Tag Archives: craniectomy

Is Decompressive Craniectomy Any Better Than Craniotomy?

Severe TBI consists of a primary injury to the brain, followed by swelling, vascular, and ischemic problems which may cause a secondary injury. Much of the critical care management of this injury involves avoiding or ameliorating secondary injury. This is typically accomplished via medical means first, and through surgical procedures when medical management is insufficient.

Two types of surgical decompression are currently practiced: craniotomy and evacuation of blood/clot, and decompressive craniectomy with removal of a bone flap. The latter can be performed prophylactically before severe swelling occurs, or therapeutically as a damage control procedure when ICP is refractory to all other measures.

There has been a decades-old debate as to whether craniectomy, which is a major undertaking with months of skull/bone flap management, is actually worthwhile. Most studies have examined the utility of damage control craniectomy for refractory ICP. The results have not really been convincing one way or the other.

But what about prophylactic decompressive craniectomy (DC) to avoid future ICP problems while the patient is in the ICU? The surgical group at the University of Arizona at Tucson performed a five year retrospective review of their experience. Using propensity score matching, they identified 99 severe TBI patients who underwent DC (33) or craniotomy only (CO, 66). A power analysis showed that this sample size should be sufficient to demonstrate a significant difference.

Here are the factoids:

  • Both groups were similar with respect to age, GCS, ISS, AIS-head, and type of bleed
  • 26% died and 63% were discharged to rehab or skilled nursing facility
  • When comparing DC to CO groups, there were no differences in mortality, discharge to skilled nursing facility, discharge GCS or Glasgow Outcome Scale
  • There were more complications in the DC group, including shunt insertion for hydrocephalus (9% vs 0%), and reoperation (12% vs 2%)
  • Rates of wound infection and ventriculitis were the same for both groups (0-3%)

Bottom line: Although the study is small, it supposedly had enough patients for identification of significant differences. And basically, it didn’t show a positive difference for prophylactic decompressive craniectomy. There is certainly some opportunity for selection bias by the neurosurgeons that cannot be controlled for by this retrospective design. But it is yet another piece of the decompressive craniectomy puzzle. 

Overall, the literature support for either prophylactic or damage control craniectomy is not very strong. If it were, we would have identified some real benefits by now. What we don’t know is if there are specific subgroups of severe TBI patients who might benefit from it. So if your center is not involved in a project to study this, you should probably ask your neurosurgeons to base their practice only on what we know about this procedure to date. 

Everything You Wanted To Know About: Cranial Bone Flaps

Patients with severe TBI frequently undergo surgical procedures to remove clot or decompress the brain. Most of the time, they undergo a craniotomy, in which a bone flap is raised temporarily and then replaced at the end of the procedure.

But in decompressive surgery, the bone flap cannot be replaced because doing so may increase intracranial pressure. What to do with it?

There are four options:

  1. The piece of bone can buried in the subcutaneous tissue of the abdominal wall. The advantage is that it can’t get lost. Cosmetically, it looks odd, but so does having a bone flap missing from the side of your head. And this technique can’t be used as easily if the patient has had prior abdominal surgery.

2. Some centers have buried the flap in the subgaleal tissues of the scalp on the opposite side of the skull. The few papers on this technique demonstrated a low infection rate. The advantage is that only one surgical field is necessary at the time the flap is replaced. However, the cosmetic disadvantage before the flap is replaced is much more pronounced.

3. Most commonly, the flap is frozen and “banked” for later replacement. There are reports of some mineral loss from the flap after replacement, and occasional infection. And occasionally the entire piece is misplaced. Another disadvantage is that if the patient moves away or presents to another hospital for flap replacement, the logistics of transferring a frozen piece of bone are very challenging.

4. Some centers just throw the bone flap away. This necessitates replacing it with some other material like metal or plastic. This tends to be more complicated and expensive, since the replacement needs to be sculpted to fit the existing gap.

So which flap management technique is best? Unfortunately, we don’t know yet, and probably never will. Your neurosurgeons will have their favorite technique, and that will ultimately be the option of choice.

Reference: Bone flap management in neurosurgery. Rev Neuroscience 17(2):133-137, 2009.

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.