Surgical treatment of adrenocortical tumors: 21 cases (1990-1996)

Twenty-four adrenocortical tumors were surgically removed from 21 dogs. Histopathological examination confirmed 18 carcinomas and six adenomas. Four dogs died in the perioperative period. Fifteen of the 17 dogs that survived the perioperative period had long-term resolution of their clinical signs. Two dogs with incompletely resected tumors were treated with mitotane to control their clinical signs. Overall median Kaplan-Meier life-table survival for dogs with carcinomas was 778 days (range, one to 1,593 days). Median survival for dogs with adenomas was not reached (range, 11 to 730 days). Histopathological diagnosis, histopathological cellular features, age of the dog, and tumor size were not prognostic of outcome.

Comparison of a continuous suture pattern with a simple interrupted pattern for enteric closure in dogs and cats: 83 cases (1991-1997)

OBJECTIVE

To describe and compare a simple continuous suture pattern with a simple interrupted pattern for enterotomy closure or end-to-end intestinal anastomosis.

DESIGN

Retrospective study.

ANIMALS

58 dogs and 25 cats that underwent enterotomy or intestinal resection and anastomosis.

PROCEDURE

Signalment, surgical procedure, suture pattern, suture material, confirmation of dehiscence, and follow-up were reviewed. Groups were compared by procedure (anastomosis or enterotomy) and by suture pattern.

RESULTS

57 animals underwent continuous closure; 26 had interrupted closure. Only polydioxanone or polypropylene suture materials were used. Overall, 81 (98%) animals had no signs of intestinal dehiscence and survived > 2 weeks. Two animals had confirmed dehiscence after foreign body removal, 1 of 57 (2%) after continuous closure, and 1 of 26 (4%) after interrupted closure.

CLINICAL IMPLICATIONS

The simple continuous closure pattern is an acceptable alternative to simple interrupted closure for small intestinal anastomosis or enterotomy closure.

Surgical treatment of urate calculi in Dalmatians: 38 cases (1980-1995)

OBJECTIVE

To assess clinical signs and response to surgical treatment in Dalmatians with urate urolithiasis.

DESIGN

Retrospective study.

ANIMALS

38 Dalmatians.

PROCEDURE

Medical records from 1980 to 1995 of Dalmatians with urate urolithiasis were reviewed to obtain information on history, results of physical examination, hemogram, biochemical analysis, urinalysis, bacterial culture of urine, diagnostic imaging, analysis of calculi, treatment, and recurrence.

RESULTS

35 (92%) dogs were males. Mean age at admission was 4.9 years. Common clinical findings and initial complaints included dribbling of urine, stranguria, vomiting, tense abdomen with signs of pain, and a large bladder. Hematuria was found in 85% of dogs in which urinalysis was performed. Crystalluria was found in 54% of dogs. Bacteria were isolated from urine from 36% of dogs. Contrast radiography and abdominal ultrasonography were the most sensitive diagnostic tests for uroliths. Dogs that underwent scrotal urethrostomy and cystotomy had the fewest number of recurrent clinical signs that were attributable to urinary calculi. Clinical recurrence rate in dogs on a protein-restricted diet was 27%, compared with that (36%) for dogs on a commercial diet.

CLINICAL IMPLICATIONS

Urate urolithiasis is more commonly recognized in male Dalmatians compared with females. Contrast radiography and ultrasonography appear to be the most useful techniques for detecting urate uroliths. Scrotal urethrostomy and cystotomy was the most effective surgical treatment for preventing recurrence of clinical signs associated with calculi. Complete removal of calculi and protein-restricted diets may have a beneficial effect in reducing recurrence of calculi.

Complications associated with the implantation of polypropylene mesh in dogs and cats: a retrospective study of 21 cases (1984-1996)

Complications associated with implantation of polypropylene mesh in dogs and cats were evaluated retrospectively. Immediate postoperative complications were common (in 10 of 20 cases) but predominantly involved seroma formation which resolved with treatment. The only long-term (i.e., six months or more) complication identified was mass recurrence at the site of tumor resection (in seven of 14 cases). Recurrence was affected by resection size. The average number of ribs resected in cases of thoracic wall neoplasia (with and without mass recurrence) was 1.8 and 3.5, respectively. In this study, implantation of polypropylene mesh facilitated the reconstruction of large tissue defects and was not associated with any serious complications.

Long-term results of surgical correction of persistent right aortic arch in dogs: 25 cases (1980-1995)

OBJECTIVE

To evaluate long-term outcome of dogs with persistent right aortic arch that undergo surgical correction.

DESIGN

Retrospective study.

ANIMALS

25 dogs.

PROCEDURE

Surgical correction consisted of ligation and division of the ligamentum arteriosum through a left fourth intercostal thoracotomy. Long-term (> 6 months after surgery) follow-up information was obtained by means of a telephone survey of owners (22 dogs) and by means of reevaluations by a veterinarian (3).

RESULTS

Median age at the time of surgical treatment was 12 weeks. Short-term (2 to 4 weeks after surgery) follow-up information was available for 14 dogs. Nine no longer regurgitated after eating, and 5 regurgitated infrequently. Follow-up esophagography (median time after surgery, 4 months) was performed in 13 dogs and revealed persistence of megaesophagus in all 13. At the time of long-term follow-up, 23 (92%) dogs no longer regurgitated after eating, and the remaining 2 (8%) had regurgitated less than once per week.

CLINICAL IMPLICATIONS

Contrary to previous reports, surgical correction of persistent right aortic arch resulted in complete alleviation of clinical signs in most dogs and an improvement in signs in the remaining dogs. Persistence of megaesophagus and regurgitation in the early postoperative period did not indicate a poor long-term outcome.

Treatment of recurrent otitis media that developed after total ear canal ablation and lateral bulla osteotomy in dogs: nine cases (1986-1994)

OBJECTIVE

To assess clinical findings and long-term outcome of dogs treated for recurrent middle ear infection that developed after total ear canal ablation and lateral bulla osteotomy.

DESIGN

Retrospective case series.

ANIMALS

Of 94 dogs (142 ears) treated by means of total ear canal ablation and lateral bulla osteotomy for end-stage otitis, 9 developed recurrent middle ear infection.

PROCEDURE

Information regarding treatment and outcome were retrieved from the medical records.

RESULTS

Antibiotic treatment was attempted in 8 dogs, but failed to cure recurrent otitis media in 7 of 8 dogs. Seven dogs were treated by means of exploratory surgery, which consisted of ventral bulla osteotomy and tympanic curettage. One dog was cured, 1 developed another infection and was euthanatized, and the 5 remaining dogs developed another middle ear infection after the first exploratory surgery. Infection resolved after retained epithelium was removed from the tympanic cavity during a second exploratory surgery of the bulla in these 5 dogs.

CLINICAL IMPLICATIONS

Antibiotic treatment rarely is effective for resolving recurrent middle ear infection that develops after total ear canal ablation and lateral bulla osteotomy. Ventral bulla osteotomy and curettage can be a successful method of treatment, provided retained epithelium and debris are completely removed from the ear canal and tympanic cavity.

Factors associated with perioperative mortality in dogs with surgically managed gastric dilatation-volvulus: 137 cases (1988-1993)

OBJECTIVE

To evaluate factors associated with perioperative mortality in dogs with gastric dilatation-volvulus and to determine the influence of treatment differences between university and private specialty practices on outcome.

DESIGN

Retrospective analysis of medical records.

ANIMALS

137 dogs with gastric dilatation-volvulus.

PROCEDURE

Signalment; frequency of preoperative and postoperative treatments and complications; intraoperative findings; surgical technique; and hematologic, serum biochemical, and electrocardiographic results were recorded, evaluated for association with mortality, and compared between institutions.

RESULTS

Mortality did not differ between institutions, and overall mortality was 18% (24/137). Surgical techniques differed between institutions, but were not associated with mortality. Gastric necrosis was associated with significantly higher mortality (46%; 13/28). When partial gastrectomy or splenectomy was performed, mortality (35 and 32% or 8/23 and 10/31, respectively) was significantly increased. Splenectomy was performed in 11 of 23 dogs requiring partial gastrectomy, and when both procedures were performed, mortality (55%; 6/11) was significantly increased. Preoperative cardiac arrhythmias were associated with significantly higher mortality (38%; 6/16). Mortality in dogs > 10 years old was not significantly greater than that in younger dogs.

CLINICAL IMPLICATIONS

Patient management differences between practices did not seem to influence survival in dogs with surgically managed gastric dilatation-volvulus. Signalment, including age, did not influence mortality. Gastric necrosis, gastric resection, splenectomy, and preoperative cardiac arrhythmias were associated with mortality > 30%.

Progressive lymphangiectasis and recurrent chylothorax in a dog after thoracic duct ligation

A 2-year-old Bernese Mountain Dog was examined to determine the cause of bilateral pleural effusion. Torsion was diagnosed, and a lobectomy of a lung lobe was performed. Chylothorax developed 12 days after lung lobectomy. Mesenteric lymphangiography revealed lymphangiectasis Lymphangiography immediately after surgical thoracic duct was completely obstructed, but chylothorax persisted after thoracic duct ligation. Lymphangiography was repeated 50 days after ligation of the thoracic duct and revealed multiple patent thoracic duct branches and progressive lymphangiectasis. A second attempt to ligate the thoracic duct caused the effusion to become serosanguineous. A pleuroperitoneal shunt with a manually operated pump chamber was used to remove the pleural effusion. Chylothorax was again detected 50 weeks after placement of shunt. Mesenteric lymphangiography revealed multiple patent thoracic duct branches and a lymphatic plexus that extended across the thoracic cavity.

Chylothorax in the dog and cat: a review

Chylothorax is a rare but complex disorder in domestic animals. Etiologies include neoplasia, fungal infections, heartworm infestation, cardiac disease, thrombosis of the cranial vena cava, and congenital anomaly of the thoracic duct. Most cases of chylothorax in dogs and cats are idiopathic. Positive contrast lymphangiography on dogs and cats with chylothorax consistently reveals extensive lymphangiectasia of mediastinal and pleural lymphatics. Reported treatment modalities for chylothorax in animals include removal of the etiologic agent, such as a mediastinal tumor, thoracic duct ligation, and implantation of active or passive drainage devices such as a pleuroperitoneal shunt. Thoracic duct ligation has been most successful in our experience, but continued study is needed since treatment failures are common.

Surgical diseases of the nasal cavity and paranasal sinuses

Nasal diseases in small animals range from simple foreign bodies to invasive malignancies, yet the patients may present with identical clinical signs. As is true in many situations in veterinary medicine, one of the first questions a clinician ponders is: does this animal have a good disease or a bad disease? Recent advances in diagnostic methods have improved our ability to answer that question using noninvasive techniques. However, surgical intervention remains a viable option for exploring the nasal cavity and sinuses to establish and possibly treat the cause. If a malignant process is found, owners should be advised that surgery alone is not helpful and that radiation therapy can improve survival. Complications of all treatment options must be thoroughly outlined to owners because they are common.

Evaluation of an autotutorial-simulator program for instruction of hollow organ closure

Forty students were randomly assigned into two study groups (traditional, T; and simulator, S) of 20 students each for a core operative practice laboratory. Students were randomly paired and their group assignment and identity remained anonymous to the evaluators throughout the study. Questionnaires were distributed to students to evaluate prior surgical experience and obtain learning resource use information. Before the evaluation sessions, both groups were given identical learning resource opportunities except students in Group S received hollow organ simulators and practice materials for gastrotomy closure. All students were forewarned that surgical instruction would not be available during the evaluation sessions. In the first live animal evaluation session, all student pairs were videotaped after which stomachs were harvested for gross evaluation of the surgical site. Group T performed an additional gastrotomy for video and gross evaluation 2 weeks later. Questionnaire, and gross and video evaluation results were compared statistically between groups and sessions. The hollow organ model did not suitably simulate live stomach tissue; the material was more fragile and stiff and suture cut-out was a problem even with appropriate suture tension and technique. The model was effective for teaching needle placement, instrument usage, creating proper tissue inversion, and methods to minimize instrument handling of tissue during gastrotomy closure. Prior practice with models did not boost student confidence during their live gastrotomy session. The autotutorials (ATs) were well received by students but did not sufficiently address how to manage mucosal eversion, suture tension, and bleeding encountered during live gastrotomy. AT viewing time positively correlated with mean total video score for Group T during both sessions. None of the students had prior experience performing hollow organ closure and no significant difference in experience level was evident between groups. Mean closure time was not significantly different between groups for session one (Group T, mean, 31.5 minutes, range, 18.4 to 53.4; Group S, mean, 28.2 minutes, range, 16.8 to 36), but was significantly reduced for session two (Group T, mean, 21.3 minutes, range, 13.9 to 31). This AT/simulator program does not significantly influence students' overall gastrotomy closure technique; gross and video evaluation scores were not significantly different between groups. Without instructor supervision, an additional gastrotomy experience did not improve surgical technique appreciably for Group T; however, these students performed the second procedure with more confidence and speed.(ABSTRACT TRUNCATED AT 400 WORDS)

Evaluation of mesenteric lymphangiography and thoracic duct ligation in cats with chylothorax: 19 cases (1987-1992)

Mesenteric lymphangiography and thoracic duct ligation were performed on 19 cats with chylothorax between 1987 to 1992. Chylothorax was diagnosed on the basis of detection of chylomicrons in the pleural effusion or determination of a cholesterol concentration:triglyceride concentration ratio of < 1 in the pleural fluid. Preoperative medical treatment consisted of thoracentesis (19 of 19 cats) and feeding a fat-restricted diet (14 of 19 cats). Positive-contrast mesenteric lymphangiography was performed before thoracic duct ligation to identify an underlying cause for the effusion. Lymphangiectasia was diagnosed by use of radiography in 17 cats, none of which had evidence of a thoracic duct rupture. Thoracic duct ligation was performed via an incision made through the left 10th intercostal space. Lymphangiography was repeated immediately after ligation of the thoracic duct to document occlusion of all branches. Follow-up monitoring was done for 12 to 47 months (median, 28 months) and consisted of physical examination, evaluation for clinical signs related to pleural effusion, and thoracic radiography. Ten of 19 (53%) cats had complete resolution of pleural effusion. Nonchylous effusion, localized in the right hemithorax, was detected in 1 cat 2 months after thoracic duct ligation, but resolved after thoracotomy, breakdown of thoracic adhesions, and expansion of the right cranial lung lobe. Chylous effusion resolved 3 to 7 days (mean, 5.4 days) after surgery in the 10 cats that survived > 12 months after surgery. Four cats died between 2 and 13 days after thoracic duct ligation, but pleural effusion had resolved in 3 of these 4 cats at the time of death.(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroidectomy and parathyroidectomy in the dog and cat

Thyroidectomy has become a fairly common surgical procedure in small animals because of the increasing incidence of thyroid tumors. Surgical removal of the thyroid gland can be routine or quite challenging, depending on the species (cat vs. dog) and the size and aggressiveness of the tumor. Many problems may be encountered with these patients, associated both with the disease and with the surgical treatment. Both thyroid and parathyroid tumors result in many alterations in the animal's homeostasis. These alterations must be recognized by the surgeon to maximize the chance of a successful outcome. This chapter deals with thyroidectomy and parathyroidectomy in dogs and cats. Indications for surgery, pathophysiology of thyroid and parathyroid neoplasia, preoperative care, surgical procedures, and postoperative care and complications will be discussed.

Chylothorax in cats: 37 cases (1969-1989)

Case records of 37 cats with chylothorax examined at 2 institutions were retrospectively evaluated. Dyspnea and coughing were the most common abnormalities noticed by the owners, and most cats were dyspneic on initial examination. There was no statistically significant difference in the gender distribution of cats studied when compared with reference populations; however, purebred cats appeared to be overrepresented in the study population. Four of the cats had unilateral pleural effusion (2 left side, 2 right side) and 9 cats had effusions that were primarily, but not exclusively, on the right side. Surgery was performed on 20 cats. Fifteen cats underwent thoracic duct or cisterna chyli ligation; 20% had complete resolution of pleural fluid. There was no significant difference in the survival rate of cats that underwent thoracic duct ligation and those that were treated by other means. Six cats had mesenteric lymphangiography performed; 2 cats had normal results, and the remainder had various degrees of thoracic lymphangiectasia. Two cats in which pleuroperitoneal shunts were placed and 2 of 3 cats that underwent pleurodesis were euthanatized or died after surgery.

Effects of tetracycline hydrochloride on pleurae in dogs with induced pleural effusion

Pleural effusion was induced in 12 dogs by ligation of the cranial vena cava. Pleurodesis was attempted by injecting a solution of tetracycline hydrochloride into the pleural space of 8 dogs (4 dogs, 25 mg/kg of body weight; 4 dogs, 50 mg/kg) via bilateral thoracostomy tubes. In both groups, tetracycline was diluted in 40 ml of normal saline solution and 10 ml of 1% lidocaine before injection. Half of the solution (25 ml) was instilled in each hemithorax. Four control dogs were treated in the same manner with a solution of normal saline and lidocaine. Daily pleural fluid production was measured after the attempted pleurodesis. Thirty days after administration of the solution, each dog was euthanatized and necropsied. Surface area of pleural adhesions was measured. Tissues from regions of pleural adhesions and areas of parietal and visceral pleura not involved in adhesions were analyzed histologically. Formation of pleural fluid stopped in all but 1 control dog within 48 hours after injection of solution. This dog effused throughout the study. The resolution of effusion was not significantly (P less than 0.05) different between the tetracycline-treated dogs and the control group. Although diffuse pleural adhesions were not induced in any of the dogs, significantly (P less than 0.0027) more surface area of lung was adhered in dogs treated with the higher dose of tetracycline.

Chylothorax associated with dirofilariasis in a cat

A 4-year-old castrated domestic shorthair cat was referred for treatment of chylothorax. Thoracic duct lymphangiography revealed partial obstruction of the cranial vena cava, as evidenced by filling of mediastinal lymphatics with dye instead of all of the dye entering the vena cava. The thoracic duct was ligated via left 10th intercostal space thoracotomy. Immediate postligation lymphangiography revealed successful duct ligation. Results of a serum ELISA for adult heartworm antigen that was performed before surgery were positive. Drug treatment for the heartworm disease was not recommended, because the pleural effusion had ceased (as determined by radiographic examination 3.5 and 9 months after surgery) and the cat was doing well clinically. Sixteen months after surgery, the owner reported that the cat was doing well and did not have signs of respiratory problems.

Results of ligation of patent ductus arteriosus in dogs: 201 cases (1969-1988)

Surgical treatment of 201 dogs with patent ductus arteriosus at the College of Veterinary Medicine, The Ohio State University was evaluated retrospectively to determine risk factors for development of surgical complications. During surgery, 15 dogs (7%) died because of hemorrhage associated with ductus dissection (n = 8), pulmonary edema (n = 4), ventricular fibrillation (n = 1), hemorrhage not associated with ductus dissection (n = 1), and cardiac arrest immediately after ductus ligation (n = 1). An additional 8 dogs (4%) died less than 1 month after surgery (total mortality before, during, and immediately after surgery, 11%). Nineteen dogs (9.5%) developed hemorrhage during surgery. Sixteen dogs developed complications other than hemorrhage (pulmonary edema [n = 4], cardiac arrest [n = 4], iatrogenic lung trauma [n = 3], ventricular fibrillation [n = 2], septicemia [n = 2], and recanalized ductus [n = 2]). Correlation was not found between age, sex, body weight, surgical technique (Jackson method vs standard method of dissection), or surgeon level of training and development of hemorrhage during surgery, other complications, or survival less than 5 days. Positive correlation (P less than 0.05) was found between hemorrhage and death within 5 days after surgery. Positive correlation (P less than 0.05) was also found between other complications and death within 5 days after surgery. Nineteen dogs survived surgery, but later died of unrelated causes (mean life span, 57 months); 63 of the dogs were still alive and doing well as of January 1990 (mean life span, 47 months after surgery). Contrary to previous reports, age, body weight, and surgical technique did not affect results.(ABSTRACT TRUNCATED AT 250 WORDS)

Peritoneal dialysis in dogs and cats: 27 cases (1976-1987)

The records of 25 dogs and 2 cats treated with peritoneal dialysis during an 11-year period were evaluated. The indications for peritoneal dialysis were acute renal failure in 21 animals, chronic renal failure in 5 animals, and azotemia of undetermined cause in 1 animal. Peritoneal dialysis resulted in a significant (P less than 0.05) decrease in serum urea nitrogen concentration in 19 of the dogs and a significant (P less than 0.05) decrease in serum creatinine in 20 dogs. The most common complication of peritoneal dialysis was hypoalbuminemia (11 animals affected). Other common complications were dialysate retention/catheter obstruction (8 animals), peritonitis (6 animals), hypochloremia (6 animals), and subcutaneous leakage of dialysate (6 animals). Twelve dogs and 2 cats died during treatment, 6 dogs were euthanatized, and 1 dog was lost to follow-up evaluation. The remaining 6 dogs survived and were discharged from the hospital after successful peritoneal dialysis. On the basis of the results of this study, the authors concluded that peritoneal dialysis, although associated with a high complication rate, was a successful technique for reducing azotemia in dogs with acute and chronic renal failure. Survival rates were poor because of the severity of the underlying renal diseases.

Results of thoracic duct ligation in dogs with chylothorax

Thoracic duct lymphangiography and ligation were done on 15 dogs with idiopathic chylothorax. Lymphangiography revealed thoracic lymphangiectasia in all dogs; none had a thoracic duct rupture. Lymphangiography immediately after ligation demonstrated missed branches of the thoracic duct in 4 of the 15 dogs. Eleven of the 15 dogs are alive and doing well. Eight of the 11 had no radiographic or clinical signs of pleural effusion (mean follow-up, 31.5 months; range, 4 to 75 months). The other 3 living dogs had persistent effusion; 2 were successfully managed with a pleuroperitoneal shunt (follow-up, 15 months) or pleurodesis (follow-up, 5 months), respectively, and 1 was not treated because the effusion was mild and the dog did not have clinical signs of disease (follow-up, 14 months). Four of the 15 dogs died or were euthanatized because of persistent effusion (mean follow-up, 11.5 months; range, 3 to 24 months). Considering the lack of treatment alternatives for dogs with idiopathic chylothorax, these results support thoracic duct ligation as a treatment method for dogs.

Pulmonary abscess caused by a Mycoplasma sp in a cat

A Mycoplasma sp was isolated from an abscess of the right cranial lung lobe in a 6-year-old Persian cat. The cat responded well to resection of the affected lung lobe and to a 2-week course of tylosin treatment.

Management of intractable pleural effusion in a dog with pleuroperitoneal shunt

Persistent nonchylous pleural effusion followed thoracic duct ligation for chylothorax in a dog. Attempts at tetracycline pleurodesis twice failed to reduce the quantity of pleural effusion. Repeated thoracentesis caused malnutrition and hypoproteinemia. A modified Denver peritoneal-venous shunt was implanted to internally drain the pleural fluid into the peritoneal cavity. Normal body weight and plasma protein concentration were regained in 40 days. Digital compression of the pump chamber alleviated the signs of respiratory compromise, without complication. At 50 weeks post-installation, a proteinaceous clot obstructed the original efferent pump valve, necessitating shunt replacement. Eight weeks after replacement, the dog was asymptomatic.

Aneurysmal bone cyst in a rib of a cat

An aneurysmal bone cyst was identified in the rib of a 3 1/2-year-old domestic shorthair cat. Surgical excision of the cyst, with reconstruction of the thoracic wall, was performed. Though aneurysmal bone cyst is a benign neoplastic condition that may be associated with locally aggressive growth, it does not metastasize. The condition is rare in any species other than human beings, but has been reported in cats, dogs, and horses.

Chylothorax in the dog and cat

The etiology, pathogenesis, and treatment of chylothorax are discussed in this article. A detailed discussion of thoracic duct anatomy, physiology, and methods of lymphangiography is included. The information presented is a review of previous literature, an update on recently completed studies, and speculation about where future research is needed.

Chylothorax associated with congestive cardiomyopathy in a cat

Chylothorax associated with congestive cardiomypathy was diagnosed in a 10-year-old male castrated domestic shorthair cat via analysis of pleural fluid. The triglyceride concentration in the pleural fluid was high (579 mg/dl), compared with that in serum (87 mg/dl), and the fluid cleared with ether. Evidence of atrial and left ventricular enlargement was found via electrocardiography and thoracic radiography. Left-sided cardiac dilatation and reduced systolic motion of the left ventricle were revealed by echocardiography. The cat was treated with digoxin, furosemide, and aspirin. Two months after initiation of treatment, fluid (265 ml) was aspirated from the pleural cavity. Two months after this procedure, the cat was doing well, with minimal pleural fluid production.

Chylothorax in 34 dogs

Thirty-four dogs with chylothorax were studied retrospectively. In 24 dogs, chylothorax appeared to be idiopathic, with only 10 dogs having evidence of neoplasia or trauma. Rupture of the thoracic duct secondary to trauma appeared to be a much less common cause for the development of a chylous pleural effusion than that reported previously. The Afghan Hound was the breed most commonly affected, comprising 37.5% of the dogs in the idiopathic category and 26.5% of all dogs with chylothorax. A clear correlation between the cause of chylothorax and age was not apparent, and gender and neutering appeared to have no relationship to the development of chylothorax in the dog.

Lymphangiographic evaluation of experimentally induced chylothorax after ligation of the cranial vena cava in dogs

Ligation of the cranial vena cava (CrVC) distal to the entrance of the azygous vein resulted in chylothorax in 7 of 10 dogs. Of the remaining 3 dogs, 1 developed a serosanguineous effusion that did not become chylous, and 2 dogs did not develop pleural effusion. In 2 of the 7 dogs developing chylothorax, the pleural effusion became serosanguineous within 2.5 weeks after CrVC ligation. Mesenteric lymphangiography was performed 2 to 6 weeks after ligation of the CrVC. Lymphangiectasia was seen in 4 dogs with chylothorax, but was not seen in the 3 dogs with serosanguineous effusions or the 2 dogs that did not develop effusions. One dog with chylothorax died prior to repeat lymphangiography. Less dye entered the thoracic duct, and alternate lymphaticovenous communications to the caudal vena cava were evident in the dogs without chylothorax. Ligation of the thoracic duct at the lymphaticovenous junction was performed in 3 dogs. These dogs did not develop pleural effusion. Lymphangiography was performed immediately after ligation and indicated filling of abdominal lymphatics but not of the thoracic duct. Lymphangiographic findings 6 weeks after ligation also indicated filling of intestinal lymphatics. Results of the present study indicated that ligation of the CrVC causes chylothorax, and that thoracic lymphangiectasia is a consistent finding in animals with experimental chylothorax. Obstruction of the thoracic duct did not induce lymphangiectasia or chylothorax. Impedence of thoracic duct flow into the CrVC may be a cause of clinical chylothorax in the dog.

Evaluation of cholesterol and triglyceride concentrations in differentiating chylous and nonchylous pleural effusions in dogs and cats

Serum and pleural fluid cholesterol and triglyceride concentrations and cholesterol/triglyceride ratios were determined in 9 dogs and 9 cats with pleural effusion (8 nonchylous, 10 chylous). The pleural fluid triglyceride concentrations were significantly higher (P less than 0.05) and the pleural cholesterol/triglyceride ratios were significantly lower (P less than 0.05) in chylous effusions than in nonchylous effusions in all animals. There were no differences in serum cholesterol and triglyceride concentrations and serum cholesterol/triglyceride ratios for chylous and nonchylous effusions in either species. There also were no differences in pleural fluid cholesterol concentrations between the 2 groups in the dog or cat. It was concluded that determinations of cholesterol/triglyceride ratios may be an accurate method for helping distinguish chylous from nonchylous effusions in dogs and cats.

Mesenteric lymphography and ligation of the thoracic duct in a cat with chylothorax

Mesenteric lymphography was used to identify and ligate the thoracic duct in a 1-year-old Himalayan cat with chylothorax. Lymphography revealed the thoracic duct to be intact; however, multiple dilated lymphatics, indicative of lymphangiectasia were evident in the cranial portion of the thorax. Hemostatic clips were used to ligate the thoracic duct. The effusion stopped, and 9 months after surgery, effusion has not recurred.

Surgical correction of primary pneumothorax in a dog

Surgical repair of primary pneumothorax in a dog was performed by a median sternotomy and partial lung lobectomies using an automatic suturing device. A median sternotomy was performed since the location of the lesion was undetermined preoperatively. The automatic suturing device provided a quick, simple, and secure method of performing the partial lobectomies. Ruptured blebs and subpleural emphysema were present in the excised pulmonary tissue. Mechanical pleurodesis was also performed in an attempt to prevent recurrence. Large-gauge orthopedic wire was used to close the sternotomy in order to minimize postoperative complications. On follow-up evaluation 6 months later, the dog was normal.