Patient positioning for retromastoid craniotomy is very important since the shoulder has to be moved out of the working zone of the surgeon. And more importantly, the patient should be placed in the most physiological position to avoid any blockage in cranial venous drainage or strain on the neck of the patient. I have come to a like their lateral position for retromastoid craniotomy, and have abandoned the use of supine position even for patients who are relatively thin. In this patient as you can see, tape has been placed over the shoulder of the patient and the patient has been gently retracted anteriorly and caudally. Let's go ahead and review the nuance of technique for placement and planning of the curvilinear incision. I have also abandoned the use of the linear incision for retromastoid craniotomies. I use the curvilinear incision as you can see here, the landmarks to plan this incision are as follows. First the inion is identified here and the root of zygoma is identified there. I plan a dashed line as you can see here. And also I plan a hash line as you can see here, just over the mastoid groove. Where these two lines join is essentially the approximate location of the transfer sigmoid junction. That is the summit of my curvilinear incision. Once the summit of the incision has been found, one leg of the incision is planned and the other leg is more linear to be away from the ear as much as possible. Here is again the marking for location of the mastoid tip here, and a mastoid groove here. You can again appreciate the head of the patient has been turned slightly toward the floor to facilitate movement around the cerebellopontine angle cistern during the earlier stages of intradural work.
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