Recapitulation of Unilateral Cleft Lip Nasal Deformity on Normal Nasal Structure: A Finite Element Model Analysis

Double Reinforcing Strategy with Perpendicular Plate of Ethmoid in Asian Secondary Unilateral Cleft Rhinoplasty: A Finite Element Analysis

BACKGROUND

Deviation and asymmetry relapse after secondary unilateral cleft rhinoplasty with septal extension graft is a common yet serious problem especially among Asian patients. Therefore, finding an effective approach to reduce deformity relapse remains a great challenge to plastic surgeons.

METHODS

In this study, authors established finite element models to simulate different nasal cartilage-corrected options and different reinforcing strategies in secondary unilateral cleft rhinoplasty. A load of 0.01N was given to the nasal tip to simulate the soft tissue pressure, while two loads of 0.5N were separately given to the anterior and posterior part of the septal extension graft to simulate the rhinoplasty condition. Maximum deformations were evaluated to make stability judgments.

RESULTS

The maximum deformation of different cartilage correction models in ascending order was: UCL deformity with septum correction, normal nasal cartilage, UCL nasal deformity, and UCL nasal deformity with lower lateral cartilage correction. When applied L-strut reinforcement graft was harvested from the perpendicular plate of the ethmoid bone, the maximum deformation of the models decreased significantly, and strong fixation of the septum could further enhance this decreasing effect.

CONCLUSIONS

Correcting the septum and lower lateral cartilage together could improve the structural stability and symmetry in secondary unilateral cleft rhinoplasty. To keep the corrected septum stable and thus reduce deformity relapse, reinforcing the L-strut with perpendicular plate of ethmoid graft while strongly anchoring the septal cartilage to the anterior nasal spine was proved to be effective in both finite element analysis and clinical observation.

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 .

Use of nasal retainers in the primary management of cleft lip: Current practices in France

BACKGROUND

The primary surgical management of cleft lip (CL) or cleft lip and palate (CLP) aims to achieve harmonious lip and nasal symmetry while ensuring satisfactory ventilation. Postoperative nasal retainers are commonly used, though both duration of use and conformer type used vary widely. This study aimed to establish an inventory of current practices for primary cheilorhinoplasty and nasal retainer use in France.

METHODS

A survey was sent to surgeons within and outside the French National Clefts and Facial Malformations (MAFACE) network. Questions focused on age when primary cleft closure is performed, retainer types used, conformation duration, and estimated patient compliance. Responses were collected March-July 2023.

RESULTS

Thirty-two surgeons responded with substantial variations in practices. For isolated CL, the age for primary cleft closure was 1-6 months, with 28 % performing surgery at 3 months, 12.5 % between 3 and 6 months, 44 % at 6 months. In cases with CLP, 63 % performed simultaneous surgery at 6 months. Two surgeons (6 %) reported preoperative nasoalveolar molding and 30 surgeons (94 %) reported postoperative nasal retainer use. Retainer type used immediately after surgery varied, with equal use of commercial retainers (31 %), silicone sheets (31 %), and in-house retainers (31 %). Duration of retainer prescription was in majority 3-4 months. Notably, 44 % of surgeons reported <70 % adherence rates for the recommended conformation duration, while 25 % reported very good compliance.

CONCLUSION

Primary cheilorhinoplasty and nasal conformation practices are highly diverse in France. Suboptimal patient compliance demonstrates the need for improved retainer design and strategies to enhance compliance.

M-Shaped Auricular Cartilage Grafts for Correcting Short Nose Deformity in Asians: A Retrospective Study

BACKGROUND

The demand for rhinoplasty in Asia is growing annually, and short nose deformity has been one of the main reasons for the surgery due to its high incidence. There is an urgent need for rhinoplasty suitable for Asians because of their different facial features from Westerners. The M-shaped auricular cartilage rhinoplasty has been developed as a new method for correcting short nose deformity for Asians. This study aimed to evaluate the aesthetic and functional results of M-shaped auricular cartilage rhinoplasty compared to clinically commonly used rhinoplasty methods.

METHODS

A total of 45 patients were enrolled and divided into three groups of 15 patients: The first group underwent M-shaped auricular cartilage rhinoplasty, the second group underwent auricular-septal cartilage rhinoplasty, and the third group underwent overlapped auricular cartilage rhinoplasty. All of these patients underwent comprehensive rhinoplasty and had silicone or expanded polytetrafluoroethylene implants in the dorsum of their noses.

RESULTS

The patient score improvements on the three patient-reported outcome measures were higher in the M-shaped auricular cartilage rhinoplasty group (1.65/1.79/0.11) compared with the overlapped auricular cartilage rhinoplasty group (1.40/1.51/0.05), and the score improvements in the auricular-septal cartilage rhinoplasty group (2.04/1.98/0.28) were the highest.

CONCLUSIONS

This is a retrospective clinical study demonstrating the clinical efficacy of M-shaped auricular cartilage rhinoplasty. Compared with the overlapped auricular cartilage rhinoplasty, the effect of this novel M-shaped method is better. However, when compared to the auricular-septal cartilage rhinoplasty with septal extension and reinforcement using nasal septal cartilage, its effect is slightly worse.

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 .

Correction of Short Nose Using M-shaped Cartilage in Asian Patients: Finite Element Analysis and Recommendations for Surgery

BACKGROUND

Using M-shaped cartilage grafts is a new method for the correction of short nose deformity with good effect for Asians. Although the basic approach to M-shaped cartilage surgery is well understood, there is a great deal of uncertainty when plastic surgeons perform the procedure, and still a lack of standard guidance on the specific details.

METHODS

In this study, the authors used finite element analysis to explore and compare postoperative cartilage stability of different fixing methods, different suturing positions, and different sizes of M-shaped cartilage. The authors applied a 0.01 N load to a 1 cm2 area of the nasal tip to simulate nasal tip palpation and compared the maximum deformations of different groups, which were used to make stability judgments.

RESULTS

The maximum deformation of the model was the least when the M-shaped cartilage was fixed medially to the septal cartilage and laterally to the outer crura of the lower lateral cartilage. At the same time, the maximum deformation was the least when the M-shaped cartilage was sutured to the middle of the nasal septal cartilage. Besides, the length of M-shaped cartilage was preferably around 30 mm, while its width was not worthy of being overly concerned.

CONCLUSIONS

For optimal postoperative stability of Asian short nose correction, the M-shaped cartilage should be sutured and fixed medially to the middle of the septal cartilage and laterally to the lateral crura of the lower lateral cartilage, and the length of the M-shaped cartilage should be controlled at around 30 mm.

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 .

ChatGPT for shaping the future of dentistry: the potential of multi-modal large language model

The ChatGPT, a lite and conversational variant of Generative Pretrained Transformer 4 (GPT-4) developed by OpenAI, is one of the milestone Large Language Models (LLMs) with billions of parameters. LLMs have stirred up much interest among researchers and practitioners in their impressive skills in natural language processing tasks, which profoundly impact various fields. This paper mainly discusses the future applications of LLMs in dentistry. We introduce two primary LLM deployment methods in dentistry, including automated dental diagnosis and cross-modal dental diagnosis, and examine their potential applications. Especially, equipped with a cross-modal encoder, a single LLM can manage multi-source data and conduct advanced natural language reasoning to perform complex clinical operations. We also present cases to demonstrate the potential of a fully automatic Multi-Modal LLM AI system for dentistry clinical application. While LLMs offer significant potential benefits, the challenges, such as data privacy, data quality, and model bias, need further study. Overall, LLMs have the potential to revolutionize dental diagnosis and treatment, which indicates a promising avenue for clinical application and research in dentistry.

Application of a Novel Nasal Clip for Nostril Retention After Primary Unilateral Cleft Rhinoplasty

OBJECTIVE

This study aimed to investigate the outcomes of using a novel nasal clip designed for nostril retention after primary unilateral cleft rhinoplasty.

DESIGN

This is a retrospective study.

SETTING

Department of Cleft Lip and Palate in a stomatological hospital.

PATIENTS

A retrospective study was conducted on 57 patients who had a unilateral complete cleft lip without cleft palate and underwent primary surgical repair.

INTERVENTIONS

The patients were categorized into 3 groups: the group in which the conventional nasal retainer was used, that in which the nasal clip was used, and the control group in which no postoperative nasal retainer was used. The nasal retainer or our nasal clip was applied 7 days after primary surgical repair and kept in the nostrils of children from 6 to 12 months.

MAIN OUTCOME MEASURES

Noses underwent photogrammetry preoperatively, postoperatively, and at follow-up. The nose was also subjectively scored at the follow-up.

RESULTS

The nasal retainer and the nasal clip significantly minimized relapse as determined by nasal tip deviation. The nasal clip sustained nasal symmetry, as determined by the postoperative nostril width ratio, better than did the conventional retainer. After 6 to 12 months, the nasal clip achieved better columellar morphology and a more symmetric nasal base than did the conventional nasal retainer. Statistical differences in subjective scores between the control and nostril retention groups were noted.

CONCLUSION

The application of the novel nasal clip after primary unilateral cleft rhinoplasty preserves nasal morphology and reduces postoperative relapse without the need for adhesive tape.

Airflow of the Two-Port Velopharyngeal Closure: Study Using Computational Fluid Dynamics

Posterior pharyngeal flap palatoplasty is used to restore the function of velopharyngeal (VP) closure, after which 2 ports remain between the nasal and oral cavity. The authors hypothesized that the airflow dynamics of the upper airway is different in PPF patients compared to health subjects, who only has 1 movable port. Twenty adults who have multislice spiral computed tomography scan were included in this study. Two cylinders (radius, 2.00 mm; height, 4.5 mm) were used to recapitulate the 2-port VP structure after PPF palatoplasty. The areas of ports were modified by changing the radius of 2 cylinders. Real-time computational fluid dynamics simulation was used to capture the airflow velocity and pressures through the 2 ports. The airflow velocity and pressure of upper airway were recorded as the total areas of 2 VP ports increased. The total orifice areas of the 2-port VP closure for 4 VP conditions, including adequate closure, adequate/borderline closure, borderline/inadequate closure, and inadequate closure, were demonstrated. Significant differences between the 2-port VP function for demonstrating PPF reconstruction and the 1-port VP function were found. Airflow dynamics is dependent on the VP structure. The 2-port airflow model for mimicking VP closure after PPF palatoplasty demonstrated airflow characteristics that were significantly different from the 1-port model in normal VP closure.

Computational technology for nasal cartilage-related clinical research and application

Surgeons need to understand the effects of the nasal cartilage on facial morphology, the function of both soft tissues and hard tissues and nasal function when performing nasal surgery. In nasal cartilage-related surgery, the main goals for clinical research should include clarification of surgical goals, rationalization of surgical methods, precision and personalization of surgical design and preparation and improved convenience of doctor-patient communication. Computational technology has become an effective way to achieve these goals. Advances in three-dimensional (3D) imaging technology will promote nasal cartilage-related applications, including research on computational modelling technology, computational simulation technology, virtual surgery planning and 3D printing technology. These technologies are destined to revolutionize nasal surgery further. In this review, we summarize the advantages, latest findings and application progress of various computational technologies used in clinical nasal cartilage-related work and research. The application prospects of each technique are also discussed.

Force balance reconstruction of the orbicularis oris in unilateral incomplete cleft lip

PURPOSE

To demonstrate a maneuver for achieving optimal force balance of reconstructed orbicularis oris during primary unilateral incomplete cleft lip reconstruction.

METHODS

The surgical maneuver was performed as follows: the length of the orbicularis oris on the noncleft side is first isolated and adjusted to be equal to the length of the muscle on the cleft side. The remaining muscle from the noncleft side near the midline is used to fill in the vermilion tubercle, and finally, the two orbicularis oris muscles are sutured at the midline. Finite element analysis was utilized to model the biomechanics of our novel surgical method.

RESULTS

Finite element analysis showed that when the lengths of two orbicularis oris muscles were the same after primary cleft lip repair, the stress on this muscle system was minimized under different lip conformations. Seventeen cleft lip patients were enrolled to receive reconstruction with this new maneuver. Significant differences were found in (1) noncleft/cleft alar base width, nasal dorsum angle, columella length relationship between two sides, and columella angle under the comparison between preoperative and postoperative; (2) noncleft/cleft alar base width, nasal dorsum angle, and columella angle under the comparison between preoperative and follow-up; and (3) columella length relationship between two sides under the comparison between postoperative and follow-up.

CONCLUSION

Force balance of the orbicularis oris muscles is important during unilateral incomplete cleft lip repair. This surgical maneuver for achieving force balance of the orbicularis oris and the muscle system of the lips is easy to perform and can help avoid relapses.

Computational Fluid Dynamic Analysis of Different Velopharyngeal Closure Patterns

Objective:

Velopharyngeal (VP) closure has high impact on the quality of life, especially in patients with cleft palate. For better understanding the VP closure, it is important to understand the airflow dynamics of different closure patterns, including circular, coronal, sagittal, and circular with a Passavant’s ridge. The purpose of this study was to demonstrate the airflow characteristics of different velopharyngeal closure patterns.

Methods:

Sixteen adults with no notable upper airway abnormality who needed multislice spiral computed tomography scans as part of their clinical care. Airways were reconstructed. A cylinder and a cuboid were used to replace the VP port in three models of VP port patterns. Flow simulations were carried using computational fluid dynamics. Airflow pressures in the VP orifice, oral cavity and nasal cavity, as well as airflow velocity through the velopharyngeal orifice, were calculated.

Results:

The airflow dynamics at the velopharynx were different among different velopharyngeal patterns as the area of the velopharyngeal port increased from 0 to 25 mm2. The orifice areas of different closure conditions in four velopharyngeal closure patterns were significantly different. The maximal orifice area for adequate velopharyngeal closure was 7.57 mm2 in the coronal pattern and 6.21 mm2 in the sagittal pattern.

Conclusions:

Airflow dynamics of the velopharynx were correlated to the velopharyngeal closure patterns. Different closure patterns had different largest permitted orifice areas for getting the appropriate oral pressures for normal speech.

Biomechanical analyses of common suspension sutures in primary cleft lip rhinoplasty

Background

For a better understanding of common suspension sutures during primary cleft lip nasal rhinoplasty, the biomechanical consequences of those sutures need to be demonstrated.

Methods

A finite element model of the infant specimen was established. The closure of cleft lip and four different specific suspension sutures were simulated by loading different forces on the model: 1. F1 to simulate the suture fastening both medial crura together; 2. F2 to simulate the suture which sewed both medial crura and the non-cleft-side upper lateral cartilage together; 3. F3 to simulate the suture elevating the alar cartilage cranially; 4. F4 to simulate the suture elevating the alar cartilage superiorly. The deformation and stress distribution consequent to each maneuver were analyzed in details.

Results

The deviation of columella was restored through the closure of cleft lip. Different suspension sutures had different biomechanical effects on the nasal structure. All suspension sutures had the function on elevating the alar cartilage. F2 had no function on restoring the collapse of the nasal tip. The suture which fastened both medial crura together leaded to the lowest stress on the skin envelope.

Conclusions

Each suspension suture had its characteristics respectively. The simulation suggested that F1, the suture which fastened both medial crura, could be the most potential maneuver for cleft lip rhinoplasty because it can symmetrically restore the shape of the nose without incurring a significant increase in stress.

Analysis of Velopharyngeal Functions Using Computational Fluid Dynamics Simulations

Objectives:

Competent velopharyngeal (VP) function is the basis for normal speech. Understanding how VP structure influences the airflow during speech details is essential to the surgical improvement of pharyngoplasty. In this study, we aimed to illuminate the airflow features corresponding to various VP closure states using computed dynamic simulations.

Methods:

Three-dimensional models of the upper airways were established based on computed tomography of 8 volunteers. The velopharyngeal port was simulated by a cylinder. Computational fluid dynamics simulations were applied to illustrate the correlation between the VP port size and the airflow parameters, including the flow velocity, pressure in the velopharyngeal port, as well as the pressure in oral and nasal cavity.

Results:

The airflow dynamics at the velopharynx were maintained in the same velopharyngeal pattern as the area of the velopharyngeal port increased from 0 to 25 mm2. A total of 5 airflow patterns with distinct features were captured, corresponding to adequate closure, adequate/borderline closure (Class I and II), borderline/inadequate closure, and inadequate closure. The maximal orifice area that could be tolerated for adequate VP closure was determined to be 2.01 mm2.

Conclusion:

Different VP functions are of characteristic airflow dynamic features. Computational fluid dynamic simulation is of application potential in individualized VP surgery planning.