ACEP ID:

Pediatric Emergency Medicine

Pearls & Pitfalls - How to Increase Your Success with Infant Spinal Taps

Larry Mellick, MD, MS, FAAP, FACEP
Professor of Emergency Medicine and Pediatrics
Medical College of Georgia

Pearl: Infant spinal taps will be more successful if one uses lidocaine for anesthesia and if one advances the needle without the stylet after penetrating the dermis and epidermis.

Discussion:

The Case for Local Anesthesia: It is common practice not to use lidocaine local anesthesia for spinal taps in infants. The opinion against anesthesia is pretty strong by pediatric residents and faculty. Only 9 of 198 (4.5%) patients who received a spinal tap in one pediatric emergency department of an academic medical center received local anesthetic. 1 A study by Breakey et al. was a survey of 374 pediatric and emergency medicine residents. 2 Pediatric residents (57%) reported much more frequently not using local anesthetic when performing spinal taps as compared to the emergency medicine residents (1%).2 Another study by Baxter et al. demonstrated that two-thirds of academic pediatric ED physicians do not use analgesia routinely for neonatal lumbar punctures. 3

But what does the evidence show? In 1993, Pinheiro et al. published an article that demonstrated a reduction in the infant's "struggling motion score" after lidocaine anesthesia was applied. 4 Despite the decreased motion noted in this study, there were no differences noted in the number of attempts per lumbar puncture, rate of lumbar puncture failure, or the number of traumatic lumbar punctures. 4 However, subsequent studies have indicated otherwise. In 2006, Baxter et al. found that advancement of the spinal needle with the stylet in place and lack of local anesthetic use were associated with traumatic or unsuccessful lumbar punctures. 5 Nigrovic et al. also analyzed the risk factors for traumatic or unsuccessful lumbar punctures in children and found, among other things, that lack of local anesthetic use was associated more often with failure. 6 In other words, the evidence is overwhelming that the infant struggles less and the success rate is higher when one uses local anesthesia. Despite the evidence to the contrary, the strength of resistance to using a little analgesia for infants is an interesting phenomenon.

Removing the Stylet: Another trick to improve the success rate and reduce the number of traumatic spinal taps is to remove the spinal needle's stylet before advancing the needle but after the needle has passed through the epidermis and dermis. Most clinicians are aware that lumbar punctures without a needle and a stylet are contraindicated, but they may not know why. During the era when practitioners used only butterfly needles or needles without stylets, it became clear that some of these children were developing epidermoid tumors. 7,8,9,10 On the other hand, while it has not been studied completely, early stylet removal is considered less risky for the development of an epidermoid tumor. In that light, it is recommended that the stylet be removed only after the needle has gone completely through the epidermis. Nevertheless, several studies have demonstrated that advancing the needle with the stylet removed (after passing through the skin) is associated with greater procedural success and fewer traumatic lumbar punctures. 5,6

Figure 1.
 stylet

References:

  1. Breakey VR, Pirie J, Goldman RD. Pediatric and emergency medicine residents' attitudes and practices for analgesia and sedation during lumbar puncture in pediatric patients. Pediatrics 2007;119:e631-6.
  2. Baxter AL, Welch JC, Burke BL, et al. Pain, position, and stylet styles: infant lumbar puncture practices of pediatric emergency attending physicians. Pediatr Emerg Care 2004;20:816-20.
  3. Pinheiro JM, Furdon S, Ochoa LF. Role of local anesthesia during lumbar puncture in neonates. Pediatrics 1993;91:379-82.
  4. Baxter AL, Fisher RG, Burke BL, et al. Local anesthetic and stylet styles: factors associated with resident lumbar puncture success. Pediatrics 2006;117:876-81
  5. Nigrovic LE, Kuppermann N, Neuman MI. Risk factors for traumatic or unsuccessful lumbar punctures in children. Ann Emerg Med 2007;49:762-71.
  6. Batnitzky S, Keucher TR, Mealey J, et al. Iatrogenic intraspinal epidermoid tumors. JAMA 1977;237:148-150.
  7. McDonald JV, Klump TE. Epidermoid spinal cord tumors caused by lumbar puncture. Arch Neurol 1986;43:936-939.
  8. Shaywitz BA. Epidermoid spinal cord tumors and previous lumbar punctures. J Pediatr 1972;80:638-640.
  9. Lumbar punctures and epidermoid tumors [editorial]. Lancet 1977;1:635.

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