Real-time ultrasound-guided vs. landmark-guided spinal anesthesia for scheduled cesarean delivery and door-to-skin incision time: a retrospective study (2019-2024)

Real-time ultrasound-guided vs. landmark-guided spinal anesthesia for scheduled cesarean delivery and door-to-skin incision time: a retrospective study (2019-2024) | 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 Real-time ultrasound-guided vs. landmark-guided spinal anesthesia for scheduled cesarean delivery and door-to-skin incision time: a retrospective study (2019-2024) Tianzhu Liu, Xingxing Sun, Yong Liu, Wei Mei This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8687110/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Real-time ultrasound can facilitate spinal anesthesia. However, it remains uncertain whether this technique prolongs the time for parturients entry into the operating room to skin incision compared with the landmark-guided method. We conducted a retrospective, propensity-score-matched study involving patients who received real-time and landmark-guided spinal anesthesia over a five-year period (2019-2024). Results showed a significantly time reduction from “door” to “skin incision” in the landmark-guided spinal anesthesia group compared to the real-time group (37.9 ± 13.7 minutes vs. 41.9 ± 18.3 minutes, P < 0.05). Both the age, body mass index and American Society of Anesthesiologists classification remained no significant correlation with the time reduction from “door” to “skin incision”. Figures Figure 1 Introduction Spinal anesthesia has been widely adopted in cesarean section procedures due to its ability to avoid systematic medication while ensuring the safety of both the mother and the fetus 1 . However, anatomical landmark-based neuraxial block is insufficient for patients with abnormal spinal structure or the elderly 2 , 3 . Pre-procedure ultrasonic assistance improves spinal anesthesia performance, with a first-pass success rate of 85.7% and reduced number of attempts, while real-time ultrasound-guided spinal anesthesia (RT-SA) achieves a success rate of up to 95.2% 4,5 . However, despite these advantages, the extent to which RT-SA technology can accelerate the turnover of cesarean sections and improve operating room efficiency remains a critical consideration for its practical implementation. Chen LY et al have shown that ultrasound-assisted localization before needle puncture has more time-saving effect than RT-SA in elderly patients 6 , highlighting the need to investigate the RT-SA’s impact on delaying non-operative time in obstetric surgeries 7 , 8 . Among RT-SA approaches, the parasagittal approach is widely used for passing fewer ligaments and enhancing intraspinal structure visibility 9 . It benefits complex cases such as obese and abnormal anatomy by reducing procedural complexity and improving success rate and safety 10 , but its technical difficulty necessitates time-efficiency research for clinical practice 11 , 12 . Herein, we conducted a single-center retrospective cohort study to verify the impact of this technique and associated demographic characteristics on DTS (the time from patients’ entry to skin incision). Methods This was a single-center retrospective study. We were authorized by Tongji Hospital Ethics Review Committee (TJ-IRB202410047) on October 15, 2024, and registered on ClinicalTrials.gov (NCT06656793) on October 23, 2024. We conducted a retrospective review of the electronic medical records (EMR) of patients who received RT-SA performed by experienced anesthesiologists between January 1, 2019 and May 29, 2024. The initial population was determined from the EMR software (DoCare v5.0). Only parturients with scheduled cesarean section were included in this study. Finally, we evaluated the effect of RT-SA on cesarean delivery DTS in 928 patients (371 in RT-SA group, 557 in LM-SA group). Statistical analyses were performed in R (4.5.1) using MatchIt, dplyr, and readxl packages. Key variables included the primary outcome DTS, and covariates (age, BMI, ASA classification [Ⅰ-Ⅲ; with level Ⅱ as the reference]). Propensity scores (PS) were estimated via logistic regression incorporating the interaction term of age and BMI. 1:1 nearest neighbor propensity score matching (PSM) was conducted without replacement, with a caliper of 0.2 standard deviations (SD) of the logit-transformed PS. After PSM, the matched dataset was extracted. Covariate balance before and after matching was assessed using standardized mean differences (SMD) with a threshold of SMD < 0.1 considered as adequate balance, via the bal.tab function from the cobalt package. For inferential statistics on the matched data (paired design due to 1:1 matching). Continuous variables (age, BMI, DTS) were compared using paired t-tests. The ordered categorical variable (ASA classification) was compared using the paired Wilcoxon signed-rank test. Descriptive statistics were presented as mean ± SD for continuous variables and numbers (percentages) for categorical variables. For continuous variables including age, BMI, and dts, descriptive statistics were presented as Mean ± Standard Deviation, with the Shapiro-Wilk test used to assess normality; for inferential statistics, the paired t-test was applied if the data met the normality assumption in a paired design, while the paired Wilcoxon signed-rank test was used when normality was not satisfied, and in an independent design, the independent samples t-test was adopted for normally distributed data and the Mann-Whitney U test for non-normally distributed data. For the categorical variable (ASA classification), descriptive statistics were expressed as frequency and percentage, with the paired Wilcoxon signed-rank test used for inferential statistics in a paired design and the Kruskal-Wallis test for an independent design. For the RT-SA group, patients were placed in the lateral position, with ultrasound-guided puncture; after local anesthesia via an 18G needle, a 25G needle was advanced through the 18G needle to the subarachnoid space, and local anesthetic was injected upon confirmation of cerebrospinal fluid outflow (Fig. 1 A-B). For the LM-SA group, patients were in the flexed lateral decubitus position; puncture was localized via Tuffier’s line, two distinct pops were felt, subarachnoid injection was proceeded by cerebrospinal fluid outflow. Results A total of 928 patients were initially included, with 371 in the RT-SA group and 557 in the LM-SA group. After 1:1 nearest neighbor PSM without replacement (caliper set at 0.2 standard deviations of the logit-transformed propensity score), 271 pairs were successfully matched, resulting in 271 patients in each group (Table 1 ). Post-matching, all covariates achieved adequate balance (SMD < 0.1, Fig. 1 C). Unmatched RT-SA and LM-SA patients showed significant differences in mean age and BMI (both P < 0.0001), but these differences disappeared after matching (P = 0.7774 for age, P = 0.3757 for BMI), while ASA classification had no significant differences either before (P = 0.9966) or after matching (P = 0.2698). For the primary outcome DTS, unmatched RT-SA had a mean of 40.8 ± 17.3 minutes versus 37.0 ± 11.4 minutes in LM-SA (P = 0.0032), while post-matching, RT-SA had 41.9 ± 18.3 minutes and LM-SA had 37.9 ± 13.7 minutes (P = 0.0114). Table 1 Demographic and propensity score matching data. Unmatched Matched Demographic data RT-SA (n = 371) LM-SA (n = 557) P value RT-SA (n = 271) LM-SA (n = 271) P value Age (yr) 35.6 ± 7.6 39.6 ± 4.7 < 0.0001 43.0 ± 17.8 43.0 ± 11.6 0.7774 BMI (kg / m 2 ) 24.9 ± 5.0 26.8 ± 3.9 < 0.0001 23.9 ± 3.7 26.5 ± 4.1 0.3757 ASA, n (%) I Ⅱ Ⅲ 145 (39.1) 209 (56.3) 17 (4.6) 216 (36.9) 318 (57.1) 23 (4.1) 0.9966 108 (39.9) 151 (55.7) 12(4.4) 101 (37.3) 156 (57.6) 14 (5.2) 0.2698 Overall DTS (min) 40.8 ± 17.3 37.0 ± 11.4 0.0032 41.9 ± 18.3 37.9 ± 13.7 0.0114 The data are presented as mean ± SD for continuous variables and numbers (percentages) for categorical variables. RT-SA, real-time ultrasound-guided spinal anesthesia; LM-SA, landmark-guided spinal anesthesia; BMI, body mass index; ASA, American Society of Anesthesiologists; DTS, time consumption from patients’ entry to skin incision; SD, standard deviation. Discussion Ultrasound-guided pencil-point spinal anesthesia has been widely adopted by anesthesiologists due to its visuality and low cost 12 . However, anesthesiologists often have mixed attitudes towards it 13,14 . For elderly patients, ultrasound visualization guidance for spinal anesthesia is extremely important as it can avoid multiple attempts. For obese patients, ultrasound-guided spinal anesthesia can significantly improve the first-pass success rate 10 . However, some scholars believe that the learning curve associated with the RT-SA technique is often a significant barrier, resulting in longer procedure completion times compared to LM-SA technique 9 . Our research has confirmed that when PSM effectively balance baseline covariates (age, BMI, ASA), ensuring the DTS difference is attributable to the technique itself. The RT-SA technique is indeed more time-consuming than the LM-SA technique. The potential reasons may include the need for the operator to perform aseptic preparation of the probe, the additional time required to accurately identify the needle tip and target location on the ultrasound image, and the necessity of real-time trajectory tracking. On the other hand, our research has found that there is only an average difference of 4 minutes in DTS between RT-SA and LM-SA. This difference is almost negligible in the nearly 40-minute anesthesia preparation time, especially for patients with unexpected or anticipated difficulties in spinal puncture 15 . The longer 4-minute duration is not a hindrance for experienced RT-SA technique users. However, at the current stage, LM-SA seems to be a better choice for time-sensitive patients. Future prospective RCTs are needed to validate findings. Conclusion We need to make some efforts in the training strategy of the RT-SA technology, especially in terms of process optimization, innovative technical training methods, and new training equipment such as artificial intelligence devices and deep learning-assisted course learning 11 . For elective cesarean section surgeries, although a 4-minute difference may not have clinical significance, it can still indicate that we urgently need to popularize the RT-SA technology for reducing number of attempts and improving first-time success rate, so that it can be mastered and proficiently applied by more anesthesiologists, achieving time efficiency comparable to or even surpassing that of LM-SA, 16 . Abbreviations RT SA real-time ultrasound-guided spinal anesthesia LM SA landmark-guided spinal anesthesia DTS door to-skin incision time Declarations Ethics approval and consent to participate We were authorized by Tongji Hospital Ethics Review Committee (TJ-IRB202410047) on October 15, 2024, and registered on ClinicalTrials.gov (NCT06656793) on October 23, 2024. This study was conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. Informed consent was exempted by the ethics committee due to the use of anonymized, de-identified routine clinical data with no direct participant contact, in line with the 1964 Declaration of Helsinki and its amendments. Strict data privacy and confidentiality protocols were followed in all study stages. Consent for publication Not applicable. Competing Interests The authors declare no competing interests. Funding This work was supported by Chen xiaoping Foundation for the development of science and technology of Hubei province (Nos.CXPJJH125001-2558; Tianzhu Liu) and National Natural Science Foundation of China (Nos.82471289; Wei Mei). Author Contribution Study conception/design: Wei Mei.Data acquisition: Yong Liu, Xingxing Sun.Data analysis/interpretation: Tianzhu Liu.Drafting of the manuscript: Tianzhu Liu, Wei Mei.Critical revision of the manuscript for important intellectual content: all authors.Statistical analysis: Tianzhu Liu.Administrative, technical, or material support: Wei Mei. Acknowledgement We extend our heartfelt gratitude to our partners and the engineers responsible for the EMR system, for their invaluable support. Availability of data and materials Not applicable. References Singleton ANE, Moorthy BN, Buggy A. Regional and neuraxial anaesthesia techniques for spinal surgery: a scoping review. Br J Anaesth Oct. 2022;129(4):598–611. 10.1016/j.bja.2022.05.028 . Qu B, Chen L, Zhang Y, et al. Landmark-guided versus modified ultrasound-assisted Paramedian techniques in combined spinal-epidural anesthesia for elderly patients with hip fractures: a randomized controlled trial. BMC Anesthesiol. 2020;20(1):248. 10.1186/s12871-020-01172-x . 2020/09/28. Park SK, Bae J, Yoo S, et al. Ultrasound-Assisted Versus Landmark-Guided Spinal Anesthesia in Patients With Abnormal Spinal Anatomy: A Randomized Controlled Trial. Anesth Analg Mar. 2020;130(3):787–95. 10.1213/ane.0000000000004600 . Liu Y, Qian W, Ke XJ, Mei W. Real-time Ultrasound-guided Spinal Anesthesia Using a New Paramedian Transverse Approach. Current Med Science Oct. 2018;38(5):910–3. 10.1007/s11596-018-1961-7 . Chin A, Crooke B, Heywood L, Brijball R, Pelecanos AM, Abeypala W. A randomised controlled trial comparing needle movements during combined spinal-epidural anaesthesia with and without ultrasound assistance. Anaesthesia Apr. 2018;73(4):466–73. 10.1111/anae.14206 . Chen LY, Huang JL, Zhang YL, et al. Real-Time Ultrasound-Guided Versus Ultrasound-Assisted Spinal Anesthesia in Elderly Patients With Hip Fractures: A Randomized Controlled Trial. Anesthesia Analgesia Feb. 2022;134(2):400–9. 10.1213/ane.0000000000005778 . Dexter F, Epstein RH, Titler SS. Larger anesthesia practitioner per operating room ratios are needed to prevent unnecessary non-operative time than to mitigate patient risk: A narrative review. J Clin Anesth Sep. 2024;96:111498. 10.1016/j.jclinane.2024.111498 . Hallet J, Jerath A, d'Empaire PP, et al. Familiarity of the Surgeon-Anesthesiologist Dyad and Major Morbidity After High-Risk Elective Surgery. JAMA Surg Jul. 2025;1(7):772–81. 10.1001/jamasurg.2025.1386 . Chong SE, Mohd Nikman A, Saedah A, et al. Real-time ultrasound-guided paramedian spinal anaesthesia: evaluation of the efficacy and the success rate of single needle pass. Br J Anaesth May. 2017;1(5):799–801. 10.1093/bja/aex108 . Ravi PR, Naik S, Joshi MC, Singh S. Real-time ultrasound-guided spinal anaesthesia vs pre- procedural ultrasound-guided spinal anaesthesia in obese patients. Indian J Anaesth May. 2021;65(5):356–61. 10.4103/ija.IJA_446_20 . Chin KJ. Recent developments in ultrasound imaging for neuraxial blockade. Curr Opin Anaesthesiol Oct. 2018;31(5):608–13. 10.1097/aco.0000000000000634 . Soni NJ, Franco-Sadud R, Schnobrich D, et al. Ultrasound guidance for lumbar puncture. Neurol Clin Pract Aug. 2016;6(4):358–68. 10.1212/cpj.0000000000000265 . Park SK, Yoo S, Kim WH, Lim YJ, Bahk JH, Kim JT. Ultrasound-assisted vs. landmark-guided paramedian spinal anaesthesia in the elderly: A randomised controlled trial. Eur J Anaesthesiol Oct. 2019;36(10):763–71. 10.1097/eja.0000000000001029 . Chen L, Huang J, Zhang Y, et al. Real-Time Ultrasound-Guided Versus Ultrasound-Assisted Spinal Anesthesia in Elderly Patients With Hip Fractures: A Randomized Controlled Trial. Anesth Analg Feb. 2022;1(2):400–9. 10.1213/ane.0000000000005778 . Elsharkawy H, Maheshwari A, Babazade R, Perlas A, Zaky S, Mounir-Soliman L. Real-time ultrasound-guided spinal anesthesia in patients with predicted difficult anatomy. Minerva Anestesiol May. 2017;83(5):465–73. 10.23736/s0375-9393.16.11610-4 . Ökmen K, Yıldız DK. Landmark-guided versus Real-time Ultrasound-guided Combined Spinal-epidural Anesthesia Techniques: Paramedian Sagittal Oblique and Transverse Interlaminar Approach. J Med Ultrasound Jan-Mar. 2024;32(1):55–61. 10.4103/jmu.jmu_22_23 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 08 Feb, 2026 Editor assigned by journal 30 Jan, 2026 Editor invited by journal 30 Jan, 2026 Submission checks completed at journal 29 Jan, 2026 First submitted to journal 29 Jan, 2026 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8687110","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":587745191,"identity":"b8265932-9760-4066-8677-9972c80c1904","order_by":0,"name":"Tianzhu Liu","email":"","orcid":"","institution":"Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Tianzhu","middleName":"","lastName":"Liu","suffix":""},{"id":587745193,"identity":"c288a313-9c2b-4543-99c8-90ca49909374","order_by":1,"name":"Xingxing Sun","email":"","orcid":"","institution":"Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Xingxing","middleName":"","lastName":"Sun","suffix":""},{"id":587745195,"identity":"4dc0914c-fdb8-4614-8cd7-16ced8f93ce7","order_by":2,"name":"Yong Liu","email":"","orcid":"","institution":"Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Yong","middleName":"","lastName":"Liu","suffix":""},{"id":587745196,"identity":"69335f68-4544-4e94-b8bb-fda5cdbdebc2","order_by":3,"name":"Wei Mei","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAt0lEQVRIiWNgGAWjYJCCAx8bIAwJorUcnAnUwkOSFmZekrQYXDt88LDtjsP29gzMB2/zMNjlEdZyOy3hcO6Zw4k9DGzJ1jwMycUEtZjdzjE4nNt2OIGHgcdMmofhQGIDYS35Hw5bth2252Hg/0aslhyGw4xthxl7GHjYiNNifzvN4GBvW3piz2E2Y8s5BsmEtUjOTn784WebtT17e/PDG28q7AhrQQBmEGFAvPpRMApGwSgYBXgAAMsEOrOLnHX6AAAAAElFTkSuQmCC","orcid":"","institution":"Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","correspondingAuthor":true,"prefix":"","firstName":"Wei","middleName":"","lastName":"Mei","suffix":""}],"badges":[],"createdAt":"2026-01-24 13:39:58","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8687110/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8687110/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102553380,"identity":"8c2cdd4d-d7ca-4759-96a3-cf64e9a8ee53","added_by":"auto","created_at":"2026-02-13 01:13:05","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":428050,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eProcedure of RT-SA and Balance of Covariates or Their Effects. \u003c/strong\u003e(A) Real-time ultrasound localization. (B) Real-time ultrasound-guided spinal anesthesia. SP, spinal process. VP, vertebral plate. (C) Covariates balance before and after PSM matching. (D) RT-SA and covariates effects on DTS.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8687110/v1/2cee2e860a437be9cd06f78c.png"},{"id":102553381,"identity":"5fad1a9f-52f0-436d-9ce7-35ba4a0ed332","added_by":"auto","created_at":"2026-02-13 01:13:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":945221,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8687110/v1/19505ec4-eee4-496f-a75d-112754fcbdfa.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Real-time ultrasound-guided vs. landmark-guided spinal anesthesia for scheduled cesarean delivery and door-to-skin incision time: a retrospective study (2019-2024)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSpinal anesthesia has been widely adopted in cesarean section procedures due to its ability to avoid systematic medication while ensuring the safety of both the mother and the fetus\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. However, anatomical landmark-based neuraxial block is insufficient for patients with abnormal spinal structure or the elderly\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Pre-procedure ultrasonic assistance improves spinal anesthesia performance, with a first-pass success rate of 85.7% and reduced number of attempts, while real-time ultrasound-guided spinal anesthesia (RT-SA) achieves a success rate of up to 95.2%\u003csup\u003e4,5\u003c/sup\u003e. However, despite these advantages, the extent to which RT-SA technology can accelerate the turnover of cesarean sections and improve operating room efficiency remains a critical consideration for its practical implementation. Chen LY et al have shown that ultrasound-assisted localization before needle puncture has more time-saving effect than RT-SA in elderly patients\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, highlighting the need to investigate the RT-SA\u0026rsquo;s impact on delaying non-operative time in obstetric surgeries\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAmong RT-SA approaches, the parasagittal approach is widely used for passing fewer ligaments and enhancing intraspinal structure visibility\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. It benefits complex cases such as obese and abnormal anatomy by reducing procedural complexity and improving success rate and safety\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e, but its technical difficulty necessitates time-efficiency research for clinical practice\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Herein, we conducted a single-center retrospective cohort study to verify the impact of this technique and associated demographic characteristics on DTS (the time from patients\u0026rsquo; entry to skin incision).\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThis was a single-center retrospective study. We were authorized by Tongji Hospital Ethics Review Committee (TJ-IRB202410047) on October 15, 2024, and registered on ClinicalTrials.gov (NCT06656793) on October 23, 2024. We conducted a retrospective review of the electronic medical records (EMR) of patients who received RT-SA performed by experienced anesthesiologists between January 1, 2019 and May 29, 2024. The initial population was determined from the EMR software (DoCare v5.0). Only parturients with scheduled cesarean section were included in this study. Finally, we evaluated the effect of RT-SA on cesarean delivery DTS in 928 patients (371 in RT-SA group, 557 in LM-SA group). Statistical analyses were performed in R (4.5.1) using MatchIt, dplyr, and readxl packages.\u003c/p\u003e \u003cp\u003eKey variables included the primary outcome DTS, and covariates (age, BMI, ASA classification [Ⅰ-Ⅲ; with level Ⅱ as the reference]). Propensity scores (PS) were estimated via logistic regression incorporating the interaction term of age and BMI. 1:1 nearest neighbor propensity score matching (PSM) was conducted without replacement, with a caliper of 0.2 standard deviations (SD) of the logit-transformed PS.\u003c/p\u003e \u003cp\u003eAfter PSM, the matched dataset was extracted. Covariate balance before and after matching was assessed using standardized mean differences (SMD) with a threshold of SMD\u0026thinsp;\u0026lt;\u0026thinsp;0.1 considered as adequate balance, via the bal.tab function from the cobalt package. For inferential statistics on the matched data (paired design due to 1:1 matching). Continuous variables (age, BMI, DTS) were compared using paired t-tests. The ordered categorical variable (ASA classification) was compared using the paired Wilcoxon signed-rank test. Descriptive statistics were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD for continuous variables and numbers (percentages) for categorical variables.\u003c/p\u003e \u003cp\u003eFor continuous variables including age, BMI, and dts, descriptive statistics were presented as Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;Standard Deviation, with the Shapiro-Wilk test used to assess normality; for inferential statistics, the paired t-test was applied if the data met the normality assumption in a paired design, while the paired Wilcoxon signed-rank test was used when normality was not satisfied, and in an independent design, the independent samples t-test was adopted for normally distributed data and the Mann-Whitney U test for non-normally distributed data. For the categorical variable (ASA classification), descriptive statistics were expressed as frequency and percentage, with the paired Wilcoxon signed-rank test used for inferential statistics in a paired design and the Kruskal-Wallis test for an independent design.\u003c/p\u003e \u003cp\u003eFor the RT-SA group, patients were placed in the lateral position, with ultrasound-guided puncture; after local anesthesia via an 18G needle, a 25G needle was advanced through the 18G needle to the subarachnoid space, and local anesthetic was injected upon confirmation of cerebrospinal fluid outflow (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA-B). For the LM-SA group, patients were in the flexed lateral decubitus position; puncture was localized via Tuffier\u0026rsquo;s line, two distinct pops were felt, subarachnoid injection was proceeded by cerebrospinal fluid outflow.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 928 patients were initially included, with 371 in the RT-SA group and 557 in the LM-SA group. After 1:1 nearest neighbor PSM without replacement (caliper set at 0.2 standard deviations of the logit-transformed propensity score), 271 pairs were successfully matched, resulting in 271 patients in each group (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Post-matching, all covariates achieved adequate balance (SMD\u0026thinsp;\u0026lt;\u0026thinsp;0.1, Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eC). Unmatched RT-SA and LM-SA patients showed significant differences in mean age and BMI (both P\u0026thinsp;\u0026lt;\u0026thinsp;0.0001), but these differences disappeared after matching (P\u0026thinsp;=\u0026thinsp;0.7774 for age, P\u0026thinsp;=\u0026thinsp;0.3757 for BMI), while ASA classification had no significant differences either before (P\u0026thinsp;=\u0026thinsp;0.9966) or after matching (P\u0026thinsp;=\u0026thinsp;0.2698). For the primary outcome DTS, unmatched RT-SA had a mean of 40.8\u0026thinsp;\u0026plusmn;\u0026thinsp;17.3 minutes versus 37.0\u0026thinsp;\u0026plusmn;\u0026thinsp;11.4 minutes in LM-SA (P\u0026thinsp;=\u0026thinsp;0.0032), while post-matching, RT-SA had 41.9\u0026thinsp;\u0026plusmn;\u0026thinsp;18.3 minutes and LM-SA had 37.9\u0026thinsp;\u0026plusmn;\u0026thinsp;13.7 minutes (P\u0026thinsp;=\u0026thinsp;0.0114).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDemographic and propensity score matching data.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"7\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eUnmatched\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eMatched\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDemographic data\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRT-SA\u003c/p\u003e\n \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;371)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLM-SA\u003c/p\u003e\n \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;557)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRT-SA\u003c/p\u003e\n \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;271)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLM-SA\u003c/p\u003e\n \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;271)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge (yr)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026lt;\u0026thinsp;0.0001\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.0\u0026thinsp;\u0026plusmn;\u0026thinsp;17.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.0\u0026thinsp;\u0026plusmn;\u0026thinsp;11.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e0.7774\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBMI (kg / m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026lt;\u0026thinsp;0.0001\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e0.3757\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eASA, n (%)\u003c/p\u003e\n \u003cp\u003eI\u003c/p\u003e\n \u003cp\u003eⅡ\u003c/p\u003e\n \u003cp\u003eⅢ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e145 (39.1)\u003c/p\u003e\n \u003cp\u003e209 (56.3)\u003c/p\u003e\n \u003cp\u003e17 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e216 (36.9)\u003c/p\u003e\n \u003cp\u003e318 (57.1)\u003c/p\u003e\n \u003cp\u003e23 (4.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003e0.9966\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e108 (39.9)\u003c/p\u003e\n \u003cp\u003e151 (55.7)\u003c/p\u003e\n \u003cp\u003e12(4.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e101 (37.3)\u003c/p\u003e\n \u003cp\u003e156 (57.6)\u003c/p\u003e\n \u003cp\u003e14 (5.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003e0.2698\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOverall DTS (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.8\u0026thinsp;\u0026plusmn;\u0026thinsp;17.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.0\u0026thinsp;\u0026plusmn;\u0026thinsp;11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e0.0032\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41.9\u0026thinsp;\u0026plusmn;\u0026thinsp;18.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.9\u0026thinsp;\u0026plusmn;\u0026thinsp;13.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e0.0114\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\"\u003eThe data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD for continuous variables and numbers (percentages) for categorical variables. RT-SA, real-time ultrasound-guided spinal anesthesia; LM-SA, landmark-guided spinal anesthesia; BMI, body mass index; ASA, American Society of Anesthesiologists; DTS, time consumption from patients\u0026rsquo; entry to skin incision; SD, standard deviation.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eUltrasound-guided pencil-point spinal anesthesia has been widely adopted by anesthesiologists due to its visuality and low cost\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. However, anesthesiologists often have mixed attitudes towards it\u003csup\u003e13,14\u003c/sup\u003e. For elderly patients, ultrasound visualization guidance for spinal anesthesia is extremely important as it can avoid multiple attempts. For obese patients, ultrasound-guided spinal anesthesia can significantly improve the first-pass success rate\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. However, some scholars believe that the learning curve associated with the RT-SA technique is often a significant barrier, resulting in longer procedure completion times compared to LM-SA technique\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOur research has confirmed that when PSM effectively balance baseline covariates (age, BMI, ASA), ensuring the DTS difference is attributable to the technique itself. The RT-SA technique is indeed more time-consuming than the LM-SA technique. The potential reasons may include the need for the operator to perform aseptic preparation of the probe, the additional time required to accurately identify the needle tip and target location on the ultrasound image, and the necessity of real-time trajectory tracking. On the other hand, our research has found that there is only an average difference of 4 minutes in DTS between RT-SA and LM-SA. This difference is almost negligible in the nearly 40-minute anesthesia preparation time, especially for patients with unexpected or anticipated difficulties in spinal puncture\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. The longer 4-minute duration is not a hindrance for experienced RT-SA technique users. However, at the current stage, LM-SA seems to be a better choice for time-sensitive patients. Future prospective RCTs are needed to validate findings.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe need to make some efforts in the training strategy of the RT-SA technology, especially in terms of process optimization, innovative technical training methods, and new training equipment such as artificial intelligence devices and deep learning-assisted course learning\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. For elective cesarean section surgeries, although a 4-minute difference may not have clinical significance, it can still indicate that we urgently need to popularize the RT-SA technology for reducing number of attempts and improving first-time success rate, so that it can be mastered and proficiently applied by more anesthesiologists, achieving time efficiency comparable to or even surpassing that of LM-SA,\u003csup\u003e16\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eRT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSA real-time ultrasound-guided spinal anesthesia\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eLM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSA landmark-guided spinal anesthesia\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eDTS door\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eto-skin incision time\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":" \u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003eWe were authorized by Tongji Hospital Ethics Review Committee (TJ-IRB202410047) on October 15, 2024, and registered on ClinicalTrials.gov (NCT06656793) on October 23, 2024. This study was conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. Informed consent was exempted by the ethics committee due to the use of anonymized, de-identified routine clinical data with no direct participant contact, in line with the 1964 Declaration of Helsinki and its amendments. Strict data privacy and confidentiality protocols were followed in all study stages.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompeting Interests\u003c/strong\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis work was supported by Chen xiaoping Foundation for the development of science and technology of Hubei province (Nos.CXPJJH125001-2558; Tianzhu Liu) and National Natural Science Foundation of China (Nos.82471289; Wei Mei).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eStudy conception/design: Wei Mei.Data acquisition: Yong Liu, Xingxing Sun.Data analysis/interpretation: Tianzhu Liu.Drafting of the manuscript: Tianzhu Liu, Wei Mei.Critical revision of the manuscript for important intellectual content: all authors.Statistical analysis: Tianzhu Liu.Administrative, technical, or material support: Wei Mei.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe extend our heartfelt gratitude to our partners and the engineers responsible for the EMR system, for their invaluable support.\u003c/p\u003e\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSingleton ANE, Moorthy BN, Buggy A. 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Landmark-guided versus Real-time Ultrasound-guided Combined Spinal-epidural Anesthesia Techniques: Paramedian Sagittal Oblique and Transverse Interlaminar Approach. J Med Ultrasound Jan-Mar. 2024;32(1):55\u0026ndash;61. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.4103/jmu.jmu_22_23\u003c/span\u003e\u003cspan address=\"10.4103/jmu.jmu_22_23\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"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":"","lastPublishedDoi":"10.21203/rs.3.rs-8687110/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8687110/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Real-time ultrasound can facilitate spinal anesthesia. However, it remains uncertain whether this technique prolongs the time for parturients entry into the operating room to skin incision compared with the landmark-guided method. We conducted a retrospective, propensity-score-matched study involving patients who received real-time and landmark-guided spinal anesthesia over a five-year period (2019-2024). Results showed a significantly time reduction from “door” to “skin incision” in the landmark-guided spinal anesthesia group compared to the real-time group (37.9 ± 13.7 minutes vs. 41.9 ± 18.3 minutes, P \u003c 0.05). Both the age, body mass index and American Society of Anesthesiologists classification remained no significant correlation with the time reduction from “door” to “skin incision”.","manuscriptTitle":"Real-time ultrasound-guided vs. landmark-guided spinal anesthesia for scheduled cesarean delivery and door-to-skin incision time: a retrospective study (2019-2024)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-13 01:13:00","doi":"10.21203/rs.3.rs-8687110/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2026-02-08T15:19:29+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-30T16:02:28+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-30T06:42:58+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-29T12:35:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Anesthesiology","date":"2026-01-29T11:58:56+00:00","index":"","fulltext":""}],"status":"published","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}}],"origin":"","ownerIdentity":"9bc10c2b-b04e-4c6f-808c-b58b95b2a85c","owner":[],"postedDate":"February 13th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-02-13T01:13:01+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-13 01:13:00","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8687110","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8687110","identity":"rs-8687110","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}