Comparison of microsuture, interpositional nerve graft, and laser solder weld repair of the rat inferior alveolar nerve

Experimental Cranial Nerve Models in the Rat

BACKGROUND

 The intricacies of nerve regeneration following injury have prompted increased research efforts in recent years, with a primary focus on elucidating regeneration mechanisms and exploring various surgical techniques. While many experimental animals have been used for these investigations, the rat continues to remain the most widely used model due to its cost-effectiveness, accessibility, and resilience against diseases and surgical/anesthetic complications. A comprehensive evaluation of all the experimental rat models available in this context is currently lacking.

METHODS

 We summarize rat models of cranial nerves while furnishing descriptions of the intricacies of achieving optimal exposure.

RESULTS

 This review article provides an examination of the technical exposure, potential applications, and the advantages and disadvantages inherent to each cranial nerve model.

CONCLUSION

 Specifically in the context of cranial nerve injury, numerous studies have utilized different surgical techniques to expose and investigate the cranial nerves in the rat.

Dexamethasone and concentrated growth factors on peripheral nerve injury: A clinic-relevant animal study

BACKGROUND

Mandibular nerve injury is a common clinical condition that affects clinicians' management and patients' quality of life. In the literature, there are various effective treatments available. The primary purpose of this study was to determine and compare the effects of dexamethasone and concentrated growth factor (CGF) on regeneration in patients with nerve trauma that mimics clinical situations.

METHODS

In this study, 36 rats were divided into 3 groups: the control, dexamethasone and CGF groups. The inferior alveolar nerve was traumatized through the extraction socket after mandibular molar tooth extraction in each group.

RESULTS

The data showed a decrease in the control (4.5-4), dexamethasone (3-2), and CGF (4-3) groups according to the histological injury severity score (HISS) results. Compared with those in the other groups, the number of degenerative axons and edematous areas observed via histological examination were significantly lower in the CGF groups. Similarly, compared with those in the control group, the nNOS and Neurofilament-H positivity in the dexamethasone group on the 30th day (2,2 to 1,1 respectively) was significantly lower. The positivity of all the primary antibodies in the 3rd and 30th day CGF groups was significant compared than that in the dexamethasone 30th day group.

CONCLUSION

According to the results of the analysis of the immunohistopathological and HISS data, the CGF groups exhibited greater regeneration than did the dexamethasone groups.

Nerve Repair and Orthodromic and Antidromic Nerve Grafts: An Experimental Comparative Study in Rabbit

Purpose

Although many surgeons have anecdotally described reversing the polarity of the autograft with the intent of improving regeneration, the optimal orientation of the autogenous nerve graft remains controversial. The aim of this study was to compare (1) the outcomes of orthodromic and antidromic nerve grafts to clarify the effect of nerve graft polarity and (2) the outcome of either form of nerve grafts with that of nerve repair.

Methods

In 14 of the 26 rabbits used in this study, a 1 cm defect was made in the tibial nerve. An orthodromic nerve graft on one side and an antidromic nerve graft on the other were performed using a 1.2 cm long segment of the peroneal nerve. In the remaining 12 rabbits, the tibial nerve was transected completely and then repaired microscopically on one side but left untreated on the other. Electrophysiologic studies were performed in all animals at 8 weeks after surgery, and the sciatic nerves were harvested.

Results

Compound motor action potential was visible in all rabbits treated by nerve repair but in only half of the rabbits treated by nerve graft. There was no significant difference in the compound motor action potential, nerve conduction velocity, or total number of axons between the orthodromic and antidromic nerve graft groups. However, in both groups, the outcome was significantly poorer than that of the nerve repair group.

Conclusion

There was no significant difference by electromyographic or histologic evaluation between orthodromic and antidromic nerve grafts. Direct nerve repair with moderate tension may be a more effective treatment than nerve grafting.