Effects of transcranial direct current stimulation on surgical skills acquisition: a systematic review

Background: Surgical training is opportunity based, and multiple factors including exposure time, case volume and simulation training contribute to achieving competencies. We aimed to evaluate the effects of transcranial direct current stimulation (TDCS) as an adjunct to attain surgical skills faster. Methods: A registered systematic review (PROSPERO number CRD42020211985) of randomized trials (RCTs) on Biosis, Cochrane Central, EMBASE, MEDLINE, PsycINFO databases was carried out. Studies included compared active TDCS to sham stimulation in a surgical task involving trainees. Outcomes were grouped into four domains to overcome the heterogeneity of study outcomes: speed of skills acquisition; proficiency, i.e. ability to achieve a pre-determined score/level of proficiency; accuracy and error reduction; and composite outcomes involving more than one domain. Results: Four RCTs were identified involving 143 participants in total (61 sham, 82 TDCS). All studies utilized simulation training: three in laparoscopic training (peg transfer and pattern cutting), and one in neurosurgery training (tumour resection exercise). The mean age of the participants was 24.5 1.5 years, 58% (n=83) were female and 92% (n=131) were right hand dominant. Use of TDCS was associated with improved speed of skills acquisition, proficiency, accuracy and a less steep learning curve. This performance advantage was sustained for at least 6 weeks. Conclusions: TDCS may be a useful, safe adjunct for surgical simulation training. It is associated with improved skills acquisition in both laparoscopic and neurosurgical training tasks. Further research is needed to evaluate its use in other surgical specialties.