Fig. 3.

Reconstruction of the lumbar spine using a combined anterior (anterior lumbar interbody fusion, ALIF) and posterior (pedicle screws) surgical access route. Pre- (A) and post-surgical (B) height of the neural foramen after a combined anterior and posterior approach using a hyperlordotic cage (16° lordotic angle). The length of the bony vertebral endplates (red lines) including the height of the bony part of the neural foramen (yellow lines) can be measured in sagittal view 2D X-rays and together with the selected cage parameters (lordotic angle and posterior height of the cage) the post-surgical height of the neural foramen can be estimated. Therefore, the correct size of the cage can be chosen while sufficient reconstruction of lumbar lordosis can still be achieved.