by Connie Deline, MD

This new prospective study deserves a spotlight here.

Lumbar puncture is the most common cause of a spinal CSF leak and is known as a post-dural puncture headache (PDPH). Because smaller needles and non-cutting needles have been shown repeatedly to reduce the risk of post-dural puncture headache, the authors of this study proceeded with a prospective study to compare the outcomes using a 22 gauge cutting needle or a 25 gauge non-cutting needle for diagnostic lumbar punctures. The lumbar punctures were performed by first year neurology residents with assistance from a neurology associate or anesthesiologist when needed.

Of the patients that completed the study, the 22 gauge cutting needle was used in 199 while the 25 gauge non-cutting needle was used in 205. PDPH developed in 50 of 199 patients after lumbar puncture using the 22 gauge cutting needle (25%) compared with 21 of 205 patients after lumbar puncture with the non-cutting 25 gauge needle (10%). Severe PDPH occurred in 20% of the patients where the cutting needle was used and 7% of the patients where the smaller atraumatic needle was used.

Measures of disability were also assessed. They found that total days off work was much higher in the group with cutting needles as compared with the non-cutting needles (175 versus 55). Total days bedridden was 217 versus 102.

They also found that the need for associate assistance was lower with the non-cutting needles.

Overall costs were much lower using the smaller non-cutting needles.

The authors commented as follows:
“Despite the overwhelming evidence in support of the use of smaller, non-cutting needles for diagnostic lumbar punctures, the use of larger cutting needles is still widespread in neurological departments. In our outpatient clinic, where a cutting 22 G needle had previously been the needle of choice, we performed a prospective, interventional study, in order to test the feasibility, drawbacks, and potential benefits of changing the needle to a 25 G non-cutting needle. While adjusting for potential confounders, we were able to confirm the findings of previous studies, namely, that using a smaller, non-cutting needle significantly reduces the risk of PDPH.”

While many patients with PDPH have resolution of their symptoms with conservative treatment such as rest, fluids, caffeine and time, a significant proportion require one or more epidural blood patches and a few require open surgical repair. Prevention is always a better option.

With clear evidence of lower incidence of PDPH and lower overall costs, neurology departments and emergency room departments may wish to revisit their protocols for diagnostic lumbar punctures. While a smaller needle and/or non-cutting needle may not be suitable for every lumbar puncture, availability of non-cutting needles on lumbar puncture trays for use where possible makes sense.

This publication is open access and link to full text is included below.

Changing the needle for lumbar punctures: Results from a prospective study
Engedal TS, Ørding H, Vilholm OJ.
Clin Neurol Neurosurg. 2015 Mar;130:74-9. doi: 10.1016/j.clineuro.2014.12.020. Epub 2015 Jan 6.
Post-dural puncture headache (PDPH) is a common complication of diagnostic lumbar punctures. Both a non-cutting needle design and the use of smaller size needles have been shown to greatly reduce the risk of PDPH. Nevertheless, larger cutting needles are still widely used. This study describes the process of changing the needle in an outpatient clinic of a Danish neurology department.
Prospective interventional trial. Phase 1: 22G cutting needle. Phase 2: 25G non-cutting needle. Practical usability of each needle was recorded during the procedure, while the rate of PDPH and the occurrence of socioeconomic complications were acquired from a standardized questionnaire.
651 patients scheduled for diagnostic lumbar punctures were screened for participation and 501 patients were included. The response rate was 80% in both phases. In phase 2, significant reductions were observed in occurrence of PDPH (21 vs 50, p=0.001), number of days spent away from work (55 vs 175, p<0.001), hospitalizations (2 vs 17, p<0.001), and number of bloodpatch treatments (2 vs 10, p=0.019). Furthermore, during the procedure, both the need for multiple attempts (30% vs 44%, p=0.001), and the failure-rate of the first operator (17% vs 29%, p=0.005) were reduced. CONCLUSIONS: Our study showed that smaller, non-cutting needles reduce the incidence of PDPH and are easily implemented in an outpatient clinic. Changing the needle resulted in fewer socioeconomic complications and fewer overall costs, while also reducing procedural difficulty. PMID: 25590665
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