"He also sustained bruising of his brain due to the impact as well as vocal cord damage. At this stage the full extent of his injuries is unknown as well as the period of rehabilitation.
"He is breathing on his own but with difficulty as one of the nerves controlling his diaphragm has been damaged. He has limited movement of his left side due to the lack of oxygen to the brain however this is showing signs of improvement. The right side, which is being affected by nerve damage, is also limited. He is able to move his leg and squeeze his hand, but there is no movement of his arm."
It will be some time before the long-term effects are known, but the update says with continued rehabilitation it is hoped all functionality will return over time.
ADMIN POST:
The overwhelming support for Keagan continues. Thank you Mark Cavendish for your encouraging words ...
#KeepFightingKeagz
Posted by Keagan Girdlestone on Thursday, June 16, 2016
The international cycling community has rallied around Girdlestone.
Both Tour de France winner Chris Froome and top sprinter Mark Cavendish have left videos of support on his Facebook page. Girdlestone rides for the junior feeder team of Cavendish's professional squad Dimension Data.
The young cyclist is considered a rising star who may have slipped through the grasp of New Zealand cycling.
The Girdlestone family moved to Christchurch from Pretoria four years ago.
Keagan Girdlestone, whose 26-year-old brother Dylan is also a professional cyclist, burst into prominence in 2014 as the youngest winner of the 100km Christchurch to Akaroa race when he was just 16.
He finished fourth at the junior men's time trial in Virginia last year, riding under the South African flag.
Success in Australia helped fast track him into the professional scene but tragedy has struck almost straight away.