SLR - August 2019 - Daniel P. Bullard

Peroneal Nerve Location at the Fibular Head: An Anatomic Study Using 3D Imaging

Reference: Rausch V, Hackl M, Oppermann J, Leschinger T, Scaal M, Müller LP, Wegmann K. Peroneal Nerve Location at the Fibular Head: An Anatomic Study Using 3d Imaging Arch Orthop Trauma Surg. 2019 Jul;139(7):921-926. doi: 10.1007/s00402-019-03141-7. Epub 2019 Feb 8.

Scientific Literature Review

Reviewed By: Daniel P. Bullard, DPM
Residency Program: St. Vincent Charity Medical Center – Cleveland, OH

Podiatric Relevance: Accurately identifying the location of the common peroneal nerve plays an important role in acute ankle trauma with regard to performing closed reduction in emergency settings. The ability to identify the location and properly anesthetize the common peroneal nerve serves as pain relief to the anterior and lateral aspects of the ankle. Also, this will prevent peroneal spasm, which may serve to obtain and maintain reduction.   

Methods: Cadaveric dissection of 18 specimens (9 males, 9 females) was performed at the level of the fibular head. Once the nerve was identified, its course was traced using radiopaque wires in all specimens to ensure proper visualization of its location via computed tomographic imaging. Three dimensional scans were then taken of the knee and proximal lower leg using an Arcadis Orbic 3D imaging intensifier. Two axes were identified, a z-axis at the level of the tibial plateau and a y-axis at the widest mediolateral distance of the tibial plateau. Impax-software was used to measure 4 sites: (1) the width of the tibial plateau, (2) posterior and lateral distance of the nerve relative to the tibia, (3) the posterior and lateral distances from the fibula, and (4) the site of branching of the common peroneal nerve relative the proximal fibular tip.

Results: The mean distance of the common peroneal nerve relative to the tibia was 7.92mm posterior to the tibial plateau’s posterior surface and 1.31 mm lateral to the lateral surface of the tibial plateau on axial images. With respect to the tip of the fibula, the common peroneal nerve was located at a mean distance of 8.23 mm posterior and -2.77 mm mediolateral on axial images. The nerve branched on average 27.56 mm from the tip of the fibula (p-value<0.0001). The deep peroneal nerve crossed the middle of the fibular shaft at 38.04 mm distal to the tip of the fibula on average, while the superficial peroneal crossed at 48.74 mm on average.

Conclusions:
On axial imaging, the common peroneal nerve sat, an average of 8.23 mm posterior to the fibula at the level of the tibial plateau, where it split into its two terminal branches 27.56 mm distal to the tip of the fibula, on average. Using this knowledge, we can systematically identify the approximate location of the nerve by identifying the tip of the tibial plateau and drawing a straight line laterally parallel to the course of the plateau. When the fibula is traversed, we can comfortably place our injection 8mm posterior to the fibula. Care should be taken to avoid incomplete anesthesia of both branches of the common peroneal nerve by staying within 28 mm of the tip of the fibula.   

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