Patrick R. Johnston

Skeletal Trauma in Child Abuse: Detection with 18F-NaF PET

PURPOSE To evaluate the sensitivity of fluorine 18-labeled sodium fluoride ((18)F-NaF) positron emission tomography (PET) for assessment of skeletal trauma in pediatric patients suspected of having been abused and to compare the diagnostic performance of this examination with that of high-detail skeletal survey. MATERIALS AND METHODS The institutional review board approved this retrospective study and determined that it was in accordance with regulations of HIPAA privacy rule 45, Code of Federal Regulations parts 160 and 164, and that the criteria for waived patient authorization were met. The baseline skeletal survey and PET images obtained in 22 patients younger than 2 years between September 2007 and January 2009 were reviewed. Fourteen patients also underwent follow-up skeletal survey. The PET images were interpreted by two pediatric nuclear medicine physicians. The initially obtained skeletal survey images were interpreted blindly by a pediatric radiologist. A second pediatric radiologist interpreted the follow-up skeletal survey images in conjunction with the baseline survey images and rendered a final interpretation for the 14 patients in whom both baseline and follow-up skeletal survey data were available, which served as the reference standard. RESULTS A total of 156 fractures were detected at baseline skeletal survey, and 200 fractures were detected at PET. Compared with the reference standard (findings in the 14 patients who underwent baseline and follow-up skeletal survey), PET had sensitivities of 85% for the detection of all fractures, 92% for the detection of thoracic fractures (ribs, sternum, clavicle, and scapula), 93% for the detection of posterior rib fractures, and 67% for the detection of classic metaphyseal lesions (CMLs), defined as a series of microfractures across the metaphysis. Compared with the reference standard, baseline skeletal survey had sensitivities of 72% for the detection of all fractures, 68% for the detection of thoracic fractures, 73% for the detection of posterior rib fractures, and 80% for the detection of CMLs. CONCLUSION (18)F-NaF PET had greater sensitivity in the overall detection of fractures related to child abuse than did baseline skeletal survey. (18)F-NaF PET was superior in the detection of rib fractures in particular. Thus, (18)F-NaF PET is an attractive choice for evaluation of suspected child abuse, an application in which high sensitivity is desirable. Because of the lower sensitivity of PET in the detection of CMLs, a characteristic fracture in child abuse, initial radiographic evaluation remains necessary.

Risk Factors for Intestinal Failure in Infants with Necrotizing Enterocolitis: A Glaser Pediatric Research Network Study

OBJECTIVE To determine risk factors for intestinal failure (IF) in infants undergoing surgery for necrotizing enterocolitis (NEC). STUDY DESIGN Infants were enrolled in a multicenter prospective cohort study. IF was defined as the requirement for parenteral nutrition for >or= 90 days. Logistic regression was used to identify predictors of IF. RESULTS Among 473 patients enrolled, 129 had surgery and had adequate follow-up data, and of these patients, 54 (42%) developed IF. Of the 265 patients who did not require surgery, 6 (2%) developed IF (OR 31.1, 95% CI, 12.9 - 75.1, P < .001). Multivariate analysis identified the following risk factors for IF: use of parenteral antibiotics on the day of NEC diagnosis (OR = 16.61, P = .022); birth weight < 750 grams, (OR = 9.09, P < .001); requirement for mechanical ventilation on the day of NEC diagnosis (OR = 6.16, P = .009); exposure to enteral feeding before NEC diagnosis (OR=4.05, P = .048); and percentage of small bowel resected (OR = 1.85 per 10 percentage point greater resection, P = .031). CONCLUSION The incidence of IF among infants undergoing surgical treatment for NEC is high. Variables characteristic of severe NEC (low birth weight, antibiotic use, ventilator use, and greater extent of bowel resection) were associated with the development of IF.

Phosphorylcholine-coated antibiotic tympanostomy tubes: Are post-tube placement complications reduced?

OBJECTIVE To determine if a phosphorylcholine (PC) antibacterial coating on standard Armstrong beveled tympanostomy tubes (TT) reduced the incidence of post-tube placement complications. METHODS A prospective cohort aged 8-51 months received bilateral TTs for otitis media with effusion between July 2002 and February 2004 at a tertiary care pediatric hospital. Seventy children were randomized to receive a PC-coated TT in one ear and an uncoated TT in the other. Otologic examinations at prescribed intervals over two years post-operatively ascertained the status of sequelae. We analyzed the incidence of TT complications: otorrhea, premature extrusion, persistent tympanic membrane perforations, granulation tissue, and ventilation tube lumen obstruction. RESULTS There was no statistical difference in the incidence of any of these sequelae between standard and PC-coated tympanostomy tubes (p>0.05) during the 24-month-follow-up period. Results after 13 months of follow-up may have been affected by patients lost to follow-up and therefore a smaller sample size as the study continued. CONCLUSIONS This study found that there is no statistically significant difference in the incidence of complications between uncoated and PC-coated fluoroplastic Armstrong beveled TTs.

Sensorineural hearing loss in patients with cystic fibrosis

Objective: To determine the prevalence of sensorineural hearing loss (SNHL) in cystic fibrosis (CF) patients and its relationship to antibiotic use. Study Design: Case series with chart review. Setting: Tertiary care pediatric hospital. Subjects and Methods: We reviewed the medical records of CF patients seen in our childrens hospital between March 1994 and December 2007. Data collected included patient demographics, audiograms, tympanograms, genotype, and use of potentially ototoxic antibiotics. Results: Seven of 50 (14%) patients had SNHL. Three percent of patients who received ≤10 courses of intravenous aminoglycosides had SNHL versus 43 percent of those who received >10 courses (P < 0.01). No patients who received five or fewer courses of nasal irrigation with aminoglycosides had SNHL versus 23 percent of those who received more than five courses (P < 0.05). Nine percent of patients who received five or fewer courses of macrolides had SNHL versus 60 percent of those who received more than five courses (P = 0.079). Conclusion: CF patients receiving aminoglycosides are at high risk for developing SNHL.

HIV prevention for injection drug users in China and Vietnam: Policy and research considerations

Abstract A pattern of serious injection drug user (IDU) driven HIV epidemics in Asia, with emerging evidence of generalization through heterosexual transmission, indicates the need for interventions focusing on both drug- and sex-related risk reduction. In a cross-border HIV prevention project for IDUs in northern Vietnam and southern China, peer educators disseminated risk reduction information to IDUs in the community and provided 20,000–25,000 sterile needles/syringes and 4,000–6,000 condoms per month. Since implementation of these interventions, the frequency of both injecting and sexual risk behaviours fell significantly, HIV prevalence among IDUs declined or stabilized, and HIV incidence dropped. There is official support for harm reduction interventions in both countries but this appears precarious in view of persistently powerful political and financial support for a law enforcement approach. Moreover, the simultaneous pursuit of inconsistent policies can have negative effects on the implementation of interventions. A harmonized and consistent policy environment is needed. Most of the evidence for efficacy of community-based HIV prevention comes from the developed world, but well-designed evaluations of such interventions in Asia and elsewhere in the developing world would have a better chance to influence policy decisions there. A synergistic approach to research, policy development, and service delivery is best calculated to achieve positive results in the struggle against HIV/AIDS in developing countries.

Comparison of Postoperative Pain in Pediatric Patients Undergoing Coblation Tonsillectomy versus Cautery Tonsillectomy

Objective. To compare postoperative pain scores between monopolar electrocautery and coblation subcapsular tonsillectomy. Study Design. Prospective double-blind randomized study. Setting. Tertiary care children’s hospital. Subjects and Methods. Between December 2004 and April 2008, 61 children, ages 4 to 20 years (mean age, 10 years; SD, 4 years), were randomized to have one tonsil removed by electrocautery and the other tonsil removed by coblation. Subjects used the FACES scale to rate pain on each side immediately postoperatively, 2 days postoperatively, and 2 weeks postoperatively. Postoperative hemorrhage was also tracked. Results. Coblation tonsillectomy resulted in statistically less pain than electrocautery immediately after surgery, but this difference was not clinically significant. Conclusions. Pediatric pain is similar following monopolar electrocautery or coblation subcapsular tonsillectomy.

Unilateral Subtalar Coalition: Contralateral Sustentaculum Tali Morphology

PURPOSE To measure and compare the dimensions of the sustentaculum tali (ST) in pediatric patients with unilateral subtalar coalition to determine if the contralateral side has altered morphology. MATERIALS AND METHODS The institutional review board approved this study, which was HIPAA compliant. Informed consent was waived. Radiology records were reviewed to identify 35 patients with unilateral subtalar coalition undergoing computed tomography (CT) (21 male, 14 female; mean age, 14.54 years) and 33 control patients with triplane fracture (21 male, 12 female; mean age, 13.48 years). CT images were reviewed, and reformatted images through the subtalar joint (on the side opposite the coalition) were created. Anteroposterior measurements of the middle facet (MF) and the ST were recorded by two observers with electronic calipers. The MF/ST ratio and the ST length extending posterior to the MF were calculated. Measurements between groups were compared by using Wald tests based on linear regressions. Inter- and intraobserver variabilities were determined by means of a component of variance model. RESULTS The lengths of the MF and ST for the study and control groups were 12.86 and 16.82 mm (P < .001) and 23.83 and 22.06 mm (P = .053), respectively. Intra- and interobserver correlations for both measurements were 0.94 and 0.92 and 0.86 and 0.77, respectively. MF/ST ratio was 0.54 versus 0.76 (P < .001), and ST length extending posterior to the MF was 10.97 versus 5.24 mm (P < .001). CONCLUSION The MF is smaller and the ST extends further beyond the MF in patients with a contralateral subtalar coalition than in control patients. The morphology of the ST may provide insight into the origins and development of coalitions.

The special case of the 2 × 2 table: asymptotic unconditional McNemar test can be used to estimate sample size even for analysis based on GEE

OBJECTIVES Aligning the method used to estimate sample size with the planned analytic method ensures the sample size needed to achieve the planned power. When using generalized estimating equations (GEE) to analyze a paired binary primary outcome with no covariates, many use an exact McNemar test to calculate sample size. We reviewed the approaches to sample size estimation for paired binary data and compared the sample size estimates on the same numerical examples. STUDY DESIGN AND SETTING We used the hypothesized sample proportions for the 2 × 2 table to calculate the correlation between the marginal proportions to estimate sample size based on GEE. We solved the inside proportions based on the correlation and the marginal proportions to estimate sample size based on exact McNemar, asymptotic unconditional McNemar, and asymptotic conditional McNemar. RESULTS The asymptotic unconditional McNemar test is a good approximation of GEE method by Pan. The exact McNemar is too conservative and yields unnecessarily large sample size estimates than all other methods. CONCLUSION In the special case of a 2 × 2 table, even when a GEE approach to binary logistic regression is the planned analytic method, the asymptotic unconditional McNemar test can be used to estimate sample size. We do not recommend using an exact McNemar test.

The distal tibial classic metaphyseal lesion: medial versus lateral cortical injury

BackgroundThe distal tibia is a common location for the classic metaphyseal lesion (CML). Prior radiologic-pathologic studies have suggested a tendency for medial, as opposed to lateral, cortical injury with the CML, but there has been no formal study of the geographic distribution of this strong indicator of abuse.ObjectiveThis study compares medial versus lateral cortical involvement of distal tibial CMLs in a clinical cohort of infants with suspected abuse.Materials and methodsReports of 1,020 skeletal surveys performed for suspected abuse (July 2005-June 2016) were reviewed. Twenty-six distal tibial CMLs (14 unilateral, 6 bilateral) with anteroposterior (AP) and lateral projections on the initial skeletal survey and at least an AP view on the follow-up survey were identified in 20 infants. Two blinded pediatric radiologists determined if the medial and/or lateral margins of the distal tibial metaphysis were involved by the CML.ResultsAverage interreader absolute agreement and kappa scores were 0.69-0.90 and 0.45-0.72, respectively. Average intrareader absolute agreement and kappa scores were 0.65-0.88 and 0.44-0.57, respectively. Analyses showed that the distal tibial CML almost always involved the medial cortical margin (reader 1=89%, reader 2=88%, pooled=89%) and the fracture infrequently involved the lateral cortical margin (reader 1=12%, reader 2=38%, pooled=26%). The percentage point difference between fracture involvement in medial and lateral margins was statistically significant from zero (P<0.001).ConclusionThe distal tibial CML is most often encountered medially; lateral involvement is uncommon. This observation should help guide the radiologic diagnosis and could have implications for understanding the biomechanics of this distinctive injury.

Response to Swanson et al.

We appreciate the comments of Swanson et al. regarding our findings. They raise the challenging question as to whether premature infants at risk for necrotizing enterocolitis (NEC) with a focal area of perforation have a disease entity that is distinct from NEC. This has long been a subject of debate among physicians caring for such patients. We acknowledge the extensive work by Swanson and colleagues contending that spontaneous intestinal perforation (SIP) is a unique disease entity. Our study was not designed to address this issue.