61108

Twist Drill Hole for Evacuation and/or Drainage of Subdural Hematoma

CPT code 61108 describes a neurosurgical procedure where a specialized twist drill is utilized to create a small opening in the skull to access the subdural space, specifically for the evacuation or drainage of a subdural hematoma. A subdural hematoma is a collection of blood that accumulates between the dura mater and the arachnoid mater, often resulting from traumatic injury or spontaneous rupture of bridging veins. This procedure is a minimally invasive alternative to more extensive surgeries like a craniotomy or even a traditional burr hole. Because the twist drill hole is significantly smaller than a burr hole, it is frequently performed at the bedside in emergency situations or in patients who are too unstable for general anesthesia or a trip to the operating room. During the procedure, the surgeon identifies the optimal entry point based on preoperative imaging, such as a non-contrast CT scan of the head. After local anesthesia is administered, a small skin incision is made, and the twist drill is used to manually or mechanically penetrate the outer and inner tables of the skull. Upon breaching the skull, the dura is punctured, allowing the pressurized blood (which may be acute, subacute, or liquefied chronic blood) to be evacuated. In many clinical scenarios, a drainage catheter is inserted through the hole into the subdural space and connected to a closed-suction system to facilitate ongoing drainage and prevent the re-accumulation of fluid over the following 24 to 72 hours. This intervention is vital for reducing intracranial pressure and reversing neurological deficits caused by mass effect or midline shift.

Clinical Indications

  • Acute subdural hematoma with significant mass effect or neurological deterioration
  • Chronic subdural hematoma causing symptomatic brain compression
  • Subacute subdural hematoma with evidence of increasing intracranial pressure
  • Midline shift identified on neuroimaging
  • Need for emergent decompression in patients unable to tolerate general anesthesia
  • Recurrent subdural hematoma following previous drainage

Procedure Steps

  1. Verify patient identity and confirm surgical site using recent CT or MRI imaging.
  2. Position the patient to optimize access to the skull over the thickest part of the hematoma.
  3. Perform sterile preparation and draping of the operative site.
  4. Administer local anesthetic (e.g., 1% lidocaine with epinephrine) to the scalp and periosteum.
  5. Make a small linear incision (approximately 1 cm) down to the bone.
  6. Utilize a twist drill bit with a depth guard to perforate the skull at a right angle or directed toward the collection.
  7. Carefully advance the drill until a 'give' is felt, indicating penetration of the inner table.
  8. Puncture the dura mater using a sharp instrument or the drill bit itself if necessary.
  9. Allow the subdural fluid to egress; irrigate the space if indicated for liquefied collections.
  10. Insert a subdural catheter or drain into the space if continuous drainage is required.
  11. Secure the drain with sutures and apply a sterile dressing.
  12. Connect the drain to a collection system and confirm flow.

Coding Guidelines

  • Do not report 61108 in conjunction with more extensive procedures like 61312 (Craniotomy for evacuation of hematoma) if performed at the same site during the same session.
  • Placement of a subdural drain or catheter is considered an integral part of 61108 and is not coded separately.
  • For bilateral procedures (e.g., draining hematomas on both the left and right sides), append modifier 50 to code 61108.
  • If the procedure is performed at the bedside rather than the operating room, it is still reported with 61108.
  • The use of radiological guidance (e.g., 77011 for CT guidance) is generally not reported separately unless specifically documented as meeting separate medical necessity criteria.
  • 61108 has a 90-day global period in the CMS fee schedule.

Associated ICD-10 Codes