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To compare billing practices, reimbursement rates, and patient populations of otolaryngology (ORL) physicians practicing in rural and urban settings.Retrospective cross-sectional study.Medicare Provider Utilization and Payment Data: Physician and Other Supplier Data.Medicare-allowed payments, number of services, and number of patients were gathered along with patient population comorbidity statistics, including average hierarchical condition category risk scores.In 2019, 92% of the overall total 8959 ORL physicians practiced in an urban setting. These 8243 urban ORL physicians, on average, billed for 51 (interquartile range [IQR], 31-67) unique Healthcare Common Procedure Coding System (HCPCS) codes, cared for 393 (IQR, 172-535) Medicare patients, performed 1761 (IQR, 502-2070) services, and collected $139,957 (IQR, $55,527-$178,479) per provider. In contrast, the 704 rural ORL physicians, on average, billed for a greater number of unique HCPCS codes (59; IQR, 37-77;Most ORL physicians practice in large urban settings, a finding potentially related to financial sustainability and career opportunity. With an already small workforce, the aging rural ORL physician population is an identifiable weak point in the otolaryngology specialty that must be addressed with geo-specific recruitment campaigns, rural work incentivization, and the development of career advancement opportunities in rural areas.

Two commercially available porous coatings, Gription and Porocoat, were compared for the first time in a challenging intra-articular, weight-bearing, ovine model. Gription has evolved from Porocoat and has higher porosity, coefficient of friction, and microtextured topography, which are expected to enhance bone ingrowth. Cylindrical implants were press-fit into the weight-bearing regions of ovine femoral condyles and bone ingrowth and fixation strength evaluated 4, 8, and 16 weeks postoperatively. Biomechanical push-out tests were performed on lateral femoral condyles (LFCs) to evaluate the strength of the bone-implant interface. Bone ingrowth was assessed in medial femoral condyles (MFCs) as well as implants retrieved from LFCs following biomechanical testing using backscattered electron microscopy and histology. By 16 weeks, Gription-coated implants exhibited higher force (2455 ± 1362 vs. 1002 ± 1466 N; p = 0.046) and stress (12.60 ± 6.99 vs. 5.14 ± 7.53 MPa; p = 0.046) at failure, and trended towards higher stiffness (11,510 ± 7645 vs. 5010 ± 8374 N/mm; p = 0.061) and modulus of elasticity (591 ± 392 vs. 256 ± 431 MPa; p = 0.061). A strong, positive correlation was detected between bone ingrowth in LFC implants and failure force (r = 0.93, p 10

To evaluate the role and growth of independently billing otolaryngology (ORL) advanced practice providers (APPs) within a Medicare population.Retrospective cross-sectional study.Medicare Provider Utilization and Payment Data: Physician and Other Supplier Data Files, 2012-2017.This retrospective review included data and analysis of independent Medicare-billing ORL APPs. Total sums and medians were gathered for Medicare reimbursements, services performed, number of patients, and uniqueThere has been near-linear growth in number of ORL APPs (13.7% to 18.4% growth per year), with a 115.4% growth from 2012 to 2017. Similarly, total Medicare-allowed reimbursement (2012: $15,568,850; 2017: $35,548,446.8), total number of services performed (2012: 313,676; 2017: 693,693.7), and total number of Medicare fee-for-service (FFS) patients (2012: 108,667; 2017: 238,506) increased. Medians of per APP number of uniqueAlthough their scope of practice has remained constant, independently billing ORL APPs are rapidly increasing in number, which has led to increased Medicare reimbursements, services, and patients. ORL APPs tend to be female and are used more heavily in regions with fewer ORL physicians.

Posterior nasal nerve (PNN) cryoablation is a novel surgical technique used to address chronic rhinitis. The purpose of this study is to review the medical device reports (MDRs) submitted to the Food and Drug Administration's (FDA) Manufacturer and User Device Facility Experience (MAUDE) database to identify adverse events related to the use of ClariFix, a device designed for office-based cryosurgical ablation of the PNN. A total of 12 adverse events associated with ClariFix from January 2017 to August 2020 were identified and analyzed. The most common adverse events associated with ClariFix PNN cryoablation include epistaxis and nasal swelling. Further studies are needed to clarify whether PNN cryoablation is associated with epistaxis in certain populations.

OBJECTIVE To characterize reimbursement trends and providers for chronic migraine (CM) chemodenervation treatment within the Medicare population since the introduction of the migraine-specific CPT code in 2013. METHODS We describe trends in procedure volume and total allowed charge on cross-sectional data obtained from 2013 to 2018 Medicare Part B National Summary files. We also utilized the 2017 Medicare Provider Utilization and Payment Data to analyze higher volume providers (>10 procedures) of this treatment modality. RESULTS The total number of CM chemodenervation treatments rose from 37,863 in 2013 to 135,023 in 2018 in a near-linear pattern (r = 0.999) and total allowed charges rose from ~$5,217,712 to $19,166,160 (r = 0.999). The majority of high-volume providers were neurologists (78.4%; 1060 of 1352), but a substantial proportion were advanced practice providers (APPs) (10.2%; 138 of 1352). Of the physicians, neurologists performed a higher mean number of procedures per physician compared to non-neurologists (59.6 [95% CI: 56.6-62.6] vs. 45.4 [95% CI: 41.0-50.0], p

Objective(s) Endocannabinoid pathways have been proposed to affect the underlying pathophysiology of tinnitus. The aim of this study is to evaluate the scope and findings of existing literature on the relationship between cannabis and cannabinoid pathways and tinnitus. Methods We conducted a review of animal, clinical and survey studies investigating the relationship between the use of cannabis‐derived agents and tinnitus. Using pertinent keywords and MeSH terms on PubMed, relevant studies were identified, yielding four animal studies, two large cross‐sectional survey studies, one clinical cross‐over study, and one case report. Results Animal studies revealed that cannabinoid receptor expression in the cochlear nucleus varied with tinnitus symptomatology and the use of cannabinoid agents either increased or had no effect on tinnitus‐related behavior. Survey studies yielded conflicting results between cannabis use and tinnitus in the general population. Clinical data is largely lacking, although a small cohort study showed a dose‐dependent relationship between tetrahydrocannabinol consumption and frequency of tinnitus episodes in patients receiving treatment for cancer. Conclusion While animal studies have revealed that cannabinoid receptors likely have a role in modulating auditory signaling, there is no compelling data either from animal or human studies for the use of cannabinoids to alleviate tinnitus. Further research is necessary to elucidate their precise role to guide development of therapeutic interventions. Level of Evidence NA., The aim of this review article is to evaluate the scope and findings of existing literature on the relationship between cannabis and cannabinoid pathways and tinnitus. While animal studies have revealed that cannabinoid receptors likely have a role in modulating auditory signaling, there is no compelling data either from animal or human studies for the use of cannabinoids to alleviate tinnitus.

To (1) summarize strategies proposed in the recent otolaryngology-head and neck surgery (OTO-HNS) literature for improving the residency application and selection process, (2) evaluate the effects of recently implemented changes to the OTO-HNS match, and (3) discuss recommendations for future changes to the OTO-HNS residency application and selection process.PubMed, Medline Ovid database, and article reference lists.A structured literature search was performed to identify current English language articles relating to the objectives of this study using the aforementioned data sources, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. The search was limited to submissions published between January 1, 2015, and January 1, 2020.Numerous proposals have been made for improving the otolaryngology residency application and selection process and addressing the competitive nature of the Match. These proposals include but are not limited to mandating a secondary essay, implementing consortia and early match processes, using a signaling system, conducting regional and web-based interviews, offering early engagement with interest groups, instituting a hard cap on applications, increasing costs of applying, counseling self-restraint to prospective applicants, and creating application filters.As the volume of literature surrounding the OTO-HNS Match continues to increase, this review aims to provide a summary of past proposals and serve as a guide for possible future innovations. We propose 3 initiatives that may improve the residency application and selection process for both program and resident, with minimal impact to the current National Resident Matching Program (NRMP) Match structure.

The practice of otolaryngology has been drastically altered as a consequence of the ongoing coronavirus disease 2019 (COVID-19) pandemic. Geographic heterogeneity in COVID-19 burden has meant different regions have experienced the pandemic at different stages. Regional dynamics of COVID-19 incidence has dictated the available resources for the provision of surgical care. As regions navigate their own COVID-19 dynamics, illustrative examples of areas affected early by the COVID-19 pandemic may provide anticipatory guidance. In this commentary, we discuss our experience with performed and canceled surgical procedures across the various otolaryngology specialties at our institution over the course of regionally rising and falling incident COVID-19 cases.

To evaluate postoperative opiate use and patients' opinions regarding pain management after endoscopic sinus surgery (ESS).Case series with planned data collection.Tertiary referral medical center.We prospectively evaluated postoperative opiate utilization in adults undergoing ESS over a 2-year period at an academic medical facility. Exclusion criteria included use of nasal packing, intracranial or orbital procedures, tumor surgery, and any use of endoscopic drills. All patients underwent bilateral maxillary antrostomy, total ethmoidectomy, sphenoidotomy, and frontal sinusotomy with or without septoplasty. Patients were discharged with 30 oxycodone-acetaminophen (5-325 mg) and a survey assessing pain and narcotic/nonnarcotic use on postoperative days 0 to 7.A total of 64 patients completed surveys. Mean ± SD narcotic use over the 7-day postoperative period was 7.7 ± 7.6 pills. Patients with high narcotic use (6 pills total) had no differences in demographic or surgical factors from those with low use (≤6 pills) but did report a higher level of postoperative day 1 pain (4.8 ± 1.1 vs 2.0 ± 1.4,Our results support reduced opiate prescription and encouragement of nonnarcotic use after ESS without compromising effective pain management.

Background Improving the quality of healthcare is a complex and resource intensive process. To optimize the allocation of scarce resources, quality improvement (QI) should focus on high-value diseases that will produce the largest improvement in health system performance. Given the breadth and multidisciplinary nature of sinonasal disease management, the purpose of this study was to transparently develop a prioritized list of sinonasal diseases for QI from the perspective of the specialty of rhinology and the American Rhinologic Society (ARS). Methods The RAND modified Delphi methodology was used to rank the priority of nine sinonasal disease categories from 1 (lowest priority) to 9 (highest priority). Two rounds of ranking along with a teleconference meeting was performed by a panel of 9 experts from the ARS Quality Improvement Committee. Results The final QI-prioritized list of sinonasal diseases are as follows: chronic rhinosinusitis (CRS) (mean score = 8.9), recurrent acute rhinosinusitis (RARS) (mean score = 7.9), sinonasal neoplasms (mean score = 7.0), anatomic nasal obstruction (mean score = 5.9), refractory epistaxis (mean score = 5.2), complicated acute rhinosinusitis (mean score = 5.2), chronic nonallergic rhinitis (mean score = 4.4), orbital disease (mean score = 4.3), uncomplicated acute rhinosinusitis (mean score = 4.1), and allergy/allergic rhinitis (mean score = 3.7). Conclusion The three most important disease categories for QI from the perspective of the specialty of rhinology were CRS, RARS, and sinonasal neoplasms. Future studies need to define and validate quality metrics for each of these important disease categories in order to facilitate appropriate measurement and improvement initiatives.

The generality of ecological patterns depends inextricably on the scale at which they are examined. We investigated patterns of crab distribution and the relationship between crabs and vegetation in salt marshes at multiple scales. By using consistent monitoring protocols across 15 U.S. National Estuarine Research Reserves, we were able to synthesize patterns from the scale of quadrats to the entire marsh landscape to regional and national scales. Some generalities emerged across marshes from our overall models, and these are useful for informing broad coastal management policy. We found that crab burrow distribution within a marsh could be predicted by marsh elevation, distance to creek and soil compressibility. While these physical factors also affected marsh vegetation cover, we did not find a strong or consistent overall effect of crabs at a broad scale in our multivariate model, though regressions conducted separately for each site revealed that crab burrows were negatively correlated with vegetation cover at 4 out of 15 sites. This contrasts with recent smaller-scale studies and meta-analyses synthesizing such studies that detected strong negative effects of crabs on marshes, likely because we sampled across the entire marsh landscape, while targeted studies are typically limited to low-lying areas near creeks, where crab burrow densities are highest. Our results suggest that sea-level rise generally poses a bigger threat to marshes than crabs, but there will likely be interactions between these physical and biological factors. Beyond these generalities across marshes, we detected some regional differences in crab community composition, richness, and abundance. However, we found striking differences among sites within regions, and within sites, in terms of crab abundance and relationships to marsh integrity. Although generalities are broadly useful, our findings indicate that local managers cannot rely on data from other nearby systems, but rather need local information for developing salt marsh management strategies.

Background The potential for patient misconceptions about endoscopic sinus surgery (ESS) has implications for the informed consent process. An understanding of patients’ baseline knowledge and sources of information regarding ESS would improve surgeons’ ability to counsel patients preoperatively and provide effective educational materials. Methods A prospective patient survey was performed at 2 independent tertiary care medical centers. Patients who were offered ESS as part of routine rhinology care were queried about expectations, knowledge, and sources of information regarding ESS before preoperative counseling. Results Of the 30 patients who completed the survey, 70% of patients reported doing research on ESS before the visit. The most common sources of information were friends and family (40%), YouTube (30.0%), and WebMD (26.7%). The most important factors researched included risks (95%), benefits (85%), and recovery related issues (70%). Patients in the younger group used healthcare and physician rating websites whereas none of the patients older than the median age of 44 years reported using them (33.3% vs 0%, p = 0.028). The older group more often relied upon healthcare providers than the younger group (71.5% vs 18.8%, p = 0.011). A range of responses were noted regarding early postoperative symptoms and recovery time. Conclusion This study identified a varied understanding of ESS including significant misconceptions about risks, anesthesia, and need for ongoing therapy, among others. Patients obtain their information from a variety of sources including peers, other doctors, and the Internet. Awareness of the gaps in patient knowledge and the sources of information will improve preoperative counseling.

Background Nasal steroids are a critical part of the management of patients with chronic rhinosinusitis with nasal polyposis (CRSwNP) after endoscopic sinus surgery (ESS). Increasingly, practitioners are using budesonide respules delivered to the sinonasal cavities, which is an off-label use, in lieu of traditional nasal steroids. There has been little research comparing budesonide with traditional nasal steroids and the most effective delivery method of budesonide. Methods A randomized controlled trial was performed on patients after ESS for CRSwNP in a tertiary care center. Patients were randomized into 1 of 3 groups: group A received fluticasone nasal spray twice daily; group B received budesonide respules via a mucosal atomization device (MAD) twice daily; and group C received budesonide respules instilled via the vertex-to-floor (VF) position twice daily. Primary endpoints were 22-item Sino-Nasal Outcome Test (SNOT-22) and Lund-Kennedy scores at 6 months. Results Thirty-two patients were enrolled in the study, 23 of whom completed the 6-month trial. There were no significant differences among groups A, B, and C with respect to age, gender, asthma, aspirin sensitivity, or previous ESS. Group B had a statistically significant greater reduction in SNOT-22 and Lund-Kennedy scores at the primary endpoint of 6 months compared to groups A and C. Group C had the next greatest reduction, which was statistically significant, followed by group A. Conclusion Patients treated with budesonide after ESS for CRSwNP had greater improvement in SNOT-22 and Lund-Kennedy scores compared to fluticasone at 6 months. The data supports the use of budesonide respules, particularly with a MAD, over fluticasone for CRSwNP patients after ESS.

In several European countries, preparation of cellular products with open manufacturing systems as used for cryopreservation of peripheral blood stem cells (PBSCs) needs to be performed in a clean-room facility. However, this form of manufacturing is highly expensive and laborious. Thus, safe techniques providing improved efficacy regarding time and material, which are in accordance with legal requirements are highly desirable.We have developed, validated, and applied a simple method for cryopreservation of PBSCs within a functionally closed-bag system using the closed cryo freeze prep set. This process fulfills good manufacturing practice requirements and allows for the cryopreservation of PBSCs without a clean-room facility. In addition to cryopreservation of PBSCs, we have recently successfully modified our system for processing, portioning, and cryopreservation of allogeneic donor lymphocytes.Since 2010, cryopreservation of PBSCs using a closed-bag system has been performed in our facility on a routine basis and 210 patients and healthy donors have been included in this analysis. No significant reduction in viability of CD34+ cells and no process-related contamination were observed. Outcome of hematopoietic stem cell transplantation regarding time of engraftment and infectious complications is comparable to products manufactured in conventional clean-room facilities.Our data confirm that cryopreservation of PBSCs within a functionally closed-bag system is safe, effective, and economical. Furthermore, the system has the potential to be extended to other manufacturing processes of cellular products.

Background: Sarcoidosis is a chronic disease process characterized by non-caseating granulomatous inflammation, usually involving the lower respiratory tract. Given the rarity of rhinologic involvement, the objectives of the present study were (1) to describe clinical features, and (2) to review outcomes of rhinologic surgery for sinonasal sarcoidosis. Methods: Retrospective analysis was performed of patients evaluated at a tertiary care referral center between January 2006 and July 2011. Results: The mean age of the 38 patients with sinonasal sarcoidosis was 52 years, with a female:male ratio of 2.8:1. The most common presenting symptoms included nasal obstruction (65.8%), crusting (29.9%), and epistaxis (18.4%). Most frequent endoscopic findings included crusting (55.3%), mucosal thickening (44.7%), and subcutaneous nodules (21%). Computed tomography (CT) imaging demonstrated turbinate or septal nodularity (21%), osteoneogenesis (15.8%), and bone erosion (10.5%). Medical management was typically comprised of saline irrigations (73.3%), topical nasal steroids (68.4%), and oral steroids (63.2%). Refractory sinus symptoms required sinonasal surgery in 4 cases. Overall subjective symptom improvement was noted in 39.5% at mean follow-up of 16.2 months. Conclusion: Sinonasal involvement was noted in approximately 30% of patients with known sarcoidosis evaluated in the otolaryngology clinic. Patients typically present with nasal obstruction and endoscopic evidence of crusting and mucosal thickening. Medical therapy with irrigations and topical/oral steroids suffices in majority of patients, with surgery for refractory symptoms being required in a small subset of cases. C � 2013 ARS-AAOA, LLC.

Richards, R. Peter, Ibrahim Alameddine, J. David Allan, David B. Baker, Nathan S. Bosch, Remegio Confesor, Joseph V. DePinto, David M. Dolan, Jeffrey M. Reutter, and Donald Scavia, 2012. Discussion –“Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models” by Dale M. Robertson and David A. Saad. Journal of the American Water Resources Association (JAWRA) 1-10. DOI: 10.1111/jawr.12006 Abstract: Results from the Upper Midwest Major River Basin (MRB3) SPARROW model and underlying Fluxmaster load estimates were compared with detailed data available in the Lake Erie and Ohio River watersheds. Fluxmaster and SPARROW estimates of tributary loads tend to be biased low for total phosphorus and high for total nitrogen. These and other limitations of the application led to an overestimation of the relative contribution of point sources vs. nonpoint sources of phosphorus to eutrophication conditions in Lake Erie, when compared with direct estimates for data-rich Ohio tributaries. These limitations include the use of a decade-old reference point (2002), lack of modeling of dissolved phosphorus, lack of inclusion of inputs from the Canadian Lake Erie watersheds and from Lake Huron, and the choice to summarize results for the entire United States Lake Erie watershed, as opposed to the key Western and Central Basin watersheds that drive Lake Erie’s eutrophication processes. Although the MRB3 SPARROW model helps to meet a critical need by modeling unmonitored watersheds and ranking rivers by their estimated relative contributions, we recommend caution in use of the MRB3 SPARRROW model for Lake Erie management, and argue that the management of agricultural nonpoint sources should continue to be the primary focus for the Western and Central Basins of Lake Erie.

The focus of this study is the nature and concomitants of pretend play among young children with autism. Age- and language-matched children with autism (n= 27), autism spectrum disorder (n= 14), and developmental disorders without autism (n= 16) were administered the Test of Pretend Play (ToPP; Lewis & Boucher, 1997), with an additional rating of 'playful pretence'. As predicted, children with autism showed less playful pretend than participants with developmental disorders who did not have autism. Across the groups, playful pretence was correlated with individual differences in communication and social interaction, even when scores on the ToPP were taken into account. Limitations in creative, playful pretend among children with autism relate to their restricted interpersonal communication and engagement.

Background The purpose of this work was to perform a systematic review regarding ossifying fibroma and its multiple variants of the paranasal sinuses, and to identify any clinical differences between the multiple variants. A search of the U.S. National Library of Medicine (PubMed) database was performed for the non–Medical Subject Heading (MeSH) search term “ossifying fibroma.” The bibliographies of the retrieved manuscripts were searched to identify additional potentially relevant articles. Finally, textbooks of head and neck pathology were searched to identify peer-reviewed literature that addresses the histopathology of ossifying fibroma and its variants. Abstracts were screened by 2 of the authors to identify reports of ossifying fibroma lesions (and its variants) that involved the paranasal sinuses. Extracted data from case reports or case series included the clinical presentation, age, gender, site of involvement, surgical approach, treatment outcome, follow-up period, and recurrence rate. Information derived from cases is summarized in tables, and simple descriptive statistics were applied to the data. A total of 137 distinct patients were identified in 103 reports. Extracted data did not show any appreciable difference in clinical presentation or outcomes. Data on recurrence of these lesions was often limited by a lack of follow-up. Although differentiation between the subtypes of ossifying fibroma can be made histologically, and a diverse nomenclature exists, there does not appear to be any overriding clinical significance to the histopathologic differentiation of OF variants. Methods A search of the U.S. National Library of Medicine (PubMed) database was performed for the non–Medical Subject Heading (MeSH) search term “ossifying fibroma.” The bibliographies of the retrieved manuscripts were searched to identify additional potentially relevant articles. Finally, textbooks of head and neck pathology were searched to identify peer-reviewed literature that addresses the histopathology of ossifying fibroma and its variants. Abstracts were screened by 2 of the authors to identify reports of ossifying fibroma lesions (and its variants) that involved the paranasal sinuses. Extracted data from case reports or case series included the clinical presentation, age, gender, site of involvement, surgical approach, treatment outcome, follow-up period, and recurrence rate. Information derived from cases is summarized in tables, and simple descriptive statistics were applied to the data. A total of 137 distinct patients were identified in 103 reports. Extracted data did not show any appreciable difference in clinical presentation or outcomes. Data on recurrence of these lesions was often limited by a lack of follow-up. Although differentiation between the subtypes of ossifying fibroma can be made histologically, and a diverse nomenclature exists, there does not appear to be any overriding clinical significance to the histopathologic differentiation of OF variants. Results A total of 137 distinct patients were identified in 103 reports. Extracted data did not show any appreciable difference in clinical presentation or outcomes. Data on recurrence of these lesions was often limited by a lack of follow-up. Although differentiation between the subtypes of ossifying fibroma can be made histologically, and a diverse nomenclature exists, there does not appear to be any overriding clinical significance to the histopathologic differentiation of OF variants. Conclusion Although differentiation between the subtypes of ossifying fibroma can be made histologically, and a diverse nomenclature exists, there does not appear to be any overriding clinical significance to the histopathologic differentiation of OF variants.

Background: The objective of this study was to prospectively evaluate the clinical impact of intraoperative computed tomography (CT) imaging on endoscopic sinonasal and skull base procedures. Methods: A total of 49 patients were enrolled after informed consent from December 2009 to May 2010. Patients underwent intraoperative volume CT imaging (xCAT, Xoran Technologies, Ann Arbor, MI) at the conclusion of their proposed surgery. Results: The mean age was 48.6 years with male:female ratio of 1.3:1. Surgical procedures included revision or primary endoscopic sinonasal surgery (ESS) (36), endoscopic benign or malignant tumor resection (10), endoscopic mucocele drainage (2), and endoscopic tumor biopsy (1). The mean Lund-Mackay (L-M) score was 10.6 (range 1-21). The indications for intraoperative imaging included extent of paranasal sinus dissection in 38 (77.6%), extent of tumor resection in 11 (22.4%), adequacy of mucocele drainage in 3 (6.1%), and frontal stent position in 2 (4.1%) cases. Average acquisition time was 5.3 minutes. The CT acquisition quality was deemed excellent in 24 (49.0%), good in 15 (30.6%), fair in 5 (10.2%), and unattainable in 5 (10.2%) cases. Additional interventions were performed in 8 of 44 cases (18%) based on the intraoperative CT dataset. Analysis of predictive factors for additional intervention, including presence of polyps, presence of tumor, previous surgery, use of image guidance, and CT quality did not reach statistical significance. Conclusion: Intraoperative CT scanning may hold important utility in selected endoscopic sinonasal and skull base procedures with additional interventions being performed in 18% of cases. The present study was unable to identify specific factors that would preoperatively predict the need for intraoperative imaging. Future clinical trials should include a multi-institutional design to better delineate these important variables. © 2011 ARS-AAOA, LLC.

Extended end-member mixing analysis (E-EMMA) is presented as a novel empirical method for exploring phosphorus (P) retention and release in rivers and watersheds, as an aid to water-quality management. E-EMMA offers a simple and versatile tool that relies solely on routinely measured P concentration and flow data. E-EMMA was applied to two river systems: the Thames (U.K.) and Sandusky River (U.S.), which drain similar watershed areas but have contrasting dominant P sources and hydrology. For both the Thames and Sandusky, P fluxes at the watershed outlets were strongly influenced by processes that retain and cycle P. However, patterns of P retention were markedly different for the two rivers, linked to differences in P sources and speciation, hydrology and land use. On an annual timescale, up to 48% of the P flux was retained for the Sandusky and up to 14% for the Thames. Under ecologically critical low-flow periods, up to 93% of the P flux was retained for the Sandusky and up to 42% for the Thames. In the main River Thames and the Sandusky River, in-stream processes under low flows were capable of regulating the delivery of P and modifying the timing of delivery in a way that may help to reduce ecological impacts to downstream river reaches, by reducing ambient P concentrations at times of greatest river eutrophication risk. The results also suggest that by moving toward cleaner rivers and improved ecosystem health, the efficiency of P retention may actually increase.