Tourniquet Paralysis may Reflect Injury of Muscle Spindles

Objective: Knee operation using pneumatic tourniquet may cause weakness of the quadriceps femoris muscle. A patient with a paresis of the quadriceps femoris muscle for two months postoperatively was studied. Methods: ENMG and lumbar magnetic stimulation (MEP) follow-up.Results: There was no distinct lesion of the motor axons of the femoral or other nerves in ENMG or MEP six weeks postoperatively. After a follow-up of eight months, the paresis was subsided and a complete recovery took place in two years.Conclusion: High pressure of the tourniquet may injure muscle spindles. Decreased Ia-afferent activity may severely inhibit voluntary motor effort.