Inferior long-term outcomes after surgery for lumbar disc herniation in patients with prior lumbar spine surgery.

"Declarations Ethical approvalAll procedures performed in studies involving human participants were in accordance with the ethical standards of the ethics committee of Helsinki University Hospital and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consentInformed consent was obtained from all individual participants included in the study. Conflict of interestAll authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript. Conflict of interest All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript."

"Funding Open Access funding provided by University of Helsinki (including Helsinki University Central Hospital). M.R. received personal research grants from the Maire Taponen Foundation and The Finnish Medical Foundation."