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Dive into the research topics where Tamara D. Simon is active.

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Featured researches published by Tamara D. Simon.


Pediatrics | 2010

Children With Complex Chronic Conditions in Inpatient Hospital Settings in the United States

Tamara D. Simon; Jay G. Berry; Chris Feudtner; Bryan L. Stone; Xiaoming Sheng; Susan L. Bratton; J. Michael Dean; Rajendu Srivastava

OBJECTIVES: Hospitalized children are perceived to be increasingly medically complex, but no such trend has been documented. The objective of this study was to determine whether the proportion of pediatric inpatient use that is attributable to patients with a diagnosis of one or more complex chronic condition (CCC) has increased over time and to assess the degree to which CCC hospitalizations are associated with attributes that are consistent with heightened medical complexity. METHODS: A retrospective observational study that used the 1997, 2000, 2003, and 2006 Kids Inpatient Databases examined US hospitalizations for children. Attributes of medical complexity included hospital admissions, length of stay, total charges, technology-assistance procedures, and mortality risk. RESULTS: The proportion of inpatient pediatric admissions, days, and charges increased from 1997 to 2006 for any CCC and for every CCC group except hematology. CCCs accounted for 8.9% of US pediatric admissions in 1997 and 10.1% of admissions in 2006. These admissions used 22.7% to 26.1% of pediatric hospital days, used 37.1% to 40.6% of pediatric hospital charges, accounted for 41.9% to 43.2% of deaths, and (for 2006) used 73% to 92% of different forms of technology-assistance procedures. As the number of CCCs for a given admission increased, all markers of use increased. CONCLUSIONS: CCC-associated hospitalizations compose an increasing proportion of inpatient care and resource use. Future research should seek to improve methods to identify the population of medically complex children, monitor their increasing inpatient use, and assess whether current systems of care are meeting their needs.


Pediatrics | 2011

Children With Medical Complexity: An Emerging Population for Clinical and Research Initiatives

Eyal Cohen; Dennis Z. Kuo; Rishi Agrawal; Jay G. Berry; Santi K. M. Bhagat; Tamara D. Simon; Rajendu Srivastava

Children with medical complexity (CMC) have medical fragility and intensive care needs that are not easily met by existing health care models. CMC may have a congenital or acquired multisystem disease, a severe neurologic condition with marked functional impairment, and/or technology dependence for activities of daily living. Although these children are at risk of poor health and family outcomes, there are few well-characterized clinical initiatives and research efforts devoted to improving their care. In this article, we present a definitional framework of CMC that consists of substantial family-identified service needs, characteristic chronic and severe conditions, functional limitations, and high health care use. We explore the diversity of existing care models and apply the principles of the chronic care model to address the clinical needs of CMC. Finally, we suggest a research agenda that uses a uniform definition to accurately describe the population and to evaluate outcomes from the perspectives of the child, the family, and the broader health care system.


Journal of Neurosurgery | 2009

Infection rates following initial cerebrospinal fluid shunt placement across pediatric hospitals in the United States: Clinical article

Tamara D. Simon; Matthew Hall; Jay Riva-Cambrin; J. Elaine Albert; Howard E. Jeffries; Bonnie LaFleur; J. Michael Dean; John R. W. Kestle

OBJECT Reported rates of CSF shunt infection vary widely across studies. The study objective was to determine the CSF shunt infection rates after initial shunt placement at multiple US pediatric hospitals. The authors hypothesized that infection rates between hospitals would vary widely even after adjustment for patient, hospital, and surgeon factors. METHODS This retrospective cohort study included children 0-18 years of age with uncomplicated initial CSF shunt placement performed between January 1, 2001, and December 31, 2005, and recorded in the Pediatric Health Information System (PHIS) longitudinal administrative database from 41 childrens hospitals. For each child with 24 months of follow-up, subsequent CSF shunt infections and procedures were determined. RESULTS The PHIS database included 7071 children with uncomplicated initial CSF shunt placement during this time period. During the 24 months of follow-up, these patients had a total of 825 shunt infections and 4434 subsequent shunt procedures. Overall unadjusted 24-month CSF shunt infection rates were 11.7% per patient and 7.2% per procedure. Unadjusted 24-month cumulative incidence rates for each hospital ranged from 4.1 to 20.5% per patient and 2.5-12.3% per procedure. Factors significantly associated with infection (p < 0.05) included young age, female sex, African-American race, public insurance, etiology of intraventricular hemorrhage, respiratory complex chronic condition, subsequent revision procedures, hospital volume, and surgeon case volume. Malignant lesions and trauma as etiologies were protective. Infection rates for each hospital adjusted for these factors decreased to 8.8-12.8% per patient and 1.4-5.3% per procedure. CONCLUSIONS Infections developed in > 11% of children who underwent uncomplicated initial CSF shunt placements within 24 months. Patient, hospital, and surgeon factors contributed somewhat to the wide variation in CSF shunt infection rates across hospitals. Additional factors may contribute to variation in CSF shunt infection rates between centers, but further study is needed. Benchmarking and future prospective multicenter studies of CSF shunt infection will need to incorporate these and other patient, hospital, and surgeon factors.


Pediatrics | 2014

Pediatric Medical Complexity Algorithm: A New Method to Stratify Children by Medical Complexity

Tamara D. Simon; Mary Lawrence Cawthon; Susan Stanford; Jean Popalisky; Dorothy Lyons; Peter Woodcox; Margaret Hood; Alex Y. Chen; Rita Mangione-Smith

OBJECTIVES: The goal of this study was to develop an algorithm based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), codes for classifying children with chronic disease (CD) according to level of medical complexity and to assess the algorithm’s sensitivity and specificity. METHODS: A retrospective observational study was conducted among 700 children insured by Washington State Medicaid with ≥1 Seattle Children’s Hospital emergency department and/or inpatient encounter in 2010. The gold standard population included 350 children with complex chronic disease (C-CD), 100 with noncomplex chronic disease (NC-CD), and 250 without CD. An existing ICD-9-CM–based algorithm called the Chronic Disability Payment System was modified to develop a new algorithm called the Pediatric Medical Complexity Algorithm (PMCA). The sensitivity and specificity of PMCA were assessed. RESULTS: Using hospital discharge data, PMCA’s sensitivity for correctly classifying children was 84% for C-CD, 41% for NC-CD, and 96% for those without CD. Using Medicaid claims data, PMCA’s sensitivity was 89% for C-CD, 45% for NC-CD, and 80% for those without CD. Specificity was 90% to 92% in hospital discharge data and 85% to 91% in Medicaid claims data for all 3 groups. CONCLUSIONS: PMCA identified children with C-CD (who have accessed tertiary hospital care) with good sensitivity and good to excellent specificity when applied to hospital discharge or Medicaid claims data. PMCA may be useful for targeting resources such as care coordination to children with C-CD.


Journal of Neurosurgery | 2011

A standardized protocol to reduce cerebrospinal fluid shunt infection: The Hydrocephalus Clinical Research Network Quality Improvement Initiative

John R. W. Kestle; Jay Riva-Cambrin; John C. Wellons; Abhaya V. Kulkarni; William E. Whitehead; Marion L. Walker; W. Jerry Oakes; James M. Drake; Thomas G. Luerssen; Tamara D. Simon; Richard Holubkov

OBJECT Quality improvement techniques are being implemented in many areas of medicine. In an effort to reduce the ventriculoperitoneal shunt infection rate, a standardized protocol was developed and implemented at 4 centers of the Hydrocephalus Clinical Research Network (HCRN). METHODS The protocol was developed sequentially by HCRN members using the current literature and prior institutional experience until consensus was obtained. The protocol was prospectively applied at each HCRN center to all children undergoing a shunt insertion or revision procedure. Infections were defined on the basis of CSF, wound, or pseudocyst cultures; wound breakdown; abdominal pseudocyst; or positive blood cultures in the presence of a ventriculoatrial shunt. Procedures and infections were measured before and after protocol implementation. RESULTS Twenty-one surgeons at 4 centers performed 1571 procedures between June 1, 2007, and February 28, 2009. The minimum follow-up was 6 months. The Network infection rate decreased from 8.8% prior to the protocol to 5.7% while using the protocol (p = 0.0028, absolute risk reduction 3.15%, relative risk reduction 36%). Three of 4 centers lowered their infection rate. Shunt surgery after external ventricular drainage (with or without prior infection) had the highest infection rate. Overall protocol compliance was 74.5% and improved over the course of the observation period. Based on logistic regression analysis, the use of BioGlide catheters (odds ratio [OR] 1.91, 95% CI 1.19-3.05; p = 0.007) and the use of antiseptic cream by any members of the surgical team (instead of a formal surgical scrub by all members of the surgical team; OR 4.53, 95% CI 1.43-14.41; p = 0.01) were associated with an increased risk of infection. CONCLUSIONS The standardized protocol for shunt surgery significantly reduced shunt infection across the HCRN. Overall protocol compliance was good. The protocol has established a common baseline within the Network, which will facilitate assessment of new treatments. Identification of factors associated with infection will allow further protocol refinement in the future.


Journal of Neurosurgery | 2014

Endoscopic third ventriculostomy and choroid plexus cauterization in infants with hydrocephalus: a retrospective Hydrocephalus Clinical Research Network study

Abhaya V. Kulkarni; Jay Riva-Cambrin; Samuel R. Browd; James M. Drake; Richard Holubkov; John R. W. Kestle; David D. Limbrick; Curtis J. Rozzelle; Tamara D. Simon; Mandeep S. Tamber; John C. Wellons; William E. Whitehead

OBJECT The use of endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) has been advocated as an alternative to CSF shunting in infants with hydrocephalus. There are limited reports of this procedure in the North American population, however. The authors provide a retrospective review of the experience with combined ETV + CPC within the North American Hydrocephalus Clinical Research Network (HCRN). METHODS All children (< 2 years old) who underwent an ETV + CPC at one of 7 HCRN centers before November 2012 were included. Data were collected retrospectively through review of hospital records and the HCRN registry. Comparisons were made to a contemporaneous cohort of 758 children who received their first shunt at < 2 years of age within the HCRN. RESULTS Thirty-six patients with ETV + CPC were included (13 with previous shunt). The etiologies of hydrocephalus were as follows: intraventricular hemorrhage of prematurity (9 patients), aqueductal stenosis (8), myelomeningocele (4), and other (15). There were no major intraoperative or early postoperative complications. There were 2 postoperative CSF infections. There were 2 deaths unrelated to hydrocephalus and 1 death from seizure. In 18 patients ETV + CPC failed at a median time of 30 days after surgery (range 4-484 days). The actuarial 3-, 6-, and 12-month success for ETV + CPC was 58%, 52%, and 52%. Time to treatment failure was slightly worse for the 36 patients with ETV + CPC compared with the 758 infants treated with shunts (p = 0.012). Near-complete CPC (≥ 90%) was achieved in 11 cases (31%) overall, but in 50% (10 of 20 cases) in 2012 versus 6% (1 of 16 cases) before 2012 (p = 0.009). Failure was higher in children with < 90% CPC (HR 4.39, 95% CI 0.999-19.2, p = 0.0501). CONCLUSIONS The early North American multicenter experience with ETV + CPC in infants demonstrates that the procedure has reasonable safety in selected cases. The degree of CPC achieved might be associated with a surgeons learning curve and appears to affect success, suggesting that surgeon training might improve results.


Journal of Neurosurgery | 2009

A multicenter retrospective comparison of conversion from temporary to permanent cerebrospinal fluid diversion in very low birth weight infants with posthemorrhagic hydrocephalus.

John C. Wellons; Chevis N. Shannon; Abhaya V. Kulkarni; Tamara D. Simon; Jay Riva-Cambrin; William E. Whitehead; W. Jerry Oakes; James M. Drake; Thomas G. Luerssen; Marion L. Walker; John R. W. Kestle

OBJECT The purpose of this study was to define the incidence of permanent shunt placement and infection in patients who have undergone the 2 most commonly performed temporizing procedures for posthemorrhagic hydrocephalus (PHH) of prematurity: ventriculosubgaleal (VSG) shunt placement and ventricular reservoir placement for intermittent tapping. METHODS The 4 centers of the Hydrocephalus Clinical Research Network participated in a retrospective chart review of infants with PHH who underwent treatment at each institution between 2001 and 2006. Patients were included if they had received a diagnosis of Grade 3 or 4 intraventricular hemorrhage, weighed < 1500 g at birth, and had received surgical intervention. The authors determined the incidence of conversion from a temporizing device to a permanent shunt, the incidence of CSF infection during temporization, and the 6-month CSF infection rate after permanent shunt placement. RESULTS Thirty-one (86%) of 36 patients who received VSG shunts and 61 (69%) of 88 patients who received ventricular reservoirs received permanent CSF diversion with a shunt (p = 0.05). Five patients (14%) in the VSG shunt group had CSF infections during temporization, compared with 11 patients (13%) in the ventricular reservoir group (p = 0.83). The 6-month incidence of permanent shunt infection in the VSG shunt group was 16% (5 of 31), compared with 12% (7 of 61) in the reservoir placement group (p = 0.65). For the first 6 months after permanent shunt placement, infants with no preceding temporizing procedure had an infection rate of 5% (1 of 20 infants) and those who had undergone a temporizing procedure had an infection rate of 13% (12 of 92; p = 0.45). CONCLUSIONS The use of intermittent tapping of ventricular reservoirs in this population appears to lead to a lower incidence of permanent shunt placement than the use of VSG shunts. The incidence of infection during temporization and for the initial 6 months after conversion appears comparable for both groups. The apparent difference identified in this pilot study requires confirmation in a more rigorous study.


The Journal of Pediatrics | 2014

Risk Factors for First Cerebrospinal Fluid Shunt Infection: Findings from a Multi-Center Prospective Cohort Study

Tamara D. Simon; Jeremiah Butler; Kathryn B. Whitlock; Samuel R. Browd; Richard Holubkov; John R. W. Kestle; Abhaya V. Kulkarni; Marcie Langley; David D. Limbrick; Nicole Mayer-Hamblett; Mandeep S. Tamber; John C. Wellons; William E. Whitehead; Jay Riva-Cambrin

OBJECTIVE To quantify the extent to which cerebrospinal fluid (CSF) shunt revisions are associated with increased risk of CSF shunt infection, after adjusting for patient factors that may contribute to infection risk. STUDY DESIGN We used the Hydrocephalus Clinical Research Network registry to assemble a large prospective 6-center cohort of 1036 children undergoing initial CSF shunt placement between April 2008 and January 2012. The primary outcome of interest was first CSF shunt infection. Data for initial CSF shunt placement and all subsequent CSF shunt revisions prior to first CSF shunt infection, where applicable, were obtained. The risk of first infection was estimated using a multivariable Cox proportional hazard model accounting for patient characteristics and CSF shunt revisions, and is reported using hazard ratios (HRs) with 95% CI. RESULTS Of the 102 children who developed first infection within 12 months of placement, 33 (32%) followed one or more CSF shunt revisions. Baseline factors independently associated with risk of first infection included: gastrostomy tube (HR 2.0, 95% CI, 1.1, 3.3), age 6-12 months (HR 0.3, 95% CI, 0.1, 0.8), and prior neurosurgery (HR 0.4, 95% CI, 0.2, 0.9). After controlling for baseline factors, infection risk was most significantly associated with the need for revision (1 revision vs none, HR 3.9, 95% CI, 2.2, 6.5; ≥2 revisions, HR 13.0, 95% CI, 6.5, 24.9). CONCLUSIONS This study quantifies the elevated risk of infection associated with shunt revisions observed in clinical practice. To reduce risk of infection risk, further work should optimize revision procedures.


Journal of Neurosurgery | 2013

Outcomes of CSF shunting in children: comparison of Hydrocephalus Clinical Research Network cohort with historical controls

Abhaya V. Kulkarni; Jay Riva-Cambrin; Jerry Butler; Samuel R. Browd; James M. Drake; Richard Holubkov; John R. W. Kestle; David D. Limbrick; Tamara D. Simon; Mandeep S. Tamber; John C. Wellons; William E. Whitehead

OBJECT The Hydrocephalus Clinical Research Network (HCRN), which comprises 7 pediatric neurosurgical centers in North America, provides a unique multicenter assessment of the current outcomes of CSF shunting in nonselected patients. The authors present the initial results for this cohort and compare them with results from prospective multicenter trials performed in the 1990s. METHODS Analysis was restricted to patients with newly diagnosed hydrocephalus undergoing shunting for the first time. Detailed perioperative data from 2008 through 2012 for all HCRN centers were prospectively collected and centrally stored by trained research coordinators. Historical control data were obtained from the Shunt Design Trial (1993-1995) and the Endoscopic Shunt Insertion Trial (1996-1999). The primary outcome was time to first shunt failure, which was determined by using Cox regression survival analysis. RESULTS Mean age of the 1184 patients in the HCRN cohort was older than mean age of the 720 patients in the historical cohort (2.51 years vs 1.60 years, p < 0.0001). The distribution of etiologies differed (p < 0.0001, chi-square test); more tumors and fewer myelomeningoceles caused the hydrocephalus in the HCRN cohort patients. The hazard ratio for first shunt failure significantly favored the HCRN cohort, even after the model was adjusted for the prognostic effects of age and etiology (adjusted HR 0.82, 95% CI 0.69-0.96). CONCLUSIONS Current outcomes of shunting in general pediatric neurosurgery practice have improved over those from the 1990s, although the reasons remain unclear.


Journal of Neurosurgery | 2016

Risk factors for shunt malfunction in pediatric hydrocephalus: a multicenter prospective cohort study

Jay Riva-Cambrin; John R. W. Kestle; Richard Holubkov; Jerry Butler; Abhaya V. Kulkarni; James Drake MBBCh; William E. Whitehead; John C. Wellons; Chevis N. Shannon; Mandeep S. Tamber; David D. Limbrick; Curtis J. Rozzelle; Samuel R. Browd; Tamara D. Simon

OBJECT The rate of CSF shunt failure remains unacceptably high. The Hydrocephalus Clinical Research Network (HCRN) conducted a comprehensive prospective observational study of hydrocephalus management, the aim of which was to isolate specific risk factors for shunt failure. METHODS The study followed all first-time shunt insertions in children younger than 19 years at 6 HCRN centers. The HCRN Investigator Committee selected, a priori, 21 variables to be examined, including clinical, radiographic, and shunt design variables. Shunt failure was defined as shunt revision, subsequent endoscopic third ventriculostomy, or shunt infection. Important a priori-defined risk factors as well as those significant in univariate analyses were then tested for independence using multivariate Cox proportional hazard modeling. RESULTS A total of 1036 children underwent initial CSF shunt placement between April 2008 and December 2011. Of these, 344 patients experienced shunt failure, including 265 malfunctions and 79 infections. The mean and median length of follow-up for the entire cohort was 400 days and 264 days, respectively. The Cox model found that age younger than 6 months at first shunt placement (HR 1.6 [95% CI 1.1-2.1]), a cardiac comorbidity (HR 1.4 [95% CI 1.0-2.1]), and endoscopic placement (HR 1.9 [95% CI 1.2-2.9]) were independently associated with reduced shunt survival. The following had no independent associations with shunt survival: etiology, payer, center, valve design, valve programmability, the use of ultrasound or stereotactic guidance, and surgeon experience and volume. CONCLUSIONS This is the largest prospective study reported on children with CSF shunts for hydrocephalus. It confirms that a young age and the use of the endoscope are risk factors for first shunt failure and that valve type has no impact. A new risk factor-an existing cardiac comorbidity-was also associated with shunt failure.

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David D. Limbrick

Washington University in St. Louis

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