title: Bevel direction and postdural puncture headache: a meta-analysis.
abstract: BACKGROUND
  The effect of lumbar puncture needle bevel direction on the incidence of postdural puncture headache (PDPH) is somewhat controversial. We performed a meta-analysis of available trials to determine if bevel direction during lumbar puncture would influence the incidence of PDPH.
  
  
  RESULTS
  Studies were identified primarily by searching the National Library of Medicine's PubMed database (1966 to November 29, 2004) and abstracts from several national meetings (American Society of Anesthesiology, International Anesthesia Research Society, American Society of Regional Anesthesia, Society of Obstetric Anesthesia and Perinatology) for terms related to needle and bevel direction. Inclusion criteria were assessment of the incidence of PDPH after lumbar puncture with a cutting needle (eg, Quincke, Tuohy), comparison of a "parallel" (bevel oriented in a longitudinal or cephalad to caudad direction) to "perpendicular" (bevel oriented in a transverse direction) orientation during needle insertion, randomized trials, and trials primarily in adult populations. Data on study characteristics and incidence of PDPH were abstracted from qualified studies and subsequently analyzed. The search resulted in 52 abstracts from which the original articles were obtained and data abstracted, with ultimately a total of 5 articles meeting all inclusion criteria. Insertion of a non-pencil-point/cutting needle with the bevel oriented in a parallel/longitudinal fashion resulted in a significantly lower incidence of PDPH compared with that oriented in a perpendicular/transverse fashion (unadjusted rates of 10.9% versus 25.8%; odds ratio = 0.29 [95% CI = 0.17-0.50]).
  
  
  CONCLUSIONS
  Our meta-analysis indicates that with use of a cutting needle, insertion in a parallel/longitudinal fashion may significantly reduce the incidence of PDPH, although the reasons for this decrease are unclear.
authors.affiliation: Department of Anesthesiology, The Johns Hopkins University, Baltimore, Maryland 21287, USA. jrichma1@jhmi.edu
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Richman
authors.forename: Emily M
authors.initials: EM
authors.lastname: Joe
authors.forename: Seth R
authors.initials: SR
authors.lastname: Cohen
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Rowlingson
authors.forename: Robert K
authors.initials: RK
authors.lastname: Michaels
authors.forename: Maggie A
authors.initials: MA
authors.lastname: Jeffries
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Wu
mesh_terms: D001099:Arachnoid / Q000473:pathology; D004388:Dura Mater / Q000473:pathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009339:Needles; D051299:Post-Dural Puncture Headache / Q000453:epidemiology*; D013129:Spinal Puncture / Q000009:adverse effects* / Q000379:methods*