Applicability of Magnetic Resonance Imaging for Early Diagnosis of Common Peroneal Neuropathy

Abstract

Objective: This study aimed to assess the clinical applicability of magnetic resonance imaging (MRI) for the early diagnosis of common peroneal neuropathy (CPNe).Methods: Over three years, the authors have treated 58 patients with CPNe. All patients had clinical or neurophysiological confirmation of CPNe. Among them, 35 (60%) patients underwent axial knee MRI with a 1.5-Tesla scanner. These 35 patients were selected for study and were classified into three groups according to the time of examination after the occurrence of dropped foot―acute, subacute, and chronic onset groups. According to muscle appearances (normal, edematous change, and atrophy), we diagnosed them with CPNe, except for those with normal morphology. We evaluated the applicability of MRI in the diagnosis of CPNe compared to that of electromyography (EMG).Results: The 18, 11, and six cases were included in the acute, subacute, and chronic onset groups, respectively. In the acute onset group, three cases had normal muscle appearance, while 15 cases had edematous changes in the affected muscles. In the subacute onset group, eight cases had edematous changes, while three cases showed muscle atrophy. In the chronic onset group, six cases had muscle atrophy. CPNe could be diagnosed using MRI in about 91% (32/35) of all the cases. Excluding the chronologically chronic stage, diagnosis rate was approximately 89%(26/29) of all the cases. However, only in 27 cases (77%) denervation potentials were presented on EMG.Conclusion: According to our results, MRI is a helpful diagnostic modality, especially in the early stage of CPNe, and may lead to proper management.

The Common Peroneal Nerve Injuries

“…In chronic denervation, muscle atrophy and fatty infiltration demonstrate high signal changes on T1-weighted sequences associated with volume loss (Table 4, Fig. 3B, C) 8) .…”

“…3A). Muscle denervation results in enlargement of the intramuscular capillary bed, causing an increase in the muscle blood volume 8,11,19,33) . In addition, there is an increase in extracellular fluid within the denervated muscles.…”

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The common peroneal nerve (CPN) is crucial in maintaining a normal walking gait, and there are clinical situations where it is necessary to differentiate whether gait disturbance is caused by the central nervous system or spinal nerves 6,18,38) . In addition, the CPN is known as the most commonly injured peripheral nerve in the lower extremities due to its anatomical course 7,8,35,37) . In this review, we aim to describe the basic anatomy and function of the CPN and the common peroneal neuropathy (CPNe) caused by postures that are often encountered in the field of neurosurgery for the education of trainees, physician assistants, and neurosurgical fellows.

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