Long term study on the effects of microsurgical DREZotomy for chronic pain control

The DREZotomy (Dorsal Root Entry Zone tomy) is an analgesic procedure. The analgesic effect is evaluated on 30 patients with chronic pain resulting from respectively: brachial plexus avulsion (66.6%), postherpetic pain (10%), hyperspastic states (6.6%), phantom pain (6.6%), the pain in the stump (6.6%), and spinal cord injuries (3.3%). Pain intensity was evaluated using a visual analogue scale (VAS). At last evaluation, between 12 and 60 months, after DREZotomy, 93% had a good or excellent global pain relief after surgery. According to the component types of pain, 9.6% of patients had good or excellent control of the paroxysmal pain, and 84% of the continuous pain. Kaplan–Meier prediction of lasting global pain control at 60 months of follow-up was calculated at 75.5%. Comparison of the 2 corresponding Kaplan–Meier curves at long term, namely, pain control in 82.8% for the paroxysmal component and in 51.7% for the continuous component, showed a statistically significant difference (P < 0.0001). Functional effects are improved by more than 70% according to patients.

Download Full-text

Short and Long Term Outcome In Patients with Calcified Lesions Requiring Rotational Artherectomy

Bangladesh Heart Journal ◽

10.3329/bhj.v35i2.52901 ◽

2021 ◽

Vol 35 (2) ◽

pp. 140-146

Author(s):

Lima Asrin Sayami ◽

Al Fazir Omar ◽

Sheikh Ziarat Islam ◽

Subasni Govindan ◽

Zulaikha Zainal ◽

...

Keyword(s):

P Value ◽

Success Rates ◽

Term Outcome ◽

Long Term Outcome ◽

Operator Experience ◽

Kaplan Meier ◽

Significant Difference ◽

Short And Long Term ◽

Procedural Success

Objective: Despite the evolution of interventional techniques and operator experience, percutaneous revascularization of complex coronary lesions especially calcified lesions remains challenging because of lower procedural success and higher restenosis rates. Limited data are available on the effect of rotational atherectomy (RA) plus stenting in the treatment of complex calcified lesions of coronary artery disease. This study was aimed to investigate the characteristics, short and long term outcomes in patients undergoing RA. Material and Methods: A database search was performed from the year 2008 to 2013 in National Heart institute, Malaysia. A total of 16009 patients who underwent PCIs were enrolled in 2 groups, RA group (258 patients) and non RA group (15751 patients). The Chi square test and Kaplan - Meier analysis were used. Results: Male patients (73.6%) and elderly population (63.2%) were predominant in this study.The RA group had more co-morbidities such as diabetic on insulin (34%) and chronic kidney disease (57%). The lesions in RA group were more complex with higher Type C lesion (68.8%) and longer lesion (20.6%) compared to non RA group. Despite higher patient risk profile, the success rate of revascularization remains high in RA group (99.3%) as in non RA group (97%) (p value 0.89%). More importantly there were no significant difference in in-hospital mortality, myocardial infarction and stent thrombosis in both group (p value 0.1). In 1 year Kaplan - Meier survival graph, there were better survival noted in non RA group (97.7%) compare to RA (89.6%) (p value <0.005), Conclusion: The use of RA allows debulking of a calcified lesion and possibly explains the higher acute procedural success rates. However, the lower 1-yearsurvival in the RA group highlights the higher associated baseline comorbitidity in this group. Therefore, besides coronary intervention, this RA group requires aggressive medical therapy through a multi-disciplinary approach. Bangladesh Heart Journal 2020; 35(2) : 140-146

Download Full-text

Long-term functional outcomes of different subtypes of primary congenital glaucoma

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2019-315131 ◽

2019 ◽

pp. bjophthalmol-2019-315131 ◽

Cited By ~ 2

Author(s):

Richard Sher Chaudhary ◽

Amisha Gupta ◽

Ajay Sharma ◽

Shikha Gupta ◽

Rayees Ahmad Sofi ◽

...

Keyword(s):

Visual Acuity ◽

Congenital Glaucoma ◽

Cumulative Probability ◽

Primary Congenital Glaucoma ◽

Visual Outcomes ◽

Post Surgery ◽

Kaplan Meier ◽

Significant Difference

AimTo analyse long-term visual outcomes across different subtypes of primary congenital glaucoma (PCG).MethodsPatients with PCG with a minimum of 5-year follow-up post surgery were included in the study. Snellen visual acuity recordings taken at their last follow-up were analysed. We evaluated the results using Kaplan-Meier curves to predict the probability of maintaining good vision (as defined by a visual acuity of 6/18 or better) in our patients after 30-year follow-up. The results were also analysed to determine whether there were any differences in the long-term visual acuities with time between the neonatal and infantile PCG. We also analysed the reasons for poor visual outcomes.ResultsWe assessed a cohort of 140 patients with PCG (235 eyes) with an average follow-up of 127±62.8 months (range 60–400 months). Overall, the proportion of eyes with good visual acuity was 89 (37.9%), those with fair visual acuity between 6/60 and 6/18 was 41 (17.4%), and those with poor visual acuity (≤6/60) was 105 (44.7%). We found a significant difference (p=0.047) between neonatal and infantile patients with PCG whereby the neonatal cohort fared worse off in terms of visual morbidity. On Kaplan-Meier analysis, the cumulative probability of survival of a visual acuity of 6/18 or better was more among the infantile PCG in comparison to the neonatal PCG (p=0.039) eyes, and more among the bilateral than the unilateral affected eyes (p=0.029). Amblyopia was the most important cause for poor visual acuity as shown on a Cox proportional-hazards regression model .ConclusionsLong-term visual outcomes of infantile are better than neonatal PCG. Eyes with unilateral have worse visual outcomes compared with those with bilateral PCG because of the development of dense amblyopia.

Download Full-text

Clinical features and long-term outcomes of moyamoya disease: a single-center experience with 528 cases in China

Journal of Neurosurgery ◽

10.3171/2014.10.jns132369 ◽

2015 ◽

Vol 122 (2) ◽

pp. 392-399 ◽

Cited By ~ 56

Author(s):

Xing-ju Liu ◽

Dong Zhang ◽

Shuo Wang ◽

Yuan-li Zhao ◽

Mario Teo ◽

...

Keyword(s):

Clinical Features ◽

Moyamoya Disease ◽

Positive Impact ◽

Chinese Patients ◽

Single Center ◽

Long Term Outcomes ◽

Kaplan Meier ◽

Significant Difference ◽

Revascularization Procedures

OBJECT The aim of this study was to describe the baseline clinical features and long-term outcomes of patients with moyamoya disease (MMD) based on a 25-year period at a single center in China. METHODS Data obtained in 528 consecutive patients with MMD treated at the authors' hospital from 1984 to 2010 were reviewed retrospectively. Events of transient ischemic attack, new infarction, and hemorrhage were included. The Kaplan-Meier risk of stroke was calculated. RESULTS The mean (± SD) patient age was 26 ± 13 years (range 2–67 years), and the female/male ratio was 0.9:1. There were 332 cases of ischemia and 196 hemorrhages. Adults had a higher rate of bleeding than children (50.7% vs 14.0%, respectively; p < 0.001). One hundred twenty-two patients were treated conservatively, and 406 patients underwent revascularization procedures. Of 528 patients, 331 (62.7%) had at least 1 year of follow-up (median 39.5 months) and data from these patients were analyzed. Rebleeding and mortality rates in patients with hemorrhagic MMD (n = 104) were higher than in those with ischemic MMD (n = 227) (26.9% vs 2.2% [p < 0.001] and 4.8% vs 0.4% [p < 0.05], respectively). Twenty-five of 60 (41.7%) conservatively treated patients and 8 of 271 (2.9%) surgically treated patients experienced rebleeding events, a difference that was significant in the Kaplan-Meier curve of rebleeding (p < 0.01). An improvement in perfusion was found in 164 of 224 (73.2%) surgically treated patients 1 month after discharge. However, there was no significant difference in the rate of ischemic events in the surgical and conservative groups (18.8% and 28.3%, respectively; p = 0.09). Among the 104 hemorrhagic cases, rebleeding attacks were observed in 25 patients in the nonsurgical group (n = 60) and 3 patients in the surgical group (n = 44) (41.7% and 6.8%, respectively; OR 9.7 [95% CI 2.7–35.0]; p < 0.01). CONCLUSIONS There was no difference in the sex distribution of Chinese patients with MMD. Patients with hemorrhagic MMD had a much higher rate of rebleeding and poorer prognosis than those with the ischemic type. Surgical revascularization procedures can improve cerebral perfusion and have a positive impact in preventing rebleeding in patients with hemorrhagic MMD.

Download Full-text

Sleeve lobectomy an affidable lung sparing procedure

Journal of Clinical Oncology ◽

10.1200/jco.2006.24.18_suppl.17159 ◽

2006 ◽

Vol 24 (18_suppl) ◽

pp. 17159-17159

Author(s):

G. Cavallesco ◽

P. Maniscalco ◽

F. Quarantotto ◽

F. Acerbis ◽

M. Santini ◽

...

Keyword(s):

Main Bronchus ◽

Rank Test ◽

Sleeve Lobectomy ◽

Term Survival ◽

Average Hospital ◽

Long Term Survival ◽

Kaplan Meier ◽

Significant Difference ◽

Similar Survival

17159 Background: Sleeve Lobectomy (Sl) is generally considered a surgical alternative of choice to Pneumonectomy (Pn) for the treatment of central NSCLC. The aim of this study is to value if the Sl could be really a Lung saving procedure that warrants right survivals, according to stage of disease, with acceptable perioperative risks. Methods: In 165 patients (67 Sl and 98 Pn) operated from 1995 to 2003 for NSCLC of main bronchus we have analyzed the hospital stay, morbidity and mortality within 30 days, long term survival. In 39 Sl and 46 Pn we compared spyrometric volume’s changes at a distance of 6–24 months from operation. Sl was performed where it was technically possible. Long term survivals had been separated and comparated according to pathologic stadium (TNM 1997) and lymphonodal involvement: all these data were estimated by Kaplan-Meier method and log rank test. All statistical data underwent SPSS elaboration and significant assumption for p < 0.05. Results: In our population of study we didn’t check any statistically significant’s differences comparing age, sex or preoperative Fev1. Complications occurred in 28% of cases where Sl was performed and in 36.7% after Pn with a mortality rate of 2.9% vs 5.1%. Average hospital staying was longer in patients underwent to Pneumonectomy. Long term survival (5 years) in Sl group is 36% and 24% in Pn group with a statistically significant difference P = 0.016, but this difference is not evident from the comparison between the two group’s survivals based on pathological stadium or lymphonodal involvement. Spyrometric values showed a global Fev1 reduction of 245 ml (−10%) after Sl procedure and 884ml (36.3%) after Pn with a significant difference of p = 0.0042. Conclusions: In this study Sl got similar survival results if not better, with those obtained after Pn. Moreover, Sl showed to be a lung sparing procedure with an acceptable operative risk. These data confirmed that SL is the gold standard surgical procedure in the treatment of central tumors where if technically possible. [Table: see text] No significant financial relationships to disclose.

Download Full-text

Ankle Arthrodesis: A Long-term Study

Foot & Ankle ◽

10.1177/107110079201300602 ◽

1992 ◽

Vol 13 (6) ◽

pp. 307-312 ◽

Cited By ~ 79

Author(s):

Richard V. Abdo ◽

Stephen A. Wasilewski

Keyword(s):

Ankle Arthrodesis ◽

Radiographic Examination ◽

Radiographic Evaluation ◽

Grading System ◽

Term Study ◽

Evaluation Score ◽

Long Term Study ◽

Significant Difference

Few studies of ankle arthrodesis have assessed tarsal mobility. This study was performed to evaluate radiographically the effect of ankle arthrodesis on tarsal motion. Thirty patients (31 ankles) returned for clinical and radiographic examination, review of charts, and completion of questionnarie forms. Radiographs were evaluated for success of fusion, position of fusion, tarsal motion, hindfoot position, and subtalar and midtarsal arthritis. The median follow-up time was 7.0 years (range 2–20 years). Results showed that fusion was achieved in 22 patients (71%). The evaluation score based on the grading system of Mazur et al. 16 correlated with success of fusion and patient satisfaction. However, no correlation existed between evaluation score and tarsal motion or position of fusion in the sagittal or coronal planes. Radiographic evaluation showed no significant difference between tarsal motion of the fused side and the unfused side. Tarsal mobility was not affected by ankle arthrodesis or by the techniques performed to achieve fusion.

Download Full-text

Inequities in access to primary care among opioid recipients in Ontario, Canada: A population-based cohort study

PLoS Medicine ◽

10.1371/journal.pmed.1003631 ◽

2021 ◽

Vol 18 (6) ◽

pp. e1003631

Author(s):

Tara Gomes ◽

Tonya J. Campbell ◽

Diana Martins ◽

J. Michael Paterson ◽

Laura Robertson ◽

...

Keyword(s):

Primary Care ◽

Chronic Pain ◽

Cohort Study ◽

Prescription Opioid ◽

Opioid Use ◽

High Quality ◽

Significant Difference ◽

Ed Visits ◽

Access To Primary Care

Background Stigma and high-care needs can present barriers to the provision of high-quality primary care for people with opioid use disorder (OUD) and those prescribed opioids for chronic pain. We explored the likelihood of securing a new primary care provider (PCP) among people with varying histories of opioid use who had recently lost access to their PCP. Methods and findings We conducted a retrospective cohort study using linked administrative data among residents of Ontario, Canada whose enrolment with a physician practicing in a primary care enrolment model (PEM) was terminated between January 2016 and December 2017. We assigned individuals to 3 groups based upon their opioid use on the date enrolment ended: long-term opioid pain therapy (OPT), opioid agonist therapy (OAT), or no opioid. We fit multivariable models assessing the primary outcome of primary care reattachment within 1 year, adjusting for demographic characteristics, clinical comorbidities, and health services utilization. Secondary outcomes included rates of emergency department (ED) visits and opioid toxicity events. Among 154,970 Ontarians who lost their PCP, 1,727 (1.1%) were OAT recipients, 3,644 (2.4%) were receiving long-term OPT, and 149,599 (96.5%) had no recent prescription opioid exposure. In general, OAT recipients were younger (median age 36) than those receiving long-term OPT (59 years) and those with no recent prescription opioid exposure (44 years). In all exposure groups, the majority of individuals had their enrolment terminated by their physician (range 78.1% to 88.8%). In the primary analysis, as compared to those not receiving opioids, OAT recipients were significantly less likely to find a PCP within 1 year (adjusted hazard ratio [aHR] 0.55, 95% confidence interval [CI] 0.50 to 0.61, p < 0.0001). We observed no significant difference between long-term OPT and opioid unexposed individuals (aHR 0.96; 95% CI 0.92 to 1.01, p = 0.12). In our secondary analysis comparing the period of PCP loss to the year prior, we found that rates of ED visits were elevated among people not receiving opioids (adjusted rate ratio (aRR) 1.20, 95% CI 1.18 to 1.22, p < 0.0001) and people receiving long-term OPT (aRR 1.37, 95% CI 1.28 to 1.48, p < 0.0001). We found no such increase among OAT recipients, and no significant increase in opioid toxicity events in the period following provider loss for any exposure group. The main limitation of our findings relates to their generalizability outside of PEMs and in jurisdictions with different financial incentives incorporated into primary care provision. Conclusions In this study, we observed gaps in access to primary care among people who receive prescription opioids, particularly among OAT recipients. Ongoing efforts are needed to address the stigma, discrimination, and financial disincentives that may introduce barriers to the healthcare system, and to facilitate access to high-quality, consistent primary care services for chronic pain patients and those with OUD.

Download Full-text

Effect of Body Mass Index on the Prognosis of Liver Cirrhosis

Frontiers in Nutrition ◽

10.3389/fnut.2021.700132 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yue Yin ◽

Yiling Li ◽

Lichun Shao ◽

Shanshan Yuan ◽

Bang Liu ◽

...

Keyword(s):

Liver Cirrhosis ◽

Survival Rate ◽

Normal Weight ◽

Cumulative Survival Rate ◽

Weight Group ◽

Cumulative Survival ◽

Normal Weight Group ◽

Kaplan Meier ◽

Significant Difference

Objective: At present, the association of body mass index (BMI) with the prognosis of liver cirrhosis is controversial. Our retrospective study aimed to evaluate the impact of BMI on the outcome of liver cirrhosis.Methods: In the first part, long-term death was evaluated in 436 patients with cirrhosis and without malignancy from our prospectively established single-center database. In the second part, in-hospital death was evaluated in 379 patients with cirrhosis and with acute gastrointestinal bleeding (AGIB) from our retrospective multicenter study. BMI was calculated and categorized as underweight (BMI <18.5 kg/m2), normal weight (18.5 ≤ BMI < 23.0 kg/m2), and overweight/obese (BMI ≥ 23.0 kg/m2).Results: In the first part, Kaplan–Meier curve analyses demonstrated a significantly higher cumulative survival rate in the overweight/obese group than the normal weight group (p = 0.047). Cox regression analyses demonstrated that overweight/obesity was significantly associated with decreased long-term mortality compared with the normal weight group [hazard ratio (HR) = 0.635; 95% CI: 0.405–0.998; p = 0.049] but not an independent predictor after adjusting for age, gender, and Child–Pugh score (HR = 0.758; 95%CI: 0.479–1.199; p = 0.236). In the second part, Kaplan–Meier curve analyses demonstrated no significant difference in the cumulative survival rate between the overweight/obese and the normal weight groups (p = 0.094). Cox regression analyses also demonstrated that overweight/obesity was not significantly associated with in-hospital mortality compared with normal weight group (HR = 0.349; 95%CI: 0.096-1.269; p = 0.110). In both of the two parts, the Kaplan–Meier curve analyses demonstrated no significant difference in the cumulative survival rate between underweight and normal weight groups.Conclusion: Overweight/obesity is modestly associated with long-term survival in patients with cirrhosis but not an independent prognostic predictor. There is little effect of overweight/obesity on the short-term survival of patients with cirrhosis and with AGIB.

Download Full-text

DOP28 Medical and Surgical Outcomes in Isolated Internal Penetrating Crohn’s Disease: A Multi-Centre Experience

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjab073.067 ◽

2021 ◽

Vol 15 (Supplement_1) ◽

pp. S066-S067

Author(s):

G Sebepos-Rogers ◽

K Fragkos ◽

E Shakweh ◽

K Shah ◽

L Lake ◽

...

Keyword(s):

Medical Management ◽

Nutrition Status ◽

Septic Complication ◽

Cumulative Probability ◽

Complication Rates ◽

Therapeutic Trials ◽

Kaplan Meier ◽

Significant Difference ◽

Penetrating Crohn’S Disease

Abstract Background Isolated internal penetrating Crohn’s diseases (IIPCD) is the second most common fistulating phenotype yet remains poorly characterised in therapeutic trials. This study assessed long-term outcomes of IIPCD. Methods We performed a retrospective study on data collected from 6 IBD referral centres, screening imaging reports between January 2016 and April 2019, excluding perianal or enterocutaneous fistulation, resulting in 121 patients with IIPCD. Management was classified as no intervention, medical (new/optimised) or surgical. The primary endpoint was complete resolution (CR) of fistula at next two imaging reassessments, paired with symptom and nutrition status, as previously defined(Samimi et al., 2010). Secondary endpoint was combined CR and partial resolution (PR). Statistics: Fisher’s exact, Kaplan-Meier method (SPSS v.27). Results Of patients at IIPCD diagnosis, 21% had previous IBD-related surgery, 21% were on a current biologic, 41% immunomodulator and 41% no treatment. Fistulae were majority enteroenteric (55%) and enterocolonic (48%), minority genitourinary (7.4%), with median disease duration at IIPCD diagnosis of 64 months. Outcomes of 118 patients with ≥1 interval imaging were analysed. Initial management was: 25.4% (n=30) no intervention, 49.2% (n=59) medical, 25.4% (n=30) surgical. Of fistula characteristics, only abscess predicted surgery over medical management (OR 5.30, 95% CI 1.60–15.48 p=0.0061), Figure 1. At first reassessment, CR and PR for the three management cohorts was 13.3%, 12.1%, 66.7% and 20.0%, 46.6%, 26.7%, respectively. The cumulative probability of CR was significantly greater for surgery compared with no intervention and medical management (log-rank p<0.001), Figure 2, and sustained when excluding pre-existing biologic (log-rank p=0.007), Figure 3, or previous surgery history (log-rank p<0.001). As observed management was then adjusted, cohorts were re-stratified: 13.5% (n=16) no intervention only, 45.8% (n=54) any medical but no surgery, 40.7% (n=48) any surgery. At second reassessment, again surgery significantly predicted CR over other management (log-rank p<0.001), Figure 4, but this was lost using the less strict outcome of combined CR and PR (log-rank p=0.447). No baseline variables were predictive of CR by each management. 27.6% (16/58) and 6.7% (2/30) of initial medical and no intervention cohorts had subsequent surgery (median interval 6.7 and 50.1 months) but there was no significant difference in peri-operative parenteral nutrition or post-operative intra-abdominal septic complication rates between earlier or later surgery. Conclusion In this cohort, surgery increases the probability of resolution of IIPCD with medical therapy including biologics offering limited temporising effect.

Download Full-text

The Renfrew Unified Treatment for Eating Disorders and Comorbidity: Long-Term Effects of an Evidence-Based Practice Implementation in Residential Treatment

Frontiers in Psychiatry ◽

10.3389/fpsyt.2021.641601 ◽

2021 ◽

Vol 12 ◽

Cited By ~ 1

Author(s):

Heather Thompson-Brenner ◽

Simar Singh ◽

Taylor Gardner ◽

Gayle E. Brooks ◽

Melanie T. Smith ◽

...

Keyword(s):

Eating Disorders ◽

Eating Disorder ◽

Anxiety Sensitivity ◽

Experiential Avoidance ◽

Multilevel Models ◽

Sensitivity Index ◽

Evidence Based ◽

Long Term Study ◽

Significant Difference

Background: The Renfrew Unified Treatment for Eating Disorders and Comorbidity (UT) is a transdiagnostic, emotion-focused treatment adapted for use in residential group treatment. This study examined the effect of UT implementation across five years of treatment delivery.Methods: Data were collected by questionnaire at admission, discharge (DC), and 6-month follow-up (6MFU). Patient outcomes were measured by the Eating Disorder Examination-Questionnaire, Center for Epidemiologic Studies-Depression Scale, Brief Experiential Avoidance Questionnaire (BEAQ), Anxiety Sensitivity Index, and Southampton Mindfulness Scale. Data were analyzed for N = 345 patients treated with treatment-as-usual (TAU), and N = 2,763 treated with the UT in subsequent years.Results: Results from multilevel models demonstrated a significant interaction between implementation status (TAU vs. UT) and time, both linear and quadratic, for the depression, experiential avoidance, anxiety sensitivity, and mindfulness variables. Patients treated with the UT showed more improvement in these variables on average, as well as more rebound between DC and 6MFU. Results from multilevel models examining eating disorder outcome showed no significant difference between the TAU and UT for the full sample, but a significant three-way interaction indicated that the UT produced more improvement in the EDE-Q relative to the TAU particularly for patients who entered treatment with high levels of experiential avoidance (BEAQ score).Conclusion: This long-term study of a transdiagnostic, evidence-based treatment in residential care for eating disorders and comorbidity suggests implementation was associated with beneficial effects on depression and emotion function outcomes, as well as eating disorder severity for patients with high levels of baseline emotion regulation problems. These effects did not appear to diminish in the 5 years following initial implementation.

Download Full-text

Long-Term Study of Soluble Reactive Phosphorus Concentration in Fall Creek and Comparison to Northeastern Tributaries of Cayuga Lake, NY: Implications for Watershed Monitoring and Management

Water ◽

10.3390/w11102075 ◽

2019 ◽

Vol 11 (10) ◽

pp. 2075 ◽

Cited By ~ 1

Author(s):

O’Leary ◽

Johnston ◽

Gardner ◽

Penningroth ◽

Bouldin

Keyword(s):

Flow Rate ◽

Algal Blooms ◽

Soluble Reactive Phosphorus ◽

Phosphorus Concentration ◽

Term Study ◽

Long Term Study ◽

Cayuga Lake ◽

Significant Difference ◽

Reactive Phosphorus

This study focuses on soluble reactive phosphorus (SRP), a key driver of eutrophication worldwide and a potential contributor to the emerging global environmental problem of harmful algal blooms (HABs). Two studies of tributary SRP concentrations were undertaken in sub-watersheds of Cayuga Lake, NY, the subject of a total maximum daily load (TMDL) development process, due to phosphorus impairment of its southern shelf. The long-term study compared SRP concentration in Fall Creek in the 1970s with that in the first decade of the 2000s, thus spanning a period of change in phosphorus sources, as well as in regional climate. The spatial study used data collected between 2009 and 2018 and compared SRP concentrations in Fall Creek to levels in northeastern tributaries that flow into the lake close to areas where HABs have been problematic. SRP was measured using standard procedures. Flow-weighted mean SRP concentration ranged between 15.0 µg/L and 30.0 µg/L in all years studied in both the 1970s and 2000s, with the exception of 2010. Annual discharge in Fall Creek showed no trend between 1970 and 2018, but a higher proportion of high streamflow samples was captured in the 2000s compared to the 1970s, which resulted in proportionally increased SRP concentration in the latter time period. There was no significant difference in the SRP concentration—flow rate relationship between the two time periods. Adjusted for flow rate, SRP concentrations in Fall Creek have not changed over many decades. Increasing phosphorus contributions from growing population and urbanization since the 1970s may have been counterbalanced by improvements in wastewater treatment and agricultural practices. Mean SRP concentration in northeastern tributaries was significantly (p < 0.001) higher than in Fall Creek, likely reflecting more intense agricultural use and higher septic system density in the watersheds of the former. This finding justifies continued monitoring of minor northern tributaries. Future monitoring must emphasize the capture of high flow conditions. Historical stability and highly variable hydrology will slow the watershed response to management and confound the ability to detect changes attributable to decreased phosphorus inputs. Large scale monitoring on decadal timescales will be necessary to facilitate watershed management.

Download Full-text