"significantly prior" is correct and can be used in written English.
It means something that happened or existed before a particular point in time and had a significant impact or influence. Example: The company's profits have been declining significantly prior to the CEO's resignation.
It may change significantly prior to launch, he said.
Yet when they checked weather records, none of these factors fluctuated significantly prior to the storm.
Pandora follows in the footsteps of Fusion-io, LinkedIn and Yandex, which all increased their pricing significantly prior to going public.
Significant concentration reductions due to dispersion occur only if the source concentrations decrease significantly prior to the arrival of the contaminant at the groundwater table.
The increase of Chl-a concentration also shows one to one relation with the increase of surface latent heat flux (SLHF) which is found to increase significantly prior to the earthquake events.
And according to Khan and Skinner, the volume of supporters' Twitter chatter and of propaganda flowing out of its central command had slowed significantly prior to Orlando.
However, the length of total clinical follow-up before and after software upgrade was significantly longer prior software upgrade (193 ± 85 days prior upgrade vs. 141 ± 54 after upgrade; P < 0.001).
"Notwithstanding the pain and injury allegedly caused by the defendant, his actions were relatively brief in duration, apparently impulsive, reactive in nature and, significantly, occurred prior to the whistle terminating play".
Results showed that our proposed model significantly outperformed prior methods on infant brain tissue segmentation.
Women also reported more problems related to cocaine use and significantly more prior treatment episodes.
Adherence of molten zinc on the surface of high strength steel sheet improved significantly by prior Ni coating.
