Lumbar punctures are painful! This is due to the needle puncturing the skin and deeper tissues and the pressure changes in the spinal canal. Some general recommendations to reduce pain during LP include:

Comfortable Positioning: The patient should be instructed to lie on their side with their knees drawn up to their chest and their chin tucked in, or sit upright with their head and upper back forward (often on a bedside table with a pillow). This helps to open up the spaces between the vertebrae and makes it easier for the needle to enter.

Distraction techniques: Deep breathing, focusing on a pleasant image or listening to music, child life specialists, and more can help the patient to relax and reduce the perception of pain.

Sedation: Midazolam, ketamine, fentanyl, or other agents may be used to for anxiolytics and sedation.

Local anesthesia: Lidocaine injected into the skin and deeper tissues at the site of the puncture can numb the tract and reduce pain. It has also been shown to increase the likelihood of success.

What about topical anesthetics? Can a topical cream or gel containing lidocaine or prilocaine be applied to the skin at the site of the puncture before the procedure to numb the area and reduce pain? And what about the J-Tip, a device that uses pressurized gas to send medication into the subcutaneous portion of the skin – deeper than topical anesthetics? The topical creams take up to 40-45 minutes to absorb completely and generally penetrate the outer two to three millimeters of skin most reliably. Injectable lidocaine, when done well, is reliable – but it can take years to master the ideal technique that doesn’t create a giant mound of subcutaneous lidocaine that can impact needle entry and landmarks. Is there evidence for the J-Tip? Should we be using it for LPs instead of injecting? There is inconclusive evidence that it’s better than placebo for IVs too – it may help… (see Auerbach, 2009). Let’s take a look at a couple of studies.

Needle-free jet injection of lidocaine for local anesthesia during lumbar puncture: a randomized controlled trial
Ferayorni et al.
Pediatr Emerg Care

This randomized, double-blinded, placebo-controlled trial in infants 0-3 months old getting an LP, younger than 3 months, presenting to the ED meeting clinical criteria for LP. All patients were administered the J-Tip and were then randomized to either treatment with 1% buffered lidocaine or an equivalent amount of sterile normal saline before LP. Vital signs, facial expressions, and crying times were recorded. These were used by two independent reviewers to determine Neonatal Facial Coding System with pain scores. The study included 55 patients and the authors noted that mean pain scores at the time of needle insertion were 4.1 (1.3) for the lidocaine group and 4.8 (0.5) for the saline group (P = 0.01). Length of cry was also shorter for those in the lidocaine group (38.5 versus 48.8 seconds (P = 0.04)). Agreement – κ – was 0.76 between 2 independent reviewers.

The authors conclude that J-Tip reduced crying time and facial pain scores with a decent kappa (agreement). The sample size was all in this single site, and J-Tip was not used in direct comparison to injectable.

A Randomized Double Blind Trial of Needle-free Injected Lidocaine Versus Topical Anesthesia for Infant Lumbar Puncture
Caltagirone et al.
Acad Emerg Med, 2017

This was a single-center (one academic Pediatric Emergency Department) randomized double-blind trial of J-Tip versus EMLA – topical anesthetic (TA) cream for pain relief in 66 infant LPs. Patients got randomized to J-Tip syringe containing 1% lidocaine and a placebo TA cream or J-Tip syringe containing saline and TA. The primary outcome was the difference between the Neonatal Faces Coding Scale (NFCS) before the procedure and during LP needle insertion. Secondary outcomes included changes in heart rate (HR) and NFCS throughout the procedure, difficulty with LP, number of LP attempts, provider impression of pain control, additional use of lidocaine, skin changes at LP site, and LP success.

Ultimately after excluding some for age, the study enrolled 32 to J-Tip, 34 to EMLA. They saw no difference detected in NFCS between the two treatment groups before the procedure and during needle insertion for the LP (p = 0.58, p = 0.37). Neither HR nor NCFS differed, and perception of pain by provider, and need for additional lidocaine were similar. Interestingly the J-Tip group were twice as likely to have a successful LP regardless of level of provider experience (level of training, prior LP experience) versus those in the TA group (relative risk = 2.0; 95% confidence interval = 1.01-3.93; p = 0.04).

Overall there was some pain relief, but there was no comparison to injectable – the long taught gold standard. Also, I don’t feel you can actually conclude that J-Tip makes you more likely to be successful if you are less experienced. They concluded that the depth of anesthesia from J-Tip was responsible for this. Their convenience sample size was small, and the J-Tip group had 3 APPs vs none and 4 attending vs 1 in the J-Tip vs TA group. We know that trainees don’t get many LPs these days and there’s too much variability in their population.

Conclusions

OK, so that’s not a lot of evidence. I therefore cannot conclude that J-Tip is anything other than an adjunct to the proper injection lidocaine before an LP. There is no direct comparison of J-Tip versus injecting lidocaine into the lumbar space. Furthermore, I have seen so many LPs performed without local anesthesia over the past several years in infants. Why? Without adequate anesthesia we are causing pain. Take the time to learn how to inject lidocaine correctly. It will not “ruin your landmarks.” If you are in a position to impact training for fellows, residents, and students advocate that injectable lidocaine be taught in line with the LP technique. And if you are in a position to try J-Tip before injecting lidocaine go ahead – it might help.

Bottom Line: The evidence does not show that J-Tip can replace injected lidocaine for local anesthesia during infant lumbar punctures

References

Caltagirone R, Raghavan VR, Adelgais K, Roosevelt GE. A Randomized Double Blind Trial of Needle-free Injected Lidocaine Versus Topical Anesthesia for Infant Lumbar Puncture. Acad Emerg Med. 2018 Mar;25(3):310-316. doi: 10.1111/acem.13351. Epub 2017 Dec 26. PMID: 29160002.

Ferayorni A, Yniguez R, Bryson M, Bulloch B. Needle-free jet injection of lidocaine for local anesthesia during lumbar puncture: a randomized controlled trial. Pediatr Emerg Care. 2012 Jul;28(7):687-90. doi: 10.1097/PEC.0b013e31825d210b. PMID: 22743744.

Auerbach M, Tunik M, Mojica M. A randomized, double-blind controlled study of jet lidocaine compared to jet placebo for pain relief in children undergoing needle insertion in the emergency department. Acad Emerg Med. 2009 May;16(5):388-93. doi: 10.1111/j.1553-2712.2009.00401.x. Epub 2009 Apr 15. PMID: 19388923.