Sa’ad, M. Y. ISMAIL, Christina M. MURRAY, Mark A. STEVENSON, Hung-Hsun YEN, Helen, M. S. DAVIES

Variations in the median sacral crest and angulation of the first sacral spinous process associated with sacrocaudal fusion in greyhounds

The current study aimed to investigate the association between the morphology of the median sacral crest, variation in the angle of the spinous process of the first sacral vertebra, and the occurrence of sacrocaudal fusion in greyhounds. In this study, 167 sacra from cadavers of greyhounds (previously euthanized for reasons unrelated to this study) were collected, classified into standard and fuses sacra (based on the number of fused vertebrae and type of fusion), and then classified based on the morphology of the median sacral crest into three different types: type F (full crest), type N (when the median sacral crest is incomplete, and type R (when the median sacral crest is present but it was short or reduced). Among the 167 sacra, 91 sacra were used to measure the angle of the spinous process of the first sacral vertebrae (1st SPA). Each of the sacra was digitally photographed using a Nikon D3100 digital camera (Tokyo, Japan) in which the camera was positioned laterally with the lens parallel to the central part of the lateral aspect of the sacrum and on a flat surface of the laboratory bench. Image-Pro Express Version 5.0 imaging software (Media Cybernetics, Silver Spring, Maryland) was used to draw and measure the angles. The angle of the 1st SPA was defined as the angle formed dorsally at the intersection of two lines. The first line was drawn to represent the cranial ridge of the spinous process of the 1st SPA, and the second line was drawn across the most dorsal surface points of the spinous processes of the 1st (S1) and 3rd (S3) sacral vertebrae. Significant (p < 0.001) morphological differences (F, R, N) were found in the median sacral crest, and the prevalence of median sacral crest type R in standard sacra was 35.1% compared to 10% in fused sacra, type F was 41.2% in standard sacra and 10% in fused sacra, and type N was 23.7% in standard sacra and 80% in fused sacra. The angle 1st SPA with median sacral type N was statistically significantly less (more upright) than those in sacra with median sacral type F (P < 0.042). Differences have been found in the median sacral crest and angulation of the spinous process of S1 vertebra in sacra with different types of median sacral crest.

PDF

___

1. König, HE, Liebich HG. Veterinary anatomy of domestic mammals: textbook and colour atlas. Schattauer Verlag 2013.
2. Slijper E. Comparative biologic anatomical investigations on the vertebral column and spinal musculature of mammals. Tweede Sectie 1946; 17 (5): 1-128.
3. Eisenstein, S. The morphometry and pathological anatomy of the lumbar spine in South African negroes and caucasoids with specific reference to spinal stenosis. The Journal of Bone and Joint Surgery. British volume 1977; 59 (2): 173-180. doi: 10.1302/0301- 620X.59B2.873978
4. Simoens P, Vos ND, Lauwers H, Nicaise M. Numerical vertebral variations and transitional vertebrae in the goat. Anatomia, Histologia, Embryologia 1983; 12 (2): 97-103. doi: 10.1111/j.1439- 0264.1983.tb01006.x
5. Struthers, J. Variations of the vertebrae and ribs in man. Journal of Anatomy and Physiology 1874; 9 (Pt 1): 17.
6. Evans HE, De Lahunta A. Miller’s anatomy of the dog. Elsevier Health Sciences 2013.
7. Levine JM, Levine GJ, Hoffman AG, Mez J, Bratton GR. Comparative anatomy of the horse, ox, and dog: the vertebral column and peripheral nerves. Equine Continuing Education for the Practicing Veterinarian 2007; 2: 279-292.
8. Sisson S, Grossman JD, Getty R. Sisson and Grossman’s the Anatomy of the Domestic Animals. Saunders; 1975.
9. Oheida AH, Philip C J, Yen HH, Davies HM. Observations of sacrocauclal fusion in greyhounds and other dogs. Veterinary and Comparative Orthopaedics and Traumatology 2016; 29 (1): 61- 67. doi.org/ 10.3415/VCOT-15-04-0069.
10. Lawrence IK, Lin. A concordance correlation coefficient to evaluate reproducibility. Biometrics 1989; 255-268. doi. org/10.2307/2532051
11. Steichen TJ, Cox NJ. A note on the concordance correlation coefficient. The Stata Journal 2002; 2 (2): 183-189. doi. org/10.1177/1536867X0200200206
12. Landis JR. GG. Koch. The measurement of observer agreement for categorical data. Biometrics 1977; 159-174. doi: 1 0.2307/2529310
13. Frost H. Bone dynamics in metabolic bone disease. Journal of Bone and Joint Surgery 1966; 48 (6): 1192-1203
14. Lanyon L. Functional strain as a determinant for bone remodeling. Calcified Tissue International 1984; 36 (1): S56-S61.
15. Rubin CT, Lanyon LE. Regulation of bone mass by mechanical strain magnitude. Calcified Tissue International 1985; 37 (4): 411-417.
16. Khan K, McKay H, Kannus P, Wark J. Bailey, D., and Bennell, K, Physical activity and bone health: Human Kinetics. Champaign IL 2001.
17. Santinelli I, Beccati F, Arcelli R, Pepe M. Anatomical variation of the spinous and transverse processes in the caudal cervical vertebrae and the first thoracic vertebra in horses. Equine veterinary journal 2016; 48 (1): 45-49. doi: 10.1111/evj.12397
18. Beaubien BP, Freeman AL, Buttermann G.R. Morphologic and biomechanical comparison of spinous processes and ligaments from scoliotic and kyphotic patients. Journal of Biomechanics, 2016; 49 (2): 216-221. doi: 10.1016/j.jbiomech.2015.12.012
19. Panjabi MM, White A. Clinical biomechanics of the spine; 1990.
20. Panjabi MM. The stabilizing system of the spine. Part I. Function, dysfunction, adaptation, and enhancement. Journal of Spinal Disorders, 1992; 5: 383-383.
21. Bernasconi C, Grundmann S, Montavon P. Simple techniques for the internal stabilisation of fractures and luxations in the sacrococcygeal region in cats and dogs. Schweiz Arch Tierheilk 2001; 143: 296-303.
22. Feeney D, Oliver J. Blunt spinal trauma in the dog and cat: insight into radiographic lesions. Journal American Animal Hospital Association 1980.
23. Wang T, Fielding LC, Parikh A, Kothari M, Alamin T. Sacral spinous processes: a morphologic classification and biomechanical characterization of strength. The Spine Journal 2015; 15 (12): 2544-2551. doi: 10.1016/j.spinee.2015.08.058
24. Lazennec JY, Clark IC, Folinais D, Tahar IN, Pour AE. What is the impact of a spinal fusion on acetabular implant orientation in functional standing and sitting positions? The Journal of Arthroplasty 2017; 32 (10): 3184-3190. doi: 10.1016/j. arth.2017.04.051