Transmediastinal Penetrating Injuries

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 • 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 Great Vessels Nothing… Heart & Airways Esophagus & others • 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. 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 • 150 000 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 - 35-60% to OR (Richardson et al., 1981) • Management dictated by hemodynamic status

16. But what does ‘stable’ mean?

17. 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 Dx: CXR > PE > OR Group III = SBP < 60 mmHg Dx: ED thoracotomy > death > OR Conclusions: CXR with PE can diagnose TM GSW in 90% of pts. 2000 Indication for immediate OR in stable patients: massive hemothorax & hemopericardium

18. 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. 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: Heart, great vessels Tracheobronchial tree Esophagus Azygous vein Thoracic duct Patients with negative helical CTAs can be safely observed

25. 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. 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 • 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. 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. 2002 May;26(5):539-43. • 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. J Am Coll Surg 1999; 188:290-295 • 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 endanastomosis 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 • 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: 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