Tensile strength of healing peripheral nerves.
Although the time required for a nerve to gain sufficient strength to withstand normal physiologic forces of joint motion is unknown, typically nerve repairs are protected up to 3 weeks postoperatively. The authors investigated the mechanical strength of a nerve repair as a function of time. Fifty adult Sprague-Dawley rats underwent sciatic nerve division and repair, and were sacrificed in groups of 10 at 0, 1, 2, 4, and 8 weeks. Repaired nerves were then mechanically loaded at 5 mm/min to failure. Gapping across the repair site was captured on high-resolution video. The contralateral sciatic nerve served as a control. A significant increase in tensile strength was gained between 0 and 1 week and between 2 and 4 weeks. Healing nerves achieved 63 percent of the strength of the control by 8 weeks. Controls showed no gain in strength over the testing period. Gapping occurred at lower forces at all time increments. From 0 to 1 week, a significant increase in load necessary to produce gapping was found, which did not increase significantly again until 8 weeks. These results may have implications for postoperative rehabilitation protocols in patients with nerve injuries.
Temple
C L F
CL
Division of Plastic Surgery, University of Western Ontario.
Ross
D C
DC
Dunning
C E
CE
Johnson
J A
JA
King
G J W
GJ
D000818:Animals; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000601:surgery*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries / Q000601:surgery; D013718:Tensile Strength; D013997:Time Factors; D014945:Wound Healing / Q000502:physiology*