Bio

Clinical Focus

  • General Surgery
  • Pediatric Surgery

Academic Appointments

Professional Education

  • Residency:New York University - School Of Medicine (2006) NY
  • Medical Education:New York University - School Of Medicine (2001) NY
  • Board Certification: Pediatric Surgery, American Board of Surgery
  • Fellowship:University of Montreal (2008) Canada
  • Board Certification: General Surgery, American Board of Surgery (2006)

Contact

    • Tel: (650) 736-9673
  • Pediatric General Surgery 777 Welch Road, Suite J MC 5733 Palo Alto, CA94304
    • Tel: (650) 723-6439
    Fax: (650) 725-5577

Research & Scholarship

Current Research and Scholarly Interests

Investigations of how children's beliefs of health affect their responses to illness.

Teaching

2013-14 Courses

Publications

Journal Articles

  • Effectiveness of a Staged US and CT Protocol for the Diagnosis of Pediatric Appendicitis: Reducing Radiation Exposure in the Age of ALARA RADIOLOGY Krishnamoorthi, R., Ramarajan, N., Wang, N. E., Newman, B., Rubesova, E., Mueller, C. M., Barth, R. A. 2011; 259 (1): 231-239

    Abstract

    To evaluate the effectiveness of a staged ultrasonography (US) and computed tomography (CT) imaging protocol for the accurate diagnosis of suspected appendicitis in children and the opportunity for reducing the number of CT examinations and associated radiation exposure.This retrospective study was compliant with HIPAA, and a waiver of informed consent was approved by the institutional review board. This study is a review of all imaging studies obtained in children suspected of having appendicitis between 2003 and 2008 at a suburban pediatric emergency department. A multidisciplinary staged US and CT imaging protocol for the diagnosis of appendicitis was implemented in 2003. In the staged protocol, US was performed first in patients suspected of having appendicitis; follow-up CT was recommended when US findings were equivocal. Of 1228 pediatric patients who presented to the emergency department for suspected appendicitis, 631 (287 boys, 344 girls; age range, 2 months to 18 years; median age, 10 years) were compliant with the imaging pathway. The sensitivity, specificity, negative appendectomy rate (number of appendectomies with normal pathologic findings divided by the number of surgeries performed for suspected appendicitis), missed appendicitis rate, and number of CT examinations avoided by using the staged protocol were analyzed.The sensitivity and specificity of the staged protocol were 98.6% and 90.6%, respectively. The negative appendectomy rate was 8.1% (19 of 235 patients), and the missed appendicitis rate was less than 0.5% (one of 631 patients). CT was avoided in 333 of the 631 patients (53%) in whom the protocol was followed and in whom the US findings were definitive.A staged US and CT imaging protocol in which US is performed first in children suspected of having acute appendicitis is highly accurate and offers the opportunity to substantially reduce radiation.

    View details for DOI 10.1148/radiol.10100984

    View details for Web of Science ID 000288848800028

    View details for PubMedID 21324843

Conference Proceedings

  • Topical mitomycin-C for the treatment of anal stricture Mueller, C. M., Beaunoyer, M., St-Vil, D. W B SAUNDERS CO-ELSEVIER INC. 2010: 241-244

    Abstract

    Anal stricture is a well-known and feared consequence of anorectal surgery. Daily dilatations are often prescribed in the immediate postoperative period to avoid stricture of the anus. Nonetheless, stricture may still occur and, particularly in older children, may require multiple dilatations under anesthesia. Topical mitomycin-C has been found to be effective in the treatment of strictures at various anatomical locations. In this article, we review our experience with topical mitomycin-C as an adjunct to anal dilatation for children with anal stricture.Cases of children with anal stricture who were treated with a single application of topical mitomycin-C as an adjunct to anal dilatation between 2000 and 2008 were analyzed retrospectively. Anal diameter was measured with Hegar dilators. Cottonoid swabs soaked in mitomycin-C were placed on the anal mucosa for 5 minutes after dilatation. Treatment success was defined by sustained improvement in anal size, decrease in symptoms, parental satisfaction, and need for additional intervention.Ten children with anal stricture who underwent anal dilatation with application of topical mitomycin-C were identified. All children presented with severe constipation. Average increase in anal size after dilatation under sedation was 5.7 mm (+/-3.2 mm). Average improvement in anal diameter on first clinic visit after mitomycin-C application was 3.7 mm. On follow-up, only 1 child required repeated intervention for stricture after treatment with mitomycin-C. No complications were associated with the use of mitomycin-C.All children treated with mitomycin-C showed early improvement in their anal size after dilatation under sedation. A single application of topical mitomycin-C allowed them to retain an increased anal diameter over time and avoid additional dilatations. Furthermore, the application of mitomycin-C in our population was straightforward and safe. Therefore, we advocate its use as an adjunct to anal dilatation under sedation in the treatment of severe anal stricture.

    View details for DOI 10.1016/j.jpedsurg.2009.10.038

    View details for Web of Science ID 000274393800039

    View details for PubMedID 20105611

  • An Interdisciplinary Initiative to Reduce Radiation Exposure: Evaluation of Appendicitis in a Pediatric Emergency Department With Clinical Assessment Supported by a Staged Ultrasound and Computed Tomography Pathway Ramarajan, N., Krishnamoorthi, R., Barth, R., Ghanouni, P., Mueller, C., Dannenburg, B., Wang, N. E. WILEY-BLACKWELL PUBLISHING, INC. 2009: 1258-1265

    Abstract

    In the emergency department (ED), a significant amount of radiation exposure is due to computed tomography (CT) scans performed for the diagnosis of appendicitis. Children are at increased risk of developing cancer from low-dose radiation and it is therefore desirable to utilize CT only when appropriate. Ultrasonography (US) eliminates radiation but has sensitivity inferior to that of CT. We describe an interdisciplinary initiative to use a staged US and CT pathway to maximize diagnostic accuracy while minimizing radiation exposure.This was a retrospective outcomes analysis of patients presenting after hours for suspected appendicitis at an academic children's hospital ED over a 6-year period. The pathway established US as the initial imaging modality. CT was recommended only if US was equivocal. Clinical and pathologic outcomes from ED diagnosis and disposition, histopathology and return visits, were correlated with the US and CT. ED diagnosis and disposition, pathology, and return visits were used to determine outcome.A total of 680 patients met the study criteria. A total of 407 patients (60%) followed the pathway. Two-hundred of these (49%) were managed definitively without CT. A total of 106 patients (26%) had a positive US for appendicitis; 94 (23%) had a negative US. A total of 207 patients had equivocal US with follow-up CT. A total of 144 patients went to the operating room (OR); 10 patients (7%) had negative appendectomies. One case of appendicitis was missed (<0.5%). The sensitivity, specificity, negative predictive value, and positive predictive values of our staged US-CT pathway were 99%, 91%, 99%, and 85%, respectively. A total of 228 of 680 patients (34%) had an equivocal US with no follow-up CT. Of these patients, 10 (4%) went to the OR with one negative appendectomy. A total of 218 patients (32%) were observed clinically without complications.Half of the patients who were treated using this pathway were managed with definitive US alone with an acceptable negative appendectomy rate (7%) and a missed appendicitis rate of less than 0.5%. Visualization of a normal appendix (negative US) was sufficient to obviate the need for a CT in the authors' experience. Emergency physicians (EPs) used an equivocal US in conjunction with clinical assessment to care for one-third of study patients without a CT and with no known cases of missed appendicitis. These data suggest that by employing US first on all children needing diagnostic imaging for diagnosis of acute appendicitis, radiation exposure may be substantially decreased without a decrease in safety or efficacy.

    View details for DOI 10.1111/j.1553-2712.2009.00511.x

    View details for Web of Science ID 000271465000031

    View details for PubMedID 20053244

Stanford Medicine Resources: