Biodegradable polyglyconate plates and screws: a histological evaluation in a rabbit model

Area of Science:

• Biomaterials Science
• Surgical Pathology
• Veterinary Medicine

Background:

• Zygomatic arch osteotomies are surgical procedures involving bone cuts in the cheekbone.
• Polyglyconate acid (PGA) is a biodegradable synthetic polymer used in surgical implants.
• Understanding the long-term tissue response to PGA implants is crucial for surgical outcomes.

Purpose of the Study:

• To histologically evaluate the tissue response to polyglyconate acid plates and screws used for zygomatic arch osteotomy stabilization in rabbits.
• To assess the degradation and foreign body reaction to PGA implants over a 12-month period.

Main Methods:

• Bilateral osteotomies were performed on the zygomatic arches of 20 New Zealand white rabbits.
• Implants were stabilized using polyglyconate acid plates and screws.
• Zygomatic complexes were harvested at 3, 4, 6, 9, and 12 months post-surgery.
• Histological examination of serial sections was conducted to assess tissue reactions.

Main Results:

• No gross adverse reactions were observed during the study period.
• Histological examination revealed a foreign body giant cell reaction to particulate material at 3 months.
• By 4 months, the foreign body reaction was partially replaced by fibrous tissue, with a decrease in visible foreign material.
• At 6 months, a thick periosteal scar was present, with residual foreign material within vesicular spaces and histiocyte infiltration.
• By 12 months, the acute foreign body reaction had subsided, but small foci of chronic inflammation persisted.

Conclusions:

• Polyglyconate acid implants elicit a transient foreign body reaction following zygomatic arch osteotomy in rabbits.
• The reaction progresses from acute inflammation to fibrous encapsulation and eventual chronic inflammation.
• These findings suggest a need for careful consideration of long-term tissue responses to biodegradable implants in craniofacial surgery.