Development of a Rat Caudal Interbody Fusion Model: A Pilot Feasibility Study.

Area of Science:

• Orthopedics
• Biomaterials Science
• Regenerative Medicine

Background:

• Rat caudal vertebrae are common models for bone regeneration and spinal fusion research.
• Existing rat tail fusion models lack interbody cages used in clinical settings.
• A clinically analogous small-animal model is needed for evaluating fusion devices.

Purpose of the Study:

• To develop and assess the technical feasibility of a novel rat caudal vertebrae fusion model using an interbody cage.
• To mimic clinical posterior cage insertion procedures in a small-animal model.
• To establish an evaluable bone fusion environment without neurological complications.

Main Methods:

• A miniaturized titanium interbody cage was inserted into the resected disc space of rat caudal vertebrae.
• Posterior cage insertion was supplemented with plate fixation.
• Radiological and histological analyses were performed to assess bone fusion and ingrowth.

Main Results:

• The surgical approach demonstrated technical feasibility, with the cage maintaining disc height and spinal alignment.
• Progressive bone ingrowth through the cage was observed.
• Continuous bone bridging across the intervertebral space was confirmed by 12 weeks postoperatively.

Conclusions:

• This cage-based rat tail fusion model is a promising platform for evaluating bone graft materials and studying intervertebral fusion mechanisms.
• The model successfully replicated clinical procedures, offering a viable alternative to existing methods.
• Further validation with control groups and statistical analysis is required to generalize findings.