Within the Temporal Bone · Chapter 17 · Part V · Completion
Completion, Complications and Transfer to the Theatre
Finish the bone honestly; carry only what it taught
Bench mode: one step per screen, large type, screen kept awake. Tap, use the arrow keys or say “next”.
- Specimen
- Any completed dissection, still on the holder
- Bench time
- The end of every session, before the bone is put away
- Burrs
- None: blunt probe, camera, record sheet
- View
- Low power for the whole field, then higher
- Before this
- Any dissection chapter
By the end you can
- Inspect the finished field in a fixed order
- Separate intended removal from unintended damage
- Respond to a breach so that its cause can be found, and choose a targeted repeat
- Write a record that distinguishes finding from interpretation
- Agree your role before taking a laboratory skill into the theatre
A record another surgeon could check against the specimen and its photographs: achieved, preserved, uncertain and next exercise.
This chapter does not prescribe a rescue sequence for a live injury. A bench breach is recorded and its mechanism named; it is not used to improvise a clinical repair.
The landmark chain
Each landmark leads to the next. Tap any one to see every station where it appears.
17.1 Inspect the result
A dissection is not finished when the drill stops. It is finished when the field has been inspected, every structure placed at risk has been accounted for, and the record says plainly what was achieved, what was preserved, what remains uncertain and what should be practised next. This chapter applies to every exercise in the bench companion.
At the end of any dissection, return to a broad view. Clear loose debris, restore orientation and review the objective you set. A structure outside the final photograph still has to be accounted for if it was placed at risk.
Describe a structure as preserved only to the extent that you have actually assessed it.
| Preserved means | Preserved does not mean |
|---|---|
| The structure was seen and assessed | Out of sight, so assumed intact |
| Its covering is intact, or its exposure intended | Visually continuous, so assumed to function |
| The assessment is stated: covered, exposed, thinned | Hearing or balance kept: a specimen cannot show it |
17.2 · The 3 stations
Inspect the completed field
- Restore orientation: side, superior, anterior. Clear debris and dry the field.
- Inspect in a fixed order, as relevant to the procedure: tegmen, sinus covering, posterior canal wall or altered cavity, ossicular chain, labyrinthine boundary, facial nerve region, any opened recess.
- For each, state what you see: intact, thinned, exposed, opened. If a covering is intact but the nerve beneath was not exposed, say exactly that.
- Photograph the field with orientation and stage labels.
Every structure at risk accounted for in words, not only in the photograph.
You are about to write “preserved” for a structure you did not inspect.
Respond to a breach
- Stop the causative movement and obtain instructor review.
- Keep the field as it is long enough to identify the structure, the extent and the likely mechanism; continuing to drill destroys the evidence.
- Name the likely mechanism: poor orientation, inadequate exposure, force, instrument contact, heat or an unrecognised variant.
- A dural opening, sinus injury, labyrinthine fistula, footplate displacement and facial nerve injury each mean something different in a patient. Record the bench finding; do not improvise a rescue from it.
Structure, extent, stage and mechanism recorded and reviewed with the instructor.
The plan is to drill on and repeat the whole operation. Find the mechanism first.
Record and transfer
- Write a short account: specimen, procedure, preserved anatomy, intentional resections, unintended changes and instructor feedback.
- Distinguish what you observed from your interpretation of it; do not let hindsight make an uncertain step look certain.
- End with four specific statements: achieved, preserved, uncertain, next exercise.
- Before any related work in a patient, add what the laboratory cannot supply, and agree your role with the supervising surgeon.
A record another surgeon could check against the specimen and its photographs.
The record says only “dissection completed”.
▶ Internal Carotid Artery Control: Lateral skull base tumour
Opens on YouTube (needs internet). From laboratory to theatre: anatomy learned at the bench, applied with indication, team and supervision.17.3 When a boundary is breached
Stop, preserve, identify and name the mechanism; then choose the repeat that corrects it. Repeating the whole operation unchanged reproduces the same error, only faster.
17.4 In the theatre the injury is different
In live surgery, immediate control, senior assistance, functional assessment and an appropriate repair or escalation plan depend on the injury and the clinical circumstances. They cannot be reduced to a single repair instruction, and this companion does not prescribe a rescue sequence from a cadaveric finding. In the laboratory, an error should prompt a targeted repeat: if the cause was an unrecognised boundary, repeat its identification and exposure on another region or specimen; if it was an unstable hand, return to instrument control.
17.5 Evaluate the process, not only the cavity
Review preparation, orientation, instrument handling, preservation, recognition of difficulty and the final anatomy. A clean-looking endpoint may have been reached with repeated unsafe contacts. An exposure stopped appropriately short of its target may show sound recognition of a limit. Discuss both the process and the result.
Use validated assessment tools where they are available and suited to your programme. Do not invent a pass mark or a minimum number of bones and present it as proof of competence. Record time for context, but speed alone does not define proficiency. The instructor should name the skills that are established and those that need more supervised practice.
17.6 Transfer to the patient
A familiar route may behave differently in diseased, scarred or previously operated tissue. Before clinical surgery, add the indication, the patient's priorities, hearing, vestibular and facial nerve function, infection or tumour extent, imaging, anaesthetic considerations, team preparation, consent and postoperative care.
Agree with the supervising surgeon which steps you may undertake, the circumstances that require a pause and how you will ask for help. Direct supervision remains important when technical familiarity exceeds clinical experience: knowing how to expose a structure does not establish when it should be exposed in a patient.
17.7 Fault finding
| What you see | Probable cause | Correction |
|---|---|---|
| Clean cavity reached with repeated unsafe contacts | Only the endpoint judged | Review the process as well as the result |
| Appropriately stopped exposure marked as failure | Recognition of a limit not credited | Credit the stop; record the limit |
| Record makes every step look certain | Retrospective description | Separate observation from interpretation |
| Speed quoted as proof of skill | Wrong measure | Record time for context only |
| Theatre plan copied from the bench | Clinical elements missing | Add indication, function, disease, consent and supervision |
17.8 Viva at the bench
What does “preserved” mean in your record, and what does it not mean?
That the structure was seen and assessed and its covering is intact or its exposure intended, with the state stated. It does not mean out of sight and assumed intact, nor that function such as hearing or balance was kept.
Why can an appropriately stopped incomplete exposure be educationally valuable?
It shows recognition of a limit: the judgement to stop is a skill the theatre needs, and it should be credited and recorded rather than marked as failure.
What must be added before a laboratory skill is used in a patient?
The indication, the patient's priorities, hearing, vestibular and facial function, disease extent, imaging, anaesthesia, team preparation, consent, postoperative care, and an agreed role with the supervising surgeon.
One best answer
17.9 My dissection log
Saved on this device only. Print it or send the summary to your fellowship coordinator for review.
Score the dissection · review order
| Item | 0 · not achieved | 1 · partly | 2 · achieved |
|---|---|---|---|
| Field inspected in a fixed order | |||
| Each structure at risk stated: intact, thinned, exposed, opened | |||
| Any breach recorded with structure, extent, stage and mechanism | |||
| Targeted repeat chosen for each error | |||
| Observation separated from interpretation | |||
| Achieved, preserved, uncertain and next exercise written |
The review order is a teaching method, not a validated scoring instrument. Structured end-product scales such as the Welling scale have been studied for rater reliability; they assess the dissection, not operative outcome, but they make feedback specific.
Before you take a laboratory skill into the theatre
Sources and credits
- Butler NN, Wiet GJ. Reliability of the Welling scale (WS1) for rating temporal bone dissection performance. Laryngoscope 2007;117:1803–8. doi.org/10.1097/MLG.0b013e31811edd7a
- Zirkle M, Taplin MA, Anthony R, Dubrowski A. Objective assessment of temporal bone drilling skills. Ann Otol Rhinol Laryngol 2007;116:793–8. doi.org/10.1177/000348940711601101
Real dissection photographs with numbered drawings: Bassett Collection, Stanford University (CC BY-SA 4.0). Classic anatomical and operative plates: Gray’s Anatomy of the Human Body (1918, drawings by H. V. Carter) and Burghard’s A System of Operative Surgery (1909), both public domain, credited beside each plate. Remaining diagrams and charts: Dr Bhushan Kathuria & Team, not to scale. Operating-theatre frames and clips: our theatre, patient consent taken, identity not shown. Atlas photographs: Open Access Atlas of Otolaryngology (CC BY-NC 3.0), with their authors credited beside each image. This edition uses no AI-generated images. For professional education alongside supervised instruction and local protocols.
Dr Bhushan Kathuria & Team · Reg. No. HN-017323, Haryana Medical Council · A GeNext MedEd Foundation surgical education initiative.
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