Anatomic Limitations of Posterior Tympanotomy

Dong-Hee, Lee; Kim, Jun-Kyu; Seo, Jae‐Hyun; Lee, Beom-Jun

doi:10.1097/scs.0b013e31824e6ca7

Cited by 25 publications

(12 citation statements)

References 6 publications

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“…In this study, there was one case with an overhanging posterior wall, and one with a high riding jugular bulb. In our cohort and in previous studies, the obscuration of the facial recess opening by the posterior wall or sigmoid sinus and jugular bulb is a rare phenomenon (< 1%) [14,18]. Some surgeons advocate in cases of an overhanging posterior wall, to "green stick fracture" the posterior wall medially (just lateral from the FN and push it forward) providing improved exposition of the RWM, access to the middle ear and perform implantation of the electrode array; then replace the (partly mobile) canal wall to its previous position where bone will regrow.…”

Section: Operative Reportsupporting

confidence: 67%

“…These results show that the FN-CTN distance indeed provides a realistic estimate of the size of the 'window' to the middle ear structures [16]. A previous study also showed that the FN-CTN distance in the mastoid is important for the viewing angle through the facial recess opening [18]. Two other studies in adults showed no effect of the facial recess width on the visibility of the RW [10,12].…”

Section: Facial-chorda Tympani Nerve Distancesupporting

confidence: 57%

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Radiological and surgical aspects of round window visibility during cochlear implantation: a retrospective analysis

Jwair

Eijden

Blijleven

et al. 2021

Eur Arch Otorhinolaryngol

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Purpose The round window approach has become the most preferred option for cochlear implant (CI) insertion, however, sometimes it may not be possible due to the (in)visibility of the round window membrane (RWM). We addressed the prevalence, consequences and indicators of difficult detection of the RWM in cochlear implant surgery. Methods This study retrospectively analysed the operative reports and preoperative high resolution axial-computed tomography (CT) scans of a consecutive cohort of patients who underwent a CI insertion. The main outcomes were surgical outcomes of the RW approach, and assessment of radiological markers. Results The operative reports showed that RWM insertion was feasible in 151 out of 153 patients. In 18% of the patients the RWM was difficult to visualize. All these patients had at least one intraoperative event. The chorda tympani nerve (CTN) or posterior canal wall was affected in 8% of the 153 patients and the fallopian canal in 6%. These patients had a facial-chorda tympani nerve distance on the CT scan that was considerably smaller than normal patients (1.5 mm vs 2.3 mm). In addition, a prediction line towards the anterolateral side of the RWM was found to be more prevalent in these patients’ CT scans (sensitivity 81%, specificity 63%). Conclusion The RW approach is feasible in almost all patients undergoing CI surgery. Difficult visualisation of the RWM seems to lead to at least one intraoperative event. Radiological measures showed that these patients had a smaller facial recess and a more anteriorly placed facial nerve, which can be used to better plan a safe insertion approach.

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Section: Operative Reportsupporting

confidence: 67%

Section: Facial-chorda Tympani Nerve Distancesupporting

confidence: 57%

Radiological and surgical aspects of round window visibility during cochlear implantation: a retrospective analysis

Jwair

Eijden

Blijleven

et al. 2021

Eur Arch Otorhinolaryngol

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“…Several studies have sought to establish radiologic measurements that can predict degree of visualization during a standard facial recess approach (42,68,69). Of particular interest are the total FR area, the EAC angle and FN location.…”

Section: Discussionmentioning

confidence: 99%

Anatomical Correlates and Surgical Considerations for Localized Therapeutic Hypothermia Application in Cochlear Implantation Surgery

Perez¹,

Viziano

Al-Zaghal³

et al. 2019

Otology &Amp; Neurotology

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Hypothesis:Application of localized, mild therapeutic hypothermia during cochlear implantation (CI) surgery is feasible for residual hearing preservation.Background:CI surgery often results in a loss of residual hearing. In preclinical studies, local application of controlled, mild therapeutic hypothermia has shown promising results as a hearing preservation strategy. This study investigated a suitable surgical approach to deliver local hypothermia in patients utilizing anatomical and radiologic measurements and experimental measurements from cadaveric human temporal bones.Methods:Ten human cadaveric temporal bones were scanned with micro-computed tomography and anatomical features and measurements predicting round window (RW) visibility were characterized. For each bone, the standard facial recess and myringotomy approaches for delivery of hypothermia were developed. The St. Thomas Hospital (STH) classification was used to record degree of RW visibility with and without placement of custom hypothermia probe. Therapeutic hypothermia was delivered through both approaches and temperatures recorded at the RW, RW niche, over the lateral semicircular canal and the supero-lateral mastoid edge.Results:The average facial recess area was 13.87 ± 5.52 mm2. The introduction of the cooling probe through either approach did not impede visualization of the RW or cochleostomy as determined by STH grading. The average temperatures at RW using the FR approach reduced by 4.57 ± 1.68 °C for RW, while using the myringotomy approach reduced by 4.11 ± 0.98 °C for RW.Conclusion:Local application of therapeutic hypothermia is clinically feasible both through the facial recess and myringotomy approaches without limiting optimal surgical visualization.

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“…In a previous study, Lee et al reported that the angle between the cortex of the external ear canal and the FN was highly correlated with visibility through posterior tympanotomy. 42 They suggested that pneumatic mastoids, but not sclerotic mastoids, could have a more complex relationship with FR anatomy, including various other factors that were not considered in their study.…”

Section: Discussionmentioning

confidence: 93%

Anatomical Study of the Facial Recess with Implications in Round Window Visibility for Cochlear Implantation: Personal Observations and Review of the Literature

Jain

Deshmukh

Lakhotia

et al. 2019

Int Arch Otorhinolaryngol

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Introduction Posterior tympanotomy through facial recess (FR) is the conventional and most preferred approach to facilitate cochlear implantation, especially when the electrode is inserted through the round window. The complications of the FR approach can be minimized by proper understanding of the anatomy of the FR. Objective The present study was undertaken to assess the various parameters of FR and round window visibility, which may be of relevance for cochlear implant surgery. Methods Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of FR and posterior tympanum. Photographs were taken with an 18 megapixels digital camera, which were then imported to a computer to determine various parameters. Results The mean distance from the take-off point/crotch of the chorda tympani nerve (CTN) to the stylomastoid foramen was 4.08 ± 0.8 mm (range of 2.06 - 5.5 mm). The variations in the course of the CTN included origin at the level of the lateral semicircular canal. The mean chorda-facial angle in our study was 26.91° ± 1.19°, with a range of 25° to 28.69°. The mean FR length ranged between 9.4 mm and 18.56 mm (mean of 12.41 ± 2.91mm) and varied with the origin of the CTN and pneumatization of temporal bone. The average maximum width of the FR was 2.93 ± 0.4 mm (range 2.24–3.45 mm) and the mean width of the FR at the level of the round window was 2.65 ± 0.41 mm. Conclusion The FR approach provides good access to the round window membrane in all cases. In some cases, table adjustment is required.

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Anatomic Limitations of Posterior Tympanotomy

Cited by 25 publications

References 6 publications

Radiological and surgical aspects of round window visibility during cochlear implantation: a retrospective analysis

Radiological and surgical aspects of round window visibility during cochlear implantation: a retrospective analysis

Anatomical Correlates and Surgical Considerations for Localized Therapeutic Hypothermia Application in Cochlear Implantation Surgery

Anatomical Study of the Facial Recess with Implications in Round Window Visibility for Cochlear Implantation: Personal Observations and Review of the Literature

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