Abstract
Objectives
Traumatic brachial plexus injury causes severe functional impairment
of the arm. Elbow flexion is often affected. Nerve surgery or tendon
transfers provide the only means to obtain improved elbow flexion.
Unfortunately, the functionality of the arm often remains insufficient.
Stem cell therapy could potentially improve muscle strength and
avoid muscle-tendon transfer. This pilot study assesses the safety
and regenerative potential of autologous bone marrow-derived mononuclear
cell injection in partially denervated biceps.
Methods
Nine brachial plexus patients with insufficient elbow flexion
(i.e., partial denervation) received intramuscular escalating doses
of autologous bone marrow-derived mononuclear cells, combined with
tendon transfers. Effect parameters included biceps biopsies, motor
unit analysis on needle electromyography and computerised muscle tomography,
before and after cell therapy.
Results
No adverse effects in vital signs, bone marrow aspiration sites,
injection sites, or surgical wound were seen. After cell therapy
there was a 52% decrease in muscle fibrosis (p = 0.01), an 80% increase
in myofibre diameter (p = 0.007), a 50% increase in satellite cells
(p = 0.045) and an 83% increase in capillary-to-myofibre ratio (p
< 0.001) was shown. CT analysis demonstrated a 48% decrease in
mean muscle density (p = 0.009). Motor unit analysis showed a mean
increase of 36% in motor unit amplitude (p = 0.045), 22% increase
in duration (p = 0.005) and 29% increase in number of phases (p
= 0.002).
Conclusions
Mononuclear cell injection in partly denervated muscle of brachial
plexus patients is safe. The results suggest enhanced muscle reinnervation
and regeneration.
Cite this article: Bone Joint Res 2014;3:38–47.
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