scholarly journals The depth of the facial nerve in the mastoid bone

2018 ◽  
Vol 4 (3) ◽  
pp. 666
Author(s):  
B. Y. Praveen Kumar ◽  
K. T. Chandrashekhar ◽  
M. K. Veena Pani ◽  
Sunil K. C. ◽  
Anand Kumar S. ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Significant Variation ◽  
Canal Wall ◽  
Stylomastoid Foramen ◽  
Cortical Mastoidectomy ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy ◽  
The Mean ◽  
Temporal Bones

<p class="abstract"><strong>Background:</strong> The hallmark of the temporal bone is variation. Various important structures like the facial nerve run in the temporal bone at various depths which can be injured during mastoidectomy.</p><p class="abstract"><strong>Methods:</strong> Twenty wet cadaveric temporal bones were dissected. A cortical mastoidectomy was performed followed by a canal wall down mastoidectomy and the depth of the vertical segment of the facial nerve in the mastoid was determined.  </p><p class="abstract"><strong>Results:</strong> The mean depth of the second genu was 13.82 mm. The mean depth of the stylomastoid foramen was 12.75 mm and the mean distance from the annulus at 6’0 clock to the stylomastoid foramen was 10.22 mm.</p><p><strong>Conclusions:</strong> There is significant variation in the average depth of the facial nerve in the mastoid. </p>

Cochlear implantation in the irradiated temporal bone

2006 ◽  
Vol 121 (1) ◽  
pp. 83-86 ◽  
Author(s):  
O F Adunka ◽  
C A Buchman
Keyword(s):  
Hearing Loss ◽  
Facial Nerve ◽  
Temporal Bone ◽  
Cochlear Implantation ◽  
Flap Reconstruction ◽  
Canal Wall ◽  
Free Flap Reconstruction ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy ◽  
Electrode Insertion

Objective: To demonstrate the feasibility and complexities of cochlear implantation in the setting of bilateral temporal bone osteoradionecrosis.Study design: Case report.Setting: Tertiary care referral centre.Case description: A 66-year-old woman with bilateral temporal bone osteoradionecrosis and profound hearing loss, following treatment for tonsillar cancer, underwent cochlear implantation. Prior canal wall down mastoidectomy and subsequent temporal bone resection with free flap reconstruction had been performed on the implanted ear. The contralateral ear received a canal wall down mastoidectomy. A completely dehiscent mastoid segment of the facial nerve and extensive fibrosis were evident in the implanted ear. Only minimal fibrous reaction was found within the cochlea, allowing for full electrode insertion. At three months, speech recognition testing documented a consonant-nucleus-consonant (CNC) word score of 54 per cent.Conclusions: This report demonstrates the feasibility of cochlear implantation after temporal bone surgery and free flap reconstruction in the setting of diffuse osteoradionecrosis. The patient's excellent open-set speech understanding using the cochlear implant implies that radiation did not severely damage the central auditory pathways. Thus, some patients with radiation-induced hearing loss may be appropriate cochlear implant candidates. Special attention should be paid to surgical planning, as complications related to wound healing, electrode insertion and facial nerve injury may be more likely.

scholarly journals Repair of Temporal Bone Encephalocele following Canal Wall Down Mastoidectomy

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Sarantis Blioskas ◽  
Ioannis Magras ◽  
Stavros Polyzoidis ◽  
Konstantinos Kouskouras ◽  
Georgios Psillas ◽  
...  
Keyword(s):  
Temporal Bone ◽  
Chronic Otitis Media ◽  
Base Deficit ◽  
Layer By Layer ◽  
Canal Wall ◽  
Temporalis Fascia ◽  
Dural Graft ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy

We report a rare case of a temporal bone encephalocele after a canal wall down mastoidectomy performed to treat chronic otitis media with cholesteatoma. The patient was treated successfully via an intracranial approach. An enhanced layer-by-layer repair of the encephalocele and skull base deficit was achieved from intradurally to extradurally, using temporalis fascia, nasal septum cartilage, and artificial dural graft. After a 22-month follow-up period the patient remains symptom free and no recurrence is noted.

Acoustic Mechanisms

1998 ◽  
Vol 118 (6) ◽  
pp. 751-761 ◽  
Author(s):  
KENNETH R. WHITTEMORE ◽  
SAUMIL N. MERCHANT ◽  
JOHN J. ROSOWSKI
Keyword(s):  
Middle Ear ◽  
Sound Transmission ◽  
Canal Wall ◽  
Air Space ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy ◽  
Temporal Bones ◽  
Head Neck ◽  
Canal Wall Up ◽  
Space Volume

The contribution of the middle ear air spaces to sound transmission through the middle ear in canal wall-up and canal wall-down mastoidectomy was studied in human temporal bones by measurements of middle ear input impedance and sound pressure difference across the tympanic membrane for the frequency range 50 Hz to 5 kHz. These measurements indicate that, relative to canal wall-up procedures, canal wall-down mastoidectomy results in a 1 to 5 dB decrease in middle ear sound transmission below 1 kHz, a 0 to 10 dB increase between 1 and 3 kHz, and no change above 3 kHz. These results are consistent with those reported by Gyo et al. (Arch Otolaryngol Head Neck Surg 1986;112:1262-8), in which umbo displacement was used as a measure of sound transmission. A model analysis suggests that the reduction in sound transmission below 1 kHz can be explained by the smaller middle ear air space volume associated with the canal wall-down procedure. We conclude that as long as the middle ear air space is aerated and has a volume greater than 0.7 ml, canal wall-down mastoidectomy should generally cause less than 10 dB changes in middle ear sound transmission relative to the canal wall-up procedure. (Otolaryngol Head Neck Surg 1998;118:751-61.)

scholarly journals Morphometry of the Digastric Ridge and Its Significance for Mastoid Surgeries—A Cadaveric Study

2019 ◽  
pp. 014556131987049
Author(s):  
David Victor Kumar Irugu ◽  
Anup Singh ◽  
Rajeev Kumar
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Sigmoid Sinus ◽  
Risk Of Injury ◽  
Temporal Bone Pneumatization ◽  
Important Landmark ◽  
The Mean ◽  
Temporal Bones ◽  
Digital Caliper ◽  
Reduced Risk

Objective: Digastric ridge (DR) is an important landmark to locate facial nerve (FN) and sigmoid sinus for mastoid surgeries and transmastoid approaches. We aim to look for the effect of temporal bone pneumatization on the morphometry of the DR and its relation to the adjoining structures. Methods: Temporal bones were harvested from unclaimed cadavers after the approval of the ethical committee. The dissection of the temporal bones was performed under a microscope, and the length of the DR and the distance between the mastoid segment of the FN and the anterior end of DR (FN-DR distance) were measured using a digital caliper. Stata version 14.0 was used to perform the statistical calculations. Results: Ninety-three temporal bones were microdissected (right:left = 47:46; well pneumatized:poorly pneumatized = 58:35). Mean length of the DR was 17.1 mm and was significantly longer in well-pneumatized bones ( P = .0000). The mean distance between the anterior end of the digastric ridge and the mastoid part of the facial nerve was 4 mm. The distance was significantly more in well-pneumatized bones. Conclusion: Prominence and the length of the DR, as well as the FN-DR distance, are significantly more in well-pneumatized bones compared to poorly pneumatized bones. This finding has potential surgical implications with reduced risk of injury to the FN resulting from a conspicuous DR in well-pneumatized bones.

External Auditory Canal Reconstruction and Mastoid Obliteration Using Modified Palva Flap in Canal Wall Down Mastoidectomy With Tympanoplasty

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 69S-75S
Author(s):  
Ji-Sun Kim ◽  
Il Gye Lim ◽  
Jeong-Hoon Oh ◽  
Byung Guk Kim ◽  
Ki-Hong Chang
Keyword(s):  
Temporal Bone ◽  
External Auditory Canal ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Canal Wall ◽  
Mastoid Obliteration ◽  
Before And After ◽  
The Status ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy

Objective: To evaluate the effectiveness of a modified Palva flap used for external auditory canal reconstruction and mastoid obliteration in canal wall down mastoidectomy. Methods: We retrospectively analyzed patients who underwent canal wall down mastoidectomy with tympanoplasty using modified Palva flap. All patients underwent pure tone audiometry and temporal bone computed tomography (CT) before surgery, and the same tests were performed in the first year after surgery. The external auditory canal volumes were calculated by summing the areas of each section selected in temporal bone CT. For each patient, the ratio of external auditory canal volume was calculated from CT taken before and after surgery. Results: The mean of external auditory canal volume after canal wall down with a modified Palva flap was about 1.4 times larger than before surgery. The modified Palva flap is effective for the reconstruction of the external auditory canal. Both pure tone audiometry level and air-bone gap showed statistically significant improvement after surgery ( Ps = .001 and .002, respectively). Conclusions: The external auditory canal volume slightly increased, but the status of mastoid obliteration was well maintained 1 year after surgery. The modified Palva flap used in this study is an easy and effective method in external auditory canal reconstruction and mastoid obliteration.

Synchronous ossiculoplasty with titanium prosthesis during canal wall down surgery for advanced cholesteatoma: anatomical and hearing outcomes

2011 ◽  
Vol 126 (2) ◽  
pp. 131-135 ◽  
Author(s):  
M Iseri ◽  
E Ustundag ◽  
A Ulubil ◽  
M Ozturk ◽  
O Bircan
Keyword(s):  
Bone Conduction ◽  
Functional Results ◽  
Ossicular Chain ◽  
Single Stage ◽  
Canal Wall ◽  
Ossicular Replacement ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy ◽  
The Mean ◽  
Hearing Outcomes

AbstractObjective:To analyse patients with cholesteatoma undergoing canal wall down mastoidectomy together with ossicular reconstruction with a titanium prosthesis, in order to identify factors associated with hearing outcomes.Study design:Retrospective review of 97 cases undergoing single-stage surgical management.Methods:All patients underwent canal wall down mastoidectomy. Kurz titanium ossicular prostheses were used for ossicular chain reconstruction. Pre-operative and post-operative air conduction and bone conduction hearing thresholds were obtained at 500, 1000, 2000 and 3000 Hz.Results:The mean pure tone average improved from 46.02 ± 14.54 dB pre-operatively to 29.32 ± 14.64 dB post-operatively, for both total and partial ossicular replacement prosthesis groups combined. The mean air–bone gap improved from 30.38 ± 11.12 dB pre-operatively to 15.62 ± 9.65 dB post-operatively, for both groups combined.Conclusion:Reconstruction with a titanium prosthesis offers good functional results when performed during canal wall down surgery for advanced cholesteatoma, as a single-stage procedure.

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