Monoclonal antibody therapies for aquaporin-4-immunoglobulin G-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease.

Monoclonal antibody therapies mark the new era of targeted treatment for relapse prevention in aquaporin-4 (AQP4)-immunoglobulin G (IgG)-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD). For over a decade, rituximab, an anti-CD20 B-cell-depleting agent, had been the most effectiveness treatment for AQP4-IgG+NMOSD. Tocilizumab, an anti-interleukin-6 receptor, was also observed to be effective. In 2019, several randomized, placebo-controlled trials were completed that demonstrated the remarkable efficacy of eculizumab (anti-C5 complement inhibitor), inebilizumab (anti-CD19 B-cell-depleting agent), and satralizumab (anti-interleukin-6 receptor), leading to the Food and Drug Administration (FDA) approval of specific treatments for AQP4-IgG+NMOSD for the first time. Most recently, ravulizumab (anti-C5 complement inhibitor) was also shown to be highly efficacious in an open-label, external-controlled trial. Although only some patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) warrant immunotherapy, there is currently no FDA-approved treatment for relapse prevention in MOGAD. Observational studies showed that tocilizumab was associated with a decrease in relapses, whereas rituximab seemed to have less robust effectiveness in MOGAD compared to AQP4-IgG+NMOSD. Herein, we review the evidence on the efficacy and safety of each monoclonal antibody therapy used in AQP4-IgG+NMOSD and MOGAD, including special considerations in children and women of childbearing potential.

Effect of pilot-guided implant placement concept on the accuracy of osteotomy preparation and implant placement.

PURPOSE: To evaluate the accuracy of osteotomy preparation and implant placement for 3 pilot-guided (PG) concepts, namely, a surgical template with a metal sleeve (MS), a surgical template with an in-built nonmetal sleeve (NMS), and a surgical template with an in-built nonmetal sleeve for round bur indentation (RB). METHODS: Surgical models with missing maxillary molars were studied. The MS templates were designed to accept metal sleeves, while the NMS and RB templates were designed with in-built nonmetal sleeves. Ten templates were tested per group (n = 10). After each step (pilot drilling, 2nd drilling, 3rd drilling, profiling, and implant placement), the surgical model was scanned and compared against the planning model to determine maximum horizontal deviation (MHD) and maximum angle deviation (MAD). RESULTS: The MS and NMS templates exhibited a similar increase in MHD with successive drilling steps. The MAD for the pilot drilling step was significantly lower for MS than for the other groups. However, the differences among groups for MHD and MAD diminished in later steps. All templates had an MHD of 1.0 mm or less and an MAD less than 8°. CONCLUSION: The investigated PG implant placement concepts resulted in similar deviations in the placed implants.

A feasibility study on the efficacy of a patient-owned wound surveillance system for diabetic foot ulcer care (ePOWS study).

Objective: Wound image analysis tools hold promise in helping patients to monitor their wounds. We aim to perform a novel feasibility study on the efficacy of a patient-owned wound surveillance system for diabetic foot ulcer (DFU) care. Methods: This two-institutional, prospective, single-arm pilot study examined patients with DFU. An artificial intelligence-enabled image analysis app calculating the wound surface area was installed and patients or caregivers were instructed to take pictures of wounds during dressing changes. Patients were followed until wound deterioration, wound healing, or wound stability at 6 months occurred and the outcomes of interest included study adherence, algorithm performance, and user experience. Results: Between January 2021 and December 2021, 39 patients were enrolled in the study, with a mean age of 61.6 ± 8.6 years, and 69% (n = 27) of subjects were male. All patients had documented diabetes and 85% (n = 33) of them had peripheral arterial disease. A mean follow-up for those completing the study was 12.0 ± 8.5 weeks. At the conclusion of the study, 80% of patients (n = 20) had primary wound healing whilst 20% (n = 5) had wound deterioration. The study completion rate was 64% (n = 25). Usage of the app for surveillance of DFU healing, as compared to physician evaluation, yielded a sensitivity of 100%, specificity of 20%, positive predictive value of 83%, and negative predictive value of 100%. Of those who provided user experience feedback, 59% (n = 10) felt the app was easy to use, 47% (n = 8) would recommend the wound analysis app to others but only 6% would pay for the app out of pocket (n = 1). Conclusion: Implementation of a patient-owned wound surveillance system is feasible. Most patients were able to effectively monitor wounds using a smartphone app-based solution. The image analysis algorithm demonstrates strong performance in identifying wound healing and is capable of detecting deterioration prior to interval evaluation by a physician. Patients generally found the app easy to use but were reluctant to pay for the use of the solution out of pocket.

3D Capsule Networks for Brain Image Segmentation.

BACKGROUND AND PURPOSE: Current autosegmentation models such as UNets and nnUNets have limitations, including the inability to segment images that are not represented during training and lack of computational efficiency. 3D capsule networks have the potential to address these limitations. MATERIALS AND METHODS: We used 3430 brain MRIs, acquired in a multi-institutional study, to train and validate our models. We compared our capsule network with standard alternatives, UNets and nnUNets, on the basis of segmentation efficacy (Dice scores), segmentation performance when the image is not well-represented in the training data, performance when the training data are limited, and computational efficiency including required memory and computational speed. RESULTS: The capsule network segmented the third ventricle, thalamus, and hippocampus with Dice scores of 95%, 94%, and 92%, respectively, which were within 1% of the Dice scores of UNets and nnUNets. The capsule network significantly outperformed UNets in segmenting images that were not well-represented in the training data, with Dice scores 30% higher. The computational memory required for the capsule network is less than one-tenth of the memory required for UNets or nnUNets. The capsule network is also >25% faster to train compared with UNet and nnUNet. CONCLUSIONS: We developed and validated a capsule network that is effective in segmenting brain images, can segment images that are not well-represented in the training data, and is computationally efficient compared with alternatives.

A 10-year Australian experience of rare intraabdominal venous thrombosis with comparison to deep vein thrombosis and pulmonary embolism.

OBJECTIVE: Intra-abdominal venous thromboembolism is rare with heterogeneous management. We aim to evaluate these thrombosis and compare them to deep vein thrombosis and/or pulmonary embolism. METHOD: A 10-year retrospective evaluation of consecutive venous thromboembolism presentations (January 2011-December 2020) at Northern Health, Australia, was conducted. A subanalysis of intraabdominal venous thrombosis involving splanchnic, renal and ovarian veins was performed. RESULTS: There were 3343 episodes including 113 cases of intraabdominal venous thrombosis (3.4%) - 99 splanchnic vein thrombosis, 10 renal vein thrombosis and 4 ovarian vein thrombosis. Of the splanchnic vein thrombosis presentations, 34 patients (35 cases) had known cirrhosis. Patients with cirrhosis were numerically less likely to be anticoagulated compared to noncirrhotic patients (21/35 vs. 47/64, P  = 0.17). Noncirrhotic patients ( n  = 64) were more likely to have malignancy compared to those with deep vein thrombosis and/or pulmonary embolism (24/64 vs. 543/3230, P  < 0.001), including 10 patients diagnosed at time of splanchnic vein thrombosis presentation. Cirrhotic patients reported more recurrent thrombosis/clot progression (6/34) compared to noncirrhotic patients (3/64) (15.6 vs. 2.3 events/100-person-years; hazard ratio 4.7 (95% confidence interval 1.2-18.9), P  = 0.030) and other venous thromboembolism patients (2.6/100-person-years; hazard ratio 4.7, 95% confidence interval 2.1-10.7; P  < 0.001) with comparable major bleeding rates. All renal vein thrombosis were provoked including five malignant-related cases while three ovarian vein thrombosis occurred postpartum. No recurrent thrombotic or bleeding complications were reported in renal vein thrombosis and ovarian vein thrombosis. CONCLUSION: These rare intraabdominal venous thromboses are often provoked. Splanchnic vein thrombosis (SVT) patients with cirrhosis have a higher rate of thrombotic complications, while SVT without cirrhosis was associated with more malignancy. Given the concurrent comorbidities, careful assessment and individualized anticoagulation decision is needed.

Malignancies in Immunoglobulin G4-related ophthalmic disease.

PURPOSE: Clinical phenotypes in Immunoglobulin G4-related disease (IgG4-RD) according to the patterns of affecting organs have different risks of malignancies. We attempt to determine the association of malignancies with IgG4-related ophthalmic disease (IgG4-ROD). DESIGN: Retrospective cohort study. METHODS: Review of medical records, orbital images and histopathology reports in a territory-wide cohort of biopsy proven IgG4-ROD patients from 2005-2019. FINDINGS: Among 122 patients who had biopsies taken from adnexal lesions including lacrimal glands (n = 108), orbital mass (n = 30), infiltrated orbital fat (n = 10), conjunctiva (n = 2) or extraocular muscles (n = 3), 13% (16/122) developed malignancies over 73 ± 48months' follow-up. There were 9 cases of ocular adnexal lymphoma (OAL) and 7 extra-orbital malignancies. Compared with the general population, the incidence of OAL was significantly higher (standardized incidence ratios, SIRs = 10.0, 95%CI = 4.5-17.6) while that of extra-orbital malignancies was similar. The SIRs was highest within the first year (SIR = 46.7, 95%CI = 18.5-87.6) when 7 OAL were concomitantly diagnosed. Patients who developed OAL or extra-orbital malignancies were older than other patients at IgG4-ROD diagnosis (64.9 ± 7.1, 68.3 ± 8.5 versus 55.2 ± 15.0 years, P < 0.05). Asymmetric lacrimal gland enlargement (78% versus 13%), lack of frontal (0% versus 12%) or infraorbital nerve enlargement (0% versus 36%) were associated with OAL (all P < 0.05). Pre-treatment serum IgG4 level or extra-orbital IgG4-RD involvement was similar among patients with or without malignancies. CONCLUSION: In this biopsy-proven IgG4-ROD cohort, 7% developed OAL which was 10 times higher than the general population. Patients with asymmetric lacrimal gland enlargement or without trigeminal nerves involvement radiologically were associated with OAL.

Efficacy of Qingre Huashi decoction on infection of : inhibiting adhesion, antioxidant, and anti-inflammation.

OBJECTIVE: To investigate the phytochemical profile of Qingre Huashi decoction (, QHD) and evaluate the mechanisms rationalizing the use of QHD against ()-associated gastritis. METHODS: QHD is composed of 11 herbs, which was prepared by a fixed Pharmacy and concentrated into clear paste. High-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF/MS) was used to detect the phytochemical profile of QHD. The toxicity of QHD against and human gastric epithelial cells was evaluated by the toxicology test and cell counting kit-8 assay. The adhesion model was constructed by incubating and gastric mucosal epithelial cells for 2 h. The urease assay was used to examine the anti-adhesion effects of QHD, and gene expression of adhesins was evaluated by quantitative polymerase chain reaction. The antioxidant activity was assessed by DCFH-DA labeling. To evaluate the anti-inflammatory effect, the levels of pro-inflammatory cytokines in the culture supernatant were detected by enzyme-linked immunosorbent assay. RESULTS: HPLC-QTOF/MS profiling indicated the presence of primary compounds 1-20 in QHD. Drug concentration was determined as 1, 2, and 5 mg/mL by the toxic concentration of QHD against and human gastric epithelial cells. QHD prevented adhesion to the human gastric epithelial cells and reduced levels of reactive oxygen species. QHD also reduced the level of interleukin-8 and other pro-inflammatory cytokines that were upregulated by infection. CONCLUSION: QHD could inhibit adhesion, and exert antioxidant and anti-inflammatory effects .

[The relationship between insulin resistance and risk of long-term mortality in people without diabetes: a 30-year follow-up of the Daqing Diabetes Study].

Objective: To determine whether insulin resistance is associated with all-cause mortality in subjects without diabetes. Methods: A total of 505 participants without diabetes, 198 with normal glucose tolerance (NGT) and 307 with impaired glucose tolerance (IGT), were recruited from the Daqing Diabetes Study. The participants were followed up for 30 years. They were stratified into three groups (tertiles) according to baseline homeostasis model assessment of insulin resistance(HOMA-IR) levels, as the HOMA-IR 0, the HOMA-IR 1 and the HOMA-IR 2 groups, to assess the predictive effect of insulin resistance on risk of all-cause mortality. Results: During the 30-year follow-up, 52, 56 and 78 participants died across the three HOMA-IR groups, respectively. The corresponding mortality per 1 000 person-years (95%CI) were 12.12 (9.56-15.01), 13.10 (10.46-16.03) and 19.91 (16.73-23.15), respectively. Participants in the HOMA-IR 2 group had a significantly higher risk of death than those in the HOMA-IR 0 group after adjustment of age, sex and smoking status (HR=1.97,95%CI 1.38-2.81, P<0.001). Cox analyses showed that a one standard deviation increase in HOMA-IR was associated with a 22% increase in the mortality after adjustment of potential confounders (HR=1.22, 95%CI 1.08-1.39, P=0.002). Conclusions: Insulin resistance is associated with increased risk of all-cause death in Chinese people without diabetes, suggesting that improving insulin resistance could be beneficial for people without diabetic in reducing risk of long-term all-cause mortality.

Age, sex and racial differences in fibrin formation and fibrinolysis within the healthy population.

Increased fibrin generation and reduced fibrinolytic potential have been detected using global coagulation assays in several hypercoagulable states including cardiovascular disease and venous thromboembolism. We aimed in this study to define the impact of age, sex and race on fibrin generation and lysis using the Overall Haemostatic Potential (OHP) assay in a group of stringently defined healthy adults. Healthy adult patients not receiving anticoagulation and without a history of thrombotic disease were prospectively recruited. Iindividuals with cardiovascular risk factors (e.g. hypertension, diabetes, smoking), receiving hormonal therapy, antiplatelet agents or with abnormal routine blood tests were also excluded. Platelet-poor plasma was obtained and the OHP assay, which evaluates fibrin formation with and without tissue plasminogen activator, was performed on all plasma samples. 144 healthy subjects (34.7% male) with median age 42 years (interquartile range 20, 77) were recruited. After multivariate analysis, age at least 50 years and female sex were associated with significantly increased fibrin generation parameters (overall coagulation potential, OHP, maximum optical density, fibrin) as well as reduced markers of fibrinolysis (overall fibrinolytic potential and time-to-50% lysis). There were no significant differences in OHP parameters between whites, East Asians and South Asians after accounting for age and sex. This study defines age, sex and racial differences of fibrin generation and fibrinolysis as measured by the OHP assay in a sample of healthy subjects. Further studies are warranted in diseased populations, where there is growing awareness of the role of global coagulation assay in defining prothrombotic and hypofibrinolytic states.

SARS-CoV-2 N Protein Induces Acute Kidney Injury via Smad3-Dependent G1 Cell Cycle Arrest Mechanism.

COVID-19 is infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and can cause severe multiple organ injury and death. Kidney is one of major target organs of COVID-19 and acute kidney injury (AKI) is common in critically ill COVID-19 patients. However, mechanisms through which COVID-19 causes AKI remain largely unknown and treatment remains unspecific and ineffective. Here, the authors report that normal kidney-specifically overexpressing SARS-CoV-2 N develops AKI, which worsens in mice under ischemic condition. Mechanistically, it is uncovered that SARS-CoV-2 N-induced AKI is Smad3-dependent as SARS-CoV-2 N protein can interact with Smad3 and enhance TGF-ß/Smad3 signaling to cause tubular epithelial cell death and AKI via the G1 cell cycle arrest mechanism. This is further confirmed in Smad3 knockout mice and cells in which deletion of Smad3 protects against SARS-CoV-2 N protein-induced cell death and AKI in vivo and in vitro. Most significantly, it is also found that targeting Smad3 with a Smad3 pharmacological inhibitor is able to inhibit SARS-CoV-2 N-induced AKI. In conclusion, the authors identify that SARS-CoV-2 N protein is a key mediator for AKI and induces AKI via the Smad3-dependent G1 cell cycle arrest mechanism. Targeting Smad3 may represent as a novel therapy for COVID-19-asscoaited AKI.

Seroprevalence of Pteropine orthoreovirus in humans remain similar after nearly two decades (2001-2002 vs. 2017) in Tioman Island, Malaysia.

Pteropine orthoreovirus (PRV) is an emerging zoonotic respiratory virus that can be transmitted from bats to humans. In Malaysia, aside from PRV2P (Pulau virus) being isolated from Pteropus hypomelanus sampled in Tioman Island, PRV3M (Melaka virus), PRV4K (Kampar virus), and PRV7S (Sikamat virus) were all isolated from samples of patients who reported having a disease spectrum from acute respiratory distress to influenza-like illness and sometimes even with enteric symptoms such as diarrhea and abdominal pain. Screening of sera collected from human volunteers on Tioman Island in 2001-2002 demonstrated that 12.8% (14/109) were positive for PRV2P and PRV3M. Taking all these together, we aim to investigate the serological prevalence of PRV (including PRV4K and PRV7S) among Tioman Island inhabitants again with the assumption that the seroprevalence rate will remain nearly similar to the above reported if human exposure to bats is still happening in the island. Using sera collected from human volunteers on the same island in 2017, we demonstrated seroprevalence of 17.8% (28/157) against PRV2P and PRV3M, respectively. Seropositivity of 11.4% among Tioman Island inhabitants against PRV4K and PRV7S, respectively, was described in this study. In addition, the seroprevalence of 89.5% (17/19), 73.6% (14/19), 63.0% (12/19), and 73.6% (14/19) against PRV2P, PRV3M, PRV4K, and PRV7S, respectively, were observed among pteropid bats in the island. We revealed that the seroprevalence of PRV among island inhabitants remains nearly similar after nearly two decades, suggesting that potential spill-over events in bat-human interface areas in the Tioman Island. We are unclear whether such spillover was directly from bats to humans, as suspected for the PRV3M human cases, or from an intermediate host(s) yet to be identified. There is a high possibility of the viruses circulating among the bats as demonstrated by high seroprevalence against PRV in the bats.

[Value of heart rate-blood pressure product of multiplication for identifying compensated shock in children].

Objective: To estimate the predictive value of heart rate (HR)-blood pressure (BP) products of multiplication for compensated shock in children. Methods: The study population consisted of 99 children with shock who had lactate measured before receiving vasopressor agents in Department of Critical Care Medicine of Children's Hospital, Capital Institute of Pediatrics from October 2015 to March 2021. The clinical data including the HR, BP, HR to BP ratio, HR-BP product and lactate at admission and after the correction of shock, as well as the 28-day mortality were collected. According to the outcome at the 28th day, the patients were divided into survival group and non-survival group. Comparisons between groups were performed with unpaired Student t test, or Mann-Whitney U test, or chi-square test. Pearson correlation analysis was used to analyze the correlations between lactate and HR, BP, HR to BP ratio and HR-BP product, respectively. Receiver operating characteristic (ROC) curve was analyzed to evaluate the predictive values of HR, BP, HR to BP ratio and HR-BP product for lactate greater than 2 mmol/L. Results: In these 99 children, 49 were males, and the median age was 3.8 (0.7-6.0) years. The most common type of shock was septic shock (61 cases, 62%), followed by cardiogenic shock (12 cases, 12%), hemorrhagic shock (12 cases, 12%), Kawasaki disease shock syndrome (8 cases, 8%) and anaphylactic shock (6 cases, 6%). Sixty-six patients (67%) survived, and 33 patients (33%) died. ROC curve showed that the area under curves (AUC) of lactate (optimal cutoff value 3.15 mmol/L, sensitivity 96.0%, specificity 54.4%, P<0.01) and HR to systolic blood pressure ratio (HR/SBP) (optimal cutoff value 2.0 times/(min·mmHg), sensitivity 62.5%, specificity 69.0%, P = 0.03) for predicting adverse outcome were 0.769 and 0.649, respectively. There were significant correlations between lactate and HR to diastolic blood pressure (DBP) ratio, HR to mean blood pressure (MBP) ratio, SBP, HR/SBP, MBP, DBP and HR (r= 0.476, 0.452, -0.444, 0.425,-0.410, -0.364, 0.177, all P<0.01), while no significant correlation was found between lactate and the products of HR and BP(all P>0.05). HR/SBP performed better than the other six parameters for predicting lactate>2 mmol/L, with the AUC of 0.872 and the optimal cutoff value of 1.4 bpm/mmHg (sensitivity 92.1%, specificity 70.9%, P<0.01). When MBP was greater than or equal to 65 mmHg, MBP × HR, DBP × HR, SBP × HR, HR, HR/SBP, HR/MBP and HR/DBP were significantly correlated with lactate (r= 0.706, 0.705, 0.669, 0.626, 0.555, 0.502, 0.446, all P<0.01). And MBP × HR performed better for predicting lactate>2 mmol/L than the other six parameters, with the AUC of 0.974 and the optimal cutoff value of 9446 bpm × mmHg (sensitivity 100.0%, specificity 90.9%, P<0.01). Conclusions: The product of HR and BP, especially the MBP × HR, shows higher predictive values for abnormally elevated lactate in children with compensated shock than the HR/SBP does. It is worth recommending for early identification of compensated shock in children.

Quantifying the rate of recurrence of postoperative Crohn's disease with biological therapy. A meta-analysis.

OBJECTIVE: Preventing the postoperative recurrence (POR) of Crohn's disease (CD) poses a significant challenge to clinicians. With the advent of biologics, various studies have observed a reduction of recurrence after surgery. Hence, we performed a systematic review and meta-analysis to identify the rate of POR at different time points in the era of biologic use. METHODS: We performed a literature search using Medline and Embase databases for studies investigating biologics in preventing the POR of CD. Data were extracted, and a single-arm meta-analysis with generalized linear mixed model and Clopper-Pearson method for confidence interval (CI) was performed to identify endoscopic, clinical and surgical recurrence rates at 6 months and 1, 2 and 5 years postoperatively. RESULTS: Altogether 24 studies were included in the meta-analysis. The endoscopic, clinical and surgical POR rate with the use of anti-tumor necrosis factor (TNF)-α agents at 1 year was 21.72% (95% CI 16.28%-28.37%), 13.06% (95% CI 8.18%-18.92%) and 3.76% (95% CI 1.37%-9.91%), respectively. The 5-year recurrence rate was 84.21% (95% CI 72.35%-91.57%) and 17.49% (95% CI 9.17%-30.80%) for endoscopic and surgical recurrence, respectively. Subgroup analyses at 1 year for the type of anti-TNF-α agent or the timing of initiation after surgery showed no significant difference in endoscopic, clinical and surgical recurrence rates. CONCLUSIONS: Anti-TNF-α agents are effective at preventing clinical, endoscopic and surgical POR of CD. The timing of initiating biological therapy after surgery has no significant effect on the rate of POR. The efficacy of infliximab and adalimumab for postoperative recurrence prevention is similar.

Efficacy of laparoscopic gastric bypass vs laparoscopic sleeve gastrectomy in treating obesity combined with type-2 diabetes.

OBJECTIVE: This prospective study compared the efficacy and safety of laparoscopic gastric bypass and laparoscopic sleeve gastrectomy in treating overweight and obese patients with BMI>28 kg/m2 and type-2 diabetes. METHODS: Patients were randomized into a gastric bypass group (n = 77) or a gastrectomy group (n = 80). The surgery time, intraoperative blood loss, recovery time, and hospitalization time were collected. BMI, waistline, hipline, C-peptide level, insulin resistance index (HOMA-IR), and their blood and lipid profile were also measured. RESULTS: Surgery time and blood loss were significantly higher in the gastrectomy group, when compared to the gastric bypass group (P < 0.05). In both groups, the levels of BMI, waist circumference and hip circumference (but not their ratio) gradually and significantly decreased after surgery compared with baseline (P < 0.05), and no significant difference was found between these two groups. The C-peptide level, HOMA-IR, fasting blood glucose, 2-hour postprandial blood glucose and glycosylated haemoglobin gradually and significantly decreased after surgery compared with the values before treatment (P < 0.05). The levels of total cholesterol, triglyceride, LDL, and monocyte chemoattractant protein-1 were also lower after surgery in both groups, while HDL and glucagon-like peptide-1 were significantly higher after surgery compared with the values before treatment (P < 0.05). However, no significant difference was found between these two groups of patients. CONCLUSION: Both laparoscopic gastric bypass and laparoscopic sleeve gastrectomy improved the BMI and diabetic conditions of overweight/obese diabetics, while laparoscopic sleeve gastrectomy had a shorter surgical time and less blood loss.

[Application of mixed reality technique for the surgery of oral and maxillofacial tumors].

OBJECTIVE: To explore the application of mixed reality technique for the surgery of oral and maxillofacial tumors. METHODS: In this study, patients with a diagnosis of an oral and maxillofacial tumor who were referred to Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from December 2018 to January 2020 were selected. The preoperative contrast-enhanced computed tomography data of the patients were imported into StarAtlas Holographic Medical Imaging System (Visual 3D Corp., Beijing, China). Three-dimensional (3D) model of tumor and key structures, such as skeleton and vessels were reconstructed to three-dimensionally present the spatial relationship between them, followed with the key structures delineation and preoperative virtual surgical planning. By using mixed reality technique, the real-time 3D model was displayed stereotactically in the surgical site. While keeping sterile during operation, the surgeon could use simple gestures to adjust the 3D model, and observed the location, range, and size of tumor and the key structures adjacent to the tumor. Mixed reality technique was used to assist the operation: 3D model registration was performed for guidance before tumor excision; intraoperative real-time verification was performed during tumor exposure and after excision of the tumor. The Likert scale was used to evaluate the application of mixed reality technique after the operation. RESULTS: Eight patients underwent mixed reality assisted tumor resection, and all of them successfully completed the operation. The average time of the 3D model registration was 12.0 minutes. In all the cases, the surgeon could intuitively and three-dimensionally observe the 3D model of the tumor and the surrounding anatomical structures, and could adjust the model during the operation. The results of the Likert scale showed that mixed reality technique got high scores in terms of perceptual accuracy, helping to locate the anatomical parts, the role of model guidance during surgery, and the potential for improving surgical safety (4.22, 4.19, 4.16, and 4.28 points respectively). Eight patients healed well without perioperative complications. CONCLUSION: By providing real-time stereotactic visualization of anatomy of surgical site and guiding the operation process through 3D model, mixed reality technique could improve the accuracy and safety of the excision of oral and maxillofacial tumors.