Comparison of Anesthetic Effects of Spinal Anesthesia at L5-S1 and L3-4 under Real-time Ultrasound Guidance in Knee Arthroplasty

Comparison of Anesthetic Effects of Spinal Anesthesia at L5-S1 and L3-4 under Real-time Ultrasound Guidance in Knee Arthroplasty | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Comparison of Anesthetic Effects of Spinal Anesthesia at L5-S1 and L3-4 under Real-time Ultrasound Guidance in Knee Arthroplasty Yuekun Liu, Haiyan Li, Jinqin Bi, Chengrun Lu, Wenchao Li, Xiangguo Chai, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7404074/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Dec, 2025 Read the published version in BMC Anesthesiology → Version 1 posted 10 You are reading this latest preprint version Abstract Background: Spinal anesthesia at L5-S1 is rarely selected in clinical anesthesia, and many characteristics of L5-S1 spinal anesthesia are not well-documented in the literature. Objective： To investigate the efficacy and safety of real-time ultrasound-guided L5-S1 and L3-4 space spinal anesthesia in knee arthroplasty. Methods: A total of 46 patients who underwent elective knee arthroplasty from December 2023 to December 2024 were randomly divided into L5-S1 (group A) and L3-4 (group B) with 23 cases each. All patients were treated with paraveterbral approach spinal anesthesia under real-time ultrasound guidance, a sagittal puncture was performed in the lateral decubitus position of the affected extremity. Cerebrospinal fluid was observed in the lumbar puncture syringe to determine the success of the puncture. After successful puncture, 15mg of 0.75% bupivacaine (0.75% bupivacaine 2ml + cerebrospinal fluid 1ml) was injected. A third party recorded the highest sensory block level, the time required to reach the highest sensory block level, the incisional sensory block recovery time, the mean arterial pressure and heart rate and their changes at each time point during the operation, the operation time, the satisfaction rate of anesthesia, the use of vasopressors, and the incidence of post-operative complications (headache, parasthesias, hypotension, thrombotic events, nausea and vomiting, etc.). Results: In the L5-S1 group, the highest blocked spinal segment was lower and the total number of spinal segments blocked were fewer, the time to reach highest blocked spinal segment was longer, the recovery time of incisional sensory block was later (P < 0.001). The mean arterial pressure of patients in the L5-S1 group decreased at various time points such as 10 minutes after spinal anesthesia, at the beginning of the surgery, and before PACU discharge. However, the decrease in blood pressure was smaller (P < 0.05), with greater hemodynamic stability. Eight patients in the L3-4 group required vasopressors to maintain hemodynamic stability. The satisfaction rate of anesthesia in both groups was 100%. Conclusion: Under real-time ultrasound guidance, both L5-S1 and L3-4 intervertebral space spinal anesthesia can be safely used in knee joint replacement surgeries. Under the same dose of bupivacaine, the total number of spinal segments blocked in the L5-S1 were fewer, the recovery time of incision sensory block was longer, and the intraoperative hemodynamics were more stable. Trial registration: This trial was registered on July 21, 2025 at the Chinese Clinical Trial center (No. ChiCTR2500106275). Retrospectively registered. Real-time ultrasound guidance Spinal anesthesia total knee arthroplasty Bupivacaine Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 01 Dec, 2025 Read the published version in BMC Anesthesiology → Version 1 posted Editorial decision: Revision requested 06 Oct, 2025 Reviews received at journal 30 Sep, 2025 Reviewers agreed at journal 21 Sep, 2025 Reviews received at journal 17 Sep, 2025 Reviewers agreed at journal 16 Sep, 2025 Reviewers invited by journal 11 Sep, 2025 Editor assigned by journal 05 Sep, 2025 Editor invited by journal 04 Sep, 2025 Submission checks completed at journal 02 Sep, 2025 First submitted to journal 02 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7404074","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":516364754,"identity":"f8100b96-289a-471c-b72c-3d9f75e0e765","order_by":0,"name":"Yuekun Liu","email":"","orcid":"","institution":"The First People's Hospital of Anning, Kunming University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Yuekun","middleName":"","lastName":"Liu","suffix":""},{"id":516364755,"identity":"82e7b902-8e1c-426a-9fee-5cc510600b81","order_by":1,"name":"Haiyan Li","email":"","orcid":"","institution":"The First 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Arthroplasty","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-anesthesiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bane","sideBox":"Learn more about [BMC Anesthesiology](http://bmcanesthesiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bane","title":"BMC Anesthesiology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Real-time ultrasound guidance, Spinal anesthesia, total knee arthroplasty, Bupivacaine","lastPublishedDoi":"10.21203/rs.3.rs-7404074/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7404074/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground: Spinal anesthesia at L5-S1 is rarely selected in clinical anesthesia, and many characteristics of L5-S1 spinal anesthesia are not well-documented in the literature.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eObjective： To investigate the efficacy and safety of real-time ultrasound-guided L5-S1 and L3-4 space spinal anesthesia in knee arthroplasty.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMethods: A total of 46 patients who underwent elective knee arthroplasty from December 2023 to December 2024 were randomly divided into L5-S1 (group A) and L3-4 (group B) with 23 cases each. All patients were treated with paraveterbral approach spinal anesthesia under real-time ultrasound guidance, a sagittal puncture was performed in the lateral decubitus position of the affected extremity. Cerebrospinal fluid was observed in the lumbar puncture syringe to determine the success of the puncture. After successful puncture, 15mg of 0.75% bupivacaine (0.75% bupivacaine 2ml + cerebrospinal fluid 1ml) was injected. A third party recorded the highest sensory block level, the time required to reach the highest sensory block level, the incisional sensory block recovery time, the mean arterial pressure and heart rate and their changes at each time point during the operation, the operation time, the satisfaction rate of anesthesia, the use of vasopressors, and the incidence of post-operative complications (headache, parasthesias, hypotension, thrombotic events, nausea and vomiting, etc.).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eResults: In the L5-S1 group, the highest blocked spinal segment was lower and the total number of spinal segments blocked were fewer, the time to reach highest blocked spinal segment was longer, the recovery time of incisional sensory block was later (P \u0026lt; 0.001). The mean arterial pressure of patients in the L5-S1 group decreased at various time points such as 10 minutes after spinal anesthesia, at the beginning of the surgery, and before PACU discharge. However, the decrease in blood pressure was smaller (P \u0026lt; 0.05), with greater hemodynamic stability. Eight patients in the L3-4 group required vasopressors to maintain hemodynamic stability. The satisfaction rate of anesthesia in both groups was 100%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConclusion: Under real-time ultrasound guidance, both L5-S1 and L3-4 intervertebral space spinal anesthesia can be safely used in knee joint replacement surgeries. Under the same dose of bupivacaine, the total number of spinal segments blocked in the L5-S1 were fewer, the recovery time of incision sensory block was longer, and the intraoperative hemodynamics were more stable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTrial registration: This trial was registered on July 21, 2025 at the Chinese Clinical Trial center (No. ChiCTR2500106275). 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