Bratelj Denis, Jaszczuk Phillip, Capone Crescenzo, Dragalina Cristian, Pötzel Tobias, Fiechter Michael
Spine and Orthopedic Surgery, Swiss Paraplegic Center, Nottwil, Switzerland.
Heliyon. 2024 Feb 6;10(3):e25670. doi: 10.1016/j.heliyon.2024.e25670. eCollection 2024 Feb 15.
Interbody cages are routinely used in lumbar reconstruction surgery of deformity cases for restoration of lordosis and sagittal balance of the spine. However, if hyperlordotic implants are inserted into the intervertebral space, special consideration has to be taken concerning the height of the neural foramen during cage implantation. The greater the lordotic angle of the cage is, the higher the posterior size of the cage needs to be in order to avoid neuroforaminal nerve root impingement. In this technical communication, we propose and clinically validate a stepwise mathematic model to predict neuroforaminal height in patients undergoing lumbar reconstruction with hyperlordotic cages. The length of the superior and inferior vertebral end plates including the height of the neural foramen are measured before implantation of the cage in standing sagittal view x-rays. By assumption of an isosceles triangle in combination with the posterior height and the lordotic angle of the cage, the neuroforaminal height after cage implantation can be estimated. By comparison of the predicted neuroforaminal height with age and sex dependent reference values, nerve root impingement can be avoided by selection of the necessary posterior height of the hyperlordotic cage while still gaining sufficient lumbar lordosis.
椎间融合器常用于畸形病例的腰椎重建手术，以恢复脊柱前凸和矢状面平衡。然而，如果将过度前凸的植入物置入椎间隙，在植入融合器时必须特别考虑神经孔的高度。融合器的前凸角度越大，融合器后部尺寸就需要越大，以避免神经孔神经根受压。在本技术交流中，我们提出并临床验证了一种逐步数学模型，以预测接受过度前凸融合器腰椎重建患者的神经孔高度。在站立矢状位X线片上植入融合器之前，测量包括神经孔高度在内的上下椎体终板的长度。通过假设等腰三角形并结合融合器的后部高度和前凸角度，可以估计融合器植入后的神经孔高度。通过将预测的神经孔高度与年龄和性别相关的参考值进行比较，在获得足够腰椎前凸的同时，通过选择过度前凸融合器所需的后部高度，可以避免神经根受压。
