Cervical spine extension associated with reduced anatomical risk of spinal canal perforation in a cadaveric study

Dry needling (DN) is an effective treatment for cervical pain, but its invasive nature carries risks of adverse events like spinal canal perforation. This study aimed to determine whether cervical spine positioning influences the risk of inadvertent spinal canal perforation during a deep mid-cervical DN technique. Using a flexible human cadaver model, an experienced physical therapist performed 20 pragmatic needle insertions (0.30 mm × 60 mm) targeting the C5 lamina, with 10 attempts executed in a neutral position and 10 attempts in 10 degrees of relative extension. A clinical pistoning maneuver was performed, and final needle placement was independently verified via ultrasound. Spinal canal perforation occurred in 20% of attempts (2 out of 10) in the neutral position when the initial firm end feel was lost during pistoning, leading to full needle advancement. Zero perforations occurred in the extension condition. A significant difference in needle depth was identified between the perforation and non-perforation groups (p = .02). These findings indicate that placing the cervical spine in relative extension may reduce anatomical surface area and minimize the risk of spinal canal perforation.