Outcomes in stapedotomy surgery: the learning curve redefined

Objective: The aim of this study is to determine if the cumulative summation test for the learning curve (LC-CUSUM) and the cumulative summation graph (CUSUM) can be used to demonstrate landmark points of competence and maintenance of proficiency in stapes surgery over a continuous time period.

Study Design: Retrospective review from January 1999 until August 2014.

Setting: Tertiary referral hospital.

Patients: All adult patients with confirmed otosclerosis.

Intervention(s): Two-hundred and four primary and revision stapedotomy.

Main Outcome Measure(s): Learning curves were constructed using the CUSUM and LC-CUSUM. Failure was defined as closure of the ABG >10dB in less than 10% of patients to demonstrate the landmark point of competency and to highlight any fluctuations over a prolonged period.

Results: When the failure rate was defined as closure of the ABG >10dB, it was not possible to create useful LC-CUSUM and CUSUM graphs, but by redefining the failure rate as > 15 dB, competency was reached at case 43 and maintained with natural fluctuations occurring between cases 137 and 149 and again at case 196.

Conclusions: LC-CUSUM and CUSUM are a more robust analytical method of illustrating the learning curve and suggest that the traditional benchmark of closure of the ABG 10 dB in more than 90% of patients may need reconsideration. It can also be used as standardized audit tools when monitoring results and used to plan future training programs as they clearly define a point when novice trainees become competent.