Assessment of facial symmetry by three-dimensional stereophotogrammetry after mandibular reconstruction: A comparison with subjective assessment

Quantifying Dermatochalasis Using 3-Dimensional Photogrammetry

BACKGROUND

Creating an appropriate treatment plan for patients with dermatochalasis requires careful investigation of the periocular region. Utilizing photographic documentation can assist physicians in conducting preoperative analysis and managing expectations regarding surgical outcomes.

OBJECTIVES

This study aimed to quantify the periocular characteristics of dermatochalasis patients using standardized 3D imaging and to compare age and sex-related changes in periocular features.

METHODS

In this cross-sectional study, we recruited 145 Caucasian patients with periocular dermatochalasis, comprising 48 men and 97 women, aged between 35 and 91 years. Standardized three-dimensional facial photographs were taken using the 3D Imaging system VECTRA M3. Linear dimensions, curve length, angle, indices, and sizes were measured and analyzed, including palpebral fissure height (PFH), palpebral fissure width (PFW), upper lid fold-palpebral margin distance (FPD), upper palpebral margin length (UPML), lower palpebral margin length (LPML), canthal tilt (CT), palpebral fissure index (PFI), upper eyelid area, and ocular surface area.

RESULTS

In the female group, the left-side PFH was slightly larger than the right-side PFH (P = 0.023), but the difference was less than 1mm. The corresponding PFI also showed a difference in the female group (P = 0.009). Statistically significant differences were shown in genders for specific parameters, except PFI (P = 0.251) and CT (P = 0.098). Among males, PFW (R = -0.523, p < 0.001) and LPML (R = -0.514, P = 0.264) decreased moderately with age. The correlation between UPML and age was weak (R = -0.367, P = 0.010). Similarly, among females, moderate correlations were found between age and PFW (R = -0.566, P < 0.001) and LPML (R = -0.537, P < 0.001). Additionally, PFH (R = -0.315, P = 0.002), UPML (R = -0.381, P < 0.001), and ocular surface area (R = -0.457, P < 0.001) showed weak correlations with age.

CONCLUSIONS

The study found that dermatochalasis usually affects both eyes simultaneously, and age is a significant factor in the morphological changes of certain periocular features regardless of sex. The PFI is not influenced by age or sex. These findings may provide useful information for surgical planning and understanding age-related changes in the periocular area.

LEVEL OF EVIDENCE V

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 .

Aesthetic Reconstruction of Onco-surgical Mandibular Defects Using Free Fibular Flap with and without CAD/CAM Customized Osteotomy Guide: A Randomized Controlled Clinical Trial

BACKGROUND

Reconstruction of mandibular defects following ablative surgery remains a challenge even for experienced surgeons. Virtual planning and guided surgery, including computer-aided design/computer-aided manufacturing (CAD/CAM), afford optimized ways by which to plan complex surgery. This study aimed to evaluate and compare aesthetic outcome and surgical efficiency of free fibular flap (FFF) with and without CAD/CAM customized osteotomy guide (COG) for reconstruction of onco-surgical mandibular defects.

METHODS

Twenty-two patients indicated for segmental mandibulectomy were randomly assigned to either CAD/CAM with COG group or that without COG- Model based reconstruction (MB group) at a 1:1 ratio. Aesthetic outcomes were evaluated by means of morphometric assessment and comparison for each differential area (DAr) and angle (DAn) in the affected side to the contralateral side of the mandible using computerized digital imaging analysis (CDIA) based on the post-operative 3D CT-scan. Subjective evaluation was performed using the Visual Analogue Scale (VAS) and Patient's Satisfaction Score (PSS). Surgical efficiency was a secondary outcome and evaluated as total operative time and ischemia time.

RESULTS

The mean sagittal DAr was significantly lower in the COG group (277.28 ± 127.05 vs. 398.67 ± 139.10 mm², P = 0.045). Although there was an improvement in the axial DAr (147.61 ± 55.42 vs. 183.68 ± 72.85 mm²), the difference was not statistically significant (P = 0.206). The mean differences (Δ) in both sagittal and coronal DAn were significantly lower in the COG group than in the MB group (6.11 ± 3.46 and 1.77 ± 1.12° vs. 9.53 ± 4.17 and 3.44 ± 2.34°), respectively. There were no statistically significant differences in the axial DAn between the two groups (P = 0.386). The PSS was significantly higher in the COG group, reflecting better aesthetic satisfaction than in the MB group (P = 0.041). The total operation and ischemia time were significantly shorter in favor of the COG group with a mean of (562.91 ± 51.22, 97.55 ± 16.80 min vs. 663.55 ± 53.43, 172.45 ± 21.87 min), respectively.

CONCLUSION

The CAD/CAM with COG is more reliable and highly valuable in enhancing aesthetic outcomes and surgical efficiency of mandibular reconstruction by FFF compared to that without COG (MB reconstruction).

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov .

REGISTRATION NUMBER

NCT03757273. Registration date: 28/11/2018.

Validation of Vectra 3D Imaging Systems: A Review

Aim: Three-dimensional facial imaging systems are a useful tool that is gradually replacing two-dimensional imaging and traditional anthropometry with calipers. In this varied and growing landscape of new devices, Canfield (Canfield Scientific, Parsippany, NJ, USA) has proposed a series of static and portable 3D imaging systems. The aim of this systematic review was to evaluate the current literature regarding the validation of Canfield’s Vectra imaging systems. Materials and Methods: A search strategy was developed on electronic databases including PubMed, Web of Science and Scopus by using specific keywords. After the study selection phase, a total of 10 articles were included in the present review. Results: A total of 10 articles were finally included in the present review. For six articles, we conducted a validation of the Vectra static devices, focusing especially on the Vectra M5, Vectra M3 and Vectra XT. For four articles, we validated the Vectra H1 portable system. Conclusions: All of the reviewed articles concluded that Canfield’s Vectra 3D imaging systems are capable of capturing accurate and reproducible stereophotogrammetric images. Minor errors were reported, particularly in the acquisition of the perioral region, but all the evaluated devices are considered to be valid and accurate tools for clinicians.

Mandibular shape prediction model using machine learning techniques

OBJECTIVE

To create a mandibular shape prediction model using machine learning techniques and geometric morphometrics.

MATERIALS AND METHODS

Six hundred twenty-nine radiographs were used to select the most appropriate craniomaxillary variables in different craniofacial pattern classifications using a support vector machine. To obtain the three-dimensional mandibular shape, a Procrustes fit was used on 55 tomograms, in which 17 three-dimensional landmarks were digitized. A partial least square regression was employed to find the best covariation between craniomaxillary angles and the symmetric components of mandibular shape. The model was applied to a new sample of six tomograms and evaluated by the mean absolute error. Each mandible predicted was assessed using the Hausdorff distance (HDu) and a color scale. The model was also exploratively applied to six new radiographs.

RESULTS

Covariation was 88.66% with a significance of < 0.0001 explained by twelve craniomaxillary variables. Low differences between the original and predicted models were obtained, with a mean absolute error of 0.0143. The mean distance between meshes ranged from 0.0033 to 0.0059 HDu and each color scale demonstrated general similarity between the surfaces.

CONCLUSIONS

This approach offered promising results in obtaining a mandibular prediction model that enhances shape properties in an economical way and is applicable to a Latin American population. Clinical proof of this method will require further studies with larger samples.

CLINICAL RELEVANCE

This method offers a reliable, economic alternative to traditional mandibular prediction methods and is applicable to the Latin American population.

Analysis of hard tissue facial symmetry after unilateral mandibular reconstruction

Background

This study aimed to determine how successful reconstruction of the mandible can recover the symmetry.

Materials and methods

All patients who underwent surgical treatment for unilateral mandibular reconstruction in 4 years were retrospectively examined. Bilateral differences of gonion (GO) positions were measured in 3 dimensions based on immediate postoperative computed tomography. The data collected was analyzed in 3 ways: First, the comparison of bilateral differences of GO in 3 dimensions. Second, the mean Asymmetry Index in control subjects was used to divide all cases into three groups: “Symmetry,” “Asymmetry,” and “Marked asymmetry.” Third, “maximum normal asymmetry” was calculated, and all cases were categorized as below and above maximum normal asymmetry. The difference between two gonial angles was used to determine the amount of asymmetry.

Results

Forty-seven patients and 47 normal adults were enrolled. The mean bilateral GO difference in the control group was higher than in the study group patients, but it was not statistically significant. The mean Asymmetry Index for the control group was not also significantly higher than the study cases. The study group was “Symmetric” in 78.7% of the cases whereas the control group in 91.4%, 19.1% of the study group and 8.5% of controls were “Asymmetric,” and 2.1% of study cases and 0% of controls were “Markedly Asymmetric.” Maximum normal asymmetry was 82.9% in the study group and 97.8% in the control group. The mean differences between the right and left gonial angles were higher in the study group, but it was not significant (P = 0.1).

Conclusions

Our study’s results showed that bilateral symmetry in mandibular reconstruction patients was satisfactory and similar to the normal individuals.

Thread lifting of the midface: A pilot study for quantitative evaluation

Volume restoration remains the principal target to be addressed when approaching midface rejuvenation, and absorbable sutures can create a suspension system that addresses ptotic skin located primarily in the midface. The aim of this pilot study was to investigate the effectiveness in lifting sagging tissue and to determine the outcome of thread lifting procedures of the midface. Six participants were enrolled and treated with suspension threads to correct mild to moderate ptosis of the flabby tissues of the midface. Volumetric changes were calculated at t0 (pretreatment), t1(120 days) and t2 (365 days), with a mean follow-up time of 349.64 days, (range from 304 to 380.5 days). Results showed an overall average improvement of 5.59 mL at 120 days (t0-t1) after thread implantation, up to a mean value of 4.16 mL at the end of the 350 days follow up (t0-t2). A comparison was made in between and statistical analysis was performed with level of significance set at P < .05. The records shown suggest that it is possible to achieve volume restoration which lasts up to 12 months as all parameters improved significantly (P < .05) at t1 and at t2 with respect to t0. Facial tissues suspension by means of threads is therefore safe and effective, as it is possible to achieve tissue repositioning which lasts up to 12 months for the correction of mild to moderate ptosis of the midface.