Laryngeal reinnervation using the spinal accessory nerve: Electromyographic study of the sternomandibularis muscle.

BACKGROUND: Selective laryngeal reinnervation using the first and second cervical nerve (C1C2) is a treatment option for recurrent laryngeal neuropathy that aims to restore the function of the cricoarytenoideus dorsalis (CAD) muscle. Despite the technique's satisfying success rate, it has several limitations. These triggered the search for another potential donor nerve that could reduce CAD muscle fatigue and shorten rehabilitation. The ventral branch of the spinal accessory nerve, providing motor innervation to the sternomandibularis (SM) muscle, was identified as a potentially well-adapted nerve. OBJECTIVES: To gather normative data from SM muscle activity induced by physiological spinal accessory nerve stimulation at rest and during exercise, and to determine SM muscle activity and fibre type recruitment relative to posture, gait and respiratory cycle. STUDY DESIGN: Clinical observational study. METHODS: Surface electromyography (EMG) of the SM muscle was performed in nine horses: trained warmbloods, Thoroughbreds and Standardbreds. Signals were recorded in different feeding postures and at exercise, which included standardised treadmill exercise tests, lungeing and ridden work. RESULTS: Timing of the SM muscle contraction coincided with inspiration at gallop. Intra-individual mean SM muscle activity increased with exercising speed (four times higher in Thoroughbreds at gallop than walk and seven times higher in Standardbreds at high-speed trot than walk). Moreover, the SM muscle was strongly activated at rest when the horse was grazing (seven times more than when it was eating out of a hay net or stable feeder). Frequency domain analysis revealed a predominant type I muscle fibre recruitment during feeding and at exercise (type I muscle fibre activity was at least 2.5 times higher than type II muscle fibre activity). MAIN LIMITATIONS: Lack of reference data on equine EMG. CONCLUSIONS: This study confirmed the potentially advantageous properties of the spinal accessory nerve for laryngeal reinnervation.

Balloon catheter occlusion of the maxillary, internal, and external carotid arteries in standing horses.

OBJECTIVE: To assess the feasibility of balloon catheter occlusion of the internal carotid artery (ICA), external carotid artery (ECA), and maxillary artery (MA) in standing horses. STUDY DESIGN: Experimental and clinical cases series. ANIMALS: Eight healthy horses (phase 1) and 11 clinical cases (phase 2). METHODS: Occlusions were performed on standing horses under sedation and local anesthesia. In phase 1, four horses underwent bilateral ICA balloon catheter occlusion, and four horses underwent balloon catheter occlusion of the ECA and MA. In phase 2, horses were treated by occlusion of ICA (n = 7), ECA (n = 2), or ECA and ICA (n = 2). RESULTS: Internal carotid artery occlusion was successful in seven of eight and seven of nine arteries in phases 1 and 2, respectively. The procedures lasted 53 and 50 minutes, respectively, and catheters were inserted over 13 ± 0.7 cm (mean ± SD). External carotid artery occlusion was successful in seven of seven and four of four arteries in phases 1 and 2, respectively, with mean durations of 31 and 26 minutes, respectively, and a mean distance of catheter insertion of 11.9 cm. Maxillary artery occlusion was successful in five of seven arteries (phase 1), with a mean surgical duration of 47 minutes and a mean distance of catheter insertion of 42.8 cm. CONCLUSION: Balloon catheter occlusion of the ICA, ECA, and MA was achieved in most standing horses. CLINICAL SIGNIFICANCE: Balloon catheter occlusion in standing horses provides an alternative to prevent or treat hemorrhage related to guttural pouch mycosis, particularly in horses in which general anesthesia might pose a risk.

Ex vivo study of minimally invasive procedures for cartilage removal from the metacarpophalangeal or metatarsophalangeal joint and for fetlock tension band application.

OBJECTIVE: To describe reliable minimally invasive procedures for (1) removing cartilage by joint distraction and articular drilling for equine metacarpophalangeal (MCP)/metatarsophalangeal (MTP) arthrodesis; (2) applying a palmar/plantar tension band without MCP/MTP joint luxation. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric equine limbs (n = 12). METHODS: All limbs were used to evaluate the drilling technique. First the MCP/MTP joint was distracted with a 5.5-mm cortical screw. Then, through four stab incisions, articular cartilage was removed with a 4.5-mm drill. Six randomly chosen limbs were then tested for minimally invasive tension band application with a specially designed cannula. Accurate positioning of the tension band was assessed radiographically. All MCP/MTP joints were disarticulated, and the areas of removed cartilage were visually assessed and measured by using planimetry. RESULTS: The mean percentage of removed cartilage was 66.8% ± 7.6% for the metacarpus/metatarsus surface, 67.9% ± 8.6% for the proximal phalanx surface, and 59.5% ± 1% for the two sesamoid bones. The tension band could be accurately placed through four stab incisions with the cannula. CONCLUSION: This minimally invasive technique for cartilage removal was efficient and should be favorable for joint fusion in some clinical situations. The minimally invasive tension band application through stab incisions was feasible and repeatable. CLINICAL SIGNIFICANCE: These procedures should allow total minimally invasive MCP/MTP arthrodesis and be used in selected clinical cases.

Standing Hand-Assisted Laparoscopic Diagnosis and Treatment of a Rare Case of Uterine Adenocarcinoma in an 18-Year-Old Mare.

An 18-year-old French Trotter mare was presented to the Clinique Equine, Ecole Nationale Vétérinaire d'Alfort, for exploration of a 3-month-duration vaginal bleeding. A transrectal ultrasound examination identified a mass within the right uterine horn wall, which had been suspected during transrectal palpation. It was described as a firm heterogeneous intramural mass (7 × 12 cm) in the right uterine horn, located few centimeters cranially to the bifurcation. Hysteroscopy confirmed the ulcerated and irregular shape of the mass. A standing hand-assisted flank laparoscopy was performed to carry out a partial ovariohysterectomy. Two days after surgery, the mare presented with acute and severe signs of colic and was euthanized. Postmortem examination revealed a 720° small intestine volvulus at the mesenteric root, a left dorsal displacement of the large colon, and iliac and tracheobronchial lymph node hypertrophy. Histopathological examination of the removed uterine mass revealed a well-differentiated and infiltrating uterine adenocarcinoma, with lymph node metastasis. Uterine neoplasia, especially adenocarcinoma, is uncommon in the mare and can be successfully removed using a standing hand-assisted laparoscopic technique, which avoids the risks associated with general anesthesia and allows a histologic diagnosis of malignancy. In such cases, though, initial staging and identification of metastasis remain a challenge that will influence the treatment strategy.