Multi-modality 3D mandibular resection planning in head and neck cancer using CT and MRI data fusion: A clinical series.

OBJECTIVES: 3D virtual surgical planning (VSP) and guided surgery has been proven to be an effective tool for resection and reconstruction of the mandible. Currently, most widely used 3D VSP approaches to mandibular resection do not include detailed tumour information in the VSP. This manuscript presents a strategy where the aim was to incorporate tumour visualisation into the 3D virtual plan. Three-dimensional VSP of the mandibular resections was based on the fusion of CT and MRI data which was subsequently applied in clinical practice. METHODS: All patients diagnosed with oral squamous cell carcinoma between 2014 and 2017 at the University Medical Centre Groningen were included. The tumour was delineated on the MRI data, after which this dataset was fused with the CT bone data in order to construct a 3D bone and tumour model for virtual resection planning. Guided resections were performed and post-operative evaluation quantified the accuracy of the resection. The histopathological findings and patient and tumour characteristics were compared to those of a historical cohort (2009-2014) of conventional mandibular continuity resections. RESULTS: Twenty-four patients were included in the cohort. The average deviation from planned resection was found to be 2.2 mm. Histopathologic analysis confirmed all resection planes (bone) were tumour free, compared to 96.4% in the historic cohort. CONCLUSION: MRI-CT base tumour visualisation and 3D resection planning is a safe and accurate method for oncologic resection of the mandible. It is an improvement on the current methods reported for 3D resection planning based solely on CT data.

Phenylalanine tolerance can already reliably be assessed at the age of 2 years in patients with PKU.

BACKGROUND: The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe tolerance at early age to predict Phe tolerance at later age. AIM: This study was conducted to investigate the course of the individual Phe tolerance and to assess the predictive value of both the pre-treatment Phe concentration and Phe tolerance at 1 and 6 months and 1, 2, 3 and 5 years for Phe tolerance at 10 years of age. METHOD: Data on blood Phe concentration, prescribed Phe intake and weight of 213 early and continuously treated Dutch PKU patients up to 10 years of age were collected. Data acquired under good metabolic control were used in the study. Tolerance was expressed in mg/day and mg/kg per day. RESULTS: Data at 1 and 6 months and at 1, 2, 3 and 5 years of 61, 58, 59, 57, 56 and 59 patients were included for comparison with the Phe tolerance at 10 years. Phe tolerances (mg/kg per day) at 2, 3 and 5 years showed a clear correlation with the tolerance at 10 years of age (r = 0.608, r = 0.725 and r = 0.661). Results for tolerance expressed as mg/day were comparable. Pre-treatment Phe concentrations did not correlate significantly with the tolerance. CONCLUSION: Pre-treatment Phe is unreliable but Phe tolerance is a reliable predictor of the tolerance at 10 years of age, starting at 2 years of age.