Midfacial soft-tissue changes after mandibular setback surgery with or without paranasal augmentation: cone-beam computed tomography (CBCT) volume superimposition

Morphological Measurement of Asian Osteal Nasal Base for Paranasal Augmentation

BACKGROUND

Paranasal augmentation has been a popular approach in restoring Asian patients' lateral profile. Irregular surface in the surgical area emphasizes the importance of morphological evidence for the preoperative evaluation and the design of paranasal implants.

METHODS

We retrospectively collected craniofacial computer tomography scans of patients in the department of plastic surgery from 2020 to 2022. The imaging data were imported to Mimics (version 20.0; Materialize, Leuven, Belgium) for three-dimensional reconstruction. Measurements of osteal nasal base were performed in 3-matics (version 12.0; Materialize). The severity of paranasal concavity was graded by a senior doctor to study the correlation with measured variables.

RESULTS

Fifty-seven patients with a median age of 27 years (IQR: 22-33) were included in the study. For design of paranasal implants, the lengths of both lower and lateral edge were measured for reference. In the regression analysis, the alar base-alveolar process angle was significantly associated with the degrees of paranasal concavity (OR = 1.222, p = 0.00001).

CONCLUSIONS

Morphological data of osteal nasal base were measured and presented in the current study. The analysis supported that alar base-alveolar process angle be used for preoperative grading and evaluation to help guiding treatment decisions.

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 .

Three-dimensional soft tissue landmark detection with marching cube algorithm

Current method of analyzing three-dimensional soft tissue data, especially in the frontal view, is subjective and has poor reliability. To overcome this limitation, the present study aimed to introduce a new method of analyzing soft tissue data reconstructed by marching cube algorithm (Program S) and compare it with a commercially available program (Program A). Cone-beam computed tomography images of 42 patients were included. Two orthodontists digitized six landmarks (pronasale, columella, upper and lower lip, right and left cheek) twice using both programs in two-week intervals, and the reliability was compared. Furthermore, computer-calculated point (CC point) was developed to evaluate whether human error could be reduced. The results showed that the intra- and inter-examiner reliability of Program S (99.7-100% and 99.9-100%, respectively) were higher than that of Program A (64.0-99.9% and 76.1-99.9%, respectively). Moreover, the inter-examiner difference of coordinate values and distances for all six landmarks in Program S was lower than Program A. Lastly, CC point was provided as a consistent single point. Therefore, it was validated that this new methodology can increase the intra- and inter-examiner reliability of soft tissue landmark digitation and CC point can be used as a landmark to reduce human error.

Paranasal Augmentation: A Viable and Simplified Modality With Diced Expanded Polytetrafluoroethylene

A flat or concave lower midface profile is generally considered less attractive. Paranasal augmentation is usually performed to move paranasal deficiency to relative convexity. Herein, we present a viable and simplified modality with diced expanded polytetrafluoroethylene to correct paranasal deficiency. Between February of 2020 and April of 2021, 19 patients underwent procedures to correct paranasal deficiency. Paranasal augmentation was performed with diced expanded polytetrafluoroethylene. All procedures were performed via intranasal approach. Preoperative and postoperative photographs were taken. Of these 19 patients (18 women and 1 man), deficiency of 18 patients were caused by congenital factors and 1 by cleft deformities. All but 1 procedures were carried out bilaterally. Procedures were performed in conjunction with additional operations mainly including rhinoplasty and minimally invasive midface lift. Age of patients ranged from 19 to 57 years, with a mean of 37 years. Follow-up time ranged from 8 to 22 months, with a mean of 12.6 months. All patients were satisfied with esthetic improvement and facial holistic profile. No severe complications and reoperation arisen in any of the patients. Temporary discomfort involved foreign body sensation in 1 case and numbness in 2 cases. The present technique provides a viable and simplified method to give the face a more balanced appearance and achieves esthetically superior results.

Paranasal Augmentation Using Diced Costal Cartilage for Midface Concavity: A Retrospective Study of 68 Patients

BACKGROUND

Paranasal augmentation was effective management for midface concavity. Both alloplastic graft (e.g. silicone, porous polyethylene, or expanded polytetrafluorethylene) and autologous tissue (e.g. costal cartilage) were used for paranasal augmentation. The study aims to evaluate the safety and efficacy of paranasal augmentation using diced costal cartilage for midface concavity.

METHODS

A retrospective review of demographic data and complications was conducted for consecutive patients who underwent paranasal augmentation using diced costal cartilage. A questionnaire was used for investigating the patient's satisfaction (i.e. overall satisfaction, bilateral alar bases symmetry, improvement of concavity, and foreign body sensation). Patients' photographs were used to evaluate aesthetic outcomes (i.e. overall satisfaction, bilateral alar bases symmetry, and improvement of concavity) by third-party doctors.

RESULTS

Sixty-eight patients (60 females; mean age, 27.1 ± 8.2 years) were included. During a median follow-up of 6.5 months, costal cartilage migration occurred in 13 (19.1%) patients and partial resorption occurred in 2 (2.9%) patients. Seventy-five per cent of the patients and 98.5% of the doctors reported overall satisfaction. Bilateral alar bases asymmetry by 20 (29.4%) patients, no improvement of concavity by 13 (19.1%) patients, and foreign body sensation by 13 (19.1%) patients were reported. While bilateral alar bases asymmetry was not reported, improvement of concavity was reported in 67 (98.5%) patients by third-party doctors. On both univariate and multivariate analyses, improvement of concavity was significantly associated with patients' overall satisfaction (p = 0.008 and 0.045, respectively), while bilateral alar bases symmetry and foreign body sensation were not (all p > 0.05).

CONCLUSIONS

Paranasal augmentation using diced costal cartilage seems a safe and effective method for midface concavity. Improvement of concavity may be significantly associated with patients' overall satisfaction.

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 .

Three-Dimensional Digital Image Analysis of Skeletal and Soft Tissue Points A and B after Orthodontic Treatment with Premolar Extraction in Bimaxillary Protrusive Patients

Aim. To investigate the effect of changes in incisor tip, apex movement, and inclination on skeletal points A and B and characterize changes in skeletal points A and B to the soft tissue points A and B after incisor retraction in Angle Class I bimaxillary dentoalveolar protrusion. Methods. Twenty-two patients with Angle Class I bimaxillary dentoalveolar protrusion treated with four first premolar extractions were included in this study. The displacement of skeletal and soft tissue points A and B was measured using cone-beam computed tomography (CBCT) using a three-dimensional coordinate system. The movement of the upper and lower incisors was also measured using CBCT-synthesized lateral cephalograms. Results. Changes in the incisal tip, apex, and inclination after retraction did not significantly affect the position of points A and B in any direction (x, y, z). Linear regression analysis showed a statistically significant relationship between skeletal point A and soft tissue point A on the anteroposterior axis (z). Skeletal point A moved forward by 0.07 mm, and soft tissue point A moved forward by 0.38 mm, establishing a ratio of 0.18: 1 (r = 0.554, p < 0.01). Conclusion. The positional complexion of the skeletal points A and B was not directly influenced by changes in the incisor tip, apex, and inclination. Although the results suggest that soft tissue point A follows the anteroposterior position of skeletal point A, its clinical significance is suspected. Thus, hard and soft tissue analysis should be considered in treatment planning.

The effect of subspinal Le Fort I osteotomy and alar cinch suture on nasal widening

The aim of this retrospective study was to evaluate the relationships between upper jaw movements and nasal soft-tissue changes in patients who have undergone subspinal Le Fort I osteotomy combined with alar cinch suture. Single and multivariate linear regression analyses were used to examine the relationships between greatest inter-alar width (GAW) and maxillary advancement, maxillary impaction, and rotational movements. The database of our referral hospital was searched for patients who had undergone upper jaw surgery with a subspinal LFI osteotomy to correct dentoskeletal deformities between April 2012 and June 2016. Thirty-eight of the patients (15 men and 23 women) who were identified were eligible for inclusion. The average change in inter-alar width (ΔGAW) was +1.7 ± 1.2 mm. GAW increased by 0.3 mm (p < 0.0001) for each millimetre of maxillary advancement, and increased by 0.5 mm (p < 0.0001) for each millimetre of maxillary impaction. GAW increased by 0.2 mm for each degree of counterclockwise rotation of the occlusal plane (p < 0.0001). An analysis of our data compared with the current literature confirmed that subspinal Le Fort I combined with alar cinch suture reduced alar base widening.

Standard and Customized Alloplastic Facial Implants Refining Orthognathic Surgery: Outcome Evaluation

PURPOSE

Conventional orthognathic osteotomies provide appropriate functional outcomes but might be unable to correct midface deficiency, achieve a satisfactory outcome in asymmetrical cases, or allow sufficient chin advancement. We evaluated the outcome of both standard and customized facial high-density porous polyethylene implants used to refine the cosmetic outcome of orthognathic surgery.

PATIENTS AND METHODS

We implemented a retrospective study. The sample was composed of all patients who underwent facial alloplastic augmentation between June 2011 and October 2018 in our department. The complication rate was recorded after a mean follow-up period of 41 months postoperatively, and patient satisfaction was assessed through a qualitative evaluation based on an 11-item questionnaire.

RESULTS

The sample was composed of 24 implants placed in 14 patients: 13 mandibular angle implants, among which 4 were customized; 8 malar implants; and 3 chin implants. No physical complications such as hematoma, infection, migration, or hypoesthesia were observed. Two implants had to be removed because of early unsatisfactory esthetic outcomes. Of 14 patients, 11 answered our questionnaire. Eighty-two percent strongly agreed that the overall outcome was satisfactory.

CONCLUSIONS

The results of this study confirm the low physical complication rate described in the literature, and the esthetic complication rate remains lower than the rates observed in previous reports. A high satisfaction rate was found among patients. The lowest mean satisfaction score was noted for appropriate implant symmetry (3.5), whereas the highest mean satisfaction score (3.8) was achieved when using customized implants. If standard high-density porous polyethylene implants appear to be relevant adjuncts to orthognathic surgery, customized implants seem to achieve higher satisfaction, although their prohibitive cost should be considered.

Effect of Le Fort I Maxillary Advancement and Clockwise Rotation on the Anteromedial Cheek Soft Tissue Change in Patients with Skeletal Class III Pattern and Midface Deficiency: A 3D Imaging-Based Prediction Study

Patients with a skeletal Class III deformity may present with a concave contour of the anteromedial cheek region. Le Fort I maxillary advancement and rotational movements correct the problem but information on the impact on the anteromedial cheek soft tissue change has been insufficient to date. This three-dimensional (3D) imaging-assisted study assessed the effect of surgical maxillary advancement and clockwise rotational movements on the anteromedial cheek soft tissue change. Two-week preoperative and 6-month postoperative cone-beam computed tomography scans were obtained from 48 consecutive patients who received 3D-guided two-jaw orthognathic surgery for the correction of Class III malocclusion associated with a midface deficiency and concave facial profile. Postoperative 3D facial bone and soft tissue models were superimposed on the corresponding preoperative models. The region of interest at the anteromedial cheek area was defined. The 3D cheek volumetric change (mm3; postoperative minus preoperative models) and the preoperative surface area (mm2) were computed to estimate the average sagittal movement (mm). The 3D cheek mass position from orthognathic surgery-treated patients was compared with published 3D normative data. Surgical maxillary advancement (all p < 0.001) and maxillary rotation (all p < 0.006) had a significant effect on the 3D anteromedial cheek soft tissue change. In total, 78.9%, 78.8%, and 78.8% of the variation in the cheek soft tissue sagittal movement was explained by the variation in the maxillary advancement and rotation movements for the right, left, and total cheek regions, respectively. The multiple linear regression models defined ratio values (relationship) between the 3D cheek soft tissue sagittal movement and maxillary bone advancement and rotational movements of 0.627 and 0.070, respectively. Maxillary advancements of 3-4 mm and >4 mm resulted in a 3D cheek mass position (1.91 ± 0.53 mm and 2.36 ± 0.72 mm, respectively) similar (all p > 0.05) to the 3D norm value (2.15 ± 1.2 mm). This study showed that both Le Fort I maxillary advancement and rotational movements affect the anteromedial cheek soft tissue change, with the maxillary advancement movement presenting a larger effect on the cheek soft tissue movement than the maxillary rotational movement. These findings can be applied in future multidisciplinary-based decision-making processes for planning and executing orthognathic surgery.

Paranasal Augmentation Using Multi-Folded Expanded Polytetrafluorethylene (ePTFE) in the East Asian Nose

BACKGROUND

Paranasal augmentation has commonly been performed utilizing alloplastic materials such as silicone or porous polyethylene. However, there are problems such as bone absorption, implant migration, and infection risk attributable to intraoral approaches.

OBJECTIVES

The authors attempted anterior positioning of the alar crease junction as an adjunct method of rhinoplasty. The authors aimed to determine the long-term results of the intranasal approach for placement of multi-folded expanded polytetrafluorethylene (ePTFE).

METHODS

A retrospective review was conducted of patients who underwent intranasal surgical approach for paranasal augmentation employing multi-folded ePTFE implants in 19 septorhinoplasties who were followed-up for 3 to 10 years. Patient charts were reviewed for demographic information, concomitant operations, and complications. Preoperative and postoperative photographs were utilized to evaluate operative outcomes. The photographs were reformatted to 2-dimensional images employing standard photographic methods.

RESULTS

Of the 19 patients treated, 17 were female and 2 were male; ages ranged from 18 to 58 years. All patients reported improvement in their lateral profiles and were pleased at follow-up. There were no major complications, no nerve or vascular supply compromise, and no cases of implant malposition. The average increase in soft tissue outline near the alar crease junction was more than 3.2 mm (P < 0.001), but the alar base did not became wider.

CONCLUSIONS

Paranasal augmentation with multi-folded ePTFE is a simple, safe, and effective method that can readily improve the lateral profile. In particular, the intranasal approach combined with rhinoplasty can synergistically improve outcomes and lead to greater patient satisfaction.

LEVEL OF EVIDENCE: 4

Comparative Study of the Effect of Paranasal Augmentation With Autologous Bone in Orthognathic Surgery

PURPOSE

The purpose of the present study was to compare the effectiveness of the 3 orthognathic surgical options among the patients who had had mandibular prognathism with a concave midfacial profile.

PATIENTS AND METHODS

A total of 72 patients with mandibular prognathism with a concave midfacial profile were divided into 3 groups. We compared the lateral profile changes using lateral cephalograms. The images were taken before surgery (T0) and at least 6 months to 1 year after surgery (T1). After computerization of the preoperative cephalograms (T0), the surgical changes (T1 minus T0) were measured by computerizing the postoperative cephalograms. Group 1 (n = 21) had undergone bilateral sagittal split osteotomies, group 2 (n = 36) had undergone bilateral sagittal split osteotomy with autologous bone paranasal augmentation, and group 3 (n = 15) had undergone bilateral sagittal split osteotomies and Le Fort I osteotomy.

RESULTS

After surgery, all the landmarks and values showed changes. Among them, quantitative changes could be observed in all the cheek points and cheek lines. The average of the overall cheek points had increased by ∼0.56 mm in group 1, ∼1.85 mm in group 2, and ∼2.39 mm in group 3, horizontally.

CONCLUSIONS

The results of the present study suggest approximately comparative values among the 3 surgical options for patients and surgeons considering orthognathic surgery. In addition, autologous bone paranasal augmentation can be considered as an alternative for Le Fort I osteotomy in specific conditions.

The Influence of Paranasal Augmentation on the Measurement of the Nose for the Treatment of Midfacial Concavity

BACKGROUND

A concave midface with its associated deep nasolabial folds is more aesthetically displeasing than a convex midface. Midfacial concavity may be addressed with autologous tissue and implants.

OBJECTIVES

The aim of this study was to determine the effect of paranasal augmentation on photogrammetric parameters.

METHODS

Between July 2013 and August 2016, 12 patients underwent paranasal augmentation to address midface concavity. Augmentation was performed with autologous rib cartilage, autologous mandibular bone, or preshaped porous polyethylene (PPE). All operations were performed through the upper gingivobuccal approach. Twelve patients who underwent malar reduction using the same approach acted as a control group to account for the influence of the approach on soft tissue change. Preoperative and postoperative measurements were made photogrammetrically.

RESULTS

The average follow-up period was 12.8 months (range, 5-30 months) for both groups. The mean thickness of augmentation grafts was 5.18 mm (range, 3-7 mm). Alar width and alar base width increased 4.84% (P = 0.01) and 7.66% (P = 0.01), respectively. The nasolabial angle increased from 97.2°to 103.6° and the columellar inclination increased from 116.0° to 119.1° but neither were statistically significant. Photogrammetric parameters did not change significantly in the control group. Partial wound dehiscence occurred in one case. There was greater postoperative increase in alar width (P = 0.020), alar base width (P = 0.024), and nasolabial angle (P = 0.033) in the experimental group compared to the control group.

CONCLUSIONS

Paranasal augmentation using PPE or autologous material generates measurable soft tissue changes designed to enhance paranasal aesthetics.

LEVEL OF EVIDENCE 3

State-of-the-art three-dimensional analysis of soft tissue changes following Le Fort I maxillary advancement

We describe the comprehensive 3-dimensional analysis of facial changes after Le Fort I osteotomy and introduce a new tool for anthropometric analysis of the face. We studied the cone-beam computed tomograms of 33 patients taken one month before and 6-12 months after Le Fort I maxillary advancement with or without posterior vertical impaction. Use of a generic facial mesh for dense correspondence analysis of changes in the soft tissue showed a mean (SD) anteroposterior advancement of the maxilla of 5.9 (1.7) mm, and mean (SD) minimal anterior and posterior vertical maxillary impaction of 0.1 (1.7) mm and 0.6 (1.45) mm, respectively. It also showed distinctive forward and marked lateral expansion around the upper lip and nose, and pronounced upward movement of the alar curvature and columella. The nose was widened and the nostrils advanced. There was minimal forward change at the base of the nose (subnasale and alar base) but a noticeable upward movement at the nasal tip. Changes at the cheeks were minimal. Analysis showed widening of the midface and upper lip which, to our knowledge, has not been reported before. The nostrils were compressed and widened, and the lower lip shortened. Changes at the chin and lower lip were secondary to the limited maxillary impaction.

Comparative validity and reproducibility study of various landmark-oriented reference planes in 3-dimensional computed tomographic analysis for patients receiving orthognathic surgery

Background

Three-dimensional computed tomographic imaging has become popular in clinical evaluation, treatment planning, surgical simulation, and outcome assessment for maxillofacial intervention. The purposes of this study were to investigate whether there is any correlation among landmark-based horizontal reference planes and to validate the reproducibility and reliability of landmark identification.

Materials and Methods

Preoperative and postoperative cone-beam computed tomographic images of patients who had undergone orthognathic surgery were collected. Landmark-oriented reference planes including the Frankfort horizontal plane (FHP) and the lateral semicircular canal plane (LSP) were established. Four FHPs were defined by selecting 3 points from the orbitale, porion, or midpoint of paired points. The LSP passed through both the lateral semicircular canal points and nasion. The distances between the maxillary or mandibular teeth and the reference planes were measured, and the differences between the 2 sides were calculated and compared. The precision in locating the landmarks was evaluated by performing repeated tests, and the intraobserver reproducibility and interobserver reliability were assessed.

Results

A total of 30 patients with facial deformity and malocclusion—10 patients with facial symmetry, 10 patients with facial asymmetry, and 10 patients with cleft lip and palate—were recruited. Comparing the differences among the 5 reference planes showed no statistically significant difference among all patient groups. Regarding intraobserver reproducibility, the mean differences in the 3 coordinates varied from 0 to 0.35 mm, with correlation coefficients between 0.96 and 1.0, showing high correlation between repeated tests. Regarding interobserver reliability, the mean differences among the 3 coordinates varied from 0 to 0.47 mm, with correlation coefficients between 0.88 and 1.0, exhibiting high correlation between the different examiners.

Conclusions

The 5 horizontal reference planes were reliable and comparable for 3D craniomaxillofacial analysis. These reference planes were useful in standardizing the orientation of 3D skull models.

Cone beam computed tomographic analyses of the position and course of the mandibular canal: relevance to the sagittal split ramus osteotomy

Purpose. The aim of this study was to document the position and course of the mandibular canal through the region of the mandibular angle and body in dental patients, using cone beam computed tomographic imaging. Methods. The position and course of the mandibular canal from the region of the third molar to the first molar were measured at five specific locations in the same plane: at three different positions just between the first and second molars; between the second and third molars; and just distal to the third molar. Results. The study sample was composed of 500 hemimandibles from 250 dental patients with a mean age of 26.32. Significant differences were found between genders, distances, and positions. B decreased significantly from the anterior positions to the posterior positions in both females and males. The mean values of S and CB increased significantly from the posterior positions to the anterior positions in both females and males. Conclusion. Because the sagittal split ramus osteotomy is a technically difficult procedure, we hope that the findings of the present study will help the surgeon in choosing the safest surgical technique for the treatment of mandibular deformities.

Subnasal modified Le Fort I osteotomy: indications and results

PURPOSE

To study the possible morphologic changes in the nose after subnasal modified Le Fort I maxillary osteotomy to correct class III dentofacial deformities in patients with considered normal nasal morphology.

MATERIAL AND METHODS

Fifteen patients (7 males, 8 females) requiring maxillary advancement to treat class III dentofacial deformities were studied prospectively between January 2004 and January 2011. All the patients had an adequate projection of the nasal tip preoperatively preventing a conventional Le Fort I osteotomy. Patients received preoperatively (T1), 6 months after surgery (T2), and 12 months after the initial surgical procedure (T3) lateral cephalograms, CT-3D studies and clinical nose analysis to measure different morphologic variables including: the alar/nose base width, nasal tip protrusion and nasal bridge length using a digital sliding caliper directly on the soft-tissue surface of the face.

RESULTS

Mean age was 26.2 years, range 20-36 years. A significant advancement of the maxilla was noted postoperatively (mean 7.5 mm). After surgery the different anthropometric variables of the nasal region analysed had not suffered any significant variation. No significant differences were found when comparing T2 with T3 measures. No significant complications were found.

CONCLUSION

The results indicated that maxillary advancement using a subnasal modified Le Fort I osteotomy can prevent undesirable soft tissue changes of the nose when anterior repositioning of the maxilla is indicated in patients with preoperatively normal nasal morphology.

Three-dimensional soft-tissue and hard-tissue changes in the treatment of bimaxillary protrusion

INTRODUCTION

Facial convexity related to bimaxillary protrusion is prevalent in many populations. Underlying skeletal protrusion combined with increased dentoalveolar protrusion contributes to facial muscle imbalance and lip incompetence, which is undesirable for many patients. In this study, we evaluated the relationship between soft-tissue and hard-tissue changes in an orthodontically treated Asian population.

METHODS

Twenty-four consecutive adult Asian patients (mean age, 24 years), diagnosed with severe bimaxillary dentoalveolar protrusion, were evaluated using pretreatment and posttreatment cone-beam computed tomography. The patients were treated with 4 first premolar extractions followed by anterior retraction with either skeletal or intraoral anchorage. Serial cone-beam computed tomography radiographs were registered on the entire cranial base and fossa. Soft-tissue and hard-tissue changes were determined through landmark displacement and color mapping.

RESULTS

Upper lip retraction was concentrated between the nasolabial folds and commissures. Lower lip retraction was accompanied by significant redistribution of soft tissues at pogonion. Soft-tissue changes correlated well with regional facial muscle activity. Significant retractions (2-4 mm) of the soft tissues occurred beyond the midsagittal region. Use of skeletal anchorage resulted in 1.5 mm greater lower lip retraction than intraoral anchorage, with greater retraction of the maxillary and mandibular incisor root apices.

CONCLUSIONS

Profound soft-tissue changes accompanied retraction of the anterior dentition with both treatment modalities.