{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T19:55:06Z","timestamp":1791230106155,"version":"4.1.0"},"reference-count":23,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,5,30]],"date-time":"2025-05-30T00:00:00Z","timestamp":1748563200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Biportal endoscopic spine surgery (BESS) is one of the minimally invasive spine surgery techniques. BESS has several advantages, such as better visualization, less muscle injury, early rehabilitation, etc. Due to its clear visualization, delicate intraoperative hemostasis of the bleeding foci, including cancellous bone and small epidural vessels, can be achieved. Therefore, some authors have reported that BESS resulted in less intraoperative visible blood loss (VBL) compared to conventional open surgery. However, it is difficult to analyze the exact amount of intraoperative blood loss because of the continuous normal saline irrigation. In addition, hidden blood loss (HBL) tends to be overlooked, and the amount of HBL might be larger than expected. We aim to calculate the amount of HBL during BESS and to compare our findings with convention open surgery. Methods: We retrospectively obtained the clinical data of patients that underwent lumbar central decompression from July 2021 to June 2024. Patients were divided into two groups: the BESS group that underwent biportal endoscopic lumbar decompression, and the open surgery group that underwent open decompression. Both groups used unilateral laminotomy and bilateral decompression techniques. Total blood loss (TBL) using preoperative and postoperative change in hematocrit (Hct) was measured using Gross\u2019s formula and the Nadler equation. Since TBL consists of VBL and HBL, HBL was calculated by subtracting the VBL measured intraoperatively from TBL. Results: A total of sixty-six patients in the BESS group and seventeen patients in the open surgery group were included in the study. The TBL was 247.16 \u00b1 346.88 mL in the BESS group and 298.71 \u00b1 256.65 mL in the open surgery group, without significant difference (p = 0.569). The calculated HBL values were 149.44 \u00b1 344.08 mL in the BESS group and 171.42 \u00b1 243.93 mL in the open surgery group. The HBL in the BESS group was lower than the HBL in the open surgery group, without significant difference (p = 0.764). Conclusions: The TBL and HBL during lumbar central decompression were smaller in patients who underwent BESS compared to those who underwent open surgery. While TBL was significantly lower in BESS, HBL did not show statistical significance between the two groups. HBL during BESS should not be neglected, and related hemodynamics should be considered postoperatively.<\/jats:p>","DOI":"10.3390\/jcm14113878","type":"journal-article","created":{"date-parts":[[2025,6,2]],"date-time":"2025-06-02T10:21:49Z","timestamp":1748859709000},"page":"3878","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Comparison of Hidden Blood Loss in Biportal Endoscopic Spine Surgery and Open Surgery in the Lumbar Spine: A Retrospective Multicenter Study"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6355-4105","authenticated-orcid":false,"given":"Dae-Geun","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Orthopedic Surgery, Soonchunhyang University Gumi Hospital, Soonchunhyang University College of Medicine, Gumi 39568, Republic of Korea"},{"name":"Department of Orthopedic Surgery, Dream General Hospital, Daegu 702-752, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3974-9460","authenticated-orcid":false,"given":"Eugene J.","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Kyungpook National University Hospital, Kyungpook National University College of Medicine, Daegu 41944, Republic of Korea"},{"name":"Spine Center, Bogang Hospital, Daegu 42801, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Woo-Kie","family":"Min","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Kyungpook National University Hospital, Kyungpook National University College of Medicine, Daegu 41944, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sang-Bum","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Sejong Chungnam National University Hospital, Chungnam National University College of Medicine, Daejeon 30099, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5137-2694","authenticated-orcid":false,"given":"Gaeun","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Biostatistics, Soonchunhyang University Gumi Hospital, Gumi 39568, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3372-8260","authenticated-orcid":false,"given":"Sung","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Daegu Fatima Hospital, Daegu 41199, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"111S","DOI":"10.1177\/2192568219887364","article-title":"AOSpine Consensus Paper on Nomenclature for Working-Channel Endoscopic Spinal Procedures","volume":"10","author":"Hofstetter","year":"2020","journal-title":"Global Spine J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"418","DOI":"10.31616\/asj.2021.0527","article-title":"Comparison of Unilateral Biportal Endoscopy Decompression and Microscopic Decompression Effectiveness in Lumbar Spinal Stenosis Treatment: A Systematic Review and Meta-analysis","volume":"17","author":"Junjie","year":"2023","journal-title":"Asian Spine J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1016\/j.jos.2019.05.022","article-title":"Clinical and radiological outcomes between biportal endoscopic decompression and microscopic decompression in lumbar spinal stenosis","volume":"25","author":"Min","year":"2020","journal-title":"J. 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