Reply to "Optimizing intraoral surgery video recording for residents' training during the COVID-19 pandemic: Comparison of 3 point of views using a GoPro".

Dear Sir,

We would like to acknowledge Navia et al. for their insightful viewpoint on device selection for intraoperative videography to improve residents’ education. Plastic and maxillofacial surgery operations are particularly difficult to record as the anatomy is often confined to a narrow surgical field with limited sightlines. While their description of the GoPro Hero 7 Black (GPH7B) provides a novel means of intraoperative video recording, Navia et al. provide relatively few information regarding the benefits of using a smartphone to produce high-quality surgical videos, which we argue may supersede alternative video recording systems.

First, the authors report GPH7B's increasing popularity in residents’ training, garnered by its ability to offer point-of-view (POV) high-quality video recording up to 4K with 60 frames per second (FPS). However, the GPH7B also has significant drawbacks, including its cost, fish lens distortion, and loss of detail in recording fine-scale anatomical structures. Newer smartphones offer similar video recording capabilities of up to 4K with 60 FPS, but generally perform better than the GPH7B in low-light conditions. The latest iPhone models (X, 11, 12 13) have lenses with a wider aperture compared to the GPH7B, allowing more light to hit the camera's sensor.

It has been reported that smartphones are incompatible with light-emitting diode operative room lights, resulting in a commonly reported flickering phenomenon as light pulses from overhead operating lights do not align with the smartphone camera's frame rate. However, slowing the smartphone camera's shutter speed using free smartphone applications is a simple means to completely remove this strobe effect. Alternatively, the exposure (brightness) may be manually adjusted using the native camera application on most recent smartphone models. Specifically, the latest iPhone models utilize an exposure compensation value control, which allows users to set and lock the focus and exposure of video recordings, thereby eliminating the risk of overexposure and evading the need of a filter or manual adjustment of shutter speed. These simple means of mitigating artifact in smartphone videography do not add to the already minimal cost and are not cumbersome to implement after a brief tutorial.

The smartphone is highly capable of providing point-of-view (POV) recording. We previously described two simple and low-cost means of achieving POV intraoperative video recording with a smartphone in facial plastic surgery operations. We demonstrated that POV smartphone recording using a head mount provided excellent image quality compared to other commercially available camera systems. Nevertheless, it is important to note that most head mounted video systems are subject to intense motion artifact due to the natural movements of the surgeon's head. The latest iPhone models have improved image stabilization technology, using both Optical Image Stabilization (OIS) and Electronic Stabilization, to stabilize shaky video recordings. Alternatively, we found that fastening the smartphone to a gooseneck clamp affixed to an intravenous pole provides more stable POV video recording, similar to the gimbal stabilization described by Navia et al.. Moreover, Navia et al. report that the head mounted smartphone assembly has a weight of 300 g, which could increase strain during long procedures. However, this is not of significant concern in shorter surgical procedures, and the video recording assembly itself may be best utilized to highlight specific surgical techniques as opposed to the entire procedure.

The wireless transmissibility, high-quality optical zoom, and ubiquity of smartphones, which are limitations of the GPH7B, cannot be understated. The ability to mirror the smartphone's screen onto operating room monitors or laptops is critical to ensure the camera is capturing an appropriate frame and may improve trainees’ ability to follow surgical steps in an otherwise crowded surgical field. The latest smartphones offer powerful improvements to optical zoom systems, like the iPhone 13, which has a 6x optical zoom range (3x optical zoom in, 2x optical zoom out) with minimal loss in video quality. Finally, the ubiquity of smartphones makes its use convenient and inexpensive relative to other video recording equipment.

The continued evolution of smartphone camera technology has made the smartphone an attractive tool for high-definition intraoperative videography. Therefore, while Navia et al. demonstrate an alternate means of intraoperative video recording, we hope the information provided in this letter will help readers better understand the advantages of smartphones in surgical recording.

Declaration of Competing Interest

None.