Funding
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. However, we are pleased to acknowledge that Justimplant, a leading distributor of spine surgery implants, generously assumed the costs of open access publication for this research. The study procedures were paid for by the Catalan Institute of Health and did not incur any additional costs. The investigators received no economic compensation for carrying out the study.