Subtotal colectomy and ileocolonic anastomosis in a Vietnamese pot-bellied pig with idiopathic megacolon.

A 7-month-old sexually intact female Vietnamese pot-bellied pig was evaluated because of constipation. On abdominal palpation, a hard tubular structure was palpated in the middle of the abdomen. Abdominal radiography revealed loops of intestine that were markedly distended with ingesta, consistent with obstructive intestinal disease. On exploratory celiotomy, a massively distended cecum and spiral colon were found. A subtotal colectomy, with a side-to-side ileocolonic anastomosis, was performed. The cause of the megacolon was not discovered. The pig did well following surgery and eventually defecated normally following an initial period of diarrhea. To our knowledge, this is the first report of therapeutic removal of a substantial portion of the large intestine in swine. Our decisions concerning the pig of this report were based largely on our knowledge of megacolon in cats. The outcome for this pig indicates that subtotal colectomy along with removal of the cecum and ileocecal valve can be used to successfully treat idiopathic megacolon in Vietnamese pot-bellied pigs.

Complications of balloon catheterization associated with aberrant cerebral arterial anatomy in a horse with guttural pouch mycosis.

A 3-year-old Quarter Horse gelding was treated for left guttural pouch mycosis by ligation and balloon catheterization of the left internal carotid artery. Catheter advancement was shorter (10 cm) than the normally reported distance (13-15 cm), but was observed endoscopically during placement as it coursed within the internal carotid artery through the guttural pouch. The horse developed a persistently abnormal respiratory pattern after catheter placement, failed to gain consciousness, developed pulmonary edema, and died 5.5 hours postoperatively. Postmortem examination revealed an aberrant left internal carotid arterial course with location of the embolectomy catheter at the junction of the basilar and caudal cerebellar arteries. Brainstem neuronal necrosis and alveolar and interstitial pulmonary edema were identified on histological examination. Angiography may be used to identify aberrant branching patterns. Failure to identify and occlude aberrant branches may result in fatal epistaxis and Brainstem lesions.

Surgery of the adnexa.

Review of the functional anatomy of ocular adnexal tissues is followed by presentation of surgical procedures aimed at correcting conditions of the eyelids, conjunctiva, and third eyelids of small animals. Procedures used effectively by the primary author are described in detail including instances where combination procedures may be indicated. Some newer, recently described techniques are also briefly discussed. Illustrations of applied anatomy and multiple surgical techniques are provided by illustrator and coauthor Dr. Gheorghe Constantinescu. References are given to encourage readers to further explore alternative techniques focusing on the surgical correction of adnexal diseases of dogs and cats.

Surgery for cataracts.

The advent of phacoemulsification has substantially improved the success rate of cataract surgery in dogs, whereas the development of artificial lens implantation has equally improved postoperative visual acuity. In this chapter information pertaining to the etiology, diagnosis, and management of canine cataracts is provided for the general practitioner. More detailed information on phacoemulsification and artificial lens implantation is provided for residents in training or practicing ophthalmologists that may be converting from extracapsular extraction.

Permanent urinary diversion in two Vietnamese pot-bellied pigs by extrapelvic urethral or urethropreputial anastomosis.

Permanent urinary diversion was performed in a Vietnamese pot-bellied pig to bypass apparent urethral obstruction at the level of the urethral recess and in a second pig to correct bleeding from perineal urethrostomy. In the first pig, extrapelvic anastomosis of the penile portion of the urethra to the pelvic portion of the urethra was performed. In the second pig, the penis was amputated and the pelvic portion of the urethra was anastomosed to the preputial epithelium, creating a urethropreputial conduit. Postoperatively, positive-contrast radiography demonstrated continuity of the anastomoses, and both pigs were able to urinate normally. The pig with the urethropreputial anastomosis developed hematuria and nocturia that were controlled by continuous administration of antibiotics and resolved following cleansing of the preputial diverticulum 1 year after surgery. Extrapelvic urinary diversion should be considered for permanent resolution of urethral obstruction in Vietnamese pot-bellied pigs; urethral anastomosis is preferable to urethropreputial anastomosis, because of the greater risk of ascending urinary tract infection associated with urethropreputial anastomosis.

Atlantoaxial malformation in a half-Arabian colt.

A 1-year-old half-Arabian colt was referred for evaluation of a cranial cervical abnormality. Physical examination revealed the left wing of the atlas to be more ventral than the right wing. A head tilt, with the pole deviated to the left, was present because of the malpositioned atlas. Neurologic examination identified symmetrical weakness, ataxia, and proprioceptive deficits in all four limbs. Radiographs of the cranial cervical region revealed fusion of the atlas and axis, and deviation of the atlantoaxial joint to the left of the median plane. Euthanasia was elected. Necropsy confirmed the radiographic findings. The atlas was rotated 20 degrees counterclockwise when viewed from the caudal aspect. Multifocal myelomalacia was present in the first and second cervical spinal cord segments. The malformation was believed to be due to a degenerative process or abnormal embryological development.

The anatomy of the visceral and autonomic nervous systems.

The visceral nervous system has several levels of anatomical organization. Individual viscera, including the heart and the intestines, have neural tissue embedded in their walls that is capable, under some circumstances, of a truly autonomic self-regulation of that organ's activity. This self-regulation will not respond to all the varying needs of the organ control, particularly when external or internal changes affect the whole animal. The parasympathetic, sympathetic, and visceral afferent systems and their CNS connections are the next level of reflex neural organization. A greater degree of central regulation is managed at this level. The third level of visceral control is located in the brainstem and includes the hypothalamus, parts of the reticular formation, and cardiorespiratory centers in the medulla. These visceral upper neuron centers exert a high degree of control over the parasympathetic and sympathetic LMN centers of the brainstem and spinal cord. The reticulobulbar and reticulospinal pathways are the means by which the visceral upper motor neurons communicate with the LMN systems. The hypothalamus-hypophyseal system exerts control by releasing hormones to act on distant target organs. The highest level of organization of visceral function takes place in the limbic system. The limbic system is in a position to integrate sensory information originating from both within (interoceptive) and outside (exteroceptive) the animal. Associations are made at this level and with the help of cortical association areas, memory is integrated with these sensations. The limbic system is then able to influence the hypothalamic and medullary centers as well as the somatic motor centers to develop the appropriate responses for the preservation of the animal.