Objective: To evaluate the changes of maximum fibrillation potential amplitude and root- mean-square (RMS) value of denervation potential after nerve injury using power spectrum analysis.

Methods: The sciatic nerve was transected in 8 rats, and was compressed in 6 rats. Denervation potentials were collected in gastrocnemius using monopolar needle weekly after nerve injury. The change of RMS value of 1 second epoch of denervation potentials with time was evaluated and compared with the change of maximun fibrillation potential amplitude.

Results: In nerve-transected rat, the RMS value declined linearly with time after injury. On the contrary, the amplitude of fibrillation potentials declined much rapidly during first 3 weeks. In nerve-compressed rat, both the RMS value and amplitude of fibrillation potential increased for 2 weeks after injury, and declined thereafter. As the result of simple regression analysis, the changes of RMS value correlated better than changes of fibrillation amplitude in all 8 nerve-transected rat.

Conclusion: The RMS value of denervation potentials correlated well with time after nerve injury in animal experiments. Measurement of the RMS value might be helpful to evaluate the time after peripheral nerve injury, but long-term human data should be essential for clinical application.

Objective: To compare the effects and side effects of chemodenervation according to the neurolytic agents, injection techniques and treatment indications.

Method: One hundred and seventy three cases of chmodenervation were reviewed. They were classified into three groups(phenol, b otulinum toxin, mixed) according to the neurolytic agents and into three groups(nerve trunk block, motor point block, both) according to the injection technique and nine gruoups(cervical dystonia, elbow flexor spasticity, wrist and hand spasticity, hip adductor spasticity, stiff knee gait, ankle plantar flexor spasticity, sustained ankle clonus, rear foot varus, toe clawing) according to the treatment indications. The rate of suboptimal results and side effects was descriptively measured.

Results: 1) The suboptimal results were observed in 19% of phenol blocks and 17% of Botulinum toxin injections. But the side effects were more frequently observed in phenol blocks(25%) than Botulinum toxin injections(2%).

2) In terms of phenol injection techniques, a nerve trunk injection was more successful(88%) than a motor point injection(69%). In case of simultaneous injections into the nerve trunk and motor point, the effects were very promising(100%). But the side effects were more frequently observed in the nerve trunk injections(26%) than the motor point injections(12%).

3) In terms of treatment indications, suboptimal results were observed in 44% of stiff knee gaits, 38% of cervical dystonias and 27% of toe clawing cases. Side effects were observed in 33% of toe clawing cases, 25% of sustained ankle clonus cases and 21% of elbow flexor spasticity cases.

Conclusion: The suboptimal results were slightly higher in botolinum toxin injections than in phenol blocks. The side effects were more frequently observed in phenol blocks than in botulinum toxin injections.