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However, its performance in the surgical environment, with its unique challenges, remains largely unexplored. This work benchmarks state-of-the-art inside-out methods, namely, visual Simultaneous Localization and Mapping (vSLAM) methods. To this end, we collected a first-of-its-kind dataset in spine endoscopy, providing ground-truth tool poses.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We recorded endoscopic spine surgeries performed on a high-fidelity training model in a real operating room environment, containing synchronized stereo images from tool-mounted cameras, sub-millimetric ground truth pose data from a commercial optical tracking system, and the endoscopic feed. Using this dataset, the instrument tracking accuracy of a selected number of vSLAM algorithms was compared.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The best performing approach achieved a root mean squared absolute trajectory error of 2.0\u00a0mm and 1.47\u00a0degrees, reaching accuracies of around 1\u00a0mm and 1\u00a0degree on selected sequences. However, it shows degraded performance in the presence of challenges such as occlusions and scene-object dynamics.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Markerless inside-out tracking using vSLAM demonstrated high accuracy, indicating potential feasibility for navigated endoscopic spine applications. Our evaluation revealed that current algorithms remain insufficiently robust for routine clinical use. The presented study and dataset establish a foundation for future research toward reliable, real-time inside-out navigation in minimally invasive surgery.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s11548-026-03625-z","type":"journal-article","created":{"date-parts":[[2026,4,27]],"date-time":"2026-04-27T16:53:10Z","timestamp":1777308790000},"page":"1053-1060","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Markerless inside-out tool tracking for endoscopic spine surgery: a benchmarking study and clinical dataset"],"prefix":"10.1007","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-3445-3932","authenticated-orcid":false,"given":"Peter","family":"Zhang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Youyang","family":"Shen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fr\u00e9d\u00e9ric","family":"Giraud","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicola A.","family":"Cavalcanti","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marc","family":"Pollefeys","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christoph J.","family":"Laux","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philipp","family":"F\u00fcrnstahl","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hooman","family":"Esfandiari","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,4,27]]},"reference":[{"issue":"1","key":"3625_CR1","doi-asserted-by":"publisher","first-page":"6","DOI":"10.14245\/ns.1836322.161","volume":"16","author":"M Kim","year":"2019","unstructured":"Kim M, Kim H-S, Oh SW, Adsul NM, Singh R, Kashlan ON, Noh JH, Jang IT, Oh SH (2019) Evolution of Spinal Endoscopic Surgery. 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