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Esophageal motor function in congenital esophageal stenosis
Esophageal Motor Function in Congenital Esophageal Stenosis By Hisayoshi Kawahara, Takaharu Oue, Hiroomi Okuyama, Akio Kubota, and Akira Okada Osaka, Japan
Background/Purpose: Congenital esophageal stenosis (CES) is a rare condition that is associated with various foregut symptoms. The aim of the current study was to investigate esophageal motor function in pediatric patients with isolated CES. Methods: Four boys with CES (age, 3 weeks to 4 years old) were studied before treatment. The initial symptoms were dysphagia or stridor. The CES was caused by fibromuscular stenosis (FMS) in 2, tracheobronchial remnants (TBR) in 1, and membranous diaphragm (MD) in 1. An esophagram, endoscopy, 24-hour esophageal pH monitoring, and manometry were conducted. Results: The esophagram showed the stasis of contrast medium proximally to the distal esophageal narrowing in FMS/ TBR patients. Endoscopic esophagitis was not found in any
C
ONGENITAL ESOPHAGEAL stenosis (CES) is a rare condition that is defined as an intrinsic stenosis of the esophagus caused by a congenital malformation of esophageal wall architecture.1 CES is associated with various foregut symptoms that occasionally remain even after surgical correction. Singaram et al2 reported abnormal innervation in the esophageal body in adult CES patients. Esophageal motor function has been unclarified in isolated CES.3,4 Recent technical innovations have made it possible to examine the details of esophageal motility in small infants.5 The aim of the current study was to investigate esophageal motor function in pediatric patients with CES. MATERIALS AND METHODS
Subjects Four patients with isolated CES were enrolled into the current study. The characteristics of each subject are shown in Table 1. Patients 1 and
From the Department of Pediatric Surgery, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan. Presented at the 36th Annual Meeting of the Pacific Association of Pediatric Surgeons, Sydney, Australia, May 12-16, 2003. Address reprint requests to Hisayoshi Kawahara, MD, Department of Pediatric Surgery, Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Murodo-cho Izumi, Osaka, 594-1101 Japan. © 2003 Elsevier Inc. All rights reserved. 0022-3468/03/3812-0004$30.00/0 doi:10.1016/j.jpedsurg.2003.08.020 1716
patients. Three patients were documented with pathologic esophageal acid exposure by 24-hour esophageal pH monitoring. Manometry showed that esophageal contractions predominantly were synchronous in FMS/TBR patients but were peristaltic in an MD patient. Basal lower esophageal sphincter (LES) pressure was at least 20 mm Hg in all. Swallow-induced LES relaxations were incomplete in FMS/ TBR patients. Conclusions: The presence of gastroesophageal reflux and impaired esophageal motility are common in patients with CES. J Pediatr Surg 38:1716-1719. © 2003 Elsevier Inc. All rights reserved. INDEX WORDS: Congenital esophageal stenosis, manometry, gastroesophageal reflex, lower esophageal sphincter.
2 underwent longitudinal esophageal myotomy, and patient 3 had segmental resection of a narrow area with primary anastomosis after the current study. The CES was caused by fibromuscular stenosis (FMS) in cases 1 and 2, and tracheobronchial remnants (TBR) in case 3, in which the diagnosis was made by microscopy of the surgical specimens. Case 4 was diagnosed as membranous diaphragm (MD) by endoscopy
Study Design Esophagram, endoscopy, 24-hour esophageal pH monitoring, and manometry were conducted in the 4 subjects before treatment. Esophagram. Barium contrast study was conducted in the supine position without any sedation. Barium was given orally to examine its passage in the esophagus as well as the anatomic abnormalities of the esophagus. Endoscopy. Endoscopy was conducted under general anesthesia. Endoscopic esophagitis was diagnosed when there were any of the following mucosal findings: erosion, ulceration, increased friability or granularity, spontaneous bleeding, or leukoplakia. 24-hour esophageal pH monitoring. Esophageal pH monitoring was conducted with the Digitrapper Mark III (Medtronic, MN). The percentage total time of esophageal pH below 4.0 was obtained with 24-hour measurement of pH in the distal esophagus. Esophageal acid exposure was defined as pathologic when the percentage total time of esophageal pH below 4.0 was over 5%. Esophageal manometry. Esophageal manometry was conducted with the system reported previously.5 Multiple channel SILASTIC® (Dow Corning, Midland, MI) assemblies (OD 2.5 mm) with a Dentsleeve sensor (Dentsleeve Pty. Ltd. Adelaide, Australia) were used to measure intraluminal pressure changes in the pharynx, esophageal body, lower esophageal sphincter (LES), and stomach. The pH in the distal esophagus was measured concurrently to know the occurrence of reflux except for case 4. The pressure changes were recorded with a personal computer and were analyzed with specified software (Medtronic, MN). Medication, which could affect gastrointestinal motility, was stopped more than 48 hours before the study. Measurements
Journal of Pediatric Surgery, Vol 38, No 12 (December), 2003: pp 1716-1719
ESOPHAGEAL MOTOR FUNCTION IN CES
1717
Table 1. Characteristics and Results for Individual Subjects
Age at study Associated anomalies Symptoms 24-h pH monitoring (% time pH ⬍ 4.0) Manometry (esophageal body) LES basal tone swallow-induced relaxation mean nadir pressure*
Case 1
Case 2
Case 3
Case 4
4 yr Anorectal anomaly, 21 trisomy Dysphagia, failure to thrive 0.3 Synchronous
3 yr Duodenal atresia, 21 trisomy Dysphagia, failure to thrive 8 Synchronous
3 wk Anorectal anomaly, renal dysplasia Stridor
1y — Dysphagia
13 Synchronous
12 Peristaltic
30 mm Hg Incomplete 13 mm Hg
20 mm Hg Incomplete 10 mm Hg
25 mm Hg Incomplete 16 mm Hg
20 mm Hg Complete
*Mean nadir pressure, mean nadir LES pressure during swallow-induced LES relaxations.
were conducted for 1 hour without sedation. The mean nadir LES pressure during swallow-induced LES relaxations was determined from the nadir pressure during 10 spontaneous swallows, using intragastric pressure as the reference.
RESULTS
Esophagram Stasis of the contrast medium was observed in the esophageal body proximal to the distal esophageal narrowing in cases 1, 2, and 3 (Fig 1). The contrast medium was cleared swiftly in case 4. Endoscopy Intraluminal narrowing was observed in the distal esophagus in cases 1, 2, and 3. A membranous diaphragm with a small hole was observed in case 4. Endoscopic esophagitis was not observed in any case. 24-hour Esophageal pH Monitoring The percentage total time of esophageal pH below 4.0 in each subject is shown in Table 1. Cases 2, 3, and 4 were diagnosed as pathologic esophageal acid exposure.
Esophageal Manometry Esophageal contractions were mostly synchronous in cases 1, 2, and 3. The mean nadir LES pressure during swallow-induced LES relaxations was at least 10 mm Hg in those subjects (Table 1), which meant that swallowinduced LES relaxations were incomplete (Fig 2). Esophageal contractions were peristaltic, and swallowinduced LES relaxations were complete in case 4 (Fig 3). Basal LES pressure was at least 20 mm Hg in all (Table 1). Reflux episodes, detected by a pH drop or common cavity phenomenon,10 occurred predominantly during transient LES relaxations in all, as shown in Figs 2 and 3. DISCUSSION
CES is an extremely rare condition that often is compared with peptic esophageal stricture and achalasia.6 Esophageal motor function has been well investigated in the latter 2 conditions, but it remains unclarifed in CES. To our knowledge, manometric data in CES children were reported only by the Pittsburgh group, which showed a segmental aperistaltic zone at the level of the
Fig 1. Esophagram in each subject. The narrowing (arrow) was located in the distal esophagus in cases 1 (A), 2 (B), and 3 (C), and in the middle esophagus in case 4 (D).
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KAWAHARA ET AL
Fig 2. A sample manometric tracing in case 1. From the top, pressure changes in the pharynx, esophageal body, LES, and stomach are shown. The bottom channel shows pH in the distal esophagus. Swallow-induced esophageal contractions were mostly synchronous. GER, shown as a pH drop in the bottom channel, occurred during a transient LES relaxation. The LES relaxed completely during a transient LES relaxation, whereas the LES relaxed incompletely when triggered by swallowing.
Fig 3. A sample manometric tracing in case 4. Peristaltic esophageal contraction and complete swallow-induced LES relaxation were induced by swallowing. Common cavity phenomenon in the esophageal channels, which indicated the occurrence of GER, was observed during a transient LES relaxation.
ESOPHAGEAL MOTOR FUNCTION IN CES
1719
stenosis and local decreased pliability.3,4 In the current study, esophageal contractions were predominantly synchronous in patients with FMS/TBR but were peristaltic in a patient with MD. The diverse patterns of esophageal contractions shown in the current study might be related to the architectural difference of the lesions. The structural abnormalities, which might affect esophageal motility, are in the submucosal layer or muscle layer in patients with FMS/TBR but are only in the mucosal layer in those with MD. Another possible mechanism is the difference in esophageal innervation between FMS/TBR and MD. Singaram et al2 have recently reported a lack of nitric oxide (NO) inhibitory innervation in the esophageal body in adult CES patients. Yamato et al7 showed that NO is involved in the latency period of esophageal contractions in the opossum. These data suggest that synchronous contractions seen in patients with FMS/ TBR could be related to abnormal innervation of NO in those conditions. Bluestone et al3 described that the superior and inferior sphincters responded normally to swallowing. In the current study, swallow-induced LES relaxations were incomplete in patients with the lesion in the distal esophagus (cases 1, 2, and 3). We used a Dentsleeve sensor to monitor dynamic changes of LES pressure, which is considered to be more reliable than the sidehole those investigators used. The structural abnormalities close to the LES may have a significant impact on the LES function.6 The presence of gastroesophageal reflux (GER) in
patients with CES is not a prevalent consideration, but it could be associated with CES, making appropriate management even more difficult. Diab et al6 reported on an 8-month-old boy who showed massive GER after successful esophageal dilatation. Nihoul-Fekete et al1 reported on a 9-month-old boy who had severe GER after excision of a diaphragm located in the middle esophagus. Yeung et al8 reported on 8 CES children with esophageal atresia, of whom, 5 had radiologic evidence of GER. We previously reported that 10 of 11 CES patients with esophageal atresia had associated pathologic GER.9 In the current study, 3 of 4 patients with isolated CES were documented with pathologic esophageal acid exposure. Case 1 was not associated with pathologic esophageal acid exposure possibly because of severe stenosis in the distal esophagus, whereas case 2 with milder stenosis had more esophageal acid exposure. Reflux episodes occurred predominantly during transient LES relaxation in patients with CES, which also is the main mechanism of GER in children without any esophageal anomaly.10 It is notable that the LES relaxed completely during transient LES relaxation in patients with FMS/TBR, whereas LES relaxation was incomplete when triggered by swallowing as shown in Fig 2. The current study showed the presence of GER and impaired esophageal motility in CES. Further investigation in esophageal motor function may provide a better understanding of the pathophysiology, diagnosis, and treatment of CES.
REFERENCES 1. Nihoul-Fekete C, Backer A De, Lortat-Jacob S, et al: Congenital esophageal stenosis. A review of 20 cases. Pediatr Surg Int 2:86-92, 1987 2. Singaram C, Sweet MA, Gaumnitz EA, et al: Peptidergic and nitrinergic denervation in congenital esophageal stenosis. Gastroenterology 109:275-281, 1995 3. Bluestone CD, Kerry R, Sieber WK, et al: Congenital esophageal stenosis. Laryngoscope 79:1095-1101, 1969 4. Dominguez R, Zarabi M, Oh KS, et al: Congenital oesophageal stenosis. Clin Radiol 36:263-266, 1985 5. Kawahara H, Imura K, Yagi M, et al: Mechanisms underlying the antireflux effect of Nissen fundoplication in children. J Pediatr Surg 33:1618-1622, 1998
6. Diab N, Daher P, Ghorayeb Z, et al: Congenital esophageal stenosis. Eur J Pediatr Surg 9:177-181, 1990 7. Yamato S, Spechler SJ, Goyal RK: Role of nitric oxide in esophageal peristalsis in the opossum. Gastroenterology 103:197-204, 1992 8. Yeung CK, Spitz L, Brereton RJ, et al: Congenital esophageal stenosis due to tracheobronchial remnant: A rare but important association with esophageal atresia. J Pediatr Surg 27:852-855, 1992 9. Kawahara H, Imura K, Yagi M, et al: Clinical characteristics of congenital esophageal stenosis distal to associated esophageal atresia. Surgery 129:29-38, 2001 10. Kawahara H, Dent J, Davidson G: Mechanisms responsible for gastroesophageal reflux in children. Gastroenterology 113:399-408, 1997
Background/Purpose: Congenital esophageal stenosis (CES) is a rare condition that is associated with various foregut symptoms. The aim of the current study was to investigate esophageal motor function in pediatric patients with isolated CES. Methods: Four boys with CES (age, 3 weeks to 4 years old) were studied before treatment. The initial symptoms were dysphagia or stridor. The CES was caused by fibromuscular stenosis (FMS) in 2, tracheobronchial remnants (TBR) in 1, and membranous diaphragm (MD) in 1. An esophagram, endoscopy, 24-hour esophageal pH monitoring, and manometry were conducted. Results: The esophagram showed the stasis of contrast medium proximally to the distal esophageal narrowing in FMS/ TBR patients. Endoscopic esophagitis was not found in any
C
ONGENITAL ESOPHAGEAL stenosis (CES) is a rare condition that is defined as an intrinsic stenosis of the esophagus caused by a congenital malformation of esophageal wall architecture.1 CES is associated with various foregut symptoms that occasionally remain even after surgical correction. Singaram et al2 reported abnormal innervation in the esophageal body in adult CES patients. Esophageal motor function has been unclarified in isolated CES.3,4 Recent technical innovations have made it possible to examine the details of esophageal motility in small infants.5 The aim of the current study was to investigate esophageal motor function in pediatric patients with CES. MATERIALS AND METHODS
Subjects Four patients with isolated CES were enrolled into the current study. The characteristics of each subject are shown in Table 1. Patients 1 and
From the Department of Pediatric Surgery, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan. Presented at the 36th Annual Meeting of the Pacific Association of Pediatric Surgeons, Sydney, Australia, May 12-16, 2003. Address reprint requests to Hisayoshi Kawahara, MD, Department of Pediatric Surgery, Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Murodo-cho Izumi, Osaka, 594-1101 Japan. © 2003 Elsevier Inc. All rights reserved. 0022-3468/03/3812-0004$30.00/0 doi:10.1016/j.jpedsurg.2003.08.020 1716
patients. Three patients were documented with pathologic esophageal acid exposure by 24-hour esophageal pH monitoring. Manometry showed that esophageal contractions predominantly were synchronous in FMS/TBR patients but were peristaltic in an MD patient. Basal lower esophageal sphincter (LES) pressure was at least 20 mm Hg in all. Swallow-induced LES relaxations were incomplete in FMS/ TBR patients. Conclusions: The presence of gastroesophageal reflux and impaired esophageal motility are common in patients with CES. J Pediatr Surg 38:1716-1719. © 2003 Elsevier Inc. All rights reserved. INDEX WORDS: Congenital esophageal stenosis, manometry, gastroesophageal reflex, lower esophageal sphincter.
2 underwent longitudinal esophageal myotomy, and patient 3 had segmental resection of a narrow area with primary anastomosis after the current study. The CES was caused by fibromuscular stenosis (FMS) in cases 1 and 2, and tracheobronchial remnants (TBR) in case 3, in which the diagnosis was made by microscopy of the surgical specimens. Case 4 was diagnosed as membranous diaphragm (MD) by endoscopy
Study Design Esophagram, endoscopy, 24-hour esophageal pH monitoring, and manometry were conducted in the 4 subjects before treatment. Esophagram. Barium contrast study was conducted in the supine position without any sedation. Barium was given orally to examine its passage in the esophagus as well as the anatomic abnormalities of the esophagus. Endoscopy. Endoscopy was conducted under general anesthesia. Endoscopic esophagitis was diagnosed when there were any of the following mucosal findings: erosion, ulceration, increased friability or granularity, spontaneous bleeding, or leukoplakia. 24-hour esophageal pH monitoring. Esophageal pH monitoring was conducted with the Digitrapper Mark III (Medtronic, MN). The percentage total time of esophageal pH below 4.0 was obtained with 24-hour measurement of pH in the distal esophagus. Esophageal acid exposure was defined as pathologic when the percentage total time of esophageal pH below 4.0 was over 5%. Esophageal manometry. Esophageal manometry was conducted with the system reported previously.5 Multiple channel SILASTIC® (Dow Corning, Midland, MI) assemblies (OD 2.5 mm) with a Dentsleeve sensor (Dentsleeve Pty. Ltd. Adelaide, Australia) were used to measure intraluminal pressure changes in the pharynx, esophageal body, lower esophageal sphincter (LES), and stomach. The pH in the distal esophagus was measured concurrently to know the occurrence of reflux except for case 4. The pressure changes were recorded with a personal computer and were analyzed with specified software (Medtronic, MN). Medication, which could affect gastrointestinal motility, was stopped more than 48 hours before the study. Measurements
Journal of Pediatric Surgery, Vol 38, No 12 (December), 2003: pp 1716-1719
ESOPHAGEAL MOTOR FUNCTION IN CES
1717
Table 1. Characteristics and Results for Individual Subjects
Age at study Associated anomalies Symptoms 24-h pH monitoring (% time pH ⬍ 4.0) Manometry (esophageal body) LES basal tone swallow-induced relaxation mean nadir pressure*
Case 1
Case 2
Case 3
Case 4
4 yr Anorectal anomaly, 21 trisomy Dysphagia, failure to thrive 0.3 Synchronous
3 yr Duodenal atresia, 21 trisomy Dysphagia, failure to thrive 8 Synchronous
3 wk Anorectal anomaly, renal dysplasia Stridor
1y — Dysphagia
13 Synchronous
12 Peristaltic
30 mm Hg Incomplete 13 mm Hg
20 mm Hg Incomplete 10 mm Hg
25 mm Hg Incomplete 16 mm Hg
20 mm Hg Complete
*Mean nadir pressure, mean nadir LES pressure during swallow-induced LES relaxations.
were conducted for 1 hour without sedation. The mean nadir LES pressure during swallow-induced LES relaxations was determined from the nadir pressure during 10 spontaneous swallows, using intragastric pressure as the reference.
RESULTS
Esophagram Stasis of the contrast medium was observed in the esophageal body proximal to the distal esophageal narrowing in cases 1, 2, and 3 (Fig 1). The contrast medium was cleared swiftly in case 4. Endoscopy Intraluminal narrowing was observed in the distal esophagus in cases 1, 2, and 3. A membranous diaphragm with a small hole was observed in case 4. Endoscopic esophagitis was not observed in any case. 24-hour Esophageal pH Monitoring The percentage total time of esophageal pH below 4.0 in each subject is shown in Table 1. Cases 2, 3, and 4 were diagnosed as pathologic esophageal acid exposure.
Esophageal Manometry Esophageal contractions were mostly synchronous in cases 1, 2, and 3. The mean nadir LES pressure during swallow-induced LES relaxations was at least 10 mm Hg in those subjects (Table 1), which meant that swallowinduced LES relaxations were incomplete (Fig 2). Esophageal contractions were peristaltic, and swallowinduced LES relaxations were complete in case 4 (Fig 3). Basal LES pressure was at least 20 mm Hg in all (Table 1). Reflux episodes, detected by a pH drop or common cavity phenomenon,10 occurred predominantly during transient LES relaxations in all, as shown in Figs 2 and 3. DISCUSSION
CES is an extremely rare condition that often is compared with peptic esophageal stricture and achalasia.6 Esophageal motor function has been well investigated in the latter 2 conditions, but it remains unclarifed in CES. To our knowledge, manometric data in CES children were reported only by the Pittsburgh group, which showed a segmental aperistaltic zone at the level of the
Fig 1. Esophagram in each subject. The narrowing (arrow) was located in the distal esophagus in cases 1 (A), 2 (B), and 3 (C), and in the middle esophagus in case 4 (D).
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KAWAHARA ET AL
Fig 2. A sample manometric tracing in case 1. From the top, pressure changes in the pharynx, esophageal body, LES, and stomach are shown. The bottom channel shows pH in the distal esophagus. Swallow-induced esophageal contractions were mostly synchronous. GER, shown as a pH drop in the bottom channel, occurred during a transient LES relaxation. The LES relaxed completely during a transient LES relaxation, whereas the LES relaxed incompletely when triggered by swallowing.
Fig 3. A sample manometric tracing in case 4. Peristaltic esophageal contraction and complete swallow-induced LES relaxation were induced by swallowing. Common cavity phenomenon in the esophageal channels, which indicated the occurrence of GER, was observed during a transient LES relaxation.
ESOPHAGEAL MOTOR FUNCTION IN CES
1719
stenosis and local decreased pliability.3,4 In the current study, esophageal contractions were predominantly synchronous in patients with FMS/TBR but were peristaltic in a patient with MD. The diverse patterns of esophageal contractions shown in the current study might be related to the architectural difference of the lesions. The structural abnormalities, which might affect esophageal motility, are in the submucosal layer or muscle layer in patients with FMS/TBR but are only in the mucosal layer in those with MD. Another possible mechanism is the difference in esophageal innervation between FMS/TBR and MD. Singaram et al2 have recently reported a lack of nitric oxide (NO) inhibitory innervation in the esophageal body in adult CES patients. Yamato et al7 showed that NO is involved in the latency period of esophageal contractions in the opossum. These data suggest that synchronous contractions seen in patients with FMS/ TBR could be related to abnormal innervation of NO in those conditions. Bluestone et al3 described that the superior and inferior sphincters responded normally to swallowing. In the current study, swallow-induced LES relaxations were incomplete in patients with the lesion in the distal esophagus (cases 1, 2, and 3). We used a Dentsleeve sensor to monitor dynamic changes of LES pressure, which is considered to be more reliable than the sidehole those investigators used. The structural abnormalities close to the LES may have a significant impact on the LES function.6 The presence of gastroesophageal reflux (GER) in
patients with CES is not a prevalent consideration, but it could be associated with CES, making appropriate management even more difficult. Diab et al6 reported on an 8-month-old boy who showed massive GER after successful esophageal dilatation. Nihoul-Fekete et al1 reported on a 9-month-old boy who had severe GER after excision of a diaphragm located in the middle esophagus. Yeung et al8 reported on 8 CES children with esophageal atresia, of whom, 5 had radiologic evidence of GER. We previously reported that 10 of 11 CES patients with esophageal atresia had associated pathologic GER.9 In the current study, 3 of 4 patients with isolated CES were documented with pathologic esophageal acid exposure. Case 1 was not associated with pathologic esophageal acid exposure possibly because of severe stenosis in the distal esophagus, whereas case 2 with milder stenosis had more esophageal acid exposure. Reflux episodes occurred predominantly during transient LES relaxation in patients with CES, which also is the main mechanism of GER in children without any esophageal anomaly.10 It is notable that the LES relaxed completely during transient LES relaxation in patients with FMS/TBR, whereas LES relaxation was incomplete when triggered by swallowing as shown in Fig 2. The current study showed the presence of GER and impaired esophageal motility in CES. Further investigation in esophageal motor function may provide a better understanding of the pathophysiology, diagnosis, and treatment of CES.
REFERENCES 1. Nihoul-Fekete C, Backer A De, Lortat-Jacob S, et al: Congenital esophageal stenosis. A review of 20 cases. Pediatr Surg Int 2:86-92, 1987 2. Singaram C, Sweet MA, Gaumnitz EA, et al: Peptidergic and nitrinergic denervation in congenital esophageal stenosis. Gastroenterology 109:275-281, 1995 3. Bluestone CD, Kerry R, Sieber WK, et al: Congenital esophageal stenosis. Laryngoscope 79:1095-1101, 1969 4. Dominguez R, Zarabi M, Oh KS, et al: Congenital oesophageal stenosis. Clin Radiol 36:263-266, 1985 5. Kawahara H, Imura K, Yagi M, et al: Mechanisms underlying the antireflux effect of Nissen fundoplication in children. J Pediatr Surg 33:1618-1622, 1998
6. Diab N, Daher P, Ghorayeb Z, et al: Congenital esophageal stenosis. Eur J Pediatr Surg 9:177-181, 1990 7. Yamato S, Spechler SJ, Goyal RK: Role of nitric oxide in esophageal peristalsis in the opossum. Gastroenterology 103:197-204, 1992 8. Yeung CK, Spitz L, Brereton RJ, et al: Congenital esophageal stenosis due to tracheobronchial remnant: A rare but important association with esophageal atresia. J Pediatr Surg 27:852-855, 1992 9. Kawahara H, Imura K, Yagi M, et al: Clinical characteristics of congenital esophageal stenosis distal to associated esophageal atresia. Surgery 129:29-38, 2001 10. Kawahara H, Dent J, Davidson G: Mechanisms responsible for gastroesophageal reflux in children. Gastroenterology 113:399-408, 1997