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LETTER TO EDITOR
Year : 2017  |  Volume : 33  |  Issue : 4  |  Page : 563-564

Subarachnoid space needle's eyelet in dural-arachnoid side-wall of lumbar cistern: Whitacre vs. Quincke


Department of Anesthesiology, Detroit Medical Center, Wayne State University, Detroit, Michigan, United States

Date of Web Publication9-Jan-2018

Correspondence Address:
Deepak Gupta
Department of Anesthesiology, School of Medicine, Wayne State University, Box No. 162, 3990 John R, Detroit, Michigan 48201
United States
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9185.173361

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How to cite this article:
Gupta D. Subarachnoid space needle's eyelet in dural-arachnoid side-wall of lumbar cistern: Whitacre vs. Quincke. J Anaesthesiol Clin Pharmacol 2017;33:563-4

How to cite this URL:
Gupta D. Subarachnoid space needle's eyelet in dural-arachnoid side-wall of lumbar cistern: Whitacre vs. Quincke. J Anaesthesiol Clin Pharmacol [serial online] 2017 [cited 2019 Jan 16];33:563-4. Available from: http://www.joacp.org/text.asp?2017/33/4/563/173361



Sir,

I sincerely appreciated reading “spinal anesthesia and direction of spinal needle bevel”[1] written in response to my letter “subarachnoid space needle manipulations for a successful block.”[2] The response adequately highlighted the differences between Quincke needle (cutting tip type) and Whitacre needle (pencil point tip type) in regard to the mechanics of exiting local anesthetics' flow from these needles. However, my letter was emphasizing about the position of the exit-point (eyelet in case of Whitacre needle and terminal end in case of Quincke needle) in respect to the overall lumbar cistern in the transverse plane. The flow and direction of exiting local anesthetics are secondary objectives because the primary objective is to ensure that the exit-point of blindly placed subarachnoid needle is in the center of the cerebrospinal fluid (CSF) filled lumbar cistern. This is to ensure high success rates of effective subarachnoid anesthesia as well as to avoid delivery of local anesthetics through needle's exit-point that could have been inadvertently/blindly placed near to/within the intrathecal/extradural nerve roots because this unwarranted proximity to these nerve roots may cause partial-to-no subarachnoid anesthesia with potential direct exposure of these nerve roots to high concentrations of local anesthetics that may present as postanesthesia complications of transient-to-long-term neurological deficits. As subarachnoid needle placement is a blind procedure and the exit-point can end up being in one of the dural-arachnoid side-walls of this lumbar cistern as visualized, it is important to realize that re-directioning when performed in calculated manner can provide better success rates by ensuring the exit-point of the needle and subsequent delivery of medications in lumbar cistern's central pool of CSF rather than away from it or outside it. There is a difference in diagnostic lumbar puncture versus subarachnoid anesthesia because the diagnostic lumbar puncture's goal is to just collect CSF irrespective of its flow rates whereas subarachnoid anesthesia requires that appropriate CSF flow rate/aspiration should be ensured before injecting medications, otherwise the goal of successful block will not be achieved. My letter had tried to focus on this aspect only. As mentioned in my letter at the beginning of the third paragraph, the subarachnoid needle manipulations advised in my letter are not meant for Quincke needle because the Quincke needle has cutting tip with no true “eyelet” and medication exits from its terminal end itself. Moreover, as the cutting edge of Quincke needle is completely open on one side with opening extending/slanting to both side-edges of needle's exit-point, it becomes improbable to ensure the guidance of calculated re-directioning with Quincke needle as advised in my letter. Comparatively, the eyelet in Whitacre needle is rectangular and restricted to only one of the four “surfaces” of conical (approximately curvilinear rectangular) shaped pencil tip thus allowing the guidance aimed to be achieved by calculated re-directioning advised in my letter. In summary, the points raised by the respondent author are valid in regards to Quincke needle rotations while performing subarachnoid block; however, it is my limited understanding that calculated re-directioning can be performed with Whitacre needle only wherein the aim is to ensure that eyelet needs to be in the central CSF pool before any local anesthetics is administered so that failures of subarachnoid anesthesia occurring due to Whitacre needle's eyelet being inadvertently placed in dural-arachnoid side-walls can be avoided.



 
  References Top

1.
Prakash S, Mullick P. Spinal anesthesia and direction of spinal needle bevel. J Anaesthesiol Clin Pharmacol 2016;32:268-9.  Back to cited text no. 1
[PUBMED]  [Full text]  
2.
Gupta D. Subarachnoid space needle manipulations for successful block. J Anaesthesiol Clin Pharmacol 2014;30:444-6  Back to cited text no. 2
    




 

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