title: Epineurial Window Is More Efficient in Attracting Axons than Simple Coaptation in a Sutureless (Cyanoacrylate-Bound) Model of End-to-Side Nerve Repair in the Rat Upper Limb: Functional and Morphometric Evidences and Review of the Literature.
abstract: End-to-side nerve coaptation brings regenerating axons from the donor to the recipient nerve. Several techniques have been used to perform coaptation: microsurgical sutures with and without opening a window into the epi(peri)neurial connective tissue; among these, window techniques have been proven more effective in inducing axonal regeneration. The authors developed a sutureless model of end-to-side coaptation in the rat upper limb. In 19 adult Wistar rats, the median and the ulnar nerves of the left arm were approached from the axillary region, the median nerve transected and the proximal stump sutured to the pectoral muscle to prevent regeneration. Animals were then randomly divided in two experimental groups (7 animals each, 5 animals acting as control): Group 1: the distal stump of the transected median nerve was fixed to the ulnar nerve by applying cyanoacrylate solution; Group 2: a small epineurial window was opened into the epineurium of the ulnar nerve, caring to avoid damage to the nerve fibres; the distal stump of the transected median nerve was then fixed to the ulnar nerve by applying cyanoacrylate solution. The grasping test for functional evaluation was repeated every 10-11 weeks starting from week-15, up to the sacrifice (week 36). At week 36, the animals were sacrificed and the regenerated nerves harvested and processed for morphological investigations (high-resolution light microscopy as well as stereological and morphometrical analysis). This study shows that a) cyanoacrylate in end-to-side coaptation produces scarless axon regeneration without toxic effects; b) axonal regeneration and myelination occur even without opening an epineurial window, but c) the window is related to a larger number of regenerating fibres, especially myelinated and mature, and better functional outcomes.
authors.affiliation: Department of Biomedical Sciences and Morphological and Functional Images, University of Messina, Messina, Italy.
authors.forename: Igor
authors.initials: I
authors.lastname: Papalia
authors.affiliation: Department of Biomedical Sciences and Morphological and Functional Images, University of Messina, Messina, Italy.
authors.forename: Ludovico
authors.initials: L
authors.lastname: Magaudda
authors.affiliation: Department of Biomedical Sciences and Morphological and Functional Images, University of Messina, Messina, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Righi
authors.affiliation: Department of Clinical and Biological Sciences, University of Torino, Orbassano (Torino), Italy.|Neuroscience Institute of the "Cavalieri Ottolenghi" Foundation (NICO), University of Torino, Orbassano (Torino), Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Ronchi
authors.affiliation: Department of Clinical and Biological Sciences, University of Torino, Orbassano (Torino), Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Viano
authors.affiliation: Department of Clinical and Biological Sciences, University of Torino, Orbassano (Torino), Italy.|Neuroscience Institute of the "Cavalieri Ottolenghi" Foundation (NICO), University of Torino, Orbassano (Torino), Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Geuna
authors.affiliation: Department of Experimental and Clinical Surgical and Medical Specialties, University of Messina, Messina, Italy.
authors.forename: Michele Rosario
authors.initials: MR
authors.lastname: Colonna
mesh_terms: D000269:Adhesives / Q000494:pharmacology*; D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000502:physiology; D003487:Cyanoacrylates / Q000494:pharmacology*; D005260:Female; D008475:Median Nerve / Q000293:injuries / Q000601:surgery*; D009186:Myelin Sheath / Q000187:drug effects; D009411:Nerve Endings / Q000187:drug effects; D009416:Nerve Regeneration / Q000502:physiology; D019635:Neurosurgical Procedures / Q000295:instrumentation / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D016896:Treatment Outcome; D014459:Ulnar Nerve / Q000293:injuries / Q000601:surgery*; D034941:Upper Extremity / Q000294:innervation / Q000601:surgery
chemical_list: D000269:Adhesives; D003487:Cyanoacrylates