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Pulmonary sequestration
Pulmonary sequestration Pulmonary sequestration is a congenital anomaly in which an aberrant systemic artery arising from the thoracic or upper abdominal aorta supplies part of the lung, usually the lower lobe. The sequestered lung may be anatomically distinct from the remainder of the lobe (extralobar), or may be included in the substance of the lobe, in which case it mayor may not have bronchial communication with the rest of the bronchial tree. The patients present, often in the first two decades of life, with recurrent and severe bronchopulmonary infections. Associated anomalies are present, especially in the extralobar variety. Nine cases of sequestration are reviewed, stressing significant clinical, radiological, and arteriographic findings. Preoperative demonstration of the anomalous vessel by aortography has contributed significantly to the planning and safety of the surgical procedure, which was generally a lower lobectomy. Eight out of nine patients survived the procedure.
Kamal G. Khalil, M.D., * and James W. Kilman, M.D., Columbus, Ohio
RlmOnary sequestration is a congenital anomaly of the developing lung primordium in which the most constant feature is the presence of anomalous systemic blood supply to the sequestered lung from the thoracic or abdominal aorta, or their major branches. Communications with the tracheobronchial tree are often incomplete or absent. Classically two forms of sequestration have been described: (I) intralobar sequestration, in which the anomalous lung tissue is in structural continuity with the remainder of the lung and pulmonary venous drainage is generally to the pulmonary veins (Fig. 1), and (2) extralobar sequestration, in which the accessory lung tissue generally has a separate and distinct pleural investment. Communication with the esophagus or stomach has been often noted. The anomalous systemic artery often comes from the aorta under the diaphragm and the anomalous venous return is into systemic (J
From the Ohio State University Hospital, Columbus, Ohio. Received for publication March 20, 1975. Address for reprints: Dr. James W. Kilman, Professor of Surgery, Division of Thoracic Surgery, University Hospital, Ohio State University, Columbus, Ohio 43210. *Currently Faculty Associate, Section of Thoracic Surgery,
M. D. Anderson Hospital and Tumor Institute, 6723 Bertner Ave., Houston, Texas 77025.
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veins, often the hemiazygos or portal systern.' In addition, malformations such as the "scimitar syndrome" have been recognized, in which the right lower lobe of the lung receives systemic supply from the aorta at or below the level of the diaphragm and the venous return is into the inferior vena cava below the diaphragm. The venous return from the right upper lobe is often anomalous and will end into the superior vena cava or right atrium (Fig. 1) .9,1" Materials and results
We reviewed cases of pulmonary sequestration admitted to the Columbus Children's Hospital and the University Hospital of the Ohio State University between 1962 and 1974. Nine cases were found, of which seven were intralobar, one was extralobar, and one was a case of the scimitar syndrome. Eight were male and one was female; their ages varied from 3 to 49 years. The salient features of these cases are presented in Table I. Of these cases, five were in the left lower lobe and three in the right lower lobe. The single case of extralobar sequestration was in the right paraesophageal area just above the diaphragm.
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1. Intralobar sequestration
2. Extralobar sequestration
3. Scimitar syndrome
Fig. 2. Posteroanterior view of the chest in case 1 showing an air fluid level in the lower lobe and surrounding infiltrate. To systemic vein
Fig. 1. Schematic presentation of types of pulmonary sequestration.
Recurrent pneumonia was the presenting symptom in six of the nine patients. In the remaining three, abnormalities on the routine chest x-ray prompted further work-up. The predominant radiological finding was a rounded mass lesion in the lower zone, posteriorly , commonly on the left. Transient or recurrent infiltrates in the same area were very common. Five patients had bronchography, which often showed cystic changes and bronchiectasis in the involved area, or else showed failure of filling of the bronchi supplying the sequestered lung, with evidence of displacement and distortion of the remaining segmental bronchi of the lower lobe. Seven patients had aortograms which demonstrated the anomalous artery or arteries arising from the thoracic or upper abdominal aorta. The predominant surgical procedure was
Fig. 3. Lateral roentgenogram of same case as in Fig. 2, showing the posterior basal location of the cyst.
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Table I. Salient features of 9 cases of pulmonary sequestration Symptoms
Case I. M. S. 1962
49
F
2. M. T. 1963
44
M
1965
3
4. C.C. 1966
Radiography
Origin 01 systemic artery
Right paraesophageal area Right lower lobe
Asymptomatic
2.5 em. rounded mass attached to diaphragm
Thoracic aorta
Malaise, cough
Dextrocardia mass lesion right lower zone
Thoracic aorta
M
Left lower lobe
Respiratory distress at birth
Hyperinflation superior segment of LLL and basal atelectasis
Thoracic aorta
28
M
Left lower lobe
Frequent respiratory infections, dyspnea, hemoptysis
"Mass" in posterior basal segment LLL
Thoracic aorta (2 arteries)
5. W. W.1969
47
M
Left lower lobe
"Asthma," coughing, pus intermittently
Acute and chronic inflammatory changes more marked on left
Thoracic aorta
6. D.C. 1970
19
M
Left lower lobe
Asymptomatic
3 em. mass lesion behind heart with lateral infiltrate
Thoracic aorta
7. C.K. 1973
6
M
Left lower lobe
Recurrent suppurative pneumonia LLL
Mass lesion and major infiltrate LLL
Thoracic aorta
8. W. C. 1974
3
M
7
M
Recurrent pneumonia RLL Asymptomatic
Consolidation RLL
9. K. B. 1974
Right lower lobe Right lower lobe
Abdominal aorta (celiac axis) Thoracic aorta and splenic artery
3. G. I.
lower lobectomy, although two patients had basal segmental resection and one patient had re-routing of the anomalous venous return of the right upper lobe to the left atrium with direct suture implantation. Initially, all patients recovered, but one died on postoperative day 16 following a second procedure for repair of pectus excavatum. The large anomalous systemic artery was isolated and divided at an early stage of the procedure in all cases except two, in which preoperative diagnosis was not made. In one of these, the vessel was found and delibrately divided, but in the other the vessel was accidentally entered and prompt control obtained during the thoracotomy. Preopera-
Dextrocardia, hypoplasia (R) lung?
tive knowledge of the origin and level of the systemic artery added significantly to the safety of the surgical procedure.
Case reports We have chosen three cases for presentation here, to illustrate certain aspects in the diagnosis and management. CASE 1. C. K., a 6-year-old white boy, was admitted to Columbus Children's Hospital on Aug. 20, 1972, with a 3 week history of cough, chest pain, and increasing shortness of breath. The physical findings were compatible with left lower lobe pneumonia. Chest roentgenogram showed an air-fluid level in the posterior basal segment with areas of honeycombing in the remainder of the lower lobe (Figs. 2 and 3). Bronchography showed
Volume 70 Number 5 November, 1975
Pulmonary sequestration
Associated anomalies
None
Therapy
Extralobar
Excision;no bronchial or esophageal communication Undetermined Observation only
Dextrocardia, hypoplasia rightlung, diaphrag.matic hernia containing right kidney Intralobar Hypoplasia RUL, ASD, PDA, pectusexcavatum None
Intralobar
Sliding hiatus hernia
Intralobar
None
Intralobar
None
Intralobar
None
Intralobar
lIone
"Scimitar" syndrome
931
Comment
Recovered
Systemic artery accidentally entered; cystic structure adherent to but anatomically distinct from RLL Bronchogram showscystic RUL, overinflated RML, and hypoplastic RLL; RPA markedly hypoplastic
Left basal segmental resection
Died postop. Continued air leak, pectus repaired day 16 day 12,had hypoxic arrest; PDA and ASD spontaneously closed at autopsy Left lower lobectomy Recovered Bronchogram: displacement of posterior basal bronchi and minimal bronchiectasis; lung scan absent, perfusion posterior basal segment LLL Left lower lobectomy Recovered Bronchogram: extensivebronchiectasis basal segments LLL; basal segments would not deflate appreciably at thoracotomy Left basal segmental Recovered Specimen injected, showedseveral resection communications betweensystemic and pulmonary arteries Left lower lobectomy Recovered Bronchography: fillingof superior segmental bronchus, with partial fillingand lateral displacement of basal bronchi; lung scan showed perfusion deficit in posterior basal segment LLL Right lower lobectomy Recovered Bronchography: no fillingof 3 basal bronchi Right lower lobectomy and Recovered Right lower lobe vein drains in re-routing of anomalous inferior vena cava belowdiaphragm; venous return RUL venousdrainage partly to right atrium
displacement of the superior segmental bronchus of the left lower lobe and incomplete filling of the basal bronchi, which were tiny and distorted. Lung scan showed absent perfusion in the posterior and medial parts of the left lower lobe. Selective aortography demonstrated a I cm. abnormal artery arising from the aorta at the level of the tenth dorsal vertebra and supplying the inferior part of the left lower lobe (Fig. 4). Venous drainage of this area was demonstrated to the inferior pulmonary vein and the left atrium (Fig. 5). The diagnosis of intralobar sequestration was thus documented. Surgery was recommended but the family declined to accept. However, following recurrence of severe pneumonia 9 months later, the family accepted. The consolidated and adherent left lower lobe was carefully isolated and in the area of the pul-
monary ligament the abnormal systemic artery, which measured approximately I em. in diameter, was followed to its origin from the descending thoracic aorta (Fig. 6). The artery was divided between suture ligatures and from then on the procedure was completed uneventfully. The postoperative course was smooth. The resected lobe showed areas of chronic pneumonia and abscess formation and several bronchial cysts, the largest measuring 4 by 4 em. in diameter. The superior segment was relatively uninvolved. CASE 2. W. C., a 3-year-old white boy, was first admitted to Columbus Children's Hospital on Dec. 3, 1973, with a 6 week history of fever and cough that responded only partially to antibiotics. Chest x-ray demonstrated a homogeneous density in the posterior basal segment of the right lower lobe. Sputum cultures grew Hemophilus influenzae, alpha streptococcus, and Neisseria species. Direct
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Khalil and Kilman
Fig. 4. Transfemoral selective arteriogram in case 1 demonstrating the large anomalous systemic artery.
Thoraci c and Cardi ovascular Surgery
Fig. 5. Venous phase of angiogram in case 1 showing the venous drainage to the inferior pulmonary vein.
Fig. 6. Operative exposure of anomalous systemic artery isolated in the pulmonary ligament before it enters the sequestration in case 1. smears for acid-fast bacilli and fungus were negative. In spite of continuous treatment with several antibiotics, and pulmonary toilet , no further improvement occurred. Bronchoscopy demonstrated
patency of the right lower lobe bronchus. Bronchography showed a failure of filling of three of the four right basal segments. The child was readm itted 2 months later with another episode of pneumonia ; at this time aortography demon-
Volume 70 Number 5 November. 1975
strated a larger systemic artery ansmg from the abdominal aorta at the level of the celiac axis and supplying the posterior basal segment of the right lower lobe (Fig. 7). On April 6, 1974, right thoracotomy was done and the right lower lobe isolated with considerable difficulty from the diaphragm and chest wall owing to dense adhesions. A 5 mm. systemic artery was encountered in the area of the pulmonary ligament. Following control of this vessel, lobectomy was achieved in a routine fashion. The postoperative recovery was uncomplicated. Pathological examination of the resected lobe showed the posterior basal segment to be underinflated and devoid of anthracotic pigmentation (Fig. 8). There were several cystic spaces in this area, the largest measuring 1 em. in diameter. Injection of the abnormal systemic artery was done and showed that the venous drainage was to the inferior pulmonary vein. CASE 3. K. B., a 7-year-old black boy, was admitted to the Columbus Children's Hospital on Jan. 24, 1973, following a motor-car accident. At that time a chest x-ray demonstrated dextrocardia and abnormal vascularity of the right lower lobe. Several subsequent x-rays demonstrated no change in the lung findings. Cardiac catheterization and aortogram revealed two systemic arteries supplying the right lower lobe---one arising from the aorta, at the level of the tenth thoracic vertebra, and the second from the splenic artery. The right lower lobe had no pulmonary arterial supply (Fig. 9) and its venous drainage was to the infradiaphragmatic inferior vena cava by a single large anomalous vein (scimitar vein) (Fig. 10). The venous drainage of the right upper lobe appeared to be at least partially connected to the right atrium. The diagnosis of the scimitar syndrome was made. The child was readmitted in August of 1974 and underwent right lower lobectomy and rerouting of the partially anomalous venous drainage to the left atrium, by direct suture implantation in the left atrium without cardiopulmonary bypass. Postoperative recovery was uneventful.
Discussion
Exclusive supply of an area of the lung by one or more anomalous systemic arteries has been recognized as early as 1777. 8 , 12 Several terms were applied to this entity, including lower accessory lung, anomalous lung, and pulmonary sequestration.v' The latter term is preferable since it conforms with an embryologic theory of traction on-and separation of-a portion of the developing lung bud by the anomalous systemic vessel. An alternative theory
Pulmonary sequestration
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Fig. 7. Aortogram of case 2 showing the infradiaphragmatic origin of the anomalous artery from the aorta at the level of the celiac axis.
postulates a supernumerary tracheobronchial bud developing from the primitive foregut distal to the normal level. This accessory bud retains its systemic blood supply and mayor may not retain foregut cornmunication. " This theory more adequately explains extralobar sequestration. A third theory, advanced by Smith," postulates that the primary anomaly is deficiency of the pulmonary artery to the basal segments of the lower lobe. This segment would then retain its primitive systemic supply with subsequent cystic degeneration and fibrosis secondary to the high pressure in the systemic circuit. Perhaps several different mechanisms apply to various types of sequestration. In the present series males constituted eight out of the nine cases. Children and adults were represented almost equally. Fifty-five per cent of the sequestrations presented in the posterior basal segment of the left lower lobe, the classical site for sequestration'"; the remaining cases were in the
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Khalil and Kilman
The Journol of Thorocic ond Cordiovoscular Surgery
Fig. 8. Gross photograph of resected lower lobe of case 2 showing the lack of anthracosis and vague demarcation of the sequestered segment. The vessels and bronchus were cannulated.
Fig. 9. Pulmonary angiogram in case 3 showing the absence of pulmonary artery supply to the right lower lobe.
Fig. 10. Selective catheterization and injection in the "scimitar vein" in case 3 showing its connection to the inferior vena cava.
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November, 1975
right lower lobe. This corresponds with the incidence reported in a review of the literature on sequestration in 1970. 3 Sequestration has also been reported in the upper lobe'" and rarely bilaterally.'; The most frequent clinical presentation is pneumonia in one lower lobe, commonly the left, that only partially responds to conventional therapeutic measures including antibiotics, postural drainage, etc. There is often a history of recurrent infections in the same area of the lung for several years. Bronchiectasis or other bronchial abnormality is suspected, but bronchography often fails to show filling of the corresponding area of the lung, with evidence of distortion and displacement of the nearby bronchi. Bronchiectasis secondary to infection is often present in the neighboring area. The commonest finding in the plain chest roentgenograms has been a mass lesion in the posterior basal segment, with or without surrounding infiltrates. Cystic changes and an air-fluid level have also been noted. Atelectasis and shift of the cardiac silhouette were noted in three cases. The diagnosis was made preoperatively in five of the nine cases by aortography and selective injection in the anomalous systemic vessel. In two of the remaining cases the diagnosis was suspected but aortography not done. A useful screening noninvasive test for patients with suspected sequestration is the lung scan. This demonstrates an area of absent perfusion and, when other data are suggestive, would help select patients to be subjected to arteriography. With increasing awareness of this clinical entity, our last four consecutive patients were definitively diagnosed preoperatively by aortography and/or venous angiography. The level of origin of the systemic artery was from the thoracic aorta in seven out of the nine cases (77 per cent), from the abdominal aorta in one case, and from both the thoracic aorta and the splenic artery in the last case. This corresponds with the experience of several other series in the literature.s- 6, 11, 18 Infradiaphragmatic origin of the feeding artery has been more frequent in
extralobar sequestration, and associated diaphragmatic defect was present in 58 per cent of cases in one series." In a few patients, the left lung was hypoplastic as a result of the associated diaphragmatic hernia. In our series associated congenital anomalies were present in two patients and included dextrocardia, hypoplastic right lung, diaphragmatic hernia, hypoplastic right upper lobe, atrial septal defect, patent ductus arteriosus, and pectus excavatum. Other congenital defects reported include tracheoesophageal fistula," gastric fistula," ectopic gut or pancreatic tissue in the malformation, duplication of gastrointestinal tract, and pericardial cysU 8 The possible hemodynamic significance of the vascular anomaly in pulmonary sequestration was investigated by Solit and associates." They measured the resting cardiac output before and 8 months after resection of an intralobar sequestration in the medial basal segment of the right lower lobe. The cardiac index was 4.24 L. per minute per square meter preoperatively, which was definitely elevated despite the fact that the patient was under basal conditions and his oxygen consumption was not elevated. The postoperative cardiac index dropped to 2.89 L. per minute per square meter. These findings suggest a significant left-to-Ieft shunt produced by the systemic arterial blood flowing directly into tributaries of the pulmonary veins. The patient had no clinical or electrocardiographic criteria of left ventricular hypertrophy or strain. Kergin'" noted marked improvement in the exercise tolerance of one of his patients following removal of the sequestered lower lobe and suggested that in this case the shunting of blood could have been of considerable magnitude, but no physiological measurements were made in that case. The volume of the shunt was generally not huge. It is conceivable that as the patients grow older they might have some harmful effect ultimately on left ventricular function. Three of our patients were asymptomatic at ages 7, 19, and 49, respectively. The only rational treatment of sequestration is to surgically resect the involved area
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The Journal of Thoracic and Cardiovascular Surgery
Khalil and Kilman
of the lung to avoid the sequela of persistent or recurrent infection and possible adverse hemodynamic effect of the left-to-left shunt. The safety of the procedure can be markedly augmented by precise preoperative demonstration of the location and level of the anomalous artery, employing retrograde aortography. The anomalous artery may be quite large and is of the elastic type, resembling the histological structure of a pulmonary artery. This, as well as premature and extensive athromatous change at times, will make surgical handling of the vessel quite precarious. It may be necessary to isolate the aorta above and below the origin of the vessel to obtain optimum control. It should be the habit of every thoracic surgeon to palpate the inferior pulmonary ligament prior to any pulmonary resection since anomalous arteries may arise in this structure even without sequestration." Failure to isolate and control the anomalous systemic artery has in the past resulted in disastrous-and at times fatal-hemorrhage from the stump of the vessel that may retract under the diaphragm.' Unexpected hemorrhage was encountered in the earliest case in this series, explored with a preoperative diagnosis of benign tumor of the diaphragm. A large artery was inadvertently entered while dividing dense adhesions to the retrocardiac area. Fortunately the artery, which arose from the lower thoracic aorta, was quickly clamped and suture ligated, and the extralobar sequestration resected. Although, theoretically, segmental resection would be ideal for intralobar sequestration, generally lobectomy is necessary because of the chronic infection destroying the intersegmental plane, and the presence of bronchiectasis and scarring in the remaining part of the lobe. In this series, seven of the nine patients were treated by lobectomy. Extralobar sequestration can usually be removed completely because of the separate pleural investment. The mortality rate in this series is quite low and this is the experience of other series reported in the literature. The single death in the series was that of a 3-year-old boy
with multiple cardiorespiratory congenital anomalies, including intralobar sequestration. Left basal segmentectomy was followed 12 days later by repair of pectus excavatum; a few hours later sudden respiratory difficulty developed that rapidly ended fatally. Autopsy showed complete atelectasis of the remaining parts of the left lung, pleuritis, and pericarditis. REFERENCES
2 3
4 5
6
7
8 9
10 11 12 13
14
Carter, R.: Collective Review. Pulmonary Sequestration, Ann. Thorac. Surg. 7: 68, 1969. De Bakey, M., Arey, J. B., and Brunazzi, R.: Successful Removal of Lower Accessory Lung, J. THoRAc. SURG. 19: 304, 1950. DeParedes, C. G., Pierce, W. S., Johnson, D. G., and Waldhausen, J. A.: Pulmonary Sequestration in Infants and Children: A 20-Year Experience and Review of the Literature, J. Pediatr. Surg. 5: 136, 1970. Fasburg, R. G., Jakubiak, J. V., and Delaney, T. B.: Congenital Partial Absence of the Pericardium, Ann. Thorac. Surg. 5: 171, 1968. Findley, C. W., Jr., and Maier, H. C.: Anomalies of Pulmonary Vessels and Their Significance, With Review of Literature, Surgery 29: 604, 1951. Gerle, R. D., Jaretzki, A., III, Ashley, C. A., and Berne, A. S.: Congenital Broncho-Pulmonary Foregut Malformation, N. Eng\. J. Med. 278: 1413, 1968. Harris, H. H., and Lewis, J.: Anomalies of the Lung With Special Reference to the Dangers of Abnormal Vessels in Lobectomy, J. THoRAe. SURG. 6: 666, 1940. Huber, J. J.: Cited by McCotter. 12 Johnson, J. B., Chun, S. K., Young, R. c., and McCampbell, E. L.: Scimitar Syndrome: Anomalous Venous Drainage of the Right Lung Into the Inferior Vena Cava With Malformation of Pulmonary Structure, J. Natl. Med. Assoc. 64: 297, 1972. Kergin, F. G.: Congenital Cystic Disease of the Lung Associated With Anomalous Arteries, J. THORAC. SURG. 23: 55, 1952. Kilman, 1. W., Battersby, J. S., Hooshang, T., and VelIios, F. : Pulmonary Sequestration, Arch. Surg. 90: 648, 1965. McCotter, R. E.: On the Occurrence of Pulmonary Arteries Arising From the Thoracic Aorta, Anal. Rec. 4: 291, 1910. Nikaidah, H., and Sewenson, 0.: The Ectopic Origin of the Right Main Bronchus From the Esophagus, J. THORAC. CARDIOVASC. SURG. 62: 1, 1971. Pryce, D. M., Sellors, T. H., and Blair, L. G.:
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Intralobar Sequestration of Lung Associated With Abnormal Pulmonary Artery, Br. 1. Surg. 35: 18, 1947. 15 Saegessen, F., and Besson, A.: Extralobar and Intralobar Pulmonary Sequestration of the Upper and Lower Lobes, Chest 63: 69, 1973. 16 Smith, R. A.: Theory of Origin of Intralobar Sequestration, Thorax 11: 10, 1956.
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17 SoIit, R. W., Traimow, W., Wallace, S., and Cohn, H. E.: The Effect of Intralobar Pulmonary Sequestration on Cardiac Output, J. THoRAc. CARDIOVASC. SURG. 49: 844, 1965. 18 Witten, D. M., Clagett, O. T., and Woolner, L. B.: Intralobar Sequestration Involving the Upper Lobes, J. THORAC. CARDIOVASC. SURG. 43: 523, 1962.
Kamal G. Khalil, M.D., * and James W. Kilman, M.D., Columbus, Ohio
RlmOnary sequestration is a congenital anomaly of the developing lung primordium in which the most constant feature is the presence of anomalous systemic blood supply to the sequestered lung from the thoracic or abdominal aorta, or their major branches. Communications with the tracheobronchial tree are often incomplete or absent. Classically two forms of sequestration have been described: (I) intralobar sequestration, in which the anomalous lung tissue is in structural continuity with the remainder of the lung and pulmonary venous drainage is generally to the pulmonary veins (Fig. 1), and (2) extralobar sequestration, in which the accessory lung tissue generally has a separate and distinct pleural investment. Communication with the esophagus or stomach has been often noted. The anomalous systemic artery often comes from the aorta under the diaphragm and the anomalous venous return is into systemic (J
From the Ohio State University Hospital, Columbus, Ohio. Received for publication March 20, 1975. Address for reprints: Dr. James W. Kilman, Professor of Surgery, Division of Thoracic Surgery, University Hospital, Ohio State University, Columbus, Ohio 43210. *Currently Faculty Associate, Section of Thoracic Surgery,
M. D. Anderson Hospital and Tumor Institute, 6723 Bertner Ave., Houston, Texas 77025.
928
veins, often the hemiazygos or portal systern.' In addition, malformations such as the "scimitar syndrome" have been recognized, in which the right lower lobe of the lung receives systemic supply from the aorta at or below the level of the diaphragm and the venous return is into the inferior vena cava below the diaphragm. The venous return from the right upper lobe is often anomalous and will end into the superior vena cava or right atrium (Fig. 1) .9,1" Materials and results
We reviewed cases of pulmonary sequestration admitted to the Columbus Children's Hospital and the University Hospital of the Ohio State University between 1962 and 1974. Nine cases were found, of which seven were intralobar, one was extralobar, and one was a case of the scimitar syndrome. Eight were male and one was female; their ages varied from 3 to 49 years. The salient features of these cases are presented in Table I. Of these cases, five were in the left lower lobe and three in the right lower lobe. The single case of extralobar sequestration was in the right paraesophageal area just above the diaphragm.
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Pulmonary sequestration
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1. Intralobar sequestration
2. Extralobar sequestration
3. Scimitar syndrome
Fig. 2. Posteroanterior view of the chest in case 1 showing an air fluid level in the lower lobe and surrounding infiltrate. To systemic vein
Fig. 1. Schematic presentation of types of pulmonary sequestration.
Recurrent pneumonia was the presenting symptom in six of the nine patients. In the remaining three, abnormalities on the routine chest x-ray prompted further work-up. The predominant radiological finding was a rounded mass lesion in the lower zone, posteriorly , commonly on the left. Transient or recurrent infiltrates in the same area were very common. Five patients had bronchography, which often showed cystic changes and bronchiectasis in the involved area, or else showed failure of filling of the bronchi supplying the sequestered lung, with evidence of displacement and distortion of the remaining segmental bronchi of the lower lobe. Seven patients had aortograms which demonstrated the anomalous artery or arteries arising from the thoracic or upper abdominal aorta. The predominant surgical procedure was
Fig. 3. Lateral roentgenogram of same case as in Fig. 2, showing the posterior basal location of the cyst.
930
The Journol of Thorocic and Cardiovascular Surgery
Khalil and Kilman
Table I. Salient features of 9 cases of pulmonary sequestration Symptoms
Case I. M. S. 1962
49
F
2. M. T. 1963
44
M
1965
3
4. C.C. 1966
Radiography
Origin 01 systemic artery
Right paraesophageal area Right lower lobe
Asymptomatic
2.5 em. rounded mass attached to diaphragm
Thoracic aorta
Malaise, cough
Dextrocardia mass lesion right lower zone
Thoracic aorta
M
Left lower lobe
Respiratory distress at birth
Hyperinflation superior segment of LLL and basal atelectasis
Thoracic aorta
28
M
Left lower lobe
Frequent respiratory infections, dyspnea, hemoptysis
"Mass" in posterior basal segment LLL
Thoracic aorta (2 arteries)
5. W. W.1969
47
M
Left lower lobe
"Asthma," coughing, pus intermittently
Acute and chronic inflammatory changes more marked on left
Thoracic aorta
6. D.C. 1970
19
M
Left lower lobe
Asymptomatic
3 em. mass lesion behind heart with lateral infiltrate
Thoracic aorta
7. C.K. 1973
6
M
Left lower lobe
Recurrent suppurative pneumonia LLL
Mass lesion and major infiltrate LLL
Thoracic aorta
8. W. C. 1974
3
M
7
M
Recurrent pneumonia RLL Asymptomatic
Consolidation RLL
9. K. B. 1974
Right lower lobe Right lower lobe
Abdominal aorta (celiac axis) Thoracic aorta and splenic artery
3. G. I.
lower lobectomy, although two patients had basal segmental resection and one patient had re-routing of the anomalous venous return of the right upper lobe to the left atrium with direct suture implantation. Initially, all patients recovered, but one died on postoperative day 16 following a second procedure for repair of pectus excavatum. The large anomalous systemic artery was isolated and divided at an early stage of the procedure in all cases except two, in which preoperative diagnosis was not made. In one of these, the vessel was found and delibrately divided, but in the other the vessel was accidentally entered and prompt control obtained during the thoracotomy. Preopera-
Dextrocardia, hypoplasia (R) lung?
tive knowledge of the origin and level of the systemic artery added significantly to the safety of the surgical procedure.
Case reports We have chosen three cases for presentation here, to illustrate certain aspects in the diagnosis and management. CASE 1. C. K., a 6-year-old white boy, was admitted to Columbus Children's Hospital on Aug. 20, 1972, with a 3 week history of cough, chest pain, and increasing shortness of breath. The physical findings were compatible with left lower lobe pneumonia. Chest roentgenogram showed an air-fluid level in the posterior basal segment with areas of honeycombing in the remainder of the lower lobe (Figs. 2 and 3). Bronchography showed
Volume 70 Number 5 November, 1975
Pulmonary sequestration
Associated anomalies
None
Therapy
Extralobar
Excision;no bronchial or esophageal communication Undetermined Observation only
Dextrocardia, hypoplasia rightlung, diaphrag.matic hernia containing right kidney Intralobar Hypoplasia RUL, ASD, PDA, pectusexcavatum None
Intralobar
Sliding hiatus hernia
Intralobar
None
Intralobar
None
Intralobar
None
Intralobar
lIone
"Scimitar" syndrome
931
Comment
Recovered
Systemic artery accidentally entered; cystic structure adherent to but anatomically distinct from RLL Bronchogram showscystic RUL, overinflated RML, and hypoplastic RLL; RPA markedly hypoplastic
Left basal segmental resection
Died postop. Continued air leak, pectus repaired day 16 day 12,had hypoxic arrest; PDA and ASD spontaneously closed at autopsy Left lower lobectomy Recovered Bronchogram: displacement of posterior basal bronchi and minimal bronchiectasis; lung scan absent, perfusion posterior basal segment LLL Left lower lobectomy Recovered Bronchogram: extensivebronchiectasis basal segments LLL; basal segments would not deflate appreciably at thoracotomy Left basal segmental Recovered Specimen injected, showedseveral resection communications betweensystemic and pulmonary arteries Left lower lobectomy Recovered Bronchography: fillingof superior segmental bronchus, with partial fillingand lateral displacement of basal bronchi; lung scan showed perfusion deficit in posterior basal segment LLL Right lower lobectomy Recovered Bronchography: no fillingof 3 basal bronchi Right lower lobectomy and Recovered Right lower lobe vein drains in re-routing of anomalous inferior vena cava belowdiaphragm; venous return RUL venousdrainage partly to right atrium
displacement of the superior segmental bronchus of the left lower lobe and incomplete filling of the basal bronchi, which were tiny and distorted. Lung scan showed absent perfusion in the posterior and medial parts of the left lower lobe. Selective aortography demonstrated a I cm. abnormal artery arising from the aorta at the level of the tenth dorsal vertebra and supplying the inferior part of the left lower lobe (Fig. 4). Venous drainage of this area was demonstrated to the inferior pulmonary vein and the left atrium (Fig. 5). The diagnosis of intralobar sequestration was thus documented. Surgery was recommended but the family declined to accept. However, following recurrence of severe pneumonia 9 months later, the family accepted. The consolidated and adherent left lower lobe was carefully isolated and in the area of the pul-
monary ligament the abnormal systemic artery, which measured approximately I em. in diameter, was followed to its origin from the descending thoracic aorta (Fig. 6). The artery was divided between suture ligatures and from then on the procedure was completed uneventfully. The postoperative course was smooth. The resected lobe showed areas of chronic pneumonia and abscess formation and several bronchial cysts, the largest measuring 4 by 4 em. in diameter. The superior segment was relatively uninvolved. CASE 2. W. C., a 3-year-old white boy, was first admitted to Columbus Children's Hospital on Dec. 3, 1973, with a 6 week history of fever and cough that responded only partially to antibiotics. Chest x-ray demonstrated a homogeneous density in the posterior basal segment of the right lower lobe. Sputum cultures grew Hemophilus influenzae, alpha streptococcus, and Neisseria species. Direct
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Fig. 4. Transfemoral selective arteriogram in case 1 demonstrating the large anomalous systemic artery.
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Fig. 5. Venous phase of angiogram in case 1 showing the venous drainage to the inferior pulmonary vein.
Fig. 6. Operative exposure of anomalous systemic artery isolated in the pulmonary ligament before it enters the sequestration in case 1. smears for acid-fast bacilli and fungus were negative. In spite of continuous treatment with several antibiotics, and pulmonary toilet , no further improvement occurred. Bronchoscopy demonstrated
patency of the right lower lobe bronchus. Bronchography showed a failure of filling of three of the four right basal segments. The child was readm itted 2 months later with another episode of pneumonia ; at this time aortography demon-
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strated a larger systemic artery ansmg from the abdominal aorta at the level of the celiac axis and supplying the posterior basal segment of the right lower lobe (Fig. 7). On April 6, 1974, right thoracotomy was done and the right lower lobe isolated with considerable difficulty from the diaphragm and chest wall owing to dense adhesions. A 5 mm. systemic artery was encountered in the area of the pulmonary ligament. Following control of this vessel, lobectomy was achieved in a routine fashion. The postoperative recovery was uncomplicated. Pathological examination of the resected lobe showed the posterior basal segment to be underinflated and devoid of anthracotic pigmentation (Fig. 8). There were several cystic spaces in this area, the largest measuring 1 em. in diameter. Injection of the abnormal systemic artery was done and showed that the venous drainage was to the inferior pulmonary vein. CASE 3. K. B., a 7-year-old black boy, was admitted to the Columbus Children's Hospital on Jan. 24, 1973, following a motor-car accident. At that time a chest x-ray demonstrated dextrocardia and abnormal vascularity of the right lower lobe. Several subsequent x-rays demonstrated no change in the lung findings. Cardiac catheterization and aortogram revealed two systemic arteries supplying the right lower lobe---one arising from the aorta, at the level of the tenth thoracic vertebra, and the second from the splenic artery. The right lower lobe had no pulmonary arterial supply (Fig. 9) and its venous drainage was to the infradiaphragmatic inferior vena cava by a single large anomalous vein (scimitar vein) (Fig. 10). The venous drainage of the right upper lobe appeared to be at least partially connected to the right atrium. The diagnosis of the scimitar syndrome was made. The child was readmitted in August of 1974 and underwent right lower lobectomy and rerouting of the partially anomalous venous drainage to the left atrium, by direct suture implantation in the left atrium without cardiopulmonary bypass. Postoperative recovery was uneventful.
Discussion
Exclusive supply of an area of the lung by one or more anomalous systemic arteries has been recognized as early as 1777. 8 , 12 Several terms were applied to this entity, including lower accessory lung, anomalous lung, and pulmonary sequestration.v' The latter term is preferable since it conforms with an embryologic theory of traction on-and separation of-a portion of the developing lung bud by the anomalous systemic vessel. An alternative theory
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Fig. 7. Aortogram of case 2 showing the infradiaphragmatic origin of the anomalous artery from the aorta at the level of the celiac axis.
postulates a supernumerary tracheobronchial bud developing from the primitive foregut distal to the normal level. This accessory bud retains its systemic blood supply and mayor may not retain foregut cornmunication. " This theory more adequately explains extralobar sequestration. A third theory, advanced by Smith," postulates that the primary anomaly is deficiency of the pulmonary artery to the basal segments of the lower lobe. This segment would then retain its primitive systemic supply with subsequent cystic degeneration and fibrosis secondary to the high pressure in the systemic circuit. Perhaps several different mechanisms apply to various types of sequestration. In the present series males constituted eight out of the nine cases. Children and adults were represented almost equally. Fifty-five per cent of the sequestrations presented in the posterior basal segment of the left lower lobe, the classical site for sequestration'"; the remaining cases were in the
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Fig. 8. Gross photograph of resected lower lobe of case 2 showing the lack of anthracosis and vague demarcation of the sequestered segment. The vessels and bronchus were cannulated.
Fig. 9. Pulmonary angiogram in case 3 showing the absence of pulmonary artery supply to the right lower lobe.
Fig. 10. Selective catheterization and injection in the "scimitar vein" in case 3 showing its connection to the inferior vena cava.
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right lower lobe. This corresponds with the incidence reported in a review of the literature on sequestration in 1970. 3 Sequestration has also been reported in the upper lobe'" and rarely bilaterally.'; The most frequent clinical presentation is pneumonia in one lower lobe, commonly the left, that only partially responds to conventional therapeutic measures including antibiotics, postural drainage, etc. There is often a history of recurrent infections in the same area of the lung for several years. Bronchiectasis or other bronchial abnormality is suspected, but bronchography often fails to show filling of the corresponding area of the lung, with evidence of distortion and displacement of the nearby bronchi. Bronchiectasis secondary to infection is often present in the neighboring area. The commonest finding in the plain chest roentgenograms has been a mass lesion in the posterior basal segment, with or without surrounding infiltrates. Cystic changes and an air-fluid level have also been noted. Atelectasis and shift of the cardiac silhouette were noted in three cases. The diagnosis was made preoperatively in five of the nine cases by aortography and selective injection in the anomalous systemic vessel. In two of the remaining cases the diagnosis was suspected but aortography not done. A useful screening noninvasive test for patients with suspected sequestration is the lung scan. This demonstrates an area of absent perfusion and, when other data are suggestive, would help select patients to be subjected to arteriography. With increasing awareness of this clinical entity, our last four consecutive patients were definitively diagnosed preoperatively by aortography and/or venous angiography. The level of origin of the systemic artery was from the thoracic aorta in seven out of the nine cases (77 per cent), from the abdominal aorta in one case, and from both the thoracic aorta and the splenic artery in the last case. This corresponds with the experience of several other series in the literature.s- 6, 11, 18 Infradiaphragmatic origin of the feeding artery has been more frequent in
extralobar sequestration, and associated diaphragmatic defect was present in 58 per cent of cases in one series." In a few patients, the left lung was hypoplastic as a result of the associated diaphragmatic hernia. In our series associated congenital anomalies were present in two patients and included dextrocardia, hypoplastic right lung, diaphragmatic hernia, hypoplastic right upper lobe, atrial septal defect, patent ductus arteriosus, and pectus excavatum. Other congenital defects reported include tracheoesophageal fistula," gastric fistula," ectopic gut or pancreatic tissue in the malformation, duplication of gastrointestinal tract, and pericardial cysU 8 The possible hemodynamic significance of the vascular anomaly in pulmonary sequestration was investigated by Solit and associates." They measured the resting cardiac output before and 8 months after resection of an intralobar sequestration in the medial basal segment of the right lower lobe. The cardiac index was 4.24 L. per minute per square meter preoperatively, which was definitely elevated despite the fact that the patient was under basal conditions and his oxygen consumption was not elevated. The postoperative cardiac index dropped to 2.89 L. per minute per square meter. These findings suggest a significant left-to-Ieft shunt produced by the systemic arterial blood flowing directly into tributaries of the pulmonary veins. The patient had no clinical or electrocardiographic criteria of left ventricular hypertrophy or strain. Kergin'" noted marked improvement in the exercise tolerance of one of his patients following removal of the sequestered lower lobe and suggested that in this case the shunting of blood could have been of considerable magnitude, but no physiological measurements were made in that case. The volume of the shunt was generally not huge. It is conceivable that as the patients grow older they might have some harmful effect ultimately on left ventricular function. Three of our patients were asymptomatic at ages 7, 19, and 49, respectively. The only rational treatment of sequestration is to surgically resect the involved area
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of the lung to avoid the sequela of persistent or recurrent infection and possible adverse hemodynamic effect of the left-to-left shunt. The safety of the procedure can be markedly augmented by precise preoperative demonstration of the location and level of the anomalous artery, employing retrograde aortography. The anomalous artery may be quite large and is of the elastic type, resembling the histological structure of a pulmonary artery. This, as well as premature and extensive athromatous change at times, will make surgical handling of the vessel quite precarious. It may be necessary to isolate the aorta above and below the origin of the vessel to obtain optimum control. It should be the habit of every thoracic surgeon to palpate the inferior pulmonary ligament prior to any pulmonary resection since anomalous arteries may arise in this structure even without sequestration." Failure to isolate and control the anomalous systemic artery has in the past resulted in disastrous-and at times fatal-hemorrhage from the stump of the vessel that may retract under the diaphragm.' Unexpected hemorrhage was encountered in the earliest case in this series, explored with a preoperative diagnosis of benign tumor of the diaphragm. A large artery was inadvertently entered while dividing dense adhesions to the retrocardiac area. Fortunately the artery, which arose from the lower thoracic aorta, was quickly clamped and suture ligated, and the extralobar sequestration resected. Although, theoretically, segmental resection would be ideal for intralobar sequestration, generally lobectomy is necessary because of the chronic infection destroying the intersegmental plane, and the presence of bronchiectasis and scarring in the remaining part of the lobe. In this series, seven of the nine patients were treated by lobectomy. Extralobar sequestration can usually be removed completely because of the separate pleural investment. The mortality rate in this series is quite low and this is the experience of other series reported in the literature. The single death in the series was that of a 3-year-old boy
with multiple cardiorespiratory congenital anomalies, including intralobar sequestration. Left basal segmentectomy was followed 12 days later by repair of pectus excavatum; a few hours later sudden respiratory difficulty developed that rapidly ended fatally. Autopsy showed complete atelectasis of the remaining parts of the left lung, pleuritis, and pericarditis. REFERENCES
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10 11 12 13
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Carter, R.: Collective Review. Pulmonary Sequestration, Ann. Thorac. Surg. 7: 68, 1969. De Bakey, M., Arey, J. B., and Brunazzi, R.: Successful Removal of Lower Accessory Lung, J. THoRAc. SURG. 19: 304, 1950. DeParedes, C. G., Pierce, W. S., Johnson, D. G., and Waldhausen, J. A.: Pulmonary Sequestration in Infants and Children: A 20-Year Experience and Review of the Literature, J. Pediatr. Surg. 5: 136, 1970. Fasburg, R. G., Jakubiak, J. V., and Delaney, T. B.: Congenital Partial Absence of the Pericardium, Ann. Thorac. Surg. 5: 171, 1968. Findley, C. W., Jr., and Maier, H. C.: Anomalies of Pulmonary Vessels and Their Significance, With Review of Literature, Surgery 29: 604, 1951. Gerle, R. D., Jaretzki, A., III, Ashley, C. A., and Berne, A. S.: Congenital Broncho-Pulmonary Foregut Malformation, N. Eng\. J. Med. 278: 1413, 1968. Harris, H. H., and Lewis, J.: Anomalies of the Lung With Special Reference to the Dangers of Abnormal Vessels in Lobectomy, J. THoRAe. SURG. 6: 666, 1940. Huber, J. J.: Cited by McCotter. 12 Johnson, J. B., Chun, S. K., Young, R. c., and McCampbell, E. L.: Scimitar Syndrome: Anomalous Venous Drainage of the Right Lung Into the Inferior Vena Cava With Malformation of Pulmonary Structure, J. Natl. Med. Assoc. 64: 297, 1972. Kergin, F. G.: Congenital Cystic Disease of the Lung Associated With Anomalous Arteries, J. THORAC. SURG. 23: 55, 1952. Kilman, 1. W., Battersby, J. S., Hooshang, T., and VelIios, F. : Pulmonary Sequestration, Arch. Surg. 90: 648, 1965. McCotter, R. E.: On the Occurrence of Pulmonary Arteries Arising From the Thoracic Aorta, Anal. Rec. 4: 291, 1910. Nikaidah, H., and Sewenson, 0.: The Ectopic Origin of the Right Main Bronchus From the Esophagus, J. THORAC. CARDIOVASC. SURG. 62: 1, 1971. Pryce, D. M., Sellors, T. H., and Blair, L. G.:
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Intralobar Sequestration of Lung Associated With Abnormal Pulmonary Artery, Br. 1. Surg. 35: 18, 1947. 15 Saegessen, F., and Besson, A.: Extralobar and Intralobar Pulmonary Sequestration of the Upper and Lower Lobes, Chest 63: 69, 1973. 16 Smith, R. A.: Theory of Origin of Intralobar Sequestration, Thorax 11: 10, 1956.
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17 SoIit, R. W., Traimow, W., Wallace, S., and Cohn, H. E.: The Effect of Intralobar Pulmonary Sequestration on Cardiac Output, J. THoRAc. CARDIOVASC. SURG. 49: 844, 1965. 18 Witten, D. M., Clagett, O. T., and Woolner, L. B.: Intralobar Sequestration Involving the Upper Lobes, J. THORAC. CARDIOVASC. SURG. 43: 523, 1962.