, Nausheen et al., 2019, Berkow et al., 2018, Niforopoulou et al., 2010.
In summary, it is important to carry out further studies in search of the ideal video laryngoscopes and the main indications for their use, where they bring together the advantages offered by this equipment and are easily accepted by the professional, since its use and handling requires aptitude for such.

Final Considerations
A good planning of the intubation carried out by the anesthesiologist together with the CTBMF team, combined with the availability of new technologies that assist during orotracheal intubation such as videolaryngoscopy, both in public and private services, can be the differential between a successful and intubation an unsuccessful one since muscle relaxants alone are not enough to get around difficult situations. In addition, with good planning, time is saved, physical exhaustion on the part of professionals and a better postoperative result is obtained for the patient, as well as the safety in general of the procedure as a whole.