Power-assisted Pedicle Screw Technique Protects Against Risk of Surgeon Overuse Injury: A Comparative Electromyography Study of the Neck and Upper Extremity Muscle Groups in a Simulated Surgical Environment

Abstract

Study design: Cadaveric.

Objective: The aim of this study was to quantify the amplitude and duration of surgeons' muscle exertion from pedicle cannulation to screw placement using both manual and power-assisted tools in a simulated surgical environment using surface electromyography (EMG).

Summary of background data: A survey of Scoliosis Research Society members reported rates of neck pain, rotator cuff disease, lateral epicondylitis, and cervical radiculopathy at 3 ×, 5 ×, 10 ×, and 100 × greater than the general population. The use of power-assisted tools in spine surgery to facilitate pedicle cannulation through screw placement during open posterior fixation surgery may reduce torque on the upper limb and risk of overuse injury.

Methods: Pedicle preparation and screw placement was performed from T4-L5 in four cadavers by two board-certified spine surgeons using both manual and power-assisted techniques. EMG recorded muscle activity from the flexor carpi radialis, extensor carpi radialis, biceps, triceps, deltoid, upper trapezius, and neck extensors. Muscle activity was reported as a percentage of the maximum voluntary exertion of each muscle group (%MVE) and muscle exertion was linked to low- (0-20% MVE), moderate- (20%-45% MVE), high- (45%-70% MVE) and highest- (70%-100% MVE) risk of overuse injury based on literature.

Results: Use of power-assisted tools for pedicle cannulation through screw placement maintains average muscle exertion at low risk for overuse injury for every muscle group. Conversely with manual technique, the extensor carpi radialis, biceps, upper trapezius and neck extensors operate at levels of exertion that risk overuse injury for 50% to 92% of procedure time. Powerassisted tools reduce average muscle exertion of the biceps, triceps, and deltoid by upwards of 80%.

Conclusion: Power-assisted technique protects against risk of overuse injury. Elevated muscle exertion of the extensor carpi radialis, biceps, upper trapezius, and neck extensors during manual technique directly correlate with surgeons' self-reported diagnoses of lateral epicondylitis, rotator cuff disease, and cervical myelopathy.Level of Evidence: N/A.