Development of Diffusion MRI and Tractography Technique for the Detection of Nerve Lesions in Brachial Plexus Injuries

Development of Diffusion MRI and Tractography Technique for the Detection of Nerve Lesions in Brachial Plexus Injuries: Feasibility Study

The objective of this prospective study is to contribute to improving the management of patients with obstetric brachial plexus palsy.

The main objective is the characterization of the microstructure by diffusion MRI in patients with a history of unoperated obstetrical brachial plexus palsy.

The brachial plexus is a collection of nerve fibers that provides all sensory and motor functions of the entire upper limb. Its anatomy is particularly complex.

Obstetric brachial plexus palsy (OBP) is defined as flaccid paralysis of the upper limb, occurring at birth, related to forceful manipulation of the fetus for its delivery. This neonatal condition is not uncommon.

While most cases of OBP appear to recover spontaneously, children with incomplete recovery may have significant functional limitations related to muscle weakness, more or less associated with soft tissue retractions. Muscle weakness will induce an imbalance that can affect bone growth and joint development.

Simple stretching or neurapraxia almost always progresses spontaneously and favorably. Avulsion injuries, on the other hand, cannot heal spontaneously and therefore require surgery to restore upper limb function. The aim of this study is that DTI (Diffusion Tensor Imaging) imaging of the brachial plexus allows access to the entire brachial plexus in order to establish a lesion assessment and a powerful tool to aid in the decision for surgical exploration.

To date, there is no standard imaging technique for exploring the brachial plexus.

Diffusion tensor imaging is a new acquisition technique that tracks the movement of water molecules in all three spatial planes.

Tractography, or fiber tracking, is an acquisition and analysis technique performed using diffusion tensor imaging (DTI) MRI data.

An MRI protocol has been developed for analyzing the brachial plexus based on pilot MRI scans performed at the Brain and Spine Institute. Subjects selected for this study will undergo MRI scans using different sequences from this protocol. Image processing and tractography sequences will allow for precise analysis of the function and structure of the brachial plexus nerves and characterization of lesions in affected subjects compared to the unaffected contralateral side. The hypothesis of this research is that DTI imaging of the brachial plexus will allow a better understanding of POPB by establishing a precise lesion assessment in association with clinical data.

This is a single-center, non-randomized feasibility study involving MRI imaging analyses and requiring no changes to the patient's usual care.

Imaging data from each subject will be analyzed and statistically compared. Each patient will serve as their own control (comparison between the healthy and pathological plexus).

Imaging data from each subject can be analyzed and statistically compared.

Inclusion Criteria:

• Patients aged 14 to 30 years
• Consulted by the Orthopedics Department at Armand Trousseau Hospital
• Diagnosed and monitored by Armand Trousseau Hospital for obstetrical brachial plexus palsy (OBBP)
• Having a single, unoperated lesion (lesions are very different and only exceptionally affect all the roots bilaterally).
• Not suffering from bone or neurological pathology unrelated to OBP
• Patients affiliated with or entitled to a social security scheme
• Patients who have received informed information and have signed, with the investigator, a consent form to participate in the study
• Parents/legal guardians who have received informed information and have co-signed, with the investigator, a consent form to participate in the study, for minor patients

Exclusion Criteria:

• History of rheumatoid pathologies, constitutional bone diseases, past or current pathologies affecting the arm or neck unrelated to the obstetric brachial plexus, any history of neoplasia or radiographic appearance consistent with a neoplastic fracture
• Current pregnancy
• Inability to perform the MRI examination (presence of a contraindication, incapacitating pain, or claustrophobia)
• Large tattoo present in the area of interest (artifacts)
• Patients deprived of liberty, or under guardianship/curatorship
• Patients receiving medical assistance (AME)