δ13C methane source signatures from tropical wetland and rice field emissions.

The atmospheric methane (CH4) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH4 emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new δ13CCH4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring of δ13CCH4 in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH4 sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH4 to the atmosphere during periods of reduced wetland extent. This new data expands the geographical extent and range of measurements of tropical wetland and rice δ13CCH4 sources and hints at significant seasonal variation in tropical wetland δ13CCH4 signatures which may be important to capture in future global and regional models. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.

Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights.

We report methane isotopologue data from aircraft and ground measurements in Africa and South America. Aircraft campaigns sampled strong methane fluxes over tropical papyrus wetlands in the Nile, Congo and Zambezi basins, herbaceous wetlands in Bolivian southern Amazonia, and over fires in African woodland, cropland and savannah grassland. Measured methane δ13CCH4 isotopic signatures were in the range -55 to -49‰ for emissions from equatorial Nile wetlands and agricultural areas, but widely -60 ± 1‰ from Upper Congo and Zambezi wetlands. Very similar δ13CCH4 signatures were measured over the Amazonian wetlands of NE Bolivia (around -59‰) and the overall δ13CCH4 signature from outer tropical wetlands in the southern Upper Congo and Upper Amazon drainage plotted together was -59 ± 2‰. These results were more negative than expected. For African cattle, δ13CCH4 values were around -60 to -50‰. Isotopic ratios in methane emitted by tropical fires depended on the C3 : C4 ratio of the biomass fuel. In smoke from tropical C3 dry forest fires in Senegal, δ13CCH4 values were around -28‰. By contrast, African C4 tropical grass fire δ13CCH4 values were -16 to -12‰. Methane from urban landfills in Zambia and Zimbabwe, which have frequent waste fires, had δ13CCH4 around -37 to -36‰. These new isotopic values help improve isotopic constraints on global methane budget models because atmospheric δ13CCH4 values predicted by global atmospheric models are highly sensitive to the δ13CCH4 isotopic signatures applied to tropical wetland emissions. Field and aircraft campaigns also observed widespread regional smoke pollution over Africa, in both the wet and dry seasons, and large urban pollution plumes. The work highlights the need to understand tropical greenhouse gas emissions in order to meet the goals of the UNFCCC Paris Agreement, and to help reduce air pollution over wide regions of Africa. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.

Outcomes of Late Microsurgical Nerve Reconstruction for Brachial Plexus Birth Injury.

PURPOSE: Microsurgical nerve reconstruction has been advocated between 3 and 9 months of life in select patients with brachial plexus birth injury (BPBI), yet some patients undergo indicated surgery after this time frame. Outcomes in these older patients remain poorly characterized. We analyzed outcomes of nerve reconstruction performed after 9 months of age and hypothesized that (1) Active Movement Scale (AMS) scores improve after surgery, and (2) there are no differences in AMS scores between patients undergoing nerve transfers versus those undergoing nerve grafting. METHODS: From 2000 to 2014, 750 patients at 6 U.S. centers were prospectively enrolled in a multicenter database. We included patients treated with nerve reconstruction after 9 months of age with minimum 12 months' follow-up. Patients were evaluated using AMS scores. To focus on the results of microsurgery, only outcomes prior to secondary surgery were analyzed. We analyzed baseline variables using bivariate statistics and change in AMS scores over time and across treatment groups using linear mixed models. RESULTS: We identified 32 patients (63% female) with median follow-up of 29.8 months. Median age at microsurgery was 11.2 months. Twenty-five (78%) had an upper trunk injury. Compared with before surgery, total AMS scores improved modestly at 1 year and 2 or more years follow-up. At 1 year follow-up, AMS scores improved for shoulder function (abduction, external rotation) and elbow flexion. Between-group comparisons found no differences in total AMS scores or AMS subscales between graft and transfer groups at 1 year or 2 or more years after surgery, so we cannot recommend one strategy over the other based on our findings. CONCLUSIONS: Overall, nerve reconstruction in patients with BPBI after 9 months of age resulted in improved function over time. There was no difference in outcomes between nerve transfer and nerve graft groups and 1 or 2 or more years follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Leech Therapy Following Digital Replantation and Revascularization.

Venous congestion after digital replantation or revascularization threatens digit survival in the immediate postoperative period. External bloodletting, including leech therapy, provides a central role in salvage of the congested finger. Although there have been previous studies describing the initiation of leech therapy for digits experiencing venous insufficiency, few published articles and no consensus guidelines have discussed the weaning of leeches in the postoperative period. We review the current evidence behind leech therapy and offer a treatment algorithm based on available data and existing leech weaning protocols.

The impact of meeting donor management goals on the number of organs transplanted per donor: results from the United Network for Organ Sharing Region 5 prospective donor management goals study.

OBJECTIVE: Many organ procurement organizations have implemented critical care end points as donor management goals in efforts to increase organs transplanted per donor after neurologic determination of death. Although retrospective studies have demonstrated an association between meeting donor management goals and organ yield, prospective studies are lacking. DESIGN: In June 2008, nine donor management goals were prospectively implemented as a checklist and every donor after neurologic determination of death was managed to meet them. The donor management goals represented normal cardiovascular, pulmonary, renal, and endocrine end points. Data were collected for 7 months. Donor management goals "met" was defined a priori as achieving any seven of the nine donor management goals, and this was recorded at the time of consent, 12-18 hrs later, and prior to organ recovery. The primary outcome measure was ≥4 organs transplanted per donor, and binary logistic regression was used to identify independent predictors of this outcome with a p<.05. SETTING: All eight organ procurement organizations in the five Southwestern United States (United Network for Organ Sharing Region 5). SUBJECTS: All standard criteria donors after neurologic determination of deaths. INTERVENTION: Prospective implementation of a donor management goal checklist. MEASUREMENTS AND MAIN RESULTS: There were 380 standard criteria donors with 3.6±1.7 organs transplanted per donor. Fifteen percent had donor management goals met at the time of consent, 33% at 12-18 hrs, and 38% prior to organ recovery. Forty-eight percent had ≥4 organs transplanted per donor. Donors with ≥4 organs transplanted per donor had significantly more individual donor management goals met at all three time points. Independent predictors of ≥4 organs transplanted per donor were age (odds ratio=0.95 per year), final creatinine (odds ratio=0.75 per 1-unit increase), donor management goals "met" at consent (odds ratio=2.03), donor management goals "met" prior to organ recovery (odds ratio=2.34), and a change in the number of donor management goals achieved from consent to 12-18 hrs later (odds ratio=1.13 per additional donor management goal). CONCLUSIONS: Meeting donor management goals prior to consent and prior to organ recovery were both associated with achieving ≥4 organs transplanted per donor. However, only 15% of donors have donor management goals met at the time of consent. The donor hospital management of patients with catastrophic brain injuries, before the intent to donate organs is known, affects outcomes and should remain a priority in the intensive care unit.

Achieving donor management goals before deceased donor procurement is associated with more organs transplanted per donor.

BACKGROUND: There is a national shortage of organs available for transplantation. Implementation of preset donor management goals (DMGs) to improve outcomes is recommended, but uniform practices and data are lacking. We hypothesized that meeting DMGs before organ procurement would result in more organs transplanted per donor (OTPD). METHODS: The eight organ procurement organization in United Network for Organ Sharing Region 5 selected 10 critical care end points as DMGs. Each organ procurement organization submitted retrospective data from 40 standard criteria donors. "DMGs met" was defined as achieving any eight DMGs before procurement. The primary outcome was ≥4 OTPD. Binary logistic regression was used to determine independent predictors of ≥4 OTPD with a p<0.05. RESULTS: Three hundred twenty standard criteria donors had 3.6±1.6 OTPD. Donors with DMGs met had more OTPD (4.4 vs. 3.3, p<0.001) and were more likely to have ≥4 OTPD (70% vs. 39%, p<0.001). Independent predictors of ≥4 OTPD were age (odds ratio [OR]=0.94), serum creatinine (OR=0.65), thyroid hormone use (OR=2.0), "DMGs met" (OR=4.4), and achieving the following individual DMGs: central venous pressure 4 mm Hg to 10 mm Hg (OR=1.9), ejection fraction>50% (OR=4.0), Pao2:FIO2>300 (OR=4.6), and serum sodium 135 to 160 mEq/L (OR=3.4). CONCLUSIONS: Meeting DMGs before procurement resulted in more OTPD. Donor factors and critical care end points are independent predictors of organ yield. Prospective studies are needed to determine the true impact of each DMG on the number and function of transplanted organs.

Dorsal Cortical Breaks in Volar Barton Distal Radius Fractures.

Background: Volar Barton fractures involve the volar articular margin of the distal radius with proximal and volar subluxation of the carpus. Although traditionally conceptualized as partial articular, some volar Barton fractures are complete articular injuries due to a dorsal cortical break in the distal radial metaphysis. While dorsal cortical breaks can affect surgical strategy, they may be difficult to identify on plain radiographs and their epidemiology remains poorly characterized. Some authors have hypothesized an association with osteoporosis; however, this hypothesis remains untested. To better characterize volar Barton fractures, we analyzed fracture geometry on pre-operative computed tomography (CT) scans to: (1) determine the frequency of a dorsal cortical break; and (2) test the null hypothesis that a dorsal cortical break is not associated with age or gender. Methods: We retrospectively reviewed adults with a volar Barton distal radius fracture and an available pre-operative CT who underwent surgical fixation. Using multivariable logistic regression, we assessed whether age or gender was an independent predictor of a dorsal cortical break. Results: Forty patients (mean age 52 years, 57% female) were identified. Including the shaft as a fragment, 32 (80%) had 3 or more discrete fracture fragments. Thirty patients (75%) had a dorsal cortical break. Dorsal cortical breaks were not associated with either age or gender (P > 0.05). Conclusions: Most (75%) patients with volar Barton distal radius fractures had a dorsal cortical break. Dorsal cortical breaks were not statistically associated with age or gender, suggesting these fracture patterns may not be associated with osteoporosis as previously hypothesized.

Hyperbaric oxygen therapy as an adjunctive treatment for diabetic foot wounds: a comprehensive review with case studies.

 Complications associated with diabetes are often expensive to treat, and commonly include foot ulceration. While most diabetic foot ulcers heal with standard treatment, when standard treatment measures fail, adjunctive therapies must be considered. We review the theory and evidence for the use of systemic Hyperbaric Oxygen Therapy (HBOT) as an adjunctive treatment for chronic lower extremity diabetic ulceration. Two clinical cases of patients treated with HBOT for refractory diabetic foot ulceration at Georgetown University Hospital are presented. A growing body of evidence suggests that oxygen plays a major role in whether wounds heal normally or remain nonhealing chronic wounds. An oxygen gradient, from high oxygen levels in the edges of the wound to hypoxic conditions in the wound center, seems to optimally stimulate wound healing. Wounds that are instead surrounded by hypoxic tissue lack this oxygen gradient and seem less likely to heal. In wounds with adequate perfusion, HBOT may overcome periwound hypoxia to create an oxygen gradient and stimulate healing of otherwise nonhealing wounds. The clinical trials assessing the effectiveness of HBOT in diabetic wound healing have been inconclusive. However, considering the evidence supporting oxygen's role in wound healing and the potential for HBOT to decrease medical costs related to the care of chronic diabetic ulcers, there is a need for more extensive clinical trials to evaluate HBOT efficacy.

Chronic Scapholunate Interosseous Ligament Disruption: A Systematic Review and Meta-Analysis of Surgical Treatments.

Background: Although many techniques have been described, there is no clear optimal surgical treatment for chronic scapholunate interosseous ligament (SLIL) disruption. Methods: We identified 255 articles reporting outcomes of SLIL reconstruction. Of these, 40 studies (978 wrists) met eligibility requirements and reported sufficient data on radiographic outcomes to be included in the study. The mean and standard deviation of preoperative and follow-up assessments including scapholunate gap (SLG) and scapholunate angle (SLA) were used to calculate pooled standardized mean differences (SMD) with 95% confidence intervals (CIs). For other radiographic or clinical outcomes, there were not enough reported data to calculate a pooled effect size, and pooled nonstandardized comparisons were made. Results: The SMD between preoperative and postoperative SLA in tenodesis reconstruction was 0.7 (CI, 0.29 to 1.11, P = .001) and 0.04 (CI, -0.27 to 0.38, P = .8) for capsulodesis reconstruction. For SLG, tenodesis demonstrated an SMD of 1.1 (CI, 0.6 to 1.55, P < .001) compared with 0.1 (CI, -0.36 to 0.59, P = .6) for capsulodesis reconstruction. Tenodesis had a significant improvement compared with capsulodesis in SLA (P = .01) and SLG (P = .005). Tenodesis also showed improvement in grip strength and Disabilities of the Arm, Shoulder and Hand scores. Conclusions: Comparing preoperative and postoperative radiographic measurements, tenodesis reconstruction demonstrated significantly improved SLG and SLA relative to capsulodesis. Interpreted in the context of the limitations, existing data demonstrates some benefit of tenodesis reconstruction.

A Single Incision Anterior Approach for Transhumeral Amputation Targeted Muscle Reinnervation.

Targeted muscle reinnervation (TMR) is an evolving technique with promising results for prevention and treatment of neuropathic pain, as well as modulation of control for myoelectric prostheses. The previously described and most commonly used technique for transhumeral TMR combines both an anterior and posterior approach to access the major peripheral nerves of the upper extremity. In this article, we review the literature for transhumeral TMR and describe a more expeditious and efficient anterior-only approach that offers safe access through a single incision.

The Influence of Insurance Status on the Surgical Treatment of Acute Spinal Fractures.

STUDY DESIGN: A retrospective, propensity score, multivariate analysis of the National Trauma Data Bank (NTDB) between 2008 and 2011. OBJECTIVE: The aim of this study was to determine the relationship between insurance status and rates of surgery for acute spinal fractures with and without spinal cord injury (SCI). SUMMARY OF BACKGROUND DATA: The decision for surgery in patients with spinal fractures is often based on fracture pattern and stability, associated SCI, and the presence of ligamentous and other associated injuries. It is poorly understood how nonclinical factors, such as insurance status, influence the decision for surgical intervention in patients sustaining spinal trauma. METHODS: Using NTDB admission years 2008 to 2011, we included patients 18 to 64 years old who sustained a fracture of the cervical or thoracolumbar spine. Patients were excluded if they sustained polytrauma (Injury Severity Score ≥27) or a major injury (Abbreviated Injury Scale severity ≥3) to the head, thorax, or abdomen. Our main outcome measure was surgical versus nonsurgical treatment for spinal injury; our main predictor was insurance status. Hierarchical multivariate regression analysis and propensity scores were used to determine the relationship between insurance status and surgical treatment, controlling for other factors. We calculated adjusted odds ratios (ORs) for rates of surgery. RESULTS: Our propensity score multivariate analysis demonstrated significantly higher rates of surgery in patients with SCI (OR = 11.76, P < 0.001), insurance (OR = 1.27, P < 0.001), white (OR = 1.21, P = 0.018) versus black race, blunt trauma (OR = 5.63, P < 0.001), shock (OR = 1.62, P < 0.001), higher Glasgow Coma Scale (GCS) score (OR = 1.02, P = 0.002), transfer from lower acuity hospital (OR = 1.51, P < 0.001), and treatment at teaching hospitals (OR = 1.49, P < 0.001). Multivariable subgroup analysis of SCI patients similarly revealed higher surgical rates for insured patients (OR = 1.46, P < 0.001) than those without insurance. CONCLUSION: Patients with traumatic spine fractures were more likely to receive surgery if they were insured, regardless of the presence of SCI.

A 20-year analysis of hand and wrist research productivity in Asia.

Bibliometric analyses of the hand and wrist research have previously shown a significant increase in research productivity in Asia. We examined the key contributors to this change by performing bibliometric analyses regarding hand and wrist research in all Asian countries producing significant research. Original research articles from 1988 to 2007 were collected from seven English language journals based on the impact factor. Trends in research productivity were determined by country using linear regression analysis. Compared to the rest of the world, Asia produced fewer level I and basic studies, but more level IV studies. Significant increase in both research volume and productivity in Asia was observed, with Japan, Korea, and Taiwan having the highest aggregate productivity in hand and wrist research. From 1988 to 2007, the relative research production among Asian countries showed significant change, in contrary to that of Europe, Latin American, and the United States.