Effect of surgically guided axonal regrowth into a 3-way-conduit (isogeneic trifurcated aorta) on functional recovery after facial-nerve reconstruction: Experimental study in rats
Affiliations: [a] Department of Neurosurgery, University of Witten/Herdecke, Cologne Merheim Medical Center (CMMC), Cologne, Germany
| [b] Department of Prosthetic Dentistry, School of Dental and Oral Medicine, University of Cologne, Cologne, Germany
| [c] Department of Histology and Embryology, Aristotle University Thessaloniki, Greece
| [d] Department of Anatomy I, University of Cologne, Germany
| [e] Department of Anatomy, Akdeniz University Faculty of Medicine, Antalya, Turkey
Correspondence:
[*]
Corresponding author: Prof. Dr. Doychin N. Angelov, Department of Anatomy I, University of Cologne, Joseph-Stelzmann-Strasse 20, 50931 Cologne, Germany. Tel.: +49 221 478 5654; Fax: +49 221 478 87893; E-mail: [email protected].
Abstract: Background:The “post-paralytic syndrome” after facial nerve reconstruction has been attributed to (i) malfunctioning axonal guidance at the fascicular (branches) level, (ii) collateral branching of the transected axons at the lesion site, and (iii) intensive intramuscular terminal sprouting of regenerating axons which causes poly-innervation of the neuromuscular junctions (NMJ). Objective:The first two reasons were approached by an innovative technique which should provide the re-growing axons optimal conditions to elongate and selectively re-innervate their original muscle groups. Methods:The transected facial nerve trunk was inserted into a 3-way-conduit (from isogeneic rat abdominal aorta) which should “guide” the re-growing facial axons to the three main branches of the facial nerve (zygomatic, buccal and marginal mandibular). The effect of this method was tested also on hypoglossal axons after hypoglossal-facial anastomosis (HFA). Coaptational (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 collateral axonal branching (the proportion of double- or triple-labelled perikarya after retrograde tracing was slightly reduced). In contrast, poly-innervation of NMJ in the levator labii superioris muscle was increased and vibrissal (whisking) function was worsened. Conclusions:The use of 3-way-conduit provides no advantages to classic coaptation. Should the latter be impossible (too large interstump defects requiring too long interpositional nerve grafts), this type of reconstruction may be applied. (230 words)
