One will spend only 20 months in jail, while the other escaped with a community service order after being sentenced in the Brisbane District Court on Friday.

Brock Prime, then aged 29, suffered a severe head injury that left his brain exposed when he was assaulted by a group of men on the side of the M1 motorway near Yatala on February 24, 2018.

Jonathan Christopher Lawerence, 29, pleaded guilty to one count of grievous bodily harm while Jordan Jonathan Baklas, 30, pleaded guilty to one count of assault occasioning bodily harm.

Charges against 31-year-old Ryan David Hallifax were dropped.

Lawerence was sentenced to five years' jail, suspended after 20 months, operational for five years.

Baklas was ordered to perform 100 hours of community service.

Police at the time said up to 13 people may have been in a white van involved in the incident.

Officers reported the van and Mr Prime's black Subaru Forester came close to colliding on the M1 around Coomera, sparking a "cat and mouse game" during which the vehicles ducked and weaved through traffic in wet conditions before pulling over.

The court was told Mr Prime used a concreting trowel to hit the van before the melee erupted, and he was eventually struck with the same trowel.

According to social media posts at the time, Mr Prime's family was told by doctors he had suffered a fracture to his skull in the attack.

Australian Associated Press