Presentation and short-term evaluation of an all-in-one patient-specific implant for cranial reconstruction: A randomized controlled trial.

Cranial reconstruction after bone graft harvesting remains a challenge. A patient-specific implant (PSI) to guide harvesting and reconstruction was evaluated and compared with the use of a free-hand procedure with calcium phosphate cement (C). Patients were randomized to either the PSI or C group. The outcome was measured clinically and radiographically as the primary endpoint. Secondary endpoints were ease of application, patient and surgeon satisfaction, and the complication rate. Twenty patients were randomized to the PSI (n=10) and C (n=10) groups. Two PSI patients were switched to the cement group due to a poor fit of the PSI. There was a non-significant trend towards more successful outcomes in the PSI group. Two PSI patients presented palpable screws, and one cement patient had a palpable dimple. Cone beam computed tomography showed a significantly lower median volume discrepancy in the PSI group (P<0.0001). The total surgical manipulation time was significantly higher in the PSI group. At 10 days postoperative, three PSI and two C patients presented with minor postoperative complications. There was no significant difference in patient or surgeon satisfaction. PSIs are a reliable alternative to cement. This PSI is novel as it also serves as a guide for harvesting the bone blocks required for reconstructive purposes.

Long-term quality of life outcomes of maxillomandibular advancement osteotomy in patients with obstructive sleep apnoea syndrome.

This study was performed to evaluate the long-term impact of maxillomandibular advancement (MMA) surgery on the apnoea-hypopnoea index (AHI) and quality of life (QoL) in patients with obstructive sleep apnoea syndrome (OSAS). The medical files of 12 OSAS patients who underwent MMA by one surgeon between 1995 and 1999 were reviewed retrospectively. Patients received a clinical assessment, polysomnography, and QoL questionnaires as part of routine care preoperatively (n=12), within 2 years postoperative (n=12), and again in 2016 (n=9). A successful surgical outcome was defined as an AHI decrease of >50% with <20 events/h. Of the 66.7% (8/12) of patients who were initially cured, 66.7% (4/6) remained stable at a median follow-up of 19 years. Only the two patients with the highest AHI showed abnormal Epworth Sleepiness Scale scores. After convalescence, most patients reported stable symptomatic improvement. Aesthetic changes were found acceptable and all but one patient stated that they would undergo the surgery again. It is concluded that MMA is a safe and effective procedure. Ageing and weight gain might counterbalance the positive effects of surgery in the long term. It is therefore suggested that re-evaluation every 5 years should be scheduled, since a spontaneous AHI increase over time does not seem to be reflected by symptomatic changes.

Three-dimensional volumetric changes in the upper airway after maxillomandibular advancement in obstructive sleep apnoea patients and the impact on quality of life.

Obstructive sleep apnoea (OSA) is a sleep-related breathing disorder, characterized by repetitive airway obstructions, causing disruptive snoring and daytime sleepiness. Maxillomandibular advancement (MMA), which enlarges the upper airway, is a therapeutic surgical approach. However, no study has performed an upper airway sub-region analysis using validated three-dimensional (3D) anatomical and technical limits on cone beam computed tomography (CBCT). Hence, this prospective, observational trial was performed to evaluate 3D volumetric changes in the upper airway according to validated 3D cephalometric landmarks, before and after MMA, for all patients with a polysomnography diagnosis of OSA (apnoea-hypopnoea index (AHI) ≥5). The secondary objective was to evaluate the impact of MMA on the AHI and in a subjective manner with the Epworth Sleepiness Scale (ESS) and OSA questionnaire. Eleven consecutive OSA patients were included. A significant volume increase in the oropharynx (P=0.002) and hypopharynx (P=0.02) was observed, in contrast to a non-significant volume reduction in the nasopharynx (P >0.05). The median AHI (P=0.03) and ESS score (P=0.004) decreased significantly as a result of surgery. In conclusion, MMA significantly enlarges the airway volume of the oropharynx and hypopharynx and is associated with improved quality of life.

A cone-beam CT based technique to augment the 3D virtual skull model with a detailed dental surface.

Cone-beam computed tomography (CBCT) is used for maxillofacial imaging. 3D virtual planning of orthognathic and facial orthomorphic surgery requires detailed visualisation of the interocclusal relationship. This study aimed to introduce and evaluate the use of a double CBCT scan procedure with a modified wax bite wafer to augment the 3D virtual skull model with a detailed dental surface. The impressions of the dental arches and the wax bite wafer were scanned for ten patient separately using a high resolution standardized CBCT scanning protocol. Surface-based rigid registration using ICP (iterative closest points) was used to fit the virtual models on the wax bite wafer. Automatic rigid point-based registration of the wax bite wafer on the patient scan was performed to implement the digital virtual dental arches into the patient's skull model. Probability error histograms showed errors of < or =0.22 mm (25% percentile), < or =0.44 mm (50% percentile) and < or =1.09 mm (90% percentile) for ICP surface matching. The mean registration error for automatic point-based rigid registration was 0.18+/-0.10 mm (range 0.13-0.26 mm). The results show the potential for a double CBCT scan procedure with a modified wax bite wafer to set-up a 3D virtual augmented model of the skull with detailed dental surface.