Efectos de la eliminación de la tensión mediante puntos epineurales: estudio comparativo empleando diferentes técnicas de sutura en un modelo animal / Effects of tension elimination by using epineural anchoring stitches: a comparative study employing different techniques of suture in an experimental model

Objetivo. Documentar la utilidad de una técnica de sutura epineural bajo tensión, en comparación con la sutura mediante injerto interpuesto y la neurorrafia termino-terminal, en un estudio realizado en un modelo experimental animal (rata Wistar). Material y Método. Un lote de 20 animales, considerados como 40 unidades fisiológicas independientes a nivel del miembro inferior, fueron separados en 4 grupos de 10: en el primero se realizó una sutura bajo tensión con puntos epineurales a nivel del nervio ciático luego de resecar 4 mm de nervio. En el segundo se realizó una sutura término-terminal sin tensión, en el tercero se colocó un puente de injerto autólogo de 4 mm de extensión y el cuarto fue utilizado como control. A los 90 días de efectuados los procedimientos, se reexpusieron las zonas operadas y se documentaron las respuestas fisiológicas a los diferentes tipos de sutura mediante potenciales de acción de músculo (PAM) y nervio (PAN). Resultados. El promedio de la velocidad de conducción para la sutura simple fue el mejor de los tres grupos operados (14,60 mm/ ms), aunque peor que el control (19,31 mm/ms). La sutura a tensión mediante puntos epineurales (12,02 mm/ms) demostró resultados neurofisiológicos superiores que cuando se utilizó injerto autólogo (11,09 mm/ms). Conclusión. El presente estudio demuestra que si se logra coaptar un nervio ciático de rata mediante sutura epineural con puntos distales a la línea de neurorrafia, sus resultados son mejores que al emplear injerto. Sin embargo, estos resultados, obtenidos en un modelo de animal pequeño, deben ser cuidadosamente extrapolados a la práctica quirúrgica habitual.

Objective. To measure the utility of this technique, in comparison with interposed grafts and termino-terminal neuroraphy, all applied in an experimental model (Wistar rat).Materials and method. 20 rats were used in both sides (40 legs, each one considered as independent physiological units, were grouped in four groups: in the first one, a section of thesciatic nerve was performed, a segment 4mm long was discarded and an epineural suture with distal anchoring stitches was done under slight tension. In the second group a tensionlesstermino-terminal neuroraphy was performed after sciatic nerve section. In the third group a 4 mm long graft was employed and the fourth was used as control. 90 days after this procedure, the animals were reoperated and muscle and nerve action potentialswere recorded in both sides. Results. The mean conduction velocity for the simple suture was higher than the other two groups, but lower than the control(19,31 mm/ms). Neuroraphy with epineural stitches (12,02 mm/ms) was better than when an autologous nerve graft was employed (11,09 mm/ms).Conclusion. This study demonstrates that a good result can be obtained if a nerve is sutured under slight tension, employing epineural anchoring stitches. Nevertheless, more studies shouldbe performed before applying these results to human nerve suture.

Efectos de la eliminación de la tensión mediante puntos epineurales: estudio comparativo empleando diferentes técnicas de sutura en un modelo animal / Effects of tension elimination by using epineural anchoring stitches: a comparative study employing different techniques of suture in an experimental model

Objetivo. Documentar la utilidad de una técnica de sutura epineural bajo tensión, en comparación con la sutura mediante injerto interpuesto y la neurorrafia termino-terminal, en un estudio realizado en un modelo experimental animal (rata Wistar). Material y Método. Un lote de 20 animales, considerados como 40 unidades fisiológicas independientes a nivel del miembro inferior, fueron separados en 4 grupos de 10: en el primero se realizó una sutura bajo tensión con puntos epineurales a nivel del nervio ciático luego de resecar 4 mm de nervio. En el segundo se realizó una sutura término-terminal sin tensión, en el tercero se colocó un puente de injerto autólogo de 4 mm de extensión y el cuarto fue utilizado como control. A los 90 días de efectuados los procedimientos, se reexpusieron las zonas operadas y se documentaron las respuestas fisiológicas a los diferentes tipos de sutura mediante potenciales de acción de músculo (PAM) y nervio (PAN). Resultados. El promedio de la velocidad de conducción para la sutura simple fue el mejor de los tres grupos operados (14,60 mm/ ms), aunque peor que el control (19,31 mm/ms). La sutura a tensión mediante puntos epineurales (12,02 mm/ms) demostró resultados neurofisiológicos superiores que cuando se utilizó injerto autólogo (11,09 mm/ms). Conclusión. El presente estudio demuestra que si se logra coaptar un nervio ciático de rata mediante sutura epineural con puntos distales a la línea de neurorrafia, sus resultados son mejores que al emplear injerto. Sin embargo, estos resultados, obtenidos en un modelo de animal pequeño, deben ser cuidadosamente extrapolados a la práctica quirúrgica habitual.(AU)

Objective. To measure the utility of this technique, in comparison with interposed grafts and termino-terminal neuroraphy, all applied in an experimental model (Wistar rat).Materials and method. 20 rats were used in both sides (40 legs, each one considered as independent physiological units, were grouped in four groups: in the first one, a section of thesciatic nerve was performed, a segment 4mm long was discarded and an epineural suture with distal anchoring stitches was done under slight tension. In the second group a tensionlesstermino-terminal neuroraphy was performed after sciatic nerve section. In the third group a 4 mm long graft was employed and the fourth was used as control. 90 days after this procedure, the animals were reoperated and muscle and nerve action potentialswere recorded in both sides. Results. The mean conduction velocity for the simple suture was higher than the other two groups, but lower than the control(19,31 mm/ms). Neuroraphy with epineural stitches (12,02 mm/ms) was better than when an autologous nerve graft was employed (11,09 mm/ms).Conclusion. This study demonstrates that a good result can be obtained if a nerve is sutured under slight tension, employing epineural anchoring stitches. Nevertheless, more studies shouldbe performed before applying these results to human nerve suture.(AU)

Neurotropism following end-to-side neurorrhaphy by neuron retrograde tracing technique / 中华显微外科杂志

Objective To detect whether there is neurotropism following end-to-side neurorrhaphy by means of the neuron retrograde tracing technique. Methods Forty female Sprague-Dawley rats were randomly divided into 4 groups: tracing main branch of musculcutaneous nerve(MC) of end-to-side group, tracing MC main branch of normal group, tracing MC motor branch of end-to-side group and tracing MC motor branch of normal group.In two end-to-side groups, the MC was transeeted, then an 1 mm epineukral window was created on the ulnar nerve. Distal end of MC nerve was sutured to the windowed ulnar nerve by means of end-to-side neurorrhaphy.In two normal control groups, MC and ulnar nerves were just exposed. Five months post operation, by means of retrograde Fluoro-Gold neuron tracing technique,the number of C5～ T1 anterior horn motoneurons and dorsal root ganglion sensory neurons of all groups were counted. Results In two tracing MC main branch groups: the motor neuron counts in end-to-side group was 245.2 ± 93.8, the motor neuron counts in normal group was 846.7 ± 264.8, and counts of end-to-side group was 30.0% of the normal control group (P＜ 0.01). The sensory neuron counts in end-to-side was 434.7 ± 160.4, the sensory neuron counts in normal group was 1545.2 ± 287.4, and counts of end-to-side group was 28.1% of the normal control group (P ＜ 0.01). The per-centage of motor neuron in end-to-side group was 0.36 ± 0.09, there was no difference between end-to-side group and normal control group(P＞ 0.05). In two tracing MC motor branch groups: the motor neuron counts in end-to-side group was 72.3 ± 35.3, the motor neuron counts in normal group was 189.7 ± 57.0, and counts of end-to-side group was 38.1% of the normal control group (P ＜ 0.01). The sensory neuron counts in end-to-side was 110.8 ± 52.5, the sensory neuron counts in normal group was 157.9 ± 50.0, and counts of end-to-side group was 70.2% of the normal control group (P ＞ 0.05). The percentage of motor neuron in end-to-side group was 0.40 ± 0.14, the difference between end-to-side group and normal control group was signifieant(P ＜ 0.01 ). Conclusion Neurotropism in collateral spouting after end-to-side neurorrhaphy is not significant.

Uso da cola de fibrina na anastomose nervosa: estudo comparativo experimental em ratos / Fibrin glue use in nervous anastomosis: an experimental comparative study in rat

Há muitos anos a técnica, dita convencional, para aproximação dos cotos afastados do nervo lesado, é realizada com pontos de fios microcirúrgicos. Recentemente, a cola de fibrina tem sido utilizada para essa finalidade. O objetivo deste estudo é verificar a reinervação obtida através da sua aplicação experimental. Utilizou-se uma amostra de 35 ratos divididos em 3 grupos (grupo A: cola de fibrina; grupo B: cola e sutura; Grupo C: sutura). Após 90 dias, o nervo isquiático foi retirado e avaliado através da mensuração da espessura média da bainha de mielina das fibras regeneradas e da medição do número de axônios regenerados em um milímetro quadrado, visando a identificar o potencial de reinervação. Espessura média da bainha de mielina, em micras, foi: grupo A: 0,4417; grupo B: 0,5452; grupo C: 0,8510. O número médio de axônios reinervados por milímetro quadrado foi: grupo A: 12,95; grupo B: 25,07; grupo C: 21,17. Após a avaliação dos resultados verificou-se que o grupo que utilizou cola de fibrina apresentou menor reinervação quando comparado aos outros (AU)

For many years the so-called conventional technique to approach the separated stumps of an injured nerve has been performed using microsurgical thread stitches. Recently, fibrin glue began to be used for this purpose. The objective of this study is to look at the reinnervation achieved by using it experimentally. A sample of 35 rats was used, divided into 3 groups (Group A: Fibrin Glue; Group B: Glue and Suture; Group C: Suture). After 90 days the sciatic nerve was removed and evaluated by measuring the mean thickness of the myelin sheath of regenerated fibers and the number of axons regenerated in a square millimeter, aiming at identifying the potential for reinnervation. The mean thickness of the myelin sheath in micra was: Group A 0.4417; Group B 0.5452; Group C 0.8510. The mean number of axons reinnervated per square millimeter was: Group A 12.95; Group B 25.07; Group C 21.17. After the results were evaluated, it was found that the group using fibrin glue presented the least reinnervation as compared to the others (AU)