Dysgerminoma

The article "Ovarian masses in the pediatric patient" is the basis for this AORN Journal independent study. The behavioral objectives and examination for this program were prepared by Helen Starbuck Pashley, RN, MA, CNOR, with consultation from Trish O'Neill, RN, MS, professional education specialist, Center for Perioperative Education.

A minimum score of 70% on the multiple-choice examination is necessary to earn one contact hour for this independent study. Participants receive feedback on incorrect answers. Each applicant who successfully completes this study will receive a certificate of completion. The deadline for submitting this study is March 31, 1999.

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BEHAVIORAL OBJECTIVES

After reading and studying the article on ovarian masses in the pediatric patient, the nurse will be able to

(1) discuss the incidence of ovarian tumors in the pediatric population,

(2) describe the types of ovarian tumors common to the pediatric patient,

(3) identify the signs and symptoms of pediatric ovarian tumors, and

(4) discuss the treatment of pediatric ovarian masses.

Pediatric ovarian masses are rare. The estimated incidence of all childhood ovarian lesions is 2.6 cases per 100,000 girls per year.(1) In children less than 15 years of age, malignant ovarian tumors comprise roughly 1% of all cancers.(2) Although experience at pediatric institutions varies, on average, 16% to 55% of pediatric ovarian lesions are malignant.(3) Estimating the risk of malignancy by age may also vary between institutions. Some authors report a higher risk for girls less than nine years of age.(4) Statistics from the Children's Hospital of Philadelphia show that children over nine years of age appear to be at greater risk.(5)

Non-neoplastic or purely cystic lesions represent one third of pediatric ovarian masses and are benign.(6) The predominant nonneoplastic lesion is a functional or follicular cyst that most frequently occurs in the postmenarchal adolescent, although cysts may be present in the neonate secondary to maternal human chorionic gonadotropin ([Beta]HCG) stimulation of the fetal ovaries. While childhood ovarian masses may present in utero through adolescence, most affected children are diagnosed between 10 and 14 years of age.

Pediatric ovarian masses display a broad range of pathology with varying clinical behavior. Despite the overall rarity of ovarian masses in the pediatric population, the relatively high potential for malignancy necessitates prompt evaluation and treatment. Current goals of therapy should be aimed at cure and preservation of fertility.

PRESENTATION

Pediatric ovarian masses occur as a variety of pathologic subtypes, each presenting with a relatively similar pattern of symptoms and signs. The most frequently encountered complaint of girls harboring an ovarian mass is abdominal pain.(7) The pain is typically mid-abdominal, because the ovaries, attached to an elongated pedicle, do not descend into the pelvis until puberty. As a result, ovarian masses may mimic other intraabdominal, processes, specifically appendicitis or other tumors.

Pain associated with these masses may be either acute, subacute, or chronic. When torsion of the ovary on its vascular pedicle with infarction occurs, severe and unremitting pain results. Physical findings are often consistent with what is known as an "acute abdomen" (ie, pain, tenderness, guarding, nausea, vomiting) and may be easily confused with acute appendicitis. Interestingly, the majority of pediatric ovarian masses may present on the right side, although without good explanation.(8) Other children may have a more insidious pattern of less severe abdominal discomfort that fluctuates and persists over weeks to months and is often ascribed to such processes as gastroenteritis or irritable bowel. Common constitutional symptoms may include nausea, emesis, fever, and anorexia. Parents may find an abdominal mass, fullness, or distension when bathing a young girl or during play. Prepubertal girls may present with precocious puberty if their tumors are hormonally active, and display premature secondary sex characteristics (eg, enlargement of breast buds, areolar discoloration, pubic hair, vaginal bleeding, vulvar hypertrophy).(9) Other less common symptoms include urinary frequency, dysuria, and intestinal obstruction when these structures are involved.

DIAGNOSTICS EVALUATION

As with any medical dilemma, an accurate diagnosis begins with a thorough history and physical examination, addressing those signs and symptoms noted above. A complete review of systems also is important to elicit the possibility of disseminated disease. On examination, a suprapubic mass, often extending above the umbilicus, is frequently palpable (Figure 1). Torsion of the tumor and ovary may lead to necrosis with localized peritoneal irritation and tenderness on abdominal palpation (Figure 2).

[Figure 1-2 ILLUSTRATION OMITTED]

The ovary is not the most common origin of symptomatic abdominal masses in the female pediatric patient, therefore, further data are helpful in establishing the correct diagnosis. Initial diagnostic tools should include abdominal radiographs to evaluate the bowel gas pattern and to exclude other abdominal processes. These films may reveal findings suggestive of ovarian pathology, including intraabdominal calcifications and teeth consistent with a teratoma or displacement of bowel gas representing a nonspecific mass effect.(10) Transabdominal ultrasonography of the ovaries is the best tool for establishing the origin and volume of a given mass and to distinguish cystic from solid tumors. Predominantly solid tumors with a thickened capsule and irregular contour are highly suspicious for malignancy.(11) Although computerized tomography scans and magnetic resonance imaging have been proposed as initial diagnostic tools, these technologies rarely add information not ascertained with sonographic techniques and are usually reserved for staging purposes.

A battery of studies including liver function tests and a complete blood count are helpful in assessing the patient's overall metabolic state and the integrity of her bone marrow function. Tumor markers, specifically [Beta]HCG, alpha fetoprotein ([Alpha]FP), cancer antigen (CA-125), and carcinoembryonic antigen (CEA), should be obtained before beginning definitive care to follow the patient's response to therapy and to monitor for recurrence of disease. Metastatic evaluation should include routine chest radiographs and should be carried out according to specific symptoms.

EMBRYOLOGY

In order to understand the broad range of ovarian pathology and the clinical significance of each tumor, one must review the embryological origins of the various histologic subtypes.(12) The developed ovary consists of three functioning cell types, the oocyte or egg, the follicular cells, and the supporting stromal cells. Each of these cell types can develop into a distinct class of ovarian tumor.

Oocytes are derivatives of the primordial germ cells that can result in germ cell tumors and represent the most common benign or malignant pediatric ovarian masses. Follicular cells are of epithelial origin and are important in regulating estrogen production and maturation of the follicle. These cells give rise to epithelial tumors, which are common adult masses but infrequent childhood lesions. The stromal granulosa and theca cells are of mesenchymal origin. They surround the follicular cells, support their development, and are the origin of stromal mesenchymal tumors, the least frequent variety of both pediatric and adult ovarian lesions. Any of these cell lineages may acquire neoplastic properties, resulting in the development of a wide array of histologic subtypes with variable clinical implications.

PATHOLOGY

Ovarian masses in childhood have numerous histologic subtypes as a result of their three cell type origins.(13) Although the pediatric spectrum of pathology is similar to that encountered in the adult population, the relative frequency and clinical behavior of each tumor differ between children and adults. Germ cell tumors comprise over two thirds of pediatric ovarian masses, epithelial tumors 17%, stromal tumors 13%, and the remaining 3% are an "other" category that includes such processes as lymphomas.(14) Clinical outcome is strongly influenced by tumor subtype, therefore, an accurate histologic diagnosis is imperative. It is common for a young girl with an ovarian lesion to harbor a benign, mature, cystic teratoma of germ cell derivation.(15) A malignant ovarian mass in a young girl is most likely to be a germ cell tumor, commonly a dysgerminoma.(16) In contrast, adult patients often have follicular cysts if benign and epithelial carcinomas if malignant masses are present.

Germ cell tumors. The most common benign and malignant ovarian tumors affecting the pediatric population are of germ cell derivation. A variety of tumor subtypes exist. Benign germ cell tumors are largely represented by mature cystic teratomas, also referred to as dermoids. Malignant germ cell masses include dysgerminomas, immature teratomas, endodermal sinus tumors, embryonal carcinomas, choriocarcinomas, and mixed germ cell tumors. Mixed germ cell tumors are composed of two or more germ cell subtypes.

Purely cystic teratomas typically are 80% benign and rarely (1% to 3%) malignant.(17) These tumors are composed of elements derived from each of the three primordial germ layers, the ectoderm, mesoderm, and endoderm. Mature cystic teratomas often contain skin appendages, neural tissue, cartilage, bone, respiratory epithelium, pancreas, and intestinal epithelia (Figure 3). As a result, ovarian teratomas commonly demonstrate intraabdominal calcifications on x-ray and may be associated with elevated serum levels of [Alpha]FP. Cystic teratomas tend to be bilateral in approximately 12% of pediatric patients's and frequently have a diameter greater than 10 cm. Simple cystectomy with preservation of the remaining ovarian tissue, or oophorectomy in cases of complete replacement of the ovary, suffice as treatment.(19) One should inspect the contralateral ovary because of the incidence of bilateral disease.

[Figure 3 ILLUSTRATION OMITTED]

Roughly 20% of all teratomas are solid, of which 50% are estimated to be malignant.(20) Malignancy is determined by the degree of immature elements within the tumor. Immature teratomas may contain elements of the various primordial germ layers, although the more aggressive tumors typically contain a predominance of immature neuroepithelium. Solid teratomas may present with peritoneal seeding of their neuroglial elements, which are referred to as gliomatosis peritonei. These peritoneal implants, when possessing mature histology, usually regress following resection of the primary tumor.

Immature teratomas spread via the peritoneal fluid and do not demonstrate distant lymphatic or hematogenous metastasis. The deleterious effects of these tumors result from mechanical and metabolic derangements secondary to the malignant ascites. Given the significant risk for malignancy, girls with solid teratomas should have aggressive surgery including unilateral salpingo-oophorectomy, omentectomy, periaortic lymphadenectomy, close inspection of all peritoneal surfaces with biopsy as indicated, and intraoperative ultrasonography of the contralateral ovary. Radical exenteration (ie, total abdominal hysterectomy with bilateral salpingo-oophorectomy) should be avoided. Postoperative chemotherapy should be considered if the pathology reveals malignant elements. A second surgical examination of the area should follow within four months to assess efficacy of therapy. Overall survival is 70% for malignant teratomas.(21)

Dysgerminomas are the most common of the malignant germ cell tumors. These tumors present at an average age of 16 years, can be quite large, with tumor diameters often exceeding 20 cm, and are bilateral in 10% of affected girls.(22) Operative management is similar to that: described for immature teratomas, although total abdominal hysterectomy and bilateral salpingo-oophorectomy may rarely be indicated with more extensive disease. As these tumors are radiosensitive, postoperative radiotherapy may be wan-anted. Overall survival rates approach 80%.(23)

Other less common malignant germ cell tumors include endodermal sinus tumors, embryonal carcinomas, choriocarcinomas, and mixed germ cell tumors. These lesions tend to behave aggressively, necessitating more radical resection. On the whole they respond poorly to adjuvant chemotherapy and thus remain highly lethal.

Epithelial tumors. While tumors of epithelial origin are the most frequent type encountered in the adult population, these are rare in the pediatric patient and are limited to postmenarchal girls. In childhood, more than 50% of these tumors are malignant.(24)

Benign epithelial tumors include papillary and nonpapillary serous cystadenomas and mucinous cystadenomas. These lesions tend to be smooth and well circumscribed. Cystadenomas, are amenable to partial oophorectomy. Bilateral tumors are common.

Malignant epithelial tumors follow similar pathologic nomenclature, with either serous or mucinous cystadenocarcinomas. The serous cystadenocarcinoma occurs with greater frequency and is generally more aggressive. Bilateral disease is present in approximately 50% of patients affected with the serous tumors and less commonly with mucinous tumors.(25)

Stromal tumors, Stromal or mesenchymal tumors are the least frequently encountered of pediatric ovarian masses. Nearly 50% of stromal tumors will be hormonally active resulting in signs of precocious puberty secondary to estrogen production.(26) In childhood, the most common type of this tumor is the granulosa cell tumor. The majority of granulosa cell tumors are benign although often they are hormonally active. The incidence of malignancy is reported at less than one third of cases.(27) Theca cell tumors are rarer though they also may present with precocity. These lesions are invariably benign.

Arrhenoblastomas, or Sertoli-Leydig cell tumors, are rare as well in the pediatric population. Because of overproduction of androgen precursors, these tumors present with virilizing symptoms, typically amenorrhea, masculine body habitus, deepening of voice, clitoral enlargement, hirsutism, and reduction in breast size. Familial associations have been recognized.

Functional cysts. These lesions are benign, unilocular cysts that typically arise in adolescence, although they may occur with a relatively high frequency in female neonates. Cyst development in utero is driven by maternal [Beta]HCG while cysts in older children respond to follicle stimulating hormone. Generally these lesions will resolve spontaneously, although they may torse when enlarged or produce sexual precocity when lined with functional granulosa cells. In both situations resection of the cyst is needed.

Large simple cysts, which are otherwise uncomplicated, may be managed by aspiration, marsupialization, or cystectomy while attempting to salvage functional ovarian tissue. Additionally, premenarchal girls with large cysts should be evaluated for other possible sources of excess hormonal-axis stimulation. A palpable ovarian cyst in a neonate has a risk of torsion with ischemic loss of the ovary, thus prompting consideration of surgical decompression or cystectomy.(28) Most neonatal cysts will regress spontaneously, however, and asymptomatic babies should be carefully observed for two months to track resolution of the cyst.

MANAGEMENT

Despite the wide array of pediatric ovarian masses, surgical techniques have evolved that optimize care and avoid dilemmas. The goals of therapy are to cure the patient and to preserve fertility. A successful outcome is dependent on a multidisciplinary approach, including the perioperative nursing team, the surgeons, anesthesia care personnel, and the oncologists.

PERIOPERATIVE NURSING CARE

Preoperative care of the child with an ovarian mass involves extensive teaching of the patient and family by the perioperative nurse. This education includes a description of diagnostic procedures and why they are indicated, as well as a discussion of the preoperative diagnosis. The patient's age will dictate what materials will be best suited to enhance her understanding and experience. At the Children's Hospital of Philadelphia, the perioperative staff members use dolls, drawings, books, anatomic diagrams, and specific procedure-oriented teaching aids to educate the child and her family members about the surgical experience. An explanation of the surgical procedure and a tour of the operating suite and recovery room is an excellent way to make the child and the family more comfortable in the hospital environment. The patient's and family's specific concerns regarding body image, fertility, malignancy, or other age-appropriate matters should also be addressed perioperatively by the patient care team.

INTRAOPERATIVE NURSING CARE

After reviewing the patient's medical record, laboratory values, and surgical/anesthetic consents, the perioperative nurse meets with the patient and family to assess the patient and to answer any further questions. Because these tumors can occur in children from birth to adolescence, the nurse must assess the patient's developmental and intellectual status and tailor his or her approach to each child's circumstance. For example, while all children will be apprehensive, this apprehension may manifest itself differently in an infant or toddler than it would in a school age child or adolescent. Establishing a trusting relationship between the child and the perioperative nurse helps ease this apprehension for both the child and the family. The perioperative nurse should present clear, easy to understand, age-appropriate explanations regarding the surgical experience to the child while in the family's presence, knowing that fear of the unknown and the overall stress of a surgical experience may interfere with the child's and the parent's abilities to understand.(29)

Common developmental fears that children experience are fear of bodily injury, separation from or loss of parents, fears of the unknown, loss of self-control. Or loss of modesty. Through the use of simple explanations, willingness to answer questions, allowing the parents to accompany the child whenever possible, letting the child wear personal items of clothing or bring transitional security objects to the operating room, and the use of distractions such as storytelling, breathing, or counting, the nurse can help the child to cope successfully with this experience.(30)

When the perioperative nurse has finished his or her preoperative assessment of the patient record and the child and family, he or she escorts the patient to the operating suite. The surgical team positions the patient supine on the OR bed and the perioperative nurse places a safety belt across the patient's thighs, and pads all pressure points. After induction of general anesthesia, the anesthesia care provider places an IV and administers a broad-spectrum antibiotic and intubates the patient endotracheally. The perioperative nurse places a grounding pad on the patient's thigh, and inserts a size-appropriate Foley catheter. The anesthesia care provider also may place a nasogastric tube, and, depending on the surgeon's preference and the patient's age, may place an epidural catheter for intraoperative and postoperative analgesia. The perioperative nurse is also responsible for the disposition of all specimens to the appropriate laboratories.

SURGICAL AND MEDICAL CARE

When the surgeon suspects a benign mass based on preoperative evaluation, simple cystectomy or partial oophorectomy usually will suffice. These procedures may be performed using the traditional open abdominal approach or newer laparoscopic techniques. If, however, the surgeon suspects a malignant mass, the approach must be tailored to each ovarian tumor.(31) An adequate abdominal exploration often requires open abdominal surgery with a generous lower abdominal transverse or midline incision.

Initially, the surgeon determines the extent of the tumor's presence by meticulous inspection of all peritoneal surfaces, including the diaphragm. The surgeon samples peritoneal implants for malignant histology, and resects the involved ovary. Depending on the malignant cell type, he or she may resect the ipsilateral fallopian tube and broad ligament with the ovary (unilateral salpingo-oophorectomy). Fallopian tube remnants should be avoided in order to prevent future cornual or ectopic pregnancy. The surgeon must inspect the contralateral ovary carefully for occult tumor due to the frequency of bilateral disease that may be accomplished with intraoperative ultrasound or the ovary may be bivalved as indicated. If the tumor is malignant or clinical suspicion of malignancy is high, the surgeon performs an omentectomy and periaortic lymph node dissection.

Important goals of pediatric surgical oncology include preservation of hormonal function and future fertility. Therefore, the initial procedure is often limited to oophorectomy, and further surgical strategy is dictated by the final pathology report. Only if the contralateral ovary and uterus involvement is extensive, or if they contain aggressive tumors, are exenterating procedures indicated. Incidental appendectomy should be performed to exclude appendicitis as an etiology of any future abdominal or pelvic complaints in these girls.

For malignant tumors, postoperative combination chemotherapy has proven beneficial, and overall survival rates have increased from 20% to 70% since the early 1970s.(32) Alternating cycles of vinblastine, bleomycin, and cisplatin, and actinomycin D. cyclophosphamide, and adriamycin are frequently administered, as originally developed by the Children's Cancer Group. A second laparotomy is often performed four to six months following completion of the initial round of chemotherapy to assess therapeutic efficacy. Radiation therapy is of limited use in pediatric ovarian malignancies because generally these tumors respond poorly. Radiation therapy is restricted to use with dysgerminomas.

POSTOPERATIVE CARE

The anesthesia care provider generally extubates the patient immediately following surgery and with the perioperative nurse and surgeon, transports the patient to the postanesthesia care unit. The patient's postoperative course is largely dependent on the final diagnosis, and final pathology results are usually available within 48 hours. If the mass is malignant, decisions regarding follow-up care will include chemotherapy, radiation therapy, and further surgery. If the mass is benign, the child generally is discharged in several days and has a follow-up visit within a few weeks after surgery.

Physical assessment (eg, for pain, infection, return to activities of daily living), pain management (ie, patient controlled analgesia for children older than seven years, IV, IM or oral analgesics for younger patients), and discharge planning for the child with a malignant mass are important postoperative nursing goals. The nurse will help the parents make arrangements for follow-up care, outpatient chemotherapy, emotional and educational support, and arrange for any other necessary home care services. The patient and family will require considerable emotional support and education during this time and coordination with social services and home health providers is often needed.

CONCLUSION

Pediatric ovarian masses Present a wide range of challenges to the patient and her family, as well as to the nursing staff members, surgeons, and oncologists. Although these childhood tumors are similar to their adult counterparts, the relative frequency of each type of tumor and their clinical behavior differ. The diagnosis of an ovarian mass should be considered in any young girl presenting with abdominal pain, fullness or distension, anorexia, constitutional symptoms, or pubertal precocity. While these symptoms are nonspecific and more commonly due to other causes, evaluation of the ovaries should be included in the patient's overall assessment. Fortunately, the majority of pediatric tumors are benign and can be managed in a way that preserves ovarian function.

In children with malignancies, refinement of surgical techniques and advances in chemotherapeutic protocols have resulted in significant improvement of survival rates as well as preservation of fertility. Although the prognosis of pediatric ovarian tumors has improved significantly during the last quarter century, further research to determine the molecular biology and genetic behavior of these interesting tumors is important if significant future progress is to be made. No routine screening test currently exists for these tumors, and further improvements in outcome depend upon a high level of clinical suspicion directed toward any abdominal mass to provide early detection and treatment.

NOTES

(1.) M A Skinner et al, "Ovarian neoplasms in children," Archives of Surgery 128 (August 1993) 849-854.

(2.) R B Raney, Jr, et al, "Malignant ovarian tumors in children and Adolescents," Cancer 59 (March 1987) 14-20.

(3.) J T van Winter, P S Simmons, K C Podratz, "Surgically treated adnexal masses in infancy, childhood, and adolescence," American Journal of Obstetrics & Gynecology 170 (June 1994) 1780-1789; P W Cronen, H S Nagaraj, "Ovarian tumors in children," Southern Medical Journal 81 (April 1988) 464-468; S H Ein, J M Darte, C A Stephens, "Cystic and solid ovarian tumors in children: A 44-year review," Journal of Pediatric Surgery 5 no 2 (1970) 148-156.

(4.) van Winter, Simmons, Podratz, "Surgically treated adnexal masses in infancy, childhood, and adolescence," 1780-1789.

(5.) M F Brown et al, "Ovarian masses in children: A review of 91 cases of malignant and benign masses," Journal of Pediatric Surgery 28 (July 1993) 930-932.

(6.) K W Ashcraft, T M Holder, Pediatric Surgery (Philadelphia: W B Saunders Co, 1993) 898-904.

(7.) Brown et al, "Ovarian masses in children: A review of 91 cases of malignant and benign masses," 930-932.

(8.) Ein, Darte, Stephens, "Cystic and solid ovarian tumors in children: A 44-year review," 148-156.

(9.) B H Harris, E T Boles, Jr. "Rationalsurgery for tumors of the ovarv in children," Journal of Pediatric Surgery 9 (June 1974) 289-293.

(10.) Cronen, Nagaraj, "Ovarian tumors in children," 464-468.

(11.) Ibid.

(12.) K L Moore, The Developing Human: Clinically Oriented Embryology (Philadelphia: W B Saunders Co, 1988) 262-267.

(13.) E E Lack, R H Young, R E Scully, "Pathology of ovarian neoplasms in childhood and adolescence," Pathology Annual 27 no 2 (1992) 281-356.

(14.) Cronen, Nagaraj, "Ovarian tumors in children," 464-468: Ashcraft, Holder, Pediatric Surgery, 898-904.

(15.) Ashcraft, Holder, Pediatric Surgery, 898-904.

(16.) Cronen, Nagaraj, "Ovarian tumors in children," 464-468.

(17.) Lack, Young, Scully, "Pathology of ovarian neoplasms in childhood and adolescence," 281-356: B Bronsther, M W Abrams, "Ovarian tumors in childhood," "Pediatric Annals (October 1975) 565-574.

(18.) Bronsther, Abrams, "Ovarian tumors in childhood" 565-74.

(19.) N Wollner et al, "Malignant ovarian tumors in childhood: Prognosis in relation to initial therapy," Cancer 37 (April 1976) 1953-1964.

(20.) Bronsther, Abrams, "Ovarian tumors in childhood," 565-574.

(21.) Raney et al, "Malignant ovarian tumors In children and adolescents," 14-20; Lack, Young, Scully, "Pathology of ovarian neoplasms in childhood and adolescence," 281-356.

(22.) Ashcraft, Holder, Pediatric Surgery, 898-904.

(23.) Lack, Young, Scully, "Pathology of ovarian ne-oplasms in childhood and adolescence," 281-356.

(24.) Ashcraft, Holder, Pediatric Surgery, 898-904.

(25.) Ibid.

(26.) Ibid; Lack, Young, Scully, "Pathology of ovarian neoplasms in childhood and adolescence," 281-356.

(27.) Bronsther, Abrams, "Ovarian tumors in childhood," 565-74.

(28.) Ashcraft, Holder, Pediatric Surgery, 898-904.

(29.) Association of Operating Room Nurses, Inc, Age-Specific Competencies for the Pediatric Patient: Preschool, School-Age, and Adolescent Patients (Denver Association of Operating Room Nurses, Inc, 1997) 21-42.

(30.) Ibid.

(31.) Harris, Boles, "Rational surgery for tumors of the ovary in children," 289-293.

(32.) Brown et al, "Ovarian masses in children: A review of 91 cases of malignant and benign masses," 930-932.

Harold N. Lovvorn, III, MD, is a postdoctoral research fellow arid general surgery resident at the Children's Hospital of Philadelphia, and an assistant instructor of general surgery at the University of Pennsylyania, Philadelphia.

Lisa Ann Tucci, RN, BSN, is the laparoscopy specially nurse, laser safety officer, and ear, nose, and throat service team member in the OR at the Children's Hospital of Philadelphia.

Perry W. Stafford, MD, is an attending pediatric surgeon and Director of Trauma and Surgical Critical Care at the Children's Hospital of Philadelphia.

COPYRIGHT 1998 Association of Operating Room Nurses, Inc.
COPYRIGHT 2001 Gale Group