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Dive into the research topics where N. A. Myers is active.

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Featured researches published by N. A. Myers.


Journal of Pediatric Surgery | 1988

Branchial remnants: a review of 58 cases.

Osamu Doi; John M. Hutson; N. A. Myers; Penelope A. McKelvie

Most congenital lateral cervical cysts, fistulae, and skin tags are considered to be from the branchial apparatus. This is a 13-year review of 58 patients (with 66 branchial lesions) who were operated on. There were eight simple cysts and six cysts with a fistula; 43 external fistulae with or without an internal opening, and nine skin tags. Eighty-seven percent (39/45) of patients with skin tags and external fistulae were less than 5 years of age at the time of operation. On the other hand, all eight patients with cysts but no fistula were greater than 9 years of age. Eight lesions were considered to be the first branchial remnants, and 44 lesions were suspected to be from the second branchial cleft. One external fistula with an internal communication to the pharynx at the level of thyrohyoid membrane was considered to be a third (or fourth) branchial remnant. The other branchial cyst with thyroid tissue in its wall was suggested to be a fourth branchial remnant. Pathology of the excised lesions showed columnar, squamous, or a mixed epithelium. Lymphoid aggregates were documented in 31 patients. Duration of hospital stay was short, except for four patients with first cleft defects who stayed more than five days. Three of the four recurrent cases were first branchial remnants, including one case with the first operation performed at another hospital. In view of these findings, first branchial remnants must be excised with extra care.


Journal of Pediatric Surgery | 1997

The vagus and recurrent laryngeal nerves in the rodent experimental model of esophageal atresia

Bao Quan Qi; Jamal Merei; Pam Farmer; Suzanne Hasthorpe; N. A. Myers; Spencer W. Beasley; John M. Hutson

BACKGROUND After surgical correction of their esophageal atresia and tracheoesophageal fistula (EA-TEF), many patients exhibit evidence of esophageal dysmotility. Controversy exists as to whether the esophageal motility disorders result from denervation caused by surgery or from an inherent abnormal innervation of the esophagus. METHODS The present study used an Adriamycin-induced EA-TEF fetal rat model to trace the course and branching of both the vagus and recurrent laryngeal nerves. Abnormalities observed in EA-TEF rat fetuses include: (1) fewer branches from both recurrent laryngeal nerves; (2) deviation of the left vagus from its normal course below the aorta, passing behind the fistula to approach and join with the right vagus to form a single nerve trunk on the right side of the esophagus; (3) relatively few branches from the single vagal nerve trunk (composed of fibers of the left and the right vagus) on the surface of the lower esophagus. CONCLUSIONS Fetuses affected by EA-TEF have inherent abnormalities in the course and branching pattern of the vagus nerves as they descend through the thorax, culminating in a deficient extrinsic nerve fiber plexus in the lower esophagus. These observations may account for the esophageal motility disorders seen in patients who have EA-TEF even before surgical intervention.


Journal of Pediatric Surgery | 1989

Chest wall deformity in patients with repaired esophageal atresia.

P. Chetcuti; N. A. Myers; P.D. Phelan; Spencer W. Beasley; D.R.V. Dickens

Chest wall deformities developed after thoracotomy for esophageal atresia, in 77 of 232 patients (33%) who did not have a congenital vertebral anomaly. Anterior chest wall asymmetry was present in 47, scoliosis in 18 and a combination of both in 12 patients. Scoliosis was convex away from the incision in two thirds of those affected. Anterior chest wall deformity was more common in patients greater than 25 years of age, and scoliosis was more common in patients who had had multiple thoracotomies. Breast surgery to minimize inequality was required in three female patients, and spinal surgery in one patient. Twenty-two of 53 patients with a congenital vertebral anomaly developed scoliosis, eight of whom required surgery. The scoliosis was probably the result of the vertebral anomaly in these patients, who are particularly at risk for progressive deformity.


Pediatric Surgery International | 1999

Intrinsic innervation of the oesophagus in fetal rats with oesophageal atresia

Bao Quan Qi; S. Uemura; Pam Farmer; N. A. Myers; John M. Hutson

Although the aetiology of oesophageal dysmotility after repair of oesophageal atresia and tracheo-oesophageal fistula (OA-TOF) remains controversial, oesophageal dysmotility also is present in isolated TOF or OA before surgery, suggesting a congenital cause. Our previous work with a model of OA-TOF in fetal rats demonstrated an abnormality in the course and branching pattern of the vagus nerve. However, little is known about the intramural nervous components of the atretic oesophagus. The intrinsic innervation of the atretic oesophagus was examined by immunohistological staining to see if there is an abnormality that might account for dysmotility. OA-TOF was induced in fetal rats by injecting adriamycin intraperitoneally into pregnant rats. Forty-eight controls, 40 OA-TOF, and 6 treated fetuses without OA-TOF were recovered. Whole-mount preparations of each oesophagus were stained with fluorescent antibodies against neuron-specific enolase (NSE), vasoactive intestinal peptide (VIP), substance P (SP), and calcitonin gene-related peptide (CGRP). Compared with control fetuses, the density of the nerve plexus, ganglia, and number of cell bodies per ganglion immunostained by NSE, VIP, or SP was significantly reduced in OA-TOF fetuses. CGRP-immunoreactive nerve fibres in the oesophageal wall of both control and OA-TOF animals were found to be connected with extrinsic nerve bundles. No plexus-like nerve fibre network was observed. The results of the present study demonstrated significant abnormalities of the intramural nervous components of the oesophagus in OA-TOF fetal rats, involving both the excitatory (SP-labelled) and inhibitory (VIP-labelled) intramural nerves. These abnormalities may underlie the oesophageal dysmotility seen in OA-TOF patients.


Pediatric Surgery International | 1987

Total colonic aganglionosis: 30 years' experience

D. T. Cass; N. A. Myers

Thirty-two patients with total colonic aganglionosis (TCA) were seen in 30 years, representing 10% of the total number with aganglionosis seen during that period (1954–1983). The mortality rate was 45%, but has shown a progressive decrease from 82% in the first decade to 9% in the last. The improvement is specifically related to earlier diagnosis, control of sepsis, and the use of parenteral nutrition in dealing with ileostomy losses, but appears to have been independent of the definitive surgical procedure. Follow-up study indicates some delay in achieving continence without any clear-cut relationship to the operative procedure. The 32 patients have been reviewed with particular emphasis on sex ratio, age at diagnosis, clinical features, and results of treatment.


Journal of Pediatric Surgery | 1999

Apoptosis in tracheoesophageal embryogenesis in rat embryos with or without adriamycin treatment.

Baiyun Zhou; John M. Hutson; Pamela J. Farmer; Suzanne Hasthorpe; N. A. Myers; Madalena Liu

PURPOSE The aim of this study was to determine whether apoptosis participates in separation of the foregut into trachea and esophagus and to evaluate the potential role of apoptosis in the development of esophageal atresia and tracheoesophageal fistula (EA + TEF) induced by Adriamycin. METHODS Timed-pregnant rats were injected daily with either saline or Adriamycin (2 mg/kg) intraperitoneally on days 6 to 9 of gestation. Paraffin sections were prepared from 31 experimental and 31 control embryos at days 12 and 13 of gestation. Condensed nuclei were identified on the paraffin sections using the TUNEL method. Apoptosis was quantified by counting the positively stained cell nuclei in transverse sections of embryos. RESULTS In day 12 control embryos the number of apoptotic nuclei in both lateral ridges of the foregut was high (15.67 +/- 1.38) but relatively low (4.17 +/- 0.80) in Adriamycin-treated embryos (P< .0001). In day 13 Adriamycin-treated embryos, the number of apoptotic nuclei in the region of the upper esophageal pouch was extremely high (23.78.5 +/- 2.20) compared with no detectable apoptotic nuclei in the control embryos. CONCLUSIONS Apoptosis is required for normal tracheoesophageal embryogenesis and may be an important mechanism to be involved in the embryological development of esophageal atresia and tracheoesophageal fistula.


Journal of Pediatric Surgery | 1990

Secondary esophageal surgery following repair of esophageal atresia with distal tracheoesophageal fistula

N. A. Myers; Spencer W. Beasley; Alex W. Auldist

During the period 1948 through 1988, 498 patients with esophageal atresia and distal tracheoesophageal fistula were admitted to the Royal Childrens Hospital, Melbourne. Fifty patients had a second operative procedure on the esophagus, for anastomotic stricture (30), recurrent fistula (15), both (4), and a postmyotomy diverticulum (1). During the same period, nine patients underwent esophageal replacement and 33 patients a Nissen fundoplication. Improvements in the technique of esophageal anastomosis, and in recent years the use of fundoplication to correct gastroesophageal reflux have led to a marked reduction in the need for secondary surgery to the esophagus after repair of esophageal atresia. Esophageal replacement is rarely required in esophageal atresia and distal tracheoesophageal fistula. One-layer end-to-end esophageal anastomosis using interrupted sutures resulted in the lowest rate of recurrent fistula and anastomotic stricture.


Pediatric Surgery International | 1987

Oesophageal atresia without fistula — anastomosis or replacement?

N. A. Myers; S. W. Beasley; A. W. Auldist; Maxwell Kent; V. Wright; P. Chetcuti

At the Royal Childrens Hospital, Melbourne, 553 babies with oesophageal atresia and/or tracheo-eesophageal fistula have been admitted during the past 39 years; 36 (6.5%) of these had oesophageal atresia without a tracheo-oesophageal fistula. Definitive surgery was performed in 27 patients: the primary definitive procedure was oesphageal anastomosis in 15 and oesophageal replacement in 12. Aspects of diagnosis and selection of the most appropriate treatment modality are discussed, with the results of treatment presented. Our current policy is to perform an oesphhageal anastomosis whenever possible, and this has been successful in 7 of the last 11 patients.


Pediatric Surgery International | 1999

The frequency, significance, and management of a right aortic arch in association with esophageal atresia

B. Bowkett; Spencer W. Beasley; N. A. Myers

Abstract An unrecognised right aortic arch (RAA) found at thoracotomy may complicate the repair of oesophageal atresia (OA) and tracheo-oesophageal fistula (TOF). This paper analyses the patient characteristics, peri-operative management, and outcome of 16 infants with a RAA, and proposes management guidelines. Between 1948 and 1996, 709 patients with OA/TOF were admitted to the Royal Childrens Hospital, of whom 13 had a RAA. Three additional cases from two other paediatric surgical units were included. All 16 case records were reviewed retrospectively. The overall incidence of RAA in OA was 1.8%. Neither a chest radiograph in 16, nor antenatal ultrasonography in 7 detected a RAA. Post-natal echocardiography (ECHG) detected a RAA in only 1 of 7 infants examined; that patient underwent repair of the OA through a left (L) thoracotomy. The other 15 infants underwent initial right (R) thoracotomy. Six of these had a complete repair from the R side and 5 had division of the fistula only; 2 of these 5 had initial division of the fistula, and the OA was repaired through a repeat R thoracotomy 4 and 7 weeks later. In the remaining 4 infants where the fistula could not be located at the initial R thoracotomy, complete repair proved possible through the L chest. Three of these infants underwent an immediate L thoracotomy; the 4th had a delayed L thoracotomy 1 week later. There were 6 deaths: these occurred early in the study and were related to severe prematurity, congenital heart disease (CHD), and post-operative respiratory complications. CHD was identified in 11 of 16 infants (71%). Routine pre-operative ECHG is unreliable in determining the laterality of the aortic arch. Should a RAA be encountered during a R thoracotomy for OA, it is often possible to divide the fistula and repair the OA from that side, but where repair looks potentially difficult it is wise to proceed to an immediate L thoracotomy.


Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology | 1997

Timing and embryology of esophageal atresia and tracheo-esophageal fistula.

Jamal Merei; Pam Farmer; Suzanne Hasthorpe; Bao Quan Qi; S. W. Beasley; N. A. Myers; John M. Hutson

The embryology of tracheo‐esophageal anomalies is controversial. The development of an adriamycin‐treated animal model has enabled improved understanding of the embryogenesis of these anomalies. Using this model, we aimed to describe the events leading to esophageal atresia and tracheo‐esophageal fistula.

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John M. Hutson

Royal Children's Hospital

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Alex W. Auldist

Royal Children's Hospital

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Bao Quan Qi

Royal Children's Hospital

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Pam Farmer

Royal Children's Hospital

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S. W. Beasley

Royal Children's Hospital

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Jamal Merei

Royal Children's Hospital

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A. W. Auldist

Royal Children's Hospital

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C. W. Chow

Royal Children's Hospital

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