Article
Possibility of a 3-way-conduit (isogeneic trifurcated aorta) for facial-nerve reconstruction in an animal model
Die Möglichkeit eines Drei-Wege-Interponats (isogene Aortentrifurkation) zur Rekonstruktion des Nervus facialis in einem Tiermodell
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Published: | May 8, 2019 |
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Objective: The “post-paralytic syndrome” after facial nerve reconstruction has been attributed to (i) malfunctioning axonal guidance at the fascicular (branches) level, (ii) supernumerary collateral branches from transected axons, and (iii) intensive intramuscular terminal sprouting of regenerating axons which causes poly-innervation of the neuromuscular junctions (NMJ). The first two reasons were managed by an innovative approach which should supply the re-growing axons optimal conditions to elongate and selectively re-innervate their original muscle groups.
Methods: From ninety-six adult female inbred rats 24 were used to harvest the abdominal aorta and its 3 branches, which was used as a 3-way-conduit. The remaining 72 animals were divided into 6 groups, each of 12 rats. The transected facial nerve trunk was inserted into a 3-way-conduit (from isogeneic rat abdominal aorta) which should “lead” the re-growing facial axons to the three main branches of the facial nerve (zygomatic, buccal and marginal mandibular branches). The effect of this method was tested also on hypoglossal axons after hypoglossal-facial anastomosis (HFA). Coaptation (classic) FFA (facial-facial anastomosis) and HFA served as controls.
Results: When compared to their coaptation (classic) alternatives, both types of 3-way-conduit operations (FFA and HFA) promoted a trend for reduction in the proportion of double-labelled (or triple-labelled) perikarya (indicative of collateral axonal branching). In contrast, poly-innervation of NMJ in the levator labii superioris muscle was increased and vibrissal (whisking) function worsened.
Conclusion: The use of 3-way-conduit provides no advantages to classic coaptation. Should the latter be impossible (too large interstump defect), this type of reconstruction may be applied. We think that the option of inserting 3 separate interpositional nerve grafts should be tested.