1. Transmediastinal Penetrating Injuries
Tanya L. Zakrison, MD, FRCSC, FACS, MPH
Ryder Trauma Center
University of Miami Miller School of Medicine
Florida, USA
Sept. 20, 2014

2. Clinical Case –
24 male patient, found down in a ‘dangerous part’ of São Paulo
EMS / Paramedics arrive
He is breathing, has right-sided subcutaneous emphysema, blood pressure 90/50 mmHg and one obvious gun-shot wound on his chest
5th intercostal space, right side
No other injury

3. What is next?

4. Paramedics Pre-hospital care
most important is prompt transportation to a trauma center
SCOOP AND RUN
A - ETT – careful for tracheobronchial injuries
B - Needle decompression for presumed (tension) pneumothorax
Circulation – IV access, hypotensive resuscitation?
D - Cervical or spinal cord injury – possible
Exposure
Difficult to diagnose in the field
Unless one gun shot was heard, and 2 wounds on chest

5. Nurses ATLS protocol in the trauma bay
Work as a team, excellent communication
Repeat the ABCDEs
Verify ETT placement
Help the surgeons place a tube thoracostomy on decompressed side
Contralateral side too if still hypotensive
Verify that the IV sites are in place, 20 cc/kg crystalloid
Blood (massive transfusion protocol)
ED thoracotomy?
FAST & CXR
Do we need to operate or not?

6. ICU Care Look for occult injuries Bronchoscopy Endoscopy
Missed after surgery
Missed on CT scan
Bronchoscopy
Endoscopy
Echocardiography
Other tests

7. Definitions Mediastinum: (Dorland’s Medical Dictionary)
A median septum or partition
The mass of tissues and organs separating the two lungs, between the sternum in front and vertebral column behind
Transmediastinal Penetrating Injury / GSW
(Richardson et al. 1981)
Opposite hemithoraces have:
Missle entry & exit wounds
Missle entry & retained missile
Traverse Mediastinal Gun Shot Wound
Transverse Mediastinal Gun Shot Wound

8. A transmediastinal penetrating injury does not necessarily mean a penetrating injury to the mediastinum
Do we always have to operate?

9. Anatomy: Mediastinum “Interpleural Space”

10. Anatomy: Mediastinum “Interpleural Space”
Mediastinal Contents
Superior:
the aortic arch; the innominate artery and the thoracic portions of the left common carotid and the left subclavian arteries; the innominate veins and the upper half of the superior vena cava; the left highest intercostal vein; the vagus, cardiac, phrenic, and left recurrent nerves; the trachea, esophagus, and thoracic duct; the remains of the thymus, and some lymph glands.
Anterior:
It contains a quantity of loose areolar tissue, some lymphatic vessels which ascend from the convex surface of the liver, two or three anterior mediastinal lymph glands, and the small mediastinal branches of the internal mammary artery.
Middle:
It contains the heart enclosed in the pericardium, the ascending aorta, the lower half of the superior vena cava with the azygos vein opening into it, the bifurcation of the trachea and the two bronchi, the pulmonary artery dividing into its two branches, the right and left pulmonary veins, the phrenic nerves, and some bronchial lymph glands.
Posterior:
It contains the thoracic part of the descending aorta, the azygos and the two hemiazygos veins, the vagus and splanchnic nerves, the esophagus, the thoracic duct, and some lymph glands.

11. Anatomy: Mediastinum “Interpleural Space”
Mediastinal Contents
Superior:
the aortic arch; the innominate artery and the thoracic portions of the left common carotid and the left subclavian arteries; the innominate veins and the upper half of the superior vena cava; the left highest intercostal vein; the vagus, cardiac, phrenic, and left recurrent nerves; the trachea, esophagus, and thoracic duct; the remains of the thymus, and some lymph glands.
Anterior:
It contains a quantity of loose areolar tissue, some lymphatic vessels which ascend from the convex surface of the liver, two or three anterior mediastinal lymph glands, and the small mediastinal branches of the internal mammary artery.
Middle:
contains the heart enclosed in the pericardium, the ascending aorta, the lower half of the superior vena cava with the azygos vein opening into it, the bifurcation of the trachea and the two bronchi, the pulmonary artery dividing into its two branches, the right and left pulmonary veins, the phrenic nerves, and some bronchial lymph glands.
Posterior:
It contains the thoracic part of the descending aorta, the azygos and the two hemiazygos veins, the vagus and splanchnic nerves, the esophagus, the thoracic duct, and some lymph glands.
Great Vessels
Nothing…
Heart & Airways
Esophagus & others
Other includes: azygous vein, thoracic duct, spinal cord

12. What Do We Worry About As Surgeons?
Injuries that kill early:
Heart
Great vessels
Injuries that kill late:
Tracheobronchial tree
Injuries that kill if missed:
Esophagus
Azygous vein
Injuries that cause morbidity:
Thoracic duct
Spinal cord
Diaphragm

13. Additional Concerns: Associated Injuries: Thorax: Chest wall Lungs
Abdomen:
Any structure
Timing of exploration important
Asensio et al. World J Surgery, 2002
Cardiac Box
Mediastinum
Thoracoabdominal area

14. History of Penetrating Thoracic Trauma
Described in the Edwin Smith Surgical Papyrus, dated 3000 BC, written by Imhotep
First recorded “operation” for thoracic trauma in North America
Cabeza de Vaca, 1635, described removal of arrowhead from the chest wall of an Native American
Contemporary management of transmediastinal penetrating injuries required mandatory exploration Bradley M. Transmediastinal wounds. Am. Surg. 1966;32:847–852

15. Epidemiology of Penetrating Thoracic Trauma
people die a year secondary to trauma
25% of deaths related to thoracic trauma
Urgent operative intervention only required in 2.8% of penetrating thoracic injuries
BUT
Mediastinal penetrating injuries have an increased need for operation
Unstable: 43% of pts - 100% to OR
Stable: 57% of pts % to OR (Richardson et al., 1981)
Management dictated by hemodynamic status

16. But what does ‘stable’ mean?

17. Indication for immediate OR
2000
Can we triage patients based on blood pressure? (OR vs. investigations)
Prospective, N = 68
Group I = SBP > 100 mmHg
Dx: CXR > PE > OR
Group II = SBP 60 – 100 mmHg
Group III = SBP < 60 mmHg
Dx: ED thoracotomy > death > OR
Conclusions:
CXR with PE can diagnose TM GSW in 90% of pts.
Indication for immediate OR
in stable patients:
massive hemothorax &
hemopericardium

18. Remember: 1/5 have an intraabdominal injury
2000
SBP > 100 mmHg?
Investigate (60% do not need surgery)
SBP 60 – 100mmHg?
Resuscitate (50% still do not need surgery)
SBP < 60 mmHg?
Operate (100% need ‘surgery’)
Remember: 1/5 have an intraabdominal injury

19. Prehospital transport times are better
Injury, 2013
Prehospital transport times are better
More patients with TGSW are surviving to hospital
They are ‘sicker’
87% were unstable on arrival (including VSA)
84% required an ED thoracotomy (6% survival)
Only 8% managed non-operatively
Overall mortality 79%
If arrived with vital signs: 24%

20. Main Message Get your ED thoracotomy tray ready
Some stable patients need to go to the OR
Positive pericardial FAST or massive hemothorax
Half (or less) will need surgery
Even if unstable, but all if in extremis
Don’t forget the abdomen

21. Algorithm for All Transmediastinal Injuries
In Extremis:
ED thoracotomy
Hemodynamically unstable:
CXR, FAST, bilateral chest tubes
To the OR
Hemodynamically stable:
Diagnosis (CTA)
Trajectory & injuries
Management
Surgical vs. non-operative

22. How Do We Investigate the Stable Patient?

23. Can helical CT scan reduce the need for further investigations?
N = 24 pts. mediastinal GSWs, HD stable
All pts. received a helical contrast CT scan
12 pts. required further imaging
Bullet tract close to mediastinum – to OR
All other studies negative, no missed injuries
Conclusion:
50% of pts. had a change in management based on CT scan
Helical CT effective to evaluate missile trajectories to assess for mediastinal injuries and avoid unnecessary exams

24. Algorithm for Stable Transmediastinal Injuries
Overt Injuries:
Heart, great vessels
To OR
Occult Injuries:
Tracheobronchial tree
Esophagus
Azygous vein
Thoracic duct
Patients with negative helical CTAs can be safely observed

25. Work up depends on trajectory Prospective, N = 50 pts.
What is our local experience with investigating TM GSWs in stable pts.?
Work up depends on trajectory
Prospective, N = 50 pts.
All pts. had a CXR followed by either:
Cardiac ultrasound, angiography, esophagoscopy, barium swallow and bronchoscopy
8 pts. (16%) found to have a mediastinal injury (cardiac > vascular > tracheoesophageal)
42 pts. (84%) had no mediastinal injury
No difference between groups re: biochemical or clinical status (including chest tube outputs)
Stable pts. may have life-threatening, occult injuries
Aggressive work-up needed in all to avoid missed injuries
NO CTA

26. Burack JH, et al. Triage and outcome of patients with mediastinal penetrating trauma, Ann Thorac Surg. 2007
BACKGROUND:
What is our experience with CXR, ECHO & CTA scans in the evaluation of stable patients with mediastinal penetrating trauma?
METHODS: Retrospective study, N = 207
Unstable patients: OR
Stable patients: CXR, TTE and CTA.
Further testing (angiogram, bronchoscopy, esophagoscopy, esophagogram) based on trajectory
RESULTS:
35% were unstable, 26% died in the emergency department
CTA evaluation was normal in almost 80% of patients
no further treatment needed
Occult injury found in 7% of stable patients
CONCLUSIONS:
Unstable patients require surgery
Stable patients: TTE & chest CTA are effective screening tools
Patients with a negative TTE and CTA results can be observed
If TTE or CTA positive, exclude occult injury

27. Selective investigation depending on the trajectory of the bullet
After thoracic CT scan
Esophagoscopy
Esophageal swallow
Bronchoscopy
Angiography
Mandatory pericardial window
OR:
Selective investigation depending on the trajectory of the bullet
83% of stable pts. had negative CTAs with no missed injuries

28. In the Stable Patient: Is this a transmediastinal penetrating injury?
CXR & physical exam
Are mediastinal structures injured?
Overt injuries requiring OR?
CXR: massive HTX
FAST: positive presumed hemopericardium
Occult injuries requiring OR?
CTA: trajectory
Airways
Esophagus
Vessels
Heart
Left HTX; false negative FAST

29. How Do We Operate?

30. Operative Approach What is injured? Great Vessels Heart Both
Massive hemothorax (unilateral or bilateral)
Large mediastinal hematoma on CXR
Heart
FAST positive
FAST indeterminate, false negative
? Left hemothorax
Ongoing blood loss from chest tube
Both
Both +/- other organs
Other organs (massive tracheobronchial injury)

33. Great Vessel Injury: Where to Cut?

34. Great Vessel Injury: Where to Cut?
Transmediastinal Injuries

35. Don’t forget about the abdomen!

36. N = 254 patients penetrating thoracoabdominal injuries
Asensio JA, Arroyo H Jr, Veloz W, Forno W, Gambaro E, Roldan GA, Murray J, Velmahos G, Demetriades D. Penetrating thoracoabdominal injuries: ongoing dilemma-which cavity and when? World J Surg May;26(5):
N = 254 patients penetrating thoracoabdominal injuries
20% underwent combined thoracotomy and laparotomy
Mortality doubles if combined procedures are required
Persistent hypotension more often in laparotomy followed by thoracotomy group but numbers are too small
Watch persistent hypotension and misleading chest tube outputs

37. Where to Cut? Median Sternotomy
Principles:
“Anywhere you need”
Median Sternotomy +/- cervical extension (R or L):
R subclavian artery, proximal R carotid, brachiocephalic artery, proximal L carotid artery
NOT GOOD FOR L subclavian artery
Too far posterior
3rd ICS anterolateral thoracotomy for proximal control
Supraclavicular incision with resection of medial 3rd of clavicle (distal control)
Median sternotomy (to join the incisions – book / trap door)
Rarely used
GOOD FOR concomitant cardiac injuries

38. Where to Cut? Bilateral Anterolateral Thoracotomies
Utility incision, access to heart and aorta for resuscitation
Can access right lung hilum, ascending aorta, right subclavian vessels
However problematic for L subclavian artery injuries

39. N = 79 pts. with penetrating subclavian or axillary artery injury
J Am Coll Surg 1999; 188:
Retrospective review
N = 79 pts. with penetrating subclavian or axillary artery injury
Conclusion:
Clavicular incision alone provides adequate exposure in 50% of pts. (R and L)
In proximal injuries can use the addition of medial sternotomy
More deaths seen with SCV injuries than SCA

40. Great Vessels – Surgical Principles
Great vessels are fragile, tear easily with dissection, therefore oversew proximal injury on aorta, sew graft into new location on aorta without tension
Use prosthetic graft for vessels > 5 mm vs. saphenous vein (pseudoaneurysm vs. acute rupture)
Dacron for fragile vessels – aorta, SCA

41. Subclavian Artery Injuries
Pitfalls for SCA:
Watch injury to phrenic nerve when dissecting out SCA
Failure of proximal control with 3rd ICS
Failure to document brachial plexus status pre-op
No tunica media, end to end anastomosis doomed to fail
Interposition graft
Damage control:
Definitive repair of injuries with quick & simple techniques in one operation
Abbreviated thoracotomy to restore survivable physiology during a single operation

42. Cardiac Injuries
Unstable pts. may present with tamponade or ongoing blood loss from chest tube
Occult cardiac injuries may be present in 5% to 10% of patients after a TM-GSW Feliciano D, et al. J. Trauma 2000;48:416–422
TTE is the diagnostic test of choice in patients with wounds traversing the anterior mediastinum
When ECHO is used to screen for pericardial fluid it is 97% sensitive, 100% specific, and 99% accurate Nagy K, et al. J. Trauma 1995;38:859 – 862

43. Esophageal Injuries Primary repair even if > 24 hrs
Incidence 0.7% after thoracic gun shot wounds
Transmediastinal gun shot wounds close to spine may result in through and through injury
Delay in repair disastrous
Upper 2/3rds of thoracic esophagus:
Right posterolateral thoracotomy
Distal 1/3:
Left posterolateral approach (7th ICS)
Primary repair even if > 24 hrs
Grillo pleural patch & decortication

44. How long is too long when investigating esophageal injuries?
Retrospective, multicenter study, N = 45 pts.
All pts. to OR, pre-operative evaluation vs. no evaluation
13 hrs vs. 1 hr
Increased complications, LOS in group evaluated (OR > 3)
Conclusion:
Esophageal injuries carry high morbidity and mortality. Diagnostic testing, if done, should be expeditious with delays to definitive management reduced.

45. Tracheobronchial Injuries
Conservative:
Small injuries (< 1/3 diameter of airway)
Asymptomatic
Controlled with tube thoracostomy
No need for PPV
Or place ETT beyond injury with cuff inflated below
Operative:
R posterolateral thoracotomy for injuries of:
Intrathoracic tracheal, right bronchial, and proximal left mainstem bronchus or complex bilateral injuries
L posterolateral thoracotomy for injuries of:
Distal left bronchial injuries > 3 cm from carina
Mobilize anterior and posterior trachea as needed
Interrupted, absorbable sutures (4-0 Vicryl), sutures tied on the outside, end to end anastomosis
Buttress repair with intercostal muscle
Suture chin to chest for healing
Follow up:
Pre-op baseline flow-volume loops
Beware later presentation of ‘adult asthma’
stricture

46. Tracheobronchial Injuries

47. Special Problems Bullet embolization Thoracic duct injury Spinal cord
Azygous vein

48. Bullet (Foreign Body) Embolization
Bullet entry into large diameter vessels of chest
Diagnosis frequently delayed as course of bullet not always apparent
Usually lodges in femoral or iliac vessels
Control site of entry for hemorrhage first
Remove bullet emboli
Surgery
Endovascular methods

49. Special Problems Thoracic duct leaks: Spinal cord injury
Chylothorax
Spinal cord injury
Always assess neurologic function pre-operatively
Neurogenic shock may occur
C > T > L spine

50. Azygous Vein Injury and Repair
N = 22 patients over 40 years
Mortality 36%
Maintain an index of suspicion when there is continued dark venous ooze from behind the pulmonary hilum
Posterolateral thoracotomy best exposure
Ligate the vein unless no IVC

51. In Conclusion: Is this a transmediastinal penetrating injury?
CXR & physical exam
Is your patient unstable?
YES: Bilateral chest tubes, FAST, ED thoracotomy / OR
NO: investigate
Are mediastinal structures injured?
Overt injuries requiring OR?
CXR: massive HTX
FAST: positive presumed hemopericardium
Occult injuries requiring OR?
CTA: trajectory
Airways
Esophagus
Vessels
Heart
Left HTX; false negative FAST

52.
¡Muito obrigado!