Incidence of intervertebral disk degeneration-related diseases and associated mortality rates in dogs.

OBJECTIVE: To determine the incidence and distribution of intervertebral disk (IVD) degeneration-related diseases in a large population of dogs of various breeds, ages, and sexes and to determine mortality rates among dogs with these diseases. DESIGN: Epidemiological study. SAMPLE: Insurance data for dogs with veterinary health-care and life insurance coverage (n = 665,249 and 552,120, respectively). PROCEDURES: Insurance claim records of 1 company in Sweden were searched to identify dogs with IVD degeneration-related diseases; incidence and mortality rates were determined for affected dogs < 12 years old and < 10 years old, respectively. Only the first paid IVD degeneration-related claim for a dog was included in incidence rate calculations. RESULTS: The incidence rate of IVD degeneration-related diseases was 27.8 (95% confidence interval [CI], 27.2 to 28.4) occurrences/10,000 dog-years at risk (DYAR), indicating that approximately 0.3% of dogs/y in this population were affected. Miniature Dachshund was the most highly represented breed, followed by Standard Dachshund and Doberman Pinscher (237.1 [95% CI, 212.9 to 261.4], 141.5 [95% CI, 135.5 to 147.4], and 88.6 [95% CI, 72.1 to 105.2] occurrences/10,000 DYAR, respectively). The incidence rate of IVD degeneration-related disease was greater in male than in female dogs and increased with age. Overall mortality rate attributed to IVD degeneration-related diseases was 9.4 (95% CI, 8.9 to 9.8) deaths/10,000 DYAR and was greater in males than in females. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in incidence rates among various breeds suggested a genetic involvement. Knowledge of the distribution of IVD degeneration-related diseases among dogs of various breeds and ages may facilitate early diagnosis and preemptive treatments in patients at risk for developing these diseases.

Biomechanical assessment of the effects of decompressive surgery in non-chondrodystrophic and chondrodystrophic canine multisegmented lumbar spines.

PURPOSE: Dogs are often used as an animal model in spinal research, but consideration should be given to the breed used as chondrodystrophic (CD) dog breeds always develop IVD degeneration at an early age, whereas non-chondrodystrophic (NCD) dog breeds may develop IVD degeneration, but only later in life. The aim of this study was to provide a mechanical characterization of the NCD [non-degenerated intervertebral discs (IVDs), rich in notochordal cells] and CD (degenerated IVDs, rich in chondrocyte-like cells) canine spine before and after decompressive surgery (nucleotomy). METHODS: The biomechanical properties of multisegmented lumbar spine specimens (T13-L5 and L5-Cd1) from 2-year-old NCD dogs (healthy) and CD dogs (early degeneration) were investigated in flexion/extension (FE), lateral bending (LB), and axial rotation (AR), in the native state and after nucleotomy of L2-L3 or dorsal laminectomy and nucleotomy of L7-S1. The range of motion (ROM), neutral zone (NZ), and NZ stiffness (NZS) of L1-L2, L2-L3, L6-L7, and L7-S1 were calculated. RESULTS: In native spines in both dog groups, the greatest mobility in FE was found at L7-S1, and the greatest mobility in LB at L2-L3. Surgery significantly increased the ROM and NZ, and significantly decreased the NZS in FE, LB, and AR in both breed groups. However, surgery at L2-L3 resulted in a significantly larger increase in NZ and decrease in NZS in the CD spines compared with the NCD spines, whereas surgery at L7-S1 induced a significantly larger increase in ROM and decrease in NZS in the NCD spines compared with the CD spines. CONCLUSIONS: Spinal biomechanics significantly differ between NCD and CD dogs and researchers should consider this aspect when using the dog as a model for spinal research.

Assessment of decompressive surgery in dogs with degenerative lumbosacral stenosis using force plate analysis and questionnaires.

OBJECTIVE: To evaluate the long-term outcome after decompressive surgery in dogs with degenerative lumbosacral stenosis (DLS), using force plate analysis (FPA) and owner questionnaires. STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs with DLS (n=31) and 24 clinically normal Labrador Retrievers. METHODS: FPA was performed before surgery (31 dogs) and at 3 days, 6 weeks, 6 months (each, 31 dogs) and >or=1.5 years (12 dogs) after surgery. Peak vertical forces (Fz(+)), braking (Fy(+)), and propulsive forces (Fy(-)), and the corresponding impulses were determined. Questionnaires were completed by the owners before and at 6 months and >or=1.5 years after surgery. RESULTS: Fy(-) of the pelvic limbs and the ratio pelvic/thoracic of Fy(-) (P/TFy(-)) were significantly smaller in dogs with DLS than controls. Fy(-) and P/TFy(-) decreased significantly 3 days after surgery, and increased during 6 months follow-up, but with long-term follow-up the values remained the same and were smaller than controls. From questionnaires there was a significant improvement after surgery compared with function before surgery. Most owners were satisfied with outcome after surgery. CONCLUSIONS: Propulsive forces of the pelvic limbs in dogs with DLS are impaired and are partially restored by decompressive surgery. CLINICAL RELEVANCE: Owner's questionnaires illustrate that decompressive surgery restores function as perceived by owners whereas FPA continues to show impaired propulsive forces for the pelvic limbs.

Assessment of collagen genes involved in fragmented medial coronoid process development in Labrador Retrievers as determined by affected sibling-pair analysis.

OBJECTIVE: To evaluate the involvement of various collagen genes in the development of fragmented medial coronoid process (FCP) in Labrador Retrievers. SAMPLE POPULATION: 93 dogs originating from 13 litters were used in the study; FCP was diagnosed in 35 dogs, and each affected dog had at least 1 sibling that was also affected. Twelve dams and sires were included in the analysis. All dogs were purebred Labrador Retrievers except for 2 litters (offspring of a female Golden Retriever-Labrador Retriever mixed-breed dog). PROCEDURES: For each dog, DNA was isolated from blood samples. Polymorphic microsatellite markers adjacent to 14 candidate genes (ie, COL1A1, COL1A2, COL2A1, COL3A1, COL5A1, COL5A2, COL6A3, COL9A1, COL9A2, COL9A3, COL10A1, COL11A1, COL11A2, and COL24A1) were analyzed by use of PCR assays; genotypes were determined via automated detection of DNA products. The level of allele sharing between pairs of affected siblings was assessed. RESULTS: Among the 93 dogs, allele sharing of the 14 collagen genes was determined as follows: COL1A1, 45%; COL1A2, 47%; COL2A1, 37%; COL3A1, 32%; COL5A1, 43%; COL5A2, 32%; COL6A3, 36%; COL9A1, 45%; COL9A2, 49%; COL9A3, 38%; COL10A1, 46%; COL11A1, 52%; COL11A2, 47%; and COL24A1, 47%. CONCLUSIONS AND CLINICAL RELEVANCE: Because siblings share 50% of their genome at random, the fact that the percentages of allele sharing among the analyzed collagen genes were not significantly > 50% indicates that these genes are not determinant candidates for FCP in Labrador Retrievers. The gene for the vitamin D receptor could also be excluded because of its proximity to COL2A1.