Superficial peroneal nerve compression due to peroneus brevis muscle herniation

Abstract

Muscle hernias of the extremities most commonly occur in the leg, between the knee and ankle. Symptomatic muscle hernias in the leg are rare cause of chronic leg pain and neuropathy, and not routinely encountered in surgical practice. Although this condition is especially an esthetic problem, with palpable subcutaneous soft tissue mass, it can lead to spontaneous pain, cramp, local tenderness or potentially neuropathic symptoms. Moreover, among leg muscles involved in this process, peroneus brevis is less frequent than tibialis anterior. Magnetic Resonance Imaging is the method of choice in establishing the diagnosis. Symptomatic cases can be treated surgically in different ways, the preferred one is nerve releasing with fasciotomy. The purpose of this case report is to present the Magnetic Resonance findings of a superficial nerve compression due to a peroneus brevis muscle herniation.

Keywords: Fasciotomy; Magnetic Resonance Imaging; Muscle Hernia; Nerve Releasing; Peripheral Neuropathy.

Figure 1

The superficial peroneal nerve runs between the lateral (flag 2) and anterior muscle compartments, crossing the ankle anterolaterally over peroneus tertius (flag A3) to innervate the dorsum of the foot (flag A4). Flag 3 marks the lateral malleolus. With permission to use by “Asp AR, Marsland D, Elliot RR. The superficial peroneal nerve: A review of its anatomy and surgical relevance. OA Anatomy 2014 Mar 15;2(1):6. [15].

Figure 2

58 year old woman with a superficial peroneal nerve compression due to peroneus brevis muscle herniation. Findings: axial (A) and coronal (B) T1-weighted sequences show a focal peroneus brevis muscle herniation (red arrows) through a fascial layer defect (white arrow) associated to a little adipose lobule determining compression and neuropathy of the superficial peroneal nerve (black arrows). In B cutaneous marker localized cranially to palpable mass. Technique: Siemens 1.5T Magnetic Resonance System. Turbo Spin Echo axial T1-weighted sequence A (slice thickness 3mm - TR: 500 - TE: 20) and coronal T1-weighted sequence B (slice thickness 3mm - TR: 500 - TE: 18).

Figure 3

58 year old woman with a superficial peroneal nerve compression due to peroneus brevis muscle herniation. Findings: axial (A), coronal (B) and sagittal (C)T2-weighted sequences show a focal peroneus brevis muscle herniation (red arrows) through a fascial layer defect (white arrow) associated to a little adipose lobule determining compression and neuropathy of the superficial peroneal nerve (black arrows). In B cutaneous marker localized cranially to palpable mass. Technique: Siemens 1.5T Magnetic Resonance System. Turbo Spin Echo axial T2-weighted sequence A (slice thickness 3mm - TR: 4600 - TE: 96), coronal T2-weighted sequence B (slice thickness 3mm - TR: 4600 - TE: 98) and sagittal T2-weighted sequence C (slice thickness 3mm - TR: 4190 - TE: 102).

Figure 4

58 year old woman with a superficial peroneal nerve compression due to peroneus brevis muscle herniation. Findings: axial (A) and coronal (B) PD-weighted sequences with fat saturation show a focal peroneus brevis muscle herniation (red arrow) through a fascial layer defect associated to a little adipose lobule determining compression and neuropathy of the superficial peroneal nerve. Neuropathy is shown by mild hyperintensity of the nerve near herniation (black arrows). In B cutaneous marker localized cranially to palpable mass. Technique: Siemens 1.5T Magnetic Resonance System. Turbo Spin Echo axial PD-weighted sequence with fat saturation A (slice thickness 3mm - TR: 3540 - TE: 10) and coronal PD-weighted sequence with fat saturation B (slice thickness 3mm - TR: 3130 - TE: 51).

Figure 5

58 year old woman with a superficial peroneal nerve compression due to peroneus brevis muscle herniation. Findings: axial T1-weighted sequence with fat saturation after contrast administration shows a focal peroneus brevis muscle herniation (red arrow) through a fascial layer defect associated to a little adipose lobule determining compression and mild neuropathic hyperemia of the superficial peroneal nerve (black arrow). Technique: Siemens 1.5T Magnetic Resonance System. Turbo Spin Echo T1-weighted sequence with fat saturation (slice thickness 3mm - TR: 606 - TE: 21). Gadolinium 12 ml iv bolus.