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Advantages of ultrasound assisted lumbar puncture : new evidences

Three Part Question

In [obese and non-obese adults patients who need a lumbar puncture], should [ultrasound] be [used to localize the right space and improve first attempt success and reduce rate of traumatic tap]?

Clinical Scenario

While working the night shift, a patient is admitted for thunderclap headache 12 hours ago. After a negative head CT, you decide to do a lumbar puncture to rule out subarachnoid haemorrhage. You specifically need a non-traumatic LP and you wonder if localizing the right lumbar space with an ultrasound would reduce the rate of traumatic LP.

Search Strategy

Pubmed via medline was searched, details are as follows :

Reseach strategy: ((((((("Spinal Puncture"[Mesh]) OR spinal puncture*) OR lumbar puncture*) OR spinal tap*) OR lumbar tap*) OR LP)) AND (((((((((((((ultrasonography) OR medical sonography) OR ultrasonic imaging) OR echography) OR ultrasonic diagnos*) OR ultrasound diagnos*) OR ultrasound-assisted) OR echo-guided) OR POCUS) OR Point of care ultrasound) OR "Ultrasonography [Mesh])) OR U/S) = 506 results

Embase was searched, details are as follows :
('lumbar puncture'/exp OR "lumbar puncture" OR "spinal tap" OR "lumbar tap" OR "LP") AND ('ultrasound'/exp OR 'ultrasound' OR 'ultrasonography' OR 'echography' OR 'ultrasonic' OR 'pocus' OR 'point of care ultrasound' OR 'u/s' OR 'echo-guided')
References :
After reading references to relevant articles, 1 was found relevant :

One bestbet was done in 2007 with a neutral conclusion but many articles was found after 2007 and an update of the literature was considered necessary. :

4 trial were found on the subject but 2 are still recruiting, 1 was suspended, 1 the status was unknown.

After titles reading and duplicate eliminated : 34 results
After abstract/article reading : 9 articles

Search Outcome

After reading all 9 articles and evaluating the best evidence available a total of 4 relevant papers were considered in this review.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Peterson et al.
Adult ongoing LP for any clinical indication. In an emergency department (ED) setting. Randomization to the US group or the palpation landmarks group (PL). The US group: the right space was priory localized with the standard US procedure then the usual LP procedure. Prospective randomized controlled trialNumber of needle reinsertionNo significant difference (3 in the US group vs 5 in the PL group)The major weakness of this study is the training time of operator. An independent investigator trained them at the time of enrolment immediately prior to do the procedure. This would underestimate the results. No blinding. Convenience sample.
Success of LP (return of a non traumatic CSF)No significant difference (78% in the US group vs 76% in the PL group)
Pain measured on a VASNo significant difference (1.1 in the US group vs 3.0 in the PL group
Patient satisfaction (5 point likert scale)No significant difference (5 vs 5)
Median time of procedureNo significant difference (1.6 min in the US group vs 2.0 min in the PL group)
Mofidi et al.
Adults >18 years old <60, who needed an LP. Exclusion: cerebral lesion, local infection, pregnant women, coagulopathy, previous spinal surgery. In an emergency department setting. Patients were randomized to PL group or to US group.Prospective randomized clinical trialNumber of attemptsReduced number of attemps (1 in the US group vs 2 in the PL group, p=-0.047)No blinding of patients nor LP operator. This could overestimate the results.
Number of traumatic LPReduced number of traumatic tap (5 in the US group vs 18 in the PL group, p=0.024)
Pain score with a numerical 0 to 10 scaleIn the US guided LP, the pain score was significantly lower (4.4 vs 7.4).
Procedure timeTime (minutes) was significantly lower in the US group 3.3 vs 6.4 min
Shaikh et al.
Inclusion criteria for randomized control trial: - Randomization - Comparing US marking vs palpation procedure Reported at least one primary outcomes, Clinical trial, observation study and diagnostic studies were included. 14 trials were included, 5 for lumbar puncture, 674 patients in the US group and 660 in the PL group.Systematic review and meta-analysisFailed procedureReduced failed procedure, 6 in the US group vs 44 in the PL group (RR 0,21 [CI 95% 0.10-0.43]), NNT 16 to reduce one failureSearch strategy seems to be not enough sensible; the grey literature was not searched. 7 studies were done in an anaesthesia settings.
Traumatic procedureReduced traumatic procedure (RR 0.27 [CI 95% 0.11-0.67])
Number of needle reinsertionReduced number of reinsertion needle by a mean of -0.44 (-0.64 to -0.24)
Number of needle redirectionReduced number of redirection by a mean of -1.00 per procedure (-1.24 to -0.75, p<0.001)
Time of the procedureTime of the procedure could not be evaluated due to heterogeneity.
Nomura et al.
Adults >18 years old, who needed a LP; In an (ED) setting. All patients had a prior ultrasound to localize the right space and marked with an ultraviolet (UV) ink in a separate room, the LP operator then localized the right space by placing an UV ink by palpation landmarks. Randomization occurred after. A different investigator showed the mark to use based on the randomization results to the LP operator who was blinded to the origin of the mark.Randomized controlled double-blind studyNumber of attemptsNo significant difference in number of attempts (2 vs 2)Subgroup analysis very interesting but probably lacks power due to a small sample size. For the US procedure, the localization of the right angle was not included in the procedure.
Presence of a traumatic tapNo significant difference (RR=1.04 [CI 95% 0.83-1.31])
Success or failure of procedureIncreased success rate for US (RR 1.32 [CI 95% 1.01-1.72]), 1 failed in the US and 6 in the PL procedure
Length of operationNo significant difference (15 min in the US group vs 10.5 in the PL group)
Evaluation of the procedure (ease by the LP operator on a 10 cm VAS scale)No significant difference (3 in the US group vs 5.2 in the PL group)
Subgroup analysis for obese patients with a BMI >30Ease of procedure significantly better (2.7 cm for US vs 6.9 cm for PL), Others results had no significant difference but a trend toward US procedure


This review showed that with an appropriate training (which could be very brief because the technique is very easy to learn), ultrasound-assisted LP results in a better success rate. An extensive literature is available concerning paediatric populations, which showed a significant advantage to use the ultrasound (USS) prior to LP. Because doing LPs in paediatrics patients is relatively simple with the standard palpation landmark technique, doing a review about adult patients seemed more relevant, especially with obese patients. Except for the first study, this review was well designed and was done in emergency settings, which facilitate external validation. An interesting result is the median time of procedure. We could think that ultrasound-assisted procedure would require more time, but in fact, with better success rate and reduced needle reinsertion, the procedure takes less time or equal amount of time. This is a very important result to consider for emergency physicians. Finally, the USS training usually includes the evaluation of the right angulation of the needle for the procedure. None of these studies used this important technique. This would probably change the results in favour of USS. Future research on this subject, specifically enrolling obese adults as an inclusion criteria, and a study of cost-effectiveness, would be very interesting.

Editor Comment

BMI, body mass index; CSF, cerebrospinal fluid; LP, lumbar tap; NNT, number needed to treat; PL, palpation landmark; RCT, randomised controlled trial; RR, relative risk; USS, ultrasound; VAS, visual analogue scale.

Clinical Bottom Line

Using ultrasound-assisted landmarks prior to LP procedure improves success rate and reduces number of attempts and traumatic tap.


  1. Peterson MA , Pisupati D , Heyming TW , et al . Ultraound for routine lumbar puncture. Acad Emerg Med 2014;21:130–6.
  2. Mofidi M , Mohammadi M , Saidi H , et al . Ultrasound guided lumbar puncture in emergency department: time saving and less complications. J Res Med Sci 2013; 18: 303–7
  3. Shaikh F , Brzezinski J , Alexander S , et al . Ultrasound imaging for lumbar punctures and epidural catheterisations: systematic review and meta-analysis. BMJ 2013;346:f1720
  4. Nomura JT, Leech SJ, Shenbagamurthi S et al. A randomized controlled trial of ultrasound-assisted lumbar puncture. J Ultrasound Med 2007;26:1341–8.