Feline skull injuries: treatment goals and recommended approaches

Dear Editors, – We read with interest the article by Drs Cristina Rizkallal and Pilar Lafuente entitled ‘Feline skull injuries: treatment goals and recommended approaches’. ¹ This article appears to be a narrative review that aims at explaining the existing knowledge on perspectives and management of maxillofacial injuries in cats. One of the valuable aspects of a review paper is that it presents a summary of the scientific literature so that the readers can form an idea about the existing and current knowledge to enhance patient care. Unfortunately, we found this paper to contain (1) terminological inaccuracies; (2) historical treatments that are no longer recommended and widely accepted; (3) a lack of understanding of certain disorders; and (4) minimal information on the current standard of care in feline maxillofacial fracture management. The end result is that the journal’s readership was not exposed to the most updated and scientifically sound information.

• Nomenclature and anatomical descriptions The authors use the term ‘hemimandible’ on several occasions. According to Nomina Anatomica Veterinaria and leading veterinary anatomy books, most animals, including cats, have two mandibles (not hemimandibles), one on each side.^2,3 On the same note, the mandibular canal contains the inferior alveolar artery, vein and nerve (ie, the neurovascular bundle), not the ‘mandibular alveolar artery’ or the ‘inferior mandibular nerve’. Also, there are no ‘premaxillary bones’, these are the incisive bones. In addition, the articular cartilage of the temporomandibular joint (TMJ) is not made of hyaline cartilage but a fundamentally different fibrocartilaginous tissue, with a fibrocartilaginous disc separating the joint into two non-communicating compartments.^4,5

• Mandibular body fractures The authors discuss two main options: interfragmentary wiring and plate fixation. They do not discuss or provide images of one of the most common methods of repair: interdental wire and composite splint (ie, a minimally invasive approach).^6,7 With regards to using internal fixation, it is unfortunate that the authors mention the use of general orthopedic and mostly stainless steel plates (eg, dynamic compression plates and locking compression plates). In fact, the mentioned plates are not recommended for use in the oral and maxillofacial region.^6,8 This is largely due to the fact that, in contrast to stainless steel, titanium miniplate systems are designed for maxillofacial fractures in humans and are an effective means for internal fixation of mandibular and maxillofacial fractures in cats and dogs. Importantly, titanium miniplates have a modulus of elasticity and density similar to bone and enable osteointegration with the underlying bone. ⁹ Furthermore, the biomechanics and ideal placement of locking titanium miniplates for repair of mandibular fractures in cats has been thoroughly established, published and practiced.^8,10 Unfortunately, none of this information is conveyed in this review paper. The use of an external fixator in cats, as mentioned and illustrated in the manuscript, may be a common practice in the authors’ experience but is certainly not widespread. In fact, external fixation, as demonstrated in Figure 1l of the manuscript, with 12 pins, some crossing from side to side, is highly likely to result in dental and neurovascular damage, pain and interference with tongue function, with little scientific evidence to support its use.

• Maxillary fractures We contest the statement describing that for large defects in the hard palate an interfragmentary pin with or without a figure-of-eight wire is ‘the treatment of choice’. This is not the case; it is merely the authors’ opinion.

• Temporomandibular joint fractures and disorders The authors describe a ‘locking-jaw syndrome’, a clinical entity that is actually known as TMJ dysplasia. This is not a syndrome but a clinical disorder that results in ‘locking’ of the coronoid process on the zygomatic arch due to excessive laxity of the TMJ (ie, due to dysplastic changes).^6,11 In addition, currently, removal of maxillofacial bones, as described for the zygomatic arch, should be performed with precision osteotomy devices, such as instruments used in piezoelectric bone surgery, not with rongeurs. ¹² It is also not clear how this non-traumatic skull entity has made its way into this manuscript on skull injuries.

The use of rigid or elastic maxillomandibular fixation, the most common and appropriate fixation for TMJ fractures, is minimally explained and illustrated.^6,7 Instead, the authors extensively describe the bi-gnathic encircling and retaining device (BEARD) technique, which was reported in 2010 and is not commonly used or published in leading textbooks. ¹³

Finally, we acknowledge that there are various approaches to treat maxillofacial fractures in cats and we invite the authors to review the current scientific literature and recently published books that are referenced in this letter. We believe that this literature deserved to be acknowledged by the authors and described to the readership of the journal.

Boaz Arzi DVM, DAVDC, DEVDC, Founding Fellow AVDC Oral and Maxillofacial Surgery Associate Professor, Department of Surgical and Radiological Sciences, University of California, Davis, CA 95616, USA Nadine Fiani BVSc, DAVDC, Founding Fellow AVDC Oral and Maxillofacial Surgery Assistant Clinical Professor, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA Santiago Peralta DVM, DAVDC, Founding Fellow AVDC Oral and Maxillofacial Surgery Assistant Professor, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA Frank JM Verstraete DrMedVet, BVSc, MMedVet, DAVDC, DECVS, DEVDC, Founding Fellow AVDC Oral and Maxillofacial Surgery Professor, Department of Surgical and Radiological Sciences, University of California, Davis, CA 95616, USA