A magnetic massive star has experienced a stellar merger.

Massive stars (those ≥8 solar masses at formation) have radiative envelopes that cannot sustain a dynamo, the mechanism that produces magnetic fields in lower-mass stars. Despite this, approximately 7% of massive stars have observed magnetic fields, the origin of which is debated. We used multi-epoch interferometric and spectroscopic observations to characterize HD 148937, a binary system of two massive stars. We found that only one star is magnetic and that it appears younger than its companion. The system properties and a surrounding bipolar nebula can be reproduced with a model in which two stars merged (in a previous triple system) to produce the magnetic massive star. Our results provide observational evidence that magnetic fields form in at least some massive stars through stellar mergers.

Swallowing Function After Treatment of Laryngeal Cancer.

Dysphagia is a common functional outcome following treatment of laryngeal cancer. Despite curative advances in both nonsurgical and surgical approaches, preserving and optimizing swallowing function is critical. Understanding the nature and severity of dysphagia depending on initial tumor staging and treatment modality and intensity is crucial. This chapter explores current evidence on the acute and chronic impacts of treatments for laryngeal cancer on swallow function, as well as the medical and nonmedical management of dysphagia in this population.

Retrograde Cricopharyngeus Dysfunction: The Jefferson Experience.

OBJECTIVES: To describe our center's experience with the identification and treatment of retrograde cricopharyngeus dysfunction (R-CPD), a syndrome involving the inability to belch previously described by only one institution. Additionally, because all patients initially learned of their condition and sought treatment as a result of social media posts, we queried their source and comfort with this form of medical referral. METHODS: Retrospective chart review of patients who underwent botulism toxin injection into the cricopharyngeus muscle for treatment of R-CPD from 2019 to 2022. Demographic data, most common symptoms at presentation, and response to treatment and complications were documented. Post-treatment questionnaires were reviewed. RESULTS: A total of 85 patients were identified. Mean age at surgery was 27 years. There were 54 (63.5%) females and 31 (36.5%) males. The inability to burp (98.8%), bloating (92.9%), gurgling noises (31.8%), and excessive flatulence (21.2%) were the most common symptoms. The minimum units of botox utilized were 25, whereas the maximum was 100. The majority of patients (88.2%) had a successful response at initial follow-up visit. The most common complication was mild dysphagia (30.6%), which was transient for all patients. Most patients learned of our practice through social media, with only one patient being referred by a medical provider. CONCLUSIONS: The majority of patients in our cohort were young and female. The inability to burp and bloating were the most common presenting symptoms. Social media was the primary source of referral. Our institution favors 80-100 units for an effective response. Laryngoscope, 133:1081-1085, 2023.

(Sub)stellar companions shape the winds of evolved stars.

Binary interactions dominate the evolution of massive stars, but their role is less clear for low- and intermediate-mass stars. The evolution of a spherical wind from an asymptotic giant branch (AGB) star into a nonspherical planetary nebula (PN) could be due to binary interactions. We observed a sample of AGB stars with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that their winds exhibit distinct nonspherical geometries with morphological similarities to planetary nebulae (PNe). We infer that the same physics shapes both AGB winds and PNe; additionally, the morphology and AGB mass-loss rate are correlated. These characteristics can be explained by binary interaction. We propose an evolutionary scenario for AGB morphologies that is consistent with observed phenomena in AGB stars and PNe.

Anemia and blood transfusion requirements in endoscopic sinus surgery: A propensity-matched analysis.

OBJECTIVE: Massive bleeding requiring blood transfusion is a feared complication of endoscopic sinus surgery (ESS). In an effort to improve healthcare quality and outcomes, research is focused on identifying the risk factors for complications following surgical procedures. Blood transfusions have been linked to increased complication rates, but their role has not been extensively studied in ESS. METHODS: The American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) participant user files 2005 to 2014 were queried for all cases of ESS. Patients were divided into cohorts based on anemia (hematocrit <39.00 in men and <36.00 in women) and hematocrit levels. Univariate analyses and a propensity score-matching algorithm were employed. RESULTS: Of 630 cases of ESS, 117 (18.6%) had preexisting anemia. Anemic patients were more likely to be black (19.8% vs. 6.7%, P ≤ 0.001), undergo longer operation times (117.50 minutes ±155.73 vs. 129.85 minutes ±36.03, P = 0.005), have diabetes (28.2% vs. 10.9%, P ≤ 0.001), and have hypertension (46.2% vs. 33.1%, P = 0.010). Following propensity score matching, 109 cases were selected for each cohort, with no significant differences in demographics, comorbidities, operation time, or outpatient status. The anemic cohort was independently associated with an increase in overall postoperative complications (17.4% vs. 7.3%, P = 0.038). Transfusion use was significantly associated with preoperative hematocrit levels <30 (30.0% vs. 4.5%, P = 0.001) and between 30 and 34.99 (13.9% vs. 2.5%, P = 0.011). CONCLUSION: Preoperative anemia is a significant predictor of overall complications and bleeding requiring transfusion for patients undergoing ESS. These results highlight the need for careful preoperative assessment and management of anemia in this population. LEVEL OF EVIDENCE: NA Laryngoscope, 130:1377-1382, 2020.

Morbidity and mortality associated with ventral skull base surgery: analysis of the National Surgical Quality Improvement Program.

BACKGROUND: Ventral skull base (VSB) surgery has associated morbidity and mortality that is poorly defined. In this study we aim to identify factors associated with adverse events in VSB surgery. METHODS: We queried the database of the American College of Surgeons National Surgical Quality Improvement Program for cases of VSB surgery during the period 2005-2014. Patients with complications, readmissions, reoperations, or mortality were compared to those without adverse events. RESULTS: Nine hundred patients were included; 253 (28.1%) had complications, underwent reoperation, were readmitted, or died. These patients were older (42.6% vs 32.8, p = 0.032) and had higher rates of congestive heart failure (CHF) (3.2% vs 0.2%, p < 0.0001), disseminated cancer (8.3% vs 4.6%, p = 0.032), and preoperative sepsis (8.7% vs 2.2%, p < 0.0001). Other comorbidities included long-term steroid use (13.4% vs 9.0%, p = 0.046) and higher rates of preoperative transfusion (2.4% vs 0%, p < 0.0001). The most common complication was bleeding (13.7%). Preoperative systemic sepsis (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.0-6.6) and lower hematocrit (OR, 2.1; 95% CI, 1.4-3.4) were more likely to be associated with a complication. Those with disseminated cancer (OR, 12.0; 95% CI, 2.9-50.5) were more likely to experience 30-day mortality. Black patients had lower rates of reoperation (OR, 0.3; 95% CI, 0.1-0.8), whereas patients with CHF (OR, 12.6; 95% CI, 1.7-94.4) and hypertension (OR, 2.1; 95% CI, 1.1-4.0) had higher rates of reoperation. Predictors of extended length of stay were Hispanic ethnicity (OR, 2.2; 95% CI, 1.2-4.1) and lower hematocrit (OR, 2.3; 95% CI, 1.5-3.6). CONCLUSION: VSB surgery can involve significant morbidity and mortality, and thus identifying risk factors allows for better prognostication and delivery of care in these patients.

Prediction and Staging of Hepatic Fibrosis in Children with Hepatitis C Virus: A Machine Learning Approach.

OBJECTIVES: The aim of this study is to develop an intelligent diagnostic system utilizing machine learning for data cleansing, then build an intelligent model and obtain new cutoff values for APRI (aspartate aminotransferase-to-platelet ratio) and FIB-4 (fibrosis score) for the prediction and staging of fibrosis in children with chronic hepatitis C (CHC). METHODS: Random forest (RF) was utilized in this study for data cleansing; then, prediction and staging of fibrosis, APRI and FIB-4 scores and their areas under the ROC curve (AUC) have been obtained on the cleaned dataset. A cohort of 166 Egyptian children with CHC was studied. RESULTS: RF, APRI, and FIB-4 achieved high AUCs; where APRI had AUCs of 0.78, 0.816, and 0.77; FIB-4 had AUCs of 0.74, 0.828, and 0.78; and RF had AUCs of 0.903, 0.894, and 0.822, for the prediction of any type of fibrosis, advanced fibrosis, and differentiating between mild and advanced fibrosis, respectively. CONCLUSIONS: Machine learning is a valuable addition to non-invasive methods of liver fibrosis prediction and staging in pediatrics. Furthermore, the obtained cutoff values for APRI and FIB-4 showed good performance and are consistent with some previously obtained cutoff values. There was some agreement between the predictions of RF, APRI and FIB-4 for the prediction and staging of fibrosis.

Are video-urodynamics superior to traditional urodynamic studies in changing treatment decision with urinary symptoms?

Objective: To investigate the utility of video-urodynamic studies (VUDS) in patients with various urinary conditions and to evaluate if the addition of fluoroscopic imaging changes the treatment plans one would pursue if urodynamic studies (UDS) alone were performed as VUDS increases cost, radiation exposure, and patient discomfort. Patients and Methods: A retrospective chart review was conducted on all women who underwent VUDS from 2013 to 2015 at one institution. We hypothesised that the addition of the fluoroscopic images would not change the treatment plan. The protocol was conducted in two parts: (i) analysis of the patients' demographics, history, presentation, and VUDS results; then (ii) comparison of the documented VUDS diagnosis and plan with the theoretical diagnosis and plan of UDS alone. Results: Charts from 156 women were analysed. Fluoroscopic findings impacted the treatment plan in 60 patients. In 38 patients, fluoroscopic findings changed or added to the diagnosis. Vesico-ureteric reflux (VUR) was detected in 16 patients, nine were incidental findings (P < 0.001) in which there were no UDS findings of urinary retention (P = 0.01) or poor compliance (P = 0.02). Fluoroscopic findings of VUR significantly changed diagnosis (P < 0.001), but did not significantly change the treatment plan (P = 0.09). Conclusion: We conclude that fluoroscopic findings from VUDS do not add to or change the treatment plan. If there is a clinical concern for VUR, UDS with renal imaging would be able to detect findings or potential damage to the upper urinary tract without needing VUDS. Abbreviations: DESD: detrusor-external sphincter dyssynergia; LUT: lower urinary tract; POP: pelvic organ prolapse; PVR: post-void residual urine volume; SUFU: society of urodynamics, female pelvic medicine and urogenital reconstruction; (V)UDS: (video-) urodynamic study; UI: urinary incontinence.

Clinicopathologic traits and prognostic factors associated with pediatric sinonasal rhabdomyosarcoma.

BACKGROUND: Pediatric sinonasal rhabdomyosarcoma (RMS) is an aggressive and rare malignancy. This is the first multi-institutional study on the prognostic factors associated with outcomes in this population. METHODS: The National Cancer Database was queried for the period from 2004 to 2013 for all cases of malignant sinonasal RMS in the pediatric population. The impact of patients' demographics, tumor characteristics, and Intergroup Rhabdomyosarcoma Study Group (IRSG) staging on survival was assessed using chi-square test, Fisher's exact test, Kaplan-Meier test, and Cox regression analyses. RESULTS: A total of 157 cases of pediatric sinonasal RMS were identified. Mean age at diagnosis was 9.38 years and male patients comprised 48.4% of the cohort. The nasal cavity (31.8%) and maxillary sinus (30.6%) were the most common primary sites. Alveolar was the most common histology (49.7%), followed by embryonal type (32.5%). The majority of patients received solely chemoradiation (52.9%), followed by surgery with adjuvant chemoradiation (30.6%). Five-year overall survival (OS) was 55.2% (±4.5%). Metastatic disease was associated with a poorer 5-year OS rate (24.4% vs 61.5%; p = 0.010). Maxillary sinus site was associated with an improved survival (71.8% vs 47.6%; p = 0.009). On multivariate analysis, chemoradiation with or without surgery was an additional prognostic factor. Although IRSG clinical stages did not correlate with survival, high-risk patients in the IRSG clinical risk groups were associated with poorer survival on multivariate analysis (hazard ratio [HR], 2.005; 95% confidence interval, 1.007-3.993; p = 0.048). CONCLUSION: To date, this is the largest study on pediatric sinonasal RMS. IRSG clinical risk groups may be useful in stratifying high-risk patients with poor prognosis.

The Otolaryngology Match: A Bibliometric Analysis of 222 First-Year Residents.

OBJECTIVE/HYPOTHESIS: Research has long been acknowledged as important to successfully matriculate into an otolaryngology residency position. The objective of this study is to perform a bibliometric analysis to quantify the importance of scholarly productivity in the otolaryngology match process. STUDY DESIGN: Retrospective database review. METHODS: A list of all Accreditation Council for Graduate Medical Education-accredited otolaryngology residency programs were identified. Websites of programs were reviewed to identify first-year otolaryngology residents for the 2016 to 2017 academic year and compared to two previous academic years. Research output measures were collected. Residencies were tiered 1 to 5 by departmental research output. RESULTS: Two hundred twenty-two records of first-year otolaryngology residents starting residency in 2016 were identified. After adjusting for number of total publications, number of original research articles, number of review articles, number of case reports, number of first author publications, number of otolaryngology-related publications, highest journal impact factor, average journal impact factor, and years since publication, h-index and number of total publications were associated with increasing tier of matriculation based on research output (P < .0001). Only number of publications correlated with increasing h-index (B = 1.11). With regard to applicant trends, there has been an increase in scholarly productivity as measured across all research parameters in the past 3 years. CONCLUSIONS: Research is an important component of successfully matriculating into an otolaryngology residency program. The h-index is a reliable tool to quantify research output and predict the tier of matriculation with regard to institutional research output. There has been a steadily increasing level of scholarly output among applicants in the past 3 years. LEVEL OF EVIDENCE: NA Laryngoscope, 129:1561-1566, 2019.

Outpatient versus inpatient parotidectomy: Comparison of postoperative complication rates.

OBJECTIVES: Parotidectomies have become a common outpatient procedure, but their impact on postoperative complications as compared to inpatient procedures has not been evaluated in a multi-institutional study. STUDY DESIGN: The aim of this retrospective analysis was to evaluate the differences in outcomes using a standardized cohort of patients undergoing outpatient or inpatient parotidectomies. METHODS: The National Surgical Quality Improvement Program database was queried for parotidectomies between 2005 and 2014. Univariate analyses were conducted to compare the outpatient and inpatient cohorts. A propensity-matching algorithm was used to ensure equal distribution of demographics and preoperative comorbidities. RESULTS: Among the 4,368 parotidectomies examined, 2,915 (66.7%) were outpatient and 1,453 (33.3%) were inpatient. In the unmatched analysis, the inpatient group had higher rates of smokers (P = < 0.001), hypertension (P = 0.003), and disseminated cancer (P = 0.014). The outpatient group had higher rates of patients under age 40 years (P = 0.015), females (P = 0.016), and American Society of Anesthesiology class 1 and 2 (P = < 0.001). The total work relative value units (RVUs) were 17.01 ± 3.44 for the inpatient cohort and 16.19 ± 3.70 for the outpatient cohort (P = < 0.001). Following propensity matching, 1,352 cases were selected for each cohort, with no significant differences in comorbidities. Total work RVU after matching was 16.90 ± 3.47 for the inpatient group and 16.75 ± 3.44 for the outpatient group (P = .235). The matched inpatient cohort had increased rates of surgical complications (3.1% vs. 1.8%, P = 0.033), pneumonia (0.5% vs. 0.0%, P = 0.016), and overall complications (4.5% vs. 2.6%, P = 0.009). CONCLUSION: Outpatient parotidectomies are associated with similar as well as decreased complication rates as compared to inpatient parotidectomies. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:655-661, 2019.

Prediction and Staging of Hepatic Fibrosis in Children with Hepatitis C Virus: A Machine Learning Approach / 대한의료정보학회지

OBJECTIVES: The aim of this study is to develop an intelligent diagnostic system utilizing machine learning for data cleansing, then build an intelligent model and obtain new cutoff values for APRI (aspartate aminotransferase-to-platelet ratio) and FIB-4 (fibrosis score) for the prediction and staging of fibrosis in children with chronic hepatitis C (CHC). METHODS: Random forest (RF) was utilized in this study for data cleansing; then, prediction and staging of fibrosis, APRI and FIB-4 scores and their areas under the ROC curve (AUC) have been obtained on the cleaned dataset. A cohort of 166 Egyptian children with CHC was studied. RESULTS: RF, APRI, and FIB-4 achieved high AUCs; where APRI had AUCs of 0.78, 0.816, and 0.77; FIB-4 had AUCs of 0.74, 0.828, and 0.78; and RF had AUCs of 0.903, 0.894, and 0.822, for the prediction of any type of fibrosis, advanced fibrosis, and differentiating between mild and advanced fibrosis, respectively. CONCLUSIONS: Machine learning is a valuable addition to non-invasive methods of liver fibrosis prediction and staging in pediatrics. Furthermore, the obtained cutoff values for APRI and FIB-4 showed good performance and are consistent with some previously obtained cutoff values. There was some agreement between the predictions of RF, APRI and FIB-4 for the prediction and staging of fibrosis.

Understanding Risk Factors Associated With Unplanned Reoperation in Major Head and Neck Surgery.

Importance: Understanding the preoperative, intraoperative, and postoperative risk factors of reoperation is the optimal way to approach decreasing its incidence. Objective: To identify risk factors of unplanned reoperation following major operations of the head and neck. Design, Setting, and Participants: This retrospective cohort study queried the American College of Surgeons National Surgical Quality Improvement Program database and identified 2475 cases of major operations of the head and neck performed between 2005 and 2014. Specific operations analyzed were glossectomy, mandibulectomy, laryngectomy, and pharyngectomy. Univariate and multivariate analyses were performed to compare demographic and clinical characteristics of patients with or without unplanned reoperation. Data were analyzed between September and November 2017. Main Outcomes and Measures: The primary outcome was incidence of unplanned reoperation in patients with major operations in the head and neck region. An additional aim was to assess the risk factors associated with an increased likelihood of reoperation. Results: In total, 1941 patients were included in this study (1298 [66.9%] males), with most patients (961 [49.5%]) between 61 and 80 years of age. The overall unplanned reoperation rate within 30 days after the principal operative procedure was 14.2% (275 patients). The operative procedure with the highest reoperation rate was pharyngectomy (8 of 46 [17.4%]), followed by glossectomy (95 of 632 [15.0%]), laryngectomy (53 of 399 [13.3%]), and mandibulectomy (25 of 240 [10.4%]). Among the unplanned reoperation patients, 516 patients (76.8%) underwent reoperation during their initial hospital admission and 156 patients (23.2%) after readmission. The mean (SD) number of days from the principal operative procedure to unplanned reoperation was 8.5 (3.6) days for initial-admission reoperations and 16.0 (4.8) days for readmission reoperations. The most common unplanned reoperation procedures overall included repair, surgical exploration, and revision procedures on arteries and veins (47 of 2475 [1.9%]), incision procedures on the soft tissue of the neck and thorax (37 of 1941 [1.9%]), and incision and drainage procedures on the skin, subcutaneous, and accessory structures (21 of 1941 [1.1%]). Multivariate analysis results indicated that the independent risk factors for unplanned reoperation following a major cancer operation of the head or neck included black race (odds ratio [OR], 1.72; 95% CI, 1.09-2.74), disseminated cancer (OR, 1.85; 95% CI, 1.14-3.00), greater total operation time (OR, 2.05; 95% CI, 1.49-2.82), superficial (OR, 2.56; 95% CI, 1.55-4.24) or deep (OR, 4.83; 95% CI, 2.60-8.95) surgical site infection, wound dehiscence (OR, 8.36; 95% CI, 5.10-13.69), and ventilator dependence up to 48 hours after surgery (OR, 2.95; 95% CI, 1.79-4.87). Conclusions and Relevance: The identification of a significant association of black race, disseminated cancer, total operation time, surgical site infection in either the superficial or deep spaces, wound dehiscence, or ventilator dependence for more than 48 hours after surgery with increased risk of reoperation in major head and neck surgery may guide the modification and adaptation of these risk factors to decrease the burden that unplanned reoperation places on patients, surgeons, and the health care system.

Analysis of Risk Factors for Unplanned Reoperation Following Free Flap Surgery of the Head and Neck.

OBJECTIVES/HYPOTHESIS: Evaluate risk factors for unplanned reoperation following free flap surgery of the head and neck. STUDY DESIGN: Retrospective database review. METHODS: The National Surgical Quality Improvement Program database was queried for free flap surgeries of the head and neck between 2010 and 2014. Bivariate and multivariate analyses were performed to compare perioperative variables and postoperative complications in patients with and without unplanned reoperation. RESULTS: A total of 1,796 patients were identified, with an overall unplanned reoperation rate of 20.0% (n = 359) within 30 days after surgery. Upon multivariate analysis, independent preoperative risk factors for unplanned reoperation include smoking (odds ratio [OR]: 1.389, 95% confidence interval [CI]: 1.042-1.850), hypertension (OR: 1.443, 95% CI: 1.096-1.901), and prior open wound/wound infection (OR: 1.675, 95% CI: 1.123-2.499). Intraoperative risk factors include prolonged operative time (OR: 1.045, 95% CI: 1.021-1.070). Surgical site infection (OR: 6.518, 95% CI: 2.728-15.574), wound disruption (OR: 17.034, 95% CI: 8.373-34.654), blood transfusion (OR: 1.561, 95% CI: 1.062-2.296), and ventilation > 48 hours (OR: 3.626, 95% CI: 1.955-6.723) were significant postoperative predictors of unplanned reoperation. CONCLUSIONS: In patients with free flap surgeries of the head and neck, preoperative smoking, hypertension, and prior open wound/wound infection, along with prolonged operative time, are risk factors for 30-day unplanned reoperation. In addition, postoperative surgical site infection, wound disruption, blood transfusion, and ventilation >48 hours are independently associated with unplanned reoperation. LEVEL OF EVIDENCE: 4 Laryngoscope, 128:2790-2795, 2018.

State performance in pluripotent and adult stem cell research, 2009-2016.

AIM: To examine how the geographic distribution of pluripotent and adult stem cell research publications within the USA differs from other areas of biomedical research. MATERIALS & METHODS: Publication count data for pluripotent stem cell research, adult stem cell research and a comparison group representative of biomedical research more broadly were collected and analyzed for each US state from 2009 to 2016. RESULTS: The distribution of pluripotent stem cell research differed from the other fields with overperformance in pluripotent stem cell research observed in California, as well as Wisconsin, Massachusetts, Maryland and Connecticut. CONCLUSION: Our analysis suggests that permissive state stem cell policy may be one of the several factors contributing to strong state performance in pluripotent stem cell research.

An excess of massive stars in the local 30 Doradus starburst.

The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses ([Formula: see text]). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 [Formula: see text] and contains 32 ± 12% more stars above 30 [Formula: see text] than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 [Formula: see text], the IMF power-law exponent is [Formula: see text], shallower than the Salpeter value of 2.35.

Breast cancer awareness and breast self-examination in Northern Saudi Arabia. A preliminary survey.

OBJECTIVE: To elicit knowledge of breast cancer, perception of occurrence, and behavior in relation to breast self-examination (BSE). METHODS: A cross-sectional survey was carried out at the Department of Pathology, Medical College, University of Hail, Hail, Kingdom of Saudi Arabia for local occupants from Hail city and its rural neighborhood between September 2010 and February 2012. A personal interview-administered descriptive questionnaire and both descriptive and inferential statistics were used. RESULTS: A total of 1000 participants agreed to be involved, out of which 87.7% were females, 7.2% were males and 5.1% had undisclosed gender. The age range for participants was 12-66 years. Out of all participants, 44% did not know that breast cancer is an abnormal growth and 78% failed to recognise its multi-factorial nature, with Increased age being the least recognised single risk factor 4.8%. Scores showed that 61.5% had a low level of breast cancer related knowledge. Out of the participants who knew of someone who had breast cancer 73%, 50.1% said the disease was discovered at a Late stage mainly by Chance. Data for BSE indicated that 50.1% of female participants >16 years old did not practice BSE, and Fear was the main declared perceived reason. CONCLUSION: This study demonstrates a low level of fundamental knowledge of breast cancer and fear to practice BSE.

Binary interaction dominates the evolution of massive stars.

The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.