Publications by authors named "Abigail K Zamora"

Background: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence-based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi-institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative.

Methods: Data were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019.

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Importance: Necrotizing enterocolitis (NEC) requiring surgical intervention is the most common reason for surgical procedures in preterm neonates. Opioids are used to manage postoperative pain, with some infants requiring methadone to treat physiologic opioid dependence or wean from nonmethadone opioid treatment during recovery.

Objective: To describe postoperative opioid use and methadone treatment for infants with surgically treated NEC and evaluate postoperative outcomes.

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Background: Gabapentin is increasingly used as an off-label, opioid-sparing pain medication in children. We investigated perioperative gabapentin administration and postoperative opioid use in children who underwent appendectomy for perforated appendicitis.

Methods: A retrospective cohort study of healthy children ages 2-18 years undergoing appendectomy for perforated appendicitis from 2014 to 2019 was performed using the Pediatric Health Information System®.

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Background: Central hepatectomy (CH) is an uncommon surgical technique that is an option for resection of centrally located tumors, with the advantage of sparing normal hepatic parenchyma. Few studies have described outcomes in children undergoing CH.

Materials And Methods: An IRB-approved, retrospective chart review of patients who underwent CH at Children's Hospital Los Angeles between 2005 and 2016 was performed.

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Background/purpose: Abdominal lymphatic malformations (LM) are a rare subset of vascular anomaly caused by abnormal development of the lymphatic system. They are classified as macrocystic, microcystic or combination macrocystic and microcystic. Surgical resection, percutaneous sclerotherapy, and medical therapy are all employed to treat these complex and often symptomatic lesions.

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Background: Immunotherapy with anti-disialoganglioside dinutuximab has improved survival for children with high-risk neuroblastoma (NB) when given after induction chemotherapy and surgery. However, disease recurrence and resistance persist. Dinutuximab efficacy has not been evaluated when initiated before primary tumor removal.

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Background: The impact of postoperative opioid use on outcomes for children with perforated appendicitis is unknown.

Methods: A retrospective cohort study was performed using the Pediatric Health Information System database from 2005 to 2015. Children 2 to 18 years with perforated appendicitis who underwent an appendectomy were identified.

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Background: Pleuropulmonary blastoma (PPB) is the most common primary lung cancer in children. While rare, these tumors are highly aggressive. Tumor recurrence and overall survival are dependent on histologic grade and extent of surgical resection.

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Although often successful in acute settings, long-term use of opioid pain medications may be accompanied by waning levels of analgesic response not readily attributable to advancing underlying disease, necessitating dose escalation to attain pain relief. Analgesic tolerance, and more recently opioid-induced hyperalgesia, have been invoked to explain such declines in opioid effectiveness over time. Because both phenomena result in inadequate analgesia, they are difficult to distinguish in a clinical setting.

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Acute and chronic exposure to opioids has been associated with hyperalgesia in both animals and humans. A genetic analysis of opioid-induced hyperalgesia in mice linked the β(2)-adrenergic receptor to mechanical sensitization after opioid exposure. In humans, expansion of the area of mechanical hyperalgesia surrounding an experimentally induced lesion after the cessation of remifentanil infusion is a commonly used model of opioid hyperalgesia (remifentanil-induced postinfusion hyperalgesia, RPH).

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Unlabelled: Some recent studies suggested a role of the endogenous opioid system in modulating opioid-induced hyperalgesia (OIH). In order to test this hypothesis, we conducted a prospective randomized, placebo-controlled, 2-way crossover study in healthy human volunteers. We utilized a well-established model of inducing OIH after a brief exposure to the μ-opioid agonist remifentanil using intradermal electrical stimulation.

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