Tag Archives: TBI

Subdural Hematomas and Hygromas Simplified

There’s a lot of confusion about subdural pathology after head trauma. All subdural collections are located under the dura, on the surface of the brain. In some way they involve or can involve the bridging veins, which are somewhat fragile and get more so with age.

Head trauma causes a subdural hematoma by tearing some of these bridging veins. Notice how thick the dura is and how delicate the bridging veins are in the image below.

When these veins tear, bleeding ensues which layers out over the surface of the brain in that area. If the bleeding does not stop, pressure builds and begins compressing and shifting the brain. A subdural hematoma is considered acute from time of injury until about 3 days later. During this time, it appears more dense than brain tissue.

After about 3-7 days, the clot begins to liquefy and becomes less dense on CT. Many hematomas are reabsorbed, but occasionally there is repeated bleeding from the bridging veins, or the hematoma draws fluid into itself due to the concentration gradient. It can enlarge and begin to cause new symptoms. During this period it is considered subacute.

It moves on to a more chronic stage over the ensuing weeks. The blood cells in it break down completely, and the fluid that is left is generally less dense than the brain underneath it. The image below shows a chronic subdural (arrows).

Hygromas are different, in that they are a collection of CSF and not blood. They are caused by a tear in the meninges and allow CSF to accumulate in the subdural space. This can be caused by head trauma as well, and is generally very slow to form. They can lead to slow neurologic deterioration, and are often found on head CT in patients with a history of falls, sometimes in the distant past. CT appearance is similar to a chronic subdural, but the density is the same as CSF, so it should have the same appearance as the fluid in the ventricle on CT.

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Return To Baseline After Concussion

Here’s another interesting paper that was presented at the Congress of Neurological Surgeons. There’s a lot of attention being focused on the incidence and management of concussion during sporting events. An international Concussion in Sport Group has been meeting for over 10 years, contemplating classification and management of this injury. They are considering using age to modify management of concussion in young athletes.

The authors looked at their own experience with 200 adolescent and young athletes. They stratified by age (younger = 13-16 year olds, older = 18-22 year olds), with 100 in each group. They matched them by number of previous concussions, and all underwent baseline and post-concussion ImPACT testing. They specifically looked at the number of days needed to return to baseline.

Interestingly, they identified significant differences in recovery time. And strangely enough, the older players did better than the younger ones. Overall, 90% returned to baseline within a month. But the younger players took 2-3 days longer to recover than the older ones. 

Bottom line: Looks like the Concussion in Sport Group is right on! Usually in trauma, older folks do worse than younger ones, so we tend to treat them more carefully. Not so in youngsters with concussions. Sports medicine physicians need to realize that the younger brain takes longer to recover, and they should err on the safe side and keep them out of the game longer. Objective testing to help predict return to play is extremely helpful.

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Reference: Sport-Related Concussion and Age: Number of Days to Neurocognitive Baseline. Oral presentation 145 – Congress of Neurological Surgeons 2012.

Operative Management Of TBI By Non-Neurosurgeons?

In the US, Level I and II trauma centers are required to have around the clock neurosurgical coverage. This becomes problematic, especially in more rural areas, because they are a scarce resource. This problem is not limited to the States, and other countries have learned how to deal with it in their own ways.

A recent paper from Austria and the Slovak Republic looked at how this issue is dealt with at some centers in central Europe, and the impact of having neurosurgical procedures performed by trauma surgeons. The researchers looked at various databases maintained by 10 tertiary care hospitals in a retrospective fashion. Patients were included if they had a GCS of 8 or less and they survived to ICU admission. Some centers had neurosurgeons available, while others had only trauma surgeons. Procedures were performed by the appropriate type of surgeon in each center.

A total of 743 patients were evaluated, and about 68% underwent a neurosurgical procedure while 6% had an ICP monitor inserted. About a quarter of these patients had other significant associated injuries and were excluded, since the authors were interested in measuring effects in TBI patients. This left 311 patients, of whom 61% were treated by neurosurgeons and the remainder by trauma surgeons.

Here are some of the interesting findings:

  • Prehospital airway was provided more frequently in the neurosurgical treatment group, which should potentially improve outcome
  • ED management time and time to OR was shorter in the neurosurgical treatment group, which should also potentially improve outcome
  • However, there was no difference in ICU survival, hospital survival, or long-term outcome!

Bottom line: This is an interesting but poorly constructed study. Don’t believe the results! Other researchers’ leftover databases were used, and some databases were excluded because “quality of care was not comparable” to other centers. This is the worst kind of selection bias! If you believe the results, then you would also have to believe that airway control and prompt operative management don’t really matter much. The paucity of neurosurgeons who are interested in trauma care is pervasive. However, we still need to look for solutions to this problem and they remain a very valuable member of the trauma team.

Reference: Outcome of patients with severe brain trauma who were treated either by neurosurgeons or by trauma surgeons. J Trauma 72(5):1263-1270, 2012.

Resident Work Hour Restrictions And Neurotrauma Complications

In the US, resident work hour restrictions went into effect in 2003, limiting the total number of hours worked per week and the number of consecutive hours without a break. The idea was that fatigue caused errors, which translates into patient complications or worse. Has this panned out? A number of previous publications have found no change; only a few have shown some benefit.

Researchers at Massachusetts General Hospital decided to apply the acid test to this theory. They selected a group of patients who were critically ill and challenging to care for, taken care of by a group of residents who had long work hours and were involved in long operative cases. The AHRQ National Inpatient Sampling Database was studied, comparing the outcomes of neurotrauma patients before and after work hours were initiated and in teaching and non-teaching centers.

A huge number of records were analyzed (40,000 before work hours restrictions, 67,000 after). The findings were intriguing:

  • The overall complication rate was the same before and after restrictions (1.2%)
  • The complication rate was 25% higher in teaching hospitals after restrictions took effect. It appears that this also correlated with higher hospital charges after restrictions.
  • Logistic regression was used to figure out whether this difference was from duty hours or just from the involvement of residents in care. Only duty hours were significant in this analysis.
  • If injury severity was included in the analysis, there were no differences in complications at all
  • There were no differences in mortality rates between any of the groups

Bottom line: Yes, fatigue is bad (see my previous posts below). But here is another (correlation) study that doesn’t bear out the original reasons to restrict resident work hours. In actuality, complications and charges increased after the restrictions went into effect. It is possible that the checks and balances in the system were effective in protecting patients from adverse outcomes. Could the changes in this study be due to staffing changes to meet the restrictions, which results in chronic understaffing which undercuts those checks and balances? Studies of this type can’t tell us that. And unfortunately, restrictions in the US are not going to go away, they’ll probably get worse.

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Reference: Higher Complications and No Improvement in Mortality in the ACGME Resident Duty-Hour Restriction Era: An Analysis of More Than 107?000 Neurosurgical Trauma Patients in the Nationwide Inpatient Sample Database. Neurosurgery 70(6):1369-1382, 2012.

Intracranial Hypertension In Pediatric Head Trauma

This 44 minute video is a good introduction to pediatric head trauma and intracranial hypertension. It covers physiology, diagnosis, as well as management using medications, position, decompression and hypothermia.

Presented at Multidisciplinary Trauma Conference at Regions Hospital on May 3, 2012 by Debbie Song MD, a pediatric neurosurgeon.