Musculoskeletal growth in the upper arm in infants after obstetric brachial plexus lesions and its relation with

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Johanna M Ruoff1, Johannes A van der Sluijs, Willem J van Ouwerkerk

  • 1Department of Orthopaedic Surgery, VU University, Amsterdam, the Netherlands.

Developmental Medicine and Child Neurology
|August 1, 2012
PubMed

Insights

In infants with obstetric brachial plexus lesions (OBPL), denervation impacts upper arm muscle and bone growth. Muscle size in infants with OBPL does not predict elbow function, suggesting other factors influence later contractures.

Area of Science:

  • Pediatric Orthopedics
  • Neuroscience
  • Developmental Biology

Background:

  • Obstetric brachial plexus lesion (OBPL) can lead to denervation, affecting upper limb musculoskeletal development.
  • Reduced muscle growth in the affected arm is a known complication of OBPL.

Purpose of the Study:

  • To investigate the relationship between reduced upper arm muscle growth (flexors and extensors) and active elbow function in infants with OBPL.
  • To determine if humeral length is associated with muscle size and function in affected infants.

Main Methods:

  • Magnetic resonance imaging (MRI) was used to measure humeral length and muscle cross-sectional area (CSA) in 31 infants (<6 months) with unilateral OBPL.
  • Elbow function was assessed using the Gilbert score.

Main Results:

  • Infants with OBPL showed significantly smaller flexor and extensor CSAs (88% of unaffected side) and shorter humerus length (96% of unaffected side).
  • No correlation was found between reduced muscle size and residual muscle function.
  • Muscle hypertrophy was observed in 17 patients; humeral length was not related to muscle parameters.

Conclusions:

  • Denervation in OBPL affects muscle and bone growth differently.
  • In young infants with OBPL, muscle size is not a reliable predictor of muscle function.
  • Elbow flexion contractures later in childhood may not be solely due to flexor muscle mass dominance in infancy.
Abstract

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