A survey of the UK maxillofacial laboratory service: Profiles of staff and work

IMproving facial PRosthesis construction with contactlESs Scanning and Digital workflow (IMPRESSeD): study protocol for a feasibility crossover randomised controlled trial of digital versus conventional manufacture of facial prostheses in patients with orbital or nasal facial defects

BACKGROUND

Facial prostheses can have a profound impact on patients' appearance, function and quality of life. There has been increasing interest in the digital manufacturing of facial prostheses which may offer many benefits to patients and healthcare services compared with conventional manufacturing processes. Most facial prosthesis research has adopted observational study designs with very few randomised controlled trials (RCTs) documented. There is a clear need for a well-designed RCT to compare the clinical and cost-effectiveness of digitally manufactured facial prostheses versus conventionally manufactured facial prostheses. This study protocol describes the planned conduct of a feasibility RCT which aims to address this knowledge gap and determine whether it is feasible to conduct a future definitive RCT.

METHODS

The IMPRESSeD study is a multi-centre, 2-arm, crossover, feasibility RCT with early health technology assessment and qualitative research. Up to 30 participants with acquired orbital or nasal defects will be recruited from the Maxillofacial Prosthetic Departments of participating NHS hospitals. All trial participants will receive 2 new facial prostheses manufactured using digital and conventional manufacturing methods. The order of receiving the facial prostheses will be allocated centrally using minimisation. The 2 prostheses will be made in tandem and marked with a colour label to mask the manufacturing method to the participants. Participants will be reviewed 4 weeks following the delivery of the first prosthesis and 4 weeks following the delivery of the second prosthesis. Primary feasibility outcomes include eligibility, recruitment, conversion, and attrition rates. Data will also be collected on patient preference, quality of life and resource use from the healthcare perspective. A qualitative sub-study will evaluate patients' perception, lived experience and preference of the different manufacturing methods.

DISCUSSION

There is uncertainty regarding the best method of manufacturing facial prostheses in terms of clinical effectiveness, cost-effectiveness and patient acceptability. There is a need for a well-designed RCT to compare digital and conventional manufacturing of facial prostheses to better inform clinical practice. The feasibility study will evaluate key parameters needed to design a definitive trial and will incorporate early health technology assessment and a qualitative sub-study to identify the potential benefits of further research.

TRIAL REGISTRATION

ISRCTN ISRCTN10516986). Prospectively registered on 08 June 2021,  https://www.isrctn.com/ISRCTN10516986 .

An in-vitro study to assess the feasibility, validity and precision of capturing oncology facial defects with multimodal image fusion

AIM

Assess the feasibility, validity and precision of multimodal image fusion to capture oncology facial defects based on plaster casts.

METHODS

Ten casts of oncology facial defects were acquired. To create gold standard models, a 3D volumetric scan of each cast was obtained with a cone beam computed tomography (CBCT) scanner (NewTomVG). This was converted into surface data using open-source medical segmentation software and cropped to produce a CBCT mask using an open-source system for editing meshes. For the experimental model, the external facial features were captured using stereophotogrammetry (DI4D) and the defect was recorded with a custom optical structured light scanner. The two meshes were aligned, merged and resurfaced using MeshLab to produce a fused model. Analysis was performed in MeshLab on the best fit of the fused model to the CBCT mask. The unsigned mean distance was used to measure the absolute deviation of each model from the CBCT mask. To assess the precision of the technique, the process of producing the fused model was repeated to create five models each for the casts representing the best, middle and worst results.

RESULTS

Global mean deviation was 0.22 mm (standard deviation 0.05 mm). The precision of the method appeared to be acceptable although there was variability in the location of the error for the worst cast.

CONCLUSION

This method for merging two independent scans to produce a fused model shows strong potential as an accurate and repeatable method of capturing facial defects. Further research is required to explore its clinical use.

Maxillofacial prostheses challenges in resource constrained regions

BACKGROUND

This study reviewed the current state of maxillofacial rehabilitation in resource-limited nations.

METHOD

A rigorous literature review was undertaken using several technical and clinical databases using a variety of key words pertinent to maxillofacial prosthetic rehabilitation and resource-limited areas. In addition, interviews were conducted with researchers, clinicians and prosthetists that had direct experience of volunteering or working in resource-limited countries.

RESULTS

Results from the review and interviews suggest rehabilitating patients in resource-limited countries remains challenging and efforts to improve the situation requires a multifactorial approach.

CONCLUSIONS

In conclusion, public health awareness programmes to reduce the causation of injuries and bespoke maxillofacial prosthetics training programmes to suit these countries, as opposed to attempting to replicate Western training programmes. It is also possible that usage of locally sourced and cheaper materials and the use of low-cost technologies could greatly improve maxillofacial rehabilitation efforts in these localities. Implications for Rehabilitation More information and support needs to be provided to maxillofacial defect/injuries patients and to their families or guardians in a culturally sensitive manner by governments. The health needs, economic and psychological needs of the patients need to be taken into account during the rehabilitation process by clinicians and healthcare organizations. The possibility of developing training programs to suit these resource limited countries and not necessarily follow conventional fabrication methods must be looked into further by educational entities.

Maxillofacial prosthetic rehabilitation in the UK: a survey of maxillofacial prosthetists' and technologists' attitudes and opinions

Maxillofacial prostheses are constructed by maxillofacial prosthetists and technologists (MPTs), as an alternative treatment when maxillofacial defects cannot be surgically fulfilled. A questionnaire was conducted surveying 220 MPTs working in all UK maxillofacial units about their opinions, attitudes, and experience regarding several aspects related to maxillofacial silicone prostheses. Numbers and percentages of maxillofacial prostheses, their retention method, serviceability, reduced serviceability causes, and digital technologies (DT) used in constructing prostheses were analysed. Thousand hundred and ninety-three prostheses were constructed (42% ocular, 31% auricular, 13% orbital, 12% nasal, 1% composite, more than one facial prosthesis). Adhesives commonly retained orbital (48%) and nasal (45%) prostheses. Implant-retained bars commonly retained auricular prostheses (70%). Ocular prostheses were entirely retained by undercuts. Implant-retained prostheses remained serviceable for twice as long (19-24 months) as adhesive-retained prostheses (7-12 months). Causes for prosthesis replacement included colour changes (71%), poor maintenance (41%), and silicone tear (37%). Thirty-one percent of MPTs used DT computer software and programs for designing and constructing maxillofacial prostheses. In conclusion, adhesives, implant-retained bars and magnets are commonly used retentive methods. Prosthesis failure is caused mainly by colour change, poor maintenance, silicone tear and delamination. Different DTs are used by one-third of MPTs.