Alternative intubation techniques for oromaxillofacial surgery in dogs and cats

Advanced oromaxillofacial surgeries in dogs and cats present unique challenges in anesthetizing the patient, particularly regarding airway management and intubation. Traditional (routine, orthograde, or normograde) endotracheal intubation techniques may not always be feasible or optimal due to anatomical constraints and limiting surgical access. In such cases, alternative intubation techniques have emerged as valuable alternatives, offering improved access, reduced risk of complications, and enhanced surgical outcomes.

The first aim in maxillofacial trauma repair is to restore the pre-trauma occlusion, allowing patients to comfortably resume masticatory functions(1). Routine intubation typically impairs the evaluation of occlusion intra-operatively. In addition, temporary maxillomandibular fixation (MMF) has become the standard of care when patients undergo open reduction and internal fixation (ORIF) for trauma that resulted in a malocclusion(1). In addition, temporary MMF allows the surgeon to proceed with ORIF without the need to intermittently assess occlusion. A normograde intubation followed by a pharyngotomy or transmylohyoid intubation overcomes these challenges that exist with temporary MMF and bypasses the oral cavity optimizing surgical outcome(2,3). The decision to use a transmylohyoid over a pharyngotomy intubation is operator preference. The latter has a more hostile surgical work environment due to the close proximity of the maxillary and linguofacial veins, external carotid artery, vagosymphatetic trunk, and the recurrent laryngeal nerve. These techniques can also be used for patients that undergo reconstruction of the mandible after oncologic surgery with a staged or immediate reconstruction. In these reconstructive cases, as well as patients that have bilateral mandibular fractures a pharyngotomy intubation may be preferred as the transmylohyoid intubation technique may limit the surgical field.

On the contrary, pathologies that result in a restricted range of motion of the TMJ possess a different set of challenges when normograde intubation is not feasible. Restricted range of motion of the TMJ could be the result of pathologies directly related to the TMJ such as TMJ ankylosis or pseudoankylosis. Other differentials include oral foreign body, retrobulbar disease, neoplasia, zygomatic sialocele, and masticatory muscle myositis (MMM). Masticatory muscle myositis, an immune mediated condition that attacks type 2M muscle fibers, is known to cause inflammation of the masticatory muscles in the acute stage and atrophy with fibrosis of these muscles in the chronic stage, both of which result in reduced range of motion or in severe cases even total inability to open the mouth. For these patients an endoscopy guided intubation or retrograde intubation may circumvent these difficulties(4,5).

Lastly, a temporary tracheostomy should be reserved for patients where all other options have been exhausted due to the significant morbidity and relatively high complication rate associated with this technique(6,7).

REFERENCES

1. Boudrieau RJ, Verstraete FJM: Principles of maxillofacial trauma repair, in FJM Verstraete, MJ Lommer (eds): Oral and maxillofacial surgery in dogs and cats. London, UK, Saunders Elsevier, 2012, pp 233–242
2. Soukup JW, Snyder CJ. Transmylohyoid Orotracheal Intubation in Surgical Management of Canine Maxillofacial Fractures: An Alternative to Pharyngotomy Endotracheal Intubation. Veterinary Surgery (2015) 44:432–436. doi: 10.1111/J.1532-950X.2014.12138.X
3. Lantz GC. Pharyngotomy and pharyngostomy. in FJM Verstraete, MJ Lommer (eds): Oral and maxillofacial surgery in dogs and cats. London, UK, Saunders Elsevier, 2012, pp 543–546
4. Vieitez V, Ezquerra LJ, López Rámis V, Santella M, Álvarez Gómez de Segura I. Retrograde intubation in a dog with severe temporomandibular joint ankylosis: Case report. BMC Vet Res (2018) 14:1–6. doi: 10.1186/S12917-018-1439-7/FIGURES/1
5. Abdoon ASS, Soliman AA, Fathalla SI, Gadallah S, Kandil OM, Shaalan AH. Cheap and easy use of a video laryngoscope as a guide for endotracheal intubation in dogs. Bull Natl Res Cent (2019) 43: doi: 10.1186/S42269-019-0178-7
6. Guenther-Yenke CL, Rozanski EA. Tracheostomy in cats: 23 cases (1998–2006). J Feline Med Surg (2007) 9:451–457. doi: 10.1016/J.JFMS.2007.06.002
7. Nicholson I, Baines S. Complications associated with temporary tracheostomy tubes in 42 dogs (1998 to 2007). Journal of Small Animal Practice (2012) 53:108–114. doi: 10.1111/J.1748-5827.2011.01167.X