Colin A. Martin

Hirschsprung disease and fecal incontinence: diagnostic and management strategies.

PURPOSE Ideally, fecal incontinence after operative management for Hirschsprung disease should not occur. If it does, it presents a formidable challenge. The purpose of this study was to describe the causes of fecal incontinence and present our algorithm for its treatment. METHODS We reviewed 68 patients with Hirschsprung disease and fecal incontinence referred to us after surgery at other institutions. Patients were evaluated by contrast enema and by an examination under anesthesia to look specifically for the integrity of the anal canal. They were designated as having a dilated colon and constipation or a nondilated colon and a tendency to diarrhea based on their stooling pattern and the appearance of the contrast enema. Medical management was started that included laxatives for those patients with a dilated colon and constipation. For those with a nondilated colon and tendency to diarrhea, the management included loperamide, pectin, and a special dietary regimen (constipating diet, 3 meals per day, and no snacks). Those patients who responded to medical management were retrospectively considered to have been pseudoincontinent. Those who did not respond were considered truly incontinent. The truly incontinent group was treated with enemas alone for those with a dilated colon, or enemas, loperamide, pectin, and a constipating diet for those with a nondilated colon and tendency to diarrhea. RESULTS Fifty-six patients had true incontinence and 12 had pseudoincontinence. Of the true incontinent group, 27 had a dilated colon and 29 had a nondilated colon. Five of these patients had a damaged or absent anal canal (anastomosis at the anal skin) and all of them had true incontinence. In the dilated colon group with true incontinence, 23 (85%) patients were clean after treatment. In the nondilated colon group with true incontinence, 23 (79%) were successfully treated. All patients in the pseudoincontinent groups had no soiling after treatment. Of 55 in the truly incontinent group, 39 (70%) had had an endorectal (Soave type) pull-through. CONCLUSION Fecal incontinence after operative management of Hirschsprung disease represents a serious problem. Poor surgical technique may be a contributing factor in some of the cases. Successful management depends on the appropriate evaluation, which determines whether the incontinence is true or pseudo, and the type of colon the patient has. Each category can be well treated, leading most of the time to a clean child.

Transanal rectosigmoid resection for severe intractable idiopathic constipation

INTRODUCTION Idiopathic constipation is a source of significant morbidity in children. A subset of patients is refractory to medical therapy and requires surgical intervention. We present a novel surgical technique for the management of these patients. METHODS We reviewed the records of 288 patients with severe idiopathic constipation and soiling. Patients who were refractory to medical management and had a megarectosigmoid underwent a transanal full-thickness rectosigmoid resection with a primary colo-anal anastomosis. RESULTS Fifteen patients underwent a transanal rectosigmoid resection. The preoperative contrast enema demonstrated an enormously dilated rectosigmoid in 14. An average of 43 cm (range, 8-98 cm) of rectosigmoid was resected. Of 14 patients with more than 3 months of follow-up, the preoperative laxative dose was 68 mg of senna/d (range, 52-95 mg), which decreased to 8.6 mg postoperatively (P < .001). Nine patients are clean without soiling, 1 is more prone to diarrhea, but is clean. Two patients soil occasionally, but are noncompliant, and 2 were lost to follow-up. CONCLUSION Transanal rectosigmoid resection for medically intractable idiopathic constipation resulted in a dramatic reduction or elimination in laxatives use while preserving continence. It is a useful alternative to surgical options such as other colonic resections, antegrade enemas, and stomas.

Alarming trends in the improper use of motor vehicle restraints in children : implications for public policy and the development of race-based strategies for improving compliance

PURPOSE Little is known regarding the patterns of appropriate restraint use among minority children involved in motor vehicle collisions. The purpose of this study was to characterize patterns of restraint use among children hospitalized after motor vehicle collision and to examine the effects of race and socioeconomic status on compliance. METHODS All children admitted to our level I trauma center over a 10-year period were identified. Patterns of appropriate restraint use were compared between African American (AA) and white children. Compliance was also compared between children insured with Medicaid (as a surrogate for socioeconomic status) and those with private insurance coverage. RESULTS One thousand two hundred sixty-eight patients were included with an overall restraint use of 44.8% with only 20.3% restrained properly. Compared with white children, AAs were significantly less likely to be properly restrained (12.7% vs 22.2%, P < .001) or to be restrained by any means (28.8% vs 48.7%, P < .001). The greatest disparity between groups was observed in the use of car seats (16.0% vs 47.4%, P < .001). Medicaid patients were less likely to be restrained compared with those with commercial insurance (40.6% vs 48.3%, P = .022); however, race remained a significant predictor of noncompliance after controlling for the effect of insurance status. CONCLUSIONS These data demonstrate an alarming trend because nearly 80% of all children in our study were improperly restrained. Marked disparities in compliance were observed in the AA population even after controlling for insurance coverage. Future studies will need to further characterize the complex interplay between race and socioeconomic status with proper restraint use.

Despite overall low pediatric head injury mortality, disparities exist between races

BACKGROUND To continually improve quality of care, it is important for centers caring for children with head injury to evaluate their overall outcome and that among diverse patient groups. METHODS Data on children with head injuries were extracted from the National Trauma Data Bank of the American College of Surgeons and our local trauma registry. Unadjusted mortality, as well as stratified analysis and logistic regression modeling, was used to evaluate overall and race-specific mortality. RESULTS There were 13,363 children in the National Trauma Data Base and 3111 in our database included. Our overall mortality rate compared favorably with the national data (3.2% vs 6.8%, P < .05). Our local data, however, showed a significant difference in mortality between white and African American (AA) children (2.2% vs 5.3%, P < .05), which was not identified in the national data. After stratification, the disparities by race persisted. Finally, multivariate regression modeling revealed that AA race was an independent predictor of mortality among our patient population, with an odds ratio of 3.1 (95% confidence interval, 1.2-7.8). CONCLUSION Despite excellent outcomes for children with head injuries, we have uncovered unsettling inequities between AA and white children. These findings support the need to evaluate outcomes among specific groups to identify disparities that require further careful investigation.

Intestinal resection induces angiogenesis within adapting intestinal villi

PURPOSE Adaptive growth of the intestinal mucosa in response to massive gut loss is fundamental for autonomy from parenteral nutrition. Although angiogenesis is essential for cellular proliferation in other tissues, its relevance to intestinal adaptation is unknown. We tested the hypothesis that resection-induced adaptation is associated with new blood vessel growth. METHODS Male C57Bl/6 mice underwent either a 50% small bowel resection or a sham (transection and reanastomosis) operation. After 1, 3, or 7 days, capillary density within the intestinal villi was measured using confocal microscopy. A messenger RNA reverse-transcriptase polymerase chain reaction (RT-PCR) array was used to determine angiogenic gene expression during adaptation. RESULTS Mice that underwent small bowel resection had a significantly increased capillary density compared to sham-operated mice at postoperative day 7. This morphological alteration was preceded by significant alterations in 5 candidate genes at postoperative day 3. CONCLUSION New vessel blood growth is observed in the adapting intestine after massive small bowel loss. This response appears to follow rather than initiate the adaptive alterations in mucosal morphology that are characteristic of adaptation. A better understanding of this progress and the signaling factors involved may improve therapeutic options for children with short gut syndrome.

Race Disparities in Wilms Tumor Incidence and Biology

BACKGROUND Wilms tumor (WT) is thought to arise in children of Black African ancestry with greater frequency than in Whites. To clarify the biological basis for race disparities in WT, we first verified that Black children residing in Tennessee have an increased incidence of WT, and second, established molecular profiles in WT that are specific to race. MATERIALS AND METHODS To assess race disparities in WT epidemiology, the Tennessee Cancer Registry (TCR) was queried for all in-state patients less than 20 y of age and registered between 1999 and 2008. To explore race disparities in WT biology, six Black and four White WT specimens acquired in Tennessee were analyzed using imaging mass spectrometry (IMS). RESULTS TCR data show that Black children are over-represented among WT patients (29%) relative to all other childhood cancers (18.5%; P = 0.01). WT ranked the fifth most common cancer diagnosis among Blacks, but ninth among Whites. The diagnosis of WT occurred 79% more frequently among Blacks (n = 28) than Whites (n = 69; P = 0.01), and proportionally more Blacks tended to present with distant disease. Although overall survival from WT was not statistically different between Blacks (92.9%) and Whites (94.0%), Black males showed the lowest survival (85%; P = 0.21). IMS analysis identified peptide spectra from both WT blastema and stroma that independently classify specimens according to race with greater than 80% accuracy. CONCLUSIONS In Tennessee, Black children appear more susceptible than Whites to develop WT. Race-specific molecular profiles can be determined that may help to clarify pathways of Wilms tumorigenesis and the biological basis for race disparities in WT incidence and biology.

Race disparities in firearm injuries and outcomes among Tennessee children

PURPOSE The aim of this study was to identify race and socioeconomic factors associated with worse outcomes among Tennessee children who sustain firearm injuries. METHODS We queried our institutional pediatric trauma registry and the Davidson County Regional Medical Examiner database for children ages 15 years and younger who sustained firearm injuries between July 1998 and July 2010. Descriptive statistics and logistic regression modeling were used to analyze demographic data, circumstance of injury (unintentional or intentional), odds of death, and characteristics of zip codes (total population, race distribution, and median income) where injuries occurred. RESULTS One hundred eighty-eight children (median age, 13.2 years; range, 1.1-15.8 years) sustained a firearm injury and were either admitted to our institution or were referred directly to the medical examiner. More whites (n = 109, or 58%) sustained a firearm injury than blacks (n = 79, or 42%), but blacks were overrepresented 2.5-fold more compared with the general Tennessee population. Fifty-four children (29%) died, of whom 35 (65%) were black and 19 (35%) were white (P < .001). Ninety-three children sustained unintentional firearm injuries, and 84 were intentional (n = 67, assault; n = 17, suicide). When data were stratified by intent, 67% of blacks and 12% of whites were assaulted (P < .001). After controlling for age and intent, black children were 4 times more likely to die of firearm injuries than whites (P = .008; 95% confidence interval, 1.4-11.3). CONCLUSION In a sample of firearm-injured Tennessee children, blacks were notably overrepresented and far more likely to die than whites. Using zip code data will help to establish firearm injury prevention programs specific to disparate populations and to reduce both violent and accidental childhood firearm injuries.

Lessons learned: optimization of a murine small bowel resection model

Abstract Purpose Central to the use of murine models of disease is the ability to derive reproducible data. The purpose of this study was to determine factors contributing to variability in our murine model of small bowel resection (SBR). Methods Male C57Bl/6 mice were randomized to sham or 50% SBR. The effect of housing type (pathogen-free vs standard housing), nutrition (reconstituted powder vs tube feeding formulation), and correlates of intestinal morphology with gene expression changes were investigated. Multiple linear regression modeling or 1-way analysis of variance was used for data analysis. Results Pathogen-free mice had significantly shorter ileal villi at baseline and demonstrated greater villus growth after SBR compared to mice housed in standard rooms. Food type did not affect adaptation. Gene expression changes were more consistent and significant in isolated crypt cells that demonstrated adaptive growth when compared with crypts that did not deepen after SBR. Conclusion Maintenance of mice in pathogen-free conditions and restricting gene expression analysis to individual animals exhibiting morphologic adaptation enhances sensitivity and specificity of data derived from this model. These refinements will minimize experimental variability and lead to improved understanding of the complex process of intestinal adaptation.

Resection-induced intestinal adaptation and the role of enteric smooth muscle

BACKGROUND Intestinal adaptation after massive small bowel resection (SBR) involves all layers of the bowel wall. Most prior work has focused on changes that occur in the intestinal mucosa. However, the contribution of the underlying intestinal smooth muscle (ISM) to the overall adaptation response remains unclear. METHODS Male C57BL/6 or waved-2 (diminished activity of the epidermal growth factor receptor) mice underwent a 50% proximal SBR or sham operation, and the remnant ileum was harvested 3, 7, and 28 days. Markers of adaptation (villus height, bowel length, circumference, and ISM thickness) and ISM proliferation were recorded. Contractility was measured by attaching the distal ileum to strain gauge transducers and exposed to varying doses of carbachol. RESULTS Intestinal smooth muscle thickness was unchanged at any given time-point after resection; however, the bowel caliber and length were increased, and augmented rates of ISM proliferation were identified. Contractility was increased at 7 days after SBR. Waved-2 mice demonstrated minimal proliferation or intestinal lengthening in response to SBR. CONCLUSION Compared with resection-induced thickening of the mucosa, proliferative changes in the ISM are unique and primarily affect bowel caliber, length, and contractility. Epidermal growth factor receptor signaling appears to play a significant role in adaptation of the ISM cellular compartment.

Severity of head computed tomography scan findings fail to explain racial differences in mortality following child abuse.

INTRODUCTION Differences in head injury severity may not be fully appreciated in child abuse victims. The purpose of this study was to determine if differential findings on initial head computed tomography (CT) scan could explain observed differential outcome by race. METHODS We identified 164 abuse patients from our trauma registry with an Injury Severity Score (ISS) > or = 15. Their initial head CT scan was graded from 1 to 4 (normal to severe). Statistical analysis was performed to asses the correlation between race, head CT grade, Glasgow Coma Scale (GCS) score, and mortality. RESULTS Overall mortality was 17%: 11% for white children, 32% for African-American children (P < .05). In review of the head CT scans there was no difference by race in types of injuries or head CT grade. Using a multivariate regression model, African-American race remained an independent risk factor for mortality with an odd ratio of 4.3 (95% confidence interval [CI] 1.6-11.5). CONCLUSION African-American children had a significantly higher mortality rate despite similar findings on initial head CT scans. Factors other than injury severity may explain these disparate outcomes.