Hypothesis

The use of cartilage compensated virtual standing CT images for pre surgical planning improves the reliability of preoperative planning.

INTRODUCTION. Simulation plays an important role in surgical education and the ability to perfect surgical performance. Simulation can be enhanced by adding various layers of realism to the experience. Haptic feedback enhances the simulation experience by providing tactile responses and virtual reality imagery provides an immersive experience and allows for greater appreciation of three-dimensional structures. In this study, we present a proof-of-concept haptic simulator to replicate key steps of a cervical laminoplasty procedure. The technology uses affordable components and is easily modifiable so that it can be used from novice through to expert level. Custom models can be easily added ensuring the simulator can be used in a wide range of orthopaedic applications from baseline education through to day of surgery pre-operative simulation. METHOD. We used the Unity Game Engine, the 3D Systems “Touch” Haptic Feedback Device (HFD), and a Meta Quest VR headset. Our system uses a number of complex algorithms to track the shape and provide haptic feedback of a virtual bone model. This allows for simulation of various tools including a high-speed burr, Kerrison rongeur and intraoperative X-rays. RESULTS. Our simulator replicates the tactile sensations of bone-burring tasks. Although we focused on the cervical laminoplasty procedure, the system can load data from CT scans, enabling the simulation of multiple other procedures. The parts cost of our system, $10,000 NZD, is a fraction of the cost of traditional surgical simulators. DISCUSSION. Our simulator reduces financial barriers to accessing orthopaedic simulators. Trainees can perform hands-on practice without compromising patient safety. The immersive nature of VR, combined with realistic haptic feedback, enables trainees to develop the dexterity and three-dimensional understanding of detailed bony work. Further refinements are needed before we can perform validation studies on our system. CONCLUSIONS. We present an affordable surgical simulator capable of simulating bony surgical procedures in a VR environment using haptic feedback technology and consumer-grade components. ACKNOWLEDGEMENTS. This research was made possible by the generosity of the Wishbone Trust

Revision hip arthroplasty requires a comprehensive appreciation of abnormal bony anatomy. Advances in radiology and manufacturing technology have made three-dimensional representation of actual osseous anatomy obtainable. These models provide a visual and tactile reproduction of the bony abnormality in question. Life size three dimensional models were manufactured from CT scans of two patients. The first had multiple previous hip arthroplasties and bilateral hip infections. There was a pelvic discontinuity on the right and a severe postero-superior deficiency on the left. The second patient had a first stage revision for infection and recurrent dislocations. Specific metal reduction protocols were used to reduce artefact. The dicom images were imported into Mimics, medical imaging processing software. The models were manufactured using the rapid prototyping process, Selective Laser Sintering (SLS). The models allowed accurate templating using the actual prosthesis templates prior to surgery. Acetabular cup size, augment and buttress sizes, as well as cage dimensions were selected, adjusted and re-sterilised in advance. This reduced operative time, blood loss and improved surgical decision making. Screw trajectory simulation was also carried out on the models, thus reducing the chance of neurovascular injury. With 3D printing technology, complex pelvic deformities can be better evaluated and can be treated with improved precision. The life size models allow accurate surgical simulation, thus improving anatomical appreciation and pre-operative planning. The accuracy and cost-effectiveness of the technique were impressive and its use should prove invaluable as a tool to aid clinical practice

Introduction. Support cages are often used for reconstruction of acetabular bone defects in revision total hip arthroplasty. A Burch-Schneider cage is one of the most reliable systems that has shown good clinical results. It has an ischial flange and an iliac plate for screw fixation to the ilium. It is sometimes necessary to bend the flange or the plate to fit the shape of the peri-acetabulum. However, the frequency, indications, and characteristics of bending the flange or plate have not been reported. To clarify them, a simulation study was conducted. Materials and methods. Twenty-five cases with acetabular bone defects of Paprosky type 2, 3, or 4 were the subjects of this study. A 3D template surgical simulation was conducted using 3D surface models of the Burch-Schneider cage and acetabulum. The size of the cage was determined by the size of the cavitary bone defect. Placement of the cage was performed in two ways. One was the iliac plate fitting method, in which fitting of the iliac plate to the ilium was performed first, followed by bending of the ischial flange to keep the flange in the center of the ischium. When bending of the flange was needed, it was bent at the base. The other method was the ischial flange fitting method, in which the ischial flange was inserted from the center of the ischium, followed by bending of the iliac flange to adapt to the ilium. When bending of the plate was needed, it was bent at the base. In both methods, the direction and angle of bending were measured. Results. In the iliac plate fitting method, the cage adapted the acetabulum without bending the ischial flange in 12 cases, and with lateral bending in 11 cases. The bending angle was less than 30° in 8 cases. Three cases required more than 30° of bending and there were also 2 cases which were impossible to fit the acetabulum even with bending the ischial flange. This was due to the large bone defect at the superolateral region of the acetabulum. In the ischial flange fitting method, the cage adapted the acetabulum without bending in 12 cases. The remaining 13 cases required less than 30° of iliac plate lateral bending. Discussion. The iliac plate fitting method is a clinically oriented method since the insertion position of the ischial flange is determined after fitting the provisional cage with an iliac plate. However, in cases with a large bone defect in the superolateral region of the acetabulum, some were impossible to fit. On the other hand, with the ischial flange fitting method, the cage could fit all types of acetabular defects. This suggests that, even in cases with a bone defect in the superolateral region of the acetabulum, the Burch-Schneider cage is a usable instrument. Conclusion. The half of the cases required lateral bending of the ischial flange or iliac plate. If there is a large bone defect at the superolateral region of the acetabulum, the iliac plate may need to be bent

Skills simulation is increasingly used as a training tool in postgraduate surgical training. Trainee's perception of the value of this experience has not previously been investigated. Our aim was to investigate the value of surgical simulation training delivered by an arthroscopy skills course. We constructed a subject-specific, self-assessment questionnaire based around the ISCP Peer Assessment Tool. The questionnaire was administered to candidates before and after attending the Plymouth Arthroscopy Skills Course. Participant demographic data was recorded. Questionnaire data was interrogated to give an overview of the course, as well as the benefit of site-specific skills stations. Statistical analysis showed the data to be normally distributed. The paired T-test was used to compare mean values. Twelve surgical trainees attended the course – CT2 trainees (n=4); ST3 trainees (n=7); ST4 trainee (n=1). 11 candidates completed both administered questionnaires giving a 92% response rate. The global mean score at the beginning of the course was 2.39. The global mean score at the end of the course was 3.90. The mean improvement was 1.51 (p<0.01; 95% CI = 0.96–2.07). Skill station specific scores all showed improvement with the greatest effect in wrist arthroscopy. CT trainees had a lower mean score compared to ST trainees. Both groups completed the course with similar mean scores. This study shows that arthroscopy simulation improves trainee-reported ratings of surgical skill. It also shows that less experienced candidates derived the greatest benefit from the training. Further research is required to compare self-assessed performance against objective benchmarks using validated assessment tools

Skills simulation is increasingly used as a training tool in postgraduate surgical training. Trainee's perception of the value of this experience has not previously been investigated. The aim of this investigation was to investigate the value of surgical simulation training delivered by an arthroscopy skills course. We constructed a subject-specific, self-assessment questionnaire based around the ISCP Peer Assessment Tool. The questionnaire was administered to candidates before and after attending the Plymouth Arthroscopy Skills Course. Participant demographic data was recorded. Questionnaire data was interrogated to give an overview of the course, as well as the benefit of site-specific skills stations. Statistical analysis showed the data to be normally distributed. The paired T-test was used to compare mean values. Twelve surgical trainees attended the course – CT2 trainees (n=4); ST3 trainees (n=7); ST4 trainee (n=1). 11 candidates completed both administered questionnaires giving a 92% response rate. The global mean score at the beginning of the course was 2.39. The global mean score at the end of the course was 3.90. The mean improvement was 1.51 (p<0.01; 95% CI= 0.96-2.07). Skill station specific scores all showed improvement with the greatest effect in wrist arthroscopy. CT trainees had a lower mean score compared to ST trainees. Both groups completed the course with similar mean scores. This study shows that arthroscopy simulation improves trainee-reported ratings of surgical skill. It also shows that less experienced candidates derived the greatest benefit from the training. Further research is required to compare self-assessed performance against objective benchmarks using validated assessment tools