The aim of the study is to assess the influence of ultrasound examination of the lumbar spinal canal on the effectiveness of lumbar puncture. An open-label, randomized interventional study.

Lumbar puncture is a common procedure performed in pediatric departments. The most common purpose of the examination in the pediatric patient population is to exclude infectious diseases of the central nervous system: meningitis and encephalitis. Risk factors for traumatic or unsuccessful puncture include, among others: patient age less than 3 months, difficulty in identifying anatomical structures by palpation, lack of local anesthesia, lack of experience of the person performing the procedure, and patient movement during puncture. The use of spinal canal ultrasonography before performing lumbar puncture brings promising benefits. Ultrasound imaging can be helpful in visualizing key anatomical structures within the spinal canal and increasing the certainty of correct performance of the procedure, especially in inexperienced physicians.

The study objective is to assess the effect of ultrasound imaging of the lumbar spinal canal on the effectiveness of lumbar puncture.

We plan to include every child <18 years old with an indication for lumbar puncture to the one of the two groups (ultrasound group and standard group)

Before the procedure, doctors performing the lumbar puncture in both groups will complete a questionnaire regarding their previous experience In the USG group, before performing the lumbar puncture, one of the two researchers will perform a bedside ultrasound examination of the lumbar spinal canal.

The ultrasound examination will be performed using a Lumify linear probe (frequency range 4-12 MHz). In the longitudinal projection, the doctor will assess the sites of the spinal cord endings by marking them with a sterile marker - a horizontal line on the patient's back. In the same projection, the doctor will designate a safe and optimal site (the greatest width of the dural sac) for performing a lumbar puncture by marking it with a sterile marker. Additionally, in the longitudinal projection, the researcher will measure the depth from the skin surface to the dura mater. Then, in the transverse projection, the doctor will confirm the absence of the spinal cord at the planned puncture site and the optimal amount of cerebrospinal fluid in the selected space. This information will be passed on to the operator, who will ultimately decide on the location of the lumbar puncture.

In patients in the control group, the lumbar puncture will be performed by palpation, without additional interventions. The position of the patient in both groups will depend on the preferences of the physician performing the puncture. The procedure time will be measured from the moment the needle pierces the skin until the moment of obtaining cerebrospinal fluid or removing the needle if the fluid is not obtained. In the research group, the time of the ultrasound examination will be additionally measured.

Inclusion Criteria:

• children <18 years of age
• patients who are scheduled to undergo lumbar puncture
• consent of legal guardian

Exclusion Criteria:

• infection of skin and tissues in the area of planned puncture
• developmental defects of the spine and spinal cord
• lack of consent of legal guardian
• contraindications to lumbar puncture

open-label study