Lumbar hemilaminectomy for treatment of diskospondylitis in an aardvark (Orycteropus afer).

CASE DESCRIPTION A 17-year-old sexually intact male aardvark (Orycteropus afer) was evaluated because of hind limb proprioception deficits and ataxia. CLINICAL FINDINGS Results of examination and CT suggested a diagnosis of intervertebral disk disease and diskospondylitis at the L2-3 intervertebral space. Magnetic resonance imaging of the vertebral column also indicated intervertebral disk rupture with spinal cord compression and inflammation of the adjacent epaxial musculature TREATMENT AND OUTCOME Hemilaminectomy was performed according to the technique described for dogs. Anatomic variations encountered intraoperatively limited the ability to completely remove the affected disk material; however, adequate decompression of the spinal cord was achieved. Microbial culture and susceptibility testing of surgical biopsy specimens yielded a multidrug-resistant Enterococcus faecalis that was treated with a 10-week course of linezolid. Intensive postoperative care required constant rate infusions for adequate sedation, analgesia, and antimicrobial treatment. Dehiscence of the surgical site occurred 3 weeks after surgery and was treated with negative pressure wound therapy. Physical rehabilitation initiated 5 days after surgery progressed from passive range of motion to the use of an underwater treadmill. Despite initial improvement, acute deterioration occurred 5.5 months after surgery. Repeated CT revealed progression of diskospondylitis, which prompted euthanasia. CLINICAL RELEVANCE Postoperative hind limb paresis and paralysis in this species presented considerable challenges for care and rehabilitation. Patient demeanor, size, and anatomy required development of custom mechanical devices. Despite the inability to eliminate the multidrug-resistant bacterial osteomyelitis that resulted in the death of this aardvark, information gained may benefit treatment of subsequent patients.

Occurrence of vertebral osteophytosis in a museum sample of white-beaked dolphins (Lagenorhynchus albirostris) from Danish waters.

The occurrence of pathologic new bone formation in the vertebral column was studied in 46 skeletons of the white-beaked dolphin (Lagenorhynchus albirostris) stranded in Denmark between 1903 and 2002 and held in the collections of the Zoological Museum, University of Copenhagen. New bone formation was evident in 18 (72%) of 25 physically mature specimens and in one of 21 physically immature specimens. This pattern of occurrence is consistent with spondylosis deformans, which is caused by degeneration of the intervertebral disk. In general, females seemed to be more susceptible, exhibiting a higher number of affected vertebrae and more severe cases. Lesions were predominantly detected in the lumbar and cranial caudal vertebra. Data on blubber thickness were available for part of the sample; one of the most heavily afflicted specimens had the thickest recorded blubber, indicating that secondary bone formation leading to blocks of fused vertebrae had not necessarily impaired the body condition of afflicted specimens. However, age determinations conducted on the sample revealed that none of the most severe cases occurred among the oldest animals, implying that these severe cases may cause premature fatality.

Spondylitic changes in long-finned pilot whales (Globicephala melas) stranded on Cape Cod, Massachusetts, USA, between 1982 and 2000.

The primary bone pathology diagnoses recognized in cetacea are osteomyelitis and spondylosis deformans. In this study, we determined the prevalence, type, and severity of vertebral pathology in 52 pilot whales, a mass stranding species that stranded on Cape Cod, Massachusetts, between 1982 and 2000. Eleven whales (21%) had hyperostosis and ossification of tendon insertion points on and between vertebrae, chevron bones, and costovertebral joints, with multiple fused blocks of vertebrae. These lesions are typical of a group of interrelated diseases described in humans as spondyloarthropathies, specifically ankylosing spondylitis, which has not been fully described in cetacea. In severe cases, ankylosing spondylitis in humans can inhibit mobility. If the lesions described here negatively affect the overall health of the whale, these lesions may be a contributing factor in stranding of this highly sociable species.

Skeletal survey of Cayo Santiago rhesus macaques: osteoarthritis and articular plate excrescences.

OBJECTIVES: This study was performed to complement studies on spondyloarthropathy in rhesus macaques by quantifying and characterizing another major form of arthritis and contrasting it with osteoarthritis. METHODS: Skeletons of 269 macaques of known age and troop affiliation from the free-ranging Cayo Santiago colony (Caribbean Primate Research Center) were macroscopically surveyed for the presence of articular changes of osteoarthritis, articular plate excrescences, and calcifications that project back over the joint surface in all diarthrodial joints. Statistical tests were used to establish the independence of pathological conditions, age, gender, troop membership, and specific joint involvement. RESULTS: Subchondral articular surface excrescences or calcific plate-like articular surface overgrowth were noted in 17% and osteoarthritis in 18% of Cayo Santiago macaques. Distribution of joint involvement and sex ratio (1:1) of the former condition were independent of either troop membership or the distribution of osteoarthritis. CONCLUSION: Three major forms of arthritis are common in rhesus macaques: osteoarthritis, spondyloarthropathy, and a category that might be referred to as apical plate excrescences (APE). The latter is very different from spondyloarthropathy, rheumatoid arthritis, osteoarthritis, gout, and infectious arthritis. It is quite similar to what in the past has been referred to as the radiographic form of calcium pyrophosphate deposition disease (CPPD) in humans. A new name has not been offered for the identification/categorization of this phenomenon in dry bone. Its occurrence in rhesus macaques appears to present a natural model for characterization of genetic, immunologic, and environmental aspects of this phenomenon. The acronym APE is offered for consideration in naming this category of arthritis in skeletal material.

Association between the bovine major histocompatibility complex and chronic posterior spinal paresis--a form of ankylosing spondylitis--in Holstein bulls.

A highly significant association was found between the bovine MHC class I antigen BoLA-A8 and a form of vertebral osteophytosis/ankylosing spondylitis known as chronic posterior spinal paresis (PSP) in Holstein bulls (P < 0.001). In a population study, restricted to unrelated bulls, BoLA-A8 was significantly associated with PSP (P = 0.0015) with a relative risk of 34.6. In a family study, one PSP bull, BoLA A8/A20, sired 13 offspring. BoLA-A8 was significantly associated with PSP (P = 0.0008). All five PSP sons inherited the A8 allele and the eight healthy sons each inherited the A20 allele. In three other families a complete association of BoLA-A8 and PSP was observed. Lod score analysis, using all available families, indicated a significant linkage between BoLA and PSP (lod score = 6.9). Based on clinical observation, pathology, age/sex predilection, and a strong association with a class I MHC molecule, this inflammatory disease appears analogous to the human condition known as ankylosing spondylitis.

Ankylosing spondylitis in nonhuman primates: the drill and the siamang.

Nonhuman primates are known to be susceptible to many of the arthritides that afflict humans. Psoriatic like spondyloarthropathies have been reported in gorillas and skeletal hyperostosis in gibbons, rhesus monkeys, and gorillas, and additional cases of both of these conditions occurring in drills (baboons) are noted in this report. One western lowland gorilla and two rhesus monkeys with clinical features consistent with ankylosing spondylitis have been documented previously. Two additional nonhuman primate species with radiographic evidence of ankylosing spondylitis are described. A siamang (gibbon) and two drills (baboons) with the classic radiographic features of ankylosing spondylitis, namely a bamboo spine and sacroiliac joint fusion, are reported.