Sinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads.

Standing surgery, especially dental procedures, are commonly performed in horses. This leads to an increasing demand for reliable sedation protocols. Therefore, it was the purpose of this study to investigate the influence of butorphanol, midazolam or ketamine on romifidine based sedation in horses during cheek tooth removal. Forty horses presented for tooth extraction were divided in four groups using matched pair randomization. Group R was sedated with romifidine (bolus 0.03 mg/kg, followed by a constant rate infusion (CRI) 0.05 mg/kg/h) and group RB with romifidine (same dose) and butorphanol (0.02 mg/kg; CRI 0.04 mg/kg/h). Group RM received romifidine (same dose) and midazolam (0.02 mg/kg; CRI 0.06 mg/kg/h) whereas group RK was administered romifidine (same dose) and ketamine (0.5 mg/kg; CRI 1.2 mg/kg/h). If sedation was not adequate a top up bolus of romifidine (0.01 mg/kg) was administered. The quality of sedation and the conditions for tooth extraction, the level of ataxia, chewing, head and tongue movement were evaluated by using a scoring system. The investigator was blinded to the applied sedation protocol. Furthermore, serum cortisol concentrations before, during and after the procedure were analyzed to gain more information about the stress level of the horses. Horses in group RM showed significantly less chewing and tongue activity compared to horses sedated with romifidine alone or with butorphanol additionally, but also significantly higher levels of ataxia. The quality of sedation was significantly better if romifidine was administered in combination with ketamine compared to romifidine alone. Furthermore, horses of group RK needed less additional romifidine boli compared to all other groups. Blood cortisol concentrations during surgery in groups RB and RM remained unchanged. Horses of group R showed higher cortisol concentrations during sedation compared to horses of groups RB and RM. Romifidine alone at an initial bolus dose of 0.03 mg/kg followed by a constant rate infusion of 0.05 mg/kg/h was insufficient to obtain an adequate level of sedation and led to increased stress levels, whereas the addition of butorphanol inhibited the stress response. The combination of romifidine with either midazolam or ketamine improved sedation quality and surgical conditions.

Computed tomography (CT) is a well-established imaging technique in the diagnostics of equine sinunasal disease. High-field magnetic resonance imaging (MRI) is becoming more readily available in equine veterinary medicine. MRI is appreciated for its superior ability to depict soft tissues with high contrast. To compare the established technique of CT in the depiction of the equine nasal cavities, paranasal sinuses and adjoining anatomical structures to 3 Tesla MRI the nasal cavities and paranasal sinuses of 13 horses were examined using CT and 3 Tesla MRI. Comparison of CT and MRI images of the paranasal sinuses, nasal cavities and adjoining anatomical structures of 13 healthy horses showed that the inter-rater agreement for the CT examinations was higher than the inter-rater agreement for the MRI examinations. CT images proved to be significantly higher rated for the depiction of cortical bone, while MR images were higher rated for the appearance of soft tissues. For the distinction between different tissues or anatomical structures the MR images were significantly higher rated and especially T2-weighted sequences allowed for a good distinction between delicate structures. None of the MRI sequences produced an exact depiction of the lumen of the nasomaxillary aperture while the CT with a bone window allowed for a satisfying visualization. The CT is an imaging modality that produces high quality images within a short time when examining equine nasal cavities and paranasal sinuses. The strength of CT lies in the high quality depiction of large and delicate structures with high radiodensity. High field MRI with a field strength of 3 Tesla produces images of high quality that allow for the distinction of delicate soft tissue structures but requires long examination times. The high field strength of 3 Tesla magnetic imaging introduces new possibilities in tomographic soft tissue imaging of the equine head but cannot match up with the CT in terms of visualization of bone and total examination duration. Therefore, clinicians should consider the exact imaging needs in clinical cases to decide whether a single examination or a combination of both imaging techniques may promise the greatest benefit for the patient.

Suture exostosis is an intriguing and not uncommon pathology that has to be included in the differential diagnosis for horses with swelling of the head. Although several singular case reports have been published, no large case series is available. The aim of this study is to report a multicentric retrospective collection of suture exostosis cases. Data concerning horses with suture exostosis in the facial region were collected retrospectively. Information regarding breed, age, gender, history, imaging findings, initiated treatment, response to treatment and follow up was recorded. One hundred and five cases of various breeds were reported. Analysis revealed the cases could be grouped into four entities: 45 developed following sino-nasal surgery, 23 following trauma, seven with underlying sinus pathology and 25 idiopathic. Treatment consisted of sequestra removal, plate fixation, antimicrobial and anti-inflammatory drugs or no treatment. Whereas initial localized pain fades within few days or weeks, resolution or reduction of the swelling was obtained in most cases after 3 months to 1.5 years. The etiopathogenesis of suture exostosis seems to consist of different entities. Identification of an underlying cause, particularly the presence of a bone sequester and infection is important to speed up resolution and before concluding an idiopathic case. When performing sinusotomies, it is important to provide as little trauma as possible to the surgical site in order to prevent suture exostosis as a complication.

The objectives of this retrospective study were to describe the prevalence and characteristics of post-operative complications that occur following equine mandibular cheek tooth extractions and to assess for possible associated risk factors. Clinically significant post-extraction complications necessitating repeat referral developed following 20/302 (6.6%) mandibular cheek tooth extractions. Horses developing complications were younger than the overall population having mandibular cheek teeth extractions and the most commonly affected teeth were the Triadan 07 s and 09 s. Alveolar sequestration was the most prevalent complication, occurring in 18/20 horses (90%), with the complete alveolus sequestering in some cases. Post-extraction mandibular fistula formation occurred in 5/20 cases (25%) and mandibular abscessation in 4/20 cases (20%). All cases were successfully treated, including sequestrectomy, and wound debridement with some cases taking up to 5 months for resolution. Anatomical features of the equine mandibular alveoli and bone appears to make them more prone to develop extensive sequestration compared to published complications on maxillary alveolar bone. This requires good pre-operative examination including diagnostic imaging to identify cases of higher risk and thorough risk disclosure toward horse owners as well as owners' compliance.