Surgical humidification (HumiGard™) reduces the number of airborne particles entering an open spine wound

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Abraham, Peter R. Riordan, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9708096/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Surgical site infection remains a serious postoperative complication following orthopedic spine surgery. Current preventative strategies aim to minimize airborne particle contamination within the operating room theatre; however additional measures have been investigated to further lower infection risk. Surgical humidification (F&P HumiGard ™ ) is designed to provide a warm humidified wound environment, and aims to minimize the effects of tissue cooling and reduce airborne particles from entering the surgical site. This study aims to evaluate the effectiveness of HumiGard to deflect airborne particles under a static wound and during a dynamic simulation of open spine surgery. Methods A cadaveric simulation of a lumbar laminectomy and L4-L5 posterolateral fusion surgery was performed under a conventional laminar downflow system. HumiGard was adhered to the surgical site prior to the incision and airborne particles (0.3 µm to 10 µm) were continuously measured at the wound using an Optical Particle Sizer. Static wound particle counts were assessed using a HumiGard ON/OFF cycling protocol to evaluate the device specific effects of HumiGard on wound particle counts. In addition, particle counts during the surgical procedure were measured. Particle counts under standard care (control) and HumiGard conditions (intervention) were compared using non-parametric statistical analysis. Results Activation of HumiGard produced immediate and pronounced reductions in particle counts under both static wound and procedural conditions. Median airborne particle counts were reduced by 96% compared to control conditions in a static wound (p < 0.0001). Under dynamic open spine surgery, median airborne particle counts were reduced by 72% compared to control conditions (p < 0.0001), excluding particle counts during diathermy use. Conclusion This study demonstrates active deflection of exogenous particles with HumiGard during a static wound and dynamic cadaveric model of open spine surgery. These findings suggest that HumiGard may be a valuable tool to minimize airborne wound contamination and infection risk during orthopedic surgery, in addition to current infection prevention protocols. Surgical humidification Spine surgery Cadaver Airborne particles Infection control Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Surgical site infections (SSI) are a major source of postoperative complications following spine surgery, placing patients at a high risk for pseudoarthrosis, chronic pain and high rates of revisions leading to prolonged hospital stays and elevated healthcare costs [ 1 ] [ 2 ] [ 3 , 4 ]. Depending on the type of spine procedure, infection rates are highly variable ranging between 0.65% to 18%. Surgery related factors such as use of implants, type of surgery performed, and surgical duration play a key role in the development of SSI following spine surgery [ 4 , 5 ]. Substantial advances have been made in reducing the risk of postoperative infections, with contemporary surgical workflows emphasising the importance of both preoperative patient optimisation and operating room (OR) practices in reducing risk of contamination [ 6 – 8 ]. In modern OR’s, use of surgical masks, gowns, laminar airflow systems, HEPA-filtered air supply and ultraviolet light decontamination of the surgical theatre are utilized to decrease risk of SSI [ 6 , 9 ]. With these measures the risk of airborne contamination has significantly decreased, highlighting the importance of OR protocols to minimize infection risk. However, these systems often function as a whole room intervention at a distance from the surgical field, and are vulnerable to airflow disruptions caused by personnel, instrumentation and overhead equipment within the OR [ 10 , 11 ]. While endogenous sources of contamination such as bacteria derived from the patient’s own body also exist, the risk of SSI and source of surgical wound contamination has been shown to be strongly correlated with the number of exogenous airborne particles present in the surgical environment [ 12 – 15 ]. Evidence from orthopedic wounds have suggested that 98% of bacteria recovered from wounds originate directly or indirectly from the theatre air [ 16 ]. Active air sampling studies performed in clean or clean-contaminated elective surgical procedures have also shown a high genetic link between intraoperative airborne bacteria within the OR and bacteria isolated from SSI’s [ 13 ]. Furthermore, a multicenter randomized control trial of hip and knee replacements by the UK Medical Council has shown a dose response relationship between airborne bacterial concentrations and deep joint sepsis [ 17 ]. The source of these airborne pathogens (0.02–10 um) within the OR can vary and may enter the surgical site directly from the OR air or be indirectly transferred into the wound through surgical equipment, surgeons’ hands and OR staff [ 9 ] [ 16 ]. The number of operating room staff, tissue manipulation, use of surgical instrumentation, and activity levels have been shown to be associated with increased airborne bacterial counts [ 18 ]. In addition, observational studies from orthopedic theatres have shown each additional personnel increases colony forming units (CFU) at the surgical site by 13%, while leaning over the surgical field can increase direct airborne contamination 27-fold [ 9 , 10 ]. Thus, interventions to minimize airborne contamination at the surgical wound may have important implications for infection risk. Experimental studies simulating open cavity wounds have investigated the use localized upward positive pressure systems applied at the wound interface to reduce entry of airborne particles [ 19 – 21 ]. In a wound cavity model, introduction of ultraclean air from the wound was associated a significant reduction in median wound particle counts [ 21 ]. The use of surgical humidification therapy has also been investigated as a strategy to minimize airborne particle contamination and is designed to maintain both physiological conditions and deflect airborne particles away from the surgical site [ 22 , 23 ]. Computational fluid dynamic and benchtop simulations have shown that the use of localized humidified flow of carbon dioxide gas (CO 2 ) into the surgical wound can reduce particle entry to surgical wound cavities by > 90% [ 19 , 20 ]. While in a cadaver simulation of hip arthroplasty, the Fisher & Paykel HumiGard™ Surgical Humidification system created a positive pressure zone over the surgical wound and reduced median particle counts by 61% compared to control conditions without HumiGard [ 23 ]. Given the dynamic nature of orthopedic surgeries with each procedure differing in anatomy, patient positioning and surgical technique, this study aimed to investigate the effects of HumiGard in an open spine surgery model. We hypothesize that using HumiGard at the surgical wound would reduce airborne particle counts in a cadaver simulation of open spine surgery. Methods Study Design This study was conducted at the University of Auckland in the Human Anatomy lab (Department of Anatomy and Medical Imaging). All tissue donated was obtained with informed consent to the University of Auckland in accordance with the Human Tissue Act. Study was reviewed and approved by the Human Tissue Ethics Committee. To simulate standard operating room conditions, all experiments were conducted in a Cleanroom tent (bioBUBBLE, Colorado, USA), which generates a downflow of 0.22 m/s. To reduce sampling time and capture a sufficient number of airborne particles, downflow was not filtered. Although a greater number of particles are captured per second, aaccording to stokes law, particles of the same size follow airflow patterns similarly regardless of their concentration. Therefore the deflection mechanism investigated in this study would accurately represent the proportional reduction of particles observed in standard OR conditions [ 21 ]. One fresh frozen human cadaver (male, 78 years) was used to simulate a lumbar laminectomy and L4-L5 posterolateral fusion and bought to room temperature prior to the beginning of the surgery. Surgical set up and equipment utilized followed the surgeon’s routine practice and was unaffected by this study. Procedure Particle Counts The primary outcome of this study was to quantify surgical site particles with and without HumiGard during a simulated surgical procedure. The Fisher & Paykel HumiGard™ Surgical Humification System is designed to provide warm humidified air to the surgical site and maintain tissue temperature close to physiological levels (~ 37°C fully saturated). The system uses sterile water and delivers filtered air through a sterile tubing kit, containing a filter which removes 99.99% of particles from airstream, and patient diffuser to the open surgical site (Fig. 1 ). All sterile and non-sterile components were set up in accordance with device user instructions while the cadaver was prepared for surgery. The sterile tubing kit and diffuser were set up within the surgical field, while the flow source, non-sterile tubing kit and humidifier were set up by an assistant outside this field. The surgical site was then marked, and a Ioban-2-drape (3M) was applied. The diffuser was placed centrally over the marked incision to provide an even and consistent flow of sterile air over the surgical wound. The diffuser remained adhered to the surgical site throughout the duration of the procedure (Fig. 2 ). To quantify the number of airborne particles within the surgical wound, a sterile sampling tube was affixed at the apex of the diffuser. A particle counter (Optical Particle Sizer 3330; TSI, Minnesota, USA) drew in air through the sterile tube at a rate of 1L/min and enumerated particles ranging in diameter between 0.3 µm and 10 µm. The sampling flow rate of the particle counter does not interfere with the flow rate of the HumiGard therapy (25L/min) or alter particle dynamics at the wound site. Particle counting of the surgical wound with HumiGard turned OFF (control) was performed for 5 minutes prior to the beginning of the surgical procedure. HumiGard was then turned ON (HumiGard intervention) for 1 minute before incision was made and remained ON during the lumbar laminectomy and L4-L5 posterolateral fusion surgery simulation. At the end of surgery, HumiGard was turned OFF (control) and a 5 minute particle count was performed. Static Wound Particle Counts This study also aimed to assess the effectiveness of HumiGard under static wound conditions, where there is minimal interaction of surgical tools, staff and tissue manipulation at the surgical site. These conditions aimed to examine the device specific effect of HumiGard on exogenous airborne particle concentrations at the surgical wound in the absence of airflow disruption from in-wound movement. Following the surgical procedure baseline particle counts were conducted for 2 minutes within the surgical wound. HumiGard remained OFF for an additional 2 minutes and was turned ON for 2 minutes. This ON/OFF cycling protocol was repeated to quantify surgical wound particles counts with HumiGard ON and OFF and evaluate the immediacy, reversibility and stability of HumiGard on exogenous particles counts (Fig. 3 A). Statistical Analysis Raw particle counts were enumerated every 10 seconds and summed. Particle counts were tested for normality with the Shapiro-Wilk test and found to be not normally distributed. Comparison of median particle counts between the control and HumiGard group were conducted using the Mann-Whitney test (median ± 95% confidence interval (CI) are displayed). Counts observed during the HumiGard ON/OFF experiment and surgical procedure were visualised using a time series plot. For visualisation purposes the time series plot of the surgical procedure was log-transformed. Control particle counts during the surgical procedure were analysed using counts taken during the 5-minute period before HumiGard was turned ON and after HumiGard was turned OFF. Particle counts taken during diathermy use were excluded from from HumiGard particle count analysis. Statistical analyses were performed using GraphPad Prism (version 10.4.1 for Windows, GraphPad Software, MA, USA). Statistical significance was defined as p < 0.05. Results Static Wound Particle Counts Static wound particle counts were conducted at the end of the surgical procedure to assess the effect of HumiGard on wound particle contamination, in the absence of surgeon, instrument or tissue movement that could disrupt positive pressure airflow at the surgical wound. Baseline particle counts with HumiGard turned OFF were taken for 2 minutes at the beginning of the experiment (Fig. 3 A). Figure 3 A shows that when HumiGard was turned ON, particle counts rapidly decreased from 415 to 3 particles (10 second sum). Following 2 minutes of HumiGard turned ON, HumiGard was turned OFF and particle counts rapidly increased from 53 to 244 particles (10 second sum). Figure 3 B shows the use of HumiGard significantly reduced median particle counts at the surgical wound by 96% from HumiGard OFF levels (p < 0.0001). The median particle count with HumiGard OFF was 393 per 10 seconds (95% CI: 384 to 403). Median particle counts with HumiGard ON was 16 per 10 seconds (95% CI: 12 to 26). Procedure Particle Counts Particle counts at the surgical wound were also assessed during a simulation of a lumbar laminectomy and L4-L5 posterolateral fusion surgery (Fig. 4 ). Key procedure events are highlighted in Fig. 4 . Particle counts were measured continuously prior to surgical site opening until 5 minutes after the end of the procedure. HumiGard was turned ON 5 minutes into the procedure (before incision), resulting in a decrease of particle counts from 592 to 0 particles (10 second sum). Particle counts rapidly increased with the use of diathermy at 6 minutes and 30.5 minutes into the procedure, resulting in a peak particle count of > 100,000 particles (10 second sum). At the end of the surgical procedure, HumiGard was turned OFF resulting in an increase in particle counts from 102 to 398 particles (10 second sum). Total procedure time was 65.1 minutes. Figure 5 shows the use of HumiGard during the surgical procedure significantly reduced median particle counts at the surgical site by 72% from control levels (p < 0.0001). The median particle counts under control conditions was 478 particles per 10 seconds (95% CI: 443 to 527). Median particle counts with HumiGard was 133 particles per 10 seconds (95% CI: 109 to 208). Note that particle counts during diathermy use (Fig. 4 ) were excluded from analysis, because the use of diathermy generates endogenous particles within the surgical site, which HumiGard is not designed deflect. Discussion Airborne contamination can occur as a result of direct deposition or indirect transfer of airborne particles into the surgical wound[ 14 , 15 ]. In this study, HumiGard use resulted in a significant reduction in surgical site particle counts during both a static open wound and dynamic surgical spine procedure. These findings are consistent with previous investigations, that showed HumiGard establishes a localised positive pressure zone to deflect airborne particulates across different open surgical procedures/sites [ 20 , 23 ]. Because airborne particles within the OR may act as carriers for pathogenic microorganism, interventions aimed at minimising surgical wound exposure to airborne particles may be a clinically relevant strategy for reducing SSI risk and improve wound healing in orthopaedic surgeries. In this study standard OR conditions were simulated under laminar downflow to investigate HumiGard particle deflection performance under both static and dynamic wound conditions. Under static conditions, when HumiGard was turned ON, particle counts within the wound dropped to levels close to 0 and immediately rose when HumiGard was turned OFF (Fig. 3 A). The use of the HumiGard system significantly reduced median particle counts by 96% within the surgical site, highlighting the effectiveness of the HumiGard system in reducing airborne contaminants at the wound interface (Fig. 3 B). This has been observed in other simulated open wound studies where the addition of local wound ventilation was associated with reduction in particle counts within the wound cavity [ 21 ] [ 20 ] [ 19 ]. Kokhanenko et al. have also demonstrated that the extent of reduction may vary depending on particle size and flow characteristics, where CO 2 insufflation in an abdominal surgery model being found to reduce particles < 5 µm by 1000 times, while larger particles up to 15 µm were reduced up to 20 times [ 20 ]. Notably, even under traditional laminar flow systems which are designed to dilute and remove airborne particles and microorganisms from the OR, elevated particle counts were still observed in the absence of localised intervention [ 7 ] [ 6 ]. Potential sources of contamination, such as surgical lights and equipment, movement of surgical personnel, frequency of doors opening can all influence air turbulence and contaminant distribution within the OR. Such sources and physical obstructions within the OR can disrupt the airflow pathway between the downflow systems and wound [ 18 ] [ 10 ] [ 11 ]. This highlights that airborne wound contamination can still occur despite routine controls and minimal activity surrounding the surgical site, thus underscoring the challenge in maintaining a clean operative field. Activation of HumiGard produced immediate and pronounced reductions in surgical site particle counts demonstrating the potential value for localised preventative strategies in minimising wound contamination with the OR. In addition to assessing HumiGard effects under a static wound model, particle counts at the surgical site during a simulated open spine procedure was conducted to replicate key intraoperative steps observed in clinical practice (Fig. 4 ). In this study use of HumiGard was associated with a reduction in particle counts during surgery compared to baseline control levels (HumiGard OFF) (Figs. 4 and 5 ). Median particle counts were significantly reduced by 72% compared to control levels (Fig. 5 ). A significant increase in counts was observed with the use of diathermy, which has been shown to produce the highest aerosol yield during orthopaedic surgery [ 24 ]. These results were excluded from procedure particle counts as HumiGard is not designed to defect endogenous particles from the wound, however this does highlight the fluctuation in particle counts during different timepoints and stages of open spine surgery. Frequent instrument use and tissue manipulation seen in Fig. 4 have the potential to disrupt local airflow and alter the levels of endogenous and exogenous particles in the surgical wound. These findings are consistent with a cadaveric hip arthroplasty experiment which demonstrated a 61% reduction in median particle counts compared to control conditions with the use of HumiGard [ 23 ]. However open spine procedures present distinct anatomical differences and surgical workflows, which typically involves varied operative durations and instrument use [ 25 ] [ 26 ]. While the use of HumiGard on particle deflection has not been previously investigated in an open spine surgery, the use of a localised air barrier system has demonstrated a significant reduction in median particle counts by 37% in patients undergoing instrumented spine procedures [ 12 ]. Furthermore, all implant infections were observed in control group patients, with no infections reported in the intervention group suggesting that strategies aimed at preventing exogenous wound contamination may reduce infection risk in spine surgery. Therefore, despite activity related fluctuations, an overall reduction in wound level particle burden is observed supporting the protective effects of HumiGard even under conditions of heightened intraoperative activity. The observed reduction in particle counts within an open spine procedure may be clinically significant given the dynamic nature of spine surgery. Frequent instrument use and tissue manipulation has the potential to disrupt airflow and pressure gradients created within the standard OR, which has been shown to be correlated with an increase in infection risk [ 1 , 10 ]. Importantly infection risk in spine procedures is variable, with both surgical approach and procedure type being shown to influence infection rates. For example, an increase in instrument and implant use during open spine surgery has been shown to increase SSI risk by up to 28%, while fusion surgeries have a 33% increase in rate of SSIs [ 5 ]. The reasons for these differences may in part be related to an increase in surgical site exposure, longer operating times, extensive soft tissue dissection and retraction, and increased blood loss which is commonly associated with instrumented spine procedures [ 26 ] [ 4 ]. Together these factors underscore the increased vulnerability of the surgical site to infection and highlight the potential role of HumiGard as a protective strategy during open spine surgery. Importantly the effects of HumiGard extend beyond particle deflection. HumiGard has also been shown to reduce intraoperative tissue cooling by delivering warm humidified air to the surgical site as observed in a human randomised control trial in open spine surgery [ 22 ]. The maintenance of humidity can reduce tissue desiccation and mechanical irritation, which may limit local inflammation and support immune defence mechanisms following surgery [ 27 ] [ 22 , 28 ]. Collectively the physiological effects alongside the reduction in number of particles entering the surgical wound may lower the overall bacterial exposure and increase resistance of the patient to infection and contribute to a reduced risk of SSI. Although bacterial contamination was not directly assessed in this study, infection risk is shown to be increased above defined bacterial concentration thresholds [ 12 , 14 ]. However, it is important to note that infection risk is also influenced by other factors such as host resistance, operative duration and tissue exposure. The way in which these factors influence infection risk was not evaluated, nevertheless the findings of this study suggest the use of HumiGard may play a role in reducing the bacterial load within the surgical site. Studies have demonstrated significant correlations between number of airborne particles, CFU and risk of SSI [ 29 ] [ 12 – 14 , 17 ]. While no universally recognized standard for safe CFU density is recommended, it is generally accepted that airborne bacterial density under laminar flow should remain less than 10 CFU/m 3 , with levels no more than 1 CFU/m 3 recommended to eliminate infection risk [ 17 ] [ 30 ]. Indeed, findings from Harp and colleagues have supported this threshold whereby maintaining particle counts below 450 microbe carrying particle (MCP)/m 2 (equivalent to 10 CFU/m 3 ) within the sterile field, was associated with an observed SSI rate of 0% during a joint arthroplasty [ 29 ]. Localised directed airflow devices were found to reduce airborne particulate and bacterial contamination from a mean of 12 CFU/m 3 vs. 2 CFU/m 3 per 10-minute sampling during a total hip arthroplasty [ 31 ]. Furthermore, density of airborne CFU at the incision site in patients undergoing total hip arthroplasty, instrumented spine procedure or vascular bypass graft implantation were found to be significantly related to the incidence implant infection [ 12 ]. Notably CFU densities were found to be 4 times greater in procedures with implant infections vs. no infection [ 12 ] Overall, these findings suggest particle concentration may be relevant indicators of contamination risk, thus understanding how thresholds may impact this risk may be useful in predicting infection outcomes. Future studies should investigate the pathogenic nature of particles within the surgical wound and OR in live patient orthopaedic procedures to fully evaluate the effectiveness of HumiGard in minimising SSI risk. Although this study assessed a dynamic open spine surgery procedure in a simulated OR environment, the experiment was conducted using a single specimen cadaveric model, which may limit generalisability to live surgical settings. Furthermore, these experiments were conducted under unfiltered downflow which increases the concentration of airborne particles compared to a standard OR. This was done to demonstrate the effectiveness of the deflection mechanism and increase the temporal resolution of each procedural step. A greater number of particles may be sampled over the surgical procedure in this study, however the particles sizes sampled are consistent with those found in ventilated OR (particle sizes between 0.3 µm and 10 µm) [ 32 ]. Conclusion In conclusion, this study shows that HumiGard significantly reduced surgical site particle counts during a static open wound and dynamic cadaver simulation of an open spine procedure. HumiGard use did not interrupt the surgeon’s workflow or surgical manipulation of the tissue and significantly reduced surgical wound particle counts. While this cadaveric study did not assess the impact of HumiGard on infection rates, these findings suggest that HumiGard may serve as a valuable tool, in addition to current infection prevention measures, to minimise the risk of airborne wound contamination during open spine surgery. 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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-9708096","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":639959355,"identity":"f8d21547-e976-4cb3-a307-6b263939105e","order_by":0,"name":"Alpesh Patel","email":"","orcid":"","institution":"Department of Orthopaedics, Middlemore Hospital, Auckland, New Zealand","correspondingAuthor":false,"prefix":"","firstName":"Alpesh","middleName":"","lastName":"Patel","suffix":""},{"id":639959356,"identity":"2809b7da-6cef-4c6c-980b-05e02039ec9f","order_by":1,"name":"Angelina Soh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFklEQVRIie2RsWrDMBBAzwScxaBVxZD8gkLATcGlv3KmIC1uKWTNoKlZAl4D/Yl+QovAk0vppsGDQ8GzRg8dqrgJdJDBY6F6y6HjnqS7A/B4/ioN60MIJgUcp+BJCfZ8tPITwkk0RiFP248GH+o5EFV+pljfk+3boYFNCpfkxanQulozZO1CUi6WObZrWoklg5LDlXQroHNOkalA0iiJ7zqVPQMPaSAVsFfpNOY6F51VbiSpkniFViHttOsV5X6EaVHaialMQp7EcFQoD6FXSrey0Pnk+LHbR8r5xQ7bbK9bmyl5xCq3MtPiYMyXui7sxGiHdVYUPDBmk87Y+0D7EJ1X33OqQpsfqLdMm9+noYs9Ho/nP/MNCX5hB+jYgXIAAAAASUVORK5CYII=","orcid":"","institution":"Fisher \u0026 Paykel Healthcare Ltd, Auckland, New Zealand","correspondingAuthor":true,"prefix":"","firstName":"Angelina","middleName":"","lastName":"Soh","suffix":""},{"id":639959357,"identity":"d8112de6-1446-429b-8cbc-ea99e858817a","order_by":2,"name":"Molly I. Abraham","email":"","orcid":"","institution":"Fisher \u0026 Paykel Healthcare Ltd, Auckland, New Zealand","correspondingAuthor":false,"prefix":"","firstName":"Molly","middleName":"I.","lastName":"Abraham","suffix":""},{"id":639959358,"identity":"c7111570-c657-4f50-8631-bbe9793b151e","order_by":3,"name":"Peter R. Riordan","email":"","orcid":"","institution":"Department of Anatomy with Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand","correspondingAuthor":false,"prefix":"","firstName":"Peter","middleName":"R.","lastName":"Riordan","suffix":""},{"id":639959359,"identity":"9c6ace18-9d6e-4fcc-b789-719c9ce06b2b","order_by":4,"name":"Callum J.T. Spence","email":"","orcid":"","institution":"Fisher \u0026 Paykel Healthcare Ltd, Auckland, New Zealand","correspondingAuthor":false,"prefix":"","firstName":"Callum","middleName":"J.T.","lastName":"Spence","suffix":""}],"badges":[],"createdAt":"2026-05-13 22:26:45","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9708096/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9708096/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109338115,"identity":"f92d9672-45af-4d88-874d-b533d595bdef","added_by":"auto","created_at":"2026-05-15 17:50:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":258885,"visible":true,"origin":"","legend":"\u003cp\u003eDiagrammatic representation of the Fisher \u0026amp; Paykel HumiGard\u003csup\u003eTM \u003c/sup\u003eSurgical Humidification system for use in open spine surgery. Patient diffuser was adhered to the surgical site throughout the duration of the procedure and experiment.\u0026nbsp;\u0026nbsp;\u003c/p\u003e","description":"","filename":"Figures1.png","url":"https://assets-eu.researchsquare.com/files/rs-9708096/v1/8f25275be5acccc9904c9aed.png"},{"id":109405672,"identity":"c85556e4-0cda-44c3-9aff-e0edf8278ce5","added_by":"auto","created_at":"2026-05-17 13:19:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1096302,"visible":true,"origin":"","legend":"\u003cp\u003ePhotograph of the HumiGard patient diffuser and particle counter during a human cadaveric open spine procedure. The patient diffuser adheres around the surgical site up to a maximum incision length of 16cm. Diffuser provides an even and consistent flow and utilises bulk displacement to isolate the surgical site from theatre air. Particle counter draws in air at a rate of 1L/min and counts the number of particles entering the surgical site.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-9708096/v1/affbbc913e28d462eee9ffe3.png"},{"id":109405550,"identity":"313d9084-5214-466e-a624-1a88122db4d4","added_by":"auto","created_at":"2026-05-17 13:18:55","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":238651,"visible":true,"origin":"","legend":"\u003cp\u003eTime course and median particle count (per 10 sec sum) during the HumiGard ON/OFF experiment. (A) Baseline particle counts with HumiGard OFF were recorded for 4 minutes, followed by alternating HumiGard ON and OFF treatments (2-minute duration). Shaded areas (grey) show periods when HumiGard was turned ON. (B) Statistical comparison of median particle counts (± 95% confidence interval) during HumiGard OFF vs. ON conditions were performed using the Mann-Whitney test, ****p\u0026lt;0.0001.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-9708096/v1/3509f8d24ab5de13e4b896cb.png"},{"id":109338117,"identity":"d0ed97c7-0bb5-4ca6-967d-f90433f62e7f","added_by":"auto","created_at":"2026-05-15 17:50:01","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":129253,"visible":true,"origin":"","legend":"\u003cp\u003eTime course of particle counts (per 10 sec sum) during a cadaver simulation of a lumbar laminectomy and L4-L5 posterolateral fusion procedure. HumiGard was turned on prior to incision and turned off at the end of the surgical procedure. Shaded areas (grey) represent periods which were used to analyze procedure particle counts for HumiGard ON quantified in Figure 5.\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9708096/v1/7d5e0644343ec7ebb5dba5a7.jpg"},{"id":109338119,"identity":"54443be8-aed9-409f-9cfc-bde1eb93887b","added_by":"auto","created_at":"2026-05-15 17:50:01","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":46484,"visible":true,"origin":"","legend":"\u003cp\u003eGraph of median particle counts (per 10 sec sum) in control and HumiGard conditions during a cadaver simulation of an open spine procedure. Note that measurements taken during diathermy use were excluded from HumiGard particle count analysis. Statistical comparison of median particle counts (± 95% confidence interval) between control and HumiGard conditions were performed using the Mann-Whitney test, ****p\u0026lt;0.0001.\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9708096/v1/1fbf02cf6f67762c9755fb51.jpg"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eSurgical humidification \u003cstrong\u003e(\u003c/strong\u003eHumiGard™) reduces the number of airborne particles entering an open spine wound\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSurgical site infections (SSI) are a major source of postoperative complications following spine surgery, placing patients at a high risk for pseudoarthrosis, chronic pain and high rates of revisions leading to prolonged hospital stays and elevated healthcare costs [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Depending on the type of spine procedure, infection rates are highly variable ranging between 0.65% to 18%. Surgery related factors such as use of implants, type of surgery performed, and surgical duration play a key role in the development of SSI following spine surgery [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Substantial advances have been made in reducing the risk of postoperative infections, with contemporary surgical workflows emphasising the importance of both preoperative patient optimisation and operating room (OR) practices in reducing risk of contamination [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn modern OR\u0026rsquo;s, use of surgical masks, gowns, laminar airflow systems, HEPA-filtered air supply and ultraviolet light decontamination of the surgical theatre are utilized to decrease risk of SSI [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. With these measures the risk of airborne contamination has significantly decreased, highlighting the importance of OR protocols to minimize infection risk. However, these systems often function as a whole room intervention at a distance from the surgical field, and are vulnerable to airflow disruptions caused by personnel, instrumentation and overhead equipment within the OR [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. While endogenous sources of contamination such as bacteria derived from the patient\u0026rsquo;s own body also exist, the risk of SSI and source of surgical wound contamination has been shown to be strongly correlated with the number of exogenous airborne particles present in the surgical environment [\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Evidence from orthopedic wounds have suggested that 98% of bacteria recovered from wounds originate directly or indirectly from the theatre air [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Active air sampling studies performed in clean or clean-contaminated elective surgical procedures have also shown a high genetic link between intraoperative airborne bacteria within the OR and bacteria isolated from SSI\u0026rsquo;s [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Furthermore, a multicenter randomized control trial of hip and knee replacements by the UK Medical Council has shown a dose response relationship between airborne bacterial concentrations and deep joint sepsis [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The source of these airborne pathogens (0.02\u0026ndash;10 um) within the OR can vary and may enter the surgical site directly from the OR air or be indirectly transferred into the wound through surgical equipment, surgeons\u0026rsquo; hands and OR staff [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The number of operating room staff, tissue manipulation, use of surgical instrumentation, and activity levels have been shown to be associated with increased airborne bacterial counts [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In addition, observational studies from orthopedic theatres have shown each additional personnel increases colony forming units (CFU) at the surgical site by 13%, while leaning over the surgical field can increase direct airborne contamination 27-fold [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Thus, interventions to minimize airborne contamination at the surgical wound may have important implications for infection risk.\u003c/p\u003e \u003cp\u003eExperimental studies simulating open cavity wounds have investigated the use localized upward positive pressure systems applied at the wound interface to reduce entry of airborne particles [\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In a wound cavity model, introduction of ultraclean air from the wound was associated a significant reduction in median wound particle counts [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The use of surgical humidification therapy has also been investigated as a strategy to minimize airborne particle contamination and is designed to maintain both physiological conditions and deflect airborne particles away from the surgical site [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Computational fluid dynamic and benchtop simulations have shown that the use of localized humidified flow of carbon dioxide gas (CO\u003csub\u003e2\u003c/sub\u003e) into the surgical wound can reduce particle entry to surgical wound cavities by \u0026gt;\u0026thinsp;90% [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. While in a cadaver simulation of hip arthroplasty, the Fisher \u0026amp; Paykel HumiGard\u0026trade; Surgical Humidification system created a positive pressure zone over the surgical wound and reduced median particle counts by 61% compared to control conditions without HumiGard [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Given the dynamic nature of orthopedic surgeries with each procedure differing in anatomy, patient positioning and surgical technique, this study aimed to investigate the effects of HumiGard in an open spine surgery model. We hypothesize that using HumiGard at the surgical wound would reduce airborne particle counts in a cadaver simulation of open spine surgery.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design\u003c/h2\u003e \u003cp\u003eThis study was conducted at the University of Auckland in the Human Anatomy lab (Department of Anatomy and Medical Imaging). All tissue donated was obtained with informed consent to the University of Auckland in accordance with the Human Tissue Act. Study was reviewed and approved by the Human Tissue Ethics Committee.\u003c/p\u003e \u003cp\u003eTo simulate standard operating room conditions, all experiments were conducted in a Cleanroom tent (bioBUBBLE, Colorado, USA), which generates a downflow of 0.22 m/s. To reduce sampling time and capture a sufficient number of airborne particles, downflow was not filtered. Although a greater number of particles are captured per second, aaccording to stokes law, particles of the same size follow airflow patterns similarly regardless of their concentration. Therefore the deflection mechanism investigated in this study would accurately represent the proportional reduction of particles observed in standard OR conditions [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. One fresh frozen human cadaver (male, 78 years) was used to simulate a lumbar laminectomy and L4-L5 posterolateral fusion and bought to room temperature prior to the beginning of the surgery. Surgical set up and equipment utilized followed the surgeon\u0026rsquo;s routine practice and was unaffected by this study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eProcedure Particle Counts \u003c/h3\u003e\n\u003cp\u003eThe primary outcome of this study was to quantify surgical site particles with and without HumiGard during a simulated surgical procedure. The Fisher \u0026amp; Paykel HumiGard\u0026trade; Surgical Humification System is designed to provide warm humidified air to the surgical site and maintain tissue temperature close to physiological levels (~\u0026thinsp;37\u0026deg;C fully saturated). The system uses sterile water and delivers filtered air through a sterile tubing kit, containing a filter which removes 99.99% of particles from airstream, and patient diffuser to the open surgical site (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). All sterile and non-sterile components were set up in accordance with device user instructions while the cadaver was prepared for surgery. The sterile tubing kit and diffuser were set up within the surgical field, while the flow source, non-sterile tubing kit and humidifier were set up by an assistant outside this field. The surgical site was then marked, and a Ioban-2-drape (3M) was applied. The diffuser was placed centrally over the marked incision to provide an even and consistent flow of sterile air over the surgical wound. The diffuser remained adhered to the surgical site throughout the duration of the procedure (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo quantify the number of airborne particles within the surgical wound, a sterile sampling tube was affixed at the apex of the diffuser. A particle counter (Optical Particle Sizer 3330; TSI, Minnesota, USA) drew in air through the sterile tube at a rate of 1L/min and enumerated particles ranging in diameter between 0.3 \u0026micro;m and 10 \u0026micro;m. The sampling flow rate of the particle counter does not interfere with the flow rate of the HumiGard therapy (25L/min) or alter particle dynamics at the wound site. Particle counting of the surgical wound with HumiGard turned OFF (control) was performed for 5 minutes prior to the beginning of the surgical procedure. HumiGard was then turned ON (HumiGard intervention) for 1 minute before incision was made and remained ON during the lumbar laminectomy and L4-L5 posterolateral fusion surgery simulation. At the end of surgery, HumiGard was turned OFF (control) and a 5 minute particle count was performed.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eStatic Wound Particle Counts\u003c/h3\u003e\n\u003cp\u003eThis study also aimed to assess the effectiveness of HumiGard under static wound conditions, where there is minimal interaction of surgical tools, staff and tissue manipulation at the surgical site. These conditions aimed to examine the device specific effect of HumiGard on exogenous airborne particle concentrations at the surgical wound in the absence of airflow disruption from in-wound movement. Following the surgical procedure baseline particle counts were conducted for 2 minutes within the surgical wound. HumiGard remained OFF for an additional 2 minutes and was turned ON for 2 minutes. This ON/OFF cycling protocol was repeated to quantify surgical wound particles counts with HumiGard ON and OFF and evaluate the immediacy, reversibility and stability of HumiGard on exogenous particles counts (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA).\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eRaw particle counts were enumerated every 10 seconds and summed. Particle counts were tested for normality with the Shapiro-Wilk test and found to be not normally distributed. Comparison of median particle counts between the control and HumiGard group were conducted using the Mann-Whitney test (median\u0026thinsp;\u0026plusmn;\u0026thinsp;95% confidence interval (CI) are displayed). Counts observed during the HumiGard ON/OFF experiment and surgical procedure were visualised using a time series plot. For visualisation purposes the time series plot of the surgical procedure was log-transformed. Control particle counts during the surgical procedure were analysed using counts taken during the 5-minute period before HumiGard was turned ON and after HumiGard was turned OFF. Particle counts taken during diathermy use were excluded from from HumiGard particle count analysis. Statistical analyses were performed using GraphPad Prism (version 10.4.1 for Windows, GraphPad Software, MA, USA). Statistical significance was defined as p\u0026thinsp;\u003cem\u003e\u0026lt;\u003c/em\u003e\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatic Wound Particle Counts\u003c/h2\u003e \u003cp\u003eStatic wound particle counts were conducted at the end of the surgical procedure to assess the effect of HumiGard on wound particle contamination, in the absence of surgeon, instrument or tissue movement that could disrupt positive pressure airflow at the surgical wound. Baseline particle counts with HumiGard turned OFF were taken for 2 minutes at the beginning of the experiment (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA shows that when HumiGard was turned ON, particle counts rapidly decreased from 415 to 3 particles (10 second sum). Following 2 minutes of HumiGard turned ON, HumiGard was turned OFF and particle counts rapidly increased from 53 to 244 particles (10 second sum). Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB shows the use of HumiGard significantly reduced median particle counts at the surgical wound by 96% from HumiGard OFF levels (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The median particle count with HumiGard OFF was 393 per 10 seconds (95% CI: 384 to 403). Median particle counts with HumiGard ON was 16 per 10 seconds (95% CI: 12 to 26).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eProcedure Particle Counts\u003c/h3\u003e\n\u003cp\u003eParticle counts at the surgical wound were also assessed during a simulation of a lumbar laminectomy and L4-L5 posterolateral fusion surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Key procedure events are highlighted in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Particle counts were measured continuously prior to surgical site opening until 5 minutes after the end of the procedure. HumiGard was turned ON 5 minutes into the procedure (before incision), resulting in a decrease of particle counts from 592 to 0 particles (10 second sum). Particle counts rapidly increased with the use of diathermy at 6 minutes and 30.5 minutes into the procedure, resulting in a peak particle count of \u0026gt;\u0026thinsp;100,000 particles (10 second sum). At the end of the surgical procedure, HumiGard was turned OFF resulting in an increase in particle counts from 102 to 398 particles (10 second sum). Total procedure time was 65.1 minutes.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the use of HumiGard during the surgical procedure significantly reduced median particle counts at the surgical site by 72% from control levels (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The median particle counts under control conditions was 478 particles per 10 seconds (95% CI: 443 to 527). Median particle counts with HumiGard was 133 particles per 10 seconds (95% CI: 109 to 208). Note that particle counts during diathermy use (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) were excluded from analysis, because the use of diathermy generates endogenous particles within the surgical site, which HumiGard is not designed deflect.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAirborne contamination can occur as a result of direct deposition or indirect transfer of airborne particles into the surgical wound[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In this study, HumiGard use resulted in a significant reduction in surgical site particle counts during both a static open wound and dynamic surgical spine procedure. These findings are consistent with previous investigations, that showed HumiGard establishes a localised positive pressure zone to deflect airborne particulates across different open surgical procedures/sites [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Because airborne particles within the OR may act as carriers for pathogenic microorganism, interventions aimed at minimising surgical wound exposure to airborne particles may be a clinically relevant strategy for reducing SSI risk and improve wound healing in orthopaedic surgeries.\u003c/p\u003e \u003cp\u003eIn this study standard OR conditions were simulated under laminar downflow to investigate HumiGard particle deflection performance under both static and dynamic wound conditions. Under static conditions, when HumiGard was turned ON, particle counts within the wound dropped to levels close to 0 and immediately rose when HumiGard was turned OFF (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). The use of the HumiGard system significantly reduced median particle counts by 96% within the surgical site, highlighting the effectiveness of the HumiGard system in reducing airborne contaminants at the wound interface (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB). This has been observed in other simulated open wound studies where the addition of local wound ventilation was associated with reduction in particle counts within the wound cavity [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Kokhanenko et al. have also demonstrated that the extent of reduction may vary depending on particle size and flow characteristics, where CO\u003csub\u003e2\u003c/sub\u003e insufflation in an abdominal surgery model being found to reduce particles\u0026thinsp;\u0026lt;\u0026thinsp;5 \u0026micro;m by 1000 times, while larger particles up to 15 \u0026micro;m were reduced up to 20 times [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Notably, even under traditional laminar flow systems which are designed to dilute and remove airborne particles and microorganisms from the OR, elevated particle counts were still observed in the absence of localised intervention [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Potential sources of contamination, such as surgical lights and equipment, movement of surgical personnel, frequency of doors opening can all influence air turbulence and contaminant distribution within the OR. Such sources and physical obstructions within the OR can disrupt the airflow pathway between the downflow systems and wound [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This highlights that airborne wound contamination can still occur despite routine controls and minimal activity surrounding the surgical site, thus underscoring the challenge in maintaining a clean operative field. Activation of HumiGard produced immediate and pronounced reductions in surgical site particle counts demonstrating the potential value for localised preventative strategies in minimising wound contamination with the OR.\u003c/p\u003e \u003cp\u003eIn addition to assessing HumiGard effects under a static wound model, particle counts at the surgical site during a simulated open spine procedure was conducted to replicate key intraoperative steps observed in clinical practice (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). In this study use of HumiGard was associated with a reduction in particle counts during surgery compared to baseline control levels (HumiGard OFF) (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Median particle counts were significantly reduced by 72% compared to control levels (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). A significant increase in counts was observed with the use of diathermy, which has been shown to produce the highest aerosol yield during orthopaedic surgery [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. These results were excluded from procedure particle counts as HumiGard is not designed to defect endogenous particles from the wound, however this does highlight the fluctuation in particle counts during different timepoints and stages of open spine surgery. Frequent instrument use and tissue manipulation seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e have the potential to disrupt local airflow and alter the levels of endogenous and exogenous particles in the surgical wound. These findings are consistent with a cadaveric hip arthroplasty experiment which demonstrated a 61% reduction in median particle counts compared to control conditions with the use of HumiGard [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. However open spine procedures present distinct anatomical differences and surgical workflows, which typically involves varied operative durations and instrument use [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. While the use of HumiGard on particle deflection has not been previously investigated in an open spine surgery, the use of a localised air barrier system has demonstrated a significant reduction in median particle counts by 37% in patients undergoing instrumented spine procedures [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Furthermore, all implant infections were observed in control group patients, with no infections reported in the intervention group suggesting that strategies aimed at preventing exogenous wound contamination may reduce infection risk in spine surgery. Therefore, despite activity related fluctuations, an overall reduction in wound level particle burden is observed supporting the protective effects of HumiGard even under conditions of heightened intraoperative activity.\u003c/p\u003e \u003cp\u003eThe observed reduction in particle counts within an open spine procedure may be clinically significant given the dynamic nature of spine surgery. Frequent instrument use and tissue manipulation has the potential to disrupt airflow and pressure gradients created within the standard OR, which has been shown to be correlated with an increase in infection risk [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Importantly infection risk in spine procedures is variable, with both surgical approach and procedure type being shown to influence infection rates. For example, an increase in instrument and implant use during open spine surgery has been shown to increase SSI risk by up to 28%, while fusion surgeries have a 33% increase in rate of SSIs [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The reasons for these differences may in part be related to an increase in surgical site exposure, longer operating times, extensive soft tissue dissection and retraction, and increased blood loss which is commonly associated with instrumented spine procedures [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Together these factors underscore the increased vulnerability of the surgical site to infection and highlight the potential role of HumiGard as a protective strategy during open spine surgery. Importantly the effects of HumiGard extend beyond particle deflection. HumiGard has also been shown to reduce intraoperative tissue cooling by delivering warm humidified air to the surgical site as observed in a human randomised control trial in open spine surgery [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The maintenance of humidity can reduce tissue desiccation and mechanical irritation, which may limit local inflammation and support immune defence mechanisms following surgery [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Collectively the physiological effects alongside the reduction in number of particles entering the surgical wound may lower the overall bacterial exposure and increase resistance of the patient to infection and contribute to a reduced risk of SSI.\u003c/p\u003e \u003cp\u003eAlthough bacterial contamination was not directly assessed in this study, infection risk is shown to be increased above defined bacterial concentration thresholds [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. However, it is important to note that infection risk is also influenced by other factors such as host resistance, operative duration and tissue exposure. The way in which these factors influence infection risk was not evaluated, nevertheless the findings of this study suggest the use of HumiGard may play a role in reducing the bacterial load within the surgical site. Studies have demonstrated significant correlations between number of airborne particles, CFU and risk of SSI [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. While no universally recognized standard for safe CFU density is recommended, it is generally accepted that airborne bacterial density under laminar flow should remain less than 10 CFU/m\u003csup\u003e3\u003c/sup\u003e, with levels no more than 1 CFU/m\u003csup\u003e3\u003c/sup\u003e recommended to eliminate infection risk [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Indeed, findings from Harp and colleagues have supported this threshold whereby maintaining particle counts below 450 microbe carrying particle (MCP)/m\u003csup\u003e2\u003c/sup\u003e (equivalent to 10 CFU/m\u003csup\u003e3\u003c/sup\u003e) within the sterile field, was associated with an observed SSI rate of 0% during a joint arthroplasty [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Localised directed airflow devices were found to reduce airborne particulate and bacterial contamination from a mean of 12 CFU/m\u003csup\u003e3\u003c/sup\u003e vs. 2 CFU/m\u003csup\u003e3\u003c/sup\u003e per 10-minute sampling during a total hip arthroplasty [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Furthermore, density of airborne CFU at the incision site in patients undergoing total hip arthroplasty, instrumented spine procedure or vascular bypass graft implantation were found to be significantly related to the incidence implant infection [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Notably CFU densities were found to be 4 times greater in procedures with implant infections vs. no infection [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] Overall, these findings suggest particle concentration may be relevant indicators of contamination risk, thus understanding how thresholds may impact this risk may be useful in predicting infection outcomes. Future studies should investigate the pathogenic nature of particles within the surgical wound and OR in live patient orthopaedic procedures to fully evaluate the effectiveness of HumiGard in minimising SSI risk.\u003c/p\u003e \u003cp\u003eAlthough this study assessed a dynamic open spine surgery procedure in a simulated OR environment, the experiment was conducted using a single specimen cadaveric model, which may limit generalisability to live surgical settings. Furthermore, these experiments were conducted under unfiltered downflow which increases the concentration of airborne particles compared to a standard OR. This was done to demonstrate the effectiveness of the deflection mechanism and increase the temporal resolution of each procedural step. A greater number of particles may be sampled over the surgical procedure in this study, however the particles sizes sampled are consistent with those found in ventilated OR (particle sizes between 0.3 \u0026micro;m and 10 \u0026micro;m) [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, this study shows that HumiGard significantly reduced surgical site particle counts during a static open wound and dynamic cadaver simulation of an open spine procedure. HumiGard use did not interrupt the surgeon\u0026rsquo;s workflow or surgical manipulation of the tissue and significantly reduced surgical wound particle counts. While this cadaveric study did not assess the impact of HumiGard on infection rates, these findings suggest that HumiGard may serve as a valuable tool, in addition to current infection prevention measures, to minimise the risk of airborne wound contamination during open spine surgery.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlgarny S et al (2023) Postoperative Surgical Site Infections in Spine Surgery: Can the Duration of Surgery Predict the Pathogen Spectrum? Vivo 37(4):1688\u0026ndash;1693\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDowdell J et al (2018) Postoperative Spine Infection: Diagnosis and Management. Global Spine J 8(4 Suppl):37s\u0026ndash;43s\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBadia JM et al (2017) Impact of surgical site infection on healthcare costs and patient outcomes: a systematic review in six European countries. J Hosp Infect 96(1):1\u0026ndash;15\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlfin DJ et al (2025) Surgical site infection rate in spine surgery, incidence, and risk factors: a ten-year retrospective cohort review in a developing neurosurgical centre. BMC Surg 25(1):127\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel H et al (2017) Burden of Surgical Site Infections Associated with Select Spine Operations and Involvement of Staphylococcus aureus. Surg Infect (Larchmt) 18(4):461\u0026ndash;473\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDharan S, Pittet D (2002) Environmental controls in operating theatres. J Hosp Infect 51(2):79\u0026ndash;84\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcHugh SM, Hill AD, Humphreys H (2015) Laminar airflow and the prevention of surgical site infection. More harm than good? Surgeon 13(1):52\u0026ndash;58\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNasser R et al (2018) Risk Factors and Prevention of Surgical Site Infections Following Spinal Procedures. Global Spine J 8(4 Suppl):44s\u0026ndash;48s\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eErichsen Andersson A et al (2014) Comparison between mixed and laminar airflow systems in operating rooms and the influence of human factors: experiences from a Swedish orthopedic center. Am J Infect Control 42(6):665\u0026ndash;669\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaylor GJ, Bannister GC (1993) Infection and interposition between ultraclean air source and wound. J Bone Joint Surg Br 75(3):503\u0026ndash;504\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarroll GT, Kirschman DL (2022) Discrete room pressure drops predict door openings and contamination levels in the operating room setting. Perioperative Care Operating Room Manage 29:100291\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDarouiche RO et al (2017) Association of Airborne Microorganisms in the Operating Room With Implant Infections: A Randomized Controlled Trial. Infect Control Hosp Epidemiol 38(1):3\u0026ndash;10\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStauning MA et al (2020) Genetic relationship between bacteria isolated from intraoperative air samples and surgical site infections at a major teaching hospital in Ghana. J Hosp Infect 104(3):309\u0026ndash;320\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSeth Caous J et al (2025) Correlation of airborne bacteria in the operating room with surgical wound contamination and surgical site infection: a systematic review. J Hosp Infect 166:121\u0026ndash;137\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFriberg B, Friberg S, Burman LG (1999) Correlation between surface and air counts of particles carrying aerobic bacteria in operating rooms with turbulent ventilation: an experimental study. J Hosp Infect 42(1):61\u0026ndash;68\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWhyte W et al (1992) The relative importance of the routes and sources of wound contamination during general surgery. II. Airborne. J Hosp Infect 22(1):41\u0026ndash;54\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLidwell OM et al (1982) Effect of ultraclean air in operating rooms on deep sepsis in the joint after total hip or knee replacement: a randomised study. Br Med J (Clin Res Ed) 285(6334):10\u0026ndash;14\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuehl M et al (2025) The Association Between OR Traffic and Airborne Microbial Counts During Two Types of Abdominal Surgeries. Aorn j 121(5):344\u0026ndash;360\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaumann M, Cater JE (2018) The Effect of Heated CO2 Insufflation in Minimising Surgical Wound Contamination During Open Surgery. Ann Biomed Eng 46(8):1101\u0026ndash;1111\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKokhanenko P et al (2017) Carbon dioxide insufflation deflects airborne particles from an open surgical wound model. J Hosp Infect 95(1):112\u0026ndash;117\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePersson M, van der Linden J (2004) Wound ventilation with ultraclean air for prevention of direct airborne contamination during surgery. Infect Control Hosp Epidemiol 25(4):297\u0026ndash;301\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eManners S et al (2025) Surgical humidification (HumiGard\u0026trade;) improves tissue temperature during open spinal surgery: a first in-human randomised controlled trial. J Spine Surg 11(4):913\u0026ndash;921\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbraham MI et al (2026) Preliminary cadaver study of Surgical Humidification (HumiGard\u0026trade;) demonstrating reduced intra-wound particle counts during total hip arthroplasty. J Hosp Infect 167:156\u0026ndash;162\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHamilton V et al (2023) Diathermy and bone sawing are high aerosol yield procedures. Bone Joint Res 12(10):636\u0026ndash;643\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMensah EO et al (2024) \u003cem\u003eChallenges in Contemporary Spine Surgery: A Comprehensive Review of Surgical, Technological, and Patient-Specific Issues.\u003c/em\u003e J Clin Med, 13(18)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLazennec JY et al (2011) Infections in the operated spine: update on risk management and therapeutic strategies. Orthop Traumatol Surg Res 97(6 Suppl):S107\u0026ndash;S116\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBinda MM et al (2006) Effect of desiccation and temperature during laparoscopy on adhesion formation in mice. Fertil Steril 86(1):166\u0026ndash;175\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMargraf A et al (2020) Systemic Inflammatory Response Syndrome After Surgery: Mechanisms and Protection. Anesth Analg 131(6):1693\u0026ndash;1707\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarp JH (2023) Observational study of sterile field bioburden levels during orthopedic arthroplasty surgery in operating rooms complying with current United States ventilation specifications. Am J Infect Control 51(7):758\u0026ndash;764\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWhyte W et al (1983) Suggested bacteriological standards for air in ultraclean operating rooms. J Hosp Infect 4(2):133\u0026ndash;139\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStocks GW et al (2011) Directed air flow to reduce airborne particulate and bacterial contamination in the surgical field during total hip arthroplasty. J Arthroplasty 26(5):771\u0026ndash;776\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChauveaux D (2015) Preventing surgical-site infections: measures other than antibiotics. Orthop Traumatol Surg Res 101(1 Suppl):S77\u0026ndash;83\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Fisher \u0026 Paykel Healthcare (New Zealand)","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Surgical humidification, Spine surgery, Cadaver, Airborne particles, Infection control ","lastPublishedDoi":"10.21203/rs.3.rs-9708096/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9708096/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eSurgical site infection remains a serious postoperative complication following orthopedic spine surgery. Current preventative strategies aim to minimize airborne particle contamination within the operating room theatre; however additional measures have been investigated to further lower infection risk. Surgical humidification (F\u0026amp;P HumiGard\u003csup\u003e\u0026trade;\u003c/sup\u003e ) is designed to provide a warm humidified wound environment, and aims to minimize the effects of tissue cooling and reduce airborne particles from entering the surgical site. This study aims to evaluate the effectiveness of HumiGard to deflect airborne particles under a static wound and during a dynamic simulation of open spine surgery.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA cadaveric simulation of a lumbar laminectomy and L4-L5 posterolateral fusion surgery was performed under a conventional laminar downflow system. HumiGard was adhered to the surgical site prior to the incision and airborne particles (0.3 \u0026micro;m to 10 \u0026micro;m) were continuously measured at the wound using an Optical Particle Sizer. Static wound particle counts were assessed using a HumiGard ON/OFF cycling protocol to evaluate the device specific effects of HumiGard on wound particle counts. In addition, particle counts during the surgical procedure were measured. Particle counts under standard care (control) and HumiGard conditions (intervention) were compared using non-parametric statistical analysis.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eActivation of HumiGard produced immediate and pronounced reductions in particle counts under both static wound and procedural conditions. Median airborne particle counts were reduced by 96% compared to control conditions in a static wound (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Under dynamic open spine surgery, median airborne particle counts were reduced by 72% compared to control conditions (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001), excluding particle counts during diathermy use.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis study demonstrates active deflection of exogenous particles with HumiGard during a static wound and dynamic cadaveric model of open spine surgery. These findings suggest that HumiGard may be a valuable tool to minimize airborne wound contamination and infection risk during orthopedic surgery, in addition to current infection prevention protocols.\u003c/p\u003e","manuscriptTitle":"Surgical humidification (HumiGard™) reduces the number of airborne particles entering an open spine wound","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-15 17:49:57","doi":"10.21203/rs.3.rs-9708096/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"028cbc96-b952-48a4-a783-9a8a8ad8d735","owner":[],"postedDate":"May 15th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T17:49:57+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-15 17:49:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9708096","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9708096","identity":"rs-9708096","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}