Unlocking Common ED Procedures – Crackin’ the Cranium: A Review of Cranial Burr Hole Decompression

Authors: Edmund Hsu, MD (EM Resident Physician, Mt. Sinai St. Luke’s West) and Nicholas Buffin, MD (EM Resident Physician, Mt. Sinai St. Luke’s West) // Reviewed by: Anthony DeVivo, DO (Critical Care Fellow, Icahn School of Medicine-Mount Sinai Hospital); Alex Koyfman, MD (@EMHighAK); Brit Long, MD (@long_brit); Manpreet Singh, MD (@MPrizzleER)

Today’s Unlocking Common ED Procedures post looks at an uncommon but emergent procedure: the burr hole for cranial decompression.

Check out our new downloadable procedure card with QR code link to the article. Print them out and be ready to go over it with your learners!


Case:

A 53-year-old female with no significant past medical history presents to the Emergency Department (ED) with headache after syncope while on a treadmill.  She is transported to the ED after EMS finds her confused. Upon arrival to the ED, the patient is brought to the resuscitation bay where the blood pressure is 177/98 mmHg, and you begin your assessment of the patient. The patient is responsive and confused, repeating “my head” when questioned. A stat CT head is obtained, revealing a right temporal epidural hematoma with midline shift. You elevate the head of the bed and start IV antihypertensives. The patient becomes more somnolent and bradycardic. Her pupil on the right is 8 mm and unreactive and prior to CT was 3 mm and reactive. After intubation what are your next steps? What if there is no neurosurgery service at your hospital? Do you have additional tools at your disposal to decrease intracranial pressure?

Indications for emergent cranial decompression:1

1. CT-proven intracranial hematoma epidural/subdural (ICH) with midline shift

2. Previously verbal patients who deteriorate with anisocoria

3. Glasgow Coma Scale (GCS) score <8

4. No Neurosurgeon available in a reasonable time frame

The decision to drill through someone’s skull should not be made lightly, and so the indications for such an event must be clear. A key indication is that there should be no accessible neurosurgeon available to perform the procedure. In addition to being more adequately trained in the procedure, they will have access to tools that will not be boxed and ready in your trauma bay. Every effort should be made to discuss with a neurosurgeon about the patient and plan for procedure prior to intervention; however planning should not delay emergent intervention. A prospective survey of 81 patients found that the median transfer times for epidural hematomas and subdural hematomas were 5.25 hours and 6.0 hours.2 A prospective study of 21 patients indicated poor prognosis if the delay before procedure was greater than 70 minutes. The average time from presentation to trephination at the local emergency department was 55 minutes and to trephination at transfer hospital was 207 minutes. The study recommends that a burr hole decompression should occur in between 60 – 90min after the onset of anisocoria.3,4 Due to the urgency presented, it is important to know what resources are available to you at your institution, as well as the general mode and time to transfer to your nearest neuro-ICU. The other indications are that the patient has the following indications: was previously verbal with anisocoria and deteriorates, the GCS <8, and the CT shows an ICH with midline shift.1


The Procedure:

General Procedure:1,5

  • Create an environment that will facilitate ease of procedure, including positioning patient and ensuring easy access to equipment. This should include intubation if GCS is less than 8. Perform a time out to ensure that everyone involved is aware of the patient identity, the plan for the coming procedure, why the procedure is being performed, and the side on which the procedure will occur.
  • After intubation the patient should be appropriately sedated with amnestic and analgesic medications.
  • Prophylactic antibiotics covering gram positive organisms should be considered at this time. A prospective study found that the most common organism responsible for post-operative central nervous system infections was Staphylococcus. Of the patients who underwent cranial burr-hole surgery, the only independent risk factor for infection was the absence of prophylactic antibiotics.6
  • Confirm skull thickness on CT as seen below in figure 1. The drill (sometimes called the trephine) should be set with the guard at the appropriate depth (If unable to confirm depth on CT, set to 1 cm and then increase to 1.5 cm if needed).
  • Position patient in supination and elevate the shoulder ipsilateral to the ICH with a shoulder roll. This will allow easier access to the area of the skull that you are trying to access.
  • On a CT scan, confirm the location and mark the area so the burr hole is over the center of the ICH and discuss with neurosurgery for any adjustments based off the CT. See notes below for specifics on different landmarks (parietal, frontal, temporal, posterior).
  • The below instructions are for a temporal ICH (intracranial hematoma epidural/subdural), which is the most common ICH. If CT is unavailable, the temporal burr hole should be performed first on the side ipsilateral to the larger pupil and/or the side with trauma, since temporal lobe decompression is usually the most urgent priority in acute cerebral herniation.
  • A large area of the temporal region is shaved and prepared in a sterile manner with betadine/chlorhexidine and a local anesthetic injected subcutaneously using a 25G needle.
  • Make a 3-5 cm incision through the skin down to the periosteum. For a temporal ICH, this would be 2 cm superior and 2 cm anterior to the tragus of the ear.
  • Once this incision is made, use the mosquito forceps to move the periosteum to the side and allow the self-retaining retractor to be placed along the periosteum. When expanded, this should create a clear path directly down to the bone.
  • The drill can then be placed perpendicular to the bone. The guard should be set at the appropriate depth. Turn the crank slowly and smoothly, while continuing to apply pressure. To prevent the head from shifting under this pressure have an assistant brace the head. It is possible to run sterile saline onto the skull to both remove debris and to keep the friction heat to a minimum.
  • Once through, if the ICH was epidural you should see blood coming from the burr hole as seen below in figure 2. If the blood has clotted run some sterile saline over the area to softly break it up.
  • If required, it is possible to use a pediatric suction catheter (not displayed above) to remove the blood from the epidural space. In the temporal region the most likely source of bleeding is the middle meningeal artery, which can be clamped if observed.
  • If a subdural hematoma was noted on CT scan, use a sharp hook (not pictured) to elevate the dura, and use scissors to make a small incision.
  • If no blood is noted to extravasate, continue to work towards transferring the patient to more definitive care.
  • This procedure provides the patient with valuable time to be transferred for definitive care.
  • Remember that burr hole evacuation cannot correct the bleeding point. Therefore, the operating room at your site or transfer site must be always prepared for subsequent craniotomy following burr hole evacuation in the emergency room.
  • If there is no designated trephination tool available, an intraosseous needle may be a possible substitute. One case report discussed using a 25-mm EZ-IO IO needle and electric driver in discussion with an on-call neurosurgeon.7

 

This general procedure was adapted from reference 1 and 5, and discussion with our in-house neurosurgical consult.

 

Descriptions of the burr hole locations [see Figure 3]:

Temporal – 2 finger-breadths above and 2 finger-breadths forward of the auditory canal

Parietal – over parietal eminence

Frontal – 10 cm above eye in mid-pupillary line (about 3 cm from sagittal suture)

*Posterior fossa- 3 cm medial to the easily palpated mastoid eminence

A posterior cranial fossa burr hole may be considered. ICH is rare in the posterior fossa, comprising only 4 to 13% of acute EDH and 1% of acute SDH. The risk of surgical complications is even higher in this area; therefore, it should be pursued only as a last resort or if there is obvious injury only to this area.8


Tips, Tricks, and Considerations:

  1. Emergency department skull trephinations are commonly done in the temporal location 2 cm anterior and 2 cm superior to the tragus
  2. You can start at 1 cm depth if you didn’t measure the thickness on the CT and increase to 1.5 cm
  3. Shave a large area of the hair
  4. Do not trephinate into a skull fracture
  5. Attempt to discuss with a neurosurgeon for their expert opinion

Rapid Procedure Review:

  1. Confirm indication for trephination
  2. Discuss with neurosurgery
  3. Prepare the equipment and the patient
  4. Emergency department skull trephinations are typically performed in the temporal location but confirm on CT
  5. Measure the skull thickness on CT to set stopper depth
  6. Shave the hair in the area, sterilize and drape
  7. Anesthetize area
  8. Make a vertical skin incision down to the periosteum at a point that is 2 cm superior and 2 cm anterior to the tragus if temporal location.
  9. Blunt dissect down to the periosteum and then place retractor after reaching the periosteum
  10. Have an assistant hold the patient’s head firmly prior to and while drilling
  11. Apply the trephine with gentle, steady pressure until the skull is penetrated. The bone fragment may come out in the device or may need to be removed with forceps.
  12. Once the bone fragment is removed, the clot may extrude spontaneously or require gentle suction with a catheter.
  13. Clamp/ligate bleeding vessel if identified
  14. Prepare patient for transfer for definitive neurosurgical care.

References/Further Reading

  1. Wilson, M.H., Wise, D., Davies, G. et al. Emergency burr holes: “How to do it”. Scand J Trauma Resusc Emerg Med 20, 24 (2012) doi:10.1186/1757-7241-20-24
  2. Leach P, Childs C, Evans J, Johnston N, Protheroe R, King A: Transfer times for patients with extradural and subdural haematomas to neurosurgery in Greater Manchester. Br J Neurosurg. 2007, 21 (1): 11-15. 10.1080/02688690701210562.
  3. Smith SW, Clark M, Nelson J, et al. Emergency department skull trephination for epidural hematoma in patients who are awake but deteriorate rapidly. J Emerg Med. 2010 Sep;39(3):377-83.
  4. J.E. Cohen, A. Montero, Z.H. Israel. Prognosis and clinical relevance of anisocoria-craniotomy latency for epidural hematoma in comatose patients. J Trauma, 41 (1996), pp. 120-122
  5. Motohashi O, Kameyama M, Shimosegawa Y, Fujimori K, Sugai K, Onuma T: Single burr hole evacuation for traumatic acute subdural hematoma of the posterior fossa in the emergency room. J Neurotrauma. 2002, 19 (8): 993-998. 10.1089/089771502320317140.
  6. Prospective study evaluating post-operative central nervous system infections following cranial surgery. Ma YF, Wen L, Zhu Y. https://www.ncbi.nlm.nih.gov/pubmed/30282490; Br J Neurosurg. 2019 Feb;33(1):80-83.
  7. Durnford S, Bulstrode H, Durnford A, Chakraborty A, Tarmey NT. Temporising an extradural haematoma by intraosseous needle craniostomy in the District General Hospital by non-neurosurgical doctors – A case report. J Intensive Care Soc. 2018;19(1):76–79. doi:10.1177/1751143717734997
  8. Cranial burr holes and emergency craniotomy: review of indications and technique. Donovan DJ, Moquin RR, Ecklund JM. https://www.ncbi.nlm.nih.gov/pubmed/16532867 Mil Med. 2006;171:12–19.

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