Incision reveals that the ridge is narrower than CT indicates.  Considering that the patient is nervous, one-staged ridge split starts with ridge top split with surgical fissure bur, followed by a 2-mm pilot drill 8.5 mm deep.  A calculated parallel pin is inserted for the 1st intraop PA (Fig.1 (red dashed line: the Inferior Alveolar Canal and Mental Foramen)).

1-Staged Ridge Split 劈开术 Next Xin Wei, DDS, PhD, MS 1st edition 01/27/2016, last revision 04/10/2021