28 July 2013
Sir, We would like to respond to your major lingering uncertainty in the consideration of superior canal dehiscence acting as a third mobile window.1 Multiple analyses have shown that there is little difference whether a dehiscence or model canal fenestra opens to air or the fluid-filled brain case.2,3 The important distinction, in this regard, is not the difference in the characteristic impedance of air vs. water, but in the very large acoustic impedance of the narrow fluid-filled canal remnant compared to the relatively small impedance of either a water-filled brain case or an air-filled middle ear (or mastoid or bulla). With either termination, the ratio of the acoustic impedance between the canal pathway and the dehiscence termination is at least a factor of 100. Simply put, the impedance along the pathway through the canal and the dehiscence is so overwhelmingly governed by the high impedance of the thin canal that the additional impedance from the interface on the other side of the dehiscence is negligible. Conflict of interest
None to declare.
References 1 Browning G.G. (2013) Response to Drs Carey et al. Clin. Otolaryngol. 38, 99–101 2 Songer J.E. & Rosowski J.J. (2007) A mechano-acoustic model of the effect of superior canal dehiscence on hearing in chinchilla. J. Acoust. Soc. Am. 122, 943–951 3 Kim N., Steele C.R. & Puria S. (2013) Superior-semicircular-canal dehiscence: effects of location, shape, and size on sound conduction. Hear. Res. 301, 72–84
Editorial response to Carey et al It is Editorial policy not to allow letters of correspondence on published articles to continue after the first exchange of views. However in this instance rejection of this second letter from Carey et al could be construed as the Editor rejecting a letter that does not support his own personal views. The essence of his previous response was that animal studies cannot be relied upon to inform us of clinical syndromes and in particular of superior semicircular dehiscence syndrome. The citing of two additional animal studies does not address that opinion The Editor
Carey, J.P.,* Rosowski, J.J.,† Ward, B.K.* & Minor, L.B.‡ *Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA; † Department of Otology and Laryngology, Harvard Medical School, Boston, MA, USA; ‡ Stanford University School of Medicine, Stanford, CA, USA E-mail: [email protected]
Re: Secondary tracheo-oesophageal fistula creation without rigid oesophagoscopy 10 February 2013
Sir, We reviewed with interest the previous publication about tracheo-oesophageal fistula creation.1 As discussed, the method employed involves the use of a rigid oesophagoscope to directly visualise the cervical oesophagus © 2013 John Wiley & Sons Ltd Clinical Otolaryngology 38, 443–447
and facilitate access to the posterior tracheal wall to allow tracheo-oesophageal fistula formation.2 This method can be challenging in the post-radiotherapy patient having tissue fibrosis and/or limited neck extension. 443
CORRESPONDENCE: LETTERS
Re: Response to Drs Carey et al.
Sir, We would like to respond to your major lingering uncertainty in the consideration of superior canal dehiscence acting as a third mobile window.1 Multiple analyses have shown that there is little difference whether a dehiscence or model canal fenestra opens to air or the fluid-filled brain case.2,3 The important distinction, in this regard, is not the difference in the characteristic impedance of air vs. water, but in the very large acoustic impedance of the narrow fluid-filled canal remnant compared to the relatively small impedance of either a water-filled brain case or an air-filled middle ear (or mastoid or bulla). With either termination, the ratio of the acoustic impedance between the canal pathway and the dehiscence termination is at least a factor of 100. Simply put, the impedance along the pathway through the canal and the dehiscence is so overwhelmingly governed by the high impedance of the thin canal that the additional impedance from the interface on the other side of the dehiscence is negligible. Conflict of interest
None to declare.
References 1 Browning G.G. (2013) Response to Drs Carey et al. Clin. Otolaryngol. 38, 99–101 2 Songer J.E. & Rosowski J.J. (2007) A mechano-acoustic model of the effect of superior canal dehiscence on hearing in chinchilla. J. Acoust. Soc. Am. 122, 943–951 3 Kim N., Steele C.R. & Puria S. (2013) Superior-semicircular-canal dehiscence: effects of location, shape, and size on sound conduction. Hear. Res. 301, 72–84
Editorial response to Carey et al It is Editorial policy not to allow letters of correspondence on published articles to continue after the first exchange of views. However in this instance rejection of this second letter from Carey et al could be construed as the Editor rejecting a letter that does not support his own personal views. The essence of his previous response was that animal studies cannot be relied upon to inform us of clinical syndromes and in particular of superior semicircular dehiscence syndrome. The citing of two additional animal studies does not address that opinion The Editor
Carey, J.P.,* Rosowski, J.J.,† Ward, B.K.* & Minor, L.B.‡ *Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA; † Department of Otology and Laryngology, Harvard Medical School, Boston, MA, USA; ‡ Stanford University School of Medicine, Stanford, CA, USA E-mail: [email protected]
Re: Secondary tracheo-oesophageal fistula creation without rigid oesophagoscopy 10 February 2013
Sir, We reviewed with interest the previous publication about tracheo-oesophageal fistula creation.1 As discussed, the method employed involves the use of a rigid oesophagoscope to directly visualise the cervical oesophagus © 2013 John Wiley & Sons Ltd Clinical Otolaryngology 38, 443–447
and facilitate access to the posterior tracheal wall to allow tracheo-oesophageal fistula formation.2 This method can be challenging in the post-radiotherapy patient having tissue fibrosis and/or limited neck extension. 443
CORRESPONDENCE: LETTERS
Re: Response to Drs Carey et al.
