Brachial plexus birth palsy-associated shoulder deformity: a rat model study

J Hand Surg Am. 2008 Mar;33(3):308-12. doi: 10.1016/j.jhsa.2007.11.017.

Abstract

Purpose: Although recovery occurs in the majority of cases of brachial plexus birth palsy (BPBP), long-term shoulder disability is relatively common. The aim of this study was to establish an animal model to study BPBP-associated shoulder deformities.

Methods: A right-side C5, C6 root neurotomy was performed under the surgical microscope in 5-day-old Sprague-Dawley rats (N = 9). The contralateral side served as a control. The development of shoulder deformity and range of motion loss were followed longitudinally. Animals were killed 4 months after surgery. Both shoulders were harvested, decalcified, and transected in the axial plane for glenoid version measurement and shoulder histology.

Results: All animals developed shoulder internal rotation contracture within 4 weeks after the C5, C6 neurotomy. The average shoulder external rotation loss was 52 degrees +/- 7, 59 degrees +/- 10, and 82 degrees +/- 11 in comparison with the control side 1, 2, and 4 months after neurotomy, respectively. Glenoid version changed from 2 degrees +/- 2 of retroversion (left side) to 8 degrees +/- 3 of anteversion. Five shoulders were subluxated clinically with a pseudoglenoid formation observed radiographically. Histologic study demonstrated marked glenoid and humeral head deformities.

Conclusions: This neonatal rat model clearly demonstrated typical shoulder deformities similar to that resulting from Erb's palsy. This model can be useful in studying BPBP-associated shoulder deformities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Birth Injuries / physiopathology*
  • Brachial Plexus Neuropathies / physiopathology*
  • Contracture / physiopathology
  • Joint Deformities, Acquired / physiopathology*
  • Male
  • Models, Animal
  • Range of Motion, Articular / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Shoulder Joint / pathology*
  • Shoulder Joint / physiopathology*