[Experimental study of radiofrequency thermocoagulation and applied anatomy of posterior rami of lumbar nerves].
OBJECTIVE
To determine points of radiofrequency thermocoagulation of the posterior rami of the lumbar nerves and to choose an effective temperature at which the conduction of painful impulse can be blocked.


METHODS
The posterior rami of the lumbar nerves were dissected in 15 corpses of adults. The ultrastructure of nerve fibres, changes of sensary conduction velocity (SCV) and the waveform of the unmedullated fibres which conduct painful impulse (c wave) were observed after the sciatic nerves of rabbits were coagulated at various temperatures (60 degrees C, 70 degrees C, 80 degrees C, 90 degrees C).


RESULTS
"Transverse Process Root Area" and "Transverse Process Point" can be regarded as primary marks of thermocoagulation of the posterior rami of the lumbar nerves. Stimulation of square-wave can make the location more accurate. While the temperature of thermocoagulation reached 80 degrees C, none of painful afferent nerve fibres survived.


CONCLUSIONS
With accurate location and good control of temperature, radiofrequency thermocoagulation will be an effective therapy for the patients suffering from pain resulted from pathological changes of the posterior rami of the lumbar nerves.
Yao
M
M
Department of Orthopaedics, 2nd Affiliated Hospital, Harbin Medical University, Harbin 150086.
Dong
D
D
Liu
Q
Q
Jiang
Y
Y
Sun
C
C
Li
Z
Z
Zhu
J
J
Zhang
J
J
Song
S
S
D000328:Adult; D000818:Animals; D004564:Electrocoagulation / Q000379:methods*; D006801:Humans; D017116:Low Back Pain / Q000601:surgery*; D009412:Nerve Fibers / Q000648:ultrastructure; D009431:Neural Conduction; D011817:Rabbits; D012584:Sciatic Nerve / Q000502:physiology*; D013127:Spinal Nerves / Q000033:anatomy & histology*; D013696:Temperature