Lumbar Puncture

Lumbar puncture (LP), also known as a spinal tap, is a widely used medical procedure with both diagnostic and therapeutic applications. This technique involves the collection of cerebrospinal fluid (CSF) from the subarachnoid space, achieved by inserting a needle between two lumbar vertebrae. Since its first reported use in 1898¹, lumbar puncture has been essential for the diagnosis and treatment of neurological and non-neurological diseases, particularly conditions such as spinal muscular atrophy (SMA).² Despite its utility, the procedure carries certain risks and complications, including post-lumbar puncture headache (PLPH), infection, and hematoma.

Indications for Lumbar Puncture

• The lumbar puncture procedure is used in a variety of clinical settings. The most common applications include:
  CSF analysis:
  • Inflammatory process: LP can aid in the diagnosis of meningitis, encephalitis, multiple sclerosis, and other conditions such as Lyme disease and neurological disorders.
  • Biomarker Discovery: Detection of disease-specific biomarkers in neurodegenerative diseases like Parkinson.
• Myelography: For imaging the spinal cord.
• Measurement of CSF pressure: Used to assess conditions such as idiopathic intracranial hypertension.
• Drug injection: Administration of medications like nusinersen in the treatment of SMA.

Lumbar Puncture Procedure

Technique

The lumbar puncture can be performed using either a landmark-guided or ultrasound-guided technique. The puncture is typically performed at the L4-L5 intervertebral space, with the patient in a sitting or lateral decubitus position.

• Landmark technique: This involves identifying surface landmarks such as the iliac crest to guide the needle placement.
• Ultrasound-guided technique: This approach is particularly useful in patients with complex anatomy. A curvilinear ultrasound probe (60mm, 5-2 Hz) helps identify the optimal puncture site.

Prior to the procedure, the puncture site is anesthetized with a local anesthetic, and a spinal needle, such as a atraumatic Sprotte or a traumatic Quincke needle, is inserted.
Once CSF flow is confirmed, it can be collected using a 10 ml syringe.^3,4

Special Cases: Lumbar Puncture for Nusinersen Administration

In SMA patients, lumbar puncture is used for the intrathecal administration of nusinersen, an antisense oligonucleotide and the first approved treatment for SMA. Patients are typically positioned laterally, and the procedure may be supported by pre-procedural imaging (CT or MRI) to guide the approach.²

Complications of Lumbar Puncture

Post-Lumbar Puncture Headache (PLPH)

PLPH is the most commonly reported complication, with an incidence ranging from 0.49% to 36% in different studies. It occurs due to CSF leakage at the puncture site, causing intracranial hypotension. PLPH is characterized by headache that worsens with standing and is relieved with lying down. The use of atraumatic needles, such as the Sprotte needle, has been shown to reduce the risk of PLPH.⁵

Intracranial Hematomas and Abscesses

Intracranial hematomas are a rare but serious complication. Hematomas may develop after both intentional and unintentional dural punctures. Symptoms include persistent headache, nausea, dizziness, and neurological deficits.
Treatment often involves surgical drainage, although conservative management is possible in some cases.
Abscesses and empyema are other rare but significant complications. These infections can occur after contamination of the spinal trays or infection from patient or practitioner flora.⁶

Meningitis

Meningitis, both bacterial and aseptic, is a potential complication of lumbar puncture. While rare, it may arise from contaminated instruments or pre-existing infections. Meningitis can affect both adults and children.⁷

Disc Joint Penetration

Accidental puncture of the intervertebral disc joint during the procedure can lead to discitis or disc degeneration, potentially causing degenerative lumbar diseases.⁸

Neonatal and Pediatric Complications

In neonates, LP complications include positive CSF cultures, respiratory distress, and skin burns due to chlorhexidine. Traumatic lumbar punctures (in which blood enters the CSF sample) occur in 35-46% of cases.⁹

Contraindications of Lumbar Puncture

Absolute Contraindications

• Intracranial hypertension: Performing a lumbar puncture in patients with elevated intracranial pressure can lead to brain herniation.
• Infection at the puncture site: To avoid the spread of infection to the central nervous system.
• Allergies to local anesthetics: If anesthesia is necessary for the procedure.
• Hypovolemia: This condition can exacerbate complications from CSF leakage.
   

Relative Contraindications

• Anticoagulant use/coagulopathy: Increases the risk of bleeding.
• Anatomic deformities: Conditions such as severe scoliosis or lumbar spine disease may hinder the procedure.
• Previous spinal surgery: Scar tissue or altered anatomy may complicate needle insertion.

Concluding Thoughts on Lumbar Puncture

Lumbar puncture is an essential diagnostic and therapeutic tool in medicine, offering insights into various neurological and systemic diseases through CSF analysis. It also provides a route for administering specific treatments, such as nusinersen for SMA. However, as with any invasive procedure, lumbar
puncture carries risks of complications, including PLPH, infection, and more serious outcomes like hematoma. Advances in needle technology and imaging techniques, such as ultrasound guidance, have helped to reduce the incidence of complications, making lumbar puncture a safer procedure overall. Nonetheless, careful consideration of contraindications and thorough patient monitoring remain critical to minimizing risks.

Studies:

¹Li J., Krishna R., et al. (2020). Ultrasound-Guided Neuraxial Anesthesia. Current Pain and Headache Reports, 24 (59).
²Veiga-Canuto D., Cifrian-Perez M., et al. (2020). Ultrasound-guided lumbar puncture for nusinersen administration in spinal muscular atrophy patients. European Journal of Neurology, 28: 676-680.
³Jiang L., Zhang F., et al. (2020). Could preprocedural ultrasound increase the first pass success rate of neuraxial anaesthesia in obstetrics? A systematic review and meta analysis of randomized controlled trials. Journal of Anaesthesia, 34: 434-444.
⁴Nobuhara C. K., Bullock W. M., et al. (2020). A Protocol to Reduce Self-Reported Pain Scores and Adverse Events Following Lumbar Punctures in Older Adults. J. Neurol., 267 (7): 2002-2006.
⁵Cognat E., Koehl B., et al. (2021). Preventing Post-Lumbar Puncture Headache. Annals of Emergency Medicine, 78 (3): 443-450.
⁶Bos E. M., van der Lee K., et al. (2021). Intracranial hematoma and abscess after neuraxial analgesia and anaesthesia: a review of the literature describing 297 cases. American Society of Regional Anesthesia & Pain Management, 46: 337-343.
⁷Ertas A., Gediz T., et al. (2021). Risk of intervertebral disc joint puncture during lumbar puncture. Clinical Neurology and Neurosurgery, 200 (106107).
8Hadzic A. (2017). Hadzic´s textbook of Regional Anesthesia and Acute Pain Management. McGraw-Hill Education, 2.
⁹Flett T., Athalye-Jape G., et. al. (2020). Spinal needle size and traumatic neonatal lumbar puncture: an observational study (neo-LP). European Journal of Pediatrics, 179:939-945.