Computed tomographic evaluation of safe corridors for pin placement in rabbit thoracolumbar vertebrae and sacrum

Vertebral fractures comprise approximately one-fourth of all non-pathologic fractures in rabbits, and they are most commonly associated with improper restraint. Due to the anatomy of the spine and their powerful hind quarter, most fractures occur in the lumbar region. The prognosis is generally poor due to the clinical signs – paresis or paralysis, urinary and fecal incontinence, and decubitus ulcers – and lack of reliable treatment options, often resulting in euthanasia. There is a lack of literature and experience in surgical fixation of rabbit vertebrae. The objective of this study is to identify safe ventral corridors for pin placement in the thoracic and lumbar vertebrae and sacrum of rabbits using computed tomography (CT) in cadaveric models to better understand surgical approaches to spinal stabilization. Twenty-five adult New Zealand white rabbits (Oryctolagus cuniculi) were evaluated using advanced imaging (CT). Measurements and safe ventral corridors were determined using a multiplanar reconstructions generated with standard picture archiving and communication system (PACS) and reformatted in dorsal and sagittal planes using the OsiriX multiplanar reconstruction tool. Implants were placed tangentially to the vertebral canal, or 90 degrees relative to the sagittal midline, to allow maximal bone purchase within the safe corridors. CT imaging was repeated to evaluate for canal impingement and other errors. The median and range of the safe corridor height in the thoracic and lumbar cranial end cortical section (ECS) of the vertebrae (2.54mm; 1.39–3.97mm) was significantly lower than that of the caudal ECS (3.98mm; 1.66–5.53mm; p < 0.001). The mean widths of the left and right sacral safe corridors were not significantly different. Of the 99 pins placed, 70.7% (70/99) of the pins were appropriately placed without vertebral canal impingement. Errors included partial canal impingement (12.1%, 12/99), complete canal impingement (5.1%, 5/99), inadequate bone purchase (7.1%, 7/99), placement into the intervertebral disc space (1.0%, 1/99) or in the incorrect ECS than intended (4.0%, 4/99). The odds ratio of successful pin insertion without canal impingement was 2.77 (95% CI, 1.04–7.43; p < 0.05) times higher in the caudal ECS than in the cranial ECS. The corridor identified in this study can be used as a guideline for pin placement in the thoracic and lumbar vertebrae of New Zealand white rabbits.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

VMS-Veterinary Clinical Medcne

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Chen, Monica

Contributors dc:contributor

• Moran, Clara E
• Gal, Arnon
• Keller, Krista K
• Foss, Kari D

• Rabbit
• Vertebrae
• Vertebral Fracture And Luxation
• Pins

Statement dc:rights

• Copyright 2023 Monica Chen

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/122160

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F122160