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Clinico-radiological correlates in rupture of the major airways
ClinicalRadiology (1991) 43, 371-376
Clinico-radiological Correlates in Rupture of the Major Airways J. A. SPENCER, C. E. R O G E R S and S. WESTABY*
Departments of Radiology and *Cardiothoracic Surgery, John Radcliffe Hospital, Headington, Oxford The plain film appearances of 17 patients with trauma to the major airways were reviewed and correlated with the findings at thoracotomy, bronchoscopy or post-mortem. Predictable radiographic patterns of air leak were discovered which related to the surgical anatomy of the rupture. Airway interruption was seen in two of three patients with laryngeal transection, all showing gross deep and superficial cervico-facial emphysema. Massive mediastinal and deep cervical emphysema without pneumothorax were striking features of tracheal injury. In patients with bronchial rupture all had ipsilateral pneumothorax and most had associated pneumomediastinum, the degree of each component relating to the site of rupture. Only two patients had tension pneumothoraces. These features alone, however, are non-specific and only two of seven patients with bronchial injury showed specific signs of rupture (a fallen lung). An understanding of the mechanisms of injury to the major airways and the predictable resultant patterns of air leak should ensure that such lesions are not overlooked in patients who will usually have sustained multisystem trauma. Spencer, J.A., Rogers, C.E. & Westaby, S. (1991). Clinical Radiology 43, 371-376. Clinico-radiologicat Correlates in Rupture of the Major Airways
The major airways may be injured by both blunt or penetrating trauma. In our clinical practice the former predominate. The incidence of blunt trauma has risen dramatically this century, in pace with the increase in modern high velocity transportation. Injuries from stabbings and gunshot wounds are relatively unusual in the U K but common in certain cities of the USA. The consequences of delayed diagnosis are serious and often fatal. Prompt corrective surgery offers the best chance of avoiding stricturing at the site of injury. In an attempt to define clues to early diagnosis we assessed the immediate clinical and radiological features in a series of patients for whom the site and nature of the airway injury was directly ascertained. P A T I E N T S AND M E T H O D S The plain radiographs of the chest and neck of 17 patients with proven trauma to the major airways were retrospectively analysed independently by two radiologists and a cardiothoracic surgeon. Ttie patients' ages varied from 14 to 57 years with an average age of 23 years, 10 of the patients being less than 25 years of age. Of the 12 cases of blunt trauma, 10 were mate. All but two had sustained severe deceleration injuries in road traffic accidents; one patient having directly injured his neck during a fall and one patient having been crushed. In the group of five patients with penetrating injuries to the major airways, three were female. In all patients the site of injury to the airway was precisely ascertained (Fig. 1): for 15 at thoracotomy (S.W.) during surgical repair of the airway; for one with severe head injury with rigid bronchoscopy alone (S.W.); for the remaining patient with cranio-cervical dislocation by post-mortem. Of the patients with bronchial rupture, six of the seven underwent definitive repair of the airway. Two patients Correspondence to: Dr J. A. Spencer, Department of Radiology, John RadcliffeHospital, Headington,Oxford OX3 9DU.
Fig. 1 -Case 3. Lateral cervical radiograph after endotracheal tube placement. In addition to massive pre-vertebral emphysema there is haemorrhage. Cranio-cervicaldislocation is evident. with associated hepatic trauma had thoraco-abdominal surgery on admission, one of whom had a tension pneumothorax treated by chest drain during initial resuscitation. Four others underwent operative repair of their bronchial injury but only two required chest drain insertion on admission. One patient was treated conservatively by chest drain alone with his injury diagnosed by rigid bronchoscopy.
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Table 1 - Clinical features of the patients with blunt trauma to the major airways
Case
Sex
Age (years)
Mechanism of injury
Site of airway injury
Other injuries
1 2 3 4 5 6 7 8 9 10 11 12
M M M M M M F M M F M M
22 14 36 31 18 23 57 17 19 19 23 35
RTA (car driver) Fall (direct blow) RTA (motorcyclist) RTA (car passenger) RTA (motorcyclist) RTA (car passenger) RTA (run over by a bus) RTA (motorcyclist) RTA (motorcyclist) RTA (motorcyclist) RTA (car driver) RTA (car driver)
Laryngeal crush fracture Laryngeal transection Laryngo-tracheal separation Tracheal transection Tear of posterior tracheal membrane Right main bronchus Right main bronchus Right main bronchus Right middle lobe bronchus Left main bronchus Left main bronchus Left main bronchus
Head injury; rib fractures Pharyngeal disruption Cranio-cervieal dislocation Head injury; sternal fracture Head injury; sternal fracture Pneumopericardium; sternal fracture Ruptured liver; ruptured spleen; flail chest Head injury Ruptured liver; pneumopericardium Ruptured spleen; fractured ribs Ruptured spleen Head injury; flail chest
RTA, road traffic accident.
Table 2 - Clinical features of the patients with penetrating injuries to the major airways
Case
Sex
Age (years)
Mechanism of injury
Site of airway injury
Other injuries
13 14 15 16 17
F M F F M
35 47 22 24 33
Stab wounds Stab wounds RTA (transfixed) Stab wounds (multiple) Gun shot
Cervical trachea Cervical trachea Thoracic trachea Thoracic trachea Thoracic trachea
To neck veins To neck veins Subclavian artery; rib fractures Laceration of liver, spleen, oesophagus Laceration of innominate veins
RTA, road traffic accident.
The p a t t e r n o f air leak into the pleural space, the m e d i a s t i n a l space, the deep cervical a n d superficial s u b c u t a n e o u s tissues was assessed a n d c o r r e l a t e d with the site a n d degree o f injury to the a i r w a y for each patient. T h e sites a n d extent o f a s s o c i a t e d skeletal injuries were recorded. The clinical r e c o r d s o f the patients were reviewed to d e t e r m i n e the m e c h a n i s m o f injury a n d the n a t u r e o f co-existent t r a u m a . RESULTS The clinical details o f the 12 p a t i e n t s with b l u n t t r a u m a are given in T a b l e 1 a n d for the five patients with p e n e t r a t i n g injuries in T a b l e 2. P a t i e n t s w i t h B l u n t T r a u m a to the L a r y n x and T r a c h e a
The d o m i n a n t r a d i o l o g i c a l feature in the five p a t i e n t s with b l u n t t r a u m a to the l a r y n x a n d t r a c h e a was o f m e d i a s t i n a l a n d deep cervical e m p h y s e m a (Fig. 2). T w o o f the three patients with l a r y n g e a l injuries h a d d i s r u p t i o n o f the a i r w a y on the lateral r a d i o g r a p h o f the cervical spine (Fig. 3). O n l y one p a t i e n t sustained a p n e u m o t h o r a x a n d h a d clear evidence o f a co-existent lower chest wall injury with ipsilateral rib fractures. T h e two patients with t h o r a c i c tracheal injury each h a d a f r a c t u r e d sternum. T r a c h e a l r u p t u r e was a t t e n d e d by a massive p n e u m o m e d i a s t i n u m - which increased r a p i d l y in one case with assisted v e n t i l a t i o n - b u t no p n e u m o t h o r a x (Fig. 4). T h e r e was a high incidence o f associated h e a d injury a n d cervical spine injury (Fig. 5) b u t no u p p e r a b d o m i n a l injuries. P a t i e n t s with B l u n t T r a u m a to the B r o n c h i
All o f the seven patients with r u p t u r e o f the b r o n c h i (four on the right, three on the left) h a d p n e u m o t h o r a c e s b u t o n l y two s h o w e d evidence o f tension. F i v e h a d
Fig. 2-Case 1. Laryngeal crush fracture. Anteroposterior cervical radiograph illustrating the extent of deep cervical emphysema.
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373
Fig. 3 - C a s e 2. Lateral cervical radiograph showing disruption of the airway at the laryngotracheal junction. Deep cervical (pre-tracheal) emphysema is present.
Fig. 5 - Anatomical detail of each site of airway rupture was obtained in all cases. A complete transection o f the mediastinal portion of the left
main bronchus is shown (case 10). admission (Figs 6a, b). A tendency to air trapping in affected lungs was observed, presumably as a result of blood clot or a mucosal flap from bronchial injury narrowing the airways. Three patients had injuries to the upper abdominal viscera. Two had evidence of pneumopericardium (Figs 7a, b). The radiological features of the 12 patients with blunt trauma to the major airways are summarized in Table 3 which analyses the pattern of air leak and the associated skeletal injuries.
Patients with Penetrating Injuries
Fig. 4 - Case 5. Tracheal rupture. Chest radiograph following endotracheal tube placement and assisted ventilation. Massive mediastinal and deep cervical emphysema are seen but pneumothorax is absent.
associated pneumomediastinum. Three patients had ipsilateral rib fractures a n d one a fractured sternum. The remaining three had no discernable chest wall injury. Only two patients had evidence of a 'fallen lung' and in one this was only manifest on films two days after
The pattern of injury and air leak in the patients with penetrating injury was related to the site(s) and extent of the resulting lacerations. Three patients had stab wounds and a fourth a low velocity bullet wound. A fifth patient was impaled by a railing after being thrown from his motorcycle. The pattern of air leak mirrored that of patients with blunt t r a u m a but a significant additional finding was that of leakage of blood. All three patients with thoracic tracheal injuries had sizeable haemothoraces in addition to pleural air leaks (Fig. 8). By contrast in none of the patients with blunt trauma was pleural or mediastinal bleeding a significant feature, though the results of bleeding into the lung or airway were recognizable radiotogicalty. In this series of 17 patients two died, one from the effects of head injury, one having sustained craniocervical dislocation. Both had severe laryngeal crush injuries.
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(a)
(a)
(b) Fig. 7 - (a) Case 9. Ruptured right middle lobe bronchus. Chest radiograph with a right tension pneumothorax and a subtle pneumopericardium (arrow). (b) Case 6. Left-side raised decubitus chest film with sizeable pneumopericardium.
(b) Fig. 6 - (a) Case 11. Supine chest radiograph showing a fallen left lung and left tension pneumothorax. The airless left lung has fallen laterally away from the mediastinum. (b) Case 12. Semi-erect chest radiograph 2 days after admission showing a fallen left lung as a rounded opacity in the lower left chest. A flail injury to the left ribs is also present.
DISCUSSION The diagnosis of blunt injury to the major airways relies upon a high degree of clinical suspicion of such injuries in the context of a patient having suffered deceleration or crushing injury (Wiot, 1975). Eleven of the 12 cases in our series had experienced deceleration trauma, 10 in road traffic accidents and one having fallen from a building. The patient with crushing trauma was a woman run over by a bus at relatively low velocity. These mechanisms of trauma place all of the thoracic and abdominal viscera at risk of injury. Post-mortem studies show that major airway injury is rare compared to aortic rupture, the
commonest thoracic injury causing death in deceleration trauma. In a review of 1178 necropsy findings following thoracic injury, 217 cases of large vessel rupture were found and only 33 of tracheobronchial rupture (Berthelsen and Howitz, 1972). The two may co-exist. The population who reach hospital are a self-selected group with less serious injury. Airway rupture is likely to be relatively more common than in post-mortem series but may be overlooked in the presence of associated head injury and/or abdominal injury. Early series suggested that over two-thirds of cases were not diagnosed until stenosis had occurred and declared itself with distal collapse and sepsis (Hood and Sloan, 1959). Surgical repair is most successful if made early. Plain radiographs of the" chest and neck should be obtained in all patients who have sustained trauma likely to cause major airway injury. In our series all patients had a predictable pattern of air leak consequent on the site of rupture. In two of the three cases with laryngeal trauma the airway was seen to be directly interrupted (Fig. 3). Computed tomography has been used to further evaluate the injured larynx and complements laryngoscopy in these patients particularly when there is no air leak but
375
C L I N I C O - R A D I O L O G I C A L C O R R E L A T E S IN R U P T U R E OF THE M A J O R A I R W A Y S T a b l e 3 - P a t t e r n o f air l e a k r e l a t e d to site o f r u p t u r e o f the a i r w a y (blunt t r a u m a )
Case
Site of airway injury
Pneumothorax
Mediastinal emphysema
Deep cervical emphysema
Fractures
1 2 3 4 5 6 7 8 9 I0 11 12
Laryngeal Laryngeal Laryngeal Tracheal Tracheal Right bronchial Right bronchial Right bronchial Right bronchial Left bronchial Left bronchial Left bronchial
+ --+ + + + + T + T +
+ --+ + + + -+ ÷ +
+ + + + + + + -+ + +
L e f t ribs
+ + +
+ +
+ + + + + + +
Cervical Sternal Sternal Sternal R i g h t ribs L e f t ribs L e f t ribs
- - , A b s e n t ; + , m i n o r ; + + , m a j o r ; T, tension.
Fig. 8 - C a s e 16. M u l t i p l e s t a b w o u n d s , t r a c h e a l p e n e t r a t i o n . C h e s t r a d i o g r a p h s h o w i n g a left t e n s i o n h a e m o p n e u m o t h o r a x .
strong clinical features of soft tissue or cartilage injury (Mancuso and Hanafee, 1979). The features of thoracic tracheal rupture are massive mediastinal and deep cervical emphysema (Fig. 4) and this was seen in all cases. The value of the latter finding has been previously emphasized as an early clue to diagnosis (Eijgelaar and H o m a n van der Heide, 1970). When an endotracheal tube is passed there may be evidence of overdistension or abnormal migration of the balloon or tube tip. In one recent series five of seven cases of tracheal rupture were due to intubation and in these the balloon plugged the site of rupture and minimized airleak (Rollins and Tocino, 1987). All cases h a d mediastinal emphysema and pneumothorax was rare and never preceded pneumomediastinum. Pneumothorax will only be seen initially if there has been associated superficial pulmonary laceration trauma. As 80% of cases of bronchial rupture occur within 2.5 cm o f the carina (Chesterman and Satsangi, 1966) it follows that not all cases of br0nchial rupture will result in pneumothorax, particularly on the left where the main bronchus has a longer mediastinal (extrapleural) course. Thus a left main bronchus rupture may appear similar to a thoracic tracheal rupture as in two of our cases where mediastinal air leak overshadowed leak into the pleural space. On the right where the bronchus enters its pleurat sheath soon after its origin pneumothorax is a more constant observation. The presence of a pneumothorax does n o t in itself, however, imply the presence of a bronchial rupture. Pneumothorax is commonly seen with simple superficial pulmonary trauma. A continued pneu-
mothorax following adequate tube drainage was suggestive of the presence of bronchial rupture. Only two tension pneumothoraces were seen. In other series where conservative management or delayed diagnosis have occurred the pneumothorax resulting from bronchial rupture has typically responded satisfactorily to tube drainage (Burke, 1962). Thus the diagnosis of bronchial rupture from plain films alone is more difficult than in the case of laryngeal and tracheal rupture. Only two of our seven cases showed the 'fallen lung' sign previously reported as a specific feature of bronchial rupture (Oh et al., 1969; K u m p e et al., 1970), and in one of these it was not apparent on initial films. Other authors have reported a similar low incidence of specific radiological features of bronchial rupture (Unger et al., 1989). In the supine position the lung falls laterally and posteriorly away from the mediastinum in contrast to simple pneumothorax when the lung collapses medially onto the hilum. In the erect position with bronchial transection the lung tends to fall inferior to its normal point of hilar attachment (Figs 6a, b). The pattern of skeletal injury in association with airway rupture has been emphasized, in particular the presence of fractures to the upper ribs (Burke, 1962). We believe these to simply reflect the site and magnitude of the trauma. Four of the 12 patients had no thoracic cage fractures. Previous reports have also emphasized that there may be no evidence of thoracic cage fracture(Chesterman and Satsangi, 1966). In the three patients with sternal fractures these were not evident on frontal chest radiographs. Head and neck injuries were seen with laryngeal and tracheal trauma; upper abdominal injuries with bronchial rupture. The two cases of pneumopericardium were both seen with injuries to the right bronchi. The significance of this is unclear. This extremely rare injury may be confused with simple pneumomediastinum with which it may coexist and thus may have been underestimated in other series. In the patients with penetrating trauma the site and nature of the injury was more obvious. In two cases of stabbing to the neck only chest radiographs were obtained. One had an obvious 'sucking wound' in the root of the neck. All patients had surgical injuries which required exploration and three had severe blood loss. H a e m o p n e u m o t h o r a x was present in each of the cases of tracheal penetration; little if any pleurat bleeding was seen in the cases of blunt trauma. Predictable patterns of air leak result from major airway rupture. Whilst specific radiological findings are
376
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c o m m o n in r u p t u r e o f the l a r y n x a n d t r a c h e a , t h e y are r e l a t i v e l y u n u s u a l w i t h b r o n c h i a l r u p t u r e . T h e k e y to e a r l y d i a g n o s i s is a r e c o g n i t i o n o f the possibility o f s u c h injuries in the a f t e r m a t h o f d e c e l e r a t i o n o r c r u s h i n g t r a u m a . I n the p r e s e n c e o f t h e p a t t e r n s o f air l e a k described, urgent cardiothoracic or ENT advice should be s o u g h t . REFERENCES
Berthelsen, S & Howitz, P (1972). Injuries of the trachea and bronchi. Thorax, 27, 188-194. Burke, JF (! 962). Early diagnosis of traumatic rupture of the bronchus. Journal of the American Medical Association, 181, 682-686. Chesterman, JT & Satsangi, PN (1966). Rupture of the trachea and bronchi by closed injury. Thorax, 21, 21-27. Eijgelaar, A & Homan van der Heide, JN (1970). A reliable early symptom of bronchial or tracheal rupture. Thorax, 25, 116-125.
Hood, RM & Sloan, HE (1959). Injuries of the trachea and major bronchi. Journal of Thoracic and Cardiovascular Surgery, 38, 458480. Kumpe, DA, Oh, KS & Wyman, SM (1970). A characteristic pulmonary finding in unilateral complete bronchial transection. American Journal of Roentgenology, 110, 704-706. Mancuso, AA & Hanafee, WN (1979). Computed tomography of the injured larynx. Radiology, 133, 139 144. Oh, KS, Fleischner, FG & Wyman, SM (1969). Characteristic pulmonary finding in traumatic complete transection of main-stem bronchus. Radiology, 92, 371 372. Rollins, RJ & Tocino, I (1987). Early radiographic signs of tracheal rupture. American Journal of Roentgenology, 148, 695 698. Unger, JM, Schuchmann, GG, Grossman, JE & Pellett, JR (1989). Tears of the trachea and main bronchi caused by blunt trauma: radiologic findings. American Journal of Roentgenology, 153, 1175 1180. Wiot, JF (1975). The radiological manifestations of blunt chest trauma. Journal of the American Medical Association, 231, 500 503.
Clinico-radiological Correlates in Rupture of the Major Airways J. A. SPENCER, C. E. R O G E R S and S. WESTABY*
Departments of Radiology and *Cardiothoracic Surgery, John Radcliffe Hospital, Headington, Oxford The plain film appearances of 17 patients with trauma to the major airways were reviewed and correlated with the findings at thoracotomy, bronchoscopy or post-mortem. Predictable radiographic patterns of air leak were discovered which related to the surgical anatomy of the rupture. Airway interruption was seen in two of three patients with laryngeal transection, all showing gross deep and superficial cervico-facial emphysema. Massive mediastinal and deep cervical emphysema without pneumothorax were striking features of tracheal injury. In patients with bronchial rupture all had ipsilateral pneumothorax and most had associated pneumomediastinum, the degree of each component relating to the site of rupture. Only two patients had tension pneumothoraces. These features alone, however, are non-specific and only two of seven patients with bronchial injury showed specific signs of rupture (a fallen lung). An understanding of the mechanisms of injury to the major airways and the predictable resultant patterns of air leak should ensure that such lesions are not overlooked in patients who will usually have sustained multisystem trauma. Spencer, J.A., Rogers, C.E. & Westaby, S. (1991). Clinical Radiology 43, 371-376. Clinico-radiologicat Correlates in Rupture of the Major Airways
The major airways may be injured by both blunt or penetrating trauma. In our clinical practice the former predominate. The incidence of blunt trauma has risen dramatically this century, in pace with the increase in modern high velocity transportation. Injuries from stabbings and gunshot wounds are relatively unusual in the U K but common in certain cities of the USA. The consequences of delayed diagnosis are serious and often fatal. Prompt corrective surgery offers the best chance of avoiding stricturing at the site of injury. In an attempt to define clues to early diagnosis we assessed the immediate clinical and radiological features in a series of patients for whom the site and nature of the airway injury was directly ascertained. P A T I E N T S AND M E T H O D S The plain radiographs of the chest and neck of 17 patients with proven trauma to the major airways were retrospectively analysed independently by two radiologists and a cardiothoracic surgeon. Ttie patients' ages varied from 14 to 57 years with an average age of 23 years, 10 of the patients being less than 25 years of age. Of the 12 cases of blunt trauma, 10 were mate. All but two had sustained severe deceleration injuries in road traffic accidents; one patient having directly injured his neck during a fall and one patient having been crushed. In the group of five patients with penetrating injuries to the major airways, three were female. In all patients the site of injury to the airway was precisely ascertained (Fig. 1): for 15 at thoracotomy (S.W.) during surgical repair of the airway; for one with severe head injury with rigid bronchoscopy alone (S.W.); for the remaining patient with cranio-cervical dislocation by post-mortem. Of the patients with bronchial rupture, six of the seven underwent definitive repair of the airway. Two patients Correspondence to: Dr J. A. Spencer, Department of Radiology, John RadcliffeHospital, Headington,Oxford OX3 9DU.
Fig. 1 -Case 3. Lateral cervical radiograph after endotracheal tube placement. In addition to massive pre-vertebral emphysema there is haemorrhage. Cranio-cervicaldislocation is evident. with associated hepatic trauma had thoraco-abdominal surgery on admission, one of whom had a tension pneumothorax treated by chest drain during initial resuscitation. Four others underwent operative repair of their bronchial injury but only two required chest drain insertion on admission. One patient was treated conservatively by chest drain alone with his injury diagnosed by rigid bronchoscopy.
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Table 1 - Clinical features of the patients with blunt trauma to the major airways
Case
Sex
Age (years)
Mechanism of injury
Site of airway injury
Other injuries
1 2 3 4 5 6 7 8 9 10 11 12
M M M M M M F M M F M M
22 14 36 31 18 23 57 17 19 19 23 35
RTA (car driver) Fall (direct blow) RTA (motorcyclist) RTA (car passenger) RTA (motorcyclist) RTA (car passenger) RTA (run over by a bus) RTA (motorcyclist) RTA (motorcyclist) RTA (motorcyclist) RTA (car driver) RTA (car driver)
Laryngeal crush fracture Laryngeal transection Laryngo-tracheal separation Tracheal transection Tear of posterior tracheal membrane Right main bronchus Right main bronchus Right main bronchus Right middle lobe bronchus Left main bronchus Left main bronchus Left main bronchus
Head injury; rib fractures Pharyngeal disruption Cranio-cervieal dislocation Head injury; sternal fracture Head injury; sternal fracture Pneumopericardium; sternal fracture Ruptured liver; ruptured spleen; flail chest Head injury Ruptured liver; pneumopericardium Ruptured spleen; fractured ribs Ruptured spleen Head injury; flail chest
RTA, road traffic accident.
Table 2 - Clinical features of the patients with penetrating injuries to the major airways
Case
Sex
Age (years)
Mechanism of injury
Site of airway injury
Other injuries
13 14 15 16 17
F M F F M
35 47 22 24 33
Stab wounds Stab wounds RTA (transfixed) Stab wounds (multiple) Gun shot
Cervical trachea Cervical trachea Thoracic trachea Thoracic trachea Thoracic trachea
To neck veins To neck veins Subclavian artery; rib fractures Laceration of liver, spleen, oesophagus Laceration of innominate veins
RTA, road traffic accident.
The p a t t e r n o f air leak into the pleural space, the m e d i a s t i n a l space, the deep cervical a n d superficial s u b c u t a n e o u s tissues was assessed a n d c o r r e l a t e d with the site a n d degree o f injury to the a i r w a y for each patient. T h e sites a n d extent o f a s s o c i a t e d skeletal injuries were recorded. The clinical r e c o r d s o f the patients were reviewed to d e t e r m i n e the m e c h a n i s m o f injury a n d the n a t u r e o f co-existent t r a u m a . RESULTS The clinical details o f the 12 p a t i e n t s with b l u n t t r a u m a are given in T a b l e 1 a n d for the five patients with p e n e t r a t i n g injuries in T a b l e 2. P a t i e n t s w i t h B l u n t T r a u m a to the L a r y n x and T r a c h e a
The d o m i n a n t r a d i o l o g i c a l feature in the five p a t i e n t s with b l u n t t r a u m a to the l a r y n x a n d t r a c h e a was o f m e d i a s t i n a l a n d deep cervical e m p h y s e m a (Fig. 2). T w o o f the three patients with l a r y n g e a l injuries h a d d i s r u p t i o n o f the a i r w a y on the lateral r a d i o g r a p h o f the cervical spine (Fig. 3). O n l y one p a t i e n t sustained a p n e u m o t h o r a x a n d h a d clear evidence o f a co-existent lower chest wall injury with ipsilateral rib fractures. T h e two patients with t h o r a c i c tracheal injury each h a d a f r a c t u r e d sternum. T r a c h e a l r u p t u r e was a t t e n d e d by a massive p n e u m o m e d i a s t i n u m - which increased r a p i d l y in one case with assisted v e n t i l a t i o n - b u t no p n e u m o t h o r a x (Fig. 4). T h e r e was a high incidence o f associated h e a d injury a n d cervical spine injury (Fig. 5) b u t no u p p e r a b d o m i n a l injuries. P a t i e n t s with B l u n t T r a u m a to the B r o n c h i
All o f the seven patients with r u p t u r e o f the b r o n c h i (four on the right, three on the left) h a d p n e u m o t h o r a c e s b u t o n l y two s h o w e d evidence o f tension. F i v e h a d
Fig. 2-Case 1. Laryngeal crush fracture. Anteroposterior cervical radiograph illustrating the extent of deep cervical emphysema.
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373
Fig. 3 - C a s e 2. Lateral cervical radiograph showing disruption of the airway at the laryngotracheal junction. Deep cervical (pre-tracheal) emphysema is present.
Fig. 5 - Anatomical detail of each site of airway rupture was obtained in all cases. A complete transection o f the mediastinal portion of the left
main bronchus is shown (case 10). admission (Figs 6a, b). A tendency to air trapping in affected lungs was observed, presumably as a result of blood clot or a mucosal flap from bronchial injury narrowing the airways. Three patients had injuries to the upper abdominal viscera. Two had evidence of pneumopericardium (Figs 7a, b). The radiological features of the 12 patients with blunt trauma to the major airways are summarized in Table 3 which analyses the pattern of air leak and the associated skeletal injuries.
Patients with Penetrating Injuries
Fig. 4 - Case 5. Tracheal rupture. Chest radiograph following endotracheal tube placement and assisted ventilation. Massive mediastinal and deep cervical emphysema are seen but pneumothorax is absent.
associated pneumomediastinum. Three patients had ipsilateral rib fractures a n d one a fractured sternum. The remaining three had no discernable chest wall injury. Only two patients had evidence of a 'fallen lung' and in one this was only manifest on films two days after
The pattern of injury and air leak in the patients with penetrating injury was related to the site(s) and extent of the resulting lacerations. Three patients had stab wounds and a fourth a low velocity bullet wound. A fifth patient was impaled by a railing after being thrown from his motorcycle. The pattern of air leak mirrored that of patients with blunt t r a u m a but a significant additional finding was that of leakage of blood. All three patients with thoracic tracheal injuries had sizeable haemothoraces in addition to pleural air leaks (Fig. 8). By contrast in none of the patients with blunt trauma was pleural or mediastinal bleeding a significant feature, though the results of bleeding into the lung or airway were recognizable radiotogicalty. In this series of 17 patients two died, one from the effects of head injury, one having sustained craniocervical dislocation. Both had severe laryngeal crush injuries.
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(a)
(a)
(b) Fig. 7 - (a) Case 9. Ruptured right middle lobe bronchus. Chest radiograph with a right tension pneumothorax and a subtle pneumopericardium (arrow). (b) Case 6. Left-side raised decubitus chest film with sizeable pneumopericardium.
(b) Fig. 6 - (a) Case 11. Supine chest radiograph showing a fallen left lung and left tension pneumothorax. The airless left lung has fallen laterally away from the mediastinum. (b) Case 12. Semi-erect chest radiograph 2 days after admission showing a fallen left lung as a rounded opacity in the lower left chest. A flail injury to the left ribs is also present.
DISCUSSION The diagnosis of blunt injury to the major airways relies upon a high degree of clinical suspicion of such injuries in the context of a patient having suffered deceleration or crushing injury (Wiot, 1975). Eleven of the 12 cases in our series had experienced deceleration trauma, 10 in road traffic accidents and one having fallen from a building. The patient with crushing trauma was a woman run over by a bus at relatively low velocity. These mechanisms of trauma place all of the thoracic and abdominal viscera at risk of injury. Post-mortem studies show that major airway injury is rare compared to aortic rupture, the
commonest thoracic injury causing death in deceleration trauma. In a review of 1178 necropsy findings following thoracic injury, 217 cases of large vessel rupture were found and only 33 of tracheobronchial rupture (Berthelsen and Howitz, 1972). The two may co-exist. The population who reach hospital are a self-selected group with less serious injury. Airway rupture is likely to be relatively more common than in post-mortem series but may be overlooked in the presence of associated head injury and/or abdominal injury. Early series suggested that over two-thirds of cases were not diagnosed until stenosis had occurred and declared itself with distal collapse and sepsis (Hood and Sloan, 1959). Surgical repair is most successful if made early. Plain radiographs of the" chest and neck should be obtained in all patients who have sustained trauma likely to cause major airway injury. In our series all patients had a predictable pattern of air leak consequent on the site of rupture. In two of the three cases with laryngeal trauma the airway was seen to be directly interrupted (Fig. 3). Computed tomography has been used to further evaluate the injured larynx and complements laryngoscopy in these patients particularly when there is no air leak but
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C L I N I C O - R A D I O L O G I C A L C O R R E L A T E S IN R U P T U R E OF THE M A J O R A I R W A Y S T a b l e 3 - P a t t e r n o f air l e a k r e l a t e d to site o f r u p t u r e o f the a i r w a y (blunt t r a u m a )
Case
Site of airway injury
Pneumothorax
Mediastinal emphysema
Deep cervical emphysema
Fractures
1 2 3 4 5 6 7 8 9 I0 11 12
Laryngeal Laryngeal Laryngeal Tracheal Tracheal Right bronchial Right bronchial Right bronchial Right bronchial Left bronchial Left bronchial Left bronchial
+ --+ + + + + T + T +
+ --+ + + + -+ ÷ +
+ + + + + + + -+ + +
L e f t ribs
+ + +
+ +
+ + + + + + +
Cervical Sternal Sternal Sternal R i g h t ribs L e f t ribs L e f t ribs
- - , A b s e n t ; + , m i n o r ; + + , m a j o r ; T, tension.
Fig. 8 - C a s e 16. M u l t i p l e s t a b w o u n d s , t r a c h e a l p e n e t r a t i o n . C h e s t r a d i o g r a p h s h o w i n g a left t e n s i o n h a e m o p n e u m o t h o r a x .
strong clinical features of soft tissue or cartilage injury (Mancuso and Hanafee, 1979). The features of thoracic tracheal rupture are massive mediastinal and deep cervical emphysema (Fig. 4) and this was seen in all cases. The value of the latter finding has been previously emphasized as an early clue to diagnosis (Eijgelaar and H o m a n van der Heide, 1970). When an endotracheal tube is passed there may be evidence of overdistension or abnormal migration of the balloon or tube tip. In one recent series five of seven cases of tracheal rupture were due to intubation and in these the balloon plugged the site of rupture and minimized airleak (Rollins and Tocino, 1987). All cases h a d mediastinal emphysema and pneumothorax was rare and never preceded pneumomediastinum. Pneumothorax will only be seen initially if there has been associated superficial pulmonary laceration trauma. As 80% of cases of bronchial rupture occur within 2.5 cm o f the carina (Chesterman and Satsangi, 1966) it follows that not all cases of br0nchial rupture will result in pneumothorax, particularly on the left where the main bronchus has a longer mediastinal (extrapleural) course. Thus a left main bronchus rupture may appear similar to a thoracic tracheal rupture as in two of our cases where mediastinal air leak overshadowed leak into the pleural space. On the right where the bronchus enters its pleurat sheath soon after its origin pneumothorax is a more constant observation. The presence of a pneumothorax does n o t in itself, however, imply the presence of a bronchial rupture. Pneumothorax is commonly seen with simple superficial pulmonary trauma. A continued pneu-
mothorax following adequate tube drainage was suggestive of the presence of bronchial rupture. Only two tension pneumothoraces were seen. In other series where conservative management or delayed diagnosis have occurred the pneumothorax resulting from bronchial rupture has typically responded satisfactorily to tube drainage (Burke, 1962). Thus the diagnosis of bronchial rupture from plain films alone is more difficult than in the case of laryngeal and tracheal rupture. Only two of our seven cases showed the 'fallen lung' sign previously reported as a specific feature of bronchial rupture (Oh et al., 1969; K u m p e et al., 1970), and in one of these it was not apparent on initial films. Other authors have reported a similar low incidence of specific radiological features of bronchial rupture (Unger et al., 1989). In the supine position the lung falls laterally and posteriorly away from the mediastinum in contrast to simple pneumothorax when the lung collapses medially onto the hilum. In the erect position with bronchial transection the lung tends to fall inferior to its normal point of hilar attachment (Figs 6a, b). The pattern of skeletal injury in association with airway rupture has been emphasized, in particular the presence of fractures to the upper ribs (Burke, 1962). We believe these to simply reflect the site and magnitude of the trauma. Four of the 12 patients had no thoracic cage fractures. Previous reports have also emphasized that there may be no evidence of thoracic cage fracture(Chesterman and Satsangi, 1966). In the three patients with sternal fractures these were not evident on frontal chest radiographs. Head and neck injuries were seen with laryngeal and tracheal trauma; upper abdominal injuries with bronchial rupture. The two cases of pneumopericardium were both seen with injuries to the right bronchi. The significance of this is unclear. This extremely rare injury may be confused with simple pneumomediastinum with which it may coexist and thus may have been underestimated in other series. In the patients with penetrating trauma the site and nature of the injury was more obvious. In two cases of stabbing to the neck only chest radiographs were obtained. One had an obvious 'sucking wound' in the root of the neck. All patients had surgical injuries which required exploration and three had severe blood loss. H a e m o p n e u m o t h o r a x was present in each of the cases of tracheal penetration; little if any pleurat bleeding was seen in the cases of blunt trauma. Predictable patterns of air leak result from major airway rupture. Whilst specific radiological findings are
376
CLINICAL RADIOLOGY
c o m m o n in r u p t u r e o f the l a r y n x a n d t r a c h e a , t h e y are r e l a t i v e l y u n u s u a l w i t h b r o n c h i a l r u p t u r e . T h e k e y to e a r l y d i a g n o s i s is a r e c o g n i t i o n o f the possibility o f s u c h injuries in the a f t e r m a t h o f d e c e l e r a t i o n o r c r u s h i n g t r a u m a . I n the p r e s e n c e o f t h e p a t t e r n s o f air l e a k described, urgent cardiothoracic or ENT advice should be s o u g h t . REFERENCES
Berthelsen, S & Howitz, P (1972). Injuries of the trachea and bronchi. Thorax, 27, 188-194. Burke, JF (! 962). Early diagnosis of traumatic rupture of the bronchus. Journal of the American Medical Association, 181, 682-686. Chesterman, JT & Satsangi, PN (1966). Rupture of the trachea and bronchi by closed injury. Thorax, 21, 21-27. Eijgelaar, A & Homan van der Heide, JN (1970). A reliable early symptom of bronchial or tracheal rupture. Thorax, 25, 116-125.
Hood, RM & Sloan, HE (1959). Injuries of the trachea and major bronchi. Journal of Thoracic and Cardiovascular Surgery, 38, 458480. Kumpe, DA, Oh, KS & Wyman, SM (1970). A characteristic pulmonary finding in unilateral complete bronchial transection. American Journal of Roentgenology, 110, 704-706. Mancuso, AA & Hanafee, WN (1979). Computed tomography of the injured larynx. Radiology, 133, 139 144. Oh, KS, Fleischner, FG & Wyman, SM (1969). Characteristic pulmonary finding in traumatic complete transection of main-stem bronchus. Radiology, 92, 371 372. Rollins, RJ & Tocino, I (1987). Early radiographic signs of tracheal rupture. American Journal of Roentgenology, 148, 695 698. Unger, JM, Schuchmann, GG, Grossman, JE & Pellett, JR (1989). Tears of the trachea and main bronchi caused by blunt trauma: radiologic findings. American Journal of Roentgenology, 153, 1175 1180. Wiot, JF (1975). The radiological manifestations of blunt chest trauma. Journal of the American Medical Association, 231, 500 503.