Virtual reality in urology
Article first published online: 3 AUG 2004
Volume 94, Issue 3, pages 255–257, August 2004
How to Cite
Nedas, T., Challacombe, B. and Dasgupta, P. (2004), Virtual reality in urology. BJU International, 94: 255–257. doi: 10.1111/j.1464-410X.2004.04975.x
- Issue published online: 3 AUG 2004
- Article first published online: 3 AUG 2004
With ever-increasing pressures on surgical performance from both an expectant and litigious public and medical regulatory bodies, the surgical profession is constantly looking for training systems that are novel, reproducible and validated. In urology, trainees are operating less than ever before, because there are fewer patients requiring surgery. The percentage of urological referrals requiring surgery was 30–40% in 1980 and has now fallen to ≈ 10%. The reasons for this include earlier diagnosis and subsequent increased suitability for minimally invasive therapies (e.g. prostate brachytherapy), and pharmacological advances, particularly within the fields of BPH and erectile dysfunction. The European Working Time Directive is further restricting the actual time available for surgical training. This limits the weekly work for all doctors to a maximum of 48 h from August 2004, and it has been suggested that the training time available during the residency years will decrease from 30 000 to 8000 h as a consequence . The higher the hospital and surgeon volume, the less the operative mortality ; this principle also applies to minimally invasive urology in general and laparoscopy in particular.
For many centres the current training options are either ‘dry’ or ‘wet’ laboratories; the former, which are essentially covered boxes within which surgical tools are manoeuvred, lack authenticity, as they involve isolated or replica tissues/organs. ‘Wet’ laboratories using live or freshly killed animals, although recognized training methods are currently prohibited in the UK by animal legislation, and travel to other countries for such training is expensive and time-consuming. New virtual reality (VR) systems that provide realistic operative conditions with no risk to patients are required. Such systems must be validated to allow clear discrimination between those with previous experience of a procedure and relative novices. Satava and Fried  have produced a uniform framework for error assessment, and hence validation, that is applicable to all VR systems. VR offers a new alternative and urology, with an increasing emphasis on minimal invasion, is particularly suited to this method.
In 1991, Dr Robert Mann, the pioneer behind the first VR system, said that ‘VR is the ultimate surgical simulator’. A decade later there are several manufacturers competing to develop increasingly realistic VR systems. In endourology the URO Mentor (Simbionix, Israel) is a trainer for flexible cystoscopy, ureterorenoscopy and percutaneous nephrolithotomy. It has been validated during a flexible cystoscopy course, showing a significant reduction in procedure time after training on the system . It allows exposure to a wide range of adaptable procedures with realistic virtual fluoroscopy images. Available tools include baskets, graspers, guidewires and intracorporeal lithotripters, which can be used for stone disintegration and removal of fragments. The same ureteroscopy system, evaluated by Jacomides et al. indicated a 50% reduction in procedure time by novice medical students after VR training. Their performance became comparable with that of urological residents who had completed a year of training.
VR training leads to faster adaptation to the novel psychomotor restrictions encountered by laparoscopic surgeons. In laparoscopy there are several VR simulators, e.g. the MIST-VR (Mentice, Gotenberg, Sweden). Using this device, laparoscopists can practise basic tasks such as ‘pick and place’, suturing and diathermy, before moving on to entire procedures. At present VR laparoscopic cholecystectomy is the only complete module available. The current focus is on fine-tuning the haptic feedback of these systems, whilst continually improving the graphics software. A collaborative venture between Guy's and Mentice is developing a VR laparoscopic nephrectomy simulator. This will allow both ‘pure’ laparoscopic and hand-assisted laparoscopic nephrectomy by ‘virtual glove’ technology.
The objective assessment of surgical performance is relatively straightforward with VR systems because they can measure metrics, i.e. a quantity reflecting a characteristic of a network, e.g. measuring different items or periods. VR systems allow the recording of both simple metrics (time of procedure, economy of movement, collisions) and more complex metrics (diathermy errors, clip errors, grasping errors). Using these variables it is possible to compare specific surgeons, surgeons of different grades and to measure individual improvement over various tasks.
PROS AND CONS
Surgeons historically used to speak of ‘see one, do one, teach one’ with regard to surgical training, but this well-loved phrase is no longer appropriate. VR systems have the obvious advantage over traditional apprenticeship, as trainees can acquire skills with no risk to patients. In addition the systems can be customised to the needs of individual trainees, and cases with differing anatomy and complexity can be attempted. Crucially, trainees can practise the more difficult steps (e.g. dissecting the renal vessels) repeatedly, and their response when faced with a serious but hopefully rare complication such as a vascular or bowel injury. Thus training efficiency should improve, and it is believed that training costs can be reduced by up to $48 000 per resident.
The disadvantages of any VR system include some reduced authenticity compared with an actual procedure, as haptics and graphic resolution still need to be improved. In addition there is always the potential danger that trainees will become more skilled at the virtual operation than they are at the real thing. There is an initial capital outlay to develop, purchase and maintain a system, but this may be offset by a reduction in overall training costs.
As VR becomes increasingly advanced it is likely that high-resolution CT/MRI images will be integrated into systems, such that procedures could be tailored to individual patients. As a result a surgeon could practise a virtual operation the day before the real procedure on the patient. In addition, exponents of VR feel that it is likely to become an integral part of aptitude testing and training for urological surgeons . Indeed, it is possible that VR assessment may become a mandatory requirement in the revalidation of surgeons by the professional governing bodies. In the technology-driven speciality of urology, where minimal invasion is gradually becoming the method of choice, we have the opportunity to pioneer and develop VR systems to benefit the new generation of surgeons.
The Guy's and St. Thomas’ Charitable Foundation.