A dynamical measure of the black hole mass in a quasar 11 billion years ago.

Tight relationships exist in the local Universe between the central stellar properties of galaxies and the mass of their supermassive black hole (SMBH)1-3. These suggest that galaxies and black holes co-evolve, with the main regulation mechanism being energetic feedback from accretion onto the black hole during its quasar phase4-6. A crucial question is how the relationship between black holes and galaxies evolves with time; a key epoch to examine this relationship is at the peaks of star formation and black hole growth 8-12 billion years ago (redshifts 1-3)7. Here we report a dynamical measurement of the mass of the black hole in a luminous quasar at a redshift of 2, with a look back in time of 11 billion years, by spatially resolving the broad-line region (BLR). We detect a 40-µas (0.31-pc) spatial offset between the red and blue photocentres of the Hα line that traces the velocity gradient of a rotating BLR. The flux and differential phase spectra are well reproduced by a thick, moderately inclined disk of gas clouds within the sphere of influence of a central black hole with a mass of 3.2 × 108 solar masses. Molecular gas data reveal a dynamical mass for the host galaxy of 6 × 1011 solar masses, which indicates an undermassive black hole accreting at a super-Eddington rate. This suggests a host galaxy that grew faster than the SMBH, indicating a delay between galaxy and black hole formation for some systems.

Suppression of black-hole growth by strong outflows at redshifts 5.8-6.6.

Bright quasars, powered by accretion onto billion-solar-mass black holes, already existed at the epoch of reionization, when the Universe was 0.5-1 billion years old1. How these black holes formed in such a short time is the subject of debate, particularly as they lie above the correlation between black-hole mass and galaxy dynamical mass2,3 in the local Universe. What slowed down black-hole growth, leading towards the symbiotic growth observed in the local Universe, and when this process started, has hitherto not been known, although black-hole feedback is a likely driver4. Here we report optical and near-infrared observations of a sample of quasars at redshifts 5.8 ≲ z ≲ 6.6. About half of the quasar spectra reveal broad, blueshifted absorption line troughs, tracing black-hole-driven winds with extreme outflow velocities, up to 17% of the speed of light. The fraction of quasars with such outflow winds at z ≳ 5.8 is ≈2.4 times higher than at z ≈ 2-4. We infer that outflows at z ≳ 5.8 inject large amounts of energy into the interstellar medium and suppress nuclear gas accretion, slowing down black-hole growth. The outflow phase may then mark the beginning of substantial black-hole feedback. The red optical colours of outflow quasars at z ≳ 5.8 indeed suggest that these systems are dusty and may be caught during an initial quenching phase of obscured accretion5.

The effects of short-term, progressive exercise training on disease activity in smouldering multiple myeloma and monoclonal gammopathy of undetermined significance: a single-arm pilot study.

BACKGROUND: High levels of physical activity are associated with reduced risk of the blood cancer multiple myeloma (MM). MM is preceded by the asymptomatic stages of monoclonal gammopathy of undetermined significance (MGUS) and smouldering multiple myeloma (SMM) which are clinically managed by watchful waiting. A case study (N = 1) of a former elite athlete aged 44 years previously indicated that a multi-modal exercise programme reversed SMM disease activity. To build from this prior case study, the present pilot study firstly examined if short-term exercise training was feasible and safe for a group of MGUS and SMM patients, and secondly investigated the effects on MGUS/SMM disease activity. METHODS: In this single-arm pilot study, N = 20 participants diagnosed with MGUS or SMM were allocated to receive a 16-week progressive exercise programme. Primary outcome measures were feasibility and safety. Secondary outcomes were pre- to post-exercise training changes to blood biomarkers of MGUS and SMM disease activity- monoclonal (M)-protein and free light chains (FLC)- plus cardiorespiratory and functional fitness, body composition, quality of life, blood immunophenotype, and blood biomarkers of inflammation. RESULTS: Fifteen (3 MGUS and 12 SMM) participants completed the exercise programme. Adherence was 91 ± 11%. Compliance was 75 ± 25% overall, with a notable decline in compliance at intensities > 70% V̇O2PEAK. There were no serious adverse events. There were no changes to M-protein (0.0 ± 1.0 g/L, P =.903), involved FLC (+ 1.8 ± 16.8 mg/L, P =.839), or FLC difference (+ 0.2 ± 15.6 mg/L, P =.946) from pre- to post-exercise training. There were pre- to post-exercise training improvements to diastolic blood pressure (- 3 ± 5 mmHg, P =.033), sit-to-stand test performance (+ 5 ± 5 repetitions, P =.002), and energy/fatigue scores (+ 10 ± 15%, P =.026). Other secondary outcomes were unchanged. CONCLUSIONS: A 16-week progressive exercise programme was feasible and safe, but did not reverse MGUS/SMM disease activity, contrasting a prior case study showing that five years of exercise training reversed SMM in a 44-year-old former athlete. Longer exercise interventions should be explored in a group of MGUS/SMM patients, with measurements of disease biomarkers, along with rates of disease progression (i.e., MGUS/SMM to MM). REGISTRATION: https://www.isrctn.com/ISRCTN65527208 (14/05/2018).

Two separate outflows in the dual supermassive black hole system NGC 6240.

Theoretical models and numerical simulations have established a framework of galaxy evolution in which galaxies merge and create dual supermassive black holes (with separations of one to ten kiloparsecs), which eventually sink into the centre of the merger remnant, emit gravitational waves and coalesce. The merger also triggers star formation and supermassive black hole growth, and gas outflows regulate the stellar content1-3. Although this theoretical picture is supported by recent observations of starburst-driven and supermassive black hole-driven outflows4-6, it remains unclear how these outflows interact with the interstellar medium. Furthermore, the relative contributions of star formation and black hole activity to galactic feedback remain unknown7-9. Here we report observations of dual outflows in the central region of the prototypical merger NGC 6240. We find a black-hole-driven outflow of [O III] to the northeast and a starburst-driven outflow of Hα to the northwest. The orientations and positions of the outflows allow us to isolate them spatially and study their properties independently. We estimate mass outflow rates of 10 and 75 solar masses per year for the Hα bubble and the [O III] cone, respectively. Their combined mass outflow is comparable to the star formation rate 10 , suggesting that negative feedback on star formation is occurring.

Measuring and increasing rates of self-isolation in the context of COVID-19: a systematic review with narrative synthesis.

OBJECTIVES: This study aimed to investigate (1) definitions of self-isolation used during the COVID-19 pandemic; (2) measures used to quantify adherence and their reliability, validity, and acceptability; (3) rates of self-isolation adherence; and (4) factors associated with adherence. STUDY DESIGN: This was a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Synthesis Without Meta-analysis (PRISMA) guidelines (PROSPERO record CRD42022377820). METHODS: MEDLINE, PsycINFO, Embase, Web of Science, PsyArXiv, medRxiv, and grey literature sources were searched (1 January 2020 to 13 December 2022) using terms related to COVID-19, isolation, and adherence. Studies were included if they contained original, quantitative data of self-isolation adherence during the COVID-19 pandemic. We extracted definitions of self-isolation, measures used to quantify adherence, adherence rates, and factors associated with adherence. RESULTS: We included 45 studies. Self-isolation was inconsistently defined. Four studies did not use self-report measures. Of 41 studies using self-report, one reported reliability; another gave indirect evidence for the lack of validity of the measure. Rates of adherence to self-isolation for studies with only some concerns of bias were 51%-86% for COVID-19 cases, 78%-94% for contacts, and 16% for people with COVID-19-like symptoms. There was little evidence that self-isolation adherence was associated with sociodemographic or psychological factors. CONCLUSIONS: There was no consensus in defining, operationalising, or measuring self-isolation, resulting in significant risk of bias in included studies. Future definitions of self-isolation should state behaviours to be enacted and duration. People recommended to self-isolate should be given support. Public health campaigns should aim to increase perceived effectiveness of self-isolation and promote accurate information about susceptibility to infection.

Factors influencing medium- and long-term occupational impact following COVID-19.

BACKGROUND: Significant numbers of individuals struggle to return to work following acute coronavirus disease 2019 (COVID-19). The UK Military developed an integrated medical and occupational pathway (Defence COVID-19 Recovery Service, DCRS) to ensure safe return to work for those with initially severe disease or persistent COVID-19 sequalae. Medical deployment status (MDS) is used to determine ability to perform job role without restriction ('fully deployable', FD) or with limitations ('medically downgraded', MDG). AIMS: To identify which variables differ between those who are FD and MDG 6 months after acute COVID-19. Within the downgraded cohort, a secondary aim is to understand which early factors are associated with persistent downgrading at 12 and 18 months. METHODS: Individuals undergoing DCRS had comprehensive clinical assessment. Following this, their electronic medical records were reviewed and MDS extracted at 6, 12 and 18 months. Fifty-seven predictors taken from DCRS were analysed. Associations were sought between initial and prolonged MDG. RESULTS: Three hundred and twenty-five participants were screened, with 222 included in the initial analysis. Those who were initially downgraded were more likely to have post-acute shortness of breath (SoB), fatigue and exercise intolerance (objective and subjective), cognitive impairment and report mental health symptoms. The presence of fatigue and SoB, cognitive impairment and mental health symptoms was associated with MDG at 12 months, and the latter two, at 18 months. There were also modest associations between cardiopulmonary function and sustained downgrading. CONCLUSIONS: Understanding the factors that are associated with initial and sustained inability to return to work allows individualized, targeted interventions to be utilized.

Coulomb Blockade in a Nonthermalized Quantum Dot.

We investigate nonequilibrium transport properties of a quantum dot in the Coulomb blockade regime under the condition of negligible inelastic scattering during the dwelling time of the electrons in the dot. Using the quantum kinetic equation we show that the absence of thermalization leads to a double step in the distribution function of electrons on the dot, provided that it is symmetrically coupled to the leads. This drastically changes nonlinear transport through the dot resulting in an additional (compared to the thermalized case) jump in the conductance at voltages close to the charging energy, which could serve as an experimental manifestation of the absence of thermalization.

Discontinuity of marginal artery at splenic flexure and rectosigmoid junction: A systematic review and meta-analysis.

AIM: The aim of this study was to provide comprehensive evidence-based assessment of the discontinuity of the marginal artery at the splenic flexure (SF) and the rectosigmoid junction (RSJ). METHOD: A systematic review was conducted of literature published to 26 December 2022 in the electronic databases PubMed, SCOPUS and Web of Science to identify studies eligible for inclusion. Data were extracted and pooled into a meta-analysis using the Metafor package in R. The primary outcomes were the pooled PPEs of the marginal artery at the SF and the RSJ. The secondary outcome was the size of vascular anastomoses. RESULTS: A total of 21 studies (n = 2,864 patients) were included. The marginal artery was present at the splenic flexure in 82% (95% CI: 62-95) of patients. Approximately 81% (95% CI: 63-94%) of patients had a large macroscopic anastomosis, while the remainder (19%) had small bridging ramifications forming the vessel. The marginal artery was present at the RSJ in 82% (95% CI: 70-91%) of patients. CONCLUSION: The marginal artery may be absent at the SF and the RSJ in up to 18% of individuals, which may confer a higher risk of ischaemic colitis. As a result of high interstudy heterogeneity noted in our analysis, further well-powered studies to clarify the prevalence of the marginal artery at the SF and the RSJ, as well as its relationship with other complementary colonic collaterals (intermediate and central mesenteric), are warranted.

Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago.

In the cold dark matter cosmology, the baryonic components of galaxies-stars and gas-are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius-a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe; and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early (high-redshift) Universe efficiently condensed at the centres of dark-matter haloes when gas fractions were high and dark matter was less concentrated.

Operative blood loss adversely affects short and long-term outcomes after colorectal cancer surgery: results of a systematic review and meta-analysis.

BACKGROUND: The aim of this meta-analysis was to assess the impact of operative blood loss on short and long-term outcomes following colorectal cancer surgery. METHODS: A systematic literature review and meta-analysis were performed, from inception to the 10th of August 2020. A comprehensive literature search was performed on the 10th of August 2020 of PubMed MEDLINE, Embase, Science Citation Index Expanded, and Cochrane Central Register of Controlled Trials. Only studies reporting on operative blood loss and postoperative short term or long-term outcomes in colorectal cancer surgery were considered for inclusion. RESULTS: Forty-three studies were included, reporting on 59,813 patients. Increased operative blood loss was associated with higher morbidity, for blood loss greater than 150-350 ml (odds ratio [OR] 2.09, p < 0.001) and > 500 ml (OR 2.29, p = 0.007). Anastomotic leak occurred more frequently for blood loss above a range of 50-100 ml (OR 1.14, p = 0.007), 250-300 ml (OR 2.06, p < 0.001), and 400-500 ml (OR 3.15, p < 0.001). Postoperative ileus rate was higher for blood loss > 100-200 ml (OR 1.90, p = 0.02). Surgical site infections were more frequent above 200-500 ml (OR 1.96, p = 0.04). Hospital stay was increased for blood loss > 150-200 ml (OR 1.63, p = 0.04). Operative blood loss was significantly higher in patients that suffered morbidity (mean difference [MD] 133.16 ml, p < 0.001) or anastomotic leak (MD 69.56 ml, p = 0.02). In the long term, increased operative blood loss was associated with worse overall survival above a range of 200-500 ml (hazard ratio [HR] 1.15, p < 0.001), and worse recurrence-free survival above 200-400 ml (HR 1.33, p = 0.01). Increased blood loss was associated with small bowel obstruction caused by colorectal cancer recurrence for blood loss higher than 400 ml (HR 1.97, p = 0.03) and 800 ml (HR 3.78, p = 0.02). CONCLUSIONS: Increased operative blood loss may adversely impact short term and long-term postoperative outcomes. Measures should be taken to minimize operative blood loss during colorectal cancer surgery. Due to the uncertainty of evidence identified, further research, with standardised methodology, is required on this important subject.

Renal replacement and extracorporeal therapies in critical care: current and future directions.

There are a wide number of indications for extracorporeal therapies in the critical care environment. A common indication seen by the acute physician is continuous renal replacement therapy (CRRT) in a proportion of patients with acute kidney injury. It is therefore important that acute physicians have a sound understanding of the principles of CRRT in the acutely unwell patient. This review will outline the indications for its use, commonly used methods and anticoagulation considerations. It will discuss when to start and stop CRRT as well as describing potential treatment complications. This review will also discuss the role of therapeutic plasma exchange in critical care and novel extracorporeal therapies including blood purification in sepsis and carbon dioxide removal in acute respiratory distress syndrome and acute exacerbations of obstructive lung disease. Extracorporeal membrane oxygenation is outside of the scope of this article.

A systematic review of the literature assessing operative blood loss and postoperative outcomes after colorectal surgery.

PURPOSE: There is no consensus in the literature regarding the association between operative blood loss and postoperative outcomes in colorectal surgery, despite evidence suggesting a link. Therefore, this systematic review assesses the association between operative blood loss, perioperative and long-term outcomes after colorectal surgery. METHODS: A literature search of MEDLINE, EMBASE, Science Citation Index Expanded and Cochrane was performed to identify studies reporting on operative blood loss in colorectal surgery. RESULTS: The review included forty-nine studies reporting on 61,312 participants, with a mean age ranging from 53.4 to 78.1 years. The included studies demonstrated that major operative blood loss was found to be a risk factor for mortality, anastomotic leak, presacral abscess, and postoperative ileus, leading to an increased duration of hospital stay. In the long term, the studies suggest that significant blood loss was an independent risk factor for future small bowel obstruction due to colorectal cancer recurrence and adhesions. Studies found that survival was significantly reduced, whilst the risk of colorectal cancer recurrence was increased. Reoperation and cancer-specific survival were not associated with major blood loss. CONCLUSION: The results of this systematic review suggest that major operative blood loss increases the risk of perioperative adverse events and has short and long-term repercussions on postoperative outcomes. Laparoscopic and robotic surgery, vessel ligation technology and anaesthetic considerations are essential for reducing blood loss and improving outcomes. This review highlights the need for further high quality, prospective, multicentre trials with a greater number of participants, and accurate and standardised methods of measuring operative blood loss.

The effect of left ventricular longitudinal strain on left atrial function and ventricular filling in hypertension.

AIM: To assess the relationship of global longitudinal strain during left atrial (LA) and left ventricular (LV) filling and emptying. MATERIALS AND METHODS: Using magnetic resonance imaging in 47 hypertensive patients, biplane global LV longitudinal strain was evaluated and related to LA and LV filling and emptying (by volumetric analysis), and to pulmonary vein and trans-mitral flow (by phase-contrast imaging). The results were compared to normal subjects. RESULTS: In hypertensive patients, reduced global longitudinal LV strain was associated with reduced LA reservoir (47 ± 10 versus 53 ± 9%, p<0.05), reduced LA conduit function (21 ± 9 versus 32 ± 11%, p<0.004), reduced LA early peak emptying rate (150 ± 77 versus 230 ± 88 ml/s, p=0.007), and slower early LV filling (373 ± 141 versus 478 ± 141 ml/s, p=0.03). LA peak filling rate showed a positive correlation to LV peak emptying rate (R=0.331, p=0.02). CONCLUSION: In hypertensive heart disease, impaired LV longitudinal systolic function causes reduced LA filling and emptying, and this leads directly to impaired LV filling and diastolic dysfunction.

A systematic review and network meta-analysis comparing energy devices used in colorectal surgery.

BACKGROUND: The aim of this study was to compare energy devices used for intraoperative hemostasis during colorectal surgery. METHODS: A systematic literature review and Bayesian network meta-analysis performed. MEDLINE, EMBASE, Science Citation Index Expanded, and Cochrane were searched from inception to August 11th 2021. Intraoperative outcomes were operative blood loss, operative time, conversion to open, conversion to another energy source. Postoperative outcomes were mortality, overall complications, minor complications and major complications, wound complications, postoperative ileus, anastomotic leak, time to first defecation, day 1 and 3 drainage volume, duration of hospital stay. RESULTS: Seven randomized controlled trials (RCTs) were included, reporting on 680 participants, comparing conventional hemostasis, LigaSure™, Thunderbeat® and Harmonic®. Harmonic® had fewer overall complications compared to conventional hemostasis. Operative blood loss was less with LigaSure™ (mean difference [MD] = 24.1 ml; 95% confidence interval [CI] - 46.54 to - 1.58 ml) or Harmonic® (MD = 24.6 ml; 95% CI - 42.4 to - 6.7 ml) compared to conventional techniques. Conventional hemostasis ranked worst for operative blood loss with high probability (p = 0.98). LigaSure™, Harmonic® or Thunderbeat® resulted in a significantly shorter mean operative time by 42.8 min (95% CI - 53.9 to - 31.5 min), 28.3 min (95% CI - 33.6 to - 22.6 min) and 26.1 min (95% CI - 46 to - 6 min), respectively compared to conventional electrosurgery. LigaSure™ resulted in a significantly shorter mean operative time than Harmonic® by 14.5 min (95% CI 1.9-27 min) and ranked first for operative time with high probability (p = 0.97). LigaSure™ and Harmonic® resulted in a significantly shorter mean duration of hospital stay compared to conventional electrosurgery of 1.3 days (95% CI - 2.2 to - 0.4) and 0.5 days (95% CI - 1 to - 0.1), respectively. LigaSure™ ranked as best for hospital stay with high probability (p = 0.97). Conventional hemostasis was associated with more wound complications than Harmonic® (odds ratio [OR] = 0.27; CI 0.08-0.92). Harmonic® ranked best with highest probability (p = 0.99) for wound complications. No significant differences between energy devices were identified for the remaining outcomes. CONCLUSIONS: LigaSure™, Thunderbeat® and Harmonic® may be advantageous for reducing operative blood loss, operative time, overall complications, wound complications, and duration of hospital stay compared to conventional techniques. The energy devices result in comparable perioperative outcomes and no device is superior overall. However, included RCTs were limited in number and size, and data were not available to compare all energy devices for all outcomes of interest.

Systematic review and meta-analysis comparing perioperative outcomes of pediatric emergency appendicectomy performed by trainee vs trained surgeon.

Appendicectomy is a common pediatric surgical procedure performed by trainees and surgeons with varying reported outcomes. It is a benchmark procedure for trainee progression and training benefits should be weighed against patient safety and perioperative outcomes. This systematic review and meta-analysis investigated any differential perioperative outcomes dependent on the grade of the operating surgeon. A systematic literature review and meta-analysis were performed comparing outcomes of pediatric appendicectomy performed by trainees versus trained surgeons. Of 2,086 articles screened, 5 retrospective non-randomized comparative studies reporting on 10,019 participants were analyzed. There was no difference in overall complications (OR 0.92; 95% CI 0.76, 1.12; P = 0.42), major complications [Clavien-Dindo (CD) III/IV] (OR 1.18; 95% CI 0.71, 1.97; P = 0.52), minor complications (CD I/II) (OR 1.13; 95% CI 0.57, 2.27; P = 0.72), post-op ileus (OR 0.74; 95% CI 0.10, 5.26; P = 0.76), wound infections (OR 0.87; 95% CI 0.62, 1.21; P = 0.41), abscess formation (OR 0.58; 95% CI 0.28, 1.22; P = 0.15), operation times [Mean Difference (MD) 2.31 min; 95% CI - 4.94, 9.56; P = 0.53] and reoperation rate (OR 1.22; 95% CI 0.23, 6.42; P = 0.81). Trainees had fewer conversions to open appendicectomy (OR 0.14; 95% CI 0.02, 0.88; P = 0.04). Appendicectomy performed on pediatric patients by trainees did not compromise patient safety. LEVEL OF EVIDENCE: III.

Acute kidney injury following endovascular intervention for peripheral artery disease.

BACKGROUND: The incidence of, and risk factors for, acute kidney injury (AKI) after endovascular intervention for peripheral artery disease (PAD) remain unknown. The aim of this study was to assess the proportion of patients who develop AKI and explore the risk factors. METHODS: Prospectively collected data on patients undergoing femoropopliteal endovascular intervention for symptomatic PAD across three vascular centres were analysed. The proportion of patients developing AKI (according to the Kidney Disease Improving Global Outcomes definition) within 48 h, and the proportion developing the composite Major Adverse Kidney Events (MAKE) endpoints (death, dialysis, drop in estimated glomerular filtration rate at least 25 per cent) at 30 days (MAKE30) and remains 90 days (MAKE90) were calculated. Multivariable regression analysis was used to assess predictors of AKI, and the association between AKI and death. RESULTS: Some 2041 patients were included in the analysis. AKI developed in 239 patients (11.7 per cent), with 47 (2.3 per cent) requiring dialysis within 30 days, and 18 (0.9 per cent) requiring ongoing dialysis. The MAKE30 and MAKE90 composite endpoints were reached in 358 (17.5 per cent) and 449 (22.0 per cent) patients respectively. Risk factors for AKI were age, sex, congestive heart failure, chronic limb-threatening ischaemia, emergency procedure, and pre-existing chronic kidney disease. AKI, dementia, congestive heart failure, and major amputation were risk factors for medium-term mortality. CONCLUSION: AKI is a common complication after intervention for PAD and is associated with medium-term mortality.

A systematic review and meta-analysis of variants of the branches of the superior mesenteric artery: the Achilles heel of right hemicolectomy with complete mesocolic excision?

AIM: Dissection with subsequent ligation and resection of arteries at their origin (central vascular ligation) is essential for adequate oncological resection during right hemicolectomy with complete mesocolic excision. This technique is technically demanding due to the highly variable arterial pattern of the right colon. Therefore, this study aims to provide a comprehensive evidence-based assessment of the arterial vascular anatomy of the right colon. METHODS: A thorough systematic literature search through September 2020 was conducted on the electronic databases PubMed, Scopus and Web of Science to identify studies eligible for inclusion. Data were extracted and pooled into a meta-analysis using MetaXl software. RESULTS: A total of 41 studies (n = 4691 patients) were included. The ileocolic artery (ICA), right colic artery (RCA) and middle colic artery (MCA) were present in 99.7% (95% CI 99.4%-99.8%), 72.6% (95% CI 61.3%-82.5%) and 96.9% (95% CI 94.2%-98.8%) respectively of patients. Supernumerary RCA and MCA were observed in 3.2% and 11.4% respectively of all cases. The RCA shared a common trunk with the ICA and MCA in 13.2% and 17.7% respectively of patients. A retro-superior mesenteric vein course of the ICA and RCA was observed in 55.1% and 11.4% respectively of all cases. CONCLUSION: The vascular anatomy of the right colon displays several notable variations, namely the absence of some branches (RCA absent in 27.4% of cases), supernumerary branches, common trunks, and retro-superior mesenteric vein courses. These variations should be taken into consideration during right hemicolectomy with complete mesocolic excision to ensure adequate oncological resection while minimizing intra-operative complications.

Surgical anatomy of the accessory middle colic artery: a meta-analysis with implications for splenic flexure cancer surgery.

AIM: Surgical resection of splenic flexure cancers (SFCs) is technically demanding due to the complex regional anatomy, characterized by the presence of embryological adhesions, close proximity to the pancreas and spleen, and a highly heterogeneous arterial supply and lymphatic drainage. The accessory middle colic artery (AMCA) is increasingly being recognized as an important source of blood supply to the splenic flexure. The aim of this study is to determine the prevalence and anatomical features of the AMCA. METHOD: A systematic search of the scientific literature was conducted on PubMed and Embase from inception to November 2020 to identify potentially eligible studies. Data were extracted and prevalence was pooled into a meta-analysis using MetaXL and Meta-Analyst software. RESULTS: A total of 16 studies (n = 2203 patients) were included. The pooled prevalence (PP) of the AMCA was 25.4% (95% CI 18.1-33.4). Its prevalence was higher in patients without a left colic artery (LCA) (PP = 83.2%; 95% CI 70.4-93.1). The commonest origin for the AMCA was the superior mesenteric artery (PP = 87.9%; 95% CI 86.4-90.7). The AMCA shared a common trunk/gave rise to pancreatic branches in 23.1% of cases (95% CI 15.3-31.9). CONCLUSION: The AMCA contributes to the vascularization of the splenic flexure in approximately 25% of individuals, and may be an important feeder artery to SFCs, especially in the absence of a LCA. Preoperative identification of this artery is important to ensure optimal surgery for SFC and minimize complications.

Surgical anatomy of sigmoid arteries: A systematic review and meta-analysis.

BACKGROUND: The purpose of this systematic review and meta-analysis was to determine the prevalence of the number of sigmoid arteries (SA) and variations in their origins. METHODS: A thorough systematic search of literature through February 2020 was conducted on major electronic databases to identify eligible studies. Data were extracted and pooled into a meta-analysis using Metafor package in R. The primary outcome was the variations in the SA origin (according to modified Zebrowski classification), and the secondary outcome was the prevalence of the number of SA. RESULTS: A total of 22 studies (n = 2653 patients) were included. Type 1 modified Zebrowski (separated origins or common trunk of the SA originating from descending recto-sigmoid trunk (DRST)) was the most common origin type of the SA (pooled prevalence estimate (PPE) = 49.67% (95% CI 32. 67- 66.71)), while type 3 (separated origins or common trunk of 1 or 2 SA originating from DRST or superior rectal artery (SRA) and 1 or 2 SA originating from DRST or SRA) was the least common (PPE = 0.18%; 95% CI 0.00-2.82)). Of the Type 1 variants, the not specified (N.S) variant was by far the most prevalent. The number of SA ranged from one to five, with three being the mode (PPE = 42.3%). CONCLUSION: This is the most comprehensive analysis of arterial vascular anatomy of the sigmoid colon. In light of the highly variable anatomical pattern displayed by the SA, thorough pre-operative knowledge of their anatomy can be crucial in minimizing incidences of iatrogenic injury.

Right hemicolectomy with complete mesocolic excision is safe, leads to an increased lymph node yield and to increased survival: results of a systematic review and meta-analysis.

BACKGROUND: The introduction of complete mesocolic excision (CME) for right colon cancer has raised an important discussion in relation to the extent of colic and mesenteric resection, and the impact this may have on lymph node yield. As uncertainty remains regarding the usefulness of and indications for right hemicolectomy with CME and the benefits of CME compared with a traditional approach, the purpose of this meta-analysis is to compare the two procedures in terms of safety, lymph node yield and oncological outcome. METHODS: We performed a systematic review of the literature from 2009 up to March 15th, 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two hundred eighty-one publications were evaluated, and 17 met the inclusion criteria and were included. Primary endpoints analysed were anastomotic leak rate, blood loss, number of harvested lymph nodes, 3- and 5-year oncologic outcomes. Secondary outcomes were operating time, conversion, intraoperative complications, reoperation rate, overall and Clavien-Dindo grade 3-4 postoperative complications. RESULTS: In terms of safety, right hemicolectomy with CME is not inferior to the standard procedure when comparing rates of anastomotic leak (RR 0.82, 95% CI 0.38-1.79), blood loss (MD -32.48, 95% CI -98.54 to -33.58), overall postoperative complications (RR 0.82, 95% CI 0.67-1.00), Clavien-Dindo grade III-IV postoperative complications (RR 1.36, 95% CI 0.82-2.28) and reoperation rate (RR 0.65, 95% CI 0.26-1.75). Traditional surgery is associated with a shorter operating time (MD 16.43, 95% CI 4.27-28.60) and lower conversion from laparoscopic to open approach (RR 1.72, 95% CI 1.00-2.96). In terms of oncologic outcomes, right hemicolectomy with CME leads to a higher lymph node yield than traditional surgery (MD 7.05, 95% CI 4.06-10.04). Results of statistical analysis comparing 3-year overall survival and 5-year disease-free survival were better in the CME group, RR 0.42, 95% CI 0.27-0.66 and RR 0.36, 95% CI 0.17-0.56, respectively. CONCLUSIONS: Right hemicolectomy with CME is not inferior to traditional surgery in terms of safety and has a greater lymph node yield when compared with traditional surgery. Moreover, right-sided CME is associated with better overall and disease-free survival.