Comparison of Surface and Ultrasound Localization to Identify Forearm Flexor Muscles for Botulinum Toxin Injections
Received 12 November 2009; accepted 4 May 2010.
Objective
To determine if ultrasound (US) localization is equivalent to surface landmark localization to identify botulinum toxin injection targets for forearm muscle spasticity.
Design
Observational.
Setting
Outpatient spasticity clinic in a tertiary care center.
Subjects
Eighteen patients with upper-extremity flexor spasticity that interferes with function were included. Individuals with severe fixed contractures or traumatic injury of the involved forearm were excluded.
Methods
Flexor pollicis longus, flexor carpi radialis, pronator teres, and flexor digitorum superficialis (FDS) were identified by 2 separate localization techniques: the method of Delagi et al for flexor carpi radialis, pronator teres, and flexor pollicis longus; and a surface landmark technique by Bickerton et al to identify the 4 muscle bellies of FDS. Proximodistal and lateral (radial) coordinates were recorded relative to a landmark line from the medial epicondyle to pisiform bone, and percentage of landmark line distance was calculated. After surface measurements were collected, the best point for injection was determined by using real-time US with a 12-MHz linear transducer. US measurements were recorded by using the same landmark line system.
Results
Localization techniques were compared by using the Wilcoxon signed rank test. One-sample t-tests compared surface-mapped lateral coordinates to US-derived lateral coordinates with controls for multiple testing. Significant differences were observed between surface and US proximodistal and lateral coordinates for several flexor muscles.
Conclusions
US should be considered as an adjunct for localization in patients with upper-limb spasticity. US can improve accuracy of toxin placement and help to avoid injection into vascular and nerve structures.
aDepartment of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA⁎
bDepartment of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Kaufmann Building, Suite 201, 3471 Fifth Ave, Pittsburgh, PA 15213†
cDepartment of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA‡
dDepartment of Physical Medicine and Rehabilitation, and Department of Occupational Therapy, University of Pittsburgh School of Medicine, Pittsburgh, PA§
eDepartment of Physical Medicine and Rehabilitation, and Department of Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA¶
fDepartment of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA∥
Address correspondence to: M.C.M.
Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org
ABSTRACT