"since initial" is a correct and usable phrase in written English.
It can be used to refer to something that occurred at the beginning or start of a process or situation. Example: Since initial implementation, the new software has greatly improved our efficiency.
Furthermore, this paper specifies the role of science for initiating a positive interaction with technological development, since initial stages of development and during catching up processes.
We therefore focused on examining initiation of high-risk oral NSAID prescriptions, since initial analysis showed that clinician identifiers were reliably recorded in this context.
Fine Gael and the British Conservatives have developed close ties since initial meetings between Kenny and David Cameron in 2007.
Update: I've interviewed Wenig since initial publication and have updated this story with his comments.
Since initial introduction in the early 1970s, airbags have gone under numerous revisions and improvements to safety.
Since initial conceptualizations, schizophrenia has been thought to involve core disturbances in the ability to form complex, integrated ideas.
Ecosystem behavior can be studied since initial state conditions can be precisely specified and tracked over different ranges of time.
Since initial visit is under the patient's influence the hospital dummy represents the choice hospital by the patient.
Since initial acquisition is performed prior to calculating the weight vector, an algorithm to enlarge the acquisition coverage is required.
Results: Most patients were women (61%), white (95%), married (65%), and had a mean interval since initial DVT of 16 months.
Since initial methods were developed for isolating cells from adipose tissue, little has been done to improve mesenchymal stromal cell (MSC) yield.
