Lumbar Puncture and Post-Dural Puncture Headaches: Implications for the Emergency Physician

Robert L. Frank, MD, FAAEM

Disclosures

J Emerg Med. 2008;35(2):149-157. 

In This Article

Spinal Needles and Their Relationship to PDPH

There are several characteristics related to the spinal needle used that are critical determinants in development of PDPH. Although these issues have long been part of anesthesia practice, they are rarely considered by other specialists who perform dural puncture procedures.[53,54,55] Thoughtful consideration of these issues is one area in which emergency physicians can have a significant impact on reducing the occurrence of PDPHs. The first issue relates to size of the needle. Larger needles leave larger holes, allow for greater CSF leak and, thus, cause more PDPHs.[7,43,50,53,56,57] The incidence of PDPH with the standard 20- or 22-gauge Quincke cutting beveled needle commonly used by non-anesthetists for diagnostic lumbar puncture is as high as 40%.[9,18,19,20,21] This could be reduced to as low as 5% using a similar 24-27-gauge needle.[58] It has been a long-held belief that the small needles used for performance of spinal anesthetics allow for too-slow fluid collection and unacceptable difficulty for use in the performance of diagnostic lumbar punctures.[7] Carson and Serpell found that use of needles smaller than 22-gauge required >6 min to collect 2 mL of CSF and measurement of opening pressure was similarly slow and potentially inaccurate.[7] Thus, it is felt by some that needles smaller than 22-gauge are inadequate for diagnostic lumbar punctures.[59] Strachan et al., however, showed that 2 mL of CSF could be obtained by gentle aspiration through a 24-gauge needle in <1 min.[60] In addition to using a smaller-gauge needle, using a needle with an atraumatic tip can further reduce the incidence of PDPH, as will be discussed below.

An additional factor important in reducing PDPH is the shape of the tip of the spinal needle. Green, in 1926, showed that blunt-tipped spinal needles that separate dural fibers and allow recoil with minimal tearing significantly reduce CSF leak and PDPH.[61] Holst et al. showed with electron microscopy that atraumatic needles leave smaller holes in the dura that tend not to remain open and have three times less CSF leakage than Quincke (BD, Franklin Lakes, NJ) needles.[62] In recent years, several atraumatic (also known as pencil point or non-cutting) spinal needles have been introduced, with the Sprotte (B. Braun Medical Inc., Bethlehem, PA) and Whitacre (BD, Franklin Lakes, NJ) brands being most commonly used (Figure 1). The anesthesia literature has shown conclusively that atraumatic needles significantly reduce incidence of PDPH compared to cutting Quincke-type needles typically used by non-anesthesia practitioners.[53] Although less studied in diagnostic lumbar puncture, there is evidence to support the use of atraumatic needles for PDPH reduction. Thomas et al. showed that PDPH incidence could be reduced from 54% to 29% if a 20-gauge atraumatic needle was used rather than a Quincke cutting beveled needle.[63] The incidence could be further reduced to 4% when 22-gauge atraumatic spinal needles are used.[23] Strupp et al. found that patients who received a diagnostic lumbar puncture with a 22-gauge atraumatic needle had a PDPH rate of 12.2% vs. 24.4% in those who received lumbar puncture with a 22-gauge Quincke needle.[19] Other investigators have shown similar reductions in PDPH with the use of 22-gauge atraumatic needles.[54,64,65] Other studies have not shown a reduction in PDPH when atraumatic needles were compared to similar-gauge cutting beveled needles. Lenaerts et al. found no benefit when the 20-gauge atraumatic Sprotte needle was compared to the 20-gauge cutting Yale needle (BD Madrid, Spain).[66] These findings are likely related to the fact that even though an atraumatic needle was used, it was a large-bore needle that would cause a sizeable dural rent despite its non-cutting tip. Other investigators also have found no reduction in PDPH after diagnostic lumbar puncture when atraumatic 22-gauge needles were compared with cutting Quincke needles.[67,68] Disadvantages of the atraumatic needles includes increased cost, different "feel" and lack of "pop" that is often felt upon piercing the dura, occasional failure to obtain CSF, and difficulty penetrating the skin due to the dull tip. This last issue can be overcome by insertion of the atraumatic spinal needle through a traditional cutting 18-gauge needle acting as an introducer placed beyond the epidermis. Taking into consideration the desirable characteristics of a spinal needle for use in diagnostic lumbar puncture and the goal of reducing the risk of PDPH, a 24-gauge atraumatic needle may be the needle of choice, especially for those at high risk for PDPH. Atraumatic needles are slightly more expensive than similar Quincke needles (approximately $12 versus $4, respectively), although this cost could be easily offset by the reduced numbers of spinal headaches.[20]

Drawing showing three types of spinal needle tips: the Quincke, the Whitacre, and the Sprotte.

Another factor that significantly reduces likelihood of PDPH when using a cutting beveled Quincke needle is the orientation of the needle tip to the dura. Although the dural fibers in general have no consistent orientation, branching elastic fibers do tend to lie in an orientation that minimizes the size of the opening when the cutting bevel of the needle is inserted parallel to the long axis of the spine.[3,4] This causes fewer fibers to be cut than if the bevel were inserted in a perpendicular orientation. Thus, a smaller hole in the dura is created, less CSF leakage occurs, and there is reduced likelihood of PDPH.[43,52,55,69,70,71] Therefore, insertion of the needle with the cutting bevel parallel to the long axis of the spine is indicated. Tearing of the dura may also occur upon removal of the needle if it is rotated to a perpendicular orientation after insertion.[72] Bevel orientation is not an issue with atraumatic needles, as they tend to separate dura fibers rather than cutting them, allowing them to return to their original position with decreased CSF leakage.[61]

Replacement of the spinal needle stylet before removal of the needle also has been shown to reduce the incidence of PDPH. Strupp et al. found that stylet reinsertion reduced PDPH from 16% to 5% with 21-gauge Sprotte atraumatic needles.[19] It was postulated that a strand of arachnoid mater may be pulled by the open needle on its removal and enter the dural rent, maintaining an opening that allows greater CSF leakage.[19] A similar study has not been performed using cutting Quincke needles. A similar effect may occur if the spinal needle strikes bone upon insertion. This has been reported to cause a burr to develop at the needle tip that will drag the arachnoid mater out as it is withdrawn, thus creating a CSF leak.[73] This concept has not been formally studied.

Use of bed rest to prevent PDPH was first advocated by Bier in 1899.[20] It is still advocated by many that a patient must have some period of bed rest after a lumbar puncture to prevent PDPH. A meta-analysis by Thoennisen et al. and a Cochrane review by Sudlow and Warlow evaluated all studies on this topic and found no difference in incidence of PDPH for those with immediate mobilization vs. bed rest for up to 24 h.[29,74] Thus, bed rest after lumbar puncture has no role in PDPH prevention.

It is advocated by some that increased hydration after dural puncture will minimize PDPH occurrence, possibly by increasing the rate of production of CSF to replace the fluid lost from leakage. This was not found to be beneficial in the only study that has examined this issue.[75] Thus, it would seem that intake of additional fluids after a lumbar puncture does not assist in PDPH prevention.[76]

The position that the patient is placed in during LP has been postulated to play a role in the development of PDPH.[77] A controlled study did not show the position used during performance of LP to have a relationship to development of PDPH.[78] Strategies the emergency physician can employ to reduce the risk of PDPH are summarized in Table 2 .

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