Radiological anatomy of the obturator nerve and its articular branches: basis to develop a method of radiofrequency denervation for hip joint pain.
OBJECTIVE
A previous study of radiofrequency neurotomy of the articular branches of the obturator nerve for hip joint pain produced modest results. Based on an anatomical and radiological study, we sought to define a potentially more effective radiofrequency method.


METHODS
Ten cadavers were studied, four of them bilaterally. The obturator nerve and its articular branches were marked by wires. Their radiological relationship to the bone structures on fluoroscopy was imaged and analyzed. A magnetic resonance imaging (MRI) study was undertaken on 20 patients to determine the structures that would be encountered by the radiofrequency electrode during different possible percutaneous approaches.


RESULTS
The articular branches of the obturator nerve vary in location over a wide area. The previously described method of denervating the hip joint did not take this variation into account. Moreover, it approached the nerves perpendicularly. Because optimal coagulation requires electrodes to lie parallel to the nerves, a perpendicular approach probably produced only a minimal lesion. In addition, MRI demonstrated that a perpendicular approach is likely to puncture femoral vessels. Vessel puncture can be avoided if an oblique pass is used. Such an approach minimizes the angle between the target nerves and the electrode, and increases the likelihood of the nerve being captured by the lesion made. Multiple lesions need to be made in order to accommodate the variability in location of the articular nerves.


CONCLUSIONS
The method that we described has the potential to produce complete and reliable nerve coagulation. Moreover, it minimizes the risk of penetrating the great vessels. The efficacy of this approach should be tested in clinical trials.
Locher
Stephan
S
Department of Anesthesiology, Division of Pain Therapy, University Hospital of Bern, Bern, Switzerland.
Burmeister
Helge
H
Böhlen
Thomas
T
Eichenberger
Urs
U
Stoupis
Christophoros
C
Moriggl
Bernhard
B
Siebenrock
Klaus
K
Curatolo
Michele
M
D002102:Cadaver; D003714:Denervation / Q000379:methods*; D005260:Female; D006621:Hip Joint / Q000033:anatomy & histology / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009776:Obturator Nerve / Q000033:anatomy & histology / Q000528:radiation effects; D010146:Pain / Q000473:pathology; D059408:Pain Management; D000078702:Radiofrequency Therapy