Development and reproducibility of a 3D stereophotogrammetric reference frame for facial soft tissue growth of babies and young children with and without orofacial clefts.

The aim of this study was to develop a reference frame for three dimensional (3D) facial soft tissue growth analysis in children and to determine its reproducibility. Two observers twice placed the reference frame on 39 3D-stereophotogrammetry facial images of children with orofacial clefts and control children. The observers' performances were analyzed by calculating mean distance, distance variability, and P95 between the same facial surfaces at two different time points. Correlations between observers were analyzed with Pearson's correlation coefficient. The influence of presence of a cleft, absence of one ear in the photograph, and age on the reproducibility of the reference frame was checked using Student's t test. Results of intraobserver comparisons showed a mean distance of <0.40 mm, distance variability of <0.51 mm, and P95 of <0.80 mm. For interobserver reliability, the mean distance was <0.52 mm, distance variability was <0.53 mm, and P95 was <1.10 mm. Presence of a cleft, age, and absence of one ear on the 3D photograph did not have a significant influence on the reproducibility of placing the reference frame. The children's reference frame is a reproducible method to superimpose on 3D soft tissue stereophotogrammetry photographs of growing individuals with and without orofacial clefts.

One year postoperative hard and soft tissue volumetric changes after a BSSO mandibular advancement.

In this study, cone beam computed tomography (CBCT) and three dimensional (3D) stereophotogrammetry are used to compare the 3D skeletal and soft tissue changes caused by a bilateral sagittal split osteotomy (BSSO) 1 year after a mandibular advancement. Eighteen consecutive patients with a hypoplastic mandible were treated with a BSSO according to the Hunsuck modification. Preoperatively and 1 year postoperatively, a CBCT scan was acquired and a 3D photograph. The pre- and postoperative CBCT scans were matched using voxel based registration. After registration, the mandible could be segmented in the pre- and postoperative scans. The preoperative scan was subtracted from the postoperative scan, resulting in the hard tissue difference. To investigate the soft tissue changes, the pre- and postoperative 3D photographs were registered using surface based registration. After registration the preoperative surface could be subtracted from the postoperative surface, resulting in the overall volumetric difference. As expected, a correlation between mandibular advancent and volumetric changes of the hard tissues was found. The correlation between advancement and soft tissues was weak. The labial mental fold stretched after surgery. This study proved that using 3D imaging techniques it is possible to document volumetric surgical changes accurately and objectively.

Variation of the face in rest using 3D stereophotogrammetry.

To evaluate treatment outcomes following oral and maxillofacial surgery, pre- and post-treatment three-dimensional (3D) photographs of the patient's face can assessed, but this procedure is accurate only if the face is captured with the same facial expression every time. The purpose of this prospective study was to determine variations in the face at rest; 100 3D photographs of the same individual were acquired at different times. Initially, 50 3D photographs were obtained; 25 using a wax bite to ensure similar occlusion between subsequent photographs and 25 without wax bite. This procedure was repeated 6 weeks later. Variation of the face at rest was computed. The influence of time and wax bite was investigated. Different anatomical regions were investigated separately. A mean variation of 0.25 mm (0.21-0.27 mm) was found (standard deviation 0.157 mm). No large differences were found between different time points or use of wax bite. Regarding separate anatomical regions, there were small variations in the nose and forehead regions; the largest variations were found in the mouth and eyes. This study showed small overall variation within the face at rest. In conclusion, different 3D photographs can be reproduced accurately and used in a clinical setting for treatment follow-up and evaluation.

3D Stereophotogrammetric assessment of pre- and postoperative volumetric changes in the cleft lip and palate nose.

In cleft lip and palate patients the shape of the nose invariably changes in three dimensions (3D) due to rhinoplastic surgery. The purpose of this study was to evaluate stereophotogrammetry as a 3D method to document volumetric changes of the nose in patients with a cleft lip (CL) or cleft lip and palate (CLP) after secondary open rhinoplasty. 12 patients with unilateral CL or CLP were enrolled in the study prospectively. 3D facial images were acquired using 3D stereophotogrammetry preoperatively and 3 months postoperatively. A 3D cephalometric analysis of the nose was performed and volumetric data were acquired. The reliability of the method was tested by performing an intra- and inter-observer analysis. Left, right and total nasal volumes and symmetry were compared. No statistically significant differences (p<0.05) were found within and between observers for the measured volumes and symmetry. Postoperatively, the total volume of the nose increased significantly, especially the volume at the cleft side. No significant volume difference pre- and postoperatively was found for the non-cleft side. The symmetry of the nose improved significantly. 3D stereophotogrammetry is a sensitive, quick, non-invasive method for evaluating volumetric changes of the nose in patients with cleft lip or cleft lip and palate.

3D evaluation of the lingual fracture line after a bilateral sagittal split osteotomy of the mandible.

The purpose of this prospective observational study was to evaluate whether cone beam CT (CBCT) is a useful tool for analyzing the fracture line in a bilateral sagittal split osteotomy (BSSO). The patient group consisted of 40 consecutive patients (9 males and 31 females) with a mandibular hypoplasia who underwent a BSSO advancement (Hunsuck modification; n=80 splits) between September 2006 and July 2008. The mean age at the time of surgery was 34 years (range 17-61 years). A newly developed lingual split scale was used to categorize the path of the fracture line on the lingual side of the ramus based on one-day postoperative data sets reconstructed from CBCT data. Although all splits (n=80) were performed according to the standardized protocol, only 51% of the fracture lines run according to the Hunsuck's description, whereas 33% ran through the mandibular canal and 16% split otherwise. The split pattern was influenced by the length of the medial osteotomy (p=0.01). In conclusion, 3D imaging is a useful tool for analyzing the surgical outcome of a BSSO and has the potential to provide substantial data on the position of the proximal segments as a result of the lingual fracture line.

Evaluation of reproducibility and reliability of 3D soft tissue analysis using 3D stereophotogrammetry.

In 3D photographs the bony structures are neither available nor palpable, therefore, the bone-related landmarks, such as the soft tissue gonion, need to be redefined. The purpose of this study was to determine the reproducibility and reliability of 49 soft tissue landmarks, including newly defined 3D bone-related soft tissue landmarks with the use of 3D stereophotogrammetric images. Two observers carried out soft-tissue analysis on 3D photographs twice for 20 patients. A reference frame and 49 landmarks were identified on each 3D photograph. Paired Student's t-test was used to test the reproducibility and Pearson's correlation coefficient to determine the reliability of the landmark identification. Intra- and interobserver reproducibility of the landmarks were high. The study showed a high reliability coefficient for intraobserver (0.97 (0.90 - 0.99)) and interobserver reliability (0.94 (0.69 - 0.99)). Identification of the landmarks in the midline was more precise than identification of the paired landmarks. In conclusion, the redefinition of bone-related soft tissue 3D landmarks in combination with the 3D photograph reference system resulted in an accurate and reliable 3D photograph based soft tissue analysis. This shows that hard tissue data are not needed to perform accurate soft tissue analysis.

Body dysmorphic disorder screening in maxillofacial outpatients presenting for orthognathic surgery.

Body dysmorphic disorder (BDD) is a severe psychiatric disease with delusions about defects in appearance for which patients seek surgical help. This is the first European study to determine the half-year prevalence of BDD in a maxillofacial outpatient clinic. A total of 160 patients with maxillofacial problems completed a validated self-report questionnaire, while a staff member scored maxillofacial defects on a severity scale. Twenty-eight (17%) patients had excessive concerns about their appearance, which negatively influenced their psychosocial functioning; 16 patients (10%; 95%CI 5-15%) screened positive for BDD. The high prevalence of problems related to psychosocial functioning and the occurrence of BDD in maxillofacial patients means that maxillofacial surgeons should take psychological concerns about physical defects into account.

The accuracy of matching three-dimensional photographs with skin surfaces derived from cone-beam computed tomography.

The state-of-the-art diagnostic tools in oral and maxillofacial surgery and preoperative orthodontic treatment are mainly two-dimensional, and consequently reveal limitations in describing the three-dimensional (3D) structures of a patient's face. New 3D imaging techniques, such as 3D stereophotogrammetry (3D photograph) and cone-beam computed tomography (CBCT), have been introduced. Image fusion, i.e. registration of a 3D photograph upon a CBCT, results in an accurate and photorealistic digital 3D data set of a patient's face. The purpose of this study was to determine the accuracy of three different matching procedures. For 15 individuals the textured skin surface (3D photograph) and untextured skin surface (CBCT) were matched by two observers using three different methods to determine the accuracy of registration. The registration error was computed as the difference (mm) between all points of both surfaces. The registration errors were relatively large at the lateral neck, mouth and around the eyes. After exclusion of artefact regions from the matching process, 90% of the error was within+/-1.5 mm. The remaining error was probably caused by differences in head positioning, different facial expressions and artefacts during image acquisition. In conclusion, the 3D data set provides an accurate and photorealistic digital 3D representation of a patient's face.

Long-term prognosis of primary retroperitoneal soft tissue sarcoma.

AIMS: To evaluate the result of treatment and long-term outcome of a population-based cohort of patients with retroperitoneal soft tissue sarcoma (RSTS). METHODS: Between 1 January 1989 and 1 January 1994, 143 patients diagnosed as having primary RSTS were selected from a national pathology database (PALGA) in the Netherlands. In this population-based group of patients, the result of surgery, overall survival (OS) and disease-free survival (DFS) were analysed as well as factors affecting OS and DFS. Median follow-up was 10.2 years. RESULTS: Operative treatment resulted in a complete tumour resection in 55% of the patients (n=78), low- and intermediate-grade tumours were more often completely resected than high-grade tumours (P=0.016). Five- and 10-year cumulative OS was 39% and 21%, respectively, while DFS was 22% and 17%, respectively. In a multivariate analysis low malignancy grade (P=0.017) and a complete tumour resection (P<0.001) were associated with better OS. CONCLUSIONS: Complete tumour resection and low malignancy grade were independent favourable prognosticators. However, these factors were related too, since surgical success was influenced by malignancy grade.