Evaluation of the effect of laser salpingopharyngostomy on the guttural pouch environment in horses.

BACKGROUND: Laser salpingopharyngostomy has been used as an adjunct to primary medical therapy allowing for topical debridement, topical treatment or to potentially alter the guttural pouch environment in horses with guttural pouch disease. OBJECTIVES: To evaluate the effect of a laser salpingopharyngostomy on the guttural pouch environment in healthy horses. STUDY DESIGN: Experimental study. METHODS: In six adult Standardbred female horses, under standing sedation a stab incision was made ventral to the sternocephalicus tendon and a customised trocar inserted into the medial guttural pouch compartment. Baseline (day 0) temperature, humidity, oxygen (O2 ) and carbon dioxide (CO2 ) levels were recorded. A laser salpingopharyngostomy was subsequently made into the right guttural pouch. The guttural pouch environment was re-sampled as above on days 7 and 14 to detect differences in the local environment of the guttural pouch caused by the laser salpingopharyngostomy. RESULTS: The guttural pouch environment was altered by the laser salpingopharyngostomy. Baseline recorded values within the guttural pouch were highly constant within each horse. Post laser salpingopharyngostomy there was considerable variation within the guttural pouch between horse and during the period of sampling. Specifically, CO2 levels post laser salpingopharyngostomy appeared to be linked directly to the horse's respiratory pattern with peaks and troughs recorded post laser salpingopharyngostomy. The variation in CO2 was significantly different at days 7 and 14 post laser salpingopharyngostomy compared with baseline levels (day 7 = 6 mm Hg, day 14 = 8.83 mm Hg). Oxygen levels were also more varied during sampling compared with baseline (day 7 = 3.4%, day 14 = 1.83%). There was no change in humidity or temperature during the study. MAIN LIMITATIONS: This study was conducted on horses with no evidence of guttural pouch abnormalities or disease. CONCLUSIONS: Laser salpingopharyngostomy alters the guttural pouch environment and this may be useful in the treatment of guttural pouch disease where this alteration is desirable.

Management of an extensive equine juvenile ossifying fibroma by rostral mandibulectomy and reconstruction of the mandibular symphysis using String of Pearls plates with cortical and cancellous bone autografts.

OBJECTIVE: To describe a surgical technique for rostral mandibulectomy and reconstruction of the mandibular symphysis. STUDY DESIGN: Case report. ANIMAL: One 5-month-old warmblood cross filly. METHODS: A preoperative diagnosis of a juvenile ossifying fibroma was made on the basis of clinical appearance and was later confirmed via histology. The tumor was large, rapidly growing and extending to the caudal aspect of the mandibular symphysis. Computed tomography was performed for surgical planning. The tumor was excised by performing a mandibulectomy caudal to the symphysis. The mandibular symphysis was reconstructed with String of Pearls (SOP) plates. Cortex screws placed in lag fashion, a cortical bone graft from one of the mandibles and a cancellous graft harvested from the tuber coxae. RESULTS: At 9 months of age there was no sign of tumor reoccurrence, the implants were removed because of infection and the mandible had formed a new stable symphysis. The horse was able to prehend food and masticate normally. The owner was pleased with the cosmetic and functional outcome. CONCLUSION: The described surgical technique is a viable option for mandibulectomy and reconstruction of the mandibular symphysis. The technique provided adequate stability for healing to occur in the face of infection. CLINICAL SIGNIFICANCE: Neoplasia and other conditions affecting the entire mandibular symphysis can be treated by complete surgical excision and reconstruction.