Morphometric study of rat sciatic nerve recovery after three nerve repair techniques: epineural suture, polyethylene glycol hydrogel and fibrin sealant / Estudio morfométrico de la recuperación del nervio ciático de rata después de tres técnicas de reparación nerviosa: sutura epineural, hidrogel de polietilenglicol y sellante de fibrina

SUMMARY: The effectiveness of microsurgical technique has a direct impact on the recovery of the injured peripheral nerve. The aim of our study was to investigate the result of sciatic nerve regeneration in rats after complete neurotomy and after nerve repair techniques including: 1) epineural suture; 2) polyethylene glycol hydrogel (PEG) (DuraSeal); 3) fibrin sealant (Tisseel). The cross-section of distal sciatic nerve was studied at 14th, 30th and 60th days after nerve repair. Morphometry of myelinated nerve fibers in the distal stump of the sciatic nerve was performed. A significant increase in the number of myelinated nerve fibers was found, especially between 14 and 30 days. The density of myelinated nerve fibers in the distal stump at day 60 was significantly higher after using nerve repair technique including PEG and fibrin versus epineural suture (29.2 % and 32.1 % versus 21.5 %, P <0.05), and a higher level of remyelination of nerve fibers observed in the group with PEG. On day 60, complete elimination of PEG and fibrin sealant was not observed, encapsulation was found around the clusters of hydrogel. Thereby, three peripheral nerve repair techniques were equally effective, only with the use of PEG remyelination of nerve fibers was increasing.

RESUMEN: La efectividad de la técnica microquirúrgica tiene un impacto directo en la recuperación del nervio periférico lesionado. El objetivo de nuestro estudio fue investigar el resultado de la regeneración del nervio ciático en ratas después de una neurotomía completa y después de técnicas de reparación nerviosa que incluyeron: 1) sutura epineural; 2) hidrogel de polietilenglicol (PEG) (DuraSeal); 3) sellante de fibrina (Tisseel). La sección transversal del nervio ciático distal se estudió a los 14, 30 y 60 días después de la reparación del nervio. Se realizó la morfometría de fibras nerviosas mielinizadas en el muñón distal del nervio ciático. Se observó un aumento significativo en el número de fibras nerviosas mielinizadas, especialmente entre los 14 y 30 días. La densidad de las fibras nerviosas mielinizadas en el muñón distal en el día 60 fue significativamente mayor después de usar una técnica de reparación nerviosa que incluye PEG y fibrina en comparación con la sutura epineural (29,2 % y 32,1 % versus 21,5 %, P <0,05), y un mayor nivel de remielinización del nervio en fibras observadas en el grupo con PEG. El día 60, no se observó la eliminación completa de PEG y sellador de fibrina, se encontró encapsulación alrededor de los grupos de hidrogel. Por lo tanto, tres técnicas de reparación de nervios periféricos fueron igualmente efectivas, solo que aumentaba la remielinización de fibras nerviosas con PEG.

Reparação microcirúrgica de nervo facial de ratos Wistar por meio de sutura: parte 2 / Microsurgical reparation of Wistar rats facial nerve through suture: part 2

O nervo facial direito de 20 ratos da raça Wistar foi seccionado, e as extremidades foram aproximadas por um ponto simples inicial e envolvidas por uma bainha de BioFill. As mudanças histológicas observadas foram proliferação de tecido fibroso, invasão do tecido nervoso por mastócitos e fibroblastos e presença de fibrilas de colágeno. O uso da bainha de BioFill oferece vantagens porque é responsável pelo melhor direcionamento das fibras nervosas

The right-side facial nerve of 20 Wistar rats was trans-sectioned and, immediately treated with three plain epineural suture stitches. Analysis of the results was based on histopathological aspects of the anastomotic area. It was noticed that the presence of the suture material was responsible for the poor directioning of the nerve fibers and the neuroma formation in the anastomosis area, due to the collision of the regenerating nerve fibers with the granulomatous reaction to the suture string. Wallerian degeneration and proliferation of fibrous tissue were noticed

Reparação microcirúrgica de nervo facial de ratos Wistar por meio de sutura: parte 1 / Microsurgical reparation of facial nerve os Wistar rat with suture: part 1

O nervo facial direito de 20 ratos da raça Wistar foi seccionado e imediatamente tratado com três pontos de sutura epineurais. A análise dos resultados foi baseada no aspecto histopatológico da área anastomótica. Percebe-se que a presença do material de sutura foi responsável pelo pobre direcionamento das fibras nervosas e formação de neuroma na área de anastomose em virtude da colisão das fibras nervosas em regeneração com a reação granulomatosa ao fio de sutura. Alterações como degeneração walleriana e proliferação de tecido fibroso foram observadas

The right-side facial nerve of 20 Wistar rats was trans-sectioned and, immediately treated with three plain epineural suture stitches. Analysis of the results was based on histopathological aspects of the anastomotic area. It was noticed that the presence of the suture material was responsible for the poor directioning of the nerve fibers and the neuroma formation in the anastomosis area, due to the collision of the regenerating nerve fibers with the granulomatous reaction to the suture string. Wallerian degeneration and proliferation of fibrous tissue were noticed.