All posts by TheTraumaPro

VTE Prophylaxis Before Spine Surgery?

Many surgeons and surgical subspecialists are nervous about operating on people who are taking anticoagulants. This seems obvious when it involves patients on therapeutic anticoagulation. But it is much less clear when we are talking about lower prophylactic doses.

Spine surgeons are especially reluctant when they are operating around the spinal cord. Yet patients with spine injury are generally at the highest risk for developing venous thromboembolic (VTE) complications like deep venous thrombosis (DVT) or pulmonary embolism (PE). Is this concern warranted?

Surgeons at the Presley Trauma Center in Memphis examined this issue by performing a retrospective review of six years worth of patients who underwent spine stabilization surgery. They specifically looked at administration of any kind of preop prophylactic anticoagulant, and the most feared complications of bleeding complications and postop VTE.

Here are the factoids:

  • A total of 705 patients were reviewed, with roughly half receiving at least one preop prophylactic dose and the other half receiving none
  • There were 447 C-spine, 231 T-spine, and 132 L-spine operations, performed an average of 4 days after admission
  • Overall, bleeding complications occurred in 2.6% and VTE in 2.8%
  • Patients with VTE were more severely injured (ISS 27 vs 18)
  • Those who received at least half of their possible prophylactic doses had a significantly lower PE rate (0.4% vs 2.2%) but no significant difference in DVT or bleeding complications

Bottom line: So what to make of this? It’s a relatively small, retrospective study, and there is no power analysis. Furthermore, this hospital does not perform routine DVT screening, so that component of VTE may be underestimated, rendering the conclusions invalid.

However, the information on bleeding complications is more interesting, since this is much more reliably diagnosed using an eyeball check under the dressing. So maybe we (meaning our neurosurgeons and orthopedic spine surgeons) need to worry less about preop prophylactic VTE drugs. But we still need better research about whether any of this actually makes a dent in VTE and mortality from PE. To be continued.

Reference: Early chemoprophylaxis is associated with decreased venous thromboembolism risk without concomitant increase in intraspinal hematoma expansion after traumatic spinal cord injury. J Trauma 83(6):1108-1113, 2017.

A New Proposed Practice Guideline For Cervical Spine Clearance

In my last post, I reviewed a very recent prospective study on using CT scan alone for  cervical spine clearance in intoxicated patients. I believe that this is the final piece in the spine clearance puzzle to allow us to perform this task intelligently.

We’ve been accumulating more and more data that supports the use of CT scan in patients who fail clinical clearance. This failure can be due to the patient being obtunded or intoxicated, bearing a “distracting” injury, or being just plain uncooperative. Because of this, and our fear of missing a potentially devastating injury (typically because of rare anecdotal cases or urban legends), we have resorted to a significant degree of overkill. This has included, over the years, prolonged immobilization in a rigid collar, flexion/extension imaging (plain x-ray or fluoro), and MRI.

I’ve synthesized the available literature, and have drafted a simple, one sheet practice guideline for discussion. In order to use it, you must have the following:

  • A decent CT scanner – minimum 64 slice
  • A well-defined scan setup protocol – 3mm collimation, skull base to T2, 2-D reconstruction in sagittal and coronal planes (get a copy of our protocol below)
  • A skilled radiologist – neuroradiologist required

An image of the protocol can be found at the bottom of this post. I’m interested in your comments, and your comfort or discomfort with adopting something like this. Please leave comments here or on twitter.

Links: 

Reference: Cervical spine evaluation and clearance in the intoxicated patient: A prospective Western Trauma Association Multi-Institutional Trial and Survey. J Trauma 83(6):1032-1040, 2017.

It’s Time To Simplify Cervical Spine Clearance!

Cervical spine clearance is another one of those tasks that everyone seems to do their own way. Most trauma centers have an algorithm for clearance, or even two, like my center. But anytime different clinicians or centers do the same thing in different ways, it means we don’t really know what we’re doing. 

It basically means that the hard data is not there to dictate what we truly should do. So there are two alternatives:

  1. Wait for good data to become available. Unfortunately, this can take forever.
  2. Extrapolate from any existing data, and fill in the gaps with our clinical experience to come up with something that works and causes no harm.

The protocols in use at Regions Hospital are based on #2, and have been in place for over a decade. But now, we have a good example of #1 to work with.

Fortunately for us, cervical spine clearance has been evolving for decades. And as technology has improved, so has our ability to miss fewer and fewer “significant” injuries. A multi-center trial published this month provides one of the final puzzle pieces to help us settle upon a uniform cervical spine clearance guideline. It was a prospective look at intoxicated patients after blunt trauma, who can’t always participate in the process of clinical cervical spine clearance.

This three year study took place at 17 centers and specifically looked at the combination of clinical and radiographic clearance in alcohol and drug intoxicated patients. Over 10,000 patients participated in the study. There are some limitations, of course, when so many centers participate. But the pros massively outweigh the cons.

Here are the factoids:

  • The overall incidence of cervical spine injury was 10.6% (!)
  • 30% of patients were intoxicated (19% etoh, 6% drugs, 5% both (also !)
  • Intoxicated patients had a significantly lower incidence of cervical injury (8% vs 12%). (Don’t get any ideas about the old adage about being relaxed when they crash. This probably represents lower speeds involved.)
  • For intoxicated patients, sensitivity of CT scan was 94%, specificity was 99.5%, and the negative predictive value (NPV) was 99.5%
  • The NPV for clinically significant injuries in intoxicated patients was 99.9%, and no unstable injuries were missed by CT  (100% NPV) (!!)
  • When CT was negative, being intoxicated led to longer time in a collar (8 hrs vs 2 hrs)

Bottom line: Fear of clearing the cervical spine without a clinical exam, or in obtunded or intoxicated patients, is primarily due to old anecdotal reports. And much of it is not first-hand experience, but rumors of others’. What is finally becoming clear is that it is okay to clear based upon radiographic findings alone. 

Tomorrow, I’ll provide my version of a new, unified clearance protocol based on this work.

Reference: Cervical spine evaluation and clearance in the intoxicated patient: A prospective Western Trauma Association Multi-Institutional Trial and Survey. J Trauma 83(6):1032-1040, 2017.

Deer Hunting and Tree Stand Injuries

Deer hunting season is upon us again in Minnesota and Wisconsin, so it’s time to plan to do it safely. Although many people think that hunting injuries are mostly accidental gunshot wounds, that is not the case. The most common hunting injury in deer season is a fall from a tree stand.

Tree stands typically allow a hunter to perch 10 to 30 feet above the ground and wait for game to wander by. They are more frequently used in the South and Midwest, usually for deer hunting. A recent study by the Ohio State University Medical Center looked at hunting related injury patterns at two trauma centers.

Half of the patients with hunting-related injuries fell, and 92% of these were tree stand falls. Only 29% were gunshots. And unfortunately, alcohol increases the fall risk, so drink responsibly!

Most newer commercial tree stands are equipped with a safety harness. The problem is that many hunters do not use it. And don’t look for comparative statistics anytime soon. There are no national reporting standards. No matter how experienced you are, always clip in to avoid a nasty fall!

The image on top is a commercial tree stand. The image below is a do-it-yourself tree stand (not recommended). Remember: gravity always wins!