Proportional localisation of the peroneal nerve along the fibula

The common peroneal nerve (CPN) and the superficial peroneal nerve (SPN) are among the most commonly iatrogenically injured peripheral nerves. The aim of this study was to localize the division point of the CPN into the deep peroneal nerve (DPN) and SPN and the exit point of the SPN through the crural fascia in relation to the length of the fibula.

101 lower extremities were included in this given study. The distance between the apex of the fibular head and the distal tip of the lateral malleolus was defined as the fibular length (FL). Measurements were taken from the apex of the fibular head to the division site of the CPN and from the tip of the lateral malleolus and the perforation point of the SPN. Data were projected proportionally along the FL and analysed using Dirichlet regression models. The rationale behind this approach was to predict the location of these anatomical characteristics in a reliable manner. Due to variations of anatomical structures depending on body length (e.g., taller people tend to have longer fibulae), it is reasonable to assume that the CPN's/SPN's location may also vary proportionally and is not fixed in relation to the lateral malleolus.

The mean FL was 37.2 cm (SD: 2.8; median: 36.9; range: 32.4-45.6; IQR: 3.6). The CPN's division point was located at a mean of 3.3 cm (SD: 1.2; median: 3.2; range: 1.6 cm proximal to 8.2 cm distal to the tip; IQR: 1.3) distal to the apex of the fibular head, which corresponded to an interval between 3.9 % and 15.9 % of the FL, starting from the same landmark. The exit point of the SPN was at an average length of 17.1 cm (SD: 4.5; median: 17.1; range: 7-23.7; IQR: 7.9) proximal to the tip of the lateral malleolus, matching a proportional interval between 23.9 % and 69.0 % of the FL. Concerning the division point of the CPN, there was less precision (i.e., more variance) in females (p = .042) and right-sided specimens (p = .007), compared to male left-sided specimens. Regarding the SPN's perforation point, compared to fixation with ethanol and left-sided specimens, the diversion point was higher in Thiel-specimens (p = .034) and the interaction (Thiel on the right side; p = .029).

The current results offer easily applicable data for intraoperative localisation of the peroneal nerve's main portions at risk.