Electromyographic findings after different selective neck dissections.
OBJECTIVE
The objective was to compare electrophysiologic investigations of the upper trapezius muscle (UT) after different selective neck dissections (SND) and analyze the differences between types of SND and the preservation and excision of the cervical nerves (the C2-4 rami of the cervical plexus).


METHODS
Retrospective study of 54 patients (average age, 65.1 +/- 9.6 yr, 45 males) with 70 SND.


METHODS
Patients underwent needle electromyography (EMG) of the UT by 4 months after surgery. The findings were rated according to the 5 point EMG scale system from 1 (total denervation: positive sharp wave or fibrillation potential at rest and electrical silence at voluntary contraction) to 5 (normal pattern).


RESULTS
The average EMG scale was 1.7 +/- 1.1, 58.6% for score 1 and only 5.7% for score 5. There was not a significant difference in the EMG scale between the types of SND, whereas the group in which the cervical nerves were excised was significantly lower than in that in which it was preserved. The average EMG scales in the former and latter were 1.5 +/- 0.8 and 2.0 +/- 1.3, 68.8%.


CONCLUSIONS
The study data confirm that complete or incomplete denervation of the UT was caused by axonal injury of the spinal accessory nerve, even though it was spared, because of traction of the nerve during neck dissection. Second, the excision of the C2 to 4 rami of the cervical plexus caused worse damage of the UT. It is suggested that it is important to preserve the cervical nerves to avoid denervation of the UT.
Tsuji
Tetsuya
T
Department of Rehabilitation Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan. cxa01423@nifty.com
Tanuma
Akira
A
Onitsuka
Tetsuro
T
Ebihara
Mitsuru
M
Iida
Yoshiyuki
Y
Kimura
Akio
A
Liu
Meigen
M
D000055:Accessory Nerve / Q000601:surgery; D061227:Accessory Nerve Injuries; D000200:Action Potentials / Q000502:physiology; D000368:Aged; D001369:Axons / Q000469:parasitology; D002572:Cervical Plexus / Q000503:physiopathology / Q000601:surgery; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009121:Muscle Denervation / Q000009:adverse effects; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009333:Neck / Q000294:innervation; D037981:Neck Dissection / Q000009:adverse effects / Q000379:methods