Rhinoplasty Using Three-Dimensional Analysis and Simulation

Artificial Intelligence for Rhinoplasty Design in Asian Patients

BACKGROUND

Rhinoplasty is one of the most challenging plastic surgeries because it lacks a uniform standard for preoperative design or implementation. For a long time, rhinoplasties were done without an accurate consensus of aesthetic design between surgeons and patients before surgery and consequently brought unsatisfactory appearance for patients. In recent years, three-dimensional (3D) simulation has been used to visualize the preoperative design of rhinoplasty, and good results have been achieved. However, it still relied on individual aesthetics and experience. The preoperative design remained a huge challenge for inexperienced surgeons and could be time-consuming to perform manually. Therefore, we adopted artificial intelligence (AI) in this work to provide a new idea for automated and efficient preoperative nasal contour design.

METHODS

We collected a dataset of 3D facial images from 209 patients. For each patient, both the original face and the manually designed face using 3D simulation software were included. The 3D images were transformed into point clouds, based on which we used the modified FoldingNet model for deep neural network training (by pytorch 1.12).

RESULTS

The trained AI model gained the ability to perform aesthetic design automatically and achieved similar results to manual design. We analysed the 1027 facial features captured by the AI model and concluded two of its possible cognitive modes. One is to resemble the human aesthetic considerations while the other is to fulfil the given task in a special way of the machine.

CONCLUSION

We presented the first AI model for automated preoperative 3D simulation of rhinoplasty in this study. It provided a new idea for the automated, individual and efficient preoperative design, which was expected to bring a new paradigm for rhinoplasty and even the whole field of plastic surgery.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Radix's Importance for Plastic Surgeons: A Descriptive Cross-Sectional Study

Background

Considering the importance of the nose in the beauty of the face, accurate and systematic three-dimensional nasal analysis of the nose before the procedure is essential. The radix, and so the nasofrontal and nasofacial angles, play an essential role in forming an aesthetically pleasing nose because they influence the length and projection of the nose. We aimed to measure information about the pre-operative radix position in our region.

Method

Pre-operative images were taken from our cases in the profile view. A checklist including radix location and projection, nasofrontal angle, and nasofacial angle were extracted from these images.

Results

Overall, 200 (100 males and 100 females) cases were enrolled. Thirty-two male cases and 48 females had abnormal radix position. Radix projection were normal in only 36 male cases and 18 females. The mean nasofrontal angle in the male and female groups was 119.2 and 128.2 respectively. The mean nasofacial angle was 29.8 in the female groups and 32.6 in the male group.

Conclusion

The reality of the current society of Iranian patients can be very different from the predictions of surgeons and can be far away from the statistics mentioned in western books. We tried to notify surgeons to thoroughly examine the patients prior to surgical operation by measuring parameters such as projection and position of the radix and nasofrontal and nasofacial angles.

Crushed Cartilage and Autologous Fat for Dorsal Nasal Refinement

BACKGROUND

Dorsal contour irregularities remain a potential undesirable sequela of rhinoplasty. Use of dorsal onlay grafts can camouflage such irregularities. In this article, a novel technique for dorsal onlay grafting utilizing crushed cartilage mixed with autologous fat is described. This study aims to assess long-term graft retention and aesthetic outcomes with this technique.

METHODS

Patients with >18-month follow-up who underwent primary open rhinoplasty with the described technique were reviewed. Three-dimensional photographs taken at multiple timepoints were overlaid with volumetric subtraction used to quantify graft retention. The Rhinoplasty module of the FACE-Q was completed by each patient, and the Rhinoplasty Assessment Scale Photographic (RASP) was completed by surgeon reviewers. Pre- and postoperative changes in dorsal height as well as RASP scores were compared with paired t-tests. Changes in BMI, dorsal volume, and dorsal height were compared with linear regression. P values <0.05 were considered significant.

RESULTS

Fourteen patients were included, mean age 32. Mean intermediate and final follow-up was 17.8 months and 28.9 months, respectively. There were no statistically significant dorsal height change (mean = 0.0 mm, p = 0.91) and minimal dorsal volume change (mean = 0.02 cm³, range:  0.08 to 0.13). Patients reported a high degree of satisfaction with facial/nasal appearance and psychological/social functioning. There was a statistically significant improvement in RASP scores (p < 0.001) postoperatively.

CONCLUSION

Crushed septal cartilage mixed with autologous fat is an effective option for dorsal nasal onlay in rhinoplasty and is associated with excellent graft retention, patient satisfaction, and nasal aesthetics.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Asymmetry of inferior turbinate in patients with nasal septum deviation and its significance for nasal ventilation surgery

PURPOSE

To investigate the asymmetry of the inferior turbinate (IT) in patients with nasal septum deviation (NSD).

METHODS

The paranasal sinus computed tomography (CT) of 100 patients with NSD were retrospectively investigated from February 2018 to December 2019. The thickness of IT, IT mucosa and IT bone, the distance between the IT and the midline were measured on both the concave and convex sides, and which correlation with NSD was analyzed.

RESULTS

The widths of the IT, IT bone and IT medial mucosa on the concave side were larger than those on the convex side (all P < 0.05). The distance from the IT and IT bone to the midline on the concave side was smaller than those on the convex side (P < 0.05, respectively). The degree of NSD had a negative correlation with the widths of the IT and IT bone on the convex side, and the distance between the IT and the midline on the concave side; and a positive correlation with the distance from IT and IT bone to the midline on the convex side, and IT mucosa thickness on the concave side (all P < 0.05).

CONCLUSION

The asymmetric IT width is mainly caused by both hypertrophies of the IT mucosa on the concave side and atrophy of the IT bone on the convex side. Therefore, during the surgery of nasal ventilation reconstruction, the IT on the convex side are suggested to be protected from intervention. In contrast, it is necessary to lateralize the IT bone and reduce the IT submucosal tissue on the concave side. However, routine excision of the IT bone is not recommended.

Aesthetic Rhinoplasty: Technique, 3-Dimensional Simulation, and Outcome Assessment

Communication of goals and realistic expectations between the surgeon and patient is a crucial step of aesthetic rhinoplasty. Three-dimensional (3D) imaging technology allows for sharing of simulated outcomes in the office setting, thereby facilitating this process. This article highlights the use of 3D rhinoplasty simulation in preoperative assessment and the senior author’s preferred surgical technique in open rhinoplasty.