MRI for Detecting Root Avulsions in Traumatic Adult Brachial Plexus Injuries: A Systematic Review and Meta-Analysis of Diagnostic Accuracy

Abstract

T raumatic brachial plexus injuries affect 1% of patients involved in major trauma (1). Brachial plexus injuries may cause permanent disability (2-6), pain (6-8), psychologic morbidity (9,10), and reduced quality of life (2,4,11). Early reconstructive nerve surgery is associated with better functional recovery in the upper limb (2,3,11,12), which improves quality of life (4). Nerve reconstruction for patients with root avulsion(s) is a clinical priority for several reasons. After root avulsion, the cell bodies of motor neurons in the spinal cord recede (4,5,12,13), so the limb never reanimates spontaneously. Because reimplantation of avulsed roots yields no meaningful recovery (14-16), nerve transfers are performed, which significantly improves function (11,17-20). Nerve transfers are relatively minor and cost-effective procedures (21,22) with low morbidity (20,23-25). Furthermore, 95% of patients with traumatic brachial plexus injuries have neuropathic pain (6), and the evolving evidence suggests that early reconstructive nerve surgery reduces cortical reorganization and thus neuropathic or phantom limb pain (26-28). Therefore, correctly identifying patients with root avulsions is of paramount importance. MRI is the best noninvasive test for brachial plexus injuries (29). MRI is superior to nerve and muscle electrophysiology studies (30), US (31-34), and intraoperative somatosensory-evoked potentials (35). Currently, MRI

Diffusion tensor imaging of the roots of the brachial plexus: a systematic review and meta-analysis of normative values

“…Two review authors (RGW and AW) independently extracted data concerning the demographics, scanner, pulse sequence, pre-processing, tensorial reconstruction, measurement conditions and the outcomes of interest. The spinal nerve root was the unit of analysis [7] and root-level estimates of DTI parameters were extracted. Where data was missing or unclear, the corresponding author was contacted by email and/or phone and if no reply was received, 4 weeks later all authors were contacted in addition to re-contacting the corresponding author.…”

“…Magnetic resonance imaging (MRI) is generally considered the best non-invasive imaging modality for diagnosing various pathologies affecting the brachial plexus [1][2][3][4][5][6]. The roots of the brachial plexus are the most common site of injury [7] and typically, the status of the root dictates the prognosis and surgical reconstruction. Consequently, defining the health status of the roots is of paramount importance.…”

“…Consequently, defining the health status of the roots is of paramount importance. Whilst MRI is more accurate than electrophysiology [2,6], ultrasonography [3][4][5]8] and computed tomography myelography [9], the diagnostic performance of conventional cross-sectional MRI for assessing the spinal nerve roots remains suboptimal [7]. Consequently, there has been a surge of research into diffusion tensor imaging (DTI) which may provide additional valuable information.…”

Diffusion Tensor Imaging for Diagnosing Root Avulsions in Traumatic Adult Brachial Plexus Injuries: A Proof-of-Concept Study

“…Root avulsions are the most prevalent form of injury in traumatic BPI (6). Root avulsions are high-force injuries which affect all neural elements including the anterior horn cells (7), fibers in the transitional zone and free rootlets, all of which precludes re-implantation (8) and mandates reconstruction by nerve transfer.…”

“…Magnetic resonance imaging (MRI) is the best non-invasive test for diagnosing traumatic brachial plexus root avulsion(s); however, its accuracy (using conventional anatomical sequences) is modest at-best and importantly, MRI misclassifies ∼28% of incontinuity nerves as avulsed and fails to identify ∼7% of true avulsions (6). Further, there is no consensus (nor data) on the ideal time to scan such patients or which sequences are most accurate.…”