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Three Part Question

In [patients requiring lumbar puncture (LP)], is [ultrasonography assisted LP better than landmark technique] for [increasing chances of successful specimen collection]?

Clinical Scenario

A patient presents to the emergency department with fever, headache, and neck stiffness. You feel a lumbar puncture is a neccessary part of the patients work up; can bedside ultrasonography assist in specimen collection?

Search Strategy

Medline 1966-05/07 using the OVID interface, Cochrane Library (2007), PubMed clinical queries.
[(exp ultrsonography OR ultrasound.mp) AND (exp lumbar puncture OR lumbar puncture.mp)]. LIMIT to human AND English

Search Outcome

53 papers found of which only 3 papers were relevant

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Ferre, R. et al. 2007 USA	76 patients were enrolled after exclusion criteria. A convenience sample of emergency department patients were used at an academic referral center with an emergency medicine residency training program	prospective, observational trial	Two EPs sought to identify relevant anatomy in emergency patients. Visualization time for 5 anatomical structures (spinous processes or laminae, ligamentum flavum, dura mater, epidural space,subarachnoid space), body mass index, and perception of landmark palpation difficulty were recorded.	Soft tissue and bony anatomical structures were identified inSoft tissue and bony anatomical structures were identified in all subjects. Mean body mass index was 31.4 F 9.8 (95% confidence interval, 29.1-33.6). High-quality images were obtained in less than 1 minute in 153 (87.9%) scans and in less than 5 minutes in 174 (100%) scans. Mean acquisition time was 57.19 seconds; SD, 68.14 seconds; range, 10 to 300 seconds.	Data were obtained by 2 EPs who were working independently. There was no third party to check or verify data. Population was a convenience sample, not actual adults undergoing LP.
Stiffler, K. et al 2007 USA	The study enrolled a convenience sample of eligible patients at an ED. 62 patients were enrolled after excluion criteria.	prospective cross-sectional study	calculated the BMIs of eligible patients and then categorized them as normal (BMI V24.9), overweight (BMI 24.9-30), or obese (BMI z30). We recorded the difficulty in palpating traditional LP landmarks. Identification and measurement of the spatial relationships of the sacrum; spinous processes of lumbar vertebrae L3, L4,and L5; ligamentum flavum; and the spinal canal by US was attempted.	Successful identification of pertinent structures (L4-L5 spinous processes and the spinal canal) occurred in 100% of patients with normal BMI, 95% of those who were overweight, and 74% of those who were obese. Difficulty in palpating landmarks was noted in 5% of patients with normal BMI, 33% of those who were overweight, and 68% of those who were obese. In subjects with difficult-to-palpate landmarks, US identified pertinent structures in 16 of 21. The average distance from skin to ligamentum flavum was 44 mm in those with normal BMI, 51 mm in those who were overweight, and 64 mm in those who were obese measurements between spinous processes did not vary by BMI. Overall, there was a moderate correlation (0.62) between BMI and the distance from skin to ligamentum flavum.	Population was a convenience sample of adult patients at the ED, not patients undergoing an actual LP. Data not reviewed nor verified by a third party.
Coley, B. et al. 2001 USA	Neonates and infants referred for image-guided lumbar puncture after unsuccessful blind attempts. 32 patients enrolled.	Prospective	Diagnosis of the cause of failed LP when failure has occured and assessment on whether us can provide guidance for LP	23 US studies showed intrathecal and/or epidural echogenic hematoma, 5 showed minimal fluid, and 4 had normal exams. US guidance used 26 times. US guidance provided usable samples in 15 of 26 attempts. In 11 encounters where thecal sac appeared normal with CSF visible, US was always successful. In six encounters where minimal or bloody CSF present, provided usable samples in 4.	Did not compare cause of failed LP found by US versus some other standard imaging study. Did not compare success of LP with US to fluoroscopy.

Comment(s)

All studies found US clinically useful. Two studies had similar design in that they were assessing ability to identify appropriate landmarks. However their results should be considered preliminary as it may not translate into increased rates of success, diminished complication rates for the procedure, or other secondary endpoints related to LP. Coley's study shows us that US can not only be used in real time for CSF collection but can also be a tool to diagnose cause of failed collection and to identify those in which attempting collection may be futile.

Clinical Bottom Line

Ultrasound shows early promise as a tool to assist in achieving a successful lumbar puncture.

References

1. Robinson M. Ferre MD, Timothy W. Sweeney MD Emergency physicians can easily obtain ultrasound images of anatomical landmarks relevant to lumbar puncture American Journal of Emergency Medicine (2007) 25; 291–296
2. Kirk A. Stiffler MD, Sharhabeel Jwayyed MD, Scott T. Wilber MD, Angela Robinson DO The use of ultrasound to identify pertinent landmarks for lumbar puncture American Journal of Emergency Medicine (2007) 25; 331–334
3. Brian D. Coley, William E. Shiels, II, Mark J. Hogan Diagnostic and interventional ultrasonography in neonatal and infant lumbar puncture Pediatric Radiology (2001) 31; 399-402