William Wesley Styron has filed suit against the boybands in Tennessee over an incident that allegedly occurred at the FedEx Forum in Memphis in June 2011.
Styron contends that he was preparing for a concert when he stepped into a large unmarked hole in the stage and fell 13 feet, according to TMZ.
The man claims he suffered a brain injury and also fractured his skull in the tumble, which he blames on negligence.
Styron is apparently seeking $5m ($3.2m) in damages to cover medical bills and other costs.
A spokesperson for the New Kids on the Block and Backstreet Boys tour has denied responsibility for the incident.
The NKOTBSB tour wraps up in Hershey, PA on August 18 after more than a year on the road.
Watch New Kids on the Block and Backstreet Boys perform a medley below: