Missed cervical dissociation-recognizing and avoiding potential disaster

The Journal of Emergency Medicine, Vol 16, No 2, pp 179-183, 1998 Copyright © 1998 Elsevier Science Inc. Printed in the USA. All rights reserved 0736-4679/98 $19.00 -~- .00

PII S0736-4679(97)00284-9

ELSEVIER

Selected Topics: Emergency Radiology MISSED CERVICAL DISSOCIATION--RECOGNIZING AND AVOIDING POTENTIAL DISASTER Robert F. McLain,

MD,* and Daniel R. Benson, MD 1"

*Department of Orthopaedic Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, and i-Department of Orthopaedic Surgery, University of California, Davis, California Repnnt Address: Robert F. McLain, MD, Staff Surgeon, Department of Orthopaedic Surgery, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195 [] AbstractPComplete cervical disruptions are high-energy injuries often associated with polytrauma and spinal cord injury. Because these injuries disrupt all anterior and posterior stabilizers, they result in a highly unstable spine, and the injuries are usually apparent on screening radiographs. Patients with these injuries must be identified and protected during the multiple diagnostic and surgical procedures they may require during their initial evaluation and treatment. Emergency procedures must be carefully prioritized relative to other life-threatening injuries; formal evaluation of the cervical spine may be carried out before, after, or in stages around other urgently indicated procedures. Until the cervical spine is cleared, careful observation of precautions can avoid disasterous complications in even the most unstable situation. A case of complete cervical disruption in a neurologically intact, hemodynamically unstable patient is presented for discussion. For polytraumatized patients with cervical dissociation, combined anterior and posterior stabilization is the treatment of choice. © 1998 Elsevier Science Inc.

usually the result of high-energy trauma (motor vehicle accidents, falls), frequently associated with other injuries, and rarely are asymptomatic. Subaxial cervical dissociation, the traumatic disruption of all anterior, middle, and posterior ligamentous restraints of the spine, is a rare but extremely unstable injury. Because the forces required to produce such an injury are extreme., cervical dissociation is usually seen in multiply injured patients-the group most likely to require emergent or repeated intubation, multiple operative procedures, and rapid evaluation and transport. Misdiagnosis of this severe disruption can lead to serious complications even if the injury is recognized (1), but failure to recognize these highly unstable injuries predisposes the patient to catastrophic neurological injury during the course of evaluation and treatment. Approximately 30% of all cervical spine injuries are unrecognized at the time of presentation (2,3). The most common causes of missed cervical injury are inadequate screening radiographs, multiple associated injuries and hemodynamic instability, and the intoxication or altered consciousness of the patient. Because polytrauma and severe cervical disruption are both associated with highenergy trauma, it is necessary to consider the two together when assessing the patient with multiple injuries (4). The key to avoiding disaster is to remember the possibility in patients likely to have had a cervical injury.

[] Keywords--cervicai spine; unstable fracture; evaluation; polytrauma

INTRODUCTION

Unstable fractures and dislocations make up a small proportion of all cervical spine injuries. Such injuries are

Selected Topics: Emergency Radiology is coordinated by Jack Keene, MD, of Emergency Treatment Associates,

Poughkeepsie, New York RECEIVED: 26 February 1997; FINAL SUBMISSIONRECEIVED:23 April 1997; ACCEPTED:20 May 1997 179

180

R.F. McLain and I-). R. Benson

Irrespective of what initial tests may show, screening radiographs cannot completely rule out the lesion, and if a reliable history and physical examination cannot be obtained, the possibility of serious injury cannot be excluded. We report a case of a complete cervical dissociation in a neurologically intact patient with screening radiographs that were initially interpreted as showing no cervical injury.

CASE REPORT A 57-year-old woman was admitted to the Emergency Department (EDI after a high-speed motor vehicle accident with multiple fatalities. As the driver of one of the two cars involved in a head on collision, she was ejected from the vehicle, sustaining facial lacerations, a closed head injury, pelvic fracture, and abdominal and extremity trauma. She was hemodynamically unstable at the scene, and was intubated in the field before being transported by helicopter to the Medical Center. On arrival, the patient was awake, responsive, and moving all extremities. Large-bore intravenous lines were placed. Despite rapid volume replacement, the patient remained hemodynamically labile. She was intoxicated, combative, and unable to cooperate with a comprehensive physical examination. She had denied neck pain and paresthesias at the accident site, and, by gesture, denied both pain and tenderness t~ palpation in the ED. A screening anteroposterior chest radiograph was unremarkable, but the abdominal radiograph reveaIed a pelvic ring fracture. The screening lateral cervical radiograph (Figure 1) was obtained during resuscitation, and was interpreted by the radiologist as showing no evidence of fracture or instability. Retropharyngeal swelling seen on this film was attributed to a traumatic intubation. Despite this negative reading, the radiograph did not demonstrate the cervicothoracic junction and was felt to be inadequate to clear the cervical spine. Because of the nature of her accident, her associated injuries, and the inability to carefully question or examine her, the patient was considered to be at high risk for an unrecognized cervical injury. She was maintained in the rigid cervical collar that had been placed at the scene of the accident. The patient remained agitated, and when she made repealed attempts to remove the collar by herself, it became apparent that she was a danger to her own safety. At that point she was chemically paralyzed and placed on a ventilator. Because of her progressive hemodynamic instability, the surgeons decided that a diagnostic peritoneal lavage (DPL) was necessary before any further imaging studies were done. She was taken directly to the operating room where the orotracheal tube was ex-

Figure 1. Screening lateral radiograph taken in the ED does not demonstrate cervicothoracic junction. Although initially considered "unremarkable," marked retropharyngeal swelling and slight splaying of C3-C4 facets can be seen.

changed under fiberoptic control, observing strict spinal precautions. The DPL was grossly positive and the patient underwent an emergent laparotomy, splenectomy, and repair of a liver laceration. After surgery, the patient remained chemically paralyzed until a complete evaluation of head, neck, and pelvis could be completed. Postoperative cervical spine radiographs now demonstrated a severe cervical spine injury that had not been apparent preoperatively. These films demonstrated dissociation of the C3-C4 level, with widening of the disc space anteriorly, and of the facets posteriorly (Figure 2). A cervical magnetic resonance imaging (MRI) scan showed that the soft tissue stabilizers in all three columns were completely disrupted (Figure 3). Because of the severe cervical instability and our concern for post-traumatic complications related to recumbancy, a combined anterior and posterior stabilization was carried out. Anterior discectomy revealed that the anterior and posterior anulus and the posterior longitudinal ligament were entirely disrupted, exposing the dura to view from the front of the spine. Posterior expo-

Cervical [Dissociation in Polytrauma

Figure 2. Oblique radiograph obtained after emergent splenectomy, but before stabilization, shows marked separation of all three columns of the vertebral elements at C3-C4 level.

sure revealed the dura and vertebral arteries as the only intact longitudinal structures, and fusion and facet wiring were performed. On awakening from surgery, the patient was neurologically intact except for mild weakness of the right deltoid, thought to be due to a C4 nerve root injury. She was mobilized in a halo vest postoperatively. At 3 months, the halo was removed and physical therapy prescribed. Radiographs demonstrated excellent alignment and circumpherential fusion. At last follow-up, at 27 months, the patient had full cervical range of motion, no pain, and a normal neurologic examination (Figure 4A,B). Her only limitations were related to sequelae of a fracture/dislocation of the right elbow.

DISCUSSION Patients presenting with complete cervical dissocialion--disruption of all anterior and posterior soft tissue restraints--frequently have a neurologic injury and are

181

Figure 3. MRI demonstrates complete disruption of the disc, with extensive soft tissue injury posteriorly.

commonly quadriplegic (1,2). It is important to protect what functional levels remain, however, as maintenance of root function at the level of instability is important to long-term function. It is even more crucial to recognize the rare patient with complete dissociation (and, hence, a severely unstable spine) and a normal neurologic examination, particularly in the lace of other injuries that may distract care-givers. At our facility, all polytrauma patients are treated as though they have a cervical injury until they are awake and responsive, and cervical trauma is ruled out by history, comprehensive physical examination, and appropriate imaging studies. Three-view screening radiographs are followed by oblique and flexion/extension views (depending on symptoms) when the patient is stable, and augmented by computed tomography (CT) or MRI scan :in any patient with abnormal or ambiguous findings. Treatment is tailored to the level of spinal instability and the demands of the individual patient. Polytrauma patients are difficult to immobilize or brace, tolerate bedrest poorly, and often need to return to the operating room, where the unstable spine may be exposed to potential injury during repetitive intubations

182

R.F. McLain and D. R. Benson

Figure 4A and B. AP and lateral radiographs show combined anterior/posterior instrumentation with Morscher plate and facet wiring 2 years postoperatively.

and positioning. When a three-column injury is recognized in a polytraumatized patient, combined anterior and posterior stabilization is carried out at a single operation, protecting the spine for other surgical procedures and facilitating early mobilization. Timing of surgery is determined based on a hierarchy of life-threatening injuries, using the following protocol. Patients with suspected intraabdominal or thoracic injuries, or significant head injuries are stabilized in a brace, undergo endoscopic nasotracheal intubation, and are maintained in strict spinal precautions until their visceral injuries are treated or an ICP monitoring bolt is placed. Patients with long-bone or other musculoskeletal injuries are placed in skeletal traction before undergoing surgical stabilization of the spine. They can then be repositioned for skeletal stabilization. Combined anterior and posterior procedures are performed under one anesthetic unless it is felt that the patient cannot tolerate both procedures during one sitting. This case illustrates a number of fundamental points crucial to the safe management of cervical spine trauma in the ED. First, radiographs alone cannot rule out a cervical spine injury (5-7). Radiographs may be inadequate because they do not show the eervicothoracic junction, either because the shoulders obscure the field or because the film is positioned improperly. Also, injuries through soft tissue are difficult to see on plain radiographs unless there is displacement or angulation of the bony elemems.

Placed in the supine position, in a cervical orthosis, spinal alignment may be passively restored even though the instability remains. Finally, a single screening view is never adequate to fully evaluate the spine; a full cervical series and, when indicated, CT or MRI scan are warranted whenever there is clinical suspicion of injury. In this case, the lateral radiograph was of good quality and the injury was centered on the film. The cervicothoracic junction was not visible, however, and the fihn was recognized as inadequate, Because this injury was almost exclusively through soft tissue and was nearly anatomically reduced at rest, the radiographic findings of facet and interspinous widening were not appreciated in the ED nor by the radiologist. The retropharyngeal swelling associated with this soft tissue injury was readily apparent, however. Even though this was attributed at the time to intubation trauma, it is a strong indicator of cervical trauma, warranting further evaluation and continued protection. This patient was rushed to surgery before any further studies could be done. Had time permitted a full cervical series, head CT scan with cervical cuts, or an MRI scan, this injury would have been clearly identified. Second, the treating physicians must recognize the characteristic findings associated with a high risk of cervical fracture and maintain precautions until a full evaluation is completed. In this case, the patient presented with 1) high-energy mechanism of injury--a head-on motor vehicle accident: 2) facial lacerations, head lacerations, and closed head injury, signifying di-

Cervical Dissociation in Polytrauma

183

rect trauma to the head and suggesting axial loading and flexion/extension forces involved; 3) intoxication, confusion, and agitation--whether preexisting or due to the injuries sustained, rendering the patient incapable of providing a reliable report or examination; 4) associated extremity and internal injuries causing severe pain-distracting pain masking cervical symptoms; and 5) associated life-threatening injuries, forcing caregivers to act before definitive imaging studies could be completed. These features are associated with both a high likelihood of cervical injury and an increased risk of missing the diagnosis. Although Hoffman et al. and others have concluded that cervical spine radiographs are not necessary in patients without midline neck tenderness, intoxication, altered level of consciousness, or other severely painful injury (8,9), patients presenting with the five features noted above must be carefully evaluated to rule out an occult injury. Until this evaluation is complete, spinal precautions are maintained .just as though the spinal column were grossly unstable. In our case, the patient was successfully managed through intubation, extubation, reintubation, hemodynamic stabilization, and abdominal surgery, with no additional or permanent neural injury. Finally, aggressive surgical treatment is warranted in severe injuries to permit early mobilization and rehabilitation of these multiply injured patients. Some authors recommend anterior plating of the cervical spine as the only treatment of fracture dislocations ( 10,11). However, 64% of anterior fusions fail in the face of posterior instability when instrumentation is not used (l 2-14) and plating alone cannot restore stability to the level of either the intact or posteriorly stabilized spine (15,16). Addi-

tion of the posterior stabilizing procedure, usually an interspinous wiring technique, is the appropriate solution to this problem (13,17,18). The surgical time, blood loss, and low complication rate associated with combined anterior and posterior stabilizations is very acceptable (18), and the advantages of early mobilization far outweigh the prolonged operative time needed to complete the procedures. The combined approach can be safely accomplished under a single anesthetic; aggressive mobilization is then possible and neurologic elements are protected from injury during any subsequent procedures.

CONCLUSIONS Cervical spine injuries are not always apparent on screening radiographs or initial examination, even when severe. Cervical injury must be suspected in any patient with facial lacerations, head injury, high-energy trauma, neck pain, or a dangerous mechanism of injury (ejection, diving, or collision injuries), particularly if the patient is intoxicated, obtunded, or head injured and cannot fully cooperate with either the examination or history. Failure to recognize and treat these highly unstable disruptions may result in significant neurologic injury. In quadriplegic patients, where the risk of further cord damage is limited, residual instability may endanger nerve root levels critical to independent function. In intact patients, failure to protect the spinal column can lead 1o neurologic catastrophe. By observing strict spinal precautions and protective procedures, even the most unstable spine fracture often can be managed without injury to the patient.

REFERENCES I. Cybulski GR, Douglas RA, Meyer PR, Rovin RA. Complications in three-column cervical spine injuries requiring anterior-posterior stabilization. Spine. 1992;17:253-6. 2. Bohlman HH. Acute fractures and dislocations of the cervical spine. J Bone Joint Surg. 1979;61A:1119-42. 3. Reid DC, Henderson R, Saboe L, Miller JDR. Etiology and clinical course of missed spine fractures. J Trauma. 1987:27:980-6. 4. Gerrelts BD, Petersen EU, Mabry J, Petersen SR. Delayed diagnosis of cervical spine injuries. J Trauma. 1991 ;31 : 1622-6. 5. el-Khoury GY, Kathol MH, Daniel WW. Imaging of acute injuries of the cervical spine: value of plain radiography, CT, and MR imaging. Am J Roentgenol. 1995;164:43-50. 6. Vandermark RM. Radiology of the cervical spine in trauma patients: practice pitfalls and recommendations for improving efficiency and communication. Am J Roentgenol. 1990;155:465-72. 7. Walter J, Doris PE, Shaffer MA. Clinical presentation of patients with acute cervical spine injury. Ann Emerg Med. 1984;13:512-15. 8. Hoffinan JR, Schriger DL, Mower W, Luo JS, Zucker M. Low-risk criteria for cervical spine radiography in blunt trauma: a prospective study. Ann Emerg Med. 1992;21:1454-60. 9. McNamara RM, Heine E, Esposito B. Cervical spine injury and

radiography in alert, high-risk patients. ] Emerg Med. 1990:8:17782. 1(1. Aebi M, Zuber K, Marchesi D. Treatment of cervical iujuries wilh anterior plating. Spine. 1991;16:38 45. l 1. Suh PB, Kostuik JP, Esses SI. Anterior cervical plate fixation with the titanium hollow screw system. Spine. 1990; 15:1079- 8 I. 12. Bell GD, Bailey S[. Anterior cervical fusion for trauma. Clin Orthop. 1977;128:155 8. 13. Capen DA, Garland DE, Waters RL. Surgical stabilization of the cervical spine. Clin Orthop. 1985; 196:229-37. 14. Van Peteghem PK, Schweigel JF. The fractured cervical spine rendered unstable by anterior cervical fusion. J Trauma. 1979;19: 110-14. 15. McLain RF, Aretakis A, Moseley TA, Ser P, Benson DR. Subaxial cervical dissociation: Anatomic and biomechanical principles of stabilization. Spine. 1994;19:653 9. 16. Ulrich C. Woesdoerfer O, Ktaff R, Claes L, Wilke HJ. Biomechanics of fixation systems to the cervical spine. Spine. 199l;16:4-9. 17. Cabanela ME, Fbersold MJ. Anterior plate stabilization lot bursting tear-drop fractures of the cervical spine. Spine. 1988;13:,";88-91. 18. McAfee PC, Bohlman HH. One stage anterior cervical decompression and posterior stabilization with circumferential arthrodesis. J Bone Joint Surg. 1989;71A:78-88.