Using AI and computer vision to analyze technical proficiency in robotic surgery.

BACKGROUND: Intraoperative skills assessment is time-consuming and subjective; an efficient and objective computer vision-based approach for feedback is desired. In this work, we aim to design and validate an interpretable automated method to evaluate technical proficiency using colorectal robotic surgery videos with artificial intelligence. METHODS: 92 curated clips of peritoneal closure were characterized by both board-certified surgeons and a computer vision AI algorithm to compare the measures of surgical skill. For human ratings, six surgeons graded clips according to the GEARS assessment tool; for AI assessment, deep learning computer vision algorithms for surgical tool detection and tracking were developed and implemented. RESULTS: For the GEARS category of efficiency, we observe a positive correlation between human expert ratings of technical efficiency and AI-determined total tool movement (r = - 0.72). Additionally, we show that more proficient surgeons perform closure with significantly less tool movement compared to less proficient surgeons (p < 0.001). For the GEARS category of bimanual dexterity, a positive correlation between expert ratings of bimanual dexterity and the AI model's calculated measure of bimanual movement based on simultaneous tool movement (r = 0.48) was also observed. On average, we also find that higher skill clips have significantly more simultaneous movement in both hands compared to lower skill clips (p < 0.001). CONCLUSIONS: In this study, measurements of technical proficiency extracted from AI algorithms are shown to correlate with those given by expert surgeons. Although we target measurements of efficiency and bimanual dexterity, this work suggests that artificial intelligence through computer vision holds promise for efficiently standardizing grading of surgical technique, which may help in surgical skills training.

Laparoscopic Heller Myotomy and Toupet Fundoplication.

Esophageal achalasia is a primary motility disorder of unknown origin. The goal of treatment is to eliminate the resistance caused by a non-relaxing lower esophageal sphincter, therefore allowing passage of food and liquid from the esophagus into the stomach. A myotomy with a partial fundoplication (anterior Dor or posterior Toupet) is considered the standard of care for patients with achalasia. In the following review, we describe the indications and technique for a posterior partial fundoplication (Toupet).

Impact of COVID-19 on presentation, management, and outcomes of acute care surgery for gallbladder disease and acute appendicitis.

BACKGROUND: The ongoing coronavirus disease 2019 (COVID-19) pandemic has significantly disrupted both elective and acute medical care. Data from the early months suggest that acute care patient populations deferred presenting to the emergency department (ED), portending more severe disease at the time of presentation. Additionally, care for this patient population trended towards initial non-operative management. AIM: To examine the presentation, management, and outcomes of patients who developed gallbladder disease or appendicitis during the pandemic. METHODS: A retrospective chart review of patients diagnosed with acute cholecystitis, symptomatic cholelithiasis, or appendicitis in two EDs affiliated with a single tertiary academic medical center in Northern California between March and June, 2020 and in the same months of 2019. Patients were selected through a research repository using international classification of diseases (ICD)-9 and ICD-10 codes. Across both years, 313 patients were identified with either type of gallbladder disease, while 361 patients were identified with acute appendicitis. The primary outcome was overall incidence of disease. Secondary outcomes included presentation, management, complications, and 30-d re-presentation rates. Relationships between different variables were explored using Pearson's r correlation coefficient. Variables were compared using the Welch's t-Test, Chi-squared tests, and Fisher's exact test as appropriate. RESULTS: Patients with gallbladder disease and appendicitis both had more severe presentations in 2020. With respect to gallbladder disease, more patients in the COVID-19 cohort presented with acute cholecystitis compared to the control cohort [50% (80) vs 35% (53); P = 0.01]. Patients also presented with more severe cholecystitis in 2020 as indicated by higher mean Tokyo Criteria Scores [mean (SD) 1.39 (0.56) vs 1.16 (0.44); P = 0.02]. With respect to appendicitis, more patients were diagnosed with a perforated appendix at presentation in 2020 [20% (36) vs 16% (29); P = 0.02] and a greater percentage were classified as emergent cases using the emergency severity index [63% (112) vs 13% (23); P < 0.001]. While a greater percentage of patients were admitted to the hospital for gallbladder disease in 2020 [65% (104) vs 50% (76); P = 0.02], no significant differences were observed in hospital admissions for patients with appendicitis. No significant differences were observed in length of hospital stay or operative rate for either group. However, for patients with appendicitis, 30-d re-presentation rates were significantly higher in 2020 [13% (23) vs 4% (8); P = 0.01]. CONCLUSION: During the COVID-19 pandemic, patients presented with more severe gallbladder disease and appendicitis. These findings suggest that the pandemic has affected patients with acute surgical conditions.

Surgical deserts in California: an analysis of access to surgical care.

BACKGROUND: Areas of minimal access to surgical care, often called "surgical deserts", are of particular concern when considering the need for urgent surgical and anesthesia care. We hypothesized that California would have an appropriate workforce density but that physicians would be concentrated in urban areas, and surgical deserts would exist in rural counties. METHODS: We used a benchmark of six general surgeons, six orthopedists, and eight anesthesiologists per 100,000 people per county to define a "desert". The number and location of these providers were obtained from the Medical Board of California for 2015. ArcGIS, version 10.3, was used to geocode the data and were analyzed in Redivis. RESULTS: There were a total of 3268 general surgeons, 3188 orthopedists, and 5995 anesthesiologists in California in 2015, yielding a state surgeon-to-population ratio of 7.2, 6.7, and 10.2 per 100,000 people, respectively; however, there was wide geographic variability. Of the 58 counties in California, 18 (31%) have a general surgery desert, 27 (47%) have an orthopedic desert, and 22 (38%) have an anesthesiology desert. These counties account for 15%, 25%, and 13% of the state population, respectively. Five, seven, and nine counties, respectively, have none in the corresponding specialty. CONCLUSIONS: Overall, California has an adequate ratio of surgical and anesthesia providers to population. However, because of their uneven distribution, significant surgical care deserts exist. Limited access to surgical and anesthesia providers may negatively impact patient outcome in these counties.

Why do patients receive care from a short-term medical mission? Survey study from rural Guatemala.

BACKGROUND: Hospital de la Familia was established to serve the indigent population in the western highlands of Guatemala and has a full-time staff of Guatemalan primary care providers supplemented by short-term missions of surgical specialists. The reasons for patients seeking surgical care in this setting, as opposed to more consistent care from local institutions, are unclear. We sought to better understand motivations of patients seeking mission-based surgical care. METHODS: Patients presenting to the obstetric and gynecologic, plastic, ophthalmologic, general, and pediatric surgical clinics at the Hospital de la Familia from July 27 to August 6, 2015 were surveyed. The surveys assessed patient demographics, surgical diagnosis, location of home, mode of travel, and reasons for seeking care at this facility. RESULTS: Of 252 patients surveyed, 144 (59.3%) were female. Most patients reported no other medical condition (67.9%, n = 169) and no consistent income (83.9%, n = 209). Almost half (44.9%, n = 109) traveled >50 km to receive care. The most common reasons for choosing care at this facility were reputation of high quality (51.8%, n = 130) and affordability (42.6%, n = 102); the least common reason was a lack of other options (6.4%, n = 16). CONCLUSIONS: Despite long travel distances and the availability of other options, reputation and affordability were primarily cited as the most common reasons for choosing to receive care at this short-term surgical mission site. Our results highlight that although other surgical options may be closer and more readily available, reputation and cost play a large role in choice of patients seeking care.

A geospatial evaluation of timely access to surgical care in seven countries.

OBJECTIVE: To assess the consistent availability of basic surgical resources at selected facilities in seven countries. METHODS: In 2010-2014, we used a situational analysis tool to collect data at district and regional hospitals in Bangladesh (n = 14), the Plurinational State of Bolivia (n = 18), Ethiopia (n = 19), Guatemala (n = 20), the Lao People's Democratic Republic (n = 12), Liberia (n = 12) and Rwanda (n = 25). Hospital sites were selected by pragmatic sampling. Data were geocoded and then analysed using an online data visualization platform. Each hospital's catchment population was defined as the people who could reach the hospital via a vehicle trip of no more than two hours. A hospital was only considered to show consistent availability of basic surgical resources if clean water, electricity, essential medications including intravenous fluids and at least one anaesthetic, analgesic and antibiotic, a functional pulse oximeter, a functional sterilizer, oxygen and providers accredited to perform surgery and anaesthesia were always available. FINDINGS: Only 41 (34.2%) of the 120 study hospitals met the criteria for the provision of consistent basic surgical services. The combined catchments of the study hospitals in each study country varied between 3.3 million people in Liberia and 151.3 million people in Bangladesh. However, the combined catchments of the study hospitals in each study country that met the criteria for the provision of consistent basic surgical services were substantially smaller and varied between 1.3 million in Liberia and 79.2 million in Bangladesh. CONCLUSION: Many study facilities were deficient in the basic infrastructure necessary for providing basic surgical care on a consistent basis.

The prevalence of psychiatric diagnoses and associated mortality in hospitalized US trauma patients.

BACKGROUND: We hypothesized that psychiatric diagnoses would be common in hospitalized trauma patients in the United States and when present, would be associated with worse outcomes. MATERIALS AND METHODS: The Nationwide Inpatient Sample (NIS, 2012) was used to determine national estimates for the number of patients admitted with an injury. Psychiatric diagnoses were identified using diagnosis codes according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. RESULTS: A total of 36.5 million patients were admitted to hospitals in the United States in 2012. Of these, 1.3 million (4%) were due to trauma. Psychiatric conditions were more common in patients admitted for trauma versus those admitted for other reasons (44% versus 34%, P < 0.001). Trauma patients who had a psychiatric diagnosis compared to trauma patients without a psychiatric diagnosis were older (mean age: 61 versus 56 y, P < 0.001), more often female (52% versus 50%, P < 0.001), and more often white (73% versus 68%, P < 0.001). For ages 18-64, drug and alcohol abuse predominated (41%), whereas dementia and related disorders (48%) were the most common in adults ≥65 y. Mortality was lower for trauma patients with a psychiatric diagnosis compared to those who did not in both unadjusted and adjusted analysis (1.9% versus 2.8%; odds ratio: 0.56, P < 0.001). CONCLUSIONS: Psychiatric conditions are present in almost half of all hospitalized trauma patients in the United States; however, the types of conditions varied with age. The frequency of psychiatric conditions in the trauma population suggests efforts should be made to address this component of patient health.

The American College of Surgeons Needs-Based Assessment of Trauma Systems: Estimates for the State of California.

BACKGROUND: In 2015, the American College of Surgeons Committee on Trauma convened a consensus conference to develop the Needs-Based Assessment of Trauma Systems (NBATS) tool to assist in determining the number of trauma centers required for a region. We tested the performance of NBATS with respect to the optimal number of trauma centers needed by region in California. METHODS: Trauma center data were obtained from the California Emergency Services Authority Information Systems (CEMSIS). Numbers of admitted trauma patients (ISS > 15) were obtained using statewide nonpublic admissions data from the California Office of Statewide Health Planning and Development (OSHPD), CEMSIS, and data from local emergency medical service agency (LEMSA) directors who agreed to participate in a telephone survey. Population estimates per county for 2014 were obtained from the U.S. Census. NBATS criteria used included population, transport time, community support, and number of discharges for severely injured patients (ISS > 15) at nontrauma centers and trauma centers. Estimates for the number of trauma centers per region were created for each of the three data sources and compared to the number of existing centers. RESULTS: A total of 62 state-designated trauma centers were identified for California: 13 (21%) Level I, 36 (58%) Level II, and 13 (11%) Level III. NBATS estimates for the total number of trauma centers in California were 27% to 47% lower compared to the number of trauma centers in existence, but this varied based on urban/rural status. NBATS estimates were lower than the current state in 70% of urban areas but were higher in almost 90% of rural areas. All data sources (OSHPD, CEMSIS, local data) produced similar results. CONCLUSION: Estimates from the NBATS tool are different from what is currently in existence in California, and differences exist based on whether the region is rural or urban. Findings from the current study can help inform future iterations of the NBATS tool. LEVEL OF EVIDENCE: Economic, level V.

Prevalence and predictors of depression among general surgery residents.

BACKGROUND: Recent resident suicides have highlighted the need to address depression among medical trainees. This study sought to identify the prevalence and predictors of depression among surgical residents. METHODS: Surgical residents at a single institution were surveyed. Depression and personal traits were assessed using validated measures; participant demographics were also obtained. RESULTS: 73 residents completed the survey (response rate 63%). 36% met criteria for at least mild depression, of which 20% met criteria for moderate to severe depression. In multivariate linear regression analyses controlling for demographic factors, trait emotional intelligence alone was a significant inverse predictor of depression (ß = -0.60, p < 0.001). CONCLUSIONS: Depression is prevalent among general surgery residents. Identifying protective factors and at-risk populations may allow for effective initiatives to be developed to address depression, and optimize the mental health of trainees.

Mapping Disparities in Access to Safe, Timely, and Essential Surgical Care in Zambia.

Importance: Surgical care is widely unavailable in developing countries; advocates recommend that countries evaluate and report on access to surgical care to improve availability and aid health planners in decision making. Objective: To analyze the infrastructure, capacity, and availability of surgical care in Zambia to inform health policy priorities. Design, Setting, and Participants: In this observational study, all hospitals providing surgical care were identified in cooperation with the Zambian Ministry of Health. On-site data collection was conducted from February 1 through August 30, 2011, with an adapted World Health Organization Global Initiative for Emergency and Essential Surgical Care survey. Data collection at each facility included interviews with hospital personnel and assessment of material resources. Data were geocoded and analyzed in a data visualization platform from March 1 to December 1, 2015. We analyzed time and distance to surgical services, as well as the proportion of the population living within 2 hours from a facility providing surgical care. Main Outcomes and Measures: Surgical capacity, supplies, human resources, and infrastructure at each surgical facility, as well as the population living within 2 hours from a hospital providing surgical care. Results: Data were collected from all 103 surgical facilities identified as providing surgical care. When including all surgical facilities (regardless of human resources and supplies), 14.9% of the population (2 166 460 of 14 500 000 people) lived more than 2 hours from surgical care. However, only 17 hospitals (16.5%) met the World Health Organization minimum standards of surgical safety; when limiting the analysis to these hospitals, 65.9% of the population (9 552 780 people) lived in an area that was more than 2 hours from a surgical facility. Geographic analysis of emergency and essential surgical care, defined as access to trauma care, obstetric care, and care of common abdominal emergencies, found that 80.7% of the population (11 704 700 people) lived in an area that was more than 2 hours from these surgical facilities. Conclusions and Relevance: A large proportion of the population in Zambia does not have access to safe and timely surgical care; this percentage would change substantially if all surgical hospitals were adequately resourced. Geospatial visualization tools assist in the evaluation of surgical infrastructure in Zambia and can identify key areas for improvement.

Size and distribution of the global volume of surgery in 2012.

OBJECTIVE: To estimate global surgical volume in 2012 and compare it with estimates from 2004. METHODS: For the 194 Member States of the World Health Organization, we searched PubMed for studies and contacted key informants for reports on surgical volumes between 2005 and 2012. We obtained data on population and total health expenditure per capita for 2012 and categorized Member States as very-low, low, middle and high expenditure. Data on caesarean delivery were obtained from validated statistical reports. For Member States without recorded surgical data, we estimated volumes by multiple imputation using data on total health expenditure. We estimated caesarean deliveries as a proportion of all surgery. FINDINGS: We identified 66 Member States reporting surgical data. We estimated that 312.9 million operations (95% confidence interval, CI: 266.2-359.5) took place in 2012, an increase from the 2004 estimate of 226.4 million operations. Only 6.3% (95% CI: 1.7-22.9) and 23.1% (95% CI: 14.8-36.7) of operations took place in very-low- and low-expenditure Member States representing 36.8% (2573 million people) and 34.2% (2393 million people) of the global population of 7001 million people, respectively. Caesarean deliveries comprised 29.6% (5.8/19.6 million operations; 95% CI: 9.7-91.7) of the total surgical volume in very-low-expenditure Member States, but only 2.7% (5.1/187.0 million operations; 95% CI: 2.2-3.4) in high-expenditure Member States. CONCLUSION: Surgical volume is large and growing, with caesarean delivery comprising nearly a third of operations in most resource-poor settings. Nonetheless, there remains disparity in the provision of surgical services globally.

Variability in mortality following caesarean delivery, appendectomy, and groin hernia repair in low-income and middle-income countries: a systematic review and analysis of published data.

BACKGROUND: Surgical interventions occur at lower rates in resource-poor settings, and complication and death rates following surgery are probably substantial but have not been well quantified. A deeper understanding of outcomes is a crucial step to ensure that high quality accompanies increased global access to surgical care. We aimed to assess surgical mortality following three common surgical procedures--caesarean delivery, appendectomy, and groin (inguinal and femoral) hernia repair--to quantify the potential risks of expanding access without simultaneously addressing issues of quality and safety. METHODS: We collected demographic, health, and economic data for 113 countries classified as low income or lower-middle income by the World Bank in 2005. We did a systematic review of Ovid, MEDLINE, PubMed, and Scopus from Jan 1, 2000, to Jan 15, 2015, to identify studies in these countries reporting all-cause mortality following the three commonly undertaken operations. Reports from governmental and other agencies were also identified and included. We modelled surgical mortality rates for countries without reported data using a two-step multiple imputation method. We first used a fully conditional specification (FCS) multiple imputation method to establish complete datasets for all missing variables that we considered potentially predictive of surgical mortality. We then used regression-based predictive mean matching imputation methods, specified within the multiple imputation FCS method, for selected predictors for each operation using the completed dataset to predict mortality rates along with confidence intervals for countries without reported mortality data. To account for variability in data availability, we aggregated results by subregion and estimated surgical mortality rates. FINDINGS: From an initial 1302 articles and reports identified, 247 full-text articles met our inclusion criteria, and 124 provided data for surgical mortality for at least one of the three selected operations. We identified 42 countries with mortality data for at least one of the three procedures. Median reported mortality was 7·9 per 1000 operations for caesarean delivery (IQR 2·8-19·9), 2·2 per 1000 operations for appendectomy (0·0-17·2), and 4·9 per 1000 operations for groin hernia (0·0-11·7). Perioperative mortality estimates by subregion ranged from 2·8 (South Asia) to 50·2 (East Asia) per 1000 caesarean deliveries, 2·4 (South Asia) to 54·0 (Central sub-Saharan Africa) per 1000 appendectomies, and 0·3 (Andean Latin America) to 25·5 (Southern sub-Saharan Africa) per 1000 hernia repairs. INTERPRETATION: All-cause postoperative mortality rates are exceedingly variable within resource-constrained environments. Efforts to expand surgical access and provision of services must include a strong commitment to improve the safety and quality of care. FUNDING: None.

Relationship Between Cesarean Delivery Rate and Maternal and Neonatal Mortality.

IMPORTANCE: Based on older analyses, the World Health Organization (WHO) recommends that cesarean delivery rates should not exceed 10 to 15 per 100 live births to optimize maternal and neonatal outcomes. OBJECTIVES: To estimate the contemporary relationship between national levels of cesarean delivery and maternal and neonatal mortality. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional, ecological study estimating annual cesarean delivery rates from data collected during 2005 to 2012 for all 194 WHO member states. The year of analysis was 2012. Cesarean delivery rates were available for 54 countries for 2012. For the 118 countries for which 2012 data were not available, the 2012 cesarean delivery rate was imputed from other years. For the 22 countries for which no cesarean rate data were available, the rate was imputed from total health expenditure per capita, fertility rate, life expectancy, percent of urban population, and geographic region. EXPOSURES: Cesarean delivery rate. MAIN OUTCOMES AND MEASURES: The relationship between population-level cesarean delivery rate and maternal mortality ratios (maternal death from pregnancy related causes during pregnancy or up to 42 days postpartum per 100,000 live births) or neonatal mortality rates (neonatal mortality before age 28 days per 1000 live births). RESULTS: The estimated number of cesarean deliveries in 2012 was 22.9 million (95% CI, 22.5 million to 23.2 million). At a country-level, cesarean delivery rate estimates up to 19.1 per 100 live births (95% CI, 16.3 to 21.9) and 19.4 per 100 live births (95% CI, 18.6 to 20.3) were inversely correlated with maternal mortality ratio (adjusted slope coefficient, -10.1; 95% CI, -16.8 to -3.4; P = .003) and neonatal mortality rate (adjusted slope coefficient, -0.8; 95% CI, -1.1 to -0.5; P < .001), respectively (adjusted for total health expenditure per capita, population, percent of urban population, fertility rate, and region). Higher cesarean delivery rates were not correlated with maternal or neonatal mortality at a country level. A sensitivity analysis including only 76 countries with the highest-quality cesarean delivery rate information had a similar result: cesarean delivery rates greater than 6.9 to 20.1 per 100 live births were inversely correlated with the maternal mortality ratio (slope coefficient, -21.3; 95% CI, -32.2 to -10.5, P < .001). Cesarean delivery rates of 12.6 to 24.0 per 100 live births were inversely correlated with neonatal mortality (slope coefficient, -1.4; 95% CI, -2.3 to -0.4; P = .004). CONCLUSIONS AND RELEVANCE: National cesarean delivery rates of up to approximately 19 per 100 live births were associated with lower maternal or neonatal mortality among WHO member states. Previously recommended national target rates for cesarean deliveries may be too low.

Estimate of the global volume of surgery in 2012: an assessment supporting improved health outcomes.

BACKGROUND: It was previously estimated that 234·2 million operations were performed worldwide in 2004. The association between surgical rates and population health outcomes is not clear. We re-estimated global surgical volume to track changes over time and assess rates associated with healthy populations. METHODS: We gathered demographic, health, and economic data for 194 WHO member states. Surgical volumes were obtained from published studies and other reports from 2005 onwards. We estimated rates of surgery for all countries without available data based on health expenditure in 2012 and assessed the proportion of surgery comprised by caesarean delivery. The rate of surgery was plotted against life expectancy to describe the association between surgical care and this health indicator. FINDINGS: We identified 66 countries reporting surgical data between 2005 and 2013. We estimate that 312·9 million operations (95% CI 266·2-359·5) took place in 2012-a 33·6% increase over 8 years; the largest proportional increase occurred in countries spending US$400 or less per capita on health care. Caesarean delivery comprised 29·8% (5·8 million operations) of the total surgical volume in poor health expenditure countries compared with 10·8% (7·8 million operations) in low health expenditure countries and 2·7% (5·1 million operations) in high health expenditure countries. We noted a correlation between increased life expectancy and increased surgical rates up to 1533 operations per 100 000 people, with significant but less dramatic improvement above this rate. INTERPRETATION: Surgical volume is large and continues to grow in all economic environments. A single procedure-caesarean delivery-comprised almost a third of surgical volume in the most resource-limited settings. Surgical care is an essential part of health care and is associated with increased life expectancy, yet many low-income countries fail to achieve basic levels of service. Improvements in capacity and delivery of surgical services must be a major component of health system strengthening. FUNDING: None.

Proposed minimum rates of surgery to support desirable health outcomes: an observational study based on four strategies.

BACKGROUND: The global volume of surgery in 2012 is estimated at 312·9 million operations per year, but rates of surgery vary substantially. Maternal health advocates proposed minimum caesarean delivery rates for benchmarking and to improve perinatal outcomes; however, this has not been done for surgery because the association between rates of surgical care provision as a whole and population health outcomes have not been well described. We use available data to estimate minimum rates of surgery that are associated with important health indicators. METHODS: We defined surgical operations as procedures done in operating theatres that need general or regional anaesthesia or profound sedation to control pain. We used four strategies to identify rates of surgery based on estimated rates of surgery per country for 2012 associated with life expectancy of 74-75 years; estimated rates of surgery associated with a maternal mortality ratio of less than or equal to 100 per 100 000 live births; estimated minimum need for surgery in the 21 Global Burden of Disease (GBD) regions based on the prevalence of disorders; and surgical rates from the so-called 4C countries (Chile, China, Costa Rica, and Cuba) identified in The Lancet Commission on Global Surgery as exemplary for their achievement of high health status, despite resource limitations. FINDINGS: Based on 2012 national surgical rates, countries with reported life expectancy of 74-75 years (n=17) had a median surgical rate of 4392 (IQR 2897-4873) operations per 100 000 population annually. The median surgical rate associated with maternal mortality ratio lower than 100 (n=109) is 5028 (IQR 4139-6778) operations per 100 000 population annually. The median surgical rate estimated for all 21 GBD regions was 4669 (IQR 4339-5291) operations per 100 000 population annually. The 4C countries had a mean surgical rate of 4344 (95% CI 2620-6068) operations per 100 000 population annually. 13 of the 21 GBD regions, accounting for 78% of the world's population, do not achieve the lowest end of the surgical rate range. INTERPRETATION: We identified a surprisingly narrow range of surgical rates associated with important health indicators. This target range can be used for benchmarking of surgical services, and as part of a policy aimed at strengthening health-care systems and surgical capacity. FUNDING: None.

Projections to achieve minimum surgical rate threshold: an observational study.

BACKGROUND: Recent work has indicated an increase in surgical services, especially in resource poor settings. However, the rate of growth is poorly understood and likely insufficient to meet public health needs. We previously identified a range of 4344 to 5028 operations per 100 000 population annually to be related to desirable health outcomes. From this and other evidence, the Lancet Commission on Global Surgery recommends a minimum rate of 5000 operations per 100 000 population. We evaluate rates of growth in surgery and estimate the time it will take to reach this minimum surgical rate threshold. METHODS: We aggregated 2004 and 2012 country-level surgical rate estimates into the 21 Global Burden of Disease (GBD) regions. We calculated mean rates of surgery proportional to population size and estimate rate of growth between these years. We then extrapolated the time it will take to reach a surgical rate of 5000 operations per 100 000 population based on linear rates of change. FINDINGS: All but two regions (central Europe and southern Latin America) experienced growth in their surgical rates during the past 8 years; the fastest growth occurred in regions with the lowest surgical rates. 14 regions representing 79% of the world's population (5·5 billion people) did not meet the recommended surgical rate threshold in 2012. If surgical capacity grows at current rates, seven regions (central sub-Saharan Africa, east Asia, eastern sub-Saharan Africa, north Africa and middle east, south Asia, southeast Asia, and western sub-Saharan Africa) will not meet the recommended surgical rate threshold by 2035; Eastern Sub-Saharan Africa will not reach this level until 2124. INTERPRETATION: The rates of growth in surgical service delivery are exceedingly variable, but the largest growth rates were noted in the poorest regions. Although this study does not address the quality of care, and rates of surgery are unlikely to change linearly, this exercise is useful to project how many years it could take regions to reach specific surgical rates. At current rates of growth, 4·9 billion people (70% of the world's population) will still be living in countries below the minimum recommended rate of surgery in 2035. A strategy for strengthening surgical capacity is essential if these targets are to be met as part of integrated health system development. FUNDING: None.

Avoidable maternal and neonatal deaths associated with improving access to caesarean delivery in countries with low caesarean delivery rates: an ecological modelling analysis.

BACKGROUND: Reducing maternal and neonatal deaths are important global health priorities. We have previously shown that up to a country-level caesarean delivery rate (CDRs) of roughly 19·0%, cesarean delivery rates and maternal mortality ratio (MMR) and neonatal mortality rate (NMR) were inversely correlated. We investigated the absolute reductions in maternal and neonatal deaths if countries with low CDR increased their rates to a range of greater than 7·2% but less than or equal to 19·1%. METHODS: We calculated maternal and neonatal deaths in 2013 and 2012, respectively, for countries with CDR 7·2% or less (N=45) with available data from the World Bank Development Indicators. We modelled the expected reduction in deaths in these countries if they had the 25th and 75th MMR and NMR percentiles observed for countries (N=48) with CDRs ranging from greater than 7·2% but less than or equal to 19·1%. This model assumes that if countries with low CDRs increased their rates of caesarean delivery to greater than 7·2% but less than or equal to 19·1%, they would achieve levels of MMR and NMR observed in countries with those CDRs. FINDINGS: We estimate 176 078 (95% CI 163 258-188 898) maternal and 1 117 257 (95% CI 1 033 611-1 200 902) neonatal deaths occurred in 45 countries with low CDRs in 2013 and 2012, respectively. If these countries had the 25th and 75th MMR and NMR percentiles (MMR, IQR 36-190; NMR, 9-24) observed in countries (N=48) with a CDR ranging from greater than 7·2% but less than or equal to 19·1%, there would be a potential reduction of 109 762-163 513 and 279 584-803 129 maternal and neonatal deaths, respectively. INTERPRETATION: Increasing caesarean delivery in countries with low CDRs could avert as many as 163 513 maternal deaths and 803 129 neonatal deaths annually. These findings assume that as health systems develop the capacity to deliver surgical care, there is a concurrent improvement in the quality of care and in the ability to rescue women and neonates who would otherwise die. Improving access to safe caesarean delivery should be a central focus in surgical care globally. FUNDING: None.