High arched palate - will it influence orthognathic surgery result?

Probably: A high arch is often associated with mouth breathing and/or sinus issues. The orthognathic surgery may collapse if the underlying problem is not corrected first. Palaltal expansion prior to surgery may increase the success of surgery.

Not necessarily: Your oral surgeon will take this in to account while planning your surgery.

Not usually.: The high arched palate is taken into account during the planning phase of orthognathic surgery. If it is early in the orthodontic and surgery planning, the palate can be expanded with appliances or even a primary surgery to widen the palate. If not then the upper jaw (maxillary) may require sectioning in a few pieces to widen it and correct any width discrepencies.