Abstract
Simple SummaryGuinea pigs are popular pets, but there is still a lack of information about their morphology. Variable morphology of the vertebral column can lead to incorrect localization of spinal diseases or the site of surgical intervention. This study aimed to determine the numerical variants of vertebral column and prevalence, localization, and type of congenital anomalies of the vertebral column. Vertebral column radiographs were reviewed in 240 guinea pigs, and nine numerical variants of the vertebral column were noticed. The most common vertebral formula, seven cervical, 13 thoracic, six lumbar, four sacral, and five to seven caudal vertebrae, was found in 75% of guinea pigs. Congenital anomalies were also found as incidental findings in 12.5% of guinea pigs, mostly in the thoracolumbar and lumbosacral regions. The most common congenital anomalies were a variable morphology of the last pair of ribs in the thoracolumbar region and transitional vertebra with a mixed morphological characteristic of lumbar and sacral vertebrae in the lumbosacral region. The cervical region was the least common region for congenital anomalies of the vertebral column. Our results contribute to the knowledge of clinical morphology in guinea pigs applicable in both, research and clinical practice.The objectives of this retrospective study of 240 guinea pigs (148 females and 92 males) were to determine the prevalence of different vertebral formulae and the type and anatomical localization of congenital vertebral anomalies (CVA). Radiographs of the cervical (C), thoracic (Th), lumbar (L), sacral (S), and caudal (Cd) part of the vertebral column were reviewed. Morphology and number of vertebrae in each segment of the vertebral column and type and localization of CVA were recorded. In 210/240 guinea pigs (87.50%) with normal vertebral morphology, nine vertebral formulae were found with constant number of C but variable number of Th, L, and S vertebrae: C7/Th13/L6/S4/Cd5-7 (75%), C7/Th13/L6/S3/Cd6-7 (4.17%), C7/Th13/L5/S4/Cd6-7 (2.50%), C7/Th13/L6/S5/Cd5-6 (1.67%), C7/Th12/L6/S4/Cd6 (1.25%), C7/Th13/L7/S4/Cd6 (1.25%), C7/Th13/L7/S3/Cd6-7 (0.83%), C7/Th12/L7/S4/Cd5 (0.42%), C7/Th13/L5/S5/Cd7 (0.42%). CVA were found in 30/240 (12.5%) of guinea pigs, mostly as a transitional vertebra (28/30), which represents 100% of single CVA localised in cervicothoracic (n = 1), thoracolumbar (n = 22) and lumbosacral segments (n = 5). Five morphological variants of thoracolumbar transitional vertebrae (TTV) were identified. Two (2/30) guinea pigs had a combination of CVA: cervical block vertebra and TTV (n = 1) and TTV and lumbosacral transitional vertebra (LTV) (n = 1). These findings suggest that guinea pigs’ vertebral column displays more morphological variants with occasional CVA predominantly transitional vertebrae.
Highlights
Guinea pig (Cavia porcellus) is traditionally used as a food animal [1] and the animal model in biomedical research [2]
The objectives of the present study were to determine the prevalence of different vertebral formulae of the axial skeleton in pet guinea pigs and to evaluate the radiographic prevalence, type, and anatomical localization of naturally occurring congenital vertebral anomalies (CVA) including morphology of the last pair of ribs in guinea pigs
Fifty-six vertebral columns were reviewed from wholebody radiographs and 184 vertebral columns from sequential, overlapping radiographs of head, thorax, and abdomen
Summary
Guinea pig (Cavia porcellus) is traditionally used as a food animal [1] and the animal model in biomedical research [2]. Guinea pigs are kept as house pets, a worldwide phenomenon [3,4]. Guinea pigs are the 6th most common treated animal species in veterinary practice in the United Kingdom [5]. Despite their popularity as pets and laboratory animals, there is still a lack of information about their morphology [6]. Scientific texts lack information on the prevalence of specific vertebral formulae and the prevalence, type, and localization of congenital vertebral anomalies (CVA) Rodents are traditionally considered least variable mammals with a fixed number of seven cervical (C) and a total of 19 thoracolumbar vertebrae [7], varying number of thoracic (T), lumbar (L), sacral (S), and caudal (Cd) part of the vertebral column was previously published and summarised as following vertebral formula C7/T12-14/L6/S2S4/Cd4-7 [4,8,9,10,11,12].
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