CASE REPORT trauma, penetrating neck; thoracic duct
Chylous Drainage From a Stab Wound to the N e c k A 24-year-old man was assaulted and sustained a stab wound to the left lower neck. When he arrived at the emergency department, he was hemodynamically stable. Although the wound had penetrated the platysma, on initial evaluation the patient did not appear to have sustained significant injury Closer examination of the wound revealed chylous drainage, indicating injury to the cervical portion of the thoracic duct. The patient was taken to the operating room for exploration of the wound, during which an injury to the left internal jugular vein was identified and repaired. The thoracic duct, which had been severed, was ligated. The remainder of the patient's hospital course was unremarkable. The consistent association between penetrating injury to the cervical portion of the thoracic duct and injury to neighboring vascular structures is discussed. [Pollack CV Jr, Kolb JC, Griswold JA: Chylous drainage from a stab wound to the neck. Ann Emerg Med December 1990;19:1450-1453.]
INTRODUCTION Controversy persists surrounding the most efficacious management of stab wounds of the neck. Penetration of the platysma is considered by many to be an indication for mandatory exploration, whereas others prefer observation and selective surgery in stable patients who have no signs of major vascular injury. We present the case of a patient with a stab wound at the base of the neck that appeared relatively innocuous in the ED. Although the patient was hemodynamically stable at presentation, there was evidence of chylous drainage from the wound, which placed him at high risk for major vascular injury.
Charles V Pollack, Jr, MA, MD James C Kolb, MD John A Griswold, MD Jackson, Mississippi From the Divisions of Emergency Medicine, and Trauma and Critical Care Surgery, University of Mississippi Medical Center, Jackson. Received for publication December 8, 1989. Revision received April 13, 1990. Accepted for publication May 10, 1990. Address for reprints: Charles V Pollack, Jr, MA, MD, Division of Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505.
CASE REPORT A 24-year-old man presented to the ED by private vehicle approximately 45 minutes after being assaulted by his wife. He had suffered a stab wound to the left neck, and he reported bleeding that had resolved spontaneously. He denied other injuries, loss of consciousness, difficulty in breathing, or dizziness. He admitted to the recent ingestion of alcohol and denied any significant medical or surgical history. He was unable to describe the exact mechanism of injury. There was dried blood on his clothes and all four extremities. His vital signs on arrival were blood pressure of 130/90 m m Hg; pulse, 88; respirations, 20; and temperature, 36.9 C orally. A peripheral venous infusion of lactated Ringer's was started, and the patient was placed on a monitor, which revealed a regular sinus rhythm. The patient's room-air oxygen saturation was 100% by pulse oximetry. On primary survey, the patient was not in acute distress. His airway was patent, and his breathing was unlabored. There was no active bleeding from the neck wound. The patient was coherent and ambulatory. On secondary survey, the patient's head was atraumatic. Eyes, ears, nose, and throat examinations were unremarkable, and the patient's phonation appeared normal. There was the odor of alcohol on his breath. There were two connected, slash-type stab wounds at the base of the left neck, with a total length of approximately 5 cm. The wounds were located above the clavicle, at the level of the cricoid cartilage, and lateral to the lateral aspect of the medial head of the left sternocleidomastoid muscle.
19:12 December 1990
Annals of Emergency Medicine
1450/127
CHYLOUS DRAINAGE Pollack, Kolb & Griswold
F I G U R E 1. Stab w o u n d to the left n e c k as presented in the ED. I n i t i a l l y , the w o u n d s did n o t appear to be of s i g n i f i c a n t depth, but w i t h gentle digital traction applied to the w o u n d (Figure 1), p e n e t r a t i o n of the p l a t y s m a was obvious. Underlying m u s c l e t i s s u e was evident, but t h e r e w e r e no e x p o s e d v a s c u l a r or neural structures. T h e r e was no subcutaneous emphysema around the wound. On careful observation, scant a m o u n t s of a fluid r e s e m b l i n g s k i m m i l k were seen to a c c u m u l a t e repeate d l y in the w o u n d . T h e r e was no bloody drainage. T h e m i l k y fluid was p r e s u m e d to be chyle, draining from an injury to the thoracic duct. T h e neck was supple and w i t h o u t bony tenderness. There was no e d e m a or h e m a t o m a on the left side of the neck, and the trachea was in the m i d l i n e . T h e r e w a s a p a l p a b l e left c a r o t i d pulse, and no b r u i t or t h r i l l c o u l d be a p p r e c i a t e d . T h e r e was n o j u g u l a r v e n o u s d i s t e n s i o n . The chest was clear to auscultation, and the cardiac r h y t h m was regular w i t h no m u r m u r s heard. The abdom e n was soft a n d n o n t e n d e r . T h e genitalia and rectal examinations were unremarkable, although the patient had suffered fecal i n c o n t i n e n c e w h e n he s u s t a i n e d the wound. T h e e x t r e m i t i e s were n o r m a l , i n c l u d i n g symmetric pulses and blood pressures. T h e n e u r o l o g i c e x a m i n a t i o n was n o r m a l to screen of m e n t a l status, c r a n i a l n e r v e f u n c t i o n , s e n s o r i m o t o r f u n c t i o n , deep t e n d o n reflexes, cerebellum, and gait. The left upper extremity was examined closely, and no signs of spinal root or brachial plexus injury could be identified. Laboratory evaluation revealed WBC c o u n t of 11,500; h e m o g l o b i n , 14.0 g/dL; and h e m a t o c r i t , 41.1%. Serum electrolytes, urinalysis, prothrombin time, and partial thromboplastin t i m e were normal. The pat i e n t ' s blood a l c o h o l level was 133 mg%. N e c k and inspiratory and expiratory chest radiographs demo n s t r a t e d n o e v i d e n c e of p n e u mothorax, pleural effusion, subcutaneous air around the wound, or r e t r o p h a r y n g e a l air. A 12-lead EGG was normal. A trauma surgical consultation was obtained. It was d e t e r m i n e d that the p a t i e n t s h o u l d u n d e r g o surgical exploration of the w o u n d because of 128/1451
its location in the m i d d l e zone of the n e c k and the chylous drainage. Preo p e r a t i v e a n g i o g r a p h y was n o t performed. D u r i n g his 4 0 - m i n u t e stay in the ED, the p a t i e n t r e m a i n e d stable. Although there was no external b l e e d i n g , c h y l e c o n t i n u e d to accum u l a t e s l o w l y at t h e b a s e of t h e wound. T h r o u g h a left cervical approach, the stab tract was explored and seen to extend to the junction of the left internal jugular and subclavian veins. This area was exposed, and a small p u n c t u r e w o u n d w i t h overlying clot was identified on the lateral aspect of the distal portion of the left internal jugular vein. T h i s was repaired primarily. T h e t h o r a c i c d u c t was i d e n t i f i e d and found to have been t r a n s e c t e d a p p r o x i m a t e l y 1 c m a w a y f r o m its t e r m i n a t i o n into the left subclavian vein. The duct was ligated. The w o u n d was closed p r i m a r i l y over a l/4-in. Penrose drain. The patient's postoperative course was unremarkable. T h e drain was rem o v e d t w o d a y s after surgery, a n d the patient was discharged h o m e on postoperative day 3. He was asympt o m a t i c in scheduled follow-ups one w e e k and one m o n t h later. Chest radiographs revealed no a c c u m u l a t i o n of p l e u r a l fluid, and w o u n d h e a l i n g was uneventful w i t h no evidence of chylous collection. Annals of Emergency Medicine
DISCUSSION Penetrating cervicothoracic t r a u m a has been a s s o c i a t e d in the surgical literature w i t h m o r t a l i t y rates of bet w e e n 7% and 30%. 1-4 Judicious use of p r e o p e r a t i v e a n g i o g r a p h i c evaluation based on a n a t o m i c l o c a t i o n of t h e e n t r a n c e w o u n d has b e e n reported to i m p r o v e both survival and p o s t o p e r a t i v e m o r b i d i t y , s T h i s has led to some controversy in the reco m m e n d e d m a n a g e m e n t of stable pat i e n t s w i t h p e n e t r a t i n g t r a u m a that v i o l a t e s the p l a t y s m a . H i s t o r i c a l l y , these patients have been subjected to formal e x p l o r a t i o n . C u r r e n t controversy concerns stab w o u n d s and deep l a c e r a t i o n s of t h e neck, w h i c h m a y be a m e n a b l e to n o n o p e r a t i v e m a n agement. G u n s h o t w o u n d s are diffic u l t to m a n a g e e x p e c t a n t l y due to the p o t e n t i a l for blast effects that are n o t always c l i n i c a l l y predictable. In the d e v e l o p m e n t of protocols for m a n a g e m e n t of stab w o u n d s to the neck, a s y s t e m of a n a t o m i c classification has been proposed based on predicted operative findings and outcomes. The n e c k is divided into three zones: high (zone III), above the angle of the mandible; low (zone I), variab l y defined as b e l o w the b o t t o m of the cricoid cartilage s or the sternal notch; 6 and m i d d l e (zone lI), between high and l o w (Figure 2). Z o n e I encompasses the thoracic outlet, where hemorrhage from injury to the great 19:12 December 1990
FIGURE 2. A n a t o m i c zones of the n e c k for categorizing entry w o u n d s in penetrating trauma. Upper boundary of zone I has been defined as the base of the cricoid cartilage 5 (zone L above), or the sternal notch 6 (zone I').
Z o n e III
Z o n e II
Zone I
[
Zone f 2
vessels is the greatest risk. If the patient is stable, preoperative aortography is recommended. Evaluation of the upper aerodigestive tracts by endoscopy or contrast radiology is also indicated. Zone III injuries should be evaluated preoperatively by carotid angiography, if possible, to determine both carotid integrity and the status of the intracerebral circulation. 7 In the past, middle-zone injuries have b e e n e x p l o r e d w i t h o u t angiographic evaluation. Although controversy persists in the surgical literature, 8 selective management of stable patients with zone II injuries that penetrate the platysma but show no evidence of major vascular injury has been r e c o m m e n d e d by some authors.9,1° Aside from vascular injury, consideration must also be given to the possibility of associated neurologic, upper airway, and esophageal injuries in these patients. There are certain indications at presentation that mandate operative exploration of these wounds, such as hematoma, bruit or thrill, subcutaneous air, and alterations of voice and/or upper airway integrity. To this list should be added clinical evidence of thoracic duct injury. Thoracic duct injuries in penetrating cervical trauma are rare. Among six seriesX-S,11 from the 1970s of patients with penetrating cervicothoracic injuries that collectively 19:12 December 1990
reported 791 major vascular injuries a m o n g 1,088 patients, there were only 15 thoracic duct injuries. The duct may be injured in zone II, where it may rise as high as 4 cm above the clavicle, 12 or in zone I, at its point of entry into the venous system. Because of its intimate anatomic relationships with major vascular structures in both zones, any apparent ductal injury should prompt surgical exploration of the wound. The jugular and subclavian venous systems must be inspected carefully; arterial injury is usually obvious. Because none of the reported cervical ductal injuries from penetrating injuries2,S, 11-17 have occurred in isolation from associated injury, a high index of suspicion m u s t be m a i n t a i n e d even in otherwise i n n o c u o u s left neck wounds in stable patients. Uncertainty about the nature of unusual drainage from such a wound may be relieved in the ED by staining the fluid with Sudan III dye and confirming the presence of fat globules. In addition to the morbidity and mortality of associated injuries, a missed ductal injury nearly always results in at least one diverse complication. A chylous fistula may form, with the attendant risk of metabolic and nutritional deficiencies, infection or suture line breakdown, is A collection of chyle ( " c h y l o m a " ) 19 may form in the neck and persist deAnnals of Emergency Medicine
spite repeated drainage procedures until the source is recognized and definitive therapy undertaken. Chylomata are often themselves complicated by chylous fistula. C h y l o u s leakage into the pleural space (chylothorax)1347,20, 21 may also occur after cervical injury, but it usually follows intrathoracic trauma to the duct. Isolated cervical ductal injuries have been reported from iatrogenic causes, most often related to radical neck dissections. 18 In cervical c h y l o m a or cervical chylous fistula, ligation of the thoracic duct is indicated to avoid potential complications. Ligation of the cervical portion of the duct causes no k n o w n morbidity. 12,13,t8,19 Microscopic repair of the duct may be attempted after iatrogenic injury, but it is n o t advisable in the m u l t i p l e t r a u m a v i c t i m . T r a u m a t i c chylothorax more often results from blunt cervicothoracic injury or inadvertent direct operative trauma and is seldom a complication of ligation of the cervical portion of the duct. Chylothorax often may be treated conservatively by drainage and dietary manipulation but may require transthoracic ligation.
SUMMARY We describe the case of a patient with a middle-zone stab wound to the neck who had a thoracic duct injury evident from external chylous drainage but no direct evidence of major vascular injury. Penetrating ductal injury is almost invariably associated with significant vascular injury, and if unrecognized is itself fraught with complications. Injury to the cervical portion of the thoracic duct is rare, but it is usually externally apparent. When recognized, as in our patient, exploration of the neck wound is mandatory, even in a stable patient with no other apparent injuries.
REFERENCES
1. BrickerDL, Noon GP, Beall AC, et ah Vascular injuries of the thoracic outlet. J Trauma 1970;10:1-15. 1452/129
CHYLOUS DRAINAGE Pollack, Kolb & Griswold
2. Flint LM, Snyder WH, Perry MO, et al: Management of major vascular injuries in the base of the neck: An II-year experience with 146 cases. Arch Surg 1973;106:407-413.
8. Meyer JP, Barrett JA, Schulcr JJ, et al: Mandatory vs selective exploration for penetrating neck trauma: A prospective assessment. Arch Surg 1987;122:592-597.
15. Crandall LA, Barker SB, Graham DG: A study of the lymph flow from a patient with a thoracic duct fistula. Gastroenterology 1943;
3. Hewitt RL, Smith AD, Becker ML, et al: Penetrating vascular injuries of the thoracic outlet. Surgery 1974;76:715-722.
9. Wood J, Fabian TC, Mangiante EC: Penetrating neck injuries: Recommendations for selective management. J Trauma 1989;29:602-605.
16. T o u r o f f ASW: T h e m a n a g e m e n t of chylothorax (letter). J Thorac Surg 1950;19:723.
4. Schaff HV, Brawlcy RK: Operative management of penetrating vascular injuries of the thoracic outlet. Surgery 1977;82:182-191.
10. Cohen ES, Breauz CW, Johnson PN, et al: Penetrating neck injuries: Experience with selective exploration. South Med J 1987;80:26-28.
5. Roon AJ, Christensen N: Evaluation and treatment of penetrating cervical injuries. J Trauma 1979;19:391-397.
11. Sheely CH, Mattox KL, Reul GJ, et al: Current concepts in the management of penetrating neck trauma. J Trauma 1975;15:895-900.
6. Saletta JD, Lowe RJ, Lim LT, et al: Penetrating trauma to the neck. J Trauma 1976;16: 579-587.
12. Penn I: Injuries of the cervical portion of the thoracic duct. Br J Surg 1962;50:19-22.
7. Campbell WH, Cantrill SV: Neck injuries, in Rosen P, Baker FJ, Barkin RM, et al (eds): Emergency Medicine: Concepts and Clinical Practice, ed 2. St Louis, CV Mosby, 1988, p 419-430.
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13. Brewer LA: Surgical management of lesions of the thoracic duct. A m J Surg 1955;90:210-227. 14. Loe RH: Injuries of the thoracic duct. Arch Surg 1946;53:448-455.
Annals of Emergency Medicine
1:1040-1048.
17. Ong GB, Lee TC: Traumatic chylothorax: Report of a case. Br J Surg 1960;47:570-573. 18. Stubbs WK, Tabb HG: Thoracic duct injuries. South Med J 1977;70:1062-1063. 19. Sinclair D, Woods E, Saibil EA, et al: "Chyloma": A persistent post-traumatic collection in the left supraclavicular region. J Trauma 1987;27:567-569. 20. Goorwitch J: Traumatic chylothorax and thoracic duct ligation. J Thorac Surg 1955; 29:467-479. 21. Ramzy AL, Rodriguez A, Cowley RA: Pitfalls in the management of traumatic chylothorax. J Trauma 1982;22:513-515.
19:12 December 1990
Chylous Drainage From a Stab Wound to the N e c k A 24-year-old man was assaulted and sustained a stab wound to the left lower neck. When he arrived at the emergency department, he was hemodynamically stable. Although the wound had penetrated the platysma, on initial evaluation the patient did not appear to have sustained significant injury Closer examination of the wound revealed chylous drainage, indicating injury to the cervical portion of the thoracic duct. The patient was taken to the operating room for exploration of the wound, during which an injury to the left internal jugular vein was identified and repaired. The thoracic duct, which had been severed, was ligated. The remainder of the patient's hospital course was unremarkable. The consistent association between penetrating injury to the cervical portion of the thoracic duct and injury to neighboring vascular structures is discussed. [Pollack CV Jr, Kolb JC, Griswold JA: Chylous drainage from a stab wound to the neck. Ann Emerg Med December 1990;19:1450-1453.]
INTRODUCTION Controversy persists surrounding the most efficacious management of stab wounds of the neck. Penetration of the platysma is considered by many to be an indication for mandatory exploration, whereas others prefer observation and selective surgery in stable patients who have no signs of major vascular injury. We present the case of a patient with a stab wound at the base of the neck that appeared relatively innocuous in the ED. Although the patient was hemodynamically stable at presentation, there was evidence of chylous drainage from the wound, which placed him at high risk for major vascular injury.
Charles V Pollack, Jr, MA, MD James C Kolb, MD John A Griswold, MD Jackson, Mississippi From the Divisions of Emergency Medicine, and Trauma and Critical Care Surgery, University of Mississippi Medical Center, Jackson. Received for publication December 8, 1989. Revision received April 13, 1990. Accepted for publication May 10, 1990. Address for reprints: Charles V Pollack, Jr, MA, MD, Division of Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505.
CASE REPORT A 24-year-old man presented to the ED by private vehicle approximately 45 minutes after being assaulted by his wife. He had suffered a stab wound to the left neck, and he reported bleeding that had resolved spontaneously. He denied other injuries, loss of consciousness, difficulty in breathing, or dizziness. He admitted to the recent ingestion of alcohol and denied any significant medical or surgical history. He was unable to describe the exact mechanism of injury. There was dried blood on his clothes and all four extremities. His vital signs on arrival were blood pressure of 130/90 m m Hg; pulse, 88; respirations, 20; and temperature, 36.9 C orally. A peripheral venous infusion of lactated Ringer's was started, and the patient was placed on a monitor, which revealed a regular sinus rhythm. The patient's room-air oxygen saturation was 100% by pulse oximetry. On primary survey, the patient was not in acute distress. His airway was patent, and his breathing was unlabored. There was no active bleeding from the neck wound. The patient was coherent and ambulatory. On secondary survey, the patient's head was atraumatic. Eyes, ears, nose, and throat examinations were unremarkable, and the patient's phonation appeared normal. There was the odor of alcohol on his breath. There were two connected, slash-type stab wounds at the base of the left neck, with a total length of approximately 5 cm. The wounds were located above the clavicle, at the level of the cricoid cartilage, and lateral to the lateral aspect of the medial head of the left sternocleidomastoid muscle.
19:12 December 1990
Annals of Emergency Medicine
1450/127
CHYLOUS DRAINAGE Pollack, Kolb & Griswold
F I G U R E 1. Stab w o u n d to the left n e c k as presented in the ED. I n i t i a l l y , the w o u n d s did n o t appear to be of s i g n i f i c a n t depth, but w i t h gentle digital traction applied to the w o u n d (Figure 1), p e n e t r a t i o n of the p l a t y s m a was obvious. Underlying m u s c l e t i s s u e was evident, but t h e r e w e r e no e x p o s e d v a s c u l a r or neural structures. T h e r e was no subcutaneous emphysema around the wound. On careful observation, scant a m o u n t s of a fluid r e s e m b l i n g s k i m m i l k were seen to a c c u m u l a t e repeate d l y in the w o u n d . T h e r e was no bloody drainage. T h e m i l k y fluid was p r e s u m e d to be chyle, draining from an injury to the thoracic duct. T h e neck was supple and w i t h o u t bony tenderness. There was no e d e m a or h e m a t o m a on the left side of the neck, and the trachea was in the m i d l i n e . T h e r e w a s a p a l p a b l e left c a r o t i d pulse, and no b r u i t or t h r i l l c o u l d be a p p r e c i a t e d . T h e r e was n o j u g u l a r v e n o u s d i s t e n s i o n . The chest was clear to auscultation, and the cardiac r h y t h m was regular w i t h no m u r m u r s heard. The abdom e n was soft a n d n o n t e n d e r . T h e genitalia and rectal examinations were unremarkable, although the patient had suffered fecal i n c o n t i n e n c e w h e n he s u s t a i n e d the wound. T h e e x t r e m i t i e s were n o r m a l , i n c l u d i n g symmetric pulses and blood pressures. T h e n e u r o l o g i c e x a m i n a t i o n was n o r m a l to screen of m e n t a l status, c r a n i a l n e r v e f u n c t i o n , s e n s o r i m o t o r f u n c t i o n , deep t e n d o n reflexes, cerebellum, and gait. The left upper extremity was examined closely, and no signs of spinal root or brachial plexus injury could be identified. Laboratory evaluation revealed WBC c o u n t of 11,500; h e m o g l o b i n , 14.0 g/dL; and h e m a t o c r i t , 41.1%. Serum electrolytes, urinalysis, prothrombin time, and partial thromboplastin t i m e were normal. The pat i e n t ' s blood a l c o h o l level was 133 mg%. N e c k and inspiratory and expiratory chest radiographs demo n s t r a t e d n o e v i d e n c e of p n e u mothorax, pleural effusion, subcutaneous air around the wound, or r e t r o p h a r y n g e a l air. A 12-lead EGG was normal. A trauma surgical consultation was obtained. It was d e t e r m i n e d that the p a t i e n t s h o u l d u n d e r g o surgical exploration of the w o u n d because of 128/1451
its location in the m i d d l e zone of the n e c k and the chylous drainage. Preo p e r a t i v e a n g i o g r a p h y was n o t performed. D u r i n g his 4 0 - m i n u t e stay in the ED, the p a t i e n t r e m a i n e d stable. Although there was no external b l e e d i n g , c h y l e c o n t i n u e d to accum u l a t e s l o w l y at t h e b a s e of t h e wound. T h r o u g h a left cervical approach, the stab tract was explored and seen to extend to the junction of the left internal jugular and subclavian veins. This area was exposed, and a small p u n c t u r e w o u n d w i t h overlying clot was identified on the lateral aspect of the distal portion of the left internal jugular vein. T h i s was repaired primarily. T h e t h o r a c i c d u c t was i d e n t i f i e d and found to have been t r a n s e c t e d a p p r o x i m a t e l y 1 c m a w a y f r o m its t e r m i n a t i o n into the left subclavian vein. The duct was ligated. The w o u n d was closed p r i m a r i l y over a l/4-in. Penrose drain. The patient's postoperative course was unremarkable. T h e drain was rem o v e d t w o d a y s after surgery, a n d the patient was discharged h o m e on postoperative day 3. He was asympt o m a t i c in scheduled follow-ups one w e e k and one m o n t h later. Chest radiographs revealed no a c c u m u l a t i o n of p l e u r a l fluid, and w o u n d h e a l i n g was uneventful w i t h no evidence of chylous collection. Annals of Emergency Medicine
DISCUSSION Penetrating cervicothoracic t r a u m a has been a s s o c i a t e d in the surgical literature w i t h m o r t a l i t y rates of bet w e e n 7% and 30%. 1-4 Judicious use of p r e o p e r a t i v e a n g i o g r a p h i c evaluation based on a n a t o m i c l o c a t i o n of t h e e n t r a n c e w o u n d has b e e n reported to i m p r o v e both survival and p o s t o p e r a t i v e m o r b i d i t y , s T h i s has led to some controversy in the reco m m e n d e d m a n a g e m e n t of stable pat i e n t s w i t h p e n e t r a t i n g t r a u m a that v i o l a t e s the p l a t y s m a . H i s t o r i c a l l y , these patients have been subjected to formal e x p l o r a t i o n . C u r r e n t controversy concerns stab w o u n d s and deep l a c e r a t i o n s of t h e neck, w h i c h m a y be a m e n a b l e to n o n o p e r a t i v e m a n agement. G u n s h o t w o u n d s are diffic u l t to m a n a g e e x p e c t a n t l y due to the p o t e n t i a l for blast effects that are n o t always c l i n i c a l l y predictable. In the d e v e l o p m e n t of protocols for m a n a g e m e n t of stab w o u n d s to the neck, a s y s t e m of a n a t o m i c classification has been proposed based on predicted operative findings and outcomes. The n e c k is divided into three zones: high (zone III), above the angle of the mandible; low (zone I), variab l y defined as b e l o w the b o t t o m of the cricoid cartilage s or the sternal notch; 6 and m i d d l e (zone lI), between high and l o w (Figure 2). Z o n e I encompasses the thoracic outlet, where hemorrhage from injury to the great 19:12 December 1990
FIGURE 2. A n a t o m i c zones of the n e c k for categorizing entry w o u n d s in penetrating trauma. Upper boundary of zone I has been defined as the base of the cricoid cartilage 5 (zone L above), or the sternal notch 6 (zone I').
Z o n e III
Z o n e II
Zone I
[
Zone f 2
vessels is the greatest risk. If the patient is stable, preoperative aortography is recommended. Evaluation of the upper aerodigestive tracts by endoscopy or contrast radiology is also indicated. Zone III injuries should be evaluated preoperatively by carotid angiography, if possible, to determine both carotid integrity and the status of the intracerebral circulation. 7 In the past, middle-zone injuries have b e e n e x p l o r e d w i t h o u t angiographic evaluation. Although controversy persists in the surgical literature, 8 selective management of stable patients with zone II injuries that penetrate the platysma but show no evidence of major vascular injury has been r e c o m m e n d e d by some authors.9,1° Aside from vascular injury, consideration must also be given to the possibility of associated neurologic, upper airway, and esophageal injuries in these patients. There are certain indications at presentation that mandate operative exploration of these wounds, such as hematoma, bruit or thrill, subcutaneous air, and alterations of voice and/or upper airway integrity. To this list should be added clinical evidence of thoracic duct injury. Thoracic duct injuries in penetrating cervical trauma are rare. Among six seriesX-S,11 from the 1970s of patients with penetrating cervicothoracic injuries that collectively 19:12 December 1990
reported 791 major vascular injuries a m o n g 1,088 patients, there were only 15 thoracic duct injuries. The duct may be injured in zone II, where it may rise as high as 4 cm above the clavicle, 12 or in zone I, at its point of entry into the venous system. Because of its intimate anatomic relationships with major vascular structures in both zones, any apparent ductal injury should prompt surgical exploration of the wound. The jugular and subclavian venous systems must be inspected carefully; arterial injury is usually obvious. Because none of the reported cervical ductal injuries from penetrating injuries2,S, 11-17 have occurred in isolation from associated injury, a high index of suspicion m u s t be m a i n t a i n e d even in otherwise i n n o c u o u s left neck wounds in stable patients. Uncertainty about the nature of unusual drainage from such a wound may be relieved in the ED by staining the fluid with Sudan III dye and confirming the presence of fat globules. In addition to the morbidity and mortality of associated injuries, a missed ductal injury nearly always results in at least one diverse complication. A chylous fistula may form, with the attendant risk of metabolic and nutritional deficiencies, infection or suture line breakdown, is A collection of chyle ( " c h y l o m a " ) 19 may form in the neck and persist deAnnals of Emergency Medicine
spite repeated drainage procedures until the source is recognized and definitive therapy undertaken. Chylomata are often themselves complicated by chylous fistula. C h y l o u s leakage into the pleural space (chylothorax)1347,20, 21 may also occur after cervical injury, but it usually follows intrathoracic trauma to the duct. Isolated cervical ductal injuries have been reported from iatrogenic causes, most often related to radical neck dissections. 18 In cervical c h y l o m a or cervical chylous fistula, ligation of the thoracic duct is indicated to avoid potential complications. Ligation of the cervical portion of the duct causes no k n o w n morbidity. 12,13,t8,19 Microscopic repair of the duct may be attempted after iatrogenic injury, but it is n o t advisable in the m u l t i p l e t r a u m a v i c t i m . T r a u m a t i c chylothorax more often results from blunt cervicothoracic injury or inadvertent direct operative trauma and is seldom a complication of ligation of the cervical portion of the duct. Chylothorax often may be treated conservatively by drainage and dietary manipulation but may require transthoracic ligation.
SUMMARY We describe the case of a patient with a middle-zone stab wound to the neck who had a thoracic duct injury evident from external chylous drainage but no direct evidence of major vascular injury. Penetrating ductal injury is almost invariably associated with significant vascular injury, and if unrecognized is itself fraught with complications. Injury to the cervical portion of the thoracic duct is rare, but it is usually externally apparent. When recognized, as in our patient, exploration of the neck wound is mandatory, even in a stable patient with no other apparent injuries.
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