An open-source, three-dimensional growth model of the mandible.

The available reference data for the mandible and mandibular growth consists primarily of two-dimensional linear or angular measurements. The aim of this study was to create the first open-source, three-dimensional statistical shape model of the mandible that spans the complete growth period. Computed tomography scans of 678 mandibles from children and young adults between 0 and 22 years old were included in the model. The mandibles were segmented using a semi-automatic or automatic (artificial intelligence-based) segmentation method. Point correspondence among the samples was achieved by rigid registration, followed by non-rigid registration of a symmetrical template onto each sample. The registration process was validated with adequate results. Principal component analysis was used to gain insight in the variation within the dataset and to investigate age-related changes and sexual dimorphism. The presented growth model is accessible globally and free-of-charge for scientists, physicians and forensic investigators for any kind of purpose deemed suitable. The versatility of the model opens up new possibilities in the fields of oral and maxillofacial surgery, forensic sciences or biological anthropology. In clinical settings, the model may aid diagnostic decision-making, treatment planning and treatment evaluation.

Acute toxicity after a diverting stoma and spacer prior to chemoradiation in locally advanced rectal cancer.

BACKGROUND AND PURPOSE: Chemoradiotherapy (CRT) followed by surgery is the standard of care for locally advanced rectal cancer (LARC). For grade ⩾3 acute diarrhea there is a relationship between dose and irradiated small bowel volume. The aim of this study was to evaluate whether combined placement of a diverting stoma and sigmoid spacer (DSSS) led to reduced irradiated small bowel volume and less grade ⩾3 acute diarrhea in the treatment of LARC. MATERIALS/METHODS: Between 2003 and 2010, 54 of 189 LARC patients treated with CRT in two institutions had a DSSS prior to CRT. Data on patient and treatment characteristics and outcomes were collected retrospectively. Delineation of small bowel was performed with planning CT-scans. CTCAE version 4.0 was used for acute toxicity. RESULTS: Patients with a DSSS had significantly less small bowel volume irradiated up to doses of 20Gy. This difference was not observed for the higher dose levels. CRT induced grade ⩾3 acute diarrhea was not different between the two groups (8.3% vs. 12.8%; p=0.41). CONCLUSION: DSSS is not clearly beneficial to reduce grade ⩾3 acute diarrhea, and it must be considered whether placement of a DSSS is justified for this purpose.