Receive an email when new articles are posted on Please provide your email address to receive an email when new articles are posted on . We were unable to process your request. Please try again later. If you continue to have this issue please contact customerservice@slackinc.com. In this video, tubular dilators are used to gently subperiosteally elevate the paraspinal musculature in unilateral biportal endoscopy, creating the surgical working corridor. According to Puranjay Gupta, BS; Aimen A.