Transendoscopic laser treatment of guttural pouch tympanites in eight foals

Endoscopic Anatomy of the Equine Guttural Pouch: An Anatomic Observational Study

Guttural pouch endoscopy allows for both the visualization and treatment of many clinical problems in the equine retropharyngeal region. This area is extremely complex, and its description remains a real challenge for veterinary anatomists and practitioners. Six clinically normal equine cadavers were employed. Conventional dissections of guttural pouches without penetrating the guttural pouch membrane were first performed, and each adjacent structure was identified. Then, a guttural pouch endoscopic exam of the dissected heads was performed in order to correctly map each visible underlying anatomic structure identified in the previous dissection. This allowed us to: 1-identify each structure visible on endoscopic examination of the guttural pouch; 2-create a representative map of all the structures accurately identified via endoscopy; and 3-describe a systematic guttural pouch endoscopic examination with practical keys to help identification of the underlying vital structures. Our investigation provides new practical information on guttural pouch endoscopic anatomy and has allowed us to identify structures that were not previously described. We believe that this information may help with an accurate diagnosis in some cases and also potentially reduce iatrogenic trauma to important structures.

Surgical Treatment of a Retropharyngeal Abscess in a Japanese Black Cow

Simple Summary

Causes of inappetence and dysphagia in cow include swallowing foreign bodies, such as a magnet or a sharp object, or trauma to the posterior pharyngeal area during oral administration. The cow in this case had formed a large abscess in her pharynx that obstructed the entrance to her trachea, although the cause was unknown. By using ultrasound equipment to check the thin walls of the abscess and the distribution of blood vessels, a hole was drilled in the appropriate area, which allowed the internal pus to drain and heal. Ultrasound diagnostic equipment is useful in diagnosing abscesses deep inside the body.

Abstract

A 17-month-old Japanese Black cow presented with inappetence, wheezing, dysphagia, and drooling. Radiography and ultrasonography revealed an oval, dorsal, pharyngeal mass, with an internal horizontal line demarcating the radiolucent area from the radio-opaque area. Upper airway endoscopy revealed pus-like deposits in the dorsal nasal passage, hyperemia, and edema in the dorsal pharynx, leading to swelling and airway obstruction. Manual palpation, after sedation, revealed a thickened mass surface, which was difficult to rupture with manual pressure. After inserting a linear sonographic probe through the mouth to establish the vascularity surrounding the mass and to identify a relatively thin-walled area, a trocar was pierced into the mass under endoscopic guidance, and the opening was enlarged manually. The mass was filled with stale pus-like material, which was removed manually. The abscess cavity was washed using saline and povidone–iodine. Day 1 post-surgery, dysphagia and wheezing disappeared. Day 16 post-surgery, endoscopy showed significant improvement in the airway patency. One year postoperatively, the owner reported that the cow had an uneventful recovery. For deep abscesses, such as bovine pharyngeal abscesses, it is important to perform a preoperative transoral Doppler ultrasonography to assess the vascularity and thickness of the abscess wall for safe trocar insertion and abscess drainage.

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.

Comparison of two techniques for transpharyngeal endoscopic auditory tube diverticulotomy in the horse

Auditory tube diverticula, also known as guttural pouches, are naturally occurring dilations of the auditory tube in horses that communicate with the nasopharynx through a small ostium. Infection and select other conditions can result in inflammation and narrowing of the nasopharyngeal ostium, which prevents drainage of fluid or egress of air and can lead to persistent infection or guttural pouch tympany. Auditory tube diverticulotomy allows continuous egress from the auditory tube diverticula and is a feature of disease treatment in horses, in which medical treatment alone is not successful. Transpharyngeal endoscopic auditory tube diverticulotomy was performed using a diode laser either at a single dorsal pharyngeal recess location or bilaterally caudal to the nasopharyngeal ostium in 10 horse head specimens. Both methods resulted in clear communication between the nasopharynx and auditory tube diverticula. Diverticulotomy performed in the dorsal pharyngeal recess required less laser energy and activation time and had a shorter surgical duration than diverticulotomy performed caudal to the nasopharyngeal ostium. Further study related to the clinical application of both techniques is warranted.

Update on disorders and treatment of the guttural pouch

The most common disorders of the equine guttural pouches are empyema, tympany, mycosis, and temporohyoid osteoarthropathy. Diagnosis of these conditions is made primarily by imaging with endoscopy, radiographs, computed tomography, and/or MRI. Medical treatment with anti-inflammatories, antimicrobials, and/or antifungals may be successful in some cases, but many of these disorders necessitate surgical intervention. Direct surgical approaches to the guttural pouch are difficult because of their complex anatomy and relationship with important structures, thus precipitating a move toward minimally invasive procedures when possible.

Infections of the Head and Ocular Structures in the Horse

Infectious conditions of the equine head are commonly encountered in clinical practice. Pathogenic bacterial, viral, and fungal organisms may localize in the extensive nasal passages, paranasal sinuses, and guttural pouches, creating a range of clinical signs and conditions that can be severe enough to lead to unexpected fatality. Renewed interest in equine dentistry has led to a greater recognition of dental disease that is associated with infection. This article focuses on bacterial and fungal infections of the main anatomic regions of the equine head, where advances in diagnosis and management have been made or consolidated in recent years. It also addresses recent advances made in the area of infectious equine corneal disease, including bacterial, viral, and fungal etiologies. Recent developments in equine recurrent uveitis as it relates to infectious diseases and ocular manifestations of systemic disease are also discussed.

Laser Fenestration of the Mesial Septum for Treatment of Guttural Pouch Chondroids in a Pony

OBJECTIVE

To describe removal of guttural pouch chondroids through a laser fenestrated mesial septum in a pony with an obstructed pharyngeal ostium of the left guttural pouch.

STUDY DESIGN

Case report.

ANIMALS

Pony.

METHODS

Transendoscopic laser neodymium:yttrium aluminum garnet (Nd:YAG) fenestration of the mesial guttural pouch septum was made by contact method (bare fiber, 15-25 W, exposure time 4 seconds). Dissected tissue was removed by transendoscopic monopolar electrosurgery (loop electrode, cutting blade) and multiple chondroids of varying size were removed from the left guttural pouch through the fenestration.

RESULTS

After removing all chondroids and repeated flushing of the left guttural pouch via the right side, inflammation of the guttural pouch membranes decreased remarkably. The pony was discharged with instructions for transendoscopic lavage once weekly and was reevaluated at 2 months. A permanent septal fenestration was observed and the pony was free of abnormal clinical signs and being used for carriage driving competitions.

CONCLUSION

Nd:YAG laser fenestration of the mesial septum is an approach for access to guttural pouch chondroids.

CLINICAL RELEVANCE

When guttural pouch empyema and/or chondroids is associated with adhesion of the pharyngeal ostium, laser fenestration of the mesial septum from the opposite guttural pouch should be considered as an alternative approach for access, rather than classic external surgical approaches.

Retrospective analysis of 50 cases of guttural pouch tmpany in foals

Between 1994 and 2001, guttural pouch tympany was diagnosed in 51 foals; there were approximately three times as many fillies as colts, of Arabian, different German warmblood breeds and Western horse breeds. There were significantly more Arabian and paint horse foals than expected in comparison with the breed distribution of the foals hospitalised at the Clinic for Horses. The foals' breed and sex did not influence the age of onset, the type and severity of the clinical signs or the recurrence rate. A surgical laser technique was used on 50 of the foals; in 35 cases only one surgical treatment was necessary, in seven cases a second operation was required during the foal's initial period of hospitalisation, and in eight cases a second operation was performed during a second period of hospitalisation. Long-term follow-up information was obtained for 44 of the 50 treated horses; 24 of them were under two years of age and 20 were over two years of age. In six horses, no follow-up information was available. Four horses were euthanased for reasons unrelated to the condition or its treatment. The horses over two years of age were in training or were being used for competitions in dressage or jumping or for breeding purposes, and in only one of them was an adventitious respiratory noise reported. All the horses up to two years of age were reported to be healthy.

Fistulation of the auditory tube diverticulum (guttural pouch) with a neodymium:yttrium-aluminum-garnet laser for treatment of chronic empyema in two horses

Two horses with chronic empyema of the auditory tube diverticulum (guttural pouch) were refractory to medical treatment; empyema was bilateral in 1 horse and unilateral in the other. Both horses were treated by fistulation of the cartilage of the pharyngeal orifice by use of a neodymium:yttrium-aluminum-garnet laser in a noncontact manner. To maintain patency of the fistulae, indwelling catheters were placed into the openings created by the laser. For both horses, long-term follow-up did not reveal complications, and both owners were satisfied with results of the procedure. The authors recommend this procedure for horses that are unresponsive to medical treatment for chronic guttural pouch empyema.

History, Instrumentation, and Techniques of Flexible Endoscopic Laser Surgery in Horses

There are clearly a number of applications for which flexible endoscopic laser surgery has become the state of the art in equine surgery, and the Nd:YAG laser seems to be the most versatile instrument for this type of surgery. Nevertheless, it is critical to understand the advantages and disadvantages of each laser technique. For example, the Nd:YAG laser used in a noncontact fashion seems to be superior when ablation of tissue is required such as treatment of upper airway masses. Conversely, contact Nd:YAG laser techniques have proven themselves to be superior when more precise cutting is advantageous such as treatment of epiglottic entrapment. Ultimately, it seems that a range of lasers is necessary to ensure selection of the most appropriate technique, adding significantly to the expense of equipment but improving the outcome for a range of equine diseases.

Instrumentation and techniques in transendoscopic upper respiratory tract laser surgery

Transendoscopic laser surgery provides equine surgeons with a safe, reliable, and minimally invasive method of performing many surgical procedures in the upper respiratory tract. Although the Nd:YAG laser has proven efficacy, other newer lasers such as the diode and holmium: YAG lasers may prove to be useful tools for equine upper respiratory tract surgery. Long grasping forceps and a high quality fiberoptic or video endoscope are critical components necessary for performing transendoscopic laser surgery. For many of the most common upper respiratory tract abnormalities, a laryngotomy can be eliminated, morbidity is minimal, the horse can often return to normal exercise in approximately 7 to 14 days, and trainer and owner acceptance is excellent. Transendoscopic laser surgery is most likely to be cost effective in large referral practices or in a university setting.