A 3-Dimensional Printed Patient-Specific Surgical Guide to Facilitate Transsphenoidal Hypophysectomy in Dogs.

Objective: Hypophysectomy in dogs is a difficult surgery that requires specific learning and training. We aimed to evaluate the accuracy of a 3-dimensional printed patient-specific surgical guide to facilitate choosing the entry point in the basisphenoid bone before approaching the sella turcica during transsphenoidal hypophysectomy in dogs. Methods: Two canine cadavers and 8 dogs undergoing transsphenoidal hypophysectomy for Cushing's disease treatment, involving design and fabrication of a 3-dimensional printed guide. The ideal entry point in the basisphenoid bone outer cortical layer was determined in each dog pre-operatively; its anatomical location was described with a set of measurements then compared to post-operative computed tomography measures describing the location of the outer cortical window created in the basisphenoid bone. Results: Several guide designs were proposed, and a consensus reached based on surgeons' experience performing hypophysectomy. The device chosen could be applied to the size and shape of skulls encountered in this case series. The pre-planned measurements were comparable to post-operative measurement (there was also no statistical difference), with median of differences <0.1 mm, which we judged as clinically acceptable. Clinical Significance: Hypophysectomy in dogs is a challenging procedure that has a learning curve and needs to be performed by specialist neurosurgeons. We propose that a low-profile 3-dimensional printed surgical guide can aid the specialist neurosurgeon to locate the burring site of the outer cortical layer of the basisphenoid bone at a pre-defined location and with good accuracy. It does not alleviate the need to understand the anatomy of the region and to know how to create a slot within the basisphenoid bone, which remains essential to enter the sella turcica. This device could help specialist veterinary neurosurgeons wishing to be trained to perform hypophysectomy.

Feline Pituitary Adenomas: Correlation of Histologic and Immunohistochemical Characteristics With Clinical Findings and Case Outcome.

Pituitary glands from 141 feline autopsy cases were reviewed histologically. Adenoma and hyperplasia were the most common lesions at 13 cases each. Pituitary adenoma was more likely than hyperplasia to be associated with clinical evidence of endocrinopathy or an intracranial mass (P < .001). A histochemical and immunohistochemical panel was applied to 44 autopsy- or hypophysectomy-derived pituitary adenomas in 43 cats from 2 diagnostic laboratories. Adenomas were differentiated from hyperplasia by the presence of disrupted reticulin fibers. One cat had a double (somatotroph and melanotroph) adenoma. Twenty somatotroph adenomas consisted of periodic acid-Schiff (PAS)-negative acidophils that expressed growth hormone; 16/20 had hypersomatotropism; 17/20 had diabetes mellitus. Eleven melanotroph adenomas consisted of PAS-positive basophils or chromophobes that expressed melanocyte-stimulating and adrenocorticotrophic hormones; 5/11 had hypercortisolism; 6/11 had diabetes mellitus. Eleven gonadotroph adenomas consisted of PAS-negative chromophobes that expressed follicle-stimulating and/or luteinizing hormones. Two thyrotroph adenomas consisted of PAS-negative basophils or chromophobes that expressed thyroid-stimulating hormone. Pituitary-dependent disease was not recognized in cats with gonadotroph or thyrotroph adenomas. The Ki-67 proliferation index in hypophysectomy specimens was lower in somatotroph than in melanotroph adenomas. Fourteen cats with hypophysectomy-treated somatotroph or melanotroph adenoma had an 899-day median survival time versus 173 days in 17 nonsurgical cases. After adjusting for age, adenoma size and type, hypophysectomized cats had an overall better survival time than nonsurgical cases (P = .029). The study results underscore the value of hypophysectomy and trophic hormone immunohistochemistry in the treatment and classification of feline pituitary adenomas.

Effect of Targeted Pulsed Electromagnetic Field Therapy on Canine Postoperative Hemilaminectomy: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial.

Intervertebral disc disease is one of the leading causes of paralysis in dogs. Pulsed electromagnetic field (PEMF) therapy has been advocated for improving wound healing and pain reduction; however, robust clinical trials are lacking. The present prospective, double-blind, placebo-controlled trial evaluated targeted PEMF therapy administered to 53 client-owned dogs who underwent hemilaminectomy for naturally occurring disk extrusion intervertebral disc disease. The dogs were randomized to receive either targeted PEMF (n = 27) or placebo treatment (n = 28). Wound healing, evaluated by visual analog score and wound evaluation scale, was significantly improved at 6 wk postoperatively in the treatment compared with the control group (P = .010 and .023, respectively). Pain medications were administered less frequently in dogs receiving PEMF treatment during the 7 day postoperative period compared with the control treatment group (P = .010) with codeine administered 1.8 times more frequently in the control group. No untoward effects were recorded in either treatment group. More frequent evaluation of outcome measures with larger patient numbers, as well as histologic samples, may be useful in future studies. Dogs receiving PEMF therapy following postoperative hemilaminectomy demonstrated improved wound scores at 6 wk and reduced mean number of owner-administered pain medications compared with the control group therapy.

Metabolic Encephalopathy and Lipid Storage Myopathy Associated with a Presumptive Mitochondrial Fatty Acid Oxidation Defect in a Dog.

A 1-year-old spayed female Shih Tzu presented for episodic abnormalities of posture and mentation. Neurological examination was consistent with a bilaterally symmetric multifocal encephalopathy. The dog had a waxing-and-waning hyperlactemia and hypoglycemia. Magnetic resonance imaging revealed bilaterally symmetric cavitated lesions of the caudate nuclei with less severe abnormalities in the cerebellar nuclei. Empirical therapy was unsuccessful, and the patient was euthanized. Post-mortem histopathology revealed bilaterally symmetric necrotic lesions of the caudate and cerebellar nuclei and multi-organ lipid accumulation, including a lipid storage myopathy. Malonic aciduria and ketonuria were found on urinary organic acid screen. Plasma acylcarnitine analysis suggested a fatty acid oxidation defect. Fatty acid oxidation disorders are inborn errors of metabolism documented in humans, but poorly described in dogs. Although neurological signs have been described in humans with this group of diseases, descriptions of advanced imaging, and histopathology are severely lacking. This report suggests that abnormalities of fatty acid metabolism may cause severe, bilateral gray matter necrosis, and lipid accumulation in multiple organs including the skeletal muscles, liver, and kidneys. Veterinarians should be aware that fatty acid oxidation disorders, although potentially fatal, may be treatable. A timely definitive diagnosis is essential in guiding therapy.

Canine struvite urolithiasis.

Struvite calculi, composed of magnesium ammonium phosphate, have existed for thousands of years in human medicine and are a leading cause of calculi in companion animals. Struvite stones have also been called urease, infection-induced, phosphatic, and triple phosphate stones. They are the most common uroliths in dogs, in which most cases of struvite urolithiasis are associated with infection. Management of struvite urolithiasis requires a multimodal approach that addresses the presence of the urolith(s) and associated infection while identifying risk factors that predispose to the development of infection.

Methods of urolith removal.

Multiple techniques exist to remove uroliths from each section of the urinary tract. Minimally invasive methods for removing lower urinary tract stones include voiding urohydropropulsion, retrograde urohydropropulsion followed by dissolution or removal, catheter retrieval, cystoscopic removal, and cystoscopy-assisted laser lithotripsy and surgery. Laparoscopic cystotomy is less invasive than surgical cystotomy. Extracorporeal shock wave lithotripsy can be used for nephroliths and ureteroliths. Nephrotomy, pyelotomy, or urethrotomy may be recommended in certain situations. This article discusses each technique and gives guidance for selecting the most appropriate technique for an individual patient.

Urate urolithiasis.

Urate uroliths belong to the purine family of uroliths and are the third most common urolith type in dogs and cats. In dalmatians, an autosomal recessive trait is responsible for hyperuricosuria and a predisposition to urate urolithiasis. In other dog breeds and in cats, urate uroliths are predominantly associated with liver disease, specifically portosystemic vascular anomalies. Idiopathic urate uroliths may occur in animals without liver disease. Ammonium urate uroliths are most common. Urate uroliths are amenable to medical dissolution. This article reviews the pathogenesis and management of urate urolithiasis.

Calcium oxalate urolithiasis.

Calcium oxalate (CaOx) uroliths are one of the most common urolith types in dogs, cats, and humans. Many factors predispose animals to CaOx uroliths, including breed, old age, obesity, male sex, being neutered, and certain diseases. Because there are no effective strategies for medical dissolution of these uroliths, management should focus on physical removal (by surgical or nonsurgical methods) and prevention, especially in patients with recurring uroliths, high-risk breeds, and animals with predisposing diseases. Prevention focuses on diet modification, primarily to increase water intake, and the appropriate use or avoidance of specific medications.

Feline struvite urolithiasis.

Feline urolithiasis represents 15% of all cases of nonobstructive lower urinary tract disease in cats. Approximately 50% of feline uroliths are composed of struvite. Struvite urolithiasis commonly recurs, but optimal management may decrease its frequency. The pathophysiology and management of struvite urolithiasis are different in cats and dogs. This article focuses on struvite urolithiasis in cats, highlighting important aspects of pathophysiology, treatment, and prevention.

Diagnosis of urolithiasis.

Diagnostic imaging is usually required to determine the presence of urolithiasis. Double-contrast cystography is more accurate than survey radiography and approximately as accurate as ultrasonography. Knowledge of the mineral composition of calculi helps direct appropriate management of urolithiasis, and signalment can help predict composition with about 70% accuracy. In cats, about half of cystic calculi are struvite and half are calcium oxalate; most nephroliths and ureteroliths are calcium oxalate. In female dogs, struvite uroliths are the predominant type found in the bladder. In male dogs, breed plays a strong role in prediction of bladder urolith type. It is difficult to predict the composition of nephroliths and ureteroliths based on signalment alone in dogs. Urinalysis and imaging findings can help in predicting urolith composition, although chemical analysis is necessary for definitive diagnosis.