Indication
- The sensitivity of lumbar puncture for leptomeningeal disease is about 45–55% after one puncture and 80–90% after two punctures → three lumbar punctures with negative findings before performing a lateral C1–C2 puncture for this indication.
Indication | Comments |
CSF collection | Cannot obtain safe lumbar access; CSF must be sampled above a spinal block or there is a possibility that a block is complete; lumbar puncture findings are negative for suspected intracranial or cervical leptomeningeal disease |
Myelography | Cannot obtain safe lumbar access; must delineate superior level of spinal block or there is a possibility that a block is complete |
Reasons for unsuccessful or unsafe lumbar puncture | Severe lumbar stenosis; severe degenerative or postsurgical changes; infection in lumbar region; congenital anomaly such as low conus or tethered cord; history of arachnoiditis with adhesions; inability to assume prone or lateral decubitus position |
Contraindication
- Absolute contraindications
- Chiari malformation,
- Cervical stenosis at C1–C2
- Evidence of herniation,
- Uncorrectable coagulopathy leading to an increased risk of bleeding,
- Coag should be stopped 1 week prior to procedure
- Platelet >50
- INR <1.4
- Known vertebral or posterior inferior cerebellar artery variant with vessel crossing the posterior spinal canal at C1–C2
- Prior MRI or CT angiogram, the vertebral and posterior inferior cerebellar arteries should be identified to ensure that there is no variant anatomy or vessel crossing the expected puncture location
- Obs(x) hydrocephalus
- Relative contraindications
- Uncooperative patient, who may require sedation or GA
- Low-lying cerebellar tonsils.
- Lowlying cerebellar tonsils increase the risk of tonsillar puncture and may cause altered CSF flow around the foramen magnum
- Contrast allergy
- Does the patient need to premedicated with steroids
Procedure
- Positioning
- Can be
- Prone
- Supine
- Lateral decubitus.
- Patient's neck is placed in a neutral position or slight hyperextension to increases the width of the dorsal subarachnoid space at C1–C2
- Entry point
- About 1 cm inferior and 1 cm posterior to the mastoid process.
- Using fluoroscopy, the puncture site is about 2–5 mm anterior to the spinolaminar line, posterior to the recently described C1 posterior arch flare point [50] and about 5 mm inferior to the posterior arch of C1
- Kelly clamp placed over posterior spinal canal at C1–C2 at intended puncture site (arrow). Note that tip of Kelly clamp is anterior to spinolaminar line (dashed line) at anterior border of posterior one-third of spinal canal, which is most anterior location that is acceptable for safe puncture.
- Before marking the puncture site, care should be taken to ensure that the image is a true lateral projection
- V3 segment of vertebral artery (red arrows)
- Ideal needle target (box) between
- Posterior arch of C1 (black arrowhead)
- Posterior arch of C2 (white arrowhead).
- Needle target is just anterior to spinolaminar line (dashed line) and inferior and posterior to mastoid process (white arrow).
- Lateral cervical spine radiograph shows ideal puncture site target location (box) just anterior to spinolaminar line (dashed white line).
- Notice alignment of inferior endplate of C2 and superior and inferior endplates of C3 (dashed black lines) as well as superimposed bilateral mastoid processes (arrow) and posterior C2 and C3 vertebral bodies (arrowheads) signifying true lateral radiograph.
- Fluoroscopic image shows findings characteristic of true lateral image, including superimposed mastoid processes (black arrow) and sharp endplates (dashed black lines) and posterior vertebral bodies (white arrowheads) at C2 and C3.
- Needle is angled anteriorly (white arrows) though needle tip remains posterior to C1 posterior arch flare point (black arrowhead) within posterior one-third of spinal canal.
- Notice that needle is just anterior to spinolaminar line (dashed white line).
- Anteroposterior fluoroscopic image shows needle tip (white arrow) within few millimeters of medial border of lateral mass of C1 (black arrow).
- CSF was obtained before needle reached midline.
Skin marking location
Anteroposterior fluoroscopic image shows needle tip (white arrow) past midline and almost at medial border of opposite lateral mass (black arrow) before CSF return. Dural tenting is to be expected, and at times needle must be advanced past midline before CSF return.
Made with Bullet