Biomechanical Comparison Between Bicortical Pin and Monocortical Screw/Polymethylmethacrylate Constructs in the Cadaveric Canine Cervical Vertebral Column

Abstract

ObjectiveTo compare biomechanical stiffness of cadaveric canine cervical spine constructs stabilized with bicortical stainless steel pins and polymethylmethacrylate (PMMA), monocortical stainless steel screws with PMMA, or monocortical titanium screws with PMMA. Study DesignBiomechanical cadaver study. AnimalsEighteen canine cervical vertebral columns (C2-C7) were collected from skeletally mature dogs (weighing 22-32 kg). MethodsSpecimens were radiographed and examined by dual energy X-ray absorptiometry. Stiffness of the unaltered C4-C5 intervertebral motion unit was measured in extension, flexion and lateral bending using non-destructive 4-point bend testing. Specimens were then stabilized by (1) bicortical stainless steel pins/PMMA, (2) monocortical stainless steel screws/PMMA, or (3) monocortical titanium screws/PMMA. Mechanical testing was repeated and stiffness data from unaltered specimens and the 3 treatment groups were compared.

A novel patient‐specific drill guide template for stabilization of thoracolumbar vertebrae of dogs: cadaveric study and clinical cases

“…Spinal cord decompression followed by vertebral fixation techniques is the treatment of choice for severe cases . Vertebral fixation is achieved by implants, such as pins or screws, placed within the pedicles or vertebral bodies and polymethylmethacrylate, stainless, or titanium plates . These surgical instruments provide rigid and immediate intervertebral fixation and lead to satisfactory outcomes in most clinical cases but carry a potential risk of iatrogenic injury to vital structures, including the vasculature, nerve roots, and spinal cord .…”

“…The increased expense of this equipment likely plays a role in their limited adoption in veterinary medicine at the current time, and, hence, free‐hand implant placement is common in spinal fixation surgeries . However, free‐hand implantation for spinal fixation may result in iatrogenic injury to the spinal cord, nerve roots, and large vessels, which may lead to serious complications . In addition, anatomical variations in canine vertebrae across different breeds and various malformations in vertebrae make accurate implant placement challenging .…”

Accuracy of a patient‐specific 3D printed drill guide for placement of cervical transpedicular screws

“…[21][22][23] In a cadaveric study comparing the biomechanics of bicortical pins and monocortical screws with PMMA placed free-hand in the canine cervical vertebral column, 100% of bicortical pins violated the vertebral canal compared with a much lower incidence after monocortical screw fixation. 32 The angles for ideal screw insertion are of limited use in dogs, because of conflicting reports, inter-and intra-breed anatomical variations, and rotational effects of both surgical positioning and intraoperative probing or screwing on vertebral alignment. 14,33,34 Consequently, free-hand CPS placement in dogs is not recommended.…”

Hydroxyapatite-lignin composite as a metallic implant-bone tissue osseointegration improver: experimental study in dogs

“…Thus, combination of hydroxyapatite and lignin is expected to work as a resorbable bone cement promoting metallic implant osseointegration while supports bone regeneration, lowering the risks of implant loosening. The use of prostheses are growing in veterinary medicine, especially in rehabilitation of small animals, and loosening of metallic implants are important complications in dogs (HETTLICH et al, 2013). Therefore, the aim of the present study was to evaluate biocompatibility, osteoconductivity and osseointegration of a composite made of 20% hydroxyapatite and 80% lignin and its role in bone formation and anchoring of an intramedullary pin in dogs' tibia The presentation developed for this study would prevent the described problem and would allow to obtain biomaterial of low cost, thus more accessible.…”