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Characterization of a Pre-Clinical Mini-Pig Model of Scaphoid Non-Union.

Behrends DA, Khendek L, Gao C, Zayed N, Henderson JE, Martineau PA - J Funct Biomater (2015)

Bottom Line: A 3 mm osteotomy of the radiocarpal bone was generated and treated with immediate fixation or filled with a dense collagen gel followed by delayed fixation.With immediate fixation, the osteotomy site was filled with new bone across its whole length resulting in complete bridging.The dense collagen gel, previously shown to impede neo-vascularization, followed by delayed fixation resulted in impaired bridging with less bone of lower quality.

View Article: PubMed Central - PubMed

Affiliation: Bone Engineering Labs, Research Institute-McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec H3G 1A4, Canada. domi.behrends@gmail.com.

ABSTRACT
A fractured scaphoid is a common disabling injury that is frequently complicated by non-union. The treatment of non-union remains challenging because of the scaphoid's small size and delicate blood supply. Large animal models are the most reliable method to evaluate the efficacy of new treatment modalities before their translation into clinical practice. The goal of this study was to model a human scaphoid fracture complicated by non-union in Yucatan mini-pigs. Imaging and perfusion studies were used to confirm that the anatomy and blood supply of the radiocarpal bone in mini-pigs were similar to the human scaphoid. A 3 mm osteotomy of the radiocarpal bone was generated and treated with immediate fixation or filled with a dense collagen gel followed by delayed fixation. Bone healing was assessed using quantitative micro computed tomography and histology. With immediate fixation, the osteotomy site was filled with new bone across its whole length resulting in complete bridging. The dense collagen gel, previously shown to impede neo-vascularization, followed by delayed fixation resulted in impaired bridging with less bone of lower quality. This model is an appropriate, easily reproducible model for the evaluation of novel approaches for the repair of human scaphoid fractures.

No MeSH data available.


Related in: MedlinePlus

High resolution radiographs comparing human scaphoid and mini-pig radiocarpal bone: The position of the scaphoid bone in the human wrist (A,B), and the corresponding radiocarpal bone in a porcine forelimb (C,D) are marked by arrows in 2D X-rays (A,C) and 3D models (B,D). For contrast radiography pigs were euthanized, and the forelimbs perfused immediately with BaSO4 via the axillary artery. The carpal bones were scanned at high resolution on a Skyscan 1172 ex vivo instrument (E) and on a Fidex Animage in vivo instrument (F). The position and size of the pig radiocarpal bone closely resemble those of the human scaphoid bone, but differ in orientation of the longitudinal axis. As with the human scaphoid, the pig radiocarpal bone has a limited blood supply to the volar pole indicated by arrows on the 3D reconstructions (E,F).
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jfb-06-00407-f001: High resolution radiographs comparing human scaphoid and mini-pig radiocarpal bone: The position of the scaphoid bone in the human wrist (A,B), and the corresponding radiocarpal bone in a porcine forelimb (C,D) are marked by arrows in 2D X-rays (A,C) and 3D models (B,D). For contrast radiography pigs were euthanized, and the forelimbs perfused immediately with BaSO4 via the axillary artery. The carpal bones were scanned at high resolution on a Skyscan 1172 ex vivo instrument (E) and on a Fidex Animage in vivo instrument (F). The position and size of the pig radiocarpal bone closely resemble those of the human scaphoid bone, but differ in orientation of the longitudinal axis. As with the human scaphoid, the pig radiocarpal bone has a limited blood supply to the volar pole indicated by arrows on the 3D reconstructions (E,F).

Mentions: Radiologic images and 3D representations (Figure 1) of the adult human hand (Figure 1A,B) and mini-pig forelimb (Figure 1C,D) reveal a remarkable similarity in anatomy, particularly of the complex structure of the carpal bones in the wrist. The human scaphoid corresponds to the mini-pig radiocarpal bone (arrows Figure 1A–D), which is located between the radius and the metacarpal bones. BaSO4 contrast agent injected into the axillary artery to visualize the vascular feed to the radiocarpal (Figure 1E,F) confirmed the same organization of retrograde blood supply as seen in the human scaphoid. Reconstruction of high resolution micro CT images (Figure 1E) confirmed the position of the supply artery, originating from the large vessels on the volar side of the wrist and entering the dorsal aspect of the radiocarpal bone. The intraosseous vessel then runs from dorsal to volar analogous to the retrograde flow of the radial artery blood supply in the human scaphoid, leaving the volar pole vulnerable to avascular necrosis. The course of the blood vessels was confirmed on transaxial CT images captured with the Fidex Animage CT scanner (Figure 1F). The radiocarpal bone was, thus, shown to resemble the human scaphoid bone and the mini-pig identified as an appropriate pre-clinical model to replicate fracture non-union of the human scaphoid to develop improved therapeutic interventions for repair.


Characterization of a Pre-Clinical Mini-Pig Model of Scaphoid Non-Union.

Behrends DA, Khendek L, Gao C, Zayed N, Henderson JE, Martineau PA - J Funct Biomater (2015)

High resolution radiographs comparing human scaphoid and mini-pig radiocarpal bone: The position of the scaphoid bone in the human wrist (A,B), and the corresponding radiocarpal bone in a porcine forelimb (C,D) are marked by arrows in 2D X-rays (A,C) and 3D models (B,D). For contrast radiography pigs were euthanized, and the forelimbs perfused immediately with BaSO4 via the axillary artery. The carpal bones were scanned at high resolution on a Skyscan 1172 ex vivo instrument (E) and on a Fidex Animage in vivo instrument (F). The position and size of the pig radiocarpal bone closely resemble those of the human scaphoid bone, but differ in orientation of the longitudinal axis. As with the human scaphoid, the pig radiocarpal bone has a limited blood supply to the volar pole indicated by arrows on the 3D reconstructions (E,F).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493521&req=5

jfb-06-00407-f001: High resolution radiographs comparing human scaphoid and mini-pig radiocarpal bone: The position of the scaphoid bone in the human wrist (A,B), and the corresponding radiocarpal bone in a porcine forelimb (C,D) are marked by arrows in 2D X-rays (A,C) and 3D models (B,D). For contrast radiography pigs were euthanized, and the forelimbs perfused immediately with BaSO4 via the axillary artery. The carpal bones were scanned at high resolution on a Skyscan 1172 ex vivo instrument (E) and on a Fidex Animage in vivo instrument (F). The position and size of the pig radiocarpal bone closely resemble those of the human scaphoid bone, but differ in orientation of the longitudinal axis. As with the human scaphoid, the pig radiocarpal bone has a limited blood supply to the volar pole indicated by arrows on the 3D reconstructions (E,F).
Mentions: Radiologic images and 3D representations (Figure 1) of the adult human hand (Figure 1A,B) and mini-pig forelimb (Figure 1C,D) reveal a remarkable similarity in anatomy, particularly of the complex structure of the carpal bones in the wrist. The human scaphoid corresponds to the mini-pig radiocarpal bone (arrows Figure 1A–D), which is located between the radius and the metacarpal bones. BaSO4 contrast agent injected into the axillary artery to visualize the vascular feed to the radiocarpal (Figure 1E,F) confirmed the same organization of retrograde blood supply as seen in the human scaphoid. Reconstruction of high resolution micro CT images (Figure 1E) confirmed the position of the supply artery, originating from the large vessels on the volar side of the wrist and entering the dorsal aspect of the radiocarpal bone. The intraosseous vessel then runs from dorsal to volar analogous to the retrograde flow of the radial artery blood supply in the human scaphoid, leaving the volar pole vulnerable to avascular necrosis. The course of the blood vessels was confirmed on transaxial CT images captured with the Fidex Animage CT scanner (Figure 1F). The radiocarpal bone was, thus, shown to resemble the human scaphoid bone and the mini-pig identified as an appropriate pre-clinical model to replicate fracture non-union of the human scaphoid to develop improved therapeutic interventions for repair.

Bottom Line: A 3 mm osteotomy of the radiocarpal bone was generated and treated with immediate fixation or filled with a dense collagen gel followed by delayed fixation.With immediate fixation, the osteotomy site was filled with new bone across its whole length resulting in complete bridging.The dense collagen gel, previously shown to impede neo-vascularization, followed by delayed fixation resulted in impaired bridging with less bone of lower quality.

View Article: PubMed Central - PubMed

Affiliation: Bone Engineering Labs, Research Institute-McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec H3G 1A4, Canada. domi.behrends@gmail.com.

ABSTRACT
A fractured scaphoid is a common disabling injury that is frequently complicated by non-union. The treatment of non-union remains challenging because of the scaphoid's small size and delicate blood supply. Large animal models are the most reliable method to evaluate the efficacy of new treatment modalities before their translation into clinical practice. The goal of this study was to model a human scaphoid fracture complicated by non-union in Yucatan mini-pigs. Imaging and perfusion studies were used to confirm that the anatomy and blood supply of the radiocarpal bone in mini-pigs were similar to the human scaphoid. A 3 mm osteotomy of the radiocarpal bone was generated and treated with immediate fixation or filled with a dense collagen gel followed by delayed fixation. Bone healing was assessed using quantitative micro computed tomography and histology. With immediate fixation, the osteotomy site was filled with new bone across its whole length resulting in complete bridging. The dense collagen gel, previously shown to impede neo-vascularization, followed by delayed fixation resulted in impaired bridging with less bone of lower quality. This model is an appropriate, easily reproducible model for the evaluation of novel approaches for the repair of human scaphoid fractures.

No MeSH data available.


Related in: MedlinePlus