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Dive into the research topics where Manuel P. Meza is active.

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Featured researches published by Manuel P. Meza.


Surgery | 1997

Management of blunt splenic trauma: significant differences between adults and children.

Melissa Powell; Anita P. Courcoulas; Mary J. Gardner; James M. Lynch; Brian G. Harbrecht; Anthony O. Udekwu; Timothy R. Billiar; Michael P. Federle; James V. Ferris; Manuel P. Meza; Andrew B. Peitzman

BACKGROUND Although highly successful in children, nonoperative management of blunt splenic injury in adults is less defined. The purpose of this study was to determine whether mechanism of injury, grade of splenic injury, associated injuries, and pattern of injury differ between adults and children (younger than 15 years of age). METHODS Four hundred eleven patients (293 adults and 118 pediatric patients) with blunt splenic injury were admitted to an affiliated adult/pediatric trauma program from 1989 to 1994. Computed tomography (CT) scans were interpreted in a blinded fashion. Mechanism of injury was significantly different for adults versus children (p < 0.05): motor vehicle crash (66.9% versus 23.7%), motorcycle (8.8% versus 0.8%), sports (2.4% versus 16.9%), falls (8.8% versus 25.4%), pedestrian/automobile (4.4% versus 11.0%), bicycle (1.4% versus 9.3%), and other (7.3% versus 12.7%). RESULTS Higher injury severity scores, lower Glasgow Coma Scales, and higher mortality indicated that the adults were more severely injured than the children. Fifty-nine percent of the adults and 7% of the children required immediate laparotomy for splenic injury. Both CT grade and quantity of blood on CT predicted the need for exploration in adults but not in children. An injury severity score above 15 and high-energy mechanisms correlated with the need for operative intervention. CONCLUSIONS Rather than children simply being physically different, they are injured differently than adults, hence the high rate of nonoperative management.


Journal of Trauma-injury Infection and Critical Care | 2004

Contrast extravasation predicts the need for operative intervention in children with blunt splenic trauma.

Benedict C. Nwomeh; Evan P. Nadler; Manuel P. Meza; Kerry Bron; Barbara A. Gaines; Henri R. Ford

BACKGROUND Although the presence of a contrast blush (CB) on computed tomographic (CT) scan is associated with an increased failure rate of nonoperative management in adults with blunt splenic injury, little information is available for the pediatric population, where nonoperative management is the standard of care. Our aim was to determine whether the finding of CB on CT scan could predict failure of nonoperative therapy in children with blunt splenic injury. METHODS A retrospective analysis of 343 patients admitted with blunt splenic injury to our Level I pediatric trauma center over a 7-year period was performed. All CT scans were reviewed by a radiologist who was blinded to the patient outcome. We excluded 127 patients who either underwent immediate laparotomy without a CT scan or whose CT scans were unavailable at the time of this review. We divided the patients into two groups on the basis of the presence or absence of CB on the updated reading of the CT scan. Demographic variables analyzed included age, sex, mechanism of injury, Injury Severity Score, Glasgow Coma Scale score, initial hemoglobin and hematocrit, and emergency department pulse rate and systolic blood pressure. Outcome measures compared include length of stay, length of intensive care unit stay, the need for splenic intervention, and mortality. Continuous variables were compared using Students t test for normally distributed data and the Mann-Whitney test for skewed data. Categorical data were compared using chi2 analysis or Fishers exact test. Statistical significance was assigned to values of p < 0.05. RESULTS Among the study population (N = 216), 27 patients (12.5%) had CB on CT scan. Patients with CB had significantly lower hematocrit (p = 0.0004) and required operative intervention more frequently than those without CB (22% vs. 4%;p = 0.0008). Among patients with CB, mean pulse rate at presentation was higher in those that required splenic intervention (SI) (129 +/- 20.1) compared with those who underwent successful nonoperative therapy (100.4 +/- 23.1; p = 0.01). Only grade V injuries correlated with the need for laparotomy. CONCLUSION Children with blunt splenic injury who have CB on CT scan are more likely to require SI than those without CB. However, because the majority of patients with CB did not require SI, in the absence of hemodynamic instability, this finding may be insufficient to determine the need for SI. CB is a specific marker of active bleeding that may predict the need for early splenic intervention in a specific subset of patients at presentation.


Pediatric Radiology | 2000

Intrahepatic chemoembolization in unresectable pediatric liver malignancies.

Christopher M. Arcement; Richard Towbin; Manuel P. Meza; David A. Gerber; Robin Kaye; George V. Mazariegos; Brian I. Carr; Jorge Reyes

Objective. To determine the effectiveness of a new miltidisciplinary approach using neoadjuvant intrahepatic chemoembolization (IHCE) and liver transplant (OLTx) in patients with unresectable hepatic tumors who have failed systemic chemotherapy.¶Materials and methods. From November 1989 to April 1998, 14 children (2–15 years old) were treated with 50 courses of intra-arterial chemotherapy. Baseline and post-treatment contrast-enhanced CT and alpha-fetoprotein levels were performed. Seven had hepatoblastoma, and 7 had hepatocellular carcinoma (1 fibrolamellar variant). All patients had subselective hepatic angiography and infusion of cisplatin and/or adriamycin (36 courses were followed by gelfoam embolization). The procedure was repeated every 3–4 weeks based on hepatic function and patency of the hepatic artery.¶Results. Six of 14 children received orthotopic liver transplants (31 courses of IHC). Pretransplant, 3 of 6 showed a significant decrease in alpha-fetoprotein, while only 1 demonstrated a significant further reduction in tumor size). Three of 6 patients are disease free at this time. Three of 6 patients died of metastatic tumor 6, 38, and 58 months, respectively post-transplant. One of 14 is currently undergoing treatment, has demonstrated a positive response, and is awaiting OLTx. Three of 14 withdrew from the program and died. Four of 14 patients developed an increase in tumor size, developed metastatic disease, and were not transplant candidates. Two hepatic arteries thrombosed, and one child had a small sealed-off gastric ulcer as complications of intrahepatic chemoembolization.¶Conclusion. The results of intrahepatic chemoembolization are promising and suggest that some children who do not respond to systemic therapy can be eventually cured by a combination of intrahepatic chemoembolization orthotopic liver transplant. Alpha-fetoprotein and cross-sectional imaging appear to be complementary in evaluating tumor response. IHCE does not appear to convert an anatomically unresectable lesion to a candidate for partial hepatectomy.


Journal of Pediatric Surgery | 1997

Computed tomography grade of splenic injury is predictive of the time required for radiographic healing

James M. Lynch; Manuel P. Meza; Beverly Newman; Mary J. Gardner; Craig T. Albanese

It is largely unknown when a child who has suffered a splenic laceration can return to full unrestricted activity. The purpose of this prospective study is to establish whether the grade of splenic injury is predictive of the length of time required for radiographic healing, and to determine whether there are any adverse long-term sequelae after resumption of unlimited activity. Sixty-nine patients underwent successful nonoperative management (NOM) of computed tomography (CT)-documented splenic injury over a 4-year period. Fifty-eight patients completed follow-up. Mean age was 9.8 years (range, 1 to 17) and mean injury severity score (ISS) was 14.4 (range, 4 to 38). Mechanisms of injury were motor vehicle accident (n = 11), motor vehicle pedestrian (n = 5), falls (n = 13), bike crashes (n = 12), sports (n = 8), all-terrain vehicle (n = 4), and horse (n = 5). The CT-documented injury was identified by discharge ultrasound scan (US) in all cases. There were no long-term complications. Mean time to US healing in grade I (n = 9), II (n = 26), III (n = 19), IV (n = 4) injuries was 3.1, 8.2, 12.1, and 20.7 weeks, respectively. P values were significant (P < .01) in all cases when compared with the next lower injury grade. The time to radiographic healing is directly proportional to the severity of the splenic injury. There was excellent correlation between the initial CT scan and identification of the injury on the discharge US. No long-term complications leg, delayed splenic rupture, splenic pseudocyst) were seen in this study. Pediatric patients who have suffered splenic injury can safely return to full unrestricted activity when the US documents healing.


Journal of Pediatric Surgery | 1996

Intestinal stricture following seat belt injury in children

James M. Lynch; Craig T. Albanese; Manuel P. Meza; Eugene S. Wiener

The most commonly reported intestinal injury from seat belts in children is perforation. A rarely reported late sequela following this type of injury is posttraumatic intestinal stricture (PTIS). A review of the literature reveals a common clinical pattern of presentation in children and adults but an apparent difference in the pathophysiologic mechanism between the pediatric and adult patient. Recently, we treated two children with PTIS. Each case is discussed, and a pathophysiological mechanism for this injury in children is proposed. Recommendations are made for the evaluation and treatment of these uncommon complications of seat belt-related blunt intestinal injury.


Pediatric Radiology | 1998

Left mainstem bronchial narrowing: a vascular compression syndrome?

R. G. Hungate; Beverly Newman; Manuel P. Meza

Background and objective. Vascular compression of the left mainstem bronchus (LMSB) between the descending aorta (DA) and pulmonary artery (PA) has been suggested as a cause for LMSB narrowing in children. These anatomic relationships have not been compared with those in children with a normal LMSB. Materials and methods. We undertook a retrospective review of the medical and radiologic records of 10 symptomatic young children (1–19 months, 5 boys, 5 girls) with MR demonstration of LMSB narrowing and compared them to 40 young children without great vessel or bronchial abnormality on MR (1 week–19 months, 28 boys, 12 girls). Chest MR evaluation included assessment of airway and great vessel anatomy with specific attention to the course of the LMSB and its relationship to the adjacent DA and PA. The position of the DA in relation to the spine was carefully evaluated. Results. Five children had focal and five had diffuse LMSB narrowing. DA position at the level of the crossing LMSB: in 40 % of symptomatic children the DA was located in front of the adjacent vertebral body; in 40 %, 1/2–3/4 and in 20 % 1/4–1/2 of the circumference of the DA was located anterior to the spine. In the control group, the DA was prespinal in 10 %, with a trend toward a more paraspinal location of the DA. The trend toward a difference in position of the DA between symptomatic and control patients was statistically significant (P < 0.05). DA position was not related to age (up to 19 months). At the level where the LMSB crossed the DA, a segment of the PA was located anterior to the LMSB, more often the right PA (RPA) or pulmonary bifurcation in symptomatic children and the left PA (LPA) in controls. No correlation was apparent between length of LMSB narrowing and DA or PA position. Chest radiographic abnormalities, when present, were subtle. Excellent MR/bronchoscopic correlation of LMSB narrowing was found in nine of the ten symptomatic children. One child underwent posterior aortopexy and ligation of the ligamentum arteriosum. Conclusion. LMSB narrowing is well-defined by MR imaging. While a prespinal position of the DA occurs in some children as a normal variant, it is more common and more marked in children with LMSB narrowing. Vascular compression of the LMSB between an anteriorly positioned DA and the pulmonary artery appears to be important in children with symptomatic LMSB narrowing.


Pediatric Surgery International | 2005

Mesenteric inflammatory pseudotumor as a cause of abdominal pain in a teenager: presentation and literature review

Kevin G. Vaughan; Abdulhameed Aziz; Manuel P. Meza; David J. Hackam

Inflammatory pseudotumor (IP) is an unusual cause of chronic abdominal pain in children. The management of these lesions is complicated by controversies surrounding their appropriate classification and the numerous alternate names with which they are described. Successful treatment requires careful radiologic and pathologic evaluation to distinguish IPs from other lesions, along with complete surgical resection. We present the case of a 15-year-old boy with IP and review the literature in an attempt to simplify the description of these tumors.


Pediatric Radiology | 1996

Perflubron as a gastrointestinal MR imaging contrast agent in the pediatric population

George S. Bisset; K. H. Emery; Manuel P. Meza; Nancy Rollins; S. Don; J. S. Shorr

Objective. To evaluate the safety and efficacy of orally administered perflubron for bowel recognition on MR imaging in a pediatric population.Materials and methods. A multicenter trial evaluated 39 pediatric subjects before and after ingestion of perflubron with T1−, proton-density, and T2-weighted sequences through the abdomen and/or pelvis. Post-contrast images were compared with pre-contrast images. Safety was evaluated through assessment of adverse events, clinical laboratory parameters, and vital signs.Results. With regard to efficacy analysis, improvement in the percent of bowel darkened was observed for 85 % of the subjects on T1-weighted images and for 95% of the subjects on proton-density and T2-weighted images. For images of the abdominal region, the percent of bowel darkened was improved for 90–92 % of the subjects across pulse sequences. Improvement rates for the images of the pelvic region ranged from 71 % to 100 %. For at least 75 % of the subjects, proton-density and T2-weighted images of the body and tail of the pancreas, left lobe of the liver, mesenteric fat, and pathological tissue were improved relative to predosing images. Twenty-three percent of the subjects experienced some adverse effects, most of which were minor and related to the digestive system. Clinical laboratory and vital sign evaluations revealed no trends associated with the administration of perflubron.Conclusion. Perflubron is a relatively safe and effective gastrointestinal MR contrast agent in the pediatric population.


Pediatric Surgery International | 2005

An unusual cause of rectal bleeding and intestinal obstruction in a child with peripheral vascular malformations.

Abdulhameed Aziz; Timothy D. Kane; Manuel P. Meza; Kevin G. Vaughan; David J. Hackam

Vascular malformations of the small bowel are rare yet important causes of abdominal pain and rectal bleeding in children. This report describes a 6-year-old girl with a known history of musculoskeletal vascular anomalies who presented with recurrent abdominal pain and rectal bleeding after seemingly minor trauma. A diagnosis of enteric vascular malformation was established, and the patient was treated by a combined laparoscopic and open approach. This case highlights the fact that in the child with known vascular anomalies who presents with sudden gastrointestinal bleeding and intestinal obstruction, the diagnosis of gastrointestinal vascular anomaly should be suspected, and exploratory laparoscopy should be considered. The current management of enteric vascular anomalies is reviewed, and the differences between vascular malformations and hemangiomas are analyzed.


Urology | 2003

Pelvic hydronephrotic kidney masquerading as obstructed bowel

Deirdre A. Conway; Manuel P. Meza; Steven G. Docimo

A 6 year-old boy presented to an outlying hospital with a 4-day history of abdominal discomfort, constipation, and emesis. An initial computed tomography scan of his abdomen was done without intravenous contrast, and the findings were initially believed to represent a small bowel obstruction (Fig. 1A; see next page for figures). He was referred to our institution for additional treatment. The physical examination revealed a blood pressure of 142/103 mm Hg and a firm lower abdominal mass. The serum creatinine was 0.8 mg/dL. Contrast-enhanced computed tomography of the abdomen and pelvis was performed to delineate the patient’s abnormality more clearly. This revealed the absence of an orthotopic left kidney (Fig. 1B) and a large left ectopic kidney (Fig. 2A), with contrast pooling in the collecting system on delayed images (Fig. 2B). Most ectopic kidneys are asymptomatic and discovered incidentally. However, in a retrospective series, Gleason et al.1 reported that one quarter of 77 patients presenting with renal ectopia were initially evaluated for gastrointestinal complaints. When an orthotopic kidney is not identified, a high index of suspicion for ectopia should guide the imaging choices. Although a variety of imaging modalities can appropriately suggest the diagnosis, contrast-enhanced computed tomography can verify the diagnosis if the ectopic kidney exhibits function.

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James M. Lynch

University of Pittsburgh

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Henri R. Ford

Children's Hospital Los Angeles

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Beverly Newman

University of Pittsburgh

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Evan P. Nadler

Children's National Medical Center

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