Medial canthopexy: an experimental and biomechanical study

Area of Science:

• Ophthalmology
• Plastic Surgery
• Biomechanics

Background:

• Medial canthopexy, a surgical procedure to reattach the medial canthal tendon, has a notable failure rate.
• Understanding the biomechanical properties of the medial canthal tendon is crucial for improving surgical outcomes.

Purpose of the Study:

• To evaluate the biomechanics of the medial canthal tendon.
• To assess the biomechanical strength of three different fixation devices used in medial canthopexy.

Main Methods:

• A cadaveric study using four fresh-frozen human heads (eight medial canthal tendons).
• Assessment of the native medial canthal tendon's strength and elongation.
• Testing of three medial canthopexy fixation techniques: transnasal wire over a button, 1.7-mm screw fixation, and Mitek GII anchor.

Main Results:

• The medial canthal tendon demonstrated a high average breaking strength (36 N) and elongation (6.25 mm), indicating greater strength than previously thought.
• The tendon-bone complex exhibited closely matched biomechanical properties.
• Fixation strengths were 74% (wire), 92% (screw), and 97% (Mitek anchor) of the intact tendon's strength.
• All three tested fixation devices provided excellent ultimate biomechanical strength.

Conclusions:

• The medial canthal tendon is biomechanically robust.
• Current fixation devices for medial canthopexy offer substantial strength, suggesting potential for improved clinical success rates.
• Further clinical correlation is warranted to fully understand the implications of these biomechanical findings.