Article

OBJECTIVE: To determine the effects of botulinum neurotoxin type A (BTX-A)
dilution and endplate-targeting in spastic elbow flexors. DESIGN: Double blind
randomized controlled trial; 4-month follow-up after a 160-unit injection of
BTX-A into spastic biceps brachii (4 sites). Randomization into: group 1: 100
mouse units (MU)/mL dilution, 0.4cc/site, 4-quadrant injection; group 2: 100MU/mL
dilution, 0.4cc/site, 4 sites along endplate band; group 3: 20MU/mL dilution,
2cc/site, 4-quadrant injection (n=7 per group). SETTING: Institutional tertiary
care ambulatory clinic. PARTICIPANTS: Referred sample of 21 adults with spastic
hemiparesis. No participant withdrew due to adverse effects. A 160-unit injection of BTX-A of different dilutions and locations into biceps
brachii. MAIN OUTCOME MEASURES: Primary: agonist and antagonist (cocontraction)
mean rectified voltage (MRV) of elbow flexors/extensors during maximal isometric
flexion/extension; secondary: maximal voluntary power of elbow flexion/extension;
spasticity angle and grade in elbow flexors/extensors (Tardieu Scale); active
range of elbow extension/flexion. RESULTS: BTX-A injection overall reduced
agonist flexor MRV (-47.5%, P<0.0001), antagonist flexor MRV (-12%, P=.037),
antagonist extensor MRV (-19%, P<.01), flexion maximal voluntary power (-33%,
P<.001), elbow flexor spasticity angle (-30%, P<.001) and grade (-17%, P=.03),
and increased extension maximal voluntary power (24%, P=.037) and active range of
elbow extension (5.5%, 8 degrees , P=.002). Agonist and antagonist flexor MRV
reductions in group 3 (-81% and -31%) were greater than in groups 1 and 2,
whereas increase in active range of elbow extension was greater in group 2 (10%)
than in groups 1 and 3 (P<.05, analysis of covariance [ANCOVA]). Elbow flexor
spasticity was significantly reduced in groups 2 and 3 only (P<.05, ANCOVA).
CONCLUSIONS: In spastic biceps, high-volume or endplate-targeted BTX-A injections
achieve greater neuromuscular blockade, cocontraction and spasticity reduction,
and active range of elbow extension improvement, than low volume, nontargeted
injections.

Langue : ANGLAIS

Tiré à part : OUI