The decision to select a specific incision would depend on the several aspects e.g. surgical site, related anatomical structures, easy access, fewer complications, quicker healing and minimum scar. But, at instances, all these options might not be fulfilled and the surgeons have to make a professional judgment as to decide on what's best for the patients' condition.
The marking of the skin incision is done, so that its two endings form an imaginary straight line that adequately simulate the separation of the skin flap and the consequent bone exposure
Bicoronal skin incision for bifrontal craniotomy.
The entrainment of air typically occurs during bone work, but Spence et al. describe a case in which a venous air embolism (VAE) was recognized while working on the scalp. Monitoring techniques are critical for early treatment of VAE to avoid more serious complications, and our case illustrates the need to implement monitors early and remain vigilant throughout the procedure 1).