Morphofunctional Changes in the Tibial and Peroneal Nerves in Shin Lengthening Using High Speed Daily Distraction...

Area of Science:

• Orthopedic surgery
• Neuroscience
• Veterinary medicine

Background:

• Limb lengthening procedures are crucial in orthopedics.
• Understanding nerve responses during distraction osteogenesis is vital for patient outcomes.

Purpose of the Study:

• To investigate the effects of Ilizarov external fixator-assisted tibial lengthening on peripheral nerve integrity in dogs.
• To quantify changes in nerve electrophysiology and histology.

Main Methods:

• Dogs underwent tibial lengthening using an Ilizarov external fixator with automated distraction (3 mm/day).
• Electrophysiological measurements of M-response amplitudes in gastrocnemius and tibialis anterior muscles were recorded.
• Histological analysis of tibial and peroneal nerves was performed to assess structural changes.

Main Results:

• A sustained decrease in M-response amplitudes was observed in the gastrocnemius and tibialis anterior muscles.
• Tibial nerve analysis revealed transverse contraction (13.2%), endoneural hypervascularization (28-95%), axonal degeneration, and myelin decompactization, with <5% fiber destruction.
• Peroneal nerve exhibited greater contraction (17.3%), endoneurium hypovascularization (12%), axonal degeneration, demyelination, and >20% fiber destruction in 6/9 experiments.

Conclusions:

• Ilizarov external fixator-assisted tibial lengthening can induce significant peripheral nerve alterations in dogs.
• The peroneal nerve appears more susceptible to damage during this procedure compared to the tibial nerve.
• These findings highlight the importance of monitoring nerve function and structure during limb lengthening protocols.