Pyrocumulonimbus affect average stratospheric aerosol composition.

Pyrocumulonimbus (pyroCb) are wildfire-generated convective clouds that can inject smoke directly into the stratosphere. PyroCb have been tracked for years, yet their apparent rarity and episodic nature lead to highly uncertain climate impacts. In situ measurements of pyroCb smoke reveal its distinctive and exceptionally stable aerosol properties and define the long-term influence of pyroCb activity on the stratospheric aerosol budget. Analysis of 13 years of airborne observations shows that pyroCb are responsible for 10 to 25% of the black carbon and organic aerosols in the "present-day" lower stratosphere, with similar impacts in both the North and South Hemispheres. These results suggest that, should pyroCb increase in frequency and/or magnitude in future climates, they could generate dominant trends in stratospheric aerosol.

Management of oral and maxillofacial trauma during the first wave of the COVID-19 pandemic in the United Kingdom.

We assess the effect of coronavirus disease 2019 (COVID-19) on UK oral and maxillofacial (OMF) trauma services and patient treatment during the first wave of the pandemic. From 1 April 2020 until 31 July 2020, OMF surgery units in the UK were invited to prospectively record all patients presenting with OMF trauma. Information included clinical presentation, mechanism of injury, how it was managed, and whether or not treatment included surgery. Participants were also asked to compare the patient's care with the treatment that would normally have been given before the crisis. Twenty-nine units across the UK contributed with 2,229 entries. The most common aetiology was mechanical fall (39%). The most common injuries were soft tissue wounds (52%) and, for hard tissues, mandibular fractures (13%). Of 876 facial fractures, 79 patients' treatment differed from what would have been normal pre-COVID, and 33 had their treatment deferred. Therefore the care of 112 (14%) patients was at variance with normal practice because of COVID restrictions. The pattern of OMFS injuries changed during the first COVID-19 lockdown. For the majority, best practice and delivery of quality trauma care continued despite the on-going operational challenges, and only a small proportion of patients had changes to their treatment. The lessons learnt from the first wave, combined with adequate resources and preoperative testing of patients, should allow those facial injuries in the second wave to receive best-practice care.

Printed titanium implants in UK craniomaxillofacial surgery. Part II: perceived performance (outcomes, logistics, and costs).

This second part explores perceptions and understanding of clinical performance, turnaround, and costs for printed titanium implants or plates in common procedures, evaluating both 'in-house' and 'outsourced' CAD-CAM pathways. A cross-sectional study, supported by the British Association of Oral and Maxillofacial Surgeons (BAOMS) and a national trainee-led recruitment team, was conducted over 14 weeks. A total of 132 participants took part (demographic data is reported in Part I). For fibular-flap mandibular reconstruction, most participants (69% - 91%) perceived printed titanium as superior to intraoperatively or preoperatively hand-bent plates for surgical duration, accuracy, dental restorability, and aesthetics. There was less agreement about complications and plate-failure risks. Most perceived printed plates to be superior to traditional wafer-based maxillary osteotomy for surgical duration (61%) and maxillary positioning (60%). For orbital floor repair, most perceived improvements in surgical duration (83%, especially higher-volume operators p=0.009), precision (84%), and ease of placement (69%). Rarely (less than 5%) was any outcome rated inferior to traditional techniques for any procedure. Perceived turnaround times and costs were variable, but the greatest consensus was for two-segment fibular-flap reconstructions and orbital floor repair. Industry estimates were generally consistent between two company representatives, but manufacturing-only costs differed when using in-house (departmental) designers. Costs and turnaround times are questionable barriers since few understand 'real-world' figures. Designing in-house can dramatically alter costs. Improved accuracy and surgical duration are common themes but biomechanical benefits are less-well understood. This study paints a picture of the potentially routine applications and benefits of printed titanium, capacity for uptake, understanding amongst surgeons, and areas for improvement.

Printed titanium implants in UK craniomaxillofacial surgery. Part I: access to digital planning and perceived scope for use in common procedures.

This first part of a two-part study examines perceived applications for and barriers to using printed titanium in light of current caseloads, funding pathways, and use of digital planning. It aims to demonstrate the scope for printed titanium in modern practice and to guide industry about the needs of UK surgeons. A cross-sectional study over 14 weeks was performed electronically with support from the British Association of Oral and Maxillofacial Surgeons (BAOMS) and a national trainee-led recruitment team. Ethics approval was obtained at the lead centre. A total of 132 participants joined the study (70% consultants, 25% specialty registrars, and 5% other), approximating a 29% response rate from consultant/registrar BAOMS members throughout mainland UK. Eighty-eight per cent used CAD-CAM design, with highly variable funding/access, design/manufacturing workflows (in-house/outsourced). Eighty-eight per cent were involved with trauma, 61% with orthognathic, and 52% with oncology-reconstruction surgery. Favourite applications for printed titanium were orbital floor repair (89%) and free-flap jaw reconstruction (87%). Most participants also cited maxillary/zygomatic osteotomies and cranioplasty (range 61%-73%). Although a popular application (78%), the evidence base in temporomandibular joint surgery is limited. Those performing orthognathic surgery perceived more indications than those who did not (p=0.013). Key barriers included cost, turnaround time and logistics, and the need to be trained in traditional techniques. Printed titanium was useful for both common and niche procedures, but was specifically limited in emergency trauma. Most surgeons had experience in CAD-CAM surgery but technical understanding appeared unclear. Limiting factors included variable funding and production pathways, perceived costs, and logistics, but in-house design can minimise them. In part II, we quantify perceived benefits and limitations and whether surgeons' understanding and knowledge are sufficient to rationalise them.

Association between early weight gain and later adiposity in Sri Lankan adolescents.

Early growth pattern is increasingly recognized as a determinant of later obesity. This study aimed to identify the association between weight gain in early life and anthropometry, adiposity, leptin, and fasting insulin levels in adolescence. A cross-sectional study was conducted in 366 school children aged 11-13 years. Weight, height, and waist circumference (WC) were measured. Fat mass (FM) was assessed using bioelectrical impedance analysis. Blood was drawn after a 12-h fast for insulin and leptin assay. Birth weight and weight at 6 months and at 18 months were extracted from Child Health Development Records. An increase in weight SD score (SDS) by ≥0.67 was defined as accelerated weight gain. Linear mixed-effects modeling was used to predict anthropometry, adiposity, and metabolic outcomes using sex, pubertal status, accelerated weight gain as fixed factors; age, birth weight, and family income as fixed covariates, and school as a random factor. Children with accelerated weight gain between birth and 18 months had significantly higher body mass index (BMI) SDS, WC SDS, height SDS, %FM, fat mass index (FMI), fat free mass index (FFMI), and serum leptin levels in adolescence. Accelerated weight gain between 6 and 18 months was associated with higher BMI SDS, WC SDS, %FM, and FMI, but not with height SDS or FFMI. Accelerated weight gain at 0-6 months, in children with low birth weight, was associated with higher height SDS, BMI SDS, WC SDS, %FM, and FMI; in children with normal birth weight, it was associated with BMI SDS, WC SDS, height SDS, and FFMI, but not with %FM or FMI. Effects of accelerated weight gain in early life on anthropometry and adiposity in adolescence varied in different growth windows. Accelerated weight gain during 6-18 months was associated with higher FM rather than linear growth. Effects of accelerated weight gain between 0 and 6 months varied with birth weight.

Immediate compared with late repair of extracranial branches of the facial nerve: a comparative study.

The best outcomes after injury to the facial nerve are seen after immediate direct coaptation, but in practice, this happens infrequently. We ask whether late repair (between 3 weeks and 18 months) is comparable to immediate repair. In this prospective observational study over a two-year period (2016-18), we identified 18 patients (11 male and 7 female, mean (range) age 58 (23-94) years), who had sustained extracranial injuries to the facial nerve. Eight were identified in the acute phase (within 72hours of injury) and repaired (immediate repair group). Ten presented in the late phase beyond six months (late repair group), and had direct coaptation, neurolysis, nerve transfer, or non-vascularised or vascularised nerve grafts. Patients were followed up clinically with photographic or video analysis every three months using the Sunnybrook facial grading scale and Terzis scores as quantitative tools. In the immediate repair group six patients had direct nerve coaptations, one had a free vascularised nerve graft, and one a fascicular nerve flap. In the late repair group six patients had coaptations, two had nerve transfers, one had neurolysis, and one nerve transfer and a free vascularised nerve graft. The null hypothesis that there was no difference between immediate and late repair of the facial nerve in terms of clinical improvement was accepted. The overall facial grading scale between the two groups showed no significant difference (mean 97 compared with 87; 95% CI: -25.61 to 5.32; p=0.18). However, the individual volitional facial grading score for the affected division showed that immediate repair fared significantly better than late repair (mean 4.55 compared with 3.14; 95% CI: -2.5 to -0.3; p=0.027). Supermicrosurgical techniques, together with advanced systems for nerve identification allow for coaptation of the maximum number of injured nerve branches. These factors accounted for a 97% mean return of function after immediate repair and an 87% recovery in the late repair group. While quantitatively, immediate repair is best, the re-establishment of nerve-muscle continuity before degeneration of the motor endplate confers the best possible physiological outcome, and is far superior to any of the techniques used to treat chronic facial paralysis.

Experimental platform to facilitate novel back brace development for the improvement of spine stability.

The spine or 'back' has many functions including supporting our body frame whilst facilitating movement, protecting the spinal cord and nerves and acting as a shock absorber. In certain instances, individuals may develop conditions that not only cause back pain but also may require additional support for the spine. Common movements such as twisting, standing and bending motions could exacerbate these conditions and intensify this pain. Back braces can be used in certain instances to constrain such motion as part of an individual's therapy and have existed as both medical and retail products for a number of decades. Arguably, back brace designs have lacked the innovation expected in this time. Existing designs are often found to be heavy, overly rigid, indiscrete and largely uncomfortable. In order to facilitate the development of new designs of back braces capable of being optimised to constrain particular motions for specific therapies, a numerical and experimental design strategy has been devised, tested and proven for the first time. The strategy makes use of an experimental test rig in conjunction with finite element analysis simulations to investigate and quantify the effects of back braces on flexion, extension, lateral bending and torsional motions as experienced by the human trunk. This paper describes this strategy and demonstrates its effectiveness through the proposal and comparison of two novel back brace designs.

Validating a risk stratification tool for audit of early outcome after operations for squamous cell carcinoma of the head and neck.

The aim of this study was to validate a case-mix adjustment tool (neural network) for the audit of postoperative outcomes. We tested its calibration and discrimination on two unseen groups of patients being treated for squamous cell carcinoma (SCC) of the head and neck and compared observed complication rates with predicted rates. A total of 196 patients who were treated at two UK NHS institutions between 2016 and 2018 were audited. Preoperative data pertaining to risk (T classification, complexity of operation, and "high-risk" status) were collected, together with data on postoperative complications. Diagnostic test statistics and receiver operating curves (ROC) were used to test the performance of the tool. The score was well calibrated (predicted and observed complication rates both 43%), but discrimination suggested only fair accuracy (ROC 0.66 - 0.68). Adjustment of case mix for the audit of postoperative complications is difficult, although our model suggests that departmental audit is possible, and its accuracy is equivalent to that of other national audits. Further work may elucidate key variables that have not yet been assessed.

Case-mix adjustment in audit of length of hospital stay in patients operated on for cancer of the head and neck.

Patients treated surgically for squamous cell carcinoma (SCC) of the head and neck form a heterogeneous group, and it is difficult to take this variation into account when measuring the quality of care. We have tested the feasibility of mathematical models that allow for the adjustment for case mix when auditing the length of hospital stay as a proxy indicator of the quality of care. We completed a case-note audit of 733 surgical episodes of care for SCC of the head and neck in five cancer networks, and used logistic regression and decision tree analysis to adjust for case mix using pertinent preoperative variables. Risk adjustment models of length of stay included age, alcohol, T classification, performance status, tracheostomy, high-risk status, and complexity of operation. The risk-adjusted length of stay differed significantly between the cancer networks studied (p<0.001). The models performed acceptably for the purpose of audit when this was under 15 days. Length of stay is a measurable outcome that can be used as a benchmark of surgical care. Audits of this after operations for cancer of the head and neck, if reported in national clinical audits, should take case mix into account.

Audit of minimally-invasive surgery for submandibular sialolithiasis.

Sialolithiasis is one of most common diseases to affect major salivary glands, with a symptomatic incidence of 27 cases per million per annum. The majority form within the submandibular gland where minimally-invasive treatments have all but eliminated adenectomy. All records of patients presenting with submandibular stones between 1997 and 2015 were reviewed. Stones <5mm were retrieved through endoscopic or radiographic techniques, 5-7mm stones were initially considered for extra-corporeal shock wave lithotripsy, but after poor results were treated through intraoral surgical removal with those >7mm. Follow up was performed at 1 week and 3 months with current status performed with postal and telephone questionnaires. 378 patients had 424 stones removed, successful retrieval in 94% (n=356), with 50 having had previous failures. Median number of stones per patient was 1 (range 1-4), with a mean size of 8.6mm (SD 4.5mm) mainly located at the hilum (50.5%), anterior duct (30%) and Genu (17%). 256 patients (65%) treated through intraoral surgical extraction, 92 (24%) endoscopic alone. Inpatient stay was 1.4 days in first third and 0.5 days in final third. Adenectomy occurred in 14 patients, due to failure to retrieve the sialolith or unresolved symptoms. Complications involved 11 patients with permanent paraesthesia, 7 ranulas and 14 strictures. Patients with preoperative strictures were more likely to develop complications (p=0.002) with paraesthesia being most common. Intraoral minimally-invasive surgery is aesthetic, curative and spares the risk to marginal mandibular nerve and submandibular gland. Length of inpatient stay improved and ranula risk reduced throughout the study.

Fragments of drains retained during operations on the temporomandibular joint.

Drains are robust and reports of breakages and retained fragments are rare. There is no consensus about the management of such cases and we know of no reported cases. We present the case of an 18-year-old man with a retained drain fragment after repair of an open condyle.

Seldinger technique in repair of the parotid duct.

Injuries to the parotid ducts are difficult to locate, assess, and repair, and traditionally, solid metal dilators and soft plastic tubes have had only limited success. We describe the Seldinger technique with a central venous catheter, which makes repair easier.

How much exercise should be promoted to raise total daily energy expenditure and improve health?

Despite longstanding recognition of the benefits of a physically active lifestyle, there remains ambiguity regarding exactly how much exercise should be promoted to raise total energy expenditure (TEE) and improve health. This review provides a brief summary of the dose-response relationship between physical activity and relative risk of morbidity and mortality; mechanisms through which exercise drives an increase in TEE; the highest reported levels of TEE measured via doubly labelled water; and the potential impact of non-compliance and confounders in moderating the contribution of exercise to increase TEE. Cohort studies provide a compelling argument that 'more is better' regarding the exercise dose for increasing TEE, that increasing TEE is protective for health, and that this is mediated through increased cardiorespiratory fitness. However, growing evidence shows that ever increasing volumes of weekly physical activity may reverse the cost-benefit seen with more modest doses. Animal and human studies show that the elevation in TEE associated with increasing exercise volume is commonly less than expected, due to physiological confounders. Further, there is considerable evidence of behavioural non-compliance to planned exercise in all but the most highly motivated athletes. Therefore, inbuilt defence mechanisms may safeguard against TEE being elevated to maximum levels.

Rationale for novel intermittent dieting strategies to attenuate adaptive responses to energy restriction.

Eating patterns involving intermittent energy restriction (IER) include 'intermittent fasting' where energy intake is severely restricted for several 'fasting' days per week, with 'refeeding' days (involving greater energy intake than during fasting days) at other times. Intermittent fasting does not improve weight loss compared to continuous energy restriction (CER), where energy intake is restricted every day. We hypothesize that weight loss from IER could be improved if refeeding phases involved restoration of energy balance (i.e. not ongoing energy restriction, as during intermittent fasting). There is some evidence in adults with overweight or obesity showing that maintenance of a lower weight may attenuate (completely or partially) some of the adaptive responses to energy restriction that oppose ongoing weight loss. Other studies show some adaptive responses persist unabated for years after weight loss. Only five randomized controlled trials in adults with overweight or obesity have compared CER with IER interventions that achieved energy balance (or absence of energy restriction) during refeeding phases. Two reported greater weight loss than CER, whereas three reported similar weight loss between interventions. While inconclusive, it is possible that achieving energy balance (i.e. avoiding energy restriction or energy excess) during refeeding phases may be important in realizing the potential of IER.

Study protocol: a randomised controlled trial of supervised resistance training versus aerobic training in Sri Lankan adults with type 2 diabetes mellitus: SL-DART study.

BACKGROUND: The prevalence of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD) is rising globally. T2DM is particularly problematic in South Asia with an estimated 10-15% of Sri Lankans diagnosed with the disease. Exercise is known to improve blood glucose, lipid profiles, blood pressure and adiposity, key goals in the management of T2DM. However, much of the evidence to date has been gained from white Caucasians who have a different body composition and disease profile compared to South Asians. Similarly, the recreational exercise culture is new to Sri Lankans and the effects of exercise on T2DM has not been studied in this population. METHODS: The Sri Lanka Diabetes Aerobic and Resistance Training (SL-DART) Study will be comprised of 2 components. Component 1 is a 12-week randomized controlled trial (RCT) to compare the effects of a supervised progressive resistance exercise program (RT) and aerobic exercise program (AT) with standard treatment/control (CN). Sedentary Sri Lankan adults with T2DM (aged 35-65 years) and with no contraindications to exercise will be randomized into one of 3 groups (AT, RT, CN). Exercise sessions will be conducted 2 days/week for 3 months. Baseline and post-intervention biochemical (glycemic control, lipid and liver profiles, inflammatory markers), anthropometric (height, weight, body circumferences), body composition, physical fitness, food preference (liking and wanting food) and quality of life parameters will be measured and compared between groups. Component 2 will be a qualitative study conducted immediately post-intervention via in-depth interviews to assess the barriers and facilitators for adherence to each exercise program. DISCUSSION: SL-DART Study represents one of the first adequately powered methodologically sound RCTs conducted in South Asia to assess the effects of resistance and aerobic exercise in participants with T2DM. Triangulation of quantitative and qualitative outcomes will enable the design of a culturally appropriate therapeutic physical activity intervention for Sri Lankans with T2DM, and the initiation of a professionally driven and specialized clinical exercise prescription service. TRIAL REGISTRATION: Sri Lanka Clinical Trials Registry; SLCTR/2016/017 . Date registered 17.06.2016. Universal trial number U1111-1181-7561.

Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study.

BACKGROUND/OBJECTIVES: The MATADOR (Minimising Adaptive Thermogenesis And Deactivating Obesity Rebound) study examined whether intermittent energy restriction (ER) improved weight loss efficiency compared with continuous ER and, if so, whether intermittent ER attenuated compensatory responses associated with ER. SUBJECTS/METHODS: Fifty-one men with obesity were randomised to 16 weeks of either: (1) continuous (CON), or (2) intermittent (INT) ER completed as 8 × 2-week blocks of ER alternating with 7 × 2-week blocks of energy balance (30 weeks total). Forty-seven participants completed a 4-week baseline phase and commenced the intervention (CON: N=23, 39.4±6.8 years, 111.1±9.1 kg, 34.3±3.0 kg m-2; INT: N=24, 39.8±9.5 years, 110.2±13.8 kg, 34.1±4.0 kg m-2). During ER, energy intake was equivalent to 67% of weight maintenance requirements in both groups. Body weight, fat mass (FM), fat-free mass (FFM) and resting energy expenditure (REE) were measured throughout the study. RESULTS: For the N=19 CON and N=17 INT who completed the intervention per protocol, weight loss was greater for INT (14.1±5.6 vs 9.1±2.9 kg; P<0.001). INT had greater FM loss (12.3±4.8 vs 8.0±4.2 kg; P<0.01), but FFM loss was similar (INT: 1.8±1.6 vs CON: 1.2±2.5 kg; P=0.4). Mean weight change during the 7 × 2-week INT energy balance blocks was minimal (0.0±0.3 kg). While reduction in absolute REE did not differ between groups (INT: -502±481 vs CON: -624±557 kJ d-1; P=0.5), after adjusting for changes in body composition, it was significantly lower in INT (INT: -360±502 vs CON: -749±498 kJ d-1; P<0.05). CONCLUSIONS: Greater weight and fat loss was achieved with intermittent ER. Interrupting ER with energy balance 'rest periods' may reduce compensatory metabolic responses and, in turn, improve weight loss efficiency.

Is parity a risk factor for excessive weight gain during pregnancy and postpartum weight retention? A systematic review and meta-analysis.

The aim of this study was to systematically review and meta-analyse the associations between parity, pre-pregnancy body mass index (BMI), gestational weight gain (GWG) and, when included, postpartum weight retention (PPWR). Papers reporting associations between parity and BMI and/or GWG in adult women were eligible: 2,195 papers were identified, and 41 longitudinal studies were included in the narrative synthesis; 17 studies were included in a meta-analysis. Findings indicated that parity was associated positively with pre-pregnancy BMI. In contrast, the role of parity in GWG was less clear; both positive and negative relationships were reported across studies. Parity was not associated directly with PPWR. This pattern of results was supported by our meta-analysis with the only significant association between parity and pre-pregnancy BMI. Overall, parity was associated with higher pre-pregnancy BMI; however, the role of parity in GWG and PPWR remains unclear, and it is likely that its influence is indirect and complex. Further research to better understand the contribution of parity to maternal obesity is warranted.

Sialendoscopy-assisted transfacial removal of parotid calculi.

Superficial parotidectomy has significant morbidity, and minimally invasive techniques have therefore been developed, including those involving sialendoscopy, to remove sialoliths and preserve the gland along with its function. The size, mobility and location of the sialolith, alongside the presence of strictures, all dictate management. We outline basic treatment paradigms and describe two sialoendoscopyassisted surgical procedures developed for treating stones, one intraoral and one extraoral.