Risk Factors for Rescue Opioid Prescription After Cubital Tunnel Surgery.

BACKGROUND: Concerns regarding the ongoing opioid epidemic have led to heightened scrutiny of postoperative opioid prescribing patterns for common orthopedic surgical procedures. This study investigated patient- and procedure-specific risk factors for additional postoperative opioid rescue prescriptions following ambulatory cubital tunnel surgery. METHODS: A retrospective review was performed of patients who underwent cubital tunnel surgery at 2 academic medical centers between June 1, 2015 and March 1, 2020. Patient demographics, comorbidities, prior opioid history, and surgical variables were recorded. The primary outcome was postoperative rescue opioid prescription. Univariate and bivariate statistical analyses were performed. RESULTS: Two hundred seventy-four patients were included, of whom 171 (62%) underwent in situ ulnar nerve decompression and 103 (38%) underwent ulnar nerve decompression with anterior transposition. The median postoperative opioid prescription amount was 90 morphine equivalent units (MEU) for the total cohort, 77.5 MEU for in situ ulnar nerve decompression, and 112.5 MEU for ulnar nerve decompression with transposition. Twenty-two patients (8%) required additional rescue opioid prescriptions postoperatively. Female sex, fibromyalgia, chronic opioid use, chronic pain diagnosis, and recent opioid were associated with the need for additional postoperative rescue opioid prescriptions. CONCLUSIONS: While most patients do not require additional rescue opioid prescriptions after cubital tunnel surgery, chronic pain patients and patients with pain sensitivity syndromes are at risk for requiring additional rescue opioid prescriptions. For these high-risk patients, preoperative collaboration of a multidisciplinary team may be beneficial for developing a perioperative pain management plan that is both safe and effective.

Do Socioeconomic Factors Affect Symptom Duration and Disease Severity at Presentation for Cubital Tunnel Syndrome?

BACKGROUND: Socioeconomic factors have been implicated in delayed presentation for compressive neuropathies of the upper extremity. Our article seeks to elucidate the effect of socioeconomic factors on self-reported symptom duration and objective disease severity at presentation for cubital tunnel syndrome. METHODS: This retrospective cohort study included 207 patients with surgical management of cubital tunnel syndrome at 2 institutions between June 1, 2015, and March 1, 2020. Exclusion criteria included age under 18 years, revision surgery, lack of preoperative electrodiagnostic studies, and concurrent additional surgeries. Response variables were self-reported symptom duration, time from presentation to surgery, McGowan grade, and electrodiagnostic measures. Explanatory variables included age, sex, white race, diabetes mellitus, depression, anxiety, and the Distressed Communities Index. RESULTS: Symptom duration was associated with nonwhite race, and time from presentation to surgery was associated with insurance provider. More clinically severe disease was associated with older age, male sex, and not having carpal tunnel syndrome. Nonrecordable sensory nerve action potential latency was associated with older age, higher body mass index, male sex, diabetes mellitus, and unemployment. Nonrecordable conduction velocities were associated with older age, and having fibrillations at presentation was associated with older age, male sex, and unemployment. CONCLUSIONS: Economic distress is not associated with self-reported symptom duration, time from presentation to surgery, or presenting severity of cubital tunnel syndrome. White patients presented with shorter self-reported symptom duration. Insurance type was associated with delay from presentation to surgery. Older age and male sex were risk factors for more clinically severe disease at presentation.

Does the Surgical Assistant Influence Perioperative Outcomes Surrounding Cubital Tunnel Surgery?

Background: Ulnar neuropathy at the elbow is the second most common upper extremity compressive neuropathy and surgical treatment often involves surgical trainee involvement. The primary aim of this study is to determine the effect of trainees and surgical assistants on outcomes surrounding cubital tunnel surgery. Methods: This retrospective study included 274 patients with cubital tunnel syndrome who underwent primary cubital tunnel surgery at two academic medical centres between 1 June 2015 and 1 March 2020. The patients were divided into four main cohorts based on primary surgical assistant: physician associates (PA, n = 38), orthopaedic or plastic surgery residents (n = 91), hand surgery fellows (n = 132), or both residents and fellows (n = 13). Exclusion criteria included patient age <18 years, revision surgery as the index procedure, prior traumatic ulnar nerve injury and concurrent procedures not related to cubital tunnel surgery. Demographics, clinical variables and perioperative findings were collected through chart reviews. Univariate and bivariate analyses were performed, and p < 0.05 was considered significant. Results: Patients in all cohorts had similar demographic and clinical characteristics. There was a significantly higher rate of subcutaneous transposition in the PA cohort (39.5% PA vs. 13.2% Resident vs. 19.7% Fellow vs. 15.4% Resident + Fellow). Presence of surgical assistants and trainees had no association with length of surgery, complications and reoperation rates. Although male sex and ulnar nerve transposition were associated with longer operative times, no explanatory variables were associated with complications or reoperation rates. Conclusions: Surgical trainee involvement in cubital tunnel surgery is safe and has no effect on operative time, complications or reoperation rates. Understanding the role of trainees and measuring the effect of graduated responsibility in surgery is important for medical training and safe patient care. Level of Evidence: Level III (Therapeutic).

Meningioma systematic reviews and meta-analyses: an assessment of reporting and methodological quality.

INTRODUCTION: Systematic reviews (SR) and systematic reviews with meta-analysis (SRMA) can constitute the highest level of research evidence. Such evidence syntheses are relied upon heavily to inform the clinical knowledge base and to guide clinical practice for meningioma. This review evaluates the reporting and methodological quality of published meningioma evidence syntheses to date. METHODS: Eight electronic databases/registries were searched to identify eligible meningioma SRs with and without meta-analysis published between January 1990 and December 2020. Articles concerning spinal meningioma were excluded. Reporting and methodological quality were assessed against the following tools: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), A MeaSurement Tool to Assess systematic Reviews (AMSTAR 2), and Risk Of Bias in Systematic reviews (ROBIS). RESULTS: 116 SRs were identified, of which 57 were SRMAs (49.1%). The mean PRISMA score for SRMA was 20.9 out of 27 (SD 3.9, 77.0% PRISMA adherence) and for SR without meta-analysis was 13.8 out of 22 (SD 3.4, 63% PRISMA adherence). Thirty-eight studies (32.8%) achieved greater than 80% adherence to PRISMA. Methodological quality assessment against AMSTAR 2 revealed that 110 (94.8%) studies were of critically low quality. Only 21 studies (18.1%) were judged to have a low risk of bias against ROBIS. CONCLUSION: The reporting and methodological quality of meningioma evidence syntheses was poor. Established guidelines and critical appraisal tools may be used as an adjunct to aid methodological conduct and reporting of such reviews, in order to improve the validity and transparency of research which may influence clinical practice.

How Sublimation Delays the Onset of Dusty Debris Disk Formation Around White Dwarf Stars.

Although numerous white dwarf stars host dusty debris disks, the temperature distribution of these stars differs significantly from the white dwarf population as a whole. Dusty debris disks exist exclusively around white dwarfs cooler than 27,000 K. This is all the more enigmatic given that the formation processes of dusty debris disks should favor younger, hotter white dwarfs, which likely host more dynamically unstable planetary systems. Here we apply a sophisticated material sublimation model to white dwarf systems to show that these statistics are actually a natural result of the interplay of thermal and tidal forces, and show how they define the circumstellar regions where dusty debris disks can form. We demonstrate that these processes tend to prevent stability against both sublimative destruction and reaccretion into planetesimals for rocky materials until white dwarfs cool to below ~25,000-32,000 K, in agreement with the observed limit of ~27,000 K. For pure water ice, this critical temperature is less than 2,700 K (requiring a cooling age older the universe); this precludes pure water ice-rich debris disks forming through the accepted two-step mechanism. The critical temperature is size-dependent; more massive white dwarfs could potentially host dusty debris disks at warmer temperatures.. Our model suggests that the location of the disks within the PG 0010+280, GD 56, GD 362, and PG 1541+651 systems are consistent with a forsterite-dominated olivine composition. We also find that very cool white dwarfs may simultaneously host multiple, independently formed dusty debris disks, consistent with observations of the LSPM J0207+3331 system.

Classic Hodgkin Lymphoma: A Nonclassic Presentation.

Hodgkin lymphoma classically presents as lymphadenopathy with contiguous spread with or without associated B symptoms including night sweats, weight loss, and fever. With timely diagnosis and treatment, this is a potentially curable disease. This report describes a unique case of Hodgkin lymphoma that presented with localized back pain without overt evidence of lymph node involvement. This nonclassic presentation offers a diagnostic challenge that emphasizes the importance of keeping a broad differential in an adolescent or young adult patient with lytic bone lesions.

Osteoarthritis, Osteophytes, and Enthesophytes Affect Biomechanical Function in Adults With X-linked Hypophosphatemia.

CONTEXT: X-Linked hypophosphatemia (XLH) is a lifelong metabolic disease with musculoskeletal comorbidities that dominate the adult clinical presentation. OBJECTIVE: The adult XLH disorder has yet to be quantified on the basis of the physical and functional limitations that can affect activities of daily living. Our goal was to report the impact of the musculoskeletal manifestations on physical function. DESIGN AND SETTING: Musculoskeletal function was evaluated by validated questionnaires and in an interdisciplinary clinical space where participants underwent full-body radiologic imaging, goniometric range of motion (ROM) measurements, general performance tests, and kinematic gait analysis. PATIENTS: Nine adults younger than 60 years with a diagnosis of XLH and self-reported musculoskeletal disability, but able to independently ambulate, were selected to participate. Passive ROM and gait analysis were also performed on age-approximated controls to account for differences between individual laboratory instrumentation. RESULTS: Enthesophytes, degenerative arthritis, and osteophytes were found to be consistently bilateral and diffusely present at the spine and synovial joints across participants, with predominance at weight-bearing joints. Passive ROM in adults with XLH was decreased at the cervical spine, hip, knee, and ankle compared to controls. Gait analysis relative to controls revealed increased step width, markedly increased lateral trunk sway, and physical restriction at the hip, knees, and ankle joints that translated into limitations through the gait cycle. CONCLUSIONS: The functional impact of XLH musculoskeletal comorbidities supports the necessity for creating an interprofessional health-care team with the goal of establishing a longitudinal plan of care that considers the manifestations of XLH across the lifespan.

Efficacy, Safety, and Usability of Remifentanil as Premedication for INSURE in Preterm Neonates.

Background: We previously reported a 67% extubation failure with INSURE (Intubation, Surfactant, Extubation) using morphine as analgosedative premedication. Remifentanil, a rapid- and short-acting narcotic, might be ideal for INSURE, but efficacy and safety data for this indication are limited. Objectives: To assess whether remifentanil premedication increases extubation success rates compared with morphine, and to evaluate remifentanil's safety and usability in a teaching hospital context. Methods: Retrospective review of remifentanil orders for premedication, at a large teaching hospital neonatal intensive care unit (NICU). We compared INSURE failure rates (needing invasive ventilation after INSURE) with prior morphine-associated rates. Additionally, we surveyed NICU staff to identify usability and logistic issues with remifentanil. Results: 73 remifentanil doses were administered to 62 neonates (mean 31.6 ± 3.8 weeks' gestation). Extubation was successful in 88%, vs. 33% with morphine premedication (p < 0.001). Significant adverse events included chest wall rigidity (4%), one case of cardiopulmonary resuscitation (CPR) post-surfactant, naloxone reversal (5%), and notable transient desaturation (34%). Among 137 completed surveys, 57% indicated concerns, including delayed drug availability (median 1.1 h after order), rapid desaturations narrowing intubation timeframes and hindering trainee involvement, and difficulty with bag-mask ventilation after unsuccessful intubation attempts. Accordingly, 33% of ultimate intubators were attending neonatologists, versus 16% trainees. Conclusions: Remifentanil premedication was superior to morphine in allowing successful extubation, despite occasional chest wall rigidity and unfavorable conditions for trainees. We recommend direct supervision and INSURE protocols aimed at ensuring rapid intubation.

Sociodemographic disparities in the occurrence of medical conditions among adolescent and young adult Hodgkin lymphoma survivors.

PURPOSE: Hodgkin lymphoma (HL) survivors experience high risks of second cancers and cardiovascular disease, but no studies have considered whether the occurrence of these and other medical conditions differ by sociodemographic factors in adolescent and young adult (AYA) survivors. METHODS: Data for 5,085 patients aged 15-39 when diagnosed with HL during 1996-2012 and surviving ≥ 2 years were obtained from the California Cancer Registry and linked to hospitalization data. We examined the impact of race/ethnicity, neighborhood socioeconomic status (SES), and health insurance on the occurrence of medical conditions (≥ 2 years after diagnosis) and the impact of medical conditions on survival using multivariable Cox proportional hazards regression. RESULTS: Twenty-six percent of AYAs experienced at least one medical condition and 15% had ≥ 2 medical conditions after treatment for HL. In multivariable analyses, Black HL survivors had a higher likelihood (vs. non-Hispanic Whites) of endocrine [hazard ratio (HR) = 1.37, 95% confidence interval (CI) 1.05-1.78] and circulatory system diseases (HR = 1.58, CI 1.17-2.14); Hispanics had a higher likelihood of endocrine diseases [HR = 1.24 (1.04-1.48)]. AYAs with public or no insurance (vs. private/military) had higher likelihood of circulatory system diseases, respiratory system diseases, chronic kidney disease/renal failure, liver disease, and endocrine diseases. AYAs residing in low SES neighborhoods (vs. high) had higher likelihood of respiratory system and endocrine diseases. AYAs with these medical conditions or second cancers had an over twofold increased risk of death. CONCLUSION: Strategies to improve health care utilization for surveillance and secondary prevention among AYA HL survivors at increased risk of medical conditions may improve outcomes.

Pediatric Pharmacists' Participation in Cardiopulmonary Resuscitation Events.

The Pediatric Pharmacy Advocacy Group (PPAG) understands the dilemma and varying factors that many institutions face concerning the routine participation of pharmacists in emergency resuscitation events. Acknowledging these obstacles, the PPAG encourages all institutions to strongly consider creating, adopting, and upholding policies to address pharmacists' participation in cardiopulmonary resuscitation (CPR) as evidenced by the impact pharmacist participation has shown on the reduction of hospital medication error and mortality rates in children. The PPAG advocates that pharmacists be actively involved in the institution's CPR, medical emergency team committees, and preparation of emergency drug kits and resuscitation trays. The PPAG advocates that all institutions requiring a pharmacist's participation in CPR events consider adoption of preparatory training programs. Although the PPAG does not advocate any one specific program, consideration should be taken to ensure that pharmacists are educated on the pharmacotherapy of drugs used in the CPR process, including but not limited to basic life support, Advanced Cardiac Life Support, and Pediatric Advanced Life Support algorithms; medication preparation and administration guidelines; medication compatibility; recommended dosing for emergency medications; and familiarity with the institutional emergency cart.

The Circle-Fit Method Helps Make Reliable Cortical Thickness Measurements Regardless of Humeral Length.

BACKGROUND: Although proximal humerus strength/quality can be assessed using cortical thickness measurements (eg, cortical index), there is no agreement where to make them. Tingart and coworkers used measurements where the proximal endosteum becomes parallel, while Mather and coworkers used measurements where the periosteum becomes parallel. The new circle-fit method (CFM) makes 2 metaphyseal (M1-M2) and 6 diaphyseal (D1-D6) measurements referenced from humeral head diameter (HHD). However, it is unknown whether these locations correlate to humeral length (HL). Accordingly, we asked: (1) Does HHD, Tingart distance, and Mather distance correlate with HL? (2) What is the location of HHD, Tingart distance, and Mather distance as a percentage of HL? and (3) Which CFM D1-D6 locations correlate with Tingart and Mather distances? MATERIALS AND METHODS: Measurements made on cortical thickness (CT) scout views of 19 humeri (ages: 16-73 years) included HHD, distances from the superior aspect of the humerus to proximal Tingart and Mather locations, and HL. RESULTS: Intraclass correlation was excellent for CFM-HHD, poor for Tingart, and moderate for Mather. The CFM-HHD had a stronger correlation to HL than Tingart and Mather. Mean HHD was 15.5% (0.9%) of HL while Tingart was 27.0% (4.1%) and Mather was 23.2% (3.8%). Tingart distance corresponded to D2/D3 CFM locations while the Mather distance was similar to D1/D2. DISCUSSION: The CFM reliably correlates with HL and provides a stronger correlation and less variance between specimens than the Tingart or Mather Methods. CONCLUSIONS: Because the CFM produces reliable percent of HL locations, it should be used to define locations for obtaining biomechanically relevant CT measurements such as cortical index. Stronger correlations of these CFM-based measurements with proximal humerus strength will be important for developing advanced algorithms for fracture treatment.

Population-based birth defects data in the United States, 2010-2014: A focus on gastrointestinal defects.

BACKGROUND: Gastrointestinal defects are a phenotypically and etiologically diverse group of malformations. Despite their combined prevalence and clinical impact, little is known about the epidemiology of these birth defects. Therefore, the objective of the 2017 National Birth Defects Prevention Network (NBDPN) data brief was to better describe the occurrence of gastrointestinal defects. METHODS: As part of the 2017 NBDPN annual report, 28 state programs provided additional data on gastrointestinal defects for the period 2010-2014. Counts and prevalence estimates (per 10,000 live births) were calculated overall and by demographic characteristics for (1) biliary atresia; (2) esophageal atresia/tracheoesophageal fistula; (3) rectal and large intestinal atresia/stenosis; and (4) small intestinal atresia/stenosis. Additionally, we explored the frequency of these malformations co-occurring with other structural birth defects. RESULTS: Pooling data from all participating registries, the prevalence estimates were: 0.7 per 10,000 live births for biliary atresia (713 cases); 2.3 per 10,000 live births for esophageal atresia/tracheoesophageal fistula (2,472 cases); 4.2 per 10,000 live births for rectal and large intestinal atresia/stenosis (4,334 cases); and 3.4 per 10,000 live births for small intestinal atresia/stenosis (3,388 cases). Findings related to co-occurring birth defects were especially notable for esophageal atresia/tracheoesophageal fistula, rectal and large intestinal atresia/stenosis, and small intestinal atresia/stenosis, where the median percentage of non-isolated cases was 53.9%, 45.5%, and 50.6%, respectively. CONCLUSIONS: These population-based prevalence estimates confirm some previous studies, and provide a foundation for future epidemiologic studies of gastrointestinal defects. Exploring the genetic and environmental determinants of these malformations may yield new clues into their etiologies.

Duty to Advocate: Human Papillomavirus Vaccination.

Despite the excellent benefit-to-risk ratio for human papillomavirus (HPV) vaccination and recommendations for its routine use from the Advisory Committee on Immunization Practices (ACIP), significant controversy surrounding HPV vaccination continues to exist. In light of this controversy and continued low rates of vaccination among U.S. adolescents, the Pediatric Pharmacy Advocacy Group (PPAG) endorses the safety and efficacy of HPV vaccination and agrees with ACIP recommendations for protection of the U.S. population against the potentially severe consequences of HPV. The PPAG recommends that all eligible individuals undergo vaccination. We further recommend that pediatric pharmacists participate in the education of patients and their families and serve as advocates for HPV vaccination. This document serves as an update to the 2008 PPAG position statement.1.

Population-based microcephaly surveillance in the United States, 2009 to 2013: An analysis of potential sources of variation.

BACKGROUND: Congenital microcephaly has been linked to maternal Zika virus infection. However, ascertaining infants diagnosed with microcephaly can be challenging. METHODS: Thirty birth defects surveillance programs provided data on infants diagnosed with microcephaly born 2009 to 2013. The pooled prevalence of microcephaly per 10,000 live births was estimated overall and by maternal/infant characteristics. Variation in prevalence was examined across case finding methods. Nine programs provided data on head circumference and conditions potentially contributing to microcephaly. RESULTS: The pooled prevalence of microcephaly was 8.7 per 10,000 live births. Median prevalence (per 10,000 live births) was similar among programs using active (6.7) and passive (6.6) methods; the interdecile range of prevalence estimates was wider among programs using passive methods for all race/ethnicity categories except Hispanic. Prevalence (per 10,000 live births) was lowest among non-Hispanic Whites (6.5) and highest among non-Hispanic Blacks and Hispanics (11.2 and 11.9, respectively); estimates followed a U-shaped distribution by maternal age with the highest prevalence among mothers <20 years (11.5) and ≥40 years (13.2). For gestational age and birth weight, the highest prevalence was among infants <32 weeks gestation and infants <1500 gm. Case definitions varied; 41.8% of cases had an HC ≥ the 10th percentile for sex and gestational age. CONCLUSION: Differences in methods, population distribution of maternal/infant characteristics, and case definitions for microcephaly can contribute to the wide range of observed prevalence estimates across individual birth defects surveillance programs. Addressing these factors in the setting of Zika virus infection can improve the quality of prevalence estimates. Birth Defects Research (Part A) 106:972-982, 2016. © 2016 Wiley Periodicals, Inc.

A quality assessment of reporting sources for microcephaly in Utah, 2003 to 2013.

BACKGROUND: Obtaining accurate microcephaly prevalence is important given the recent association between microcephaly and Zika virus. Assessing the quality of data sources can guide surveillance programs as they focus their data collection efforts. The Utah Birth Defect Network (UBDN) has monitored microcephaly by data sources since 2003. The objective of this study was to examine the impact of reporting sources for microcephaly surveillance. METHODS: All reported cases of microcephaly among Utah mothers from 2003 to 2013 were clinically reviewed and confirmed. The UBDN database was linked to state vital records and hospital discharge data for analysis. Reporting sources were analyzed for positive predictive value and sensitivity. RESULTS: Of the 477 reported cases of microcephaly, 251 (52.6%) were confirmed as true cases. The UBDN identified 94 additional cases that were reported to the surveillance system as another birth defect, but were ultimately determined to be true microcephaly cases. The prevalence for microcephaly based on the UBDN medical record abstraction and clinical review was 8.2 per 10,000 live births. Data sources varied in the number and accuracy of reporting, but a case was more likely to be a true case if identified from multiple sources than from a single source. CONCLUSION: While some reporting sources are more likely to identify possible and true microcephaly cases, maintaining a multiple source methodology allows for more complete case ascertainment. Surveillance programs should conduct periodic assessments of data sources to ensure their systems are capturing all possible birth defects cases. Birth Defects Research (Part A) 106:983-988, 2016. © 2016 Wiley Periodicals, Inc.

"Nonfunctional" Adrenal Tumors and the Risk for Incident Diabetes and Cardiovascular Outcomes: A Cohort Study.

BACKGROUND: Benign adrenal tumors are commonly discovered on abdominal imaging. Most are classified as nonfunctional and are considered to pose no health risk, but some are considered functional because they secrete hormones that increase risk for metabolic and cardiovascular diseases. OBJECTIVE: To evaluate the hypothesis that nonfunctional adrenal tumors (NFATs) increase risk for cardiometabolic outcomes compared with absence of adrenal tumors. DESIGN: Cohort study. SETTING: Integrated hospital system. PARTICIPANTS: Participants with benign NFATs ("exposed"; n = 166) and those with no adrenal tumor ("unexposed"; n = 740), with at least 3 years of follow-up. MEASUREMENTS: Medical records were reviewed from the time of abdominal imaging for development of incident outcomes (hypertension, composite diabetes [prediabetes or type 2 diabetes], hyperlipidemia, cardiovascular events, and chronic kidney disease) (mean, 7.7 years). Primary analyses evaluated independent associations between exposure status and incident outcomes by using adjusted generalized linear models. Secondary analyses evaluated relationships between NFATs and cortisol physiology. RESULTS: Participants with NFATs had significantly higher risk for incident composite diabetes than those without adrenal tumors (30 of 110 [27.3%] vs. 72 of 615 [11.7%] participants; absolute risk, 15.6% [95% CI, 6.9% to 24.3%]; adjusted risk ratio, 1.87 [CI, 1.17 to 2.98]). No significant associations between NFATs and other outcomes were observed. Higher "normal" postdexamethasone cortisol levels (≤50 nmol/L) were associated with larger NFAT size and higher prevalence of type 2 diabetes. LIMITATION: Potential bias in the selection of participants and ascertainment of outcomes. CONCLUSION: Participants with NFATs had a significantly higher risk for diabetes than those without adrenal tumors. These results should prompt a reassessment of whether the classification of benign adrenal tumors as "nonfunctional" adequately reflects the continuum of hormone secretion and metabolic risk they may harbor. PRIMARY FUNDING SOURCE: National Institutes of Health and Doris Duke Charitable Foundation.

Vancomycin dosing in children and young adults: back to the drawing board.

STUDY OBJECTIVE: To compare the likelihood of alternative vancomycin dosing strategies based on weight, height, or body surface area (BSA) in achieving isometric vancomycin area under the serum concentration-time curve (AUC) values across the body size distribution of children and young adults. DESIGN: Maximum a posteriori probability Bayesian (MAP-Bayesian) pharmacokinetic analysis using retrospectively collected medical record data. SETTING: Children's hospital. PATIENTS: A total of 115 patients 1-20 years of age managed outside of the intensive care unit who were treated with vancomycin between May 1, 2011, and August 31, 2012, and had a minimum of two serum vancomycin concentration measurements. MEASUREMENTS AND MAIN RESULTS: Vancomycin dosing and concentration-time information along with demographic and laboratory data related to kidney function estimation were extracted from the patients' medical records. A previously structured one-compartment model was used to derive MAP-Bayesian estimates of pharmacokinetic system parameters for each patient. Post hoc linear and power function regression were used to compare clearance (Cl) and the volume of distribution of the central compartment (Vc) to body size descriptors (weight, height, and BSA). The relationship of the body size descriptor-indexed parameter across the body size distribution was assessed. The AUC from time 0 to 24 hours (AUC24 ) values associated with vancomycin dosing regimens based on weight, height, and BSA were estimated. The 115 patients (56.5% male) had a mean ± SD age, height, and weight of 9.7 ± 5.4 years, 133 ± 32.3 cm, and 38.0 ± 24.2 kg, respectively. Each patient received a minimum of four doses of vancomycin and had two to nine serum vancomycin concentration measurements, for a total of 313 measurements for all patients. Vancomycin Cl was a nonlinear function of weight and a linear-proportionate function of BSA, whereas the volume of distribution of the central compartment (Vc) was a linear-proportionate function of weight. The expected median (5th-95th percentile) AUC24 values with weight-based dosing of vancomycin 60-70 mg/kg/day were 446 (315-834) mg·hour/L and 649 (385-1165) mg·hour/L in patients weighing less than 40 kg (n=72) and those weighing 40 kg or more (n=43), respectively. In contrast, isometric AUC24 values were predicted with BSA-based dosing across the body size distribution. CONCLUSION: BSA-based dosing is more likely than weight-based (mg/kg) dosing of vancomycin to achieve isometric AUC24 values across the body size distribution of children and young adults. Pharmacokinetic studies that compare these two vancomycin dosing strategies in children are clearly needed to validate these findings.