A re-evaluation of the Endoscopic Third Ventriculostomy Success Score: a Hydrocephalus Clinical Research Network study

OBJECTIVE

The Hydrocephalus Clinical Research Network (HCRN) conducted a prospective study 1) to determine if a new, better-performing version of the Endoscopic Third Ventriculostomy Success Score (ETVSS) could be developed, 2) to explore the performance characteristics of the original ETVSS in a modern endoscopic third ventriculostomy (ETV) cohort, and 3) to determine if the addition of radiological variables to the ETVSS improved its predictive abilities.

METHODS

From April 2008 to August 2019, children (corrected age ≤ 17.5 years) who underwent a first-time ETV for hydrocephalus were included in a prospective multicenter HCRN study. All children had at least 6 months of clinical follow-up and were followed since the index ETV in the HCRN Core Data Registry. Children who underwent choroid plexus cauterization were excluded. Outcome (ETV success) was defined as the lack of ETV failure within 6 months of the index procedure. Kaplan-Meier curves were constructed to evaluate time-dependent variables. Multivariable binary logistic models were built to evaluate predictors of ETV success. Model performance was evaluated with Hosmer-Lemeshow and Harrell's C statistics.

RESULTS

Seven hundred sixty-one children underwent a first-time ETV. The rate of 6-month ETV success was 76%. The Hosmer-Lemeshow and Harrell's C statistics of the logistic model containing more granular age and etiology categorizations did not differ significantly from a model containing the ETVSS categories. In children ≥ 12 months of age with ETVSSs of 50 or 60, the original ETVSS underestimated success, but this analysis was limited by a small sample size. Fronto-occipital horn ratio (p = 0.37), maximum width of the third ventricle (p = 0.39), and downward concavity of the floor of the third ventricle (p = 0.63) did not predict ETV success. A possible association between the degree of prepontine adhesions on preoperative MRI and ETV success was detected, but this did not reach statistical significance.

CONCLUSIONS

This modern, multicenter study of ETV success shows that the original ETVSS continues to demonstrate good predictive ability, which was not substantially improved with a new success score. There might be an association between preoperative prepontine adhesions and ETV success, and this needs to be evaluated in a future large prospective study.

Shunt infection prevention practices in Hydrocephalus Clinical Research Network-Quality: a new quality improvement network for hydrocephalus management

OBJECTIVE

Knowledge-based tools used to standardize perioperative care, such as the shunt infection prevention protocol of the Hydrocephalus Clinical Research Network (HCRN), have demonstrated their ability to reduce surgeon-based and center-based variations in outcomes and improve patient care. The mere presence of high-quality evidence, however, does not necessarily translate into improved patient outcomes owing to the implementation gap. To advance understanding of how knowledge-based tools are being utilized in the routine clinical care of children with hydrocephalus, the HCRN-Quality (HCRNq) network was started in 2019. With a focus on CSF shunt infection, the authors present baseline data regarding CSF shunt infection rates and current shunt infection prevention practices in use at HCRNq sites.

METHODS

Baseline shunt surgery practices, infection rate, and risk factor data were prospectively collected within HCRNq. No standard infection protocol was recommended, but site use of a protocol was implied if at least 3 of 6 common shunt infection prevention practices were used in > 80% of shunt surgical procedures. Univariable and multivariable analyses of shunt infection risk factors were performed.

RESULTS

Thirty sites accrued data on 2437 procedures between November 2019 and June 2021. The unadjusted infection rate across all sites was 3.9% (range 0%-13%) and did not differ among shunt insertion, shunt revision, or shunt insertion after infection. Protocol use was implied for only 15/30 centers and 60% of shunt operations. On univariable analysis, iodine/DuraPrep (OR 0.57, 95% CI 0.37-0.88, p = 0.02) and the use of an antibiotic-impregnated catheter in any segment of the shunt (or both) decreased infection risk (OR 0.53, 95% CI 0.34-0.82, p = 0.01). Iodine-based prep solutions (OR 0.56, 95% 0.36-0.86, p = 0.02) and the use of antibiotic-impregnated catheters (OR 0.52, 95% CI 0.34-0.81, p = 0.01) retained significance in the multivariable model, but no relationship between protocol use and infection risk was demonstrated in this baseline analysis.

CONCLUSIONS

The authors have demonstrated that children undergoing CSF shunt surgery at HCRNq sites share similar demographic characteristics with other large North American multicenter cohorts, with similar observed baseline infection rates and risk factors. Many centers have implemented standardized shunt infection prevention practices, but considerable practice variation remains. As such, there is an opportunity to decrease shunt infection rates in these centers through continued standardization of care.

One-Year Results of a Phase I/II Randomized, Double-Masked, Placebo-Controlled Study of Processed Amniotic Fluid Drops After PRK

PURPOSE

The aim of this study was to evaluate the 1-year outcomes of using processed amniotic fluid (pAF) postoperatively after photorefractive keratectomy (PRK).

METHODS

Sixty-one participants were randomized to receive either placebo or pAF drops. The drops were instilled 4 times daily for 1 week after PRK along with routine postoperative medications. The primary outcome measures included uncorrected visual acuity, topographic corneal irregularity measurement, and surface staining over 1 year.

RESULTS

A statistically significant difference in uncorrected distance visual acuity between the placebo and treatment groups was seen at 1 month post-PRK, with a visual advantage evident in the pAF group. A suggestive difference in corneal irregularity measurement was also seen between the placebo and treatment groups at 1 month postsurgery, with less irregularity noted in the pAF group. No differences in uncorrected distance visual acuity or corneal irregularity measurement were found at 3, 6, and 12 months. There was also no significant difference in corneal staining scores between the 2 groups at any of the measured time points.

CONCLUSIONS

This 1-year study evaluating the safety and efficacy of pAF as an additional postoperative topical medication after PRK demonstrated that pAF offered a mild visual advantage at 1 month post-PRK. There were no late adverse events, and the intervention proved safe at 1 year.

Morphological and ultrastructural investigation of the posterior atlanto-occipital membrane: Comparing children with Chiari malformation type I and controls

INTRODUCTION

The fibrous posterior atlanto-occipital membrane (PAOM) at the craniocervical junction is typically removed during decompression surgery for Chiari malformation type I (CM-I); however, its importance and ultrastructural architecture have not been investigated in children. We hypothesized that there are structural differences in the PAOM of patients with CM-I and those without.

METHODS

In this prospective study, blinded pathological analysis was performed on PAOM specimens from children who had surgery for CM-I and children who had surgery for posterior fossa tumors (controls). Clinical and radiographic data were collected. Statistical analysis included comparisons between the CM-I and control cohorts and correlations with imaging measures.

RESULTS

A total of 35 children (mean age at surgery 10.7 years; 94.3% white) with viable specimens for evaluation were enrolled: 24 with CM-I and 11 controls. There were no statistical demographic differences between the two cohorts. Four children had a family history of CM-I and five had a syndromic condition. The cohorts had similar measurements of tonsillar descent, syringomyelia, basion to C2, and condylar-to-C2 vertical axis (all p>0.05). The clival-axial angle was lower in patients with CM-I (138.1 vs. 149.3 degrees, p = 0.016). Morphologically, the PAOM demonstrated statistically higher proportions of disorganized architecture in patients with CM-I (75.0% vs. 36.4%, p = 0.012). There were no differences in PAOM fat, elastin, or collagen percentages overall and no differences in imaging or ultrastructural findings between male and female patients. Posterior fossa volume was lower in children with CM-I (163,234 mm3 vs. 218,305 mm3, p<0.001), a difference that persisted after normalizing for patient height (129.9 vs. 160.9, p = 0.028).

CONCLUSIONS

In patients with CM-I, the PAOM demonstrates disorganized architecture compared with that of control patients. This likely represents an anatomic adaptation in the presence of CM-I rather than a pathologic contribution.

Comparison of outcomes in the management of abdominal pseudocyst in children with shunted hydrocephalus: a Hydrocephalus Clinical Research Network study

OBJECTIVE

Abdominal pseudocyst (APC) can cause distal site failure in children with ventriculoperitoneal shunts and is specifically designated as an infection in Hydrocephalus Clinical Research Network (HCRN) protocols. Specific management and outcomes of children with APCs have not been reported in a multicenter study. In this study, the authors investigated the management and outcomes of APC in children with shunted hydrocephalus who were treated at centers in the HCRN.

METHODS

The HCRN Registry was queried to identify children < 18 years old with shunts who were diagnosed with an APC (i.e., a loculated abdominal fluid collection containing the peritoneal catheter with abdominal distention and/or displacement of peritoneal contents). The primary outcome was shunt failure after APC treatment. The primary variable was reimplantation of the distal catheter after pseudocyst treatment back into the peritoneum versus implantation in a nonperitoneal site. Other risk factors for shunt failure after APC treatment and variability in APC management were investigated.

RESULTS

Among 141 children from 14 centers who underwent first-time management of an APC over a 14-year period, the median time from previous shunt surgery to APC diagnosis was 3.8 months. Overall, 17.7% of children had a positive culture: APC cultures were positive in 14.2% and CSF cultures in 15.6%. Six other children underwent shunt revision without removal; all underwent reoperation within 1 month. There was no difference in shunt survival (log-rank test, p = 0.42) or number of subsequent revisions within 6, 12, or 24 months for shunts reimplanted in the abdomen versus those implanted in a nonperitoneal location. Nonperitoneal implantation was associated with more noninfectious revisions (42.3% vs 22.9%, p = 0.019), whereas infection was more common after reimplantation in the abdomen (25.7% vs 7.0%, p = 0.003). Univariable analysis demonstrated that younger age at APC diagnosis (8.3 vs 12.2 years, p = 0.006) and prior shunt procedure within 12 weeks of APC diagnosis (59.5% vs 40.5%, p = 0.012) were associated with shunt failure after APC treatment. Multivariable modeling confirmed that prior shunt surgery within 12 weeks of APC diagnosis was independently associated with failure (HR 1.79 [95% CI 1.04-3.07], p = 0.035).

CONCLUSIONS

In the HCRN, APCs in the setting of CSF shunts are usually managed with externalization. Shunt surgery within 12 weeks of APC diagnosis was associated with risk of failure after APC treatment. Although no differences were found in overall shunt failure rate, noninfectious shunt revisions were more common in the nonperitoneal distal catheter sites, and infection was a more common reason for failure after reimplantation of the shunt in the abdomen.

Treatment of hydrocephalus following posterior fossa tumor resection: a multicenter collaboration from the Hydrocephalus Clinical Research Network

OBJECTIVE

Persistent hydrocephalus following posterior fossa brain tumor (PFBT) resection is a common cause of morbidity in pediatric brain tumor patients, for which the optimal treatment is debated. The purpose of this study was to compare treatment outcomes between VPS and ETV in patients with persistent hydrocephalus following surgical resection of a PFBT.

METHODS

A post-hoc analysis was performed of the Hydrocephalus Clinical Research Network (HCRN) prospective observational study evaluating VPS and ETV for pediatric patients. Children who experienced hydrocephalus secondary to PFBT from 2008 to 2021 were included. Primary outcomes were VPS/ETV treatment failure and time-to-failure (TTF).

RESULTS

Among 241 patients, the VPS (183) and ETV (58) groups were similar in age, extent of tumor resection, and preoperative ETV Success Score. There was no difference in overall treatment failure between VPS and ETV (33.9% vs 31.0%, p = 0.751). However, mean TTF was shorter for ETV than VPS (0.45 years vs 1.30 years, p = 0.001). While major complication profiles were similar, compared to VPS, ETV patients had relatively higher incidence of minor CSF leak (10.3% vs. 1.1%, p = 0.003) and pseudomeningocele (12.1% vs 3.3%, p = 0.02). No ETV failures were identified beyond 3 years, while shunt failures occurred beyond 5 years. Shunt infections occurred in 5.5% of the VPS cohort.

CONCLUSIONS

ETV and VPS offer similar overall success rates for PFBT-related postoperative hydrocephalus. ETV failure occurs earlier, while susceptibility to VPS failure persists beyond 5 years. Tumor histology and grade may be considered when selecting the optimal means of CSF diversion.

Phase I/II randomized, double-masked, placebo-controlled study of processed amniotic fluid drops after PRK

PURPOSE

To evaluate the safety and efficacy of processed amniotic fluid (pAF) used postoperatively after photorefractive keratectomy (PRK).

SETTING

University of Utah, Moran Eye Center, Salt Lake City, Utah.

DESIGN

Randomized, double-masked, placebo-controlled prospective study.

METHODS

61 participants were randomized to receive either placebo or pAF drops, which were instilled 4 times per day for 1 week after PRK along with routine postoperative medications. The primary outcome measure was time to full re-epithelialization in days. Secondary measures included visual acuity at 30 days and postoperative pain scores during the first week.

RESULTS

There was no significant difference in time to re-epithelialization, with a median of 5 days for both groups. There were no difference in pain indicator scores during the first week and no difference in corneal staining scores at day 30 between the 2 groups. There were no adverse events.

CONCLUSIONS

This pilot study evaluating the safety and efficacy of pAF as an additional postoperative topical medication for PRK demonstrated that pAF did not improve the rate of epithelial healing after PRK. pAF may be safely studied in other ocular conditions to determine its effect on epithelial healing.

Safety and effectiveness of the assessment and treatment of idiopathic normal pressure hydrocephalus in the Adult Hydrocephalus Clinical Research Network

OBJECTIVE

The aim of this study was to describe the processes and outcomes associated with patients at five sites in the Adult Hydrocephalus Clinical Research Network (AHCRN) who had undergone evaluation and treatment for suspected idiopathic normal pressure hydrocephalus (iNPH) and had 1-year postoperative follow-up.

METHODS

Subjects with possible iNPH who had been prospectively enrolled in the AHCRN registry between November 19, 2014, and December 31, 2018, were evaluated by CSF drainage via either lumbar puncture or external lumbar drainage, consistent with recommendations of the international iNPH guidelines. Standardized clinical evaluations of gait, cognition, urinary symptoms, depression, and functional outcomes were conducted at baseline, before and after CSF drainage, and at 4-month intervals after shunt surgery. Complications of CSF drainage and shunt surgery were recorded.

RESULTS

Seventy-four percent (424/570) of patients with possible iNPH had CSF drainage, and 46% of them (193/424) underwent shunt surgery. The mean change in gait velocity with CSF drainage was 0.18 m/sec in patients who underwent shunt surgery versus 0.08 m/sec in patients who did not. For shunt surgery patients, gait velocity increased by 54% from 0.67 m/sec before CSF drainage to 0.96 m/sec 8-12 months after surgery, and 80% of patients had an increase of at least 0.1 m/sec by the first postoperative visit. Evaluation of cognition, urinary symptoms, depression, and functional outcomes also revealed improvement after shunt surgery. Of 193 patients who had undergone shunt surgery, 176 (91%) had no complications and 17 (9%) had 28 complications. Eleven patients (6%) had 14 serious complications that resulted in the need for surgery or an extended hospital stay. The 30-day reoperation rate was 3%.

CONCLUSIONS

Using criteria recommended by the international iNPH guidelines, the authors found that evaluation and treatment of iNPH are safe and effective. Testing with CSF drainage and treatment with shunt surgery are associated with a high rate of sustained improvement and a low rate of complications for iNPH in the 1st year after shunt surgery. Patients who had undergone shunt surgery for iNPH experienced improvement in gait, cognitive function, bladder symptoms, depression, and functional outcome measures. Gait velocity, which is an easily measured, objective, continuous variable, should be used as a standard outcome measure to test a patient's response to CSF drainage and shunt surgery in iNPH.

Endoscopic third ventriculostomy in previously shunt-treated patients

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is an option for treatment of hydrocephalus, including for patients who have a history of previous treatment with CSF shunt insertion. The purpose of this study was to report the success of postshunt ETV by using data from a multicenter prospective registry.

METHODS

Prospectively collected data in the Hydrocephalus Clinical Research Network (HCRN) Core Data Project (i.e., HCRN Registry) were reviewed. Children who underwent ETV between 2008 and 2019 and had a history of previous treatment with a CSF shunt were included. A Kaplan-Meier survival curve was created for the primary outcome: time from postshunt ETV to subsequent CSF shunt placement or revision. Univariable Cox proportional hazards models were created to evaluate for an association between clinical and demographic variables and subsequent shunt surgery. Postshunt ETV complications were also identified and categorized.

RESULTS

A total of 203 children were included: 57% male and 43% female; 74% White, 23% Black, and 4% other race. The most common hydrocephalus etiologies were postintraventricular hemorrhage secondary to prematurity (56, 28%) and aqueductal stenosis (42, 21%). The ETV Success Score ranged from 10 to 80. The median patient age was 4.1 years. The overall success of postshunt ETV at 6 months was 41%. Only the surgeon's report of a clear view of the basilar artery was associated with a lower likelihood of postshunt ETV failure (HR 0.43, 95% CI 0.23-0.82, p = 0.009). None of the following variables were associated with postshunt ETV success: age at the time of postshunt ETV, etiology of hydrocephalus, sex, race, ventricle size, number of previous shunt operations, ETV performed at time of shunt infection, and use of external ventricular drainage. Overall, complications were reported in 22% of patients, with CSF leak (8.6%) being the most common complication.

CONCLUSIONS

Postshunt ETV was successful in treating hydrocephalus, without subsequent need for a CSF shunt, in 41% of patients, with a clear view of the basilar artery being the only variable significantly associated with success. Complications occurred in 22% of patients. ETV is an option for treatment of hydrocephalus in children who have previously undergone shunt placement, but with a lower than expected likelihood of success.

Assessing how routes to diagnosis vary by the age of patients with cancer: a nationwide register-based cohort study in Denmark

BACKGROUND

Older patients with cancer have poorer prognosis compared to younger patients. Moreover, prognosis is related to how cancer is identified, and where in the healthcare system patients present, i.e. routes to diagnosis (RtD). We investigated whether RtD varied by patients' age.

METHODS

This population-based national cohort study used Danish registry data. Patients were categorized into age groups and eight mutually exclusive RtD. We employed multinomial logistic regressions adjusted for sex, region, diagnosis year, cohabitation, education, income, immigration status and comorbidities. Screened and non-screened patients were analysed separately.

RESULTS

The study included 137,876 patients. Both younger and older patients with cancer were less likely to get diagnosed after a cancer patient pathways referral from primary care physician compared to middle-aged patients. Older patients were more likely to get diagnosed via unplanned admission, death certificate only, and outpatient admission compared to younger patients. The patterns were similar across comorbidity levels.

CONCLUSIONS

RtD varied by age groups, and middle-aged patients were the most likely to get diagnosed after cancer patient pathways with referral from primary care. Emphasis should be put on raising clinicians' awareness of cancer being the underlying cause of symptoms in both younger patients and in older patients.

Endoscopic third ventriculostomy revision after failure of initial endoscopic third ventriculostomy and choroid plexus cauterization

OBJECTIVE

Primary treatment of hydrocephalus with endoscopic third ventriculostomy (ETV) and choroid plexus cauterization (CPC) is well described in the neurosurgical literature, with wide reported ranges of success and complication rates. The purpose of this study was to describe the safety and efficacy of ETV revision after initial ETV+CPC failure.

METHODS

Prospectively collected data in the Hydrocephalus Clinical Research Network Core Data Project registry were reviewed. Children who underwent ETV+CPC as the initial treatment for hydrocephalus between 2013 and 2019 and in whom the initial ETV+CPC was completed (i.e., not abandoned) were included. Log-rank survival analysis (the primary analysis) was used to compare time to failure (defined as any other surgical treatment for hydrocephalus or death related to hydrocephalus) of initial ETV+CPC versus that of ETV revision by using random-effects modeling to account for the inclusion of patients in both the initial and revision groups. Secondary analysis compared ETV revision to shunt placement after failure of initial ETV+CPC by using the log-rank test, as well as shunt failure after ETV+CPC to that after ETV revision. Cox regression analysis was used to identify predictors of failure among children treated with ETV revision.

RESULTS

The authors identified 521 ETV+CPC procedures that met their inclusion criteria. Ninety-one children underwent ETV revision after ETV+CPC failure. ETV revision had a lower 1-year success rate than initial ETV+CPC (29.5% vs 45%, p < 0.001). ETV revision after initial ETV+CPC failure had a lower success rate than shunting (29.5% vs 77.8%, p < 0.001). Shunt survival after initial ETV+CPC failure was not significantly different from shunt survival after ETV revision failure (p = 0.963). Complication rates were similar for all examined surgical procedures (initial ETV+CPC, ETV revision, ventriculoperitoneal shunt [VPS] placement after ETV+CPC, and VPS placement after ETV revision). Only young age was predictive of ETV revision failure (p = 0.02).

CONCLUSIONS

ETV revision had a significantly lower 1-year success rate than initial ETV+CPC and VPS placement after ETV+CPC. Complication rates were similar for all studied procedures. Younger age, but not time since initial ETV+CPC, was a risk factor for ETV revision failure.

OP0037 USE OF PRIMARY HEALTHCARE AND RADIOLOGICAL IMAGING PRECEDING A DIAGNOSIS OF RHEUMATOID ARTHRITIS: A DANISH NATIONWIDE COHORT STUDY

Background

Focus on early diagnosis and treatment initiation is key in rheumatoid arthritis (RA) to prevent permanent joint damage and systemic manifestations. Increased use of healthcare services before an RA diagnosis can be seen as a proxy for symptom presentation and the actions taken by healthcare professionals, and thus indicate an opportunity for earlier diagnosis. However, little is known about where and when people use healthcare services before an RA diagnosis.

Objectives

To explore the pattern in use of healthcare services during the 12 months preceding a diagnosis of RA in Denmark.

Methods

We conducted a population-based cohort study using data from Danish national registries. For every patient diagnosed with RA in 2014-2018 we matched ten reference persons from the Danish general population without RA, listed in the same general practice and with same age and sex. Healthcare use was defined as: daytime face to face contacts to general practice, contacts to private practicing physiotherapists.

We estimated the monthly healthcare use for patients with RA and reference persons in the 12 months preceding the diagnosis, and we compared their healthcare use by incidence rate ratios (IRR) for each month, adjusted for sociodemographic characteristics and comorbidity.

Results

7,427 patients with RA and 74,270 reference persons were included in the study. The median age was 62 years (interquartile interval (IQI): 51-71), and 65% were women. Patients with RA had an average of 0.5 contacts per month in general practice from 12 months until six months prior to the diagnosis (Figure 1); this number increased from six months before the diagnosis to an average of one contact in the last month before the diagnosis. Reference persons had an average of 0.4 contacts per months throughout the entire study period. Compared to their references, patients with RA had statistically significantly more contacts during all 12 months before the diagnosis date; IRR increased from 1.25 (95% CI: 1.19-1.30) to 2.63 (2.55-2.71) during the study period.

Patients with RA also had statstistically significantly more contacts to physiotherapists compared to their references throughout the entire study period, and increasing contact rates from eight months before the diagnosis. This was primarily driven by more contacts in women with RA compared to their references.

Conclusion

Patients with RA had more contacts to general practice and physiotherapists in all 12 months preceding the RA diagnosis compared to references and these contact rates increased further the last six to eight months in patients with RA. This indicates symptom presentation for several months before the RA is diagnosed, and it indicates that a window of opportunity exists to expedite referral to specialist care and the diagnosis of RA.

Disclosure of Interests

None declared.

The Hydrocephalus Clinical Research Network quality improvement initiative: the role of antibiotic-impregnated catheters and vancomycin wound irrigation

OBJECTIVE

Two previous Hydrocephalus Clinical Research Network (HCRN) studies have demonstrated that compliance with a standardized CSF shunt infection protocol reduces shunt infections. In this third iteration, a simplified protocol consisting of 5 steps was implemented. This analysis provides an updated evaluation of protocol compliance and evaluates modifiable shunt infection risk factors.

METHODS

The new simplified protocol was implemented at HCRN centers on November 1, 2016, for all shunt procedures, excluding external ventricular drains, ventricular reservoirs, and subgaleal shunts. Procedures performed through December 31, 2019, were included (38 months). Compliance with the protocol, use of antibiotic-impregnated catheters (AICs), and other variables of interest were collected at the index operation. Outcome events for a minimum of 6 months postoperatively were recorded. The definition of infection was unchanged from the authors' previous report.

RESULTS

A total of 4913 procedures were performed at 13 HCRN centers. The overall infection rate was 5.1%. Surgeons were compliant with all 5 steps of the protocol in 79.4% of procedures. The infection rate for the protocol alone was 8.1% and dropped to 4.9% when AICs were added. Multivariate analysis identified having ≥ 2 complex chronic conditions (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.26-2.44, p = 0.01) and a history of prior shunt surgery within 12 weeks (OR 1.84, 95% CI 1.37-2.47, p < 0.01) as independent risk factors for shunt infection. The use of AICs (OR 0.70, 95% CI 0.50-0.97, p = 0.05) and vancomycin irrigation (OR 0.36, 95% CI 0.21-0.62, p < 0.01) were identified as independent factors protective against shunt infection.

CONCLUSIONS

The authors report the third iteration of their quality improvement protocol to reduce the risk of shunt infection. Compliance with the protocol was high. These updated data suggest that the incorporation of AICs is an important, modifiable infection prevention measure. Vancomycin irrigation was also identified as a protective factor but requires further study to better understand its role in preventing shunt infection.

Anterior versus posterior entry site for ventriculoperitoneal shunt insertion: a randomized controlled trial by the Hydrocephalus Clinical Research Network

OBJECTIVE

The primary objective of this trial was to determine if shunt entry site affects the risk of shunt failure.

METHODS

The authors performed a parallel-design randomized controlled trial with an equal allocation of patients who received shunt placement via the anterior entry site and patients who received shunt placement via the posterior entry site. All patients were children with symptoms or signs of hydrocephalus and ventriculomegaly. Patients were ineligible if they had a prior history of shunt insertion. Patients received a ventriculoperitoneal shunt after randomization; randomization was stratified by surgeon. The primary outcome was shunt failure. The planned minimum follow-up was 18 months. The trial was designed to achieve high power to detect a 10% or greater absolute difference in the shunt failure rate at 1 year. An independent, blinded adjudication committee determined eligibility and the primary outcome. The study was conducted by the Hydrocephalus Clinical Research Network.

RESULTS

The study randomized 467 pediatric patients at 14 tertiary care pediatric hospitals in North America from April 2015 to January 2019. The adjudication committee, blinded to intervention, excluded 7 patients in each group for not meeting the study inclusion criteria. For the primary analysis, there were 229 patients in the posterior group and 224 patients in the anterior group. The median patient age was 1.3 months, and the most common etiologies of hydrocephalus were postintraventricular hemorrhage secondary to prematurity (32.7%), myelomeningocele (16.8%), and aqueductal stenosis (10.8%). There was no significant difference in the time to shunt failure between the entry sites (log-rank test, stratified by age < 6 months and ≥ 6 months; p = 0.061). The hazard ratio (HR) of a posterior shunt relative to an anterior shunt was calculated using a univariable Cox regression model and was nonsignificant (HR 1.35, 95% CI, 0.98-1.85; p = 0.062). No significant difference was found between entry sites for the surgery duration, number of ventricular catheter passes, ventricular catheter location, and hospital length of stay. There were no significant differences between entry sites for intraoperative complications, postoperative CSF leaks, pseudomeningoceles, shunt infections, skull fractures, postoperative seizures, new-onset epilepsy, or intracranial hemorrhages.

CONCLUSIONS

This randomized controlled trial comparing the anterior and posterior shunt entry sites has demonstrated no significant difference in the time to shunt failure. Anterior and posterior entry site surgeries were found to have similar outcomes and similar complication rates.

Distribution of natural and anthropogenic radionuclides in sediments from the Vefsnfjord, Norway

Areas in central Norway were heavily contaminated with fallout from the Chernobyl accident in 1986. In this study, we assess ¹³⁷Cs in surface sediments and sediment cores collected in the Vefsnfjord in Nordland county. Concentrations of ¹³⁷Cs in surface sediments ranged from 159 to 191 Bq kg^-1 dry weight (d.w.). Sub-surface peaks of ¹³⁷Cs were observed in all cores, with a maximum concentration of 432 Bq kg^-1 d.w. Given that little is known about the distribution of naturally occurring radionuclides in Norwegian fjords and coastal areas, a better understanding of the total burden of radioactivity is important for the Norwegian fishing and aquaculture industries. Therefore, analyses of the natural radionuclides ⁴⁰K, ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb were included in the study. Analyses of total sulphur (TS), total carbon (TC), total organic carbon (TOC) and grain size distribution have been performed to provide a sedimentologic context for interpreting the radionuclide results.

Geochronology of sediment cores from the Vefsnfjord, Norway

The sedimentary environment is a repository and carrier for a variety of pollutants, and sediment transport from land to coastal areas is an important environmental process. In the present study, we use ²¹⁰Pb/²²⁶Ra and ¹³⁷Cs in sediment cores to assess sediment supply rates at four sites within the Vefsnfjord in Nordland county, Norway. This area was highly affected by fallout from the Chernobyl accident in 1986 and inventories of ¹³⁷Cs in the fjord are much higher than in many other Norwegian fjords. Sedimentation rates between 0.042 and 0.25 g cm^-2 y^-1 (0.060 and 0.38 cm y^-1) were determined using a combination of the Constant Rate of Supply (CRS) and Constant Flux:Constant Sedimentation rate (CF:CS) models. Well-defined ¹³⁷Cs concentration peaks were used as a supplementary tool to the ²¹⁰Pb dating methods.

Longitudinal CSF Iron Pathway Proteins in Posthemorrhagic Hydrocephalus: Associations with Ventricle Size and Neurodevelopmental Outcomes

OBJECTIVE

Iron has been implicated in the pathogenesis of brain injury and hydrocephalus after preterm germinal matrix hemorrhage-intraventricular hemorrhage, however, it is unknown how external or endogenous intraventricular clearance of iron pathway proteins affect the outcome in this group.

METHODS

This prospective multicenter cohort included patients with posthemorrhagic hydrocephalus (PHH) who underwent (1) temporary and permanent cerebrospinal fluid (CSF) diversion and (2) Bayley Scales of Infant Development-III testing around 2 years of age. CSF proteins in the iron handling pathway were analyzed longitudinally and compared to ventricle size and neurodevelopmental outcomes.

RESULTS

Thirty-seven patients met inclusion criteria with a median estimated gestational age at birth of 25 weeks; 65% were boys. Ventricular CSF levels of hemoglobin, iron, total bilirubin, and ferritin decreased between temporary and permanent CSF diversion with no change in CSF levels of ceruloplasmin, transferrin, haptoglobin, and hepcidin. There was an increase in CSF hemopexin during this interval. Larger ventricle size at permanent CSF diversion was associated with elevated CSF ferritin (p = 0.015) and decreased CSF hemopexin (p = 0.007). CSF levels of proteins at temporary CSF diversion were not associated with outcome, however, higher CSF transferrin at permanent CSF diversion was associated with improved cognitive outcome (p = 0.015). Importantly, longitudinal change in CSF iron pathway proteins, ferritin (decrease), and transferrin (increase) were associated with improved cognitive (p = 0.04) and motor (p = 0.03) scores and improved cognitive (p = 0.04), language (p = 0.035), and motor (p = 0.008) scores, respectively.

INTERPRETATION

Longitudinal changes in CSF transferrin (increase) and ferritin (decrease) are associated with improved neurodevelopmental outcomes in neonatal PHH, with implications for understanding the pathogenesis of poor outcomes in PHH. ANN NEUROL 2021;90:217-226.

OP0159-HPR IMPACT OF NON-PHARMACOLOGICAL INTERVENTIONS TARGETING SLEEP DISTURBANCES OR DISORDERS IN PATIENTS WITH INFLAMMATORY ARTHRITIS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMISED TRIALS

Background:

Patients with inflammatory arthritis (IA) often present limitations in daily life due to unpredictability, severity and chronicity of the disease, reduced functional ability and health-related quality of life. Moreover, sleep disturbances or disorders have been reported in up to 40-90% of patients with IA [1-3]. Sleep disturbances are further associated with pain, fatigue, mental well-being and disease activity [4]. As chronic us of hypnotic drugs are associated with tolerance and side effects, there is growing interest in non-pharmacological management to improve sleep.

Objectives:

With a systematic review and meta-analysis, our primary objective was to evaluate the evidence of non-pharmacological interventions targeting sleep in patients with IA. Primary outcome was sleep domains, while secondary objectives were based on the core outcome domains for IA trials and harms.

Methods:

Following protocol closure, a systematic search was undertaken in MEDLINE, CENTRAL, PsycINFO, CINAHL, ClinicalTrials.gov, ACR and EULAR in September 2020. Eligible studies were randomised trials with adults with IA and concomitant sleep disturbances or disorders, comparing a non-pharmacological intervention targeting sleep disturbances or disorders to another non-pharmacological intervention, a pharmacological intervention or standard care. Screening of titles, abstracts, and subsequent full text assessment were conducted independently by two reviewers using the Covidence tool. Randomisation, blinding, and adequacy of analyses was assessed using the Cochrane’s RoB tool and the overall quality of evidence was rated using GRADE methodology. Disagreements were resolved at consensus meetings with last authors. Effect sizes for continuous outcomes were based on the standardised mean difference (SMD), combined using standard random-effects meta-analysis (all with 95% CIs).

Results:

Six trials (308 patients) were included in the quantitative synthesis. Two trials included patients with the sleep disorder insomnia and the remaining four trials included patients with sleep disturbances. Sleep domains were measured with Pittsburgh Sleep Quality Index (PSQI) or Insomnia Severity index (ISI). Three trials reported improvement on sleep following foot reflexology, auricular plaster therapy, and exercise. The overall meta-analysis presented in the figure of forest plot for self-reported sleep suggests that non-pharmacological interventions have a potentially large effect size of -0.80 (95% CI, -1.33 to -0.28) on sleep. However, the quality of the evidence was assessed as corresponding to low, given that the body of the evidence was rated down twice, due to serious study limitations and inconsistency.

Conclusion:

Although the effect of non-pharmacological interventions targeting sleep disturbances or the sleep disorder insomnia was statistically highly significant, the implication for clinical practice is questionable because of the overall quality evidence. None of the core outcomes used in contemporary IA trials have indicated clinical benefit in favour of non-pharmacological interventions targeting sleep disturbances or disorders.

In conclusion, more rigorous research on non-pharmacological management of sleep disturbances and disorders is urgently needed, also aimed at specific sleep disorders, in order to fully reveal the clinical utility of these novel treatment options. At this point, non-pharmacological treatment of sleep disturbances or disorders is promising and potentially highly effective, and may have the potential to persistently decrease the symptom burden and increase the quality of life of patients with IA.

References:

[1]Li et al., Psychol Health Med. 2019 Sep;24(8):911-924

[2]Haugeberg et al., Arthritis Res Ther. 2020 Aug 26;22(1):198

[3]Wali et al., J Clin Sleep Med. 2020 Feb 15;16(2):259-265

[4]Løppenthin et al., Clin Rheumatol. 2015 Dec;34(12):2029-39

Disclosure of Interests:

Kristine Marie Latocha: None declared, Katrine Løppenthin: None declared, Safa Al-Bazy: None declared, Tannie Albrechtsen: None declared, Helle Jensen: None declared, Mikkel Østergaard Speakers bureau: Abbvie, Celgene, Eli-Lilly, Janssen, Novartis, Pfizer, Roche, Sanofi and UCB, Consultant of: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Grant/research support from: Abbvie, BMS, Merck, Celgene, Novartis, Poul Jennum: None declared, Bente Appel Esbensen: None declared, Robin Christensen: None declared

Treatment strategies for hydrocephalus related to Dandy-Walker syndrome: evaluating procedure selection and success within the Hydrocephalus Clinical Research Network

OBJECTIVE

Treating Dandy-Walker syndrome-related hydrocephalus (DWSH) involves either a CSF shunt-based or endoscopic third ventriculostomy (ETV)-based procedure. However, comparative investigations are lacking. This study aimed to compare shunt-based and ETV-based treatment strategies utilizing archival data from the Hydrocephalus Clinical Research Network (HCRN) registry.

METHODS

A retrospective review of prospectively collected and maintained data on children with DWSH, available from the HCRN registry (14 sites, 2008-2018), was performed. The primary outcome was revision-free survival of the initial surgical intervention. The primary exposure was either shunt-based (i.e., cystoperitoneal shunt [CPS], ventriculoperitoneal shunt [VPS], and/or dual-compartment) or ETV-based (i.e., ETV alone or with choroid plexus cauterization [CPC]) initial surgical treatment. Primary analysis included multivariable Cox proportional hazards models.

RESULTS

Of 8400 HCRN patients, 151 (1.8%) had DWSH. Among these, the 102 patients who underwent shunt placement (79 VPSs, 16 CPSs, 3 other, and 4 multiple proximal catheter) were younger (6.6 vs 18.8 months, p < 0.001) and more frequently had 1 or more comorbidities (37.3% vs 14.3%, p = 0.005) than the 49 ETV-treated children (28 ETV-CPC). Fifty percent of the shunt-based and 51% of the ETV-based treatments failed. Notably, 100% (4/4) of the dual-compartment shunts failed. Adjusting for age, baseline ventricular size, and comorbidities, ETV-based treatment was not significantly associated with earlier failure compared with shunt-based treatment (HR for failure 1.32, 95% CI 0.77-2.26; p = 0.321). Complication rates were low: 4.9% and 6.1% (p = 0.715) for shunt- and ETV-based procedures, respectively. There was no difference in survival between ETV-CPC- and ETV-based treatment when adjusting for age (HR for failure 0.86, 95% CI 0.29-2.55, p = 0.783).

CONCLUSIONS

In this North American, multicenter, prospective database review, shunt-based and ETV-based primary treatment strategies of DWSH appear similarly durable. Pediatric neurosurgeons can reasonably consider ETV-based initial treatment given the similar durability and the low complication rate. However, given the observational nature of this study, the treating surgeon might need to consider subgroups that were too small for a separate analysis. Very young children with comorbidities were more commonly treated with shunts, and older children with fewer comorbidities were offered ETV-based treatment. Future studies may determine preoperative characteristics associated with ETV treatment success in this population.

Nursing teamwork in the care of older people: A mixed methods study

Healthcare is increasingly complex and requires the ability to adapt to changing demands. Teamwork is essential to delivering high quality care and is central to nursing. The aims of this study were to identify the processes that underpin nursing teamwork and how these affect the care of older people, identify the relationship between perceived teamwork and perceived quality of care, and explore in depth the experience of working in nursing teams. The study was carried out in three older people's wards in a London teaching hospital. Nurses and healthcare assistants completed questionnaires (n = 65) on known dynamics of teamwork (using the Nursing Teamwork Survey) together with ratings of organisational quality (using an adapted AHRQ HSPS scale). A sample (n = 22; 34%) was then interviewed about their perceptions of care, teamwork and how good outcomes are delivered in everyday work. Results showed that many care difficulties were routinely encountered, and confirmed the importance of teamwork (e.g. shared mental models of tasks and team roles and responsibilities, supported by leadership) in adapting to challenges. Perceived quality of teamwork was positively related to perceived quality of care. Work system variability and the external environment influenced teamwork, and confirmed the importance of team adaptive capacity. The CARE model shows the centrality of teamwork in adapting to variable demand and capacity to deliver care processes, and the influence of broader system factors on teamworking.

P2844Novel temperature guided irrigated ablation catheter: reproducibility of procedural efficiencies and acute success to isolate the pulmonary veins from two multicenter, feasibility studies

Background/Introduction

The novel catheter with 6 thermocouples for real-time temperature monitoring during irrigated radiofrequency ablation was designed to potentially enhance safety and effectiveness of the Smart Touch Surround Flow (STSF) catheter by incorporating real-time temperature sensing. A supplementary, novel algorithm was developed to modulate power to maintain target temperature during high power/short duration ablation (90W, 4s).

Purpose

This sub-analysis was performed to examine consistency and reproducibility of the procedural efficiencies and acute success of the novel catheter with optimized temperature control and microelectrodes in treating paroxysmal atrial fibrillation (PAF) across multiple sites from two initial feasibility studies, in standard (QMODE) and high power/short duration (QMODE+) temperature-control ablation modes.

Methods

The QDOT-MICRO (QMODE, NCT02944968; N=42) and QDOT-FAST (QMODE+, NCT03459196; N=52) studies were both prospective, non-randomized multi-center, clinical investigations completed across 6 and 7 centers, respectively, in Europe. Procedural efficiencies and acute success (PVI via entrance block) was examined across sites within the study.

Results

In the QDOT-MICRO study, median procedure time (105–155 min), RF ablation time (27.7–39.5 min), and fluoroscopy times (2.2–8 min) during QMODE ablation were similar across the 6 sites. In QMODE+ ablation, median procedure time, RF ablation time, and fluoroscopy times all fall within (84–134 min), (4.8–9.7 min) and (1.1–9.6 min), respectively, across the 7 sites. Fluid delivery by the study catheter was low in both studies: QDOT-MICRO 547±278mL (mean ± SD); QDOT-FAST 382±299. mL (mean ± SD); which is 39.1 and 57.4% lower, respectively, than reported in the SMART SF trial. Esophageal temperature probe was used in the majority of patients (30/42 for QDOT MICRO and 51/52 for QDOT-FAST). Acute PVI was successful in 100% of patients in both studies with no deaths or unanticipated AEs.

Conclusion(s)

In both feasibility studies, procedural efficiencies were reproducible across study sites in both QMODE and QMODE+, with 100% acute success and good safety outcomes. Efficiencies are likely to improve with further experience. These results need to be confirmed in larger trials.

Acknowledgement/Funding

Both Studies are Company Sponsored Studies funded by Biosense Webster, Inc.

Rural-Urban Variation in Time to Diagnosis and Treatment of Colorectal or Breast Cancer in Victoria, Australia

Background: Rural-urban disparities in cancer outcomes are found in many countries, though these vary by cancer type. In Victoria, Australia, survival is poorer for rural patients with colorectal cancer, but not breast cancer. Delayed diagnosis and treatment may contribute to disparities, but previous studies have not compared the timeliness of rural and urban pathways to treatment of these common cancers. Aim: We investigated whether time to diagnosis and treatment differed for rural and urban patients with colorectal or breast cancer in Victoria, Australia. Methods: Population-based, cross-sectional surveys examining events and dates on the pathway to treatment completed by patients aged ≥ 40 and approached within six months of diagnosis, their general practitioner (GP) and specialist. Data were collected from 2013 to 2014 as part of the International Cancer Benchmarking Partnership, Module 4. Six intervals were explored: patient (symptom to presentation), primary care (presentation to referral), diagnostic (presentation/screening to diagnosis), treatment (diagnosis to treatment), health system (presentation to treatment) and total intervals (symptom/screening to treatment). Rural-urban differences were examined for each cancer using quantile regression (50th, 75th and 90th percentiles) models including age, gender, health insurance and socioeconomic status. Results: 433 colorectal (48% rural) and 489 breast (42% rural) patients, 621 GPs and 370 specialists completed surveys. Compared with urban patients, symptomatic colorectal cancer patients from rural areas had a significantly longer total interval at all percentiles: 50th (18 days longer, 95% confidence interval (CI): 9-27), 75th (53, 95% CI: 47-59) 90th (44, 95% CI: 40-48). These patients also had longer health system intervals, ranging 7-85 days longer. This appeared mostly due to longer diagnostic intervals (range: 6-54 days longer). Results were similar when including screen-detected cases. In contrast, breast cancer intervals were similar for rural and urban patients, except the patient interval, which was shorter for rural patients. Conclusion: Consistent with variation in survival, we found longer total and diagnostic intervals for rural compared with urban patients with colorectal cancer, but not breast cancer. The lack of rural-urban differences observed for breast cancer suggest that inequities in the timeliness of colorectal cancer pathways can be ameliorated, and may improve clinical outcomes. Indeed, based on previous research, delays observed in this study could result in stage progression and hence reduced survival. From our results, interventions targeting the time from presentation to colorectal cancer diagnosis in rural populations should be pursued. Countries seeking to understand cancer disparities in their local context may also consider using a pathways approach to identify possible targets for policy intervention.

Insights into the genetic architecture of morphological traits in two passerine bird species

Knowledge about the underlying genetic architecture of phenotypic traits is needed to understand and predict evolutionary dynamics. The number of causal loci, magnitude of the effects and location in the genome are, however, still largely unknown. Here, we use genome-wide single-nucleotide polymorphism (SNP) data from two large-scale data sets on house sparrows and collared flycatchers to examine the genetic architecture of different morphological traits (tarsus length, wing length, body mass, bill depth, bill length, total and visible badge size and white wing patches). Genomic heritabilities were estimated using relatedness calculated from SNPs. The proportion of variance captured by the SNPs (SNP-based heritability) was lower in house sparrows compared with collared flycatchers, as expected given marker density (6348 SNPs in house sparrows versus 38 689 SNPs in collared flycatchers). Indeed, after downsampling to similar SNP density and sample size, this estimate was no longer markedly different between species. Chromosome-partitioning analyses demonstrated that the proportion of variance explained by each chromosome was significantly positively related to the chromosome size for some traits and, generally, that larger chromosomes tended to explain proportionally more variation than smaller chromosomes. Finally, we found two genome-wide significant associations with very small-effect sizes. One SNP on chromosome 20 was associated with bill length in house sparrows and explained 1.2% of phenotypic variation (V_P), and one SNP on chromosome 4 was associated with tarsus length in collared flycatchers (3% of V_P). Although we cannot exclude the possibility of undetected large-effect loci, our results indicate a polygenic basis for morphological traits.

Assertive Interventions for First Episode Psychoses: The Danish Experience

Early Intervention services with team-based intensive case management and family involvement are superior to standard treatment in reducing psychotic and negative symptoms and comorbid substance abuse and improving social functioning and user satisfaction. The results of the OPUS-trial will be presented together with meta-analyses based on similar trials. The implementation of OPUS all over Denmark will be presented together with the Danish OPUS-fidelity study. Specialized elements are being are being developed such as inclusion of new methods in CBT for psychotic and negative symptoms, neurocognitive and social cognitive training programs, interventions for supported employment and focus on physical health. Results of long term follow-up studies indicate that the prognosis of first episode psychosis is very diverse with the extremes represented by one group being well functioning and able to quit medication without relapse; and another group having a long term chronic course of illness with a need for support to maintain daily activities. The Danish TAILOR-trial–testing dose reduction versus maintenance therapy will be presented. It will be of immense value to be able to intervene in risk groups identified in the premorbid phase, and there are few examples of ongoing trial for children of parent with schizophrenia and bipolar disorder.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Sex-linked inheritance, genetic correlations and sexual dimorphism in three melanin-based colour traits in the barn owl

Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.

A homozygous mutation in a consanguineous family consolidates the role of ALDH1A3 in autosomal recessive microphthalmia

Anomalies of eye development can lead to the rare eye malformations microphthalmia and anophthalmia (small or absent ocular globes), which are genetically very heterogeneous. Several genes have been associated with microphthalmia and anophthalmia, and exome sequencing has contributed to the identification of new genes. Very recently, homozygous variations within ALDH1A3 have been associated with autosomal recessive microphthalmia with or without cysts or coloboma, and with variable subphenotypes of developmental delay/autism spectrum disorder in eight families. In a consanguineous family where three of the five siblings were affected with microphthalmia/coloboma, we identified a novel homozygous missense mutation in ALDH1A3 using exome sequencing. Of the three affected siblings, one had intellectual disability and one had intellectual disability and autism, while the last one presented with normal development. This study contributes further to the description of the clinical spectrum associated with ALDH1A3 mutations, and illustrates the interfamilial clinical variation observed in individuals with ALDH1A3 mutations.

Quantification of activity by alpha-camera imaging and small-scale dosimetry within ovarian carcinoma micrometastases treated with targeted alpha therapy

Targeted alpha therapy (TAT) a promising treatment for small, residual, and micrometastatic diseases has questionable efficacy against malignant lesions larger than the α-particle range, and likely requires favorable intratumoral activity distribution. Here, we characterized and quantified the activity distribution of an alpha-particle emitter radiolabelled antibody within >100-µm micrometastases in a murine ovarian carcinoma model. Nude mice bearing ovarian micrometastases were injected intra-peritoneally with 211At-MX35 (total injected activity 6 MBq, specific activity 650 MBq/mg). Animals were sacrificed at several time points, and peritoneal samples were excised and prepared for alpha-camera imaging. Spatial and temporal activity distributions within micrometastases were derived and used for small-scale dosimetry. We observed two activity distribution patterns: uniform distribution and high stable uptake (>100% IA/g at all time points) in micrometastases with no visible stromal compartment, and radial distribution (high activity on the edge and poor uptake in the core) in tumor cell lobules surrounded by fibroblasts. Activity distributions over time were characterized by a peak (140% IA/g at 4 h) in the outer tumor layer and a sharp drop beyond a depth of 50 µm. Small-scale dosimetry was performed on a multi-cellular micrometastasis model, using time-integrated activities derived from the experimental data. With injected activity of 400 kBq, tumors exhibiting uniform activity distribution received <25 Gy (EUD=13 Gy), whereas tumors presenting radial activity distribution received mean absorbed doses of <8 Gy (EUD=5 Gy). These results provide new insight into important aspects of TAT, and may explain why micrometastases >100 µm might not be effectively treated by the examined regimen.

Dietary ontogeny and niche shift to piscivory in lacustrine brown trout Salmo trutta revealed by stomach content and stable isotope analyses

The feeding ecology and ontogeny of a large size range of brown trout Salmo trutta in Lake Fyresvatnet, southern Norway, were examined by stomach content and stable isotope analyses. According to the stomach contents, the S. trutta changed their diet at c. 30 cm total length (L(T) ). The smaller size classes fed on benthic invertebrates and surface insects, whereas larger S. trutta (>30 cm) fed mainly on whitefish Coregonus lavaretus. A similar, but more gradual shift to piscivory in the size range 25-30 cm was found when using the stable isotope mixing model SIAR to reveal dietary ontogeny. The δ¹³C isotopic signature confirmed that S. trutta independent of size predominantly relied upon benthic energy sources, suggesting that the littoral zone was the primary foraging habitat for both invertebrate and piscivorous feeders. The δ¹⁵N values and trophic position increased with predator length, ranging from an average of 3·60 for small-sized S. trutta (<15 cm) to 4·15 for large-sized fish (>35 cm). The S. trutta exhibited a relatively slow growth rate during the predominant invertebrate feeding stages up to 7 years of age and 28 cm L(T) , whereas fish above this size and age displayed a rapid growth rate of 9-11 cm year⁻¹, demonstrating the profitability of piscivorous feeding.

Search for the standard model Higgs boson in the decay channel H→ZZ→4ℓ in pp collisions at √s=7 TeV

A search for a Higgs boson in the four-lepton decay channel H→ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range of 110<m(H)<600 GeV. The analysis uses data corresponding to an integrated luminosity of 4.7 fb(-1) recorded by the CMS detector in pp collisions at √s=7 TeV from the LHC. Seventy-two events are observed with four-lepton invariant mass m(4ℓ)>100 GeV (with 13 below 160 GeV), while 67.1±6.0 (9.5±1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges of 134-158 GeV, 180-305 GeV, and 340-465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.

Search for signatures of extra dimensions in the diphoton mass spectrum at the large hadron collider

A search for signatures of extra spatial dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at √s=7 TeV corresponding to an integrated luminosity of 2.2 fb(-1). In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.