A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study

Area of Science:

• Veterinary Surgery
• Biomaterials Science
• Orthopedic Research

Background:

• Mandibular defects pose significant challenges in reconstructive surgery.
• Locking screw-plate systems are commonly used for mandibular reconstruction.
• Evaluating the biomechanical stability and failure modes of these systems is crucial.

Purpose of the Study:

• To assess the clinical and radiological performance of four different mandibular screw-plate locking systems.
• To identify potential failure points, such as plate or screw fractures and bone resorption, in these systems.
• To compare the efficacy and limitations of the tested mandibular reconstruction systems.

Main Methods:

• Surgical creation of 3-4 cm mandibular defects in sheep.
• Reconstruction of defects using four distinct pre-bent angular reconstruction plate systems.
• Fixation with four screws in the mandibular body and three in the ramus for each plate type.
• Clinical and radiological evaluation at 1 and 2 months post-surgery.

Main Results:

• All sheep maintained normal eating and rumination post-operation.
• Fractures occurred in 6 out of 16 plates and 5 out of 112 screws across tested systems.
• One specific plate system exhibited no fractures.
• Slight to moderate bone resorption under the plate was observed in 6 of 16 mandibles.

Conclusions:

• The tested mandibular screw-plate locking systems demonstrate internal shortcomings.
• While functionally adequate for basic functions, mechanical failures (fractures) limit their long-term reliability.
• Further improvements in the design of mandibular reconstruction plates are warranted based on these findings.