Evolution of design considerations in complex craniofacial reconstruction using patient-specific implants.

Previously published evidence has established major clinical benefits from using computer-aided design, computer-aided manufacturing, and additive manufacturing to produce patient-specific devices. These include cutting guides, drilling guides, positioning guides, and implants. However, custom devices produced using these methods are still not in routine use, particularly by the UK National Health Service. Oft-cited reasons for this slow uptake include the following: a higher up-front cost than conventionally fabricated devices, material-choice uncertainty, and a lack of long-term follow-up due to their relatively recent introduction. This article identifies a further gap in current knowledge - that of design rules, or key specification considerations for complex computer-aided design/computer-aided manufacturing/additive manufacturing devices. This research begins to address the gap by combining a detailed review of the literature with first-hand experience of interdisciplinary collaboration on five craniofacial patient case studies. In each patient case, bony lesions in the orbito-temporal region were segmented, excised, and reconstructed in the virtual environment. Three cases translated these digital plans into theatre via polymer surgical guides. Four cases utilised additive manufacturing to fabricate titanium implants. One implant was machined from polyether ether ketone. From the literature, articles with relevant abstracts were analysed to extract design considerations. In all, 19 frequently recurring design considerations were extracted from previous publications. Nine new design considerations were extracted from the case studies - on the basis of subjective clinical evaluation. These were synthesised to produce a design considerations framework to assist clinicians with prescribing and design engineers with modelling. Promising avenues for further research are proposed.

Postoperative radiographs after open reduction and internal fixation of mandibular fractures: clinical need or unnecessary radiation?

Postoperative radiographs are conventionally taken after open reduction and internal fixation (ORIF) of mandibular fractures, but routine radiographic exposure in patients who have no clinical signs may not be justified. To find out whether radiographs influence immediate postoperative management, and whether they can be used to predict long-term complications, we retrospectively reviewed the radiographs and case notes of 92 patients who had ORIF of isolated mandibular fractures between June 2010 and June 2012. We evaluated them for the adequacy of reduction and fixation using locally agreed criteria, and correlated them with immediate and long-term outcomes as recorded in the case notes. Eleven patients had complications, usually infection. All 4 patients who required repeat ORIF had worrying signs and symptoms despite the immediate postoperative radiograph looking favourable. The radiographs of 7 patients looked unfavourable, but no patient required another operation, and none developed complications. Routine postoperative radiographs after ORIF of mandibular fractures seem to have little value in the management of patients, as the decision to reoperate is based on clinical signs rather than radiographic appearance, and radiographic appearance is not associated with long-term outcomes. Our findings suggest that radiographs are valuable only in patients with clear clinical indications and, in view of the risk and cost of radiation, we question their continued use.

Le Fort I advancement osteotomies of 1 cm or more. How safe or stable?

We studied the results and stability of Le Fort I maxillary osteotomies with advancement of at least 1cm. We analysed prospective data from 32 consecutive patients who were operated on by a single surgeon between 1985 and 2007, and who had mean advancement of the maxilla of 14 mm (range 10-22 mm). Mean relapse for all cases antero-posteriorly was 1mm, 10% (range 0-4mm). Relapse was marginally greater in the 24 patients with a repaired cleft palate (11%) compared with those without a cleft (8%). The results were essentially stable at least one year after surgery and without significant complications. This study indicates that Le Fort I osteotomies of 1cm or more carried out in the way described are safe and stable.

Metastatic cutaneous head and neck renal cell carcinoma with no known primary: case report.

Renal cell carcinoma represents 2-3% of all adult malignancies, and metastasis to the head and neck is a presenting complaint in 8% of these patients. Cutaneous facial renal cell carcinoma with no known primary renal tumour is unusual. We report a case of renal cell carcinoma of the nose with no known primary.