Musculoskeletal Development

Understanding Mechanobiological Effects of Peripheral Nerve Injury on Developing Bone and Muscle

Collaboration with Dr. Katherine Saul, Mechanical & Aerospace Engineering, NC State

Brachial Plexus Birth Injury (BPBI), a peripheral nerve injury that affects 1 in 1,000 births annually, causes impaired function of the neonatal upper limb. Despite physical therapy and surgical interventions, the resulting denervation of muscle following injury often causes gross morphological changes in the glenohumeral joint, presenting as osseous (e.g. glenoid retroversion, humeral head subluxation) and postural deformities (e.g. internal shoulder rotation contracture).

Effects to bone due to altered musculoskeletal loading following nerve injury requires an in-depth understanding of changes in bone mineralization and microstructure in developing joints, which is currently not well understood. We use a rat model to determine BPBI-related changes in bone structure and metabolism in the proximal humerus and distal scapula during development using micro-computed tomography and histology. While the etiology of osseous deformity in BPBI remains unclear, understanding changes in bone microstructure and metabolism resulting from injury may present a foundation for understanding the progression of deformity and offer targets for interventions and treatments.

Selected Publications and Presentations:

• Fawcett EB*, Bosh KB*, Saul KR, Cole JH (2025). Changes in glenohumeral musculoskeletal development following brachial plexus birth injury. Journal of Orthopaedic Research. In press. DOI: 10.1002/jor.26104. PMID: 40483597. *co-first authors
• Dunkley BK, Bosh KB, Saul KR, Cole JH. “Development of excess extracellular collagen in biceps, subscapularis, and supraspinatus muscles following brachial plexus birth injury.” National Conference on Undergraduate Research, Pittsburgh, PA, Apr 7-9, 2025. (talk)
• Bosh KB, Howes CLE, Fawcett EB, Saul KR, Cole JH. “Alterations in trabecular microstructure following brachial plexus birth injury.” Orthopaedic Research Society Annual Meeting, Phoenix, AZ, Feb 7-11, 2025. (poster)
• Doshi RM, Reid MY, Dixit NN, Fawcett EB, Cole JH, Saul KR (2022). Location of brachial plexus birth injury affects functional outcomes in a rat model. Journal of Orthopaedic Research 40(6):1281-1292. DOI: 10.1002/jor.25173. PMCID: PMC8873217.
• Fawcett EB*, McCormick CM*, Murray AF, Crouch DL, Saul KR, Cole JH. Characterizing trabecular bone properties near the glenohumeral joint in a rat model of brachial plexus birth injury. bioRxiv preprint.  DOI: 10.1101/2020.02.26.967224. Submitted to Annals of Biomedical Engineering. *co-first authors
• Bosh KB, Potts JR, Danelson KA, Saul KR, Cole JH. “Early alterations in forelimb grip strength and gait following brachial plexus birth injury” North American Congress on Biomechanics, Aug 21-25, 2022 (poster)
• Tushak SK*, Tamburro MK*, Fawcett EB, Merritt LE, Saul KR, Cole JH. Forelimb disuse impairs glenohumeral muscle development in growing rats. bioRxiv preprint. [DOI: 10.1101/967273]. *co-first authors
• Dixit NN, McCormick CM, Cole JH, Saul KR (2021). Influence of brachial plexus birth injury location on glenohumeral joint morphology. The Journal of Hand Surgery 46(6):512.e1-512.e9. DOI: 10.1016/j.jhsa.2020.10.019. PMID: 33358583.
• Dixit NN, McCormick CM, Warren E, Cole JH, Saul KR (2021). Preganglionic and postganglionic brachial plexus birth injury effects on shoulder muscle growth. The Journal of Hand Surgery 46(2): 146.e1-146.e9. DOI: 10.1016/j.jhsa.2020.07.017. PMID: 32919794.
• Dixit NN, McFarland DC, Fisher MB, Cole JH, Saul KR (2020). Integrated iterative musculoskeletal modeling predicts bone morphology following brachial plexus birth injury (BPBI). Journal of Biomechanics 103:109658. DOI: 10.1016/j.jbiomech.2020.109658. PMID: 32089271.

This work was funded by the National Institutes of Health (R01HD101406) and the NC State Office of Undergraduate Research.