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Transitioning to endoscopic Type 1 tympanoplasty: a single-centre retrospective analysis of competence, outcomes, and operative delegation to guide departmental adoption

This single-center retrospective study demonstrates that an experienced microscopic surgeon can achieve competence in endoscopic Type 1 tympanoplasty after approximately 24 cases while maintaining hearing and safety outcomes, providing a realistic framework for safely delegating operative responsibility during departmental adoption.

Original authors: Antoni D. Gardener, Andreas Espehana, Max Whittaker

Published 2026-08-06

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Antoni D. Gardener, Andreas Espehana, Max Whittaker

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine the human ear as a tiny, intricate concert hall. The star performer is the eardrum, a delicate drumskin that vibrates to catch sound waves and pass them along to the inner ear. But sometimes, this drumskin gets a hole in it—a perforation—often due to infections or accidents. When that happens, the music gets muffled, and the ear becomes vulnerable to water and germs. For decades, the standard way to fix this "broken drum" was to use a microscope. Surgeons would make a small cut behind the ear, peel back the skin, and use two hands to carefully patch the hole with a piece of tissue. It worked well, but it was like repairing a watch through a heavy, bulky window: you could see the gears, but you couldn't see the tiny, tricky corners hidden in the back.

In recent years, doctors have started using a different tool: a tiny, rigid camera called an endoscope. Think of this as a high-definition flashlight on a stick that you can slide right through the ear canal. It offers a wide-angle, zoomed-in view of the entire drum, even the sneaky corners that the microscope misses, without needing a cut behind the ear. This sounds amazing, but it comes with a catch. Using a microscope is like driving a car with two hands on the wheel; using an endoscope is like driving with one hand on the wheel and the other holding the camera. It's a totally different skill set. The big question for hospitals and surgeons isn't just "Does the camera work?" but "How long does it take a surgeon to get good at this one-handed dance, and can they teach it to others without breaking the drum?"

This paper tells the story of one surgeon in London who decided to switch from the old two-handed microscope style to the new one-handed endoscopic style. The researchers wanted to map out the "learning curve"—that bumpy road between being a beginner and a master. They looked at 124 surgeries performed between 2018 and 2025. They split the endoscopic surgeries into three groups: the early days, the middle, and the late stage. They also checked if the surgeon could safely let a second person help with the operation as they got more comfortable, and they compared the results to the surgeon's own past work with microscopes.

Here is what they found. First, the surgeon didn't get faster. You might expect that as you learn a new trick, you do it quicker, but the time it took to finish the surgery stayed roughly the same, averaging about 63 minutes, whether it was the first case or the hundredth. This makes sense because the surgeon was already an expert with the microscope; they just had to learn a new way of holding the tools, not how to fix the ear itself.

Second, the "learning curve" was real, but it had a specific shape. The researchers used a special math tool called a CUSUM chart to track the success rate. They found that for the first 24 cases, the success rate (how often the hole was completely sealed) was a bit shaky, sitting around 58%. But after the 24th surgery, something clicked. The success rate jumped up to 88% and stayed there. It wasn't a slow, gradual climb; it was a distinct turning point where the surgeon moved from "learning" to "proficient."

Third, and perhaps most importantly for hospitals, the surgeon could safely share the work. As the surgeon got more confident, they started letting other doctors (second surgeons) help them, and eventually, take the lead on parts of the operation. In the middle phase of the study, 60% of the surgeries involved a second surgeon. The scary part? It didn't matter. The success rate and hearing improvements were exactly the same whether the main surgeon did it alone or with a partner. The "teaching" didn't hurt the patients.

Finally, when they compared the new endoscopic method to the old microscopic method, the results were very similar. Once the surgeon passed that 24-case learning hurdle, the endoscopic success rate (88%) was almost as good as the microscopic rate (94%). The hearing gains were also consistent, improving by about 6 to 9 decibels in both groups.

So, what's the takeaway? If a hospital wants to switch to this modern, less invasive way of fixing eardrums, they shouldn't expect the surgeon to get faster immediately. Instead, they should expect a learning period of about 24 surgeries where the success rate climbs from about 58% to 88%. After that point, the surgeon is a pro, and they can safely start teaching others or sharing the work without worrying about the patient's outcome. It's a realistic roadmap for a department to say, "We can do this, and here's exactly how long it will take to get it right."

Technical Summary: Transitioning to Endoscopic Type 1 Tympanoplasty

Problem Statement
Departments adopting endoscopic ear surgery require realistic, evidence-based expectations regarding the development of surgical competence, the timeline for achieving stable outcomes, and the safe delegation of operative responsibility during the transition. While systematic reviews suggest endoscopic Type 1 tympanoplasty yields outcomes comparable to traditional microscopic approaches, there is a scarcity of single-surgeon data detailing the transition as a staged process. Specifically, there is a lack of granular analyses that model how a surgeon proficient in microscopic techniques acquires endoscopic competence, how outcomes evolve during this learning curve, and how operative responsibility can be safely shared with second surgeons without compromising patient care.

Methodology
This study is a single-centre, retrospective observational cohort study conducted at Homerton University Hospital (London, UK) between 2018 and 2025. It analyzed 124 Type 1 tympanoplasties performed by a single consultant otologist, comprising 106 endoscopic cases and 18 microscopic cases (serving as a contemporaneous benchmark).

Study Groups: Endoscopic cases were ordered chronologically and divided into three prespecified phases (early, mid, late) of approximately equal size.
Data Collection: Data were extracted from theatre management systems, operative notes, and audiology reports. Key variables included operative time, graft closure rates, air-bone gap (ABG) improvement, complication rates, and the involvement of a second surgeon.
Statistical Analysis:
- Primary Analysis: Pre-specified comparisons of operative time, closure rates, and ABG improvement across the three endoscopic phases using ANOVA and chi-square tests.
- Exploratory Post Hoc Analysis: A Cumulative Sum (CUSUM) analysis was performed to identify the specific turning point in the learning curve where performance stabilized. Binary logistic regression was used to model the odds of successful graft closure against the chronological case number.
- Benchmarking: Endoscopic outcomes were compared against the surgeon's microscopic cases performed over the same period.

Key Results

Competence Acquisition (Learning Curve): The prespecified comparison of closure rates across the three phases was not statistically significant ( $p=0.215$ ). However, CUSUM analysis identified a distinct turning point at the 24th case. Before this point, the closure rate was 58% (14/24); after this point, it rose to 88% (65/74). Logistic regression supported this trend, showing an odds ratio of 1.20 for success per 10 additional cases ( $95\%$ CI 0.99–1.45, $p=0.058$ ).
Operative Time: Contrary to typical learning curve expectations, mean operative time did not significantly shorten across the phases ( $p=0.144$ ). The mean time remained stable at approximately 63–68 minutes for endoscopic cases, comparable to the microscopic benchmark (69.4 minutes, $p=0.263$ ).
Clinical Outcomes:
- Closure Rate: The overall endoscopic closure rate was 80.6% (79/98), compared to 94.1% (16/17) for microscopic cases ( $p=0.30$ ). When isolating the post-turning-point endoscopic cases, the rate was 88%, which was not significantly different from the microscopic benchmark ( $p=0.681$ ).
- Hearing: Mean ABG improvement was maintained across phases (approximately 6–9 dB) and did not differ significantly ( $p=0.825$ ).
- Safety: The overall complication rate was 8.5% (9/106), with no cases of sensorineural hearing loss or facial nerve palsy.
Operative Delegation: The involvement of a second surgeon increased from 2.8% in the early phase to a peak of 60.0% in the mid-phase, then decreased to 34.3% in the late phase. Crucially, cases involving a second surgeon did not differ significantly in closure rate ( $p=0.284$ ) or hearing outcomes ( $p=0.875$ ) compared to those performed by the consultant alone.

Key Contributions

Characterization of the Learning Curve: The study provides a realistic, competency-based framework for the transition to endoscopic tympanoplasty, identifying that for an experienced microscopic surgeon, competence (defined by stable closure rates) is achieved after approximately 24 cases.
Decoupling Time from Competence: The findings challenge the assumption that a learning curve must be marked by a reduction in operative time. For surgeons already proficient in microscopic otology, efficiency is present from the outset; the marker of successful adoption is the maintenance of outcomes while gradually increasing operative delegation.
Safe Delegation Model: The paper demonstrates that operative responsibility can be progressively shared with second surgeons of varying grades (from trainees to other consultants) without compromising graft success or hearing outcomes, even during the consolidation of the primary surgeon's endoscopic skills.
Benchmarking: It establishes that once the initial learning phase is passed, endoscopic outcomes (88% closure rate) are practically comparable to the surgeon's established microscopic benchmark.

Significance and Claims
The authors claim that these findings offer a "realistic, competency-based framework" for departments planning a transition to endoscopic Type 1 tympanoplasty. The study suggests that departments should anticipate:

A consolidation of competence on outcome measures after roughly 20–25 cases.
Stable operative times that do not necessarily decrease for microscope-trained surgeons.
The ability to maintain hearing and safety outcomes from the very beginning of the series.
A safe trajectory for sharing operative responsibility, where the pattern of delegation itself serves as a teaching tool.

The authors explicitly state that these are exploratory findings that should be confirmed prospectively. They emphasize that the study describes a single-surgeon experience in a district general hospital, limiting generalizability, but provides a pragmatic model for understanding the transition process. The primary significance lies in shifting the focus from "time-based" learning curves to "outcome-based" competence and safe delegation strategies.

Technical Summary: Transitioning to Endoscopic Type 1 Tympanoplasty

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