Botulinum Toxin Dilution and Endplate Targeting in Spasticity: A Double-Blind Controlled Study
Presented as an abstract to the American Neurological Association, October 14, 2002, New York.
Abstract
Gracies J-M, Lugassy M, Weisz DJ, Vecchio M, Flanagan S, Simpson DM. Botulinum toxin dilution and endplate targeting in spasticity: a double-blind controlled study.
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.
Intervention
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°, 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.
aDepartment of Neurology, Mount Sinai Medical Center, New York, NY
bDepartment of Neurosurgery, Mount Sinai Medical Center, New York, NY
cDepartment of Rehabilitation Medicine, Mount Sinai Medical Center, New York, NY
dDepartment of Neurology, Columbia Presbyterian Hospital, New York, NY
eU.O. Physical Medicine and Rehabilitation, Vittorio Emanuele Hospital, Catania, Italy
Correspondence to Jean-Michel Gracies, MD, Service de Médecine Physique et de Réadaptation, CHU Henri Mondor, 51, av du Maréchal De Lattre De Tassigny, 94010 Créteil, France
Supported by a research grant from Allergan, Inc.
A commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a financial benefit on the author or one or more of the authors.