Sciatic nerve histological study in experimental femoral lengthening by combined osteosynthesis method

UDC [636.7:616.718.4-001.5-089.227.84:616.833.58] -092.9

Varsegova T.N., Stepanov M.A., Antonov N.I.

Summary. Treatment of dogs with large defects of the limb bones for their congenital shortenings, injury consequences and primary tumors is still a relevant problem. Combined distraction osteosynthesis of canine femur using an external fixator and an internal plate with a longitudinal slot demonstrated high effectiveness because it reduced the risk of fractures of regenerated bone in different periods of its formation, as well as prevented articular contractures due to earlier limb weight-bearing. There is no information in the available literature concerning the sciatic nerve changes when using this technique of canine femoral lengthening. This determined the purpose of the present work. The experiment was performed in 6 adult mongrel dogs subjected to femoral lengthening for 25 days with the rate of 1 mm for 4 приёма by 10% of initial bone length using the technique of combined distraction osteosynthesis with the external fixator and internal plate. The sciatic nerves were studied after 30 and 90 days of the regenerated bone fixation with the internal plate. There were no cases of the sciatic nerve neuropathy. The proportion of destructively changed myelin fibers on the average amounted to 4.17% (30 days of fixation) and 3.99% (90 days of fixation), thereby evidencing of good preservation of nerve conductors. The revealed increase in myelin fiber numerical density, cellularity and vascularization of nerve membranes is a compensatory-adaptive response of nerve trunks to osteotomy, distraction osteosynthesis, internal plate. The technique of canine femoral distraction osteosynthesis with the external fixator and the original internal plate of titanium alloy is sparing for the sciatic nerve.

Keywords: dog, experiment, femoral lengthening, internal plate, external fixation, sciatic nerve, myelin fibers, histological study.

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Author affiliation:

Antonov Nikolay I., Ph.D. in Biology, scientific researcher of the experimental laboratory of the Russian Scientific Center for Restorative Traumatology and Orthopaedics named after G.A. Ilizarov of the Ministry of Health of the Russian Federation; 6, M. Ulyanova st., Kurgan, 640014; phone: 8-3522-45-41-71; e-mail: aniv-niko@mail.ru.

Stepanov Mikhail A., Ph.D. in Veterinary Medicine, leading scientific researcher of the experimental laboratory of the Russian Scientific Center for Restorative Traumatology and Orthopaedics named after G.A. Ilizarov of the Ministry of Health of the Russian Federation; 6, M. Ulyanova st., Kurgan, 640014; phone: 8-3522-45-41-71; e-mail: m-stepanov@mail.ru.

Responsible for correspondence with the editorial board: Varsegova Tatiana N., Ph.D. in Biology, senior scientific researcher of the Laboratory of Morphology of the Russian Scientific Center for Restorative Traumatology and Orthopaedics named after G.A. Ilizarov of the Ministry of Health of the Russian Federation; 6, M. Ulyanova st., Kurgan, 640014; phone: 8-3522-41-52-73; e -mail: varstn@mail.ru.