Surgeon perspectives of three-dimensional endoscopy in paediatric otolaryngology: A qualitative study

above findings encourage the continued use of 3D endoscopy, particularly in Paediatric Otolaryngology airway surgery.

Three-dimensional (3D) endoscopy has emerged as a surgical tool to improve visualisation and stereoscopic vision in Otolaryngologic surgery.The diameter of 3D endoscopes has been reduced to 4 mm, thereby allowing surgeons to better navigate narrow anatomy while continuing to reliably provide images of high quality and resolution.
Early peer-reviewed evaluations of the novel surgical technique have not yielded a definitive consensus on 3D endoscopy's utility in Otolaryngology.Three-dimensional endoscopy was found to provide enhanced visualisation of the laryngeal structures which improved surgical excision. 1In contrast, other reports have found no difference in clinical outcomes when using 3D over 2D endoscopy in sinus or middle ear surgeries, although 3D endoscopy provided notably improved anatomic visualisation. 2,3Despite the discordance, such quantitative research has been confined to experimental settings or specific clinical presentations, and has largely failed to evaluate 3D endoscopy use in regular clinical practice.This is the first study to use a qualitative methodology to assess the potential advantages and disadvantages of 3D endoscope use in paediatric Otolaryngology surgery as experienced by surgeons with regular access to 3D endoscopic technology.

| MATERIALS AND METHODS
A qualitative study design was employed to obtain an in-depth and broad understanding of Otolaryngologists' experiences with 3D endoscopy, focussing on clinical advantages and challenges that they faced when using the novel surgical equipment.A Karl Storz TipCam™ (Karl Storz GmbH & Co, Tuttlingen, Germany) second generation 3Dhigh-definition, 4 mm endoscopy system (0, 30, and 45 degree) was used by all participants with 3D glasses and appropriate personal protective equipment.The 3D endoscopic system setup is provided in Figure 1.The study was approved by the Research Ethic Board at British Columbia Children's Hospital (BCCH).Written informed consent was obtained from all interview participants prior to their study participation.The study followed Standards for Reporting Qualitative Research (SRGR) guidelines.

| Participants
The primary author, with guidance from the research team, conducted structured interviews with six Otolaryngologists operating at BCCH.The participating surgeons included four senior consultants and two surgical fellows.The sample size was limited due to the number of surgeons who had regular access and experience with the 3D endoscopy equipment.Previous research has demonstrated that a qualitative sample size is best determined by the nature of individual study rather than a power calculation. 4-6

| Procedure
The structured interviews for qualitative data collection were conducted over Zoom™ (Zoom Video Communication Inc., San Jose, CA), recorded, and transcribed for research purposes.The open-ended questions were prepared in advance and were consistent across all participants (Table A1).The questions were prepared to encompass varied and clinically relevant components 3D endoscopic surgery.Moreover, particular attention was paid to contrast 3D endoscopy to conventional surgical technology, including 2D endoscopy and the surgical microscope.

| Data analysis
The authors analysed the interviews for recurrent themes once all interviews were completed.The interview responses were compiled and examined through modified thematic analysis using open and axial coding.The data coding was independently reviewed and interpreted by three authors to mitigate any individual bias.The same three authors used their experience in grounded theory whereby the use of open coding allowed for the deconstruction of information into common groups based on shared ideas, and axial coding organised this data into overarching themes. 7Due to our novel research methodology on this topic, the aim was exploratory to elucidate original and recurrent themes.
All six surgeons invited to participate in the study completed full interviews.Five of the six participants were male (83%).All surgeons had at minimum 1 year of experience with the 3D endoscopy system, wherein the system was used for laryngeal, ear, and sinus surgery.The interviewed surgeons drew on a combined surgical experience of greater than 100 cases with the 3D endoscopic system, approximately half of which were airway surgeries.

| Thematic analysis
Seven over-arching themes were identified from the data and categorised into advantages or disadvantages of the 3D endoscopy system, or additional themes, as described in Table 1.The identified themes are discussed in more detail as follows.
Improved stereoscopic vision when using 3D endoscopy was a recurring point of discussion for all six participants.When using a 2D scope, Moreover, 3D endoscopy was found to be a valuable teaching tool due the more detailed visualisation of anatomical structures.

Key points
1.This is the first study to use a qualitative methodology to assess the potential advantages and disadvantages of the application of 3D endoscopes in paediatric otolaryngology surgery.
2. Open-ended, structured interviews were conducted with six paediatric Otolaryngologist operating at a tertiary paediatric centre, with a minimum 1 year of experience using a 3D endoscopy system.
3. Thematic analysis of the surgeon's responses identified 3D endoscopy to provide improved surgical field visualisation which thus served as a valuable teaching tool.Two participants found impaired utility of 3D endoscopy compared to other surgical techniques in clinical scenarios when the width of the instrument did not allow for access to the surgical site.
In the smallest babies, the scope is likely too big…the scope was too large to adequately visualize the subglottis (Participant #3).

| DISCUSSION
Our qualitative investigation of paediatric Otolaryngologist experience in 3D endoscopic surgery found this innovative technology to improve visualisation thereby facilitating surgical and anatomical teaching.Moreover, 3D endoscopic technology was found to be particularly effective in laryngeal surgery, although the endoscope's width can limit its utility in certain clinical scenarios.

| Three-dimensional endoscopy as a teaching tool
All participants commented that 3D endoscopy could be effective to facilitate teaching.The 3D endoscopy system provides a more complete projection of complex anatomical structures including the vocal cords and surrounding topography of the larynx.Three-dimensional imaging of such structures allowed trainees to better understand anatomical relationships ultimately targeted to improve their surgical precision.Moreover, 3D endoscopy allowed supervising surgeons to more precisely follow surgical movements of trainees, thus improving the senior surgeons' confidence that manoeuvres were conducted in a safe manner.

| Implications for practice
Appreciable image enhancement using 3D endoscopy translated into the surgeons' ability to better delineate anatomical relationships.Notable paediatric clinical scenarios in which such delineation improved surgical experience was the larynx.In the instance of laryngeal papillomatosis, surgeons felt they could more safely perform an extensive resection of tissue and minimise airway traumatization due to improved confidence of the exact margin of disease.This thorough resection was found to double the interval between recurrent respiratory papillomatosis procedures.This finding builds upon previously defined benefits of 3D endoscopy for surgical treatment of laryngomalacia and subglottic cysts. 1,8Similarly, three surgeons noted they were better able to visualise the borders of vocal cords in medialization procedures.In contrast, the current 3D endoscope technology is limited to 4 mm in diameter, which restricted its use in narrow spaces including certain neonatal airways and paediatric middle ear spaces.
Anecdotally, two surgeons noted the stereoscopic vision was lost when the camera lens was frequently soiled during sinus surgery.This finding contrasts previous reports of a well-defined role for 3D endoscopy in endonasal surgery, albeit in adult patients. 9bjective surgeon experience of 3D endoscopy was improved with increased use.In particular, the initial technical challenges such as increased set-up time and equipment positioning optimization were overcome with experience.This is further evidenced by Moore and Bennett, 10 who found 90% of endoscopic surgical complications to occur in the first 30 patients on the learning curve.No adverse physical side effects were encountered by surgeons to limit their ability to perform the procedures in a safe and efficient manner.Altogether, the T A B L E 1 Themes identified from data analysis.

| Strengths and limitations
Our study is confined to a single institution due to the novel technol- [surgeons] have learned to simulate depth perception by moving the endoscope frequently to generate a 3D map in their mind.With the 3D endoscope, you have 3D perception immediately and you appreciate the relationship of different structures in different dimensions very quickly (Participant #1).… the 3D endoscopic view of the middle ear had greater depth perception [relative to 2D] of anatomical structures and their relationship to your instruments (Participant #2).This improved visualisation had clinical applicability to better discriminate laryngeal anatomy, thus facilitating laryngeal surgery.This was identified by four of the six participants.The main benefit [of 3D endoscopy] is ability for more precision due to the depth perception.This was particularly noticeable for laryngeal papillomatosis, where a fraction of a millimetre counts to get rid of disease and retain the normal structure" (Participant #5).

4 .
The surgeons interviewed found 3D endoscopy to improve surgical outcomes in paediatric airway surgery, particularly in surgeries involving the larynx.5. Further quantitative evaluation of patient outcomes could delineate the precise clinical role 3D endoscopy may hold in future paediatric Otolaryngology practice.F I G U R E 1 Three-dimensional endoscope operating room set up. "In surgical training, [3D endoscopy] gives you a better perspective to advise trainees on how to improve their technique, but also to recognize that techniques are being done safely and appropriately.I feel more confident that I can see exactly what they are doing" (Participant #1).This teaching benefit of 3D endoscopy was pervasive in all interviews.When there is an opportunity to teach, I would like to use [3D endoscopy] in almost every case (Participant #6) In contrast, all participants found 3D endoscopy to require additional set-up time and careful equipment positioning; however, the surgeons found that this resolved with increased device use and familiarity.The [support] staff must know what they are doing during set-up…there are no problems with the equipment itself (Participant #3).
ogy and related resource limitations; however, all paediatric Otolaryngologists interviewed in our study had substantial clinical experience with the 3D endoscopic technology.Our study offers new and diverse insight as the first to evaluate 3D endoscopy use in regular paediatric Otolaryngology practice.With increased 3D endoscopy resource access, quantitative evaluation of patient outcomes can serve to further clarify the precise role of 3D endoscopy in paediatric Otolaryngology surgery.Moreover, a subsequent cost analysis of 3D endoscopy use could better elucidate the innovative technology's role in publicly funded healthcare models.KEYWORDS laryngeal surgery, paediatric otolaryngology, qualitative research, surgical training, three-dimensional endoscopy