Tag Archives: Cervical spine

Dysphagia and Cervical Spine Injury

Cervical spine injury presents a host of problems, but one of the least appreciated ones is dysphagia. Many clinicians don’t even think of it, but it is a relatively common problem, especially in the elderly. Swallowing difficulties may arise for several reasons:

  • Prevertebral soft tissue swelling may occur with high cervical spine injuries, leading to changes in the architecture of the posterior pharynx
  • Rigid cervical collars, such as the Miami J and Aspen, and halo vests all force the neck into a neutral position. Elderly patients may have a natural kyphosis, and this change in positioning may interfere with swallowing. Try extending your neck by about 30 degrees and see how much more difficult it is to swallow.
  • Patients with cervical fractures more commonly need a tracheostomy for ventilatory support and/or have a head injury, and these are well known culprits in dysphagia

A study in the Jan 2011 Journal of Trauma outlines the dysphagia problem seen with placement of a halo vest. They studied a series of 79 of their patients who were treated with a halo. A full 66% had problems with their swallowing evaluation. This problem was associated with a significantly longer ICU stay and a somewhat longer overall hospital stay.

Bottom line: Suspect dysphagia in all patients with cervical fractures, especially the elderly. Carry out a formal swallowing evaluation, and adjust the collar or halo if appropriate. 

Reference: Swallowing dysfunction in trauma patients with cervical spine fractures treated with halo-vest fixation. J Trauma 70(1):46-50, 2011.

What’s The Optimal Method For Inline Stabilization Of The C-Spine?

We’ve been pondering this question for nearly 30 years. In 1983, trauma surgeons at UCLA looked at a number of devices available at that time and tested them on normal volunteers. They measured neck motion to see which was “best." 

Here’s what they found:

  • Soft collar – In general, this decreased rotation by 8 degrees but insignificantly protected against flexion and extension. Basically, this keeps your neck warm and little else.
  • Hard collars – A variety of collars available in that era were tested. They all allowed about 8% flexion, 18% lateral movement, and 2% rotation. The Philadelphia collar allowed the least extension.
  • Sandbags and tape – Surprisingly, this was the best. It allowed no flexion and only a few percent movement in any other direction.

The Mayo clinic compared four specific hard collars in 2007 (Miami J, Miami J with Occian back, Aspen, Philadelphia). They found that the Miami J and Philadelphia collars reduced neck movement the best. The Miami J with or without the Occian back provided the best relief from pressure. The Aspen allowed more movement in all axes.

And finally, the halo vest is the gold standard. These tend to be used rarely and in very special circumstances.

Bottom line: 

  • For EMS: Rigid collar per your protocol is the standard. In a pinch you can use good old tape and sandbags with excellent results.
  • For physicians: The Miami J provides the most limitation of movement. If the collar will be needed for more than a short time, consider the well-padded Occian back Miami J (see below).

Miami J with Occian back

Related post:

References:

  • Efficacy of cervical spine immobilization methods. J Trauma 23(6):461-465, 1983.
  • Range-of-motion restriction and craniofacial tissue-interface pressure from four cervical collars. J Trauma 63(5):1120, 1126, 2007.

Trauma Mythbusters: Spinal Cord Injury From Airway Management

Airway management is one of the most anxiety provoking procedures performed by trauma professionals. The main fear is that the airway will be lost during attempts to secure it and patient demise will soon follow. Add some facial fractures, bleeding, and an “unfavorable body habitus”, and the average prehospital or ED provider is really on edge.

The next most common fear is that providing a definitive airway in a patient with a known (or even suspected) cervical spine injury could cause a catastrophic neurologic injury. This was first addressed back in 1989 (before the time of video laryngoscopy, and when flexible scopes were rarely available in the ED). The authors found no verifiable reports of such an injury in the entire English literature

Over the years, a few case reports have cropped up. As in so much of the medical literature, causality is hard to prove. The patient was normal before anesthesia, and afterwards they were not. Had to be the intubation, right?

Not so fast! Let’s break it down and look at what we do know. Biomechanical studies have shown that the manipulation that occurs in direct laryngoscopy isn’t as bad as it looks. Studies in uninjured models are enlightening (minimal movement with blade insertion, slight rotational movements with blade elevation, and a little more rotation during the intubation). Most of this (slight) movement occurs from occiput to C2, with little motion at all at C3 and below.

But that was on an uninjured model. What about ones that simulate an injured spine? Specifically an injury in the upper spine area that we know moves?

  • Cricoid pressure caused no appreciable changes in the spine
  • Chin lift and jaw thrust reduced space available for the cord (SAC) by 1 and 2.5mm, respectively, and caused an angulation of about 4-5 degrees
  • SAC narrowed by only 1.5mm, even with maximum flexion and extension
  • Oral and nasal intubation narrowed SAC by 1.6mm, and resulted in a maximum of 2.5 degrees of rotation
  • Video laryngoscopy results in about half of the rotational movement of direct laryngoscopy
But what about these sporadic reports of neurologic deficits after intubation? What is often neglected is that spinal blood flow and long-term neck positioning have a major impact on cord function. Even relatively mild malpositioning of the cervical spine for extended periods during an OR case have been documented. 

Bottom line: From a mechanical standpoint, even in unstable spine models, the maneuvers we use in preparation for intubation cause more movement of the spine than does the intubation procedure itself. The true number of spinal cord injuries actually (and provably) caused by intubation approaches zero. The literature suggests that video laryngoscopy results in less overall movement during intubation, but it doesn’t seem to have an impact on cord injury (you can’t get less than zero). 

References:

  • Spinal cord injury and direct laryngoscopy – the legend lives on. Br J Anesth 84(6):705-709.
  • Airway management in adults after cervical spine trauma. Anesthesiology 104(6):1293-1318, 2006.

How To: Flexion / Extension Views of the Cervical Spine

Clearance of the cervical spine can often be done using clinical criteria alone (see this video at http://youtu.be/NhjF9kDOcjE). If this is not possible, a combination of radiologic and clinical evaluation is usually carried out. 

In some cases, radiographic studies (usually CT) are normal, but there is pain on clinical exam. Our next step is to send the patient to xray for flexion and extension views. This exam is performed by removing the collar while the patient is sitting, so the thoracic and lumbar spines must be clear before ordering this. The patient then gently flexes and extends the neck to their limits of comfort. Images are then obtained at the limits of flexion and extension. The premise is that a normal, awake patient cannot and will not move their neck beyond their comfort level to the point where they could cause themselves neurologic injury. 

It is very important that you look at the images yourself. The radiologist may review the images and will report that “there is no evidence of subluxation at the limits of flexion and extension.” But the patient may have barely moved their neck!

The question is: how much flexion and extension do you need to have to clear the spine?

The answer is not easy to find, and is buried in literature from the 1980s and 90s. According to the EAST guidelines, the ideal amount is 30 degrees from neutral for both flexion and extension. This is not always achievable in elderly patients, so in those cases you must use your judgment. Talk to the patient to find out if they stopped moving their neck forward or backward due to pain, or because they just can’t move it that far.

Trouble signs to look for are:

  • Subluxation of more that 2mm at any level
  • Angulation of more than 11 degrees

Any abnormality should prompt a spine consult.

If the study is not abnormal but the amount of flexion and/or extension is not adequate, there are two options. First, just leave the collar in place and try again in a week or so and try again. This will allow any soft tissue injuries to get better and may allow a successful repeat study. The alternative is a more costly and less well-tolerated MRI.

References:

  1. EAST Practice Guidelines, Identifying Cervical Spine Injuries Following Trauma – Update (2000).
  2. Defining radiographic criteria for flexion-extension studies of the cervical spine. Robert Knopp et al. Ann Emerg Med. 2001 Jul;38(1):31-5.