Patient-Specific 3D Printing for Thoracic Surgery
Lead Research Organisation:
King's College London
Department Name: Imaging & Biomedical Engineering
Abstract
Lung cancer is the most common cause of cancer death in the UK. There are approximately 45,000 new cases per year and the annual cost to the UK economy is an estimated £2.4b. Lung lobectomy is the most common treatment. Patients with advanced cancer involving the chest wall require en-bloc resection surgery and chest wall reconstruction. Accurate reconstruction provides protection, reduced complications and correct respiratory mechanics. The second method to perform a lobectomy is video assisted thoracoscopic surgery (VATS), offering reduced pain and length of recovery. Physical simulators can be used for VATS training to provide a realistic simulation environment. This project aimed to produce and clinically validate a novel patient-specific rib prosthesis based on 3D reconstruction of the chest wall from the patient's medical images. A silicone mould made from 3D printed models was used to create bone-cement prostheses for chest wall reconstruction. This method was used on 6 patients, and evaluated by the tracking of their chest wall motion. The personalised prostheses offered patients a perfect replication of their chest wall, providing improved breathing mechanics and cosmetics while maintaining low production cost. A novel 3D printing technology was investigated to print PEEK prostheses that demonstrate similar mechanical properties as bone and can be implanted into the body. The combination of imaging and 3D printing was also used to develop a model of the right side of the chest to simulate VATS for surgical training. 3D representations of the heart, hilum, lung, trachea, right bronchi and right ribs were constructed and evaluated by thoracic surgeons during a VATS training. The model was able to recreate the human anatomy with high realism and accurately simulate a lobectomy. Electrical conductivity and blood flow were the two additions required to improve the model for the use of energy devices on it and for a more realistic simulation of the VATS surgery.
People |
ORCID iD |
| Kawaldeep Rhode (Primary Supervisor) | |
| Tonia Pontiki (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513064/1 | 01/10/2018 | 30/09/2023 | |||
| 2125387 | Studentship | EP/R513064/1 | 01/10/2018 | 31/07/2022 | Tonia Pontiki |
| Description | Lung cancer is the most common cause of cancer death in the UK. Patients diagnosed in the early stages can undergo en-bloc resection surgery. The chest wall is resected to guarantee a good resection margin and has to be reconstructed. Adequate repair prevents lung herniation which would otherwise cause paradoxical breathing, shortness of breath and possibly recurrent infections. Current practice is to perform the repair using bone cement. The aim of this project was to develop and clinically test a novel patient-specific rib prosthesis based on accurate 3D reconstruction of the chest wall from the patient's medical images. The prosthesis is made using the same material previously used, i.e. methyl methacrylate, adding the advantage of having a perfect 3D model of the chest wall, providing lung protection, better stability, improved breathing mechanics and better cosmetics while maintaining the low procedure cost. -The new method of reconstruction using 3D printing, a patient-specific silicone mould and bone cement implants, was developed and approved by the Clinical Governance Unit at Guy's & St. Thomas' NHS Trust. The method started being used in patient surgery in 2018. To evaluate the reconstruction method, a technique was developed using photogrammetry to track the chest wall surface in real-time to assess breathing symmetry, and was validated on healthy volunteers. This study was approved as an audit project. -A statistical shape model of the ribs from historical patient imaging data was developed and evaluated for automated segmentation of new cases. A program was developed, using the software Matlab, for the automatic generation of rib models based on patient characteristics: rib number, age, gender, height and weight. -The method of reconstruction led to the investigation of the next step: develop a novel 3D printing technology to print a negative rib model, a silicone mould. A silicone printer had to be built to be able to achieve this. This includes research on material properties, coding and mechatronics. -The third step for the reconstruction technique would be to directly print the implants, without using a mould. Hence, the use of 3D printers to directly print the rib models as a biological scaffold is being investigated. The above skills acquired while building the silicone printer are put into practice to build a high temperature 3D printer that can directly print the rib implants in a material that poses same mechanical properties as bone, is biocompatible and can be sterilised. This printer is currently under construction. Once it is finalised the the biocompatible implants can be 3D printed, an ethics approval application will be submitted for this new method of chest wall reconstruction. -Through the collaboration with the thoracic surgeon who is the third supervisor of this project, another project started. A model of the right side of the chest was developed to simulate Video Assisted Thoracoscopic Surgery for surgical training. The approach was to create a physical life size simulator which can replicate lung lobectomy surgeries to a high level of accuracy and realism whilst being affordable. The simulator has been completed and the aim is for it to be integrated into medical teaching programmes and preoperative planning of complicated surgeries. |
| Exploitation Route | - The current method of patient-specific reconstruction of the chest wall can be approved as the standard of care and be used in other hospitals in the UK where thoracic surgeons reconstruct the chest wall using methyl methacrylate. - The program that generates rib models based on patient characteristics can also be used as part of the above method. So there would be a clinical protocol developed, including the creation of the digital model of the ribs to be resected and reconstructed, using the Matlab program we created, and then the creation of the physical rib implants using the patient specific silicone mould. - The silicone printer we are building can be used to create anatomical phantoms for research, training and diagnosis. It can also be used to print prosthetics. - High temperature materials are used in many industries, not only in healthcare. Due to their high melting points and high strength they are commonly used in mechanical engineering. The high temperature printer we are building can be used to print parts for ie robotics, but also to print bone implants for several parts of the body. - Artificial simulators are a great alternative to cadavers since they are an accurate representation of the human anatomy, without having the ethical issues or the high cost of a cadaver. The chest simulator can be used for the education of medical students, training of surgeons and even the education of patients for them to have a better understanding of their procedure. This model can be used to train surgeons but also to train the theatre team to face emergency situations in real life such as acute bleeding or emergency robotic system failure, which are not currently part of the robotic surgery training pathway. |
| Sectors | Education,Healthcare,Manufacturing, including Industrial Biotechology |
| Description | We have developed a novel method to produce a patient-specific chest wall prosthesis for patients undergoing resection surgery. This technology was approved by the Clinical Governance Unit at Guy's & St. Thomas' NHS Trust and is now in routine use for these types of patients within the Trust. To-date ten patients have undergone chest wall resection and reconstruction using the novel method. Preoperative CT scans are used to create a 3D model of the ribs and sternum to be resected and reconstructed, using image processing tools. The anatomical models are 3D printed in low-cost polylactic acid and used to produce a silicone mould. The mould is sterilised, and filled with polymethylmethacrylate cement during surgery, to create the customised prosthesis, which is implanted together with a prolene mesh. To evaluate the reconstruction method, photogrammetry was used to assess the respiratory mechanics function of patients who underwent chest wall reconstruction. This was approved by the ethics committee as an audit project. Photogrammetry involved tracking of the chest wall motion; this was used as it provides radiation-free, non-invasive real-time 3D tracking and has previously been used in radiotherapy, surgery and orthopedics. On post-operative follow-up, we found that patients treated using the novel technology had better respiratory mechanics, lower hospital stay and less morbidity than case-matched controls. Also the novel implants resulted in a better cosmetic outcome. The personalised prostheses offered patients a perfect replication of their chest wall, providing improved breathing mechanics and cosmetics while maintaining low production cost. The current method of chest wall reconstruction is only being used at Guy's hospital. A case series paper has been submitted in the Annals of Thoracic Surgery and is currently under review. If the paper is published, this method might become more widely known and could be adopted as the standard of care in more hospitals internationally. Moreover, we are currently working on the next step of this project, which involves the direct printing of chest wall implants. Instead of using 3D printing to create a mould for the prosthesis, the rib prosthesis will be directly 3D printed in a biocompatible material. This method would be an improvement of the current one and it will be submitted for ethics approval. If the application is successful, there will be a clinical trial. That method will be patented and could potentially become the standard of care internationally. That method of bone production, if proven successful, could also be used for the production of other bony structures such as cranial or maxillofacial implants. This research involves a second project. The combination of imaging and 3D printing was used to develop a model of the right side of the chest to simulate VATS for surgical training. The approach was to create a physical life size simulator which can replicate lung lobectomy surgeries to a high level of accuracy and realism whilst being affordable. The chest simulator model was already used and evaluated by thoracic surgeons during two VATS training sessions that took place at Guy's hospitals. The model was able to recreate the human anatomy with high realism and accurately simulate a lobectomy. Existing artificial physical simulators do not provide an accurate and detailed representation of the human anatomy, lacking the mimicking of different tissue characteristics, blood flow and electrical conductivity. Wet lab trainings are run by companies such as Medtronic or Cambridge Medical Robotics. However, animal and cadaveric tissues involve a high cost. The model developed in this study provides the accurate human anatomy without the animal- or cadaver-related ethical and high cost implications. Based on the feedback received in previous training sessions, modifications were made to the model and the final version of the simulator will be used in more training at Guy's hospital to record results and adopt this model as part of the official training pathway. Intuitive has also agreed to run a trial with the DaVinci robot on the chest simulator. Due to COVID19 the trials have been postponed until further notice. |
| First Year Of Impact | 2018 |
| Sector | Education,Healthcare,Manufacturing, including Industrial Biotechology |
| Description | Biomedical Engineering and Guy's and St Thomas' NHS Foundation Trust |
| Organisation | Guy's and St Thomas' NHS Foundation Trust |
| Country | United Kingdom |
| Sector | Public |
| PI Contribution | We are collaborating with a consultant thoracic surgeon on the project of the patient-specific chest wall reconstruction. Since 2018 we have been making the chest wall prosthesis for any patient that undergoes chest wall resection and reconstruction surgery at Guy's Hospital. We also provided the chest simulator models for the thoracic registrars to use during two of their training at Guy's Hospital. |
| Collaborator Contribution | All the results for the chest wall reconstruction project have been collected from Guy's Hospital patients. The largest part of this research depends on the patient data which we get through this collaboration. The chest simulator will be used by surgeons at GSTT and all data for the simulator's evaluation will be recorded during the training sessions of those surgeons. |
| Impact | - Chest wall reconstruction developed in this study, has been used on 10 patients at Guy's Hospital. - Publication 10.1055/s-0039-1678611 - Another paper has been submitted for publication to the Annals of Thoracic Surgery, which is a case series on the patients who underwent surgery at Guy's Hospital. - Publication 10.1053/j.semtcvs.2020.10.002 - Physical Chest Simulator For Minimally Invasive Thoracoscopic Surgery - its use in surgical training at Guy's Hospital |
| Start Year | 2018 |
| Title | Chest wall, 3D patient-specific MMA prosthesis |
| Description | Lung cancer is the most common cause of cancer death in the UK. There are approximately 45,000 new cases per year and the annual cost to the UK economy is an estimated £2.4b. Lung lobectomy is the most common treatment. Patients with advanced cancer involving the chest wall require en-bloc resection surgery and chest wall reconstruction. Accurate reconstruction provides protection, reduced complications and correct respiratory mechanics. In this study, a novel 3D technique was developed for the chest wall reconstruction of patients undergoing resection surgery for primary or secondary cancer involving the chest wall. The use of this 3D reconstruction was approved by the Guy's Hospital Research and Development department and started being used in 2018. Preoperative CT scans are used to create a 3D segmentation of the ribs and sternum using image processing tools. The anatomical models are 3D printed in low-cost polylactic acid and used to produce a silicone mould. The mould is sterilised, and filled with polymethylmethacrylate cement during surgery, to create the customised prosthesis, which is implanted together with a prolene mesh. On post-operative follow-up, we found that patients treated using the novel technology had better respiratory mechanics, lower hospital stay and less morbidity than case-matched controls. Also the novel implants resulted in a better cosmetic outcome. The en-bloc resection surgery is a rare procedure, and this method has been used on 10 patients. This preliminary study demonstrated the feasibility to create a patient specific chest wall prosthesis which is safe, easily and quickly manufactured, improves cosmetic and functional results for patients undergoing an en-bloc resection surgery. The project is now funded by the EPSRC Doctoral Training Programme at KCL. |
| Type | Therapeutic Intervention - Medical Devices |
| Current Stage Of Development | Small-scale adoption |
| Year Development Stage Completed | 2018 |
| Development Status | Under active development/distribution |
| Impact | This technology was approved by the Clinical Governance Unit at Guy's & St. Thomas' NHS Trust and is now in routine use for these types of patients within the Trust. To-date ten patients have undergone chest wall resection and reconstruction using the novel method. The novel technology has already directly benefited ten patients undergoing open surgery. This is an on-going impact. New findings in the manufacture of silicone based products from 3D printing has been translated into other projects such as the manufacture of cardiac valves for assessment of valve disease in patients. This technology has led to a separate project for the creation of a physical chest simulator for minimally invasive thoracoscopic surgical training. These models have been already deployed in a training session by GSTT and Medtronic for initial evaluation. |
| Title | Physical Chest Simulator For Minimally Invasive Thoracoscopic Surgery |
| Description | Surgery is considered the best approach for lung cancer treatment. The lung cancer gold standard operation is a lobectomy. That procedure involves the removal of a single lobe of the lung. There are two different approaches for a lung lobectomy; a thoracotomy or a Video-assisted Thoracoscopic Surgery (VATS) or Robotic assisted thoracic surgery (RATS). The second method, offers reduced pain and length of recovery. Physical simulators can be used for VATS training to provide a realistic simulation environment. The combination of medical imaging and 3D printing was also used to develop a model of the right side of the chest to simulate VATS lobectomy for surgical training. 3D representations of the right heart, hilum, lung, trachea, right bronchi and the 2nd to 10th right ribs were constructed and evaluated by thoracic surgeons during a VATS lobectomy training. The aim was to develop a cost effective, life-size artificial simulator which can replicate video-assisted thoracoscopic or robotic lobectomy to a high degree of reproducibility, accessibility and fidelity. |
| Type Of Technology | Physical Model/Kit |
| Year Produced | 2020 |
| Impact | After the development, the goal was to assess whether training with such a simulator will improve and speed up the learning curve of a trainee thoracic surgeon, reducing future intraoperative complications and improving outcomes. This model can be used to train surgeons but also to train the theatre team to face emergency situations in real life such as acute bleeding or emergency robotic system failure, which are not currently part of the Intuitive (DaVinci robot) training pathway. The model has already been used in two thoracic surgical training session in Guy's Hospital. Surgical instrument companies have expressed interest in the model, as part of the training sessions they run for thoracic registrars. This chest simulator can be adopted as part of the standard training process for surgical registrars, initially at GSTT NHS Trust, and potentially nationally and internationally. |
| Title | Rib generating program, based on patient characteristics |
| Description | This is a Matlab program used for the optimisation of the method to generate 3D digital models of patient-specific rib prosthesis. The developed code can generate a rib mesh according to input patient characteristics: rib number, age, height, weight and gender. The Matlab code is currently being used to generate rib meshes based on the characteristics of 12 patients. The resulting rib meshes will be compared with the rib meshes of those 12 patients generated by segmenting their CT scans. |
| Type Of Technology | New/Improved Technique/Technology |
| Year Produced | 2021 |
| Impact | The program is currently under evaluation and the results are being processed. This can be adopted as the standard method of patient-specific rib model generation. This method is way more time efficient, but also less labour intensive compared to the current method being used to generate the rib models that are used to make the rib implants used for the chest wall reconstruction surgery. If this method using the Matlab program becomes the standard, it will be used to make the rib prostheses of patients undergoing chest wall reconstruction at Guy's Hospital. Its use could expand further to more hospitals in the future. |