The impact of prefrontal transcranial direct-current stimulation on technical performance and cortical activation in surgeons
Creators: name: Patel, Ronak
Publisher: name: Imperial College London
Year: 2022

description: In the field of surgery, clinical and patient outcomes are highly dependent on surgical technical skills, and therefore surgical training. However, surgeons in training now face several obstacles to their development and attaining expert proficiency is made more challenging with the advent of training reforms, reduced operative exposure and the introduction of complex surgical procedures. The prefrontal cortex (PFC) has a well-established role in the development of surgical skills with greater dependence in early training and a subsequent attenuation with progression of expertise. Transcranial direct-current stimulation (tDCS) is a novel neuroscience method which has demonstrated both motor and cognitive behavioural enhancement outside of the surgical setting. The purpose of this thesis is to investigate the impact of tDCS on improving surgical technical skills and explore the associated impact on cortical haemodynamics. The first study reveals an improvement in surgical performance when tDCS was applied to the PFC in students performing an open knot-tying task, with greatest improvements observed in lower-skilled students. In the next study, when asked to perform basic laparoscopic skills tasks, tDCS did not appear to be associated with such significant improvements. The third study demonstrates surgical skill improvement with tDCS, evident through greater knot-tensile strength and accuracy on a robotic suturing task. Behavioural improvements could represent greater neural efficiency, with tDCS offsetting the dependence on PFC resources during surgical skill learning, especially in the early stages. However, these studies did not investigate the underlying neural mechanisms associated with performance improvement. Therefore, to delineate the neural correlates of tDCS and surgical skill enhancement, tDCS was then combined with functional near-infrared spectroscopy (fNIRS) in the same experimental IV paradigm in which both junior and senior trainees performed a laparoscopic suturing task. Significant improvements were observed in the performance scores in junior trainees coupled with greater PFC attenuation and more SMA upregulation Given the potential controversial nature of surgical skill enhancement through neurostimulation, the final chapter explores the opinions of patients, students and clinicians on using tDCS in this setting. There was an overall acceptance of using tDCS based skills training provided certain standards and assurance with regards to safety and efficacy were met. This thesis highlights the potential of tDCS as a training adjunct to improve surgical technical skills, especially in more junior and lower-skilled trainees. When combined with brain imaging, it suggests there may be earlier manifestation of neural signatures associated with more senior trainees. Whilst the data here suggest that tDCS could be a feasible and acceptable addition to surgical training, further work is required before its efficacy and long-term safety are established. Furthermore, its impact on real-world clinical outcomes and the benefit to the patient needs to be explored in much greater depth prior to any discussions about its implementation in surgical training.