1. Temporal Bone Dissection Criteria

We are using the temporal bone surgical simulator as a potential device to objectively assess performance on a basic mastiodectomy. As we work towards creating automated metrics to quantitatively evaluate surgical performance, we would like to first determine which metrics are considered the most important and relevant in the assessment of a temporal bone dissection. You will need approximately 15 minutes to complete this survey. Please address any concerns or questions under 'Comments' listed under each section.

The following list of metrics is compiled from temporal bone dissection criteria published by the University of Toronto, Stanford, and the Ohio State University (references cited below).

* 1. Cortex

  Very Important Important Moderately Important Of Little Importance Unimportant
Complete saucerization
Appropriate depth of cavity
Straightness of edges

* 2. Tegmen/Dura

  Very Important Important Moderately Important Of Little Importance Unimportant
No holes in the tegmen
Drill force reduced significantly within 4mm of dura
Drill velocity slowed within 4mm of dura
Use of diamond burr within 2mm of dura
No cells remain on tegmen

* 3. Sigmoid Sinus

  Very Important Important Moderately Important Of Little Importance Unimportant
Sigmoid sinus is not entered
Drill force reduced significantly within 4mm of sigmoid
Drill velocity slowed within 4mm of sigmoid
Use of diamond burr within 2mm of signmoid
Sigmoid sinus completely exposed

* 4. Facial Nerve

  Very Important Important Moderately Important Of Little Importance Unimportant
No violation of nerve sheath
Drill force significantly reduced within 4mm of facial nerve
Drill velocity slowed within 4mm of facial nerve
Use of diamond burr within 2mm of facial nerve
Facial recess completely exposed (overlying bone sufficiently thinned so nerve can be seen, located, and safely avoided)

* 5. Semicircular Canals

  Very Important Important Moderately Important Of Little Importance Unimportant
Semicircular canals blue lined without fenestra
Horizontal semicircular canal skeletonized
Superior semicircular canal skeletonized
Posterior semicircular canal skeletonized
Drill force significantly reduced within 4mm of semicircular canals
Drill velocity slowed within 4mm of semicircular canals
Use of diamond burr within 2mm of semicircular canals

* 6. External Auditory Canal

  Very Important Important Moderately Important Of Little Importance Unimportant
Canal wall up
No holes in the EAC
No cells remain on EAC
Posterior canal wall thinned

* 7. Sinodural Angle

  Very Important Important Moderately Important Of Little Importance Unimportant
No cells remain on sinodural angle
Sinodural angle sharply defined

* 8. Other

  Very Important Important Moderately Important Of Little Importance Unimportant
Antrum entered
Does not drill on ossicle
Skeletonization of jugular bulb
Stapedial muscle dissected

* 9. Procedural/Drilling Technique

  Very Important Important Moderately Important Of Little Importance Unimportant
Maintains visibility while removing bone
Selects appropriate burr type and size -Drills with smooth and deliberate strokes
Drills with broad strokes
Drills with unidirectional strokes
Drills in best direction (clear understanding of cutting edge)
Low frequency of drill 'jumps' (drill 'jump' defined as when one drills >1cm away from the previously removed bone)
Firm, low, good hand position and grip on drill
Maintains appropriate distance between drill and suction (<2cm apart)
Does not use excessive drill force near critical structures to prevent popping through bone and harming underlying structures
Does not use excessive drill velocity near critical structures to prevent loss of control
Total time on task <30 min

* 10. Cognitive

  Very Important Important Moderately Important Of Little Importance Unimportant
Identifies the facial nerve at the stylomastoid foramen
Identifies the facial nerve at the external genu
Identifies tympanic segment of the facial nerve
Identifies the facial nerve at the cochlearform process
Identifies the chorda tympani or stump
Identifies the carotid artery in middle ear
Identifies the jugular bulb
Identifies the endolymphatic sac transition to duct
Identifies the digastric ridge
Digastric tendon followed to stylomastoid foramen
References
Butler NN, Wiet GJ. Reliability of the Welling scale (WS1) for rating temporal bone dissection performance. Laryngoscope 2007 Oct; 117(10):1803-8.

Sewell C, Morris D, Blevins N, Barbagli F, Salisbury K. Medicine Meets Virtual Reality 13. James D. Westwood et al. (Eds.). IOS Press, 2005.

Sewell C, Morris D, Blevins NH, Agrawal S, Dutta S, Barbagli F, Salisbury K. Validating Metrics for a Mastoidectomy Simulator. Medicine Meets Virtual Reality 15. J.D. Westwood et al. (Eds.). IOS Press, 2007.

Zirkle M, Taplin MA, Anthony R, Dubrowski A. Objective Assessment of Temporal Bone Drilling Skills. Annals of Otology, Rhinology & Laryngology 2007. 116(11):793-798.

T