Alleviated tension at the repair site enhances functional regeneration: the effect of full range of motion mobilization on the regeneration of peripheral nerves--histologic, electrophysiologic, and functional results in a rat model.
BACKGROUND
In the clinical management of combined tendon and nerve injuries, competing treatment strategies are well known. The effect of mobilization on the functional regeneration of peripheral nerves remains controversial. This study sought to determine the effect of full range of motion mobilization on nerve repair by using tubular segmental nerve splinting to block movement, and thereby variable tension, at the nerve repair site.


METHODS
In 96 rats, the right sciatic nerve was transected midthigh and coapted immediately microsurgically. The groups used in the study were as follows: group N, epineural nerve repair; group T, segmental tubular nerve splinting with fixed in situ tension at the nerve suture site,allowing segmental movement only; group TN, segmental tubular nerve splinting with alleviated in situ tension at the nerve suture site, allowing segmental movement only; and group TM, segmental tubular nerve splinting without fixed in situ tension at the nerve suture site, allowing movement of the nerve suture site. Full range of motion of the lower limbs was ensured by passive motion of hind limbs once a week after functional testing. Blinded histologic, immunohistochemical, and electrophysiologic assessment and 12 postoperative weekly function tests were carried out.


RESULTS
Functional and electrophysiologic results were significantly better in group TN, by segmental tubular nerve splinting with alleviated in situ tension at the nerve repair site, mainly because of less scar formation and enhanced endoneural angiogenesis at the nerve suture segment.


CONCLUSIONS
Full range of motion mobilization may impede functional nerve recovery by significant endoneural collagenization and decreased angiogenesis at the nerve suture segment. Complete alleviation of in situ (pathophysiologic) tension at the nerve suture site seems to improve functional peripheral nerve regeneration.
Schmidhammer
Robert
R
Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Research Center for Traumatology of the AUVA, Donaueschingenstrasse 13, A-1200 Vienna, Austria. r.schmidhammer@a1.net
Zandieh
Shahin
S
Hopf
Rudolf
R
Mizner
Ingrid
I
Pelinka
Linda E
LE
Kroepfl
Albert
A
Redl
Heinz
H
D000818:Animals; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure; D004434:Early Ambulation; D006614:Hindlimb / Q000294:innervation; D008297:Male; D008866:Microsurgery / Q000379:methods*; D018919:Neovascularization, Physiologic; D009416:Nerve Regeneration / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D016059:Range of Motion, Articular / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D013165:Splints; D013536:Suture Techniques; D013718:Tensile Strength
D003094:Collagen