High Resolution X‐ray Micro‐Tomography of the Posterior Ampullary Nerve
Bibliographic record
Abstract
Introduction The posterior ampullary (singular) nerve runs from the posterior ampulla to the saccular nerve (forming the inferior vestibular nerve) through the singular canal of Morgagni in temporal bone. Posterior ampullary neurectomy can be proposed in a few chronically disabling benign paroxysmal positional vertigo. The purpose of this study is to investigate the surgical anatomy of the posterior ampullary nerve using 3D reconstructions high resolution X‐ray micro‐tomography. Materials and Methods 10 human petrous parts of temporal bones were fixed with Winckler's solution. CT images were acquired with a CT scanner (Skyscan 1076, Bruker, Kontich, Belgium). The camera was continuously rotated by 180° and the following parameters were used for acquisition: 50 kV, 0.5 mm Al filter, 200 A source current, 35 m isotropic resolution, 180 ms exposure time, and 0.7° rotation step. The projections were reconstructed with a filtered backprojection algorithm in Skyscan software (NRecon, Skyscan). Reconstructed images were analyzed with ORS Visual software (v1.5, Montreal) which allowed multiple display and post‐processing possibilities (3D VR; orthogonal/curved multiplanar reformation). Results and Discussion Three‐dimensional and multiplanar studies of the singular canal of Morgagni morphology were possible with appropriate thresholding. The topographical correlations between the posterior ampullary nerve, posterior semicircular canal and the round window were evaluated. The level of the nerve in comparison with the round window may vary. Three types of positions are described. Type 1 is the lowest position: the nerve is located under the inferior part of the scala tympani. Type 3 is the highest position: the nerve is located higher than the superior part of the round window (this type goes straight from the internal auditory canal to the posterior ampulla). Type 2 is an intermediate form. Difficulty level in singular neurectomy depends on the course of the singular nerve. Type 1 is the easiest to operate on with the lowest risk, whereas type 2 and particularly type 3 are riskier in terms of damage to the round window membrane. Conclusion 3D reconstructions using high resolution X‐ray micro‐tomography aid comprehension of posterior ampullary nerve complex anatomy. Transtympanal posterior ampullary neurectomy can be performed only in selective cases. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".