This study aims to characterise biomechanical behaviour of complex mandibular reconstructions and to provide an accurate determination of the functional loadings of the mandible and its reconstructive element using finite element analysis (FEA). The ultimate goal of this work is to provide clinically relevant information to identify the best free flaps for planning of surgeries and improve postoperative performance.
Within Cheshire & Merseyside over 1,000 individuals a year are diagnosed with head and neck cancer, with some central city wards having 4 times the UK average. Oral cancer is frequently diagnosed at a locally advanced stage. Surgical management of these tumours commonly involves reconstruction to restore both facial form and vital functions of daily living following surgical resection of the mandible. The gold-standard for reconstruction of such defects is the use of free flaps of vascularized autologous bone sourced from one of a variety of suitable donor sites. Fibula free flap and radial forearm free flap are among the most commonly used to reconstruct the mandible, although iliac crest and scapular flaps can also be used for reconstruction of tooth-bearing segments and osteo-cutaneous reconstruction for mandibular and maxillary segments. In each case, the ambition is to restore both bony continuity of the lost tooth-bearing segments and facial form. However, the choice of the reconstructive element can impact the geometrical shape of the mandible after surgery, which can have an impact on its biomechanical behaviour (Cheng et al. 2022).
Extensive surgical reconstruction frequently alters both the mandibular form and its inherent strength. Changes in shape and muscular function/ability can result in weakening of the construct, and its capability to withstand forces such as those generated during chewing. This can cause the reconstructed element to be more fragile and result in fracture due to the accumulation of bone micro-damage from altered stress over time. The restorative dental rehabilitation of these patients with implants supported prostheses is key to improving function, aesthetics and quality of life; however, this can only be achieved with an intact reconstruction of the maxilla-mandibular functional unit.
Improvements in technology, computational modelling and 3D printing offers a novel approach to surgical planning and rehabilitation. Detailed, validated biomechanical models with accurate geometry and material properties are now possible, improving on past approaches. These can identify regions at risk of post-operative failure and facilitate improvement in patient-specific planning for complex defects.
Study Aims and Objectives
Currently, there is limited understanding of what contributes to force concentration, leading to mechanical (plate) or biological (healing osteotomy) failure. This may be due to design inaccuracies or unrecognised flaws in reconstruction (e.g., angles or position of osteotomy). Our main aim is to address: do different reconstructive elements and surgical techniques influence the function of the TMJ, the mechanical environment of the combined mandible and reconstructive element, and muscle loading during chewing?
Training and Project Structure
Training will be provided throughout the study in several ways. Project-specific hands-on training will be provided by the supervisory team as needed following regular Development Needs Analysis. This includes protocol training, lab inductions, health and safety training, seminars, and journal clubs. As a member of the Liverpool Doctoral College, additional training resources will be available. The first year will focus on training and developing computational models, while final years are dedicated to data analysis, thesis writing and developing independence in research.
This project is open to self-funded UK and international applicants. We are looking for a candidate with a high 2.1 or 1st class Bachelors or Masters degree in Anatomy, Biomechanics, Mechanical Engineering, or with equivalent relevant expertise.
Aftabi H., Zaraska K., Eghbal A., McGregor S., Prisman E., Hodgson A., Fels S. 2024 Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery. Computers in Biology and Medicine 169, 107887. (doi:https://doi.org/10.1016/j.compbiomed.2023.107887).
Cheng K.-j., Liu Y.-f., Wang R., Yuan Z.-x., Jiang X.-f., Dong X.-t. 2022 Biomechanical behavior of mandible with posterior marginal resection using finite element analysis. International Journal for Numerical Methods in Biomedical Engineering 38(2), e3549. (doi:https://doi.org/10.1002/cnm.3549).
Yoda N., Zheng K., Chen J., Liao Z., Koyama S., Peck C., Swain M., Sasaki K., Li Q. 2018 Biomechanical analysis of bone remodeling following mandibular reconstruction using fibula free flap. Medical Engineering & Physics 56, 1-8. (doi:https://doi.org/10.1016/j.medengphy.2018.03.008).
Zheng K., Yoda N., Chen J., Liao Z., Zhong J., Wu C., Wan B., Koyama S., Sasaki K., Peck C., et al. 2022 Bone remodeling following mandibular reconstruction using fibula free flap. Journal of Biomechanics 133, 110968. (doi:https://doi.org/10.1016/j.jbiomech.2022.110968).
If you have any questions or want to apply, please email your CV, cover letter, project title and reference number to Dr Sharp: Alana.Sharp@liverpool.ac.uk
| Supervisor title and name | Email address | Staff profile URL |
| Dr Alana Sharp | Alana.sharp@liverpool.ac.uk | Dr Alana Sharp | Our people | University of Liverpool |
| Prof Andrew Schache | Andrew.Schache@liverpool.ac.uk | Professor Andrew Schache | Our people | University of Liverpool |
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Your tuition fees, funding your studies, and other costs to consider.
Full-time place, per year - £5,006
Full-time place, per year - £31,248
Fees applicable to academic year 2025/26
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Dr Alana Sharp Alana.sharp@liverpool.ac.uk