Experimental nerve transfer model in the rat forelimb

Abstract

SummaryBackgroundNerve transfers are a powerful tool in extremity reconstruction, but the neurophysiological effects have not been adequately investigated. As 81 % of nerve injuries and most nerve transfers occur in the upper extremity with its own neurophysiological properties, the standard rat hindlimb model may not be optimal in this paradigm. Here we present an experimental rat forelimb model to investigate nerve transfers.MethodsIn ten male Sprague-Dawley rats, the ulnar nerve was transferred to the motor branch of long head of the biceps. Sham surgery was performed in five animals (exposure/closure). After 12 weeks of regeneration, muscle force and Bertelli test were performed and evaluated.ResultsThe nerve transfer successfully reinnervated the long head of the biceps in all animals, as indicated by muscle force and behavioral outcome. No aberrant reinnervation occurred from the original motor source. Muscle force was 2,68 N ± 0.35 for the nerve transfer group and 2,85 N ± 0.39 for the sham group, which was not statically different (p = 0.436). The procedure led to minor functional deficits due to the loss of ulnar nerve function; this, however, could not be quantified with any of the presented measures.ConclusionThe above-described rat model demonstrated a constant anatomy, suitable for nerve transfers that are accessible to standard neuromuscular analyses and behavioral testing. This model allows the study of both neurophysiologic properties and cognitive motor function after nerve transfers in the upper extremity.

Peripheral nerve transfers change target muscle structure and function

“…Nerve transfers were performed as previously described (Fig. 1A) ( 31 ). In brief, an incision was made on the upper extremity from the pectoral muscle to the medial epicondyle of the humerus.…”

Experimental Testing of Bionic Peripheral Nerve and Muscle Interfaces: Animal Model Considerations

“…Here, the brachial plexus offers a variety of nerves. For a detailed description and surgical approach we refer to our previous work (Bergmeister et al, 2016a). We have also recently shown the feasibility of using multichannel EMG electrodes in a rat TMR model.…”

Broadband Prosthetic Interfaces: Combining Nerve Transfers and Implantable Multichannel EMG Technology to Decode Spinal Motor Neuron Activity

“…Re-routing these fibers to reinnervate residual stump muscles re-establishes motor unit function (Bergmeister K. et al, 2016). The hyper-reinnervation of a single muscle by a multifascicular nerve with a greater fiber input will lead to a higher number of functional motor units in the targeted muscle with respect to its natural innervation (Kuiken et al, 1995; Kapelner et al, 2016).…”

“…Recent neuro-histological analyses of peripheral nerves indicate that an average of approximately 25,000 efferent nerve fibers control the upper extremity function and thereof only approximately 1,800 motor nerve fibers ultimately control intrinsic hand function (Gesslbauer et al, in review). Re-routing these fibers to reinnervate residual stump muscles re-establishes motor unit function (Bergmeister K. et al, 2016 ). The hyper-reinnervation of a single muscle by a multifascicular nerve with a greater fiber input will lead to a higher number of functional motor units in the targeted muscle with respect to its natural innervation (Kuiken et al, 1995 ; Kapelner et al, 2016 ).…”