Pediatric spinal cord injury in infant piglets: description of a new large animal model and review of the literature.
OBJECTIVE
To develop a new, clinically relevant large animal model of pediatric spinal cord injury (SCI) and compare the clinical and experimental features of pediatric SCI.


METHODS
Infant piglets (3-5 weeks old) underwent contusive SCI by controlled cortical impactor at T7. Severe complete SCI was induced in 6 piglets, defined as SCI with no spontaneous return of sensorimotor function. Eight piglets received incomplete SCI, which was followed by partial recovery. Somatosensory evoked potentials, magnetic resonance imaging, neurobehavioral function, and histopathology were measured during a 28-day survival period.


RESULTS
Mean SCI volume (defined as volume of necrotic tissue) was larger after complete compared with incomplete SCI (387 +/- 29 vs 77 +/- 38 mm3, respectively, P < 0.001). No functional recovery occurred after complete SCI. After incomplete SCI, piglets initially had an absence of lower extremity sensorimotor function, urinary and stool retention, and little to no rectal tone. Sensory responses recovered first (1-2 days after injury), followed by spontaneous voiding, lower extremity motor responses, regular bowel movements, and repetitive flexion-extension of the lower extremities when crawling. No piglet recovered spontaneous walking, although 4 of 8 animals with incomplete injuries were able to bear weight by 28 days. In vivo magnetic resonance imaging was performed safely, yielded high-resolution images of tissue injury, and correlated closely with injury volume seen on histopathology, which included intramedullary hemorrhage, cellular inflammation, necrosis, and apoptosis.


CONCLUSIONS
Piglets performed well as a reproducible model of traumatic pediatric SCI in a large animal with chronic survival and utilizing multiple outcome measures, including evoked potentials, magnetic resonance imaging, functional outcome scores, and histopathology.
Kuluz
John
J
Pediatric Critical Care (R-131), University of Miami School of Medicine, 1611 NW 12th Avenue, Miami, FL 33136, USA. jkuluz@bellsouth.net
Samdani
Amer
A
Benglis
David
D
Gonzalez-Brito
Manuel
M
Solano
Juan P
JP
Ramirez
Miguel A
MA
Luqman
Ali
A
De los Santos
Roosevelt
R
Hutchinson
David
D
Nares
Mike
M
Padgett
Kyle
K
He
Dansha
D
Huang
Tingting
T
Levi
Allan
A
Betz
Randal
R
Dietrich
Dalton
D
D000344:Afferent Pathways / Q000503:physiopathology; D000818:Animals; D000831:Animals, Newborn; D000842:Ankle / Q000294:innervation; D004195:Disease Models, Animal; D004569:Electroencephalography / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D006801:Humans; D007796:Laminectomy / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D009460:Neurologic Examination; D010372:Pediatrics; D020127:Recovery of Function; D013116:Spinal Cord / Q000473:pathology; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D013552:Swine; D013997:Time Factors; D016138:Walking / Q000502:physiology
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