TABLE I.
Survey Results—Temporal Bone Dissection (Mastoidectomy With Facial Recess Approach) Grading Criteria With Ranked Importance.
|
Criteria to Be Included in the New Cross-Institutional Scale* |
% Participants That Ranked Criterion as “Very Important” or “Important” |
Criteria to Be Excluded From the New Cross-Institutional Scale† |
% Participants That Ranked Criterion as “Very Important” or “Important” |
|---|---|---|---|
| Maintains visibility while removing bone | 100 | Drill force reduced within 4 mm of facial nerve | 69.8 |
| Selects appropriate burr type and size | 98.9 | Identifies the digastric ridge | 69.4 |
| Antrum entered | 97.9 | Horizontal SCC skeletonized | 69.4 |
| No violation of facial nerve sheath | 97.7 | Maintains appropriate distance between drill and suction | 66.3 |
| Sigmoid sinus is not entered | 96.5 | Does not use excessive drill velocity near critical structures | 64.7 |
| Identifies tympanic segment of the facial nerve | 96.5 | Sinodural angle sharply defined | 64.7 |
| Does not drill on ossicle | 93.1 | No cells remain on EAC | 63.8 |
| Does not use excessive drill force near critical structures | 93 | Identifies the jugular bulb | 62.8 |
| Firm, low, good hand position and grip on drill | 91.9 | Drill force reduced within 4 mm of dura | 62.3 |
| Identifies the chorda tympani or stump | 90.7 | Identifies the facial nerve at the stylomastoid foramen | 60.7 |
| Drills with broad strokes | 88.5 | Digastric tendon followed to stylomastoid foramen | 58.2 |
| Drills in best direction (clear understanding of cutting edge) | 88.4 | Identifies the carotid artery in middle ear | 58.1 |
| Identifies the facial nerve at the cochle-ariform process | 88.3 | No cells remain on tegmen | 57 |
| Appropriate depth of cavity (cortex) | 86 | Drill force reduced within 4 mm of sigmoid | 56.5 |
| Canal wall up (EAC) | 85.6 | Drills with unidirectional strokes | 55.9 |
| No holes in the EAC | 84.9 | Identifies the endolymphatic sac transition to duct | 53 |
| Complete saucerization (cortex) | 83 | SCCs blue-lined without fenestra | 45.8 |
| Posterior canal wall thinned | 82.4 | Use of diamond burr within 2 mm of dura | 45.4 |
| Low frequency of drill ‘jumps’ (‘jump’ defined as drilling further than 1cm from previous spot) | 81.6 | Use of diamond burr within 2 mm of sigmoid | 42 |
| Identifies the facial nerve at the external genu | 80.9 | Posterior SCC skeletonized | 41.6 |
| Facial recess completely exposed (overlying bone sufficiently thinned so nerve can be seen, located, and safely avoided) | 75.9 | Total time on task <30 min | 40.4 |
| No holes in tegmen | 75.6 | Drill velocity slowed within 4 mm of facial nerve | 37.2 |
| Use of diamond burr within 2mm of facial nerve | 74.5 | Superior SCC skeletonized | 36.5 |
| No cells remain on sinodural angle | 71.8 | Use of diamond burr within 2 mm of SCCs | 34.1 |
| Drill force reduced within 4 mm of SCCs | 30.5 | ||
| Sigmoid sinus completely exposed | 25.7 | ||
| Drill velocity slowed within 4 mm of dura | 23.5 | ||
| Drill velocity slowed within 4 mm of sigmoid | 23.2 | ||
| Skeletonization of jugular bulb | 23 | ||
| Drill velocity slowed within 4 mm of SCCs | 22.1 | ||
| Straightness of edges (cortex) | 19.3 | ||
| Stapedial muscle dissected | 10.3 |
*
Ranked by >70% participants as “very important” or “important.”
†
Ranked by <70% participants as “very important” or “important.”
SCC = semicircular canal; EAC = external auditory canal.