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Virtual reality surgical simulation of mastoidectomy is a promising training tool for novices. Final-product analysis for assessing novice mastoidectomy performance could be limited by a peak or ceiling effect. These may be countered by simulator-integrated tutoring.
Twenty-two participants completed a single session of self-directed practice of the mastoidectomy procedure in a virtual reality simulator. Participants were randomised for additional simulator-integrated tutoring. Performances were assessed at 10-minute intervals using final-product analysis.
In all, 45.5 per cent of participants peaked before the 60-minute time limit. None of the participants achieved the maximum score, suggesting a ceiling effect. The tutored group performed better than the non-tutored group but tutoring did not eliminate the peak or ceiling effects.
Timing and adequate instruction is important when using final-product analysis to assess novice mastoidectomy performance. Improved real-time feedback and tutoring could address the limitations of final product based assessment.
To determine the rate of spontaneous tumour shrinkage in a group of patients with sporadic vestibular schwannoma managed with a ‘wait and scan’ approach.
All patients with a unilateral cerebello-pontine angle tumour resembling a vestibular schwannoma were registered prospectively in a national database in Denmark. Patients registered with tumour shrinkage were identified and all computed tomography and magnetic resonance imaging scans retrieved, re-evaluated and related to the clinical data.
Of 1261 observed patients, 48 displayed spontaneous shrinkage (3.81 per cent). Mean absolute shrinkage was 6.25 mm, equivalent to 52.1 per cent. Absolute shrinkage correlated with tumour size and follow-up period, whereas relative shrinkage was significantly greater for tumours which were purely intrameatal at diagnosis. There was no correlation between age and the degree of shrinkage.
Four per cent of sporadic vestibular schwannomas shrink spontaneously. These findings substantiate the ‘wait and scan’ strategy for tumours with a largest extrameatal diameter of up to 20 mm.
To evaluate residual tumour occurrence after vestibular schwannoma surgery, based on intra-operative registration and magnetic resonance imaging one year post-operatively.
Patients undergoing translabyrinthine surgery for vestibular schwannoma in Denmark between 1976 and 2008 were registered in a national database covering 5.5 million inhabitants.
Translabyrinthine surgery was undertaken on 1143 patients. Of these, 978 had total, 140 near-total and 25 subtotal tumour excision, as assessed intra-operatively by the surgeon. One year after surgery, 65 per cent of small tumour remnants and 11 per cent of large tumour remnants were not visible on magnetic resonance imaging. The mean pre-operative size was significantly smaller for totally excised tumours, compared with near-totally and subtotally excised tumours. Revision surgery was performed for 14 patients (1.2 per cent), of whom 2 had received total, 5 near-total and 6 subtotal excisions initially.
Most residual tumours disappear spontaneously, probably due to devascularisation. Few patients with a small residual vestibular schwannoma will require revision surgery or secondary radiotherapy.
This study aimed to evaluate the predictive value of both hearing level (at various frequencies) and speech discrimination for forecasting hearing outcome after a period of observation, in patients with vestibular schwannoma.
Over a 33-year period, 1144 patients with vestibular schwannoma were allocated to ‘wait and scan’ management, with annual magnetic resonance imaging and audiological examination. Two complete pure tone and speech discrimination audiograms were available for 932 patients.
The predictive value of initial hearing level better than 10 dB for forecasting hearing outcome after observation increased from 59 per cent at 250 Hz to 94 percent at 4000 Hz. At diagnosis, hearing level of 10 dB or better at 4000 Hz was found in only 18 of the 932 VS ears, while good speech discrimination was found in 159 patients (17 per cent). Of the latter patients, 138 maintained good hearing after observation.
In vestibular schwannoma patients, good high frequency hearing and good speech discrimination at diagnosis are useful tools in predicting good hearing after observation.
To evaluate hearing changes during ‘wait and scan’ management of patients with vestibular schwannoma.
Over a 10-year period, 636 patients have prospectively been allocated to ‘wait and scan’ management, with annual magnetic resonance scanning and audiological examination.
At the time of diagnosis, 334 patients (53 per cent) had good hearing and speech discrimination of better than 70 per cent; at the end of the 10-year observation period, this latter percentage was 31 per cent. In 17 per cent of the patients, speech discrimination at diagnosis was 100 per cent; of these, 88 per cent still had good hearing at the end of the observation period. However, in patients with even a small initial speech discrimination loss, only 55 per cent maintained good hearing at the end of the observation period.
After comparing the hearing results of hearing preservation surgery and of radiation therapy with those of ‘wait and scan’ management, it appears that, in vestibular schwannoma patients with a small tumour and normal speech discrimination, the main indication for active treatment should be established tumour growth.
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