The Importance of Balance in the Use of Spine Prostheses

• lumbar spine
• artificial disc

We started implanting lumbar disc prostheses via a minimally invasive anterior approach in 1999 with great enthusiasm but also with a lot of uncertainty.1 Twenty-five years later, the uncertainty has been lifted thanks to regular monitoring, which has shown the excellent results of these pioneering prostheses (Prodisc L [1999]2 and Maverick [2002]1).

We have gradually improved the indications by favoring the L4-L5 and L5-S1 levels and by making a hybrid construct first presented at the London Spine Arthoplasty Society meeting in 2003 and published in 2005.3 The recommendations were the restoration of lordosis by anterior lumbar interbody fusion for L5-S1 and prosthesis in L4-L5. This hybrid construct gives excellent results on long-term follow-up.

We studied a lot, particularly the importance of rebalancing the spine linked to the use of prostheses.4 Since 2005,1 we have shown its importance on sagittal balance, with the adaptability of the prosthesis allowing a better economic balance. To continue to improve the indications and justify the use of disc prostheses, particularly in the lumbar region5 but also in the cervical region, we have extended the static analysis of the spine to dynamic analysis.6 For 2 years, all patients have been analyzed using a revolutionary system for collecting anteroposterior and lateral spinal alignment using sensors stuck to the skin on predefined cutaneous anatomic spinous processes and associated with a digital twin of the patient based on radiological imaging. Pre- and postoperative EOS imaging is used to create a digital twin, an avatar of the frontal and sagittal alignment, including the lower limbs.7 This dynamic analysis allows us to better understand the importance of the hip extension reserve, pelvic retroversion, compensatory mechanisms, thoracic kyphosis, and cervical spine position. This can be done while walking but also in a sitting position, which has become a preferred position for many workers. This new analysis allows us to better understand the success of prostheses and also to glimpse new indications. The success story continues.

• This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2025 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.