Very interesting meta analysis. And a bit surprising that there is no significant difference between intraoral and cervical approach.
And surprising that there isn’t Eagle jugular syndrome mentioned, or have I overlooked that? Maybe it was a bit too early when the analysis was done in 2018. So the very recent literature wasn’t available.
" Complete resolution of pain showed no association with styloid process length, morphology, angulation or degree of resection; if, however, resolution is incomplete, it should be checked whether resection was sufficient , given that Steinmann  demonstrated that the styloid process may regrow years after styloidectomy, which is attributed to embryonic cartilage residue."
Thank you for the article summary @TheDude! We tend to work under the assumption that the styloid necessarily needs to be removed to the greatest extent possible for the best recovery from ES symptoms, but this article shows evidence that’s not always the case. I believe we also have some members on our forum who recovered well from symptoms when only a portion of their styloids were removed. Unfortunately, it seems the majority need the SP shortened significantly, but the determining factors are likely the physical features of the styloid which are causing the symptoms i.e. length, angle, thickness, etc.