New method for analysing spatial relationships of facial muscles on MRI: a pilot study.

Dysfunction of the facial musculature can have significant physical, social, and psychological consequences. In surgeries such as cleft surgery or craniofacial bimaxillary osteotomies, the perioral facial muscles may be detached or severed, potentially altering their functional vectors and mimicry capabilities. Ensuring correct reconstruction and maintenance of anatomical sites and muscle vectors is crucial in these procedures. However, a standardized method for perioperative assessment of the facial musculature and function is currently lacking. The aim of this study was to develop a workflow to analyse the three-dimensional vectors of the facial musculature using magnetic resonance imaging (MRI) scans. A protocol for localizing the origins and insertions of these muscles was established. The protocol was implemented using the 3DMedX computer program and tested on 7 Tesla MRI scans obtained from 10 healthy volunteers. Inter- and intra-observer variability were assessed to validate the protocol. The absolute intra-observer variability was 2.6 mm (standard deviation 2.0 mm), and absolute inter-observer variability was 2.6 mm (standard deviation 1.5 mm). This study presents a reliable and reproducible method for analysing the spatial relationships and functional significance of the facial muscles. The workflow developed facilitates perioperative assessment of the facial musculature, potentially aiding clinicians in surgical planning and potentially enhancing the outcomes of midface surgery.

The average three-dimensional face for different sex and age groups in a Dutch population.

The increasing use of three-dimensional imaging calls for reference models representing large parts of the population. The aim of this prospective study was to create templates depicting facial maturation in the younger age groups. Healthy Dutch volunteers were captured, without selection of inclusions. Three-dimensional average faces were created using MATLAB, for both genders in four age groups (4-8 years, 8-12 years, 12-16 years, and ≥16 years). Variation within the groups was calculated and depicted on an average face with a green to red colour scale, corresponding to standard deviations between 0 and ≥ 3 mm, respectively. Measurements of the distances of eight peri-oral landmarks were provided as ratios. The statistical analysis was performed using ANOVA and Tukey's test. Three-dimensional reconstructions of the average face and their first principal component were created for each gender and age group. The first principal component comprised the facial width for each group, and the variation of landmarks was low. All ratios showed an increasing trend with increasing age, except for the ratio of philtrum width to mouth width. This study is novel in comparing facial morphology by means of ratios and in creating average faces for the different young age groups. These data provide useful insights into facial maturation, which might be beneficial for facial surgeons.

Stereolithographic skull models in the surgical planning of fronto-supraorbital bar advancement for non-syndromic trigonocephaly.

BACKGROUND: Fronto-supraorbital bar advancement in the treatment for trigonocephaly is associated with extensive intraoperative blood loss and compensatory erythrocyte transfusions. Since both are related to the length of surgery, efforts have been focused on optimizing preoperative preparations. The utilization of three-dimensional skull models in surgical planning allows for familiarization with the patient's anatomy, the optimization of osteotomies, the preparation of bone grafts and the selection of fixation plates. METHODS: Stereolithographic skull models were used in the surgical planning for five patients with non-syndromic trigonocephaly treated in Wilhelmina Children's Hospital in 2012. A comparison group was composed of six patients with non-syndromic trigonocephaly treated by the same surgical team. Once all patients had received surgery, a retrospective chart review was performed to identify the volumes of perioperative blood loss and erythrocyte transfusions and the length of the procedure. Furthermore, the educational value of the models was assessed in a round table discussion with the surgical team and residents. RESULTS: In the model group patients were transfused a mean 24 ml/kg (27% of Estimated Blood Volume [EBV]) compared to 16 ml/kg (18% of EBV) in the comparison group (P = 0.359) for a mean perioperative blood loss of 53 ml/kg (60% of EBV) in the model group against 40 ml/kg (41% of EBV) in the comparison group (P = 0.792). The mean length of surgery in the model groups was 256 min versus 252 min in the comparison group (P = 0.995). Evaluation of educational purposes demonstrated that the models had a role in the instruction of residents and communication to parents, but did not improve the insight of experienced surgeons. CONCLUSION: The usage of stereolithographic skull models in the treatment of non-syndromic trigonocephaly does not reduce the mean volume of perioperative erythrocyte transfusions, the mean volume of perioperative blood loss nor the mean length of the surgical procedure. Nonetheless, the models do facilitate the education of the patient's parents as well as support the training of residents.

The influence of a Le Fort I impaction and advancement osteotomy on smile using a modified alar cinch suture and V-Y closure: a prospective study.

A previous report from the authors' department showed that a modified alar cinch suture combined with a muco-musculo-periosteal V-Y closure (mACVY) improves nasolabial mobility. To test if the improvements were equal to the range of nasolabial mobility in non-dysgnathic persons, a prospective study was carried out in 56 patients: 31 with mACVY, 25 with simple closing sutures (SCS) and 18 non-operated, angle class I volunteers. Standardized full facial frontal photographs, taken immediately preoperatively and 18 months postoperatively were used. The landmarks, alare, crista philtri and cheilion were analysed. The test has a standard deviation of 0.9 mm. Intra-group changes, paired t-test, and inter-group differences, unpaired t-test (p<0.05) were statistically analysed. The results show significant preoperative differences in nasolabial mobility compared with the control group, for both groups. Postoperative mobility improved in both groups, but significantly with mACVY with horizontal movement of cheilion and alare, and the vertical movement of crista philtri and less so for the vertical movement of crista philtri with SCS. Postoperative inter-group differences in mobility were small and significant for SCS vs the control group. It can be concluded that using mACVY improves orofacial movement to the level of normal class I volunteers.

The effect of alar cinch sutures and V-Y closure on soft tissue dynamics after Le Fort I intrusion osteotomies.

UNLABELLED: Adverse effects on the soft tissues after Le Fort I osteotomies include: broadening of the alar base, loss of vermilion show of the upper lip and down sloping of the commissures. In theory, an alar cinch suture combined with a muco-musculo-periosteal V-Y closure (ACVY) should improve not only the nasal width, but would also improve the dynamics of some of the mimic muscles. To test the validity of this hypothesis, a prospective study was set up including 22 patients, using standardized full facial frontal photographs, taken immediately preoperatively and 18 months postoperatively. Sets containing three pictures were made: soft tissue in repose, maximum closed mouth smile and maximum smile. The landmarks, alare, crista philtri and cheilion were analysed. The preliminary results show that ACVY-closure does significantly improve the horizontal movement of cheilion with both maximum closed mouth smile and maximum smile, as well as the vertical movement of crista philtri with maximum closed mouth smile. CONCLUSION: The Le Fort I osteotomy with ACVY improves the orofacial dynamics.

The reliability of frontal facial photographs to assess changes in nasolabial soft tissues.

A simple, modified method to evaluate changes in the nasolabial soft tissues after orthognathic surgery is presented. Eighteen healthy volunteers were photographed in a standardized manner with a 2-month interval. Pictures were taken with the soft tissues in repose and 'maximum closed mouth smile'. Discrepancies for repose and dynamic excursions (x and y coordinates) were calculated for the landmarks alare, crista philtri and cheilion. Multiple analysis of variance revealed no significant interaction for intra-observer variance and time of recording. Coefficients of reliability (repose: 90-99%, dynamic excursion (cheilion): >95%), Spearman correlation coefficients (repose: >0.8, dynamic: >0.6) and squared correlation (repose: >75%, dynamic: >50%) showed this method to be reliable for repose and dynamic excursions. The error of measurement was less than 1.8 mm for both repose and dynamic excursions (SD(differences)=0.9 mm). This is smaller than mean differences in nasolabial soft-tissues excursions found between the pre- and post-Le Fort I osteotomy situation in a previous study using video imaging. The discrepancies found were in keeping with other earlier reports for 2D and 3D measuring methods. The method as proposed is simple, cost effective and can be used to evaluate soft-tissue changes after orthognathic surgery.