ORIGINAL ARTICLE Surgeon’s perception of margins in spinal en bloc resection surgeries: how reliable is it? Ran Lador 1 • Alessandro Gasbarrini 2 • Marco Gambarotti 3 • Stefano Bandiera 2 • Riccardo Ghermandi 2 • Stefano Boriani 2 Received: 6 August 2016 / Revised: 1 December 2016 / Accepted: 18 January 2017 Ó Springer-Verlag Berlin Heidelberg 2017 Abstract Purpose and Background En bloc resections aim at sur- gically removing a tumor in a single, intact piece, fully encased by a continuous shell of healthy tissue—the ‘‘margin’’. Intraoperative continuous assessment of the plane of resection regarding the tumor’s margins is para- mount. The goal of this study was to evaluate the accuracy of experienced spinal tumor surgeons’ perception of these margins. Methods A retrospective analysis of a prospectively col- lected data of 1681 patients affected by spine tumors of whom 217 en bloc resections was performed. Surgeons’ intraoperative assessment was compared to the histopathological assessment. Results Most were primary—163 (42 benign and 121 malignant), metastases occurred in 54 cases. ‘Wide’ mar- gins were obtained in 126 cases; ‘marginal’ in 60 cases, and ‘intralesional’ in 31 cases. Surgeons assessed clear margins in 109 cases and contaminated in 108 cases. When considering marginal margins as a contaminated resection, the surgeon’s assessment of clear resection had a sensi- tivity of 76.89%, specificity of 86.81%, PPV and NPV (positive and negative predictive values) were 88.99 and 73.15%, respectively. Inter-observer agreement was 0.62. When considering marginal margins as a clear resection, the surgeon’s assessment of clear resection had a sensi- tivity of 64.5%, specificity of 100%, PPV and NPV were 100 and 0%, respectively. Inter-observer agreement was 0.29. Conclusion Surgeons are fairly accurate in their intraop- erative assessment of clear margins achieved; however, this accuracy is not perfect and exploring ways to improve this intraoperative assessment is of major importance possibly impacting the outcome of the treatment. Keywords Margins Á Spine tumors Á En bloc resection Á Intraoperative assessment Á Recurrence Introduction En bloc resections [1] are the procedures aiming at surgi- cally removing a tumor in a single, intact piece, fully encased by a continuous shell of healthy tissue, which is defined as the ‘‘margin’’. As described by Enneking [2] for bone tumors, there are four types of surgical margins, each directly relates to the oncological prognosis of the patient. The different types were termed intralesional, marginal wide and radical with regard to the tumor’s pseudocapsule and the chance of remaining tumor cells after excision. Intralesional/Intracapsular margins means that the lesion has been removed from within the tumor’s pseudocapsule, or that the tumor pseudocapsule has been violated during the en bloc resection procedure: in this case, the pathologist can demonstrate vital tumor on the surface of the specimen. As a consequence, we can expect that gross tumor is left in the wound. Marginal margins mean that the lesion has been removed en bloc, and the plain of dissection has been extracapsular either between the pseudocapsule and the & Ran Lador ranilador@gmail.com 1 Unit of Spine Surgery, Tel-Aviv Medical Center, 6 Weizman St., Tel-Aviv 64239, Israel 2 Unit of Oncologic Spine Surgery, Department of Oncologic and Degenerative Spine Surgery, Rizzoli Institute, Bologna, Italy 3 Unit of Pathology, Rizzoli Institute, Bologna, Italy 123 Eur Spine J DOI 10.1007/s00586-017-4967-0