Neuronal regeneration after application of radiofrequency energy to collagenous tissue is affected by limb immobilization: an in vivo animal study.
Despite widespread use of radiofrequency (RF)-shrinkage, there have been no studies on the influence of RF-energy on neural elements of collagenous tissue. The purpose of this study was to examine the effect of RF-shrinkage on neural structures of capsuloligamentous tissue and the recovery of neural elements under different postoperative treatment protocols. One patellar tendon of 46 New-Zealand-White rabbits was shrunk. Six rabbits were sacrificed immediately postoperative. Twenty rabbits were not immobilized, 10 were immobilized for 3 and 10 were immobilized for 6 weeks. A monoclonal antibody, specific against a neurofilament protein, was used to detect nerves and neural structures. Staining pattern of nerve fibres was significantly altered immediately postoperative. After 3 weeks the number of nerve fibres and bundles decreased significantly in immobilized and non-immobilized limbs. The loss of nerve fibres was significantly less in immobilized limbs. At 6 weeks the number of neural elements in immobilized limbs increased to the level of untreated control tissue. In non-immobilized limbs we found no recovery of neural elements 9 weeks postoperatively. At this time the number of nerve fibres and bundles was still significantly less compared to the untreated control limbs. RF-shrinkage causes significant alteration of neural elements. Under immobilization nerve fibres and bundles reach the level of normal untreated tissue. Careful rehabilitation is important after RF-shrinkage. Not only for biomechanical reasons, but also to allow the neural elements to recover, thermally modified tissue should be protected from normal physiologic loads.
Pötzl
W
W
Department of Orthopaedics, University Hospital Münster, Albert-Schweitzer Street 33, 48149, Germany. poetzl@uni-muenster.de
Kümpers
P
P
Szuwart
T
T
Filler
T
T
Marquardt
B
B
Steinbeck
J
J
D000818:Animals; D017115:Catheter Ablation; D006979:Hyperthermia, Induced; D007103:Immobilization; D007719:Knee Joint / Q000294:innervation / Q000601:surgery; D009412:Nerve Fibers / Q000502:physiology; D009416:Nerve Regeneration / Q000528:radiation effects*; D010329:Patella; D011183:Postoperative Complications / Q000517:prevention & control; D011434:Proprioception; D011817:Rabbits; D013710:Tendons / Q000294:innervation* / Q000601:surgery*