Why do subcutaneous ports get stuck? A case-control study.

PURPOSE: We sought to identify clinical features associated with difficult subcutaneous port removals in children. METHODS: Ports placed between April 2014 and September 2017 at our institution were prospectively tracked for difficult removals. A case-control analysis was performed. Patients with ports that were difficult to remove (stuck; cases) were compared to biological sex and age-matched controls in a ratio of 1:3. Logistic regression determined the association between case/control status and clinical features adjusting for biological sex and age as covariates. A multivariable analysis was performed to identify independent associations. RESULTS: 57 stuck ports (28 extreme [10 endovascular intervention] and 29 moderate) and 171 controls were analyzed. Stuck ports were associated with a diagnosis of acute lymphoblastic leukemia (86% cases versus 22.2% controls; p < 0.001) and a longer placement duration (median 2.6 years [interquartile range (IQR) 2.5-2.6] versus 0.8 years [IQR 0.5-1.4]; p < 0.001). On univariate analysis, procedural and device features associated with stuck ports included subclavian access (71.9% cases versus 48.5% controls; p = 0.0126), a polyurethane versus silicone catheter (96.5% cases versus 79.9% controls; p = 0.001), and a rough catheter appearance at removal (92.6% cases versus 9.4% controls; p < 0.0001). A diagnosis of ALL and duration of line placement were associated with having a stuck port on multivariate analysis. CONCLUSION: Polyurethane central venous catheters placed for the two-year treatment of acute lymphoblastic leukemia may become difficult to remove. This constellation of factors warrants more extensive preoperative discussion of risk, endovascular backup availability, and scheduling for longer operating room time.

Neutropenia at the time of subcutaneous port insertion may not be a risk factor for early infectious complications in pediatric oncology patients.

BACKGROUND: The risk of infection associated with subcutaneous port (SQP) placement in patients with neutropenia remains unclear. We reviewed the rate of early infectious complications (<30 days) following SQP placement in pediatric oncology patients with or without neutropenia [absolute neutrophil count (ANC) <500/mm3]. METHODS: Baseline characteristics and infectious complications were compared between groups using univariate and multivariate analyses. RESULTS: A total of 614 SQP were placed in 542 patients. Compared to nonneutropenic patients, those with neutropenia were more likely to have leukemia (n = 74, 94% vs n = 268, 50%), preoperative fever (n = 17, 22% vs n = 25, 5%), recent documented infection (n = 15, 19% vs n = 47, 9%), and were younger (81 vs 109 months) (p values <0.01). After adjusting for fever and underlying-disease, there was a nonsignificant association between neutropenia and early postoperative infection (OR 2.42, 95% CI 0.82-7.18, p = 0.11). Only preoperative fever was a predictor of infection (OR 6.09, 95% CI 2.08-17.81, p = 0.001). CONCLUSION: SQP placement appears safe in most neutropenic patients. TYPE OF STUDY: Retrospective comparative study. LEVEL OF EVIDENCE: Level III.

Impact of tumor histology and grade on treatment success of percutaneous renal cryoablation.

BACKGROUND: We analyzed oncological outcomes in patients who underwent percutaneous renal cryoablation (PRC) with documented renal cell carcinoma (RCC) by perioperative biopsy. METHODS: Multicenter retrospective analysis of 153 patients [median follow-up 48 months] who underwent PRC from 09/2005 to 08/2014 was performed. We divided the cohort into patients who developed recurrence versus no recurrence. Kaplan-Meier analyses examined recurrence-free survival (RFS) according to grade and histology. Multivariable analysis (MVA) was performed to identify factors associated with tumor recurrence. RESULTS: One hundred and fifty-three patients were analyzed [18 patients (11.8 %) with recurrence and 135 (88.2 %) patients without recurrence]. There were no differences between the groups with respect to demographics, RENAL score, and number of probes utilized. Recurrence group had larger tumor size (3.1 vs. 2.4 cm; p = 0.011), upper pole tumor location (p = 0.016), and greater proportions of high-grade tumor (33 vs. 0.7 %; p < 0.001) and clear cell histology (77.8 vs. 45.9 %; p = 0.011). Four-year RFS was 100 versus 80 % for grade 1 versus grade 2/3 tumors (p = 0.0002), and 97 versus 88 % for other RCC versus clear cell RCC (p = 0.07). MVA demonstrated tumor size >3 cm (OR 2.46; p = 0.019), clear cell histology (OR 2.12; p = 0.027), and high tumor grade (OR 2.33, p < 0.001) as independent risk factors associated with tumor recurrence. CONCLUSIONS: Association of higher grade and clear cell histology with recurrence and progression suggests need for increased emphasis on preoperative risk stratification by biopsy, with grade 1 and non-clear cell RCC being associated with improved treatment success than higher grade and clear cell RCC.

Initial diagnostic management of pediatric bone tumors.

BACKGROUND: Osteosarcoma (OS) and the Ewing sarcoma family of tumors (ESFT) are the most common primary pediatric bone malignancies. We sought to assess the diagnostic accuracy of initial tumor biopsies in patients with OS or ESFT at a pediatric cancer center. METHODS: All biopsies performed at initial presentation of patients with OS or ESFT at our institution from 2003 to 2012 were retrospectively reviewed. Diagnostic accuracy and incidence of complications were correlated with study variables using logistic regression analysis. RESULTS: One hundred forty-two biopsies were performed in 105 patients (median age 13.4years, range: 1.8-23.0), 104 (73.2%) OS and 38 (27.8%) ESFT. Thirty-one (21.8%) were performed on metastatic sites. Eighty-five (76.6%) of 111 primary site biopsies were open procedures, and 26 were percutaneous (23.4%). Primary site biopsies were successful in 94.1% of open and 73.1% of percutaneous procedures. Odds of obtaining a successful diagnostic specimen were 7.8 times higher with open approach (CI: 1.6-36.8). Metastatic site biopsies were successful in 66.7% of percutaneous and 100% of open and thoracoscopic procedures. CONCLUSION: Biopsy of metastatic sites was equal to primary site in obtaining diagnostic material with the added benefit of accurate staging, with few adverse events and high diagnostic yield.

Distinguishing Osteomyelitis From Ewing Sarcoma on Radiography and MRI.

OBJECTIVE: The purpose of this study was to determine whether clinical and imaging features can distinguish osteomyelitis from Ewing sarcoma (EWS) and to assess the accuracy of percutaneous biopsy versus open biopsy in the diagnosis of these diseases. MATERIALS AND METHODS: Three radiologists reviewed the radiographs and MRI examinations of 32 subjects with osteomyelitis and 31 subjects with EWS to determine the presence of 36 imaging parameters. Information on demographic characteristics, history, physical examination findings, laboratory findings, biopsy type, and biopsy results were recorded. Individual imaging and clinical parameters and combinations of these parameters were tested for correlation with findings from histologic analysis. The diagnostic accuracy of biopsy was also determined. RESULTS: On radiography, the presence of joint or metaphyseal involvement, a wide transition zone, a Codman triangle, a periosteal reaction, or a soft-tissue mass, when tested individually, was more likely to be noted in subjects with EWS (p ≤ 0.05) than in subjects with osteomyelitis. On MRI, permeative cortical involvement and soft-tissue mass were more likely in subjects with EWS (p ≤ 0.02), whereas a serpiginous tract was more likely to be seen in subjects with osteomyelitis (p = 0.04). African Americans were more likely to have osteomyelitis than EWS (p = 0). According to the results of multiple regression analysis, only ethnicity and soft-tissue mass remained statistically significant (p ≤ 0.01). The findings from 100% of open biopsies (18/18) and 58% of percutaneous biopsies (7/12) resulted in the diagnosis of osteomyelitis, whereas the findings from 88% of open biopsies (22/25) and 50% of percutaneous biopsies (3/6) resulted in a diagnosis of EWS. CONCLUSION: Several imaging features are significantly associated with either EWS or osteomyelitis, but many features are associated with both diseases. Other than ethnicity, no clinical feature improved diagnostic accuracy. Compared with percutaneous biopsy, open biopsy provides a higher diagnostic yield but may be inconclusive, especially for cases of EWS. Our findings underscore the need for better methods of diagnosing these disease processes.

Safety and diagnostic accuracy of tumor biopsies in children with cancer.

BACKGROUND: Tumor biopsies are central to the diagnosis and management of cancer and are critical to efforts in personalized medicine and targeted therapeutics. In the current study, the authors sought to evaluate the safety and accuracy of biopsies in children with cancer. METHODS: All biopsies performed in children at the study institution with a suspected or established diagnosis of cancer from 2003 through 2012 were reviewed retrospectively. Patient characteristics and disease-related and procedure-related factors were correlated with procedure-related complications and diagnostic accuracy using logistic regression analysis. RESULTS: A total of 1073 biopsies were performed in 808 patients. Of 1025 biopsies with adequate follow-up, 79 (7.7%) were associated with an adverse event, 35 (3.4%) of which were minor (grade 1-2) and 32 (3.1%) of which were major (grade 3-4) (grading was performed according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). The most common major adverse events were blood transfusion (>10 mL/kg; 24 cases) and infection requiring intravenous antibiotics (6 cases). Eleven deaths (1.4%) occurred within 30 days after the procedure, but the procedure may have contributed to the outcome in only 2 cases. A total of 926 biopsies (90.3%) provided definitive histologic diagnoses. Using multivariable analysis, biopsy site, preprocedure hematocrit level, and body mass index were found to be associated with the risk of postprocedural complications (P<.0001, P<.0001, and P =.0029, respectively). Excisional biopsy and biopsy site were found to be independently associated with obtaining a diagnostic result (P =.0002 and P =.0008, respectively). CONCLUSIONS: Tumor biopsies in children with cancer are associated with a low incidence of complications and a high rate of diagnostic accuracy. The predictive factors identified for adverse outcomes may aid in risk assessment and preprocedural counseling.

RENAL nephrometry score is associated with complications after renal cryoablation: a multicenter analysis.

OBJECTIVE: To analyze outcomes and complications of percutaneous (PRC) and laparoscopic renal cryoablation (LRC) using the radius, endophytic, nearness to collecting system, anterior/posterior, and location (RENAL) nephrometry system. METHODS: Retrospective multicenter analysis of 154 consecutive patients who underwent either ultrasound-guided LRC (n = 88) or computed tomography (CT)-guided PRC (n = 66) from March 2003 to December 2011. RENAL score and demographics were compared to postoperative complications (Clavien). Multivariable analysis was carried out for factors associated with development of postprocedure complications. RESULTS: Mean age was 68 years (94 men/60 women). Median follow-up was 34 months (range 23.6-45.6 months). Mean tumor size was 2.6 ± 1 cm. Mean RENAL score was 5.2 ± 1.4. Differences in (A)nterior/posterior component and (H)ilar domain of the RENAL scores were noted, with PRC favoring posterior tumors and hilar lesions compared to LRC (P < .001 and P = .044, respectively). There were 14.9% complications, all of which were low-grade (Clavien 1,2). There were no differences in complications between LRC and PRC (15.9% vs 13.6%, P = .82). Most common complication type was hemorrhagic in 9 of 154 patients (5.8%); significant increase in the hemorrhagic complication rate was noted for patients with "N" ("nearness") component score of 2 or 3 (5/36, or 13.9%), compared to patients with "N" score of 1 (4/115 or 3.5%, P = .033). multivariable analysis demonstrated that increasing RENAL score was associated with postprocedure complications (odds ratio [OR] = 1.37, P = .025). When separated into individual domains, multivariable analysis revealed that "N" score 3 was significantly associated with postoperative complications (OR 16.15, P = .027). CONCLUSION: Increasing RENAL score was associated development of postprocedure complications after renal cryotherapy. Further investigation is requisite to elucidate the role of RENAL nephrometry score in risk stratification prior to renal cryotherapy.

MESSENGER observations of transient bursts of energetic electrons in Mercury's magnetosphere.

The MESSENGER spacecraft began detecting energetic electrons with energies greater than 30 kilo-electron volts (keV) shortly after its insertion into orbit about Mercury. In contrast, no energetic protons were observed. The energetic electrons arrive as bursts lasting from seconds to hours and are most intense close to the planet, distributed in latitude from the equator to the north pole, and present at most local times. Energies can exceed 200 keV but often exhibit cutoffs near 100 keV. Angular distributions of the electrons about the magnetic field suggest that they do not execute complete drift paths around the planet. This set of characteristics demonstrates that Mercury's weak magnetic field does not support Van Allen-type radiation belts, unlike all other planets in the solar system with internal magnetic fields.

MESSENGER observations of extreme loading and unloading of Mercury's magnetic tail.

During MESSENGER's third flyby of Mercury, the magnetic field in the planet's magnetic tail increased by factors of 2 to 3.5 over intervals of 2 to 3 minutes. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is lower by a factor of approximately 10 and typical durations are approximately 1 hour. The extreme tail loading observed at Mercury implies that the relative intensity of substorms must be much larger than at Earth. The correspondence between the duration of tail field enhancements and the characteristic time for the Dungey cycle, which describes plasma circulation through Mercury's magnetosphere, suggests that such circulation determines the substorm time scale. A key aspect of tail unloading during terrestrial substorms is the acceleration of energetic charged particles, but no acceleration signatures were seen during the MESSENGER flyby.

MESSENGER observations of magnetic reconnection in Mercury's magnetosphere.

Solar wind energy transfer to planetary magnetospheres and ionospheres is controlled by magnetic reconnection, a process that determines the degree of connectivity between the interplanetary magnetic field (IMF) and a planet's magnetic field. During MESSENGER's second flyby of Mercury, a steady southward IMF was observed and the magnetopause was threaded by a strong magnetic field, indicating a reconnection rate ~10 times that typical at Earth. Moreover, a large flux transfer event was observed in the magnetosheath, and a plasmoid and multiple traveling compression regions were observed in Mercury's magnetotail, all products of reconnection. These observations indicate that Mercury's magnetosphere is much more responsive to IMF direction and dominated by the effects of reconnection than that of Earth or the other magnetized planets.

Mercury's magnetosphere after MESSENGER's first flyby.

Observations by MESSENGER show that Mercury's magnetosphere is immersed in a comet-like cloud of planetary ions. The most abundant, Na+, is broadly distributed but exhibits flux maxima in the magnetosheath, where the local plasma flow speed is high, and near the spacecraft's closest approach, where atmospheric density should peak. The magnetic field showed reconnection signatures in the form of flux transfer events, azimuthal rotations consistent with Kelvin-Helmholtz waves along the magnetopause, and extensive ultralow-frequency wave activity. Two outbound current sheet boundaries were observed, across which the magnetic field decreased in a manner suggestive of a double magnetopause. The separation of these current layers, comparable to the gyro-radius of a Na+ pickup ion entering the magnetosphere after being accelerated in the magnetosheath, may indicate a planetary ion boundary layer.

MArs Neutron Energy Spectrometer (MANES): an instrument for the Mars 2003 Lander.

We describe the instrument design and detector development for MANES which has been selected to fly on the Mars 2003 Lander. Section 1 explains the need for the spectrometer in determining the increased risk of carcinogenesis for astronauts. Section 2 presents the instrument design including an outline drawing, a cross-sectional view and a detailed block diagram. Sections 3 and 4 describe the low and high energy detector components of the spectrometer and present responses to monoenergetic neutron beams. Sections 5 and 6 explain the design approaches to charged particle discrimination and instrument transfer function modeling.