Method selection in craniofacial measurements: advantages and disadvantages of 3D digitization method

Photography in orthognathic surgery: A standardized protocol and storage legal implications

Medical photography is an essential tool in orthognathic surgery to facilitate diagnosis, preoperative planning, and follow-up. Photographic documentation has clinical, research, teaching and legal applications. An accurate diagnostic approach and surgical planning of dentofacial deformity requires the ability to work with reproducible and measurable photographic images. It must also respect certain legislative rules for its use within a health institution and the dissemination of images in the educational and scientific framework. We propose through this narrative review a standardized protocol to obtain reproducible images in the different planes of space. We also review and discuss fundamental points for setting up a photographic room dedicated to photography in orthognathic surgery.

External Ear Anthropometry of Healthy Turkish Young Adults

PURPOSE

The aim of this study was to determine the external ear values in Turkish young adults with 2-dimensional photogrammetry.

METHODS

One hundred males and 100 females aged between 18 and 25 years were included in the study. Individuals were photographed from both sides. Ear length (superaurel-subaurel, spa-sba ), ear width (preaurel-postaurel, pra-pa ), and the angle between the vertical axis of the auricle and the line between spa and sba (ear incline angle, eia ) were measured in these photographs. Also, auricular index ( pra-pa / spa-sba ×100) was calculated.

RESULTS

The average values of the spa-sba, pra-pa , eia , and auricular index were found as 65.46±4.68 mm, 37.89±3.61 mm, 19.40±4.83 degrees, and 57.93±4.53 in males and 60.90±5.35 mm, 35.62±3.69 mm, 17.95±4.86 degrees, and 58.65±5.29 in females, respectively. While the values of spa-sba ( P =0.001 for the right side and P =0.001 for the left side), pra-pa ( P =0.001 for the right side and P =0.001 for the left side), and eia ( P =0.024 for the right side and P =0.041 for the left side) were statistically higher for males than females, there was no statistically significant difference between the sex and the auricular index ( P =0.404 for the right side and P =0.955 for the left side). Besides, there was no statistically significant difference between the sides for these 4 parameters ( P =0.760, 0.409, 0.225, and 0.521, respectively).

CONCLUSION

The authors believe that the results obtained for Turkish young adults can be used as reference values, which can be used in the diagnosis, follow, or surgical treatment of many diseases, forensic procedures, and planning esthetic surgery procedures.

Integration accuracy of craniofacial cone-beam computed tomography images with three-dimensional facial scans according to different registration areas

OBJECTIVES

To evaluate the integration accuracy of cone-beam computed tomography (CBCT) images with three-dimensional (3D) facial scans according to different registration areas.

MATERIALS AND METHODS

Twenty-five patients (14 males and 11 females), with a mean age of 19.0 ± 11.3 years, were included in this study. Each patient underwent CBCT and facial scans on the same day in an upright position. The facial scans were integrated with the corresponding soft-tissue images of CBCT scans. Three methods were used to integrate the two imaging modalities based on the facial regions scanned: R1, only the forehead and nasal bridge area were included; R2, the right and left malar area were included; and R3, the forehead, nasal bridge, and malar areas were included. The integration accuracy between the facial scans and CBCT images was evaluated by color-mapping methods and average surface distances, calculated by measuring the 3D distances between the surface points on the two superimposed images.

RESULTS

The average surface differences between facial scans and CBCT images were less than 1.0 mm in all three methods. The R3 method showed fewer differences between the facial scans and CBCT images than the other methods did.

CONCLUSIONS

Facial scans obtained using a low-cost facial scanner showed clinically acceptable performance. The integration accuracy of facial and CBCT scans can be increased by including the forehead, nasal bridge, and malar areas as registration areas.

Cloner 3D photogrammetric facial scanner: Assessment of accuracy in a controlled clinical study

OBJECTIVE

To evaluate the accuracy of facial measurements on three-dimensional images obtained using a new photogrammetric scanner.

MATERIAL AND METHODS

A total of 11 participants were included in the study. Nine customized adhesive labels were used to identify the facial landmarks: Trichion (Tri), Glabella (G), Right (Exr) and Left (Exl), Pronasal (Pn), Subnasal (Sn), Chelion right (Chr) and left (Chl) and Mentonian (Me). Two trained and calibrated examiners were responsible for performing seven linear measurements for each participant (Tri-G, Sn-Me, Exr-Exl, Chr-Chl, Exr-Chr, Exl-Chl, Pn-Sn) first with a digital caliper and later with a three-dimensional model obtained after digitalization with photogrammetric technology. The intraclass correlation coefficient (ICC), mean difference, SD, and Bland-Altman correlation were used to compare the measurements performed.

RESULTS

Intra and inter-examiner reliability were excellent (ICC >0.9). In general, the measurements presented a variation of a minor 2.0 mm. However, only three measures (Sn-Me, Exr-Exl, and Exr-Chr) were outside the clinical acceptability range.

CONCLUSIONS

The 3D Cloner scanner showed clinically acceptable accuracy comparable to the digital caliper with a variation of -0.8 ± 1.2 mm. Inter- and intra-examiner agreement on digital measurements was also observed.

CLINICAL SIGNIFICANCE

Scanners with accurate 3D model reproductions associated with reliable digital measurements provide a more precise diagnosis and better planning in orofacial treatment.

Anthropometric Comparison of 3-Dimensional Facial Scan Taken With a Low-Cost Facial Scanner With Cone-Beam Computed Tomography Scan

OBJECTIVE

The aim of this study was to evaluate the accuracy of 3-dimensional (3D) facial scans taken with a low-cost facial scanner compared with cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Twenty-five patients had their CBCT scan and 3D facial scan taken on the same day. Facial scans were taken with a low-cost facial scanner (Bellus3D, ARC-1 scanner) in an upright position. The facial scans were imported into Invivo5 software and were integrated with the corresponding CBCT scans. Then, 16 soft tissue landmarks were identified on the CBCT scans and the 3D-integrated facial scans. The 6 vertical, 7 horizontal, 10 oblique linear, and 11 angular anthropometric measurements were obtained and compared between the CBCT scans and 3D-integrated facial scans using paired t test and Bland-Altman plots.

RESULTS

The differences between CBCT scans and 3D-integrated facial scans showed no statistical significance except for 2 vertical measurements. Bland-Altman plots showed that all anthropometric measurements were within the limit of agreement. The differences between CBCT scans and 3D-integrated facial scans were <1.5 mm or 1.5 degrees except for 2 vertical measurements.

CONCLUSIONS

Three-dimensional facial scans taken with facial scanner showed a clinical acceptance when compared with CBCT scans.

The Vectra M3 3-dimensional digital stereophotogrammetry system: A reliable technique for detecting chin asymmetry

Purpose

The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks.

Materials and Methods

Twenty subjects (18 females and 2 males) with a mean age of 42.5±10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra- and inter-examiner reliability.

Results

No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P=0.783 and P=0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks.

Conclusion

The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra® M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.

Establishment of a finite element model based on craniofacial soft tissue thickness measurements and stress analysis of medical goggles

In this study, an accurate finite element (FE) stress analysis of head-mounted products for Chinese users was performed. Using craniofacial computed tomography scans of 280 Chinese individuals, the total soft tissue thickness and thickness of the fat and muscle layers for 41 landmarks were measured. The data were used to construct FE head models (FEH). An FE stress test was conducted to analyse the wearing of medical goggles using two FE models based on one-layer (FEH 1) and three-layer (FEH 3) soft tissue material parameters. When compared with the experimental results, the modelling results for FEH 3 were more realistic than those for FEH 1. Wearing medical goggles led to stress concentration over five landmark areas, A: upper medial forehead, B: temporal, C: zygion, D: infraorbital fossa and E: rhinion, of which B, C and D caused the most discomfort during long-term goggle wear. Practitioner summary: A precise FE head model can reflect the complex contact pressure of a head-related product. Two FE models based on one- and three-layer soft tissue material parameters were established and tested separately with medical goggles. The model can be used to improve the comfort of head-related products. Abbreviations: FE: finite element; FEH: FE head models; FEH 1: FE models based on one-layer; FEH 3: FE models based on three-layer; VR: virtual reality; AR: augmented reality; 3D: three-dimensional; WSU: Wayne State University; WSUBIM: Wayne State University Brain Injury Model; CT: computed tomography; MRI: magnetic resonance imaging; CFSTT: craniofacial soft tissue thickness; FSR: force sensing resistor; NURBS: non-uniform rational basis spline; SPSS: statistical product and service solutions; STL: stereolithography; STP: standard for the exchange of product model data; BDF: glyph bitmap distribution format; EEG: electroencephalogram.

Longitudinal composite 3D faces and facial growth trends in children 6-11 years of age using 3D cephalometric surface imaging

BACKGROUND

Normative craniofacial anthropometry provides clinically important reference values used in the treatment of craniofacial conditions. Few objective datasets of normative data exist for children.

AIM

To establish normative data regarding craniofacial morphology changes with growth in children.

SUBJECTS AND METHODS

3D surface images of the same group of healthy children aged 6 - 11 years old recruited from a Dallas school were taken annually between the years 2015 - 2020. Composite 3D cephalometric faces were created for boys and girls of each age. General and craniofacial anthropometric measurements were compared.

RESULTS

Seven hundred ninety one individual stereophotogrammetric acquisitions were used (400 boys, 391 girls) taken from 180 children. Linear facial, orbital, nasal, and oral anthropometric measurements revealed a consistent increase in magnitude with age. Composite 3D face comparisons revealed prominent vertical and anteroposterior growth trends in the lower and upper facial regions.

CONCLUSION

This study presents a longitudinal 3D control dataset of the same group of children over a 6-year period that can serve as reference norms for facial growth values and trends in children aged 6-11 years. The composite 3D normative faces are available for clinical and research purposes upon request, which may be interrogated and measured according to user need and preference.

Three-dimensional objective evaluation of facial palsy and follow-up of recovery with a handheld scanner

BACKGROUND

Clinicians need accurate, reproducible, fast, and cost-effective grading systems to determine facial functions. There is currently no internationally accepted objective method to report the loss of function at the onset of facial paralysis and subsequent recovery. Our study aimed to test a three-dimensional handheld light scanner's efficacy for grading facial paralysis and monitoring recovery.

METHODS

Sixty-one healthy volunteers (28 men and 33 women) aged between 20 and 75 years (mean 36.4 ± 11.9 years old) and 22 patients with facial palsy (10 male and 12 female patients) aged between 12 and 77 years (mean 47.6 ± 19.7 years old) were included in the study. The healthy individuals' and patients' facial scans were performed with a three-dimensional handheld scanner during different facial expressions at 3-month intervals. The asymmetry and intensity degree of each facial expression were determined in terms of the root mean square.

RESULTS

After facial paralysis, a significant larger asymmetry value (1.2 ± 0.4 mm vs. 2.0 ± 0.8 mm and p<0.05) was determined as compared to the control group, while a significant smaller intensity value (2.3 ± 1.2 mm vs. 1.7 ± 0.9 mm and p<0.05) was observed. At the end of 3 months, both parameters showed a tendency to recover.

CONCLUSION

Our findings suggest that three-dimensional morphological analyses may be an effective method to grade facial palsy. However, our data need to be confirmed by larger cohort size and more extended follow-up periods.

Craniofacial Anthropometry of Healthy Turkish Young Adults: Analysis of Head and Face

ABSTRACT

The aim of this study was to evaluate the craniofacial anthropometric measurements of Turkish young adults between the ages of 18 and 25. Anterior view and side profile photographs were taken of 100 females and 100 males who volunteered to participate in the study and had no craniofacial anomalies, history of facial trauma, or history of orofacial surgery. Thirteen landmarks on the face and head were chosen, and these landmarks were identified on the photographs. Then, using these landmarks, a total of 19 distance measurements were made, 16 from the anterior view, and 3 from the side profile. There were statistically significant differences between the sexes in 13 parameters: 2 parameters (t-n and ft-ft) being higher in females and 11 parameters (v-n, v-t, t-gn, sn-gn, n-gn, st-gn, sl-gn, fz-fz, z-z, tr-tr and go-go) being higher in males. Also, 7 facial anthropometric ratios were calculated. There were statistically significant differences between the genders in all ratios. The literature reveals that craniofacial anthropometric measurements have been performed on many different populations and that there are numerous differences between the results of the studies conducted. We are of the opinion that the results obtained in this present study will contribute to the literature by helping to determine the standard values for the Turkish population between the ages of 18 and 25, which can be used in diagnosis, treatment and postoperative evaluation in areas such as forensic science, orthodontics, clinical genetics, maxillofacial surgery, and plastic surgery.

Craniofacial Anthropometry of Healthy Turkish Young Adults: Outer Canthal, Inner Canthal, Palpebral Fissure, and Interpupillary Distances

ABSTRACT

This study aims to examine the values of the orbital region in Turkish young adults by the two-dimensional photogrammetry. Anthropometric measurements of the eye and eyelid-related parameters were taken from 100 female and 100 male volunteer Turkish young adults, ranging in age from 18 to 25 years. Endocanthion (en), exocanthion (ex), and pupil (p) were identified on the photograph and the distances between these points were measured with the ImageJ program. The average values of the en-en, ex-en (R), ex-en (L), p-p, and ex-ex were found as 32.92 ± 2.84, 32.48 ± 2.06, 32.22 ± 2.01, 65.32 ± 3.77, and 97.75 ± 5.09 mm, respectively. There were statistically significant differences between the genders in all parameters. Although there are many studies examining these parameters, comprehensive studies are needed in different populations and in many cases. In this study, we believe that the results obtained for Turkish young adults can be used as reference values.

Reliability of optical devices for three-dimensional facial anatomy description: a systematic review and meta-analysis

The use of three-dimensional (3D) optical instruments to measure soft tissue facial characteristics is increasing, but systematic assessments of their reliability, practical use in research and clinics, outcome measurements, and advantages and limitations are not fully established. Therefore, a review of the current literature was performed on the reliability of facial anthropometric measurements obtained by 3D optical facial reproductions as compared to conventional anthropometry or other optical devices. The systematic literature search was conducted in electronic databases following the PRISMA guidelines (PROSPERO registration: CRD42018085473). Overall, 815 studies were identified, with 27 final papers included. Two meta-analyses were conducted. Tested devices included conventional cameras, laser scanning, stereophotogrammetry, and structured light. Studies measured living people or inanimate objects. Overall, the optical devices were considered reliable for the measurement of linear distances. Some caution is needed for surface assessments. All instruments are suitable for the analysis of inanimate objects, but fast scan devices should be preferred for living subjects to avoid motion artefacts in the orbital and nasolabial areas. Prior facial landmarking is suggested to improve measurement accuracy. Practical needs and economic means should direct the choice of the most appropriate instrument. Considering the increasing interest in surface-to-surface measurements, fast scan devices should be preferred, and dedicated protocols devised.

Reliability of periocular anthropometry using three-dimensional digital stereophotogrammetry

PURPOSE

Non-invasive three-dimensional (3D) stereophotogrammetry is becoming increasingly popular in many fields. However, few studies have focused on its periocular application. We aimed to provide evidence for the periocular application of a novel anthropometric procedure using 3D stereophotogrammetry by evaluating its reliability.

METHODS

Fifty-one Caucasians were recruited (102 eyes; mean age, 31.9 ± 13.6 years). Two sets of 3D images were acquired for each subject, and two measurement sessions were performed on each image by two raters. Fifty-two periocular landmarks were identified, and then 49 corresponding linear, curvilinear, and angular measurements were evaluated for intrarater, interrater, and intramethod reliability.

RESULTS

Our findings showed highly reliable results for mean absolute difference (0.59 and 0.68 unit), relative error measurement (2.66% and 3.08%), technical error of measurement (0.59 and 0.66 unit), relative technical error of measurement (2.71% and 2.96%), and intraclass correlation coefficient (0.98) for intrarater 1 and intrarater 2 reliability; respectively 0.94 unit, 4.06%, 0.89 unit, and 3.94%, as well as 0.97 for interrater reliability; and respectively 0.98 unit, 4.66%, 0.96 unit, and 4.64%, as well as 0.96 for intramethod reliability.

CONCLUSIONS

This imaging system and the landmark identification protocol are highly reliable. The collected measurements and their errors can be applied for the comparison of reliability among various 3D imaging systems and populations. It could be utilized for planning surgeries and evaluating treatment outcomes for physicians in ophthalmology, plastic and esthetic surgery, and in the maxillofacial field where periocular morphology alterations are made.

Scan time, reliability and accuracy of craniofacial measurements using a 3D light scanner

Aim

To evaluate time, reliability and accuracy of craniofacial measurements with a 3D light scanner, considering prior demarcation of surface points on the face.

Materials and methods

Eleven facial measurements of 15 volunteers were obtained by a scanner (Artec Eva TM) and by a caliper directly on the face, with or without demarcation of facial reference points. Inter and intra-method comparison were examined by intraclass correlation coefficient and analysis of random error by the Dahlberg formula. Agreement between the methods was analyzed by the Bland-Altman. A Wilcoxon test was used to compare the time for each method, at p < 0.05.

Results

Marking points on the face improved accuracy for both methods. In the inter-methods analysis with landmarks, the scanner showed excellent reliability in all measures (ICC = 0.92-0.97, p < 0.0001). Measurements accuracy with scanner was around 2 mm when the points were not previously marked and about 1 mm when the points were marked. Measures taken with the scanner, however, took twice as long, compared with the direct method.

Conclusions

Craniofacial measurements obtained with scanner showed excellent reliability and accuracy, which qualifies this method for clinical and scientific use. Accuracy is improved when the points were previously marked on face. However, the time needed to obtain measurements is greater than about 4 min for the direct method.

High-Fidelity Anthropometric Facial Measurements Can Be Obtained From a Single Stereophotograph From the Vectra H1 3-Dimensional Camera

BACKGROUND

Anthropometry is a well-established means of measuring facial morphology. Although reliable, direct anthropometry can be time-consuming and not conducive to a busy clinical practice. The Vectra H1 handheld stereophotogrammetric system requires 3 stereophotographs taken from different perspectives to generate a three-dimensional (3D) surface. The time needed to take the 3 stereophotographs can increase the possibility of involuntary movements, precluding its use to assess young patients. To overcome this limitation, we evaluated if accurate linear facial measurements can be obtained from a single stereophotograph and compare these to the measurements taken by direct anthropometry.

METHODS

Twenty pediatric patients, aged 0 to 10 years, who were undergoing minor surgical procedures at Johns Hopkins All Children's Hospital were recruited. Fourteen linear facial distances were obtained from each participant using direct anthropometry under general anesthesia. These same distances were measured using Mirror 3D analysis. Intraclass correlation was used to determine intrarater reliability on duplicate 3D images.

RESULTS

Correlation coefficients between 3D imaging in frontal view and direct anthropometric measurements were excellent for 13 measures taken, ranging from 0.8 (subnasale to columella and subnasale to stomion superius) to 0.98 (nasion to subnasale and subnasale to labiale superius). Correlation coefficients between submental view and direct anthropometric measurements were excellent for 13 measures as well, ranging from 0.77 (subnasale to columella) to 0.98 (nasion to subnasale).

CONCLUSIONS

Linear anthropometric measurements taken from 3D surfaces generated from a single stereophotograph correlate closely with direct anthropometric measures. This improves workflow and applicability of anthropometric studies to our youngest patients.

Validation of a low-cost portable 3-dimensional face scanner

Purpose

The goal of this study was to assess the accuracy and reliability of a low-cost portable scanner (Scanify) for imaging facial casts compared to a previously validated portable digital stereophotogrammetry device (Vectra H1). This in vitro study was performed using 2 facial casts obtained by recording impressions of the authors, at King's College London Academic Centre of Reconstructive Science.

Materials and Methods

The casts were marked with anthropometric landmarks, then digitised using Scanify and Vectra H1. Computed tomography (CT) scans of the same casts were performed to verify the validation of Vectra H1. The 3-dimensional (3D) images acquired with each device were compared using linear measurements and 3D surface analysis software.

Results

Overall, 91% of the linear Scanify measurements were within 1 mm of the corresponding reference values. The mean overall surface difference between the Scanify and Vectra images was <0.3 mm. Significant differences were detected in depth measurements. Merging multiple Scanify images produced significantly greater registration error.

Conclusion

Scanify is a very low-cost device that could have clinical applications for facial imaging if imaging errors could be corrected by a future software update or hardware revision.

Human Facial Shape and Size Heritability and Genetic Correlations

The human face is an array of variable physical features that together make each of us unique and distinguishable. Striking familial facial similarities underscore a genetic component, but little is known of the genes that underlie facial shape differences. Numerous studies have estimated facial shape heritability using various methods. Here, we used advanced three-dimensional imaging technology and quantitative human genetics analysis to estimate narrow-sense heritability, heritability explained by common genetic variation, and pairwise genetic correlations of 38 measures of facial shape and size in normal African Bantu children from Tanzania. Specifically, we fit a linear mixed model of genetic relatedness between close and distant relatives to jointly estimate variance components that correspond to heritability explained by genome-wide common genetic variation and variance explained by uncaptured genetic variation, the sum representing total narrow-sense heritability. Our significant estimates for narrow-sense heritability of specific facial traits range from 28 to 67%, with horizontal measures being slightly more heritable than vertical or depth measures. Furthermore, for over half of facial traits, >90% of narrow-sense heritability can be explained by common genetic variation. We also find high absolute genetic correlation between most traits, indicating large overlap in underlying genetic loci. Not surprisingly, traits measured in the same physical orientation (i.e., both horizontal or both vertical) have high positive genetic correlations, whereas traits in opposite orientations have high negative correlations. The complex genetic architecture of facial shape informs our understanding of the intricate relationships among different facial features as well as overall facial development.

Ergonomic evaluation of biomechanical hand function

The human hand is a complex structure that performs various functions for activities of daily living and occupations. This paper presents a literature review on the methodologies used to evaluate hand functions from a biomechanics standpoint, including anthropometry, kinematics, kinetics, and electromyography (EMG). Anthropometry describes the dimensions and measurements of the hand. Kinematics includes hand movements and the range of motion of finger joints. Kinetics includes hand models for tendon and joint force analysis. EMG is used on hand muscles associated with hand functions and with signal-processing technology.

Three-dimensional mapping and comparative analysis of the distal human corpus cavernosum and the inflatable penile prosthesis

The intricate anatomy of the corpus cavernosum in both the flaccid and tumescent state has not been fully elucidated. We report our experience using a three-dimensional (3D) scanner to reconstruct cadaveric casts and compare them with 3D images of two prototypes of penile prosthesis. Two different models of the Titan Coloplast inflatable penile prosthesis were analyzed using a 3D scanner. The first was the standard model and the second was a newer model with a rounder silicone tip. Two cadaveric phalluses were harvested using Smooth-Cast 300Q polyurethane molding. The molds were excised and scanned along side the penile prosthesis. 3D scans were completed and analyzed using Leios Mesh software, and GOM Inspect software. The 3D scans demonstrated the mean human corporal radii 2 mm from the distal tip to be 36.51 mm (36.01-37.0 mm), which is an obtuse angle. The standard Titan penile prosthesis spherical radius at the same level was 202.52 mm, while the new silicone tip prosthesis had a radius of 139.33 mm. 3D mapping further demonstrated the trajectory of the cavernosa appeared curvilinear and the distal ends appeared blunt. The use of cadaveric cavernosal molds in combination with the 3D scanner allowed us to accurately image the corpus cavernosum for the first time. Our findings suggest that anatomically accurate corporal tips appear to be relatively blunt and that the new Titan silicone tip penile prosthesis more closely resembles the human corporal tip.

Assessment of the usefulness of three-dimensional scanner in aesthetic evaluation of post-traumatic rhinoplasty

Preoperative, accurate measurement of spatial parameters of the external nose could be essential in the postoperative assessment of rhinoplasty. The aim of the study was to analyse the relevance of three-dimensional (3D) imaging in aesthetic evaluation after operation, to provide a standardised algorithm of nasal shape measurements, which will enable the development of software for assessing the nose before and after rhinoplasty, to perform analysis of spatial changes of both its shape and asymmetry by the new protocol of measurements. Fifty-four patients were examined preoperatively and 6 months postoperatively. The following nasal parameters were determined: rates of proportion, angles, and spatial parameters. After the operation, statistically significant differences were observed in all parameters. In conclusion, a 3D scanner can be used as a tool to assess the results of rhinoplasty. This protocol of measurements describes spatial changes of the nose shape resulting from the operation.

Oculopalpebral dimensions of adult Nigerians: report from the Enugu normative ocular anthropometry study

OBJECTIVE

To determine the normal oculopalpebral anthropometric measurements of a Nigerian adult population.

SUBJECTS AND METHODS

A population-based prospective observational random survey was conducted in Enugu, South-Eastern Nigeria between January and April 2010. The participants were healthy adults comprising 248 males and 252 females aged 18-76 years. One thousand eyes were examined. Demographic data, and bilateral direct manual millimetre measurements of the horizontal palpebral fissure (HPF), vertical palpebral fissure (VPF), upper lid crease (ULC), brow height (BH), and margin reflex distance (MRD) were obtained from all participants. Data were categorised by demographic variables and analysed to yield frequencies, percentages and proportions. Between-gender comparisons, using the independent t test, were considered significant at p < 0.05.

RESULTS

The mean age of the participants was 36.5 ± 14.6 years. There was no significant difference between the genders in mean age (men: 37.3 ± 15.7 vs. women: 35.8 ± 13.3, p = 0.2302). The mean values of the parameters were (male, female) HPF: 32.8 ± 2.0 vs. 32.6 ± 3.0; VPF: 10.6 ± 1.2 vs. 10.6 ± 1.2; ULC: 8.2 ± 2.5 vs. 7.9 ± 2.2; BH: 13.1 ± 2.4 vs. 13.6 ± 2.7; and MRD: 4.1 ± 0.5 vs. 4.2 ± 0.8. Significant between-gender difference was observed only in BH measurements (p = 0.029) and variable trends with age.

CONCLUSION

Oculopalpebral measurements of normal adult Nigerians in Enugu showed variations by age and gender. This may have implications for clinical evaluation and surgical management of oculopalpebral disorders in adult South-Eastern Nigerians. Future longitudinal studies are needed.

Piezoelectric device vs. conventional rotative instruments in impacted third molar surgery: relationships between surgical difficulty and postoperative pain with histological evaluations

PURPOSE

To investigate and compare the influence of surgical difficulty on postoperative pain after treatment of impacted mandibular third molars by rotatory osteotomy or Piezoelectric surgery.

MATERIALS AND METHODS

A prospective, randomized, split-mouth study was performed of 52 patients with bilateral and symmetrically oriented impacted mandibular third molars, who were surgically treated using a burr (Group A) on one random side of the lower jaw and a Piezoelectric device (Group B) on the contralateral side. Surgical difficulty was evaluated using a modified version of the Parant scale to categorize "simple extractions" and "complex extractions". Primary outcome parameters were the comparison of the postoperative pain evaluation rated on the Visual Analogue Scale from day 0 to day 6 postsurgery, and the assessment of differences in surgery time between the groups. Bone biopsies were taken during surgery to assess differences in bone tissue damage levels between the two different techniques.

RESULTS

In "complex extractions" lower pain evaluation and significantly shorter surgery times were recorded when rotatory instruments were used. In "simple extractions", similar surgery times were observed for both techniques, but pain was greatest on the day of surgery when the burr was used. Bone heat osteonecrosis was observed only in the rotatory group and a high level of alkaline phosphatase was noted only in the Piezoelectric group.

CONCLUSION

Pain after extraction of a mandibular third molar increases with increased surgical difficulty and especially in longer interventions. The integrity of the bony structure observed after the ultrasonic technique may favour the bone healing process.

A novel prospective three-dimensional analysis of nasolabial fold augmentation

BACKGROUND

There are many products approved for aesthetic soft tissue augmentation. Despite this abundance, there is limited objective data regarding safety, longevity, and complication rates. Instead, most reports rely on subjective measures to report volume changes and outcomes, making product comparison difficult.

OBJECTIVES

The authors developed and validated a mathematical model to prospectively calculate and analyze three-dimensional (3D) volumetric changes associated with nasolabial fold augmentation based on human acellular dermis.

METHODS

Seven consecutive patients were included in this prospective review. The patients underwent nasolabial fold treatment with BellaDerm (Musculoskeletal Transplant Foundation, Edison, NJ), administered by a single surgeon. 3D photographs were obtained and analyzed with a novel mathematical model to determine absolute volumetric changes and objective longevity.

RESULTS

Mean preoperative nasolabial fold volume was 0.17 mL. The mean one-, three-, and six-month postoperative fill volumes were 0.35, 0.19, and 0.07 mL, respectively. Fill volumes and contour changes returned to baseline by 24 weeks postoperatively in the majority of patients.

CONCLUSIONS

The mathematical model utilized in this study provided prospective and objective data regarding longevity and volumetric changes associated with nasolabial fold augmentation. The analysis demonstrated minimal objective filler permanence beyond six months, with peak volume enhancement between one and three months. Adoption of objective 3D mathematical metrics into the assessment of soft tissue filler outcomes is critical to obtaining more accurate product-to-product comparisons.

Evaluation of nasal reconstruction procedures results

Before undergoing a reconstructive procedures of the nose most patients ask how they will look postoperatively. Anthropometric measurements of the nose described by Farkas represent standard values. A comparison of pre- and postoperative anthropometric measurements may help to double-check the correctness of intraoperative "eye-balling" measurements with regards to postoperative appearance. Sixty-three patients underwent reconstruction of nasal ala, tip or dorsum. An analysis of standardized pre- and postoperative photographs included measurements of nose width, nose height, nasal tip protrusion, columella width, ala length, intercanthal width, mouth width, philtrum width, upper lip height, lateral upper lip height, cutaneous upper lip height and upper face height. Preoperative measurements were compared to data given by Farkas in young adults. Postoperative changes were evaluated clearly distinguishing between reconstruction of nasal ala, tip and dorsum. All anthropometric indices showed significant differences compared to the Farkas population. There was no significant pre- to postoperative change in any reconstructed region observed, indicating adequate intraoperative measurements. The application of Farkas' anthropometric measurements described in this study showed reliable and objective results and can help to double-check the previous intraoperative measurements. The correct application of these surgical techniques leads to a satisfying and near to normal postoperative look of the patient.

The contribution of each anterior cruciate ligament bundle to the Lachman test

The clinical diagnosis of a partial tear of the anterior cruciate ligament (ACL) is still subject to debate. Little is known about the contribution of each ACL bundle during the Lachman test. We investigated this using six fresh-frozen cadaveric lower limbs. Screws were placed in the femora and tibiae as fixed landmarks for digitisation of the bone positions. The femur was secured horizontally in a clamp. A metal hook was screwed to the tibial tubercle and used to apply a load of 150 N directed anteroposteriorly to the tibia to simulate the Lachman test. The knees then received constant axial compression and 3D knee kinematic data were collected by digitising the screw head positions in 30° flexion under each test condition. Measurements of tibial translation and rotation were made, first with the ACL intact, then after sequential cutting of the ACL bundles, and finally after complete division of the ACL. Two-way analysis of variance analysis was performed.

During the Lachman test, in all knees and in all test conditions, lateral tibial translation exceeded that on the medial side. With an intact ACL, both anterior and lateral tibial landmarks translated significantly more than those on the medial side (p < 0.001). With sequential division of the ACL bundles, selective cutting of the posterolateral bundle (PLB) did not increase translation of any landmark compared with when the ACL remained intact. Cutting the anteromedial bundle (AMB) resulted in an increased anterior translation of all landmarks. Compared to the intact ACL, when the ACL was fully transected a significant increase in anterior translation of all landmarks occurred (p < 0.001). However, anterior tibial translation was almost identical after AMB or complete ACL division.

We found that the AMB confers its most significant contribution to tibial translation during the Lachman test, whereas the PLB has a negligible effect on anterior translation. Section of the PLB had a greater effect on increasing the internal rotation of the tibia than the AMB. However, its contribution of a mean of 2.8° amplitude remains low. The clinical relevance of our investigation suggests that, based on anterior tibial translation only, one cannot distinguish between a full ACL and an isolated AMB tear. Isolated PLB tears cannot be detected solely by the Lachman test, as this bundle probably contributes more resistance to the pivot shift.

Photographic protocol for image acquisition in craniofacial microsomia

Craniofacial microsomia (CFM) is a congenital condition associated with orbital, mandibular, ear, nerve, and soft tissue anomalies. We present a standardized, two-dimensional, digital photographic protocol designed to capture the common craniofacial features associated with CFM.

Orbital change following Le Fort III advancement in syndromic craniosynostosis: quantitative evaluation of orbital volume, infra-orbital rim and globe position

Patients with syndromic craniosynostosis suffering from shallow orbits due to midface hypoplasia can be treated with a Le Fort III advancement osteotomy. This study evaluates the influence of Le Fort III advancement on orbital volume, position of the infra-orbital rim and globe. In pre- and post-operative CT-scans of 18 syndromic craniosynostosis patients, segmentation of the left and right orbit was performed and the infra-orbital rim and globe were marked. By superimposing the pre- and post-operative scans and by creating a reference coordinate system, movements of the infra-orbital rim and globe were assessed. Orbital volume increased significantly, by 27.2% for the left and 28.4% for the right orbit. Significant anterior movements of the left infra-orbital rim of 12.0mm (SD 4.2) and right infra-orbital rim of 12.8mm (SD 4.9) were demonstrated. Significant medial movements of 1.7mm (SD 2.2) of the left globe and 1.5mm (SD 1.9) of the right globe were demonstrated. There was a significant correlation between anterior infra-orbital rim movement and the increase in orbital volume. Significant orbital volume increase has been demonstrated following Le Fort III advancement. The position of the infra-orbital rim was moved forward significantly, whereas the globe position remained relatively unaffected.

Assessment of soft tissue changes by cephalometry and two-dimensional photogrammetry in bilateral sagittal split ramus osteotomy cases

Objectives

We aimed to compare the standard methods of cephalometry and two-dimensional photogrammetry, to evaluate the reliability and accuracy of both methods.

Material and Methods

Twenty-six patients (mean age 25.5, standard deviation (SD) 5.2 years) with Class II relationship and 23 patients with Class III relationship (mean age 26.4, SD 4.7 years) who had undergone bilateral sagittal split ramus osteotomy were selected, with a median follow-up of 8 months between pre- and postsurgical evaluation. Pre- and postsurgical cephalograms and lateral photograms were traced and changes were recorded.

Results

Pre- and postsurgical measurements of hard tissue angles and distances revealed higher correlations with cephalometrically performed soft tissue measurements of facial convexity (Class II: N-PG, r = - 0.50, P = 0.047; Class III: ANB, r = 0.73, P = 0.005; NaPg , r = 0.71, P = 0.007;) and labiomental angle (Class II: SNB, r = 0.72, P = 0.002; ANB, r = - 0.72, P = 0.002; N-B, r = - 0.68, P = 0.004; ANS-Gn, r = 0.71, P = 0.002; Class III: ANS-Gn, r = 0.65, P = 0.043) compared with two-dimensional photogrammetry. However, two-dimensional photogrammetry revealed higher correlation between lower lip length and cephalometrically assessed angular hard tissue changes (Class II: SNB, r = 0.98, P = 0.007; N-B, r = 0.89, P = 0.037; N-Pg, r = 0.90, P = 0.033; Class III: SNB, r = - 0.54, P = 0.060; NAPg, r = - 0.65, P = 0.041; N-Pg, r = 0.58, P = 0.039).

Conclusions

Our findings suggest that cephalometry and two-dimensional photogrammetry offer the possibility to complement one another.

An approach to estimate body dimensions through constant body ratio benchmarks

Building a new anthropometric database is a difficult and costly job that requires considerable manpower and time. However, most designers and engineers do not know how to convert old anthropometric data into applicable new data with minimal errors and costs (Wang et al., 1999). To simplify the process of converting old anthropometric data into useful new data, this study analyzed the available data in paired body dimensions in an attempt to determine constant body ratio (CBR) benchmarks that are independent of gender and age. In total, 483 CBR benchmarks were identified and verified from 35,245 ratios analyzed. Additionally, 197 estimation formulae, taking as inputs 19 easily measured body dimensions, were built using 483 CBR benchmarks. Based on the results for 30 recruited participants, this study determined that the described approach is more accurate and cost-effective than alternative techniques.

Age- and sex-related changes in the normal human external nose

The objective of this study was to measure: (1) normal sex-related dimensions of external nose (linear distances, ratios, angles, volume and surface area); and (2) growth changes between childhood and old age. The three-dimensional coordinates of several soft-tissue landmarks on the external nose were obtained by a non-invasive, computerized digitizer in 519 male and 340 female healthy subjects aged 4-73 years. The subjects were divided into 11 non-overlapping age groups: for children and preadolescent subjects, 2-year spans were used, while larger intervals were used for adolescent and adult subjects. From the landmarks, nasal volume and external surface area; nasal and alar base widths, nasal height, nasal bridge length, philtrum length, nasal tip protrusion, right and left nostril lengths, superior and inferior nostril widths; nasal tip protrusion-to-nasal height, and nasal width-to-nasal height ratios; nasal convexity, alar slope, and nasal tip angles were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. On average, men had larger nasal external volume and area, linear distances and nasal width-to-height ratio than women (p<0.01); no sex differences were found for the angles and the nasal tip protrusion-to-nasal height ratio. Age significantly influenced all analyzed measurements (p<0.001): nasal volume, area, linear distances increased from childhood to old age, while the nasal tip angle decreased as a function of age. No consistent age related patterns were found for the ratios and the nasal convexity and alar slope angles. Men and women had different age related patterns, with significant sex by age interactions (p<0.001). Overall, in most occasions male increments in nasal dimensions were larger than female ones. Data collected in the present investigation could serve as a database for the quantitative description of human nasal morphology during normal growth, development and aging. Forensic applications (evaluations of traumas, craniofacial alterations, teratogenic-induced conditions, facial reconstruction, aging of living and dead persons, personal identification) may also benefit from age and sex based data banks.

3D digital stereophotogrammetry: a practical guide to facial image acquisition

The use of 3D surface imaging technology is becoming increasingly common in craniofacial clinics and research centers. Due to fast capture speeds and ease of use, 3D digital stereophotogrammetry is quickly becoming the preferred facial surface imaging modality. These systems can serve as an unparalleled tool for craniofacial surgeons, proving an objective digital archive of the patient's face without exposure to radiation. Acquiring consistent high-quality 3D facial captures requires planning and knowledge of the limitations of these devices. Currently, there are few resources available to help new users of this technology with the challenges they will inevitably confront. To address this deficit, this report will highlight a number of common issues that can interfere with the 3D capture process and offer practical solutions to optimize image quality.

Three-dimensional evaluation of soft tissue changes after mandibular setback surgery in class III malocclusion patients according to extent of mandibular setback, vertical skeletal pattern, and genioplasty

OBJECTIVE

To investigate the 3-dimensional (3D) changes in the soft tissue after mandibular setback surgery (MSS).

STUDY DESIGN

Thirty-three skeletal class III malocclusion (SCIII) patients treated with MSS (bilateral sagittal split ramus osteotomy) were subdivided according to extent of MSS, vertical skeletal pattern (VP), and vertical-reduction genioplasty. Lateral cephalograms and 3D facial scan images were taken before and 6 months after surgery. Linear and angular variables were measured with Rapidform 2006 (Inus Technology).

RESULTS

After MSS, there were significant increases in the upper lip length and decreases in the lower lip length in the large setback, hypodivergent, and genioplasty groups. The mentolabial fold deepened less in the genioplasty group than in other groups. Although there was no skeletal advancement of the maxilla, the soft tissue convexity in the paranasal area increased more in the hyperdivergent group than in the hypodivergent group after MSS.

CONCLUSION

The extent of MSS, VP, and genioplasty could be used as guidelines for 1- and 2-jaw surgeries in SCIII borderline cases.

Accuracy and reproducibility of a 3-dimensional stereophotogrammetric imaging system

PURPOSE

To test the accuracy and reproducibility of a 3-dimensional (3D) stereophotogrammetric imaging system for measuring the facial soft tissues of healthy subjects.

MATERIALS AND METHODS

Three-dimensional soft tissue facial landmarks were obtained from the faces of 10 adult subjects, by use of a 3D stereophotogrammetric imaging system (Vectra; Canfield Scientific, Fairfield, NJ). Sixteen linear measurements were computed. Systematic and random errors between operators, calibration steps, and acquisitions were calculated.

RESULTS

No systematic errors were found for all performed tests (P > .05, paired t test). The method was repeatable, and random errors were always lower than 1 mm, except for the distance from cheilion to cheilion. Repeated sets of acquisition showed random errors up to 0.91 mm, without systematic biases.

CONCLUSION

The 3D stereophotogrammetric imaging system can assess the coordinates of facial landmarks with good precision and reproducibility. The method is fast and can obtain facial measurements with few errors.

Soft tissue facial morphometry in subjects with Moebius syndrome

Moebius syndrome is a congenital facial palsy associated with the impairment of ocular abduction. The three-dimensional characteristics of the facial soft tissues of 12 male and 14 female subjects [3-52 yr of age (mean age + standard deviation: 17 + 14 yr)] were measured using a non-invasive, computerized system; facial volumes, areas, angles, and distances were computed and compared with those obtained in reference subjects of the same age and gender. When compared with reference subjects, patients with Moebius syndrome had a more prominent and hyperdivergent face in the sagittal plane, a smaller and more prominent upper facial third; a smaller middle facial width; a smaller nose; smaller mandibular volume, depth, corpus length, and ramus height; and a more posterior positioned mandible, with a less prominent chin. In conclusion, patients with Moebius syndrome had a tendency towards a skeletal Class II pattern. These morphological variations may be the combined effect of a general alteration of the motor and sensitive facial nerves, including the trigeminal nerve, and of a maldevelopment of the brainstem.