MR Neurography of Neuromas Related to Nerve Injury and Entrapment with Surgical Correlation

Abstract

SUMMARY: MR imaging of peripheral nerves has been described in relation to abnormalities such as nerve injury, entrapment, and neoplasm. Neuroma formation is a known response to peripheral nerve injury, and here we correlate the MRN appearance of postinjury neuroma formation with intraoperative findings. We also present the MR imaging features of surgical treatment with a synthetic nerve tube and nerve wrap on postoperative follow-up imaging.ABBREVIATIONS: MRN ϭ MR neurography; NIC ϭ neuroma in continuity; SPACE ϭ sampling perfection with application optimized contrasts by using different flip angle evolutions; SPAIR ϭ spectral adiabatic inversion recovery; STIR ϭ short tau inversion recovery P eripheral nerve injuries and entrapments may lead to formation of NIC, neuroma in completely severed nerves, and amputation neuroma. These lesions also demonstrate unique MRN appearances. This article presents MRN and surgical correlations of various posttraumatic neuromas with relevant case examples.

High-Resolution MR Neurography of Diffuse Peripheral Nerve Lesions

“…There have been multiple reports of MR imaging of peripheral nerves in compression and entrapment neuropathies. [1][2][3] However, there is a relative paucity of literature on the MRN appearance of diffuse peripheral nerve lesions. 4 These lesions seen on MR imaging present a diagnostic dilemma because a long list of pathologies could be causing them.…”

Closed Median Nerve Rupture from Elbow Trauma

“…Decision for surgical intervention in closed peripheral nerve injury is made based upon assessment of severity of injury and determination of potential for recovery. These injuries are categorized into neurapraxia (focal demyelination with no axonal disruption), axonotmesis (axon fiber disruption with connective tissue and myelin sheath preservation), and neurotmesis (full disruption of axonal continuity with partial to full disruption of the connective tissue and myelin sheath) [2]. Electrodiagnostic studies are used to distinguish these injuries and to help choose appropriate treatment.…”

Sciatic nerve injection injury

“…Magnetic resonance neurography shows increased signal intensity on T2-weighted images of injured nerves and can also help in the detection of postinjury neuroma formation. 34,35 Electromyography can be conducted on the extensor digitorum brevis, tibialis anterior, medial head of the gastrocnemius and the short head of the biceps femoris muscles using a concentric needle electrode. 25 It may show signs of acute denervation, presenting as a high insertional activity, positive spontaneous fibrillation, and sharp waves with low interference and recruitment in the affected muscles; alternatively it may show signs of chronic denervation with reinnervation, presenting with polyphasia, high amplitude, and a lowered interference pattern and recruitment in the affected muscles.…”