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SPINAL TRAUMA

 

 

Clearance of Cervical Spine Injury - Unconscious, Intubated Patients
Karim Brohi, trauma.org 7:4, April 2002

Unconscious, Intubated Patients

The odontoid view is unreliable in intubated patients.

Clinical examination is impossible in the unconscious patient.

Plain film radiology cannot exclude ligamentous instability.

Initial Assessment of Spinal Trauma

Introduction
Spinal Stabilization
Clinical Clearance
Conscious Patients
Unconscious Patients
Thoracic & Lumbar Spine
Paediatric Spinal Injury

The standard radiological examination of the cervical spine in the unconscious, intubated patient is :

  • Lateral cervical spine film
  • Antero-posterior cervical spine film
  • CT scan of occiput - C3

The open-mouth odontoid radiograph is inadequate in intubated patients and will miss up to 17% of injuries to the upper cervical spine.

Thin-cut (2mm) axial CT scanning on specific bone windows, with sagittal and coronal reconstruction should be used to evaluate abnormal, suspicious or poorly visualised areas on plain radiology. With technically adequate studies and experienced interpretation, the combination of plain radiology and directed CT scanning provides a false negative rate of less than 0.1%. The scan should include the entire vertebral body above and below the region of interest, as these must be undamaged for subsequent internal fixation.

Ligamentous Instability

Clearance of the spine in unconscious patients is limited by the lack of clinical information. The incidence of unstable spinal injury in adult, intubated trauma patients is around 10.2%. The incidence of unstable, occult spinal trauma (not visible on plain films is around 2.5%. The options for full clearance of cervical spine injury are:

  • Continue precautions until fully conscious
  • Magnetic Resonance Imaging
  • Dynamic Flexion-Extension Fluoroscopy
  • CT Scan whole cervical spine

Continue spinal precautions until fully conscious.

Where the patient is expected to regain full consciousness in the following 24-48 hours, patients can be nursed with full spinal precuations. Once the patient has returned to full consciousness, clinical examination can exclude significant ligamentous injury.

Prolonged spinal immobilisation in critically ill patients leads to decubitus ulcers and deep venous thromboses while compromising nursing care, respiratory support and the management of traumatic brain injury.

A semi-rigid collar is not necessary in the adequately sedated, ventilated patient, and may increase intracranial pressure in patients with traumatic brain injury.

Magnetic Resonance Imaging

MRI is extremely sensitive at detecting soft tissue injuries without stressing the cervical spine. However the significance of such injuries with regards to the clinical stability of the spine is not clear, and the number of false positive examinations is high. MRI of ventilated patients is a significant undertaking requiring special non-ferromagnetic equipment. However the increasing use of MRI for critically ill patients is making this equipment cheaper and more widely available. Possibly because of the difficulties associated with undertaking routine MRI scans in these patients, there have been few good studies on the use of MRI in clearing the cervical spine in unconscious patients.

Dynamic Flexion-Extension Fluoroscopy

Fluoroscopy Passive dynamic flexion/extension stressing of the cervical spine, performed by an experienced clinician, should reveal most significant ligamentous injuries. Several centres have reported their results, and some guidelines give primary support to the use of dynamic fluoroscopy in clearance of the spine in unconscious patients.

However, there are significant difficulties in performing flexion/extension imaging routinely on the intensive care unit, and many spinal surgeons are unwilling to perform the study due to safety & resource implications. Of 625 patients currently reported in the literature, dynamic fluoroscopy has a sensitivity of 92.3% and specificity of 98.8%. Two cases of neurological deterioration during the study have been reported, including one complete quadriplegia.

CT Scan whole Cervical Spine

In recent years, the concept of full cervical spine CT for assessment of spinal injury has emerged. There are several studies that have demonstrated the robustness of the full CT scan, with sagittal and coronal reconstructions, for the exclusion of significant spinal injury. Widening, slippage or rotational abnormalities of the cervical vertebrae suggest soft tissue injury. An absence of such signs appears to exclude significant instability. Abnormal findings on the CT scan are evaluated by a spinal surgeon and additional modalities, such as MRI, can be employed. No study has missed a cervical spine injury, and no study has identified an injury on plain films that was not apparent on the CT scan.

Helical or multislice CT scanning from the Occiput to T1 is performed at 2-3mm collimation and 1.5mm pitch. Sagittal and coronal reconstructions are must be closely examined for indications of ligamentous instability. When whole cervical spine CT scanning is performed, the antero-posterior plain film becomes redundant.

Thoracic & Lumbar Spine Injury

References

Computed Tomography of Occiput - C3

Kirshenbaum KJ, Nadimpalli SR, Fantus R, et al: Unsuspected upper cervical spine fractures associated with significant head trauma: Role of CT. J Emerg Med 8:183-98, 1990

Schenarts PJ, Diaz J, Kaiser C et al 'Prospective comparison of admission computed tomographic scan and plain films of the upper cervical spine in trauma patients with altered mental status.' J Trauma. 2001 Oct;51(4):663-8

Incidence of Ligamentous Instability

Chiu WC, Haan JM, Cushing BM, Kramer ME, Scalea TM. Ligamentous injuries of the cervical spine in unreliable blunt trauma patients: incidence, evaluation, and outcome. J Trauma 2001 Mar;50(3):457-63;

Demetriades D, Charalambides K, Chahwan S et al 'Nonskeletal cervical spine injuries: epidemiology and diagnostic pitfalls' J Trauma. 2000 Apr;48(4):724-7

Magnetic Resonance Imaging

Albrecht RM, Kingsley D, Schermer CR et al Evaluation of cervical spine in intensive care patients following blunt trauma. World J Surg 2001 Aug;25(8):1089-96

Benzel EC, Hart BL, Ball PA et al. Magnetic resonance imaging for the evaluation of patients with occult cervical spine injury. J Neurosurg 85:824-9, 1996

Chee SG: Review of the role of magnetic resonance imaging in acute cervical spine injuries. Ann Acad Med 22:757-61, 1993

D'Alise MD, Benzel EC and Hart BL. Magnetic resonance imaging evaluation of the cervical spine in the comatose or obtunded trauma patient. J Neurosurg 91(1 Suppl): 54-59, 1999

Geck MJ, Yoo S, Wang JC. Assessment of cervical ligamentous injury in trauma patients using MRI. J Spinal Disord 2001 Oct;14(5):371-7

Goldberg AL, Rothfus WE, Deeb ZL, et al: The impact of magnetic resonance on the diagnostic evaluation of acute cervicothoracic spinal trauma. Skeletal Radiol 17:89-95, 1988

Katzberg RW, Benedetti PF, Drake CM, et al Acute cervical spine injuries: prospective MR imaging assessment at a level 1 trauma center. Radiology 1999 Oct;213(1):203-12

Silberstein M, Tress BM, Hennessy O: Prevertebral swelling in cervical spine injury: Identification of ligament injury with magnetic resonance imaging. Clin Radiol 46:318-23, 1992

Dynamic Fluoroscopy

Ajani AE, Cooper DJ, Scheinkestel CD et al. Optimal assessment of cervical spine trauma in critically ill patients: a prospective evaluation. Anaesth Intensive Care 26:487-91, 1998

Brooks RA, Willett KM. Evaluation of the Oxford protocol for total spinal clearance in the unconscious trauma patient. J Trauma 2001 May;50(5):862-7

Cox MW, McCarthy M, Lemmon G, Wenker J. Cervical spine instability: clearance using dynamic fluoroscopy. Curr Surg 2001 Jan;58(1):96-100 Cervical spine instability: clearance using dynamic fluoroscopy.

Croft AC; Krage JS; Pate D; Young DN Videofluoroscopy in cervical spine trauma: an interinterpreter reliability study. J Manipulative Physiol Ther, 1994 Jan, 17:1, 20-4

Davis JW, Kaups KL, Cunningham MA et al: Routine evaluation of the cervical spine in head-injured patients with dynamic fluoroscopy: a reappraisal. J Trauma 2001 Jun;50(6):1044-7

Davis JW, Parks SN, Detlefs CL, et al: Clearing the cervical spine in obtunded patients: The use of dynamic fluoroscopy. J Trauma 39:435-8, 1995

Hino H, Abumi K, Kanayama M, Kaneda K Dynamic motion analysis of normal and unstable cervical spines using cineradiography. An in vivo study. Spine 1999 Jan 15;24(2):163-8

Robert KQ 3rd, Ricciardi EJ, Harris BM. Occult ligamentous injury of the cervical spine. South Med J 2000 Oct;93(10):974-6

Sees DW, Rodriguez Cruz LR, Flaherty SF. The use of bedside fluoroscopy to evaluate the cervical spine in obtunded trauma patients. J Trauma 45:768-71, 1998

Computed Tomography of Complete Cervical Spine

Barba CA, Taggert J, Morgan AS et al 'A new cervical spine clearance protocol using computed tomography.' J Trauma. 2001 Oct;51(4):652-6

Berne JD, Velmahos GC, El-Tawil Q et al 'Value of complete cervical helical computed tomographic scanning in identifying cervical spine injury in the unevaluable blunt trauma patient with multiple injuries: a prospective study.' J Trauma. 1999 Nov;47(5):896-902

Daffner RH. 'Helical CT of the cervical spine for trauma patients: a time study.' AJR Am J Roentgenol. 2001 Sep;177(3):677-9

Keenan HT, Hollingshead MC, Chung CJ et al 'Using CT of the cervical spine for early evaluation of pediatric patients with head trauma.' AJR Am J Roentgenol. 2001 Dec;177(6):1405-9

 

Thoracic & Lumbar Spine Injury

trauma.org (7:4) April 2002