Técnicas de neurorrafia: estudo experimental estereológico axonal comparativo

Abstract

There are many varieties of lesions of the peripheral nerves derived from acquired or congenital degenerate diseases which can affect the central nervous system and can cause loss of sensory and motor functions. The aim of this work was to make an experimental stereological study of the axons after end-to-side neurorrhaphies and after side-to-side neurorrhaphies to compare the axon, endoneural and myelin sheath volume densities (as well as the muscle mass) in the fibular and tibial nerves with contact anastomosis between 0.25cm and 0.50 cm. After approval by the Ethics Committee, twenty male Wistar rats were divided into four distinct groups of five rats each for the anastomosis between the tibial and fibular nerves (G1= end-to-side neurorrhaphy; G2= 0.25cm side-to-side neurorrhaphy; G3= 0.50cm side-to-side neurorrhaphy and G4= control group of normality and denervation). After 180 days, nervous fragments were fixed in 10% formaldehyde included in paraffin and stained with Masson's trichrome tecnique for the stereological study by the software Image Pro Plus ® version 6.0 with the adoption of Weibel stereological grid to set the axon, endoneural and myelin sheath volume densities. The Mann-Whitney (U Test) was applied for the statistical analysis. Also tibial cranial muscles were removed and then weighed in a precision scale. There was no statistically significant difference between the groups, but there were significant differences comparing the 3 groups (G1, G2 e G3) to the control group (G4). The axon, enduneral and myelin sheath volume densities of tibial and fibular nerves as well as the muscle mass during postoperative period keep egalitarian for both end-to-side and side-to-side neurorrhaphies of anastomosis area of contact in experimental stereological study comparing neurorrhaphies. Therefore, both end-to-side neurorrhaphies (which recover and prevent the motor atrophy) and side-to-side l neurorrhaphies which is independent on the gap of the nerve stumps are recommended as surgical treatment options.