Fig. 5

Upper cervical and foramen magnum neurofibroma with intradural extension (female patient, 45 years old, hemilaminectomy); a preoperative MRI T1 with contrast, b intraoperative ultrasound images and c early postoperative MRI T1 with contrast; arrow 1; the part of the tumor inside the spinal canal (intradural), 2; the part of the tumor mostly outside the spinal canal, 3; bone artifact, 4; dura, 5; the odontoid, 6; the spinal cord, 7; the foramen magnum, 8; nerve root and 9; resection cavity