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Novel method of locating the foramen ovale: a stable chair with solid legs
  1. Liangliang He1 and
  2. Zhonghui Guan2
  1. 1Department of Pain Management, Xuanwu Hospital, Capital Medical University, Beijing, China
  2. 2Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA
  1. Correspondence to Dr Zhonghui Guan, Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA; zhonghui.guan{at}

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To the Editor

We have read the comments from De Cordoba et al1 regarding our recently published paper on a novel method to quickly identify the foramen ovale (FO) under fluoroscopy.2

In their comments,1 De Cordoba et al suggest that our method is ‘chapter and verse’ of the paper they published in 2015, in which they described a method to follow the petrous ridges to identify the FO.3 We do not agree with their opinion, because we believe that our method is original and has advantages.

We never claimed that we were the first one to identify the relationship between the FO and the petrous ridge. In fact, we acknowledged their ‘petrous ridge’ method by citing their work in our paper.2 However, the petrous ridge is difficult to identify and to follow under fluoroscopy as they described. Quite often many C-arm back and forth adjustments and prolonged procedure time are required to follow their ‘petrous ridge’ method, which is probably one of the reasons why this method has not been widely accepted in clinical practice. In sharp contrast, with our approach, the ‘H-figure’ can be visualized in the fluoroscopic view in the majority of the cases, especially with the medial end of the temporomandibular joint as the landmark for the S–P–T line. The rest of the fluoroscopic time is used to optimize the FO view.

De Cordoba et al suggest that the final image of the FO in their method is very similar to our ‘H-figure’ image. However, they are comparing their final image, after multiple fluoroscopic adjustments, with our initial fluoroscopic image. In fact, their arguments confirm that our ‘H-figure’ method is correct and reliable. The final fluoroscopic image of the FO from any method should be similar, and this should not be used as a criterium to judge the originality of the method. The key point is how easy and reliable it is to get the final optimized image.



  • Correction notice This article has been corrected since it published Online First. The first author's name has been corrected.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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