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Errors in the assessment of tympanic membrane perforations
1University Department of Otolaryngology, Ninewells Hospital, Dundee, UK.
Abstract:
It is commonly stated that operative closure of large perforations of the tympanic membrane is less successful than closure of small perforations. Few authors mention the exact size of the perforations studied, and fewer still give their method of measuring perforations. We describe a photographic method of assessing the size of perforations relative to the total drumhead, measuring them with a computerized digitizing pad. Thirteen temporal bones were selected at random. Perforations of different sizes, shapes and at different sites were fashioned in the tympanic membranes. These were assessed by clinicians of all grades, who were asked to draw the perforations and give estimates of the perforation size as a percentage of the total drumhead. Visual estimates and drawings were compared with a photographic objective method. Gross errors (some in excess of 100%) were apparent in both estimates and drawings. There was a highly significant statistical difference between the objective method and visual estimates and drawings (P < 0.001). Greater clinical experience was not correlated with better performance in estimating the size of perforations.
Insights
Estimating tympanic membrane perforation size is inaccurate. A new photographic method offers objective measurement, revealing significant errors in visual assessments by clinicians, regardless of experience.
Area of Science:
- Otolaryngology
- Medical Imaging
- Surgical Outcomes
Background:
- Operative closure success for tympanic membrane perforations is often linked to size.
- Accurate measurement of perforation size is crucial for evaluating surgical outcomes.
- Current methods for assessing perforation size lack standardization and objective validation.
Purpose of the Study:
- To introduce and validate a precise photographic method for measuring tympanic membrane perforation size.
- To compare the accuracy of this objective method against subjective visual estimates by clinicians.
Main Methods:
- A photographic technique using a computerized digitizing pad was developed to measure perforation size relative to the total tympanic membrane area.
- Thirteen temporal bones with artificially created perforations of varying sizes, shapes, and locations were used.
- Clinicians of all grades visually estimated and drew perforations, which were then compared to objective measurements.
Main Results:
- Visual estimates and drawings demonstrated significant inaccuracies, with errors exceeding 100% in some cases.
- A highly significant statistical difference (P < 0.001) was found between objective photographic measurements and subjective visual assessments.
- Clinical experience did not correlate with improved accuracy in estimating perforation size.
Conclusions:
- Subjective visual estimation of tympanic membrane perforation size is unreliable.
- The described photographic method provides an objective and accurate means for assessing perforation size.
- Standardized, objective measurement is essential for reliable evaluation of tympanic membrane repair outcomes.