Positional alterations of the Kambin's triangle and foraminal areas in the lumbosacral region.

Objective: The aim of this anatomical study was to compare the effects of the prone and lateral decubitus positions in endoscopic disc surgery on the Kambin's triangle (KT) and neural foramina zones in the lumbosacral region.

Methods: The study included 32 healthy volunteers (16 females and 16 males). Bilateral KT areas (KTA) and neural foraminal areas (FA) of the L4-L5 and L5-S1 levels in the prone and lateral decubitus positions were calculated depending on the freehand region of interest measurements on magnetic resonance images. KTA and FA values for each side and level in the prone and lateral decubitus positions were compared.

Results: Mean left KTA value in the prone and right lateral decubitus positions was 0.58 cm(2) and 0.69 cm(2), respectively, for L4-L5; and 0.69 cm(2) and 0.78 cm(2), respectively, for L5-S1 levels. Mean right KTA values in the prone and left lateral decubitus positions were 0.54 cm(2) and 0.65 cm(2) for L4-L5; and 0.69 cm(2) and 0.81 cm(2) for L5-S1, respectively. The differences in the KTA between prone and lateral decubitus positions for both levels and both sides were statistically significant (p=0.05). Only the difference in the FA between the prone and lateral decubitus positions at L5-S1 level on the right side was statistically significant (p=0.05).

Conclusion: The KTA is wider in the lateral decubitus position than in the prone position at the levels of L4-L5 and L5-S1.