Research Review June 2003

June brought several papers of interest to orthopaedic surgeons. Bartels et al¹ describe the outcome of prophylactic laser disc ablation in 277 dogs with thoracolumbar disc disease. Dogs that had recovered from an episode of disc disease underwent laser ablation of the nucleus pulposus of discs T10/11 to L3/4. 3.4% of patients had a recurrence of paresis or paralysis. 5 dogs suffered complications, one of which needed a hemilaminectomy. The authors conlude that prophylactic percutaneous laser disc ablation reduced the risk of relapse and has few associated complications.

            Southwood et al² evaluated biochemical markers to reach an early diagnosis of nonunion and infected nonunion fractures in rabbits. A femoral fracture was made in 32 rabbits, and some of the defects were inoculated with Staph aureus. Rabbits with infected fractures had lower serum osteocalcin and bone-specific ALKP and higher serum deoxypyridinoline than non-infected fractures at 4 weeks post fracture. The authors believe that these serum biochemical markers may be useful for clinical evaluation of fracture healing and early diagnosis of osteomyelitis.

            Femoral capital physeal fractures in cats usually arise due to trauma. However, McNicholas et al³ report 26 cases of apparently spontaneous femoral capital fractures. They found that spontaneous fractures tended to occur in heavier neutered males with delayed physeal closure.

            Hypothyroidism is a common but frequently overdiagnosed condition, which has been associated with numerous diseases. Euthyroid sick syndrome causes a decrease in thyroxine in dogs that are not truly hypothyroid which can complicate the clinical picture. Paradis et al⁴ examined the effect of moderate to severe osteoarthritis on canine thyroid function. They compared 31 healthy dogs with 65 dogs with osteoarthritis but no other disease. Basal total T4 was not affected by osteoarthritis. There was a small statistically significant difference between the two groups in free T4 and TSH, but these values were within the reference ranges. The authors therefore concluded that the presence of osteoarthritis does not have to be taken into consideration when evaluation thyroid function in dogs.

            Diseases of the tonsils have been associated with poor performance in racing greyhounds. Montague et al⁵ performed various diagnostic tests to investigate fifteen greyhounds with tonsillar enlargement, coughing and poor racing performance. They found that all of the animals were suffering from respiratory disease, including pneumonia and pulmonary infiltration with eosinophils. Histopathological examination of the enlarged tonsils showed tonsillar lymphoid hyperplasia was more common than tonsillitis. The authors believe that in these cases, respiratory disease rather than tonsillar enlargement was the cause of the dogs’ poor racing performance, and that the link between enlarged tonsils, respiratory disease and racing performance is uncertain.

            Liver disease is commonly diagnosed in the cat, but getting a definitive diagnosis and hence targeting treatment more specifically can be difficult. Ultrasound guided fine needle aspirates of the liver have limited diagnostic value, and more invasive biopsies techniques are often necessary. Savary-Bataille et al⁶ evaluated the technique of percutaneous ultrasound-guided cholecystocentesis in healthy cats. Previously, there has been concern that this procedure may carry an unacceptable risk of bile peritonitis. 12 cats had a 22G 1.5 inch needle introduced into the gall bladder by a right ventral abdominal approach. Complications included a decreased appetite and mild abdominal pain in 4 cats. Post mortem examination of 8 cats after one week showed no gross or histological lesions of abdominal organs. The bile was acellular and bateriologically sterile in 11 cats.  The authors conclude that percutaneous ultrasound-guided cholecystocentesis is safe and technically simple in healthy cats, but its safety and utility in cats with hepato-biliary diseases needs further investigation.

            Powdered pancreatic enzyme supplements are commonly used to treat exocrine pancreatic insufficiency. Rutz et al⁷ report three cases of oral bleeding associated with pancreatic enzyme supplementation. The dogs had previously been diagnosed with exocrine pancreatic insufficiency on the basis of serum TLI activity and the exclusion of other diseases. The three dogs exhibited mild oral bleeding, with no signs of melena or anaemia. A reduction in the dose of the supplement led to a resolution of the bleeding without signs of recurrence of EPI.

            Guptill et al⁸ reviewed the records of over 6000 dogs diagnosed with diabetes mellitus from 1970 to 1999. They found that the number of admissions for diabetes rose from 19 cases per 10,000 in 1970 to 64 cases per 10,000 in 1999, but that the case-fatality rate fell from 36% to 5% in the same time. The highest prevalence was in dogs older than 10 years, small breed dogs and female dogs.

            Finally, Santilli and Gerboni⁹ have reviewed the diagnostic imaging of congenital porto-systemic shunts in dogs and cats. Diagnostic imaging is used to identify the presence of the disease and to guide surgical correction. Operative mesenteric portography is often advocated. However, ultrasonography is considered the method of choice in diagnosis, with colour flow mapping and spectral Doppler techniques increasing the sensitivity. Other non-invasive techniques such as MRI and scintigraphy are also discussed.

1. Bartels et al 2003, JAVMA; 222: 1733

2. Southwood et al 2003, AJVR; 64: 727

3. McNicholas et al., 2002, JAVMA; 221: 1731

4. Paradis et al, 2003, Can Vet J; 44: 407                       

5. Montague et al 2002, Vet Journal; 164: 106

6. Savary-Bataile et al 2003, J Vet Intern Med; 17: 298

7. Rutz et al 2002, JAVMA; 12: 1716

8. Guptill et al, 2003, Vet Journal; 165: 240

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Last modified: December 08, 2003