A pineal parenchymal tumor of intermediate differentiation (PPID) is a rare entity, and optimal treatment is still unclear. Combined multimodality treatment should be considered in PPID due to high recurrence rates. Gross total resection is the first choice of treatment, however, it may not be feasible in every case due to location. Stereotactic radiosurgery (SRS) can be considered for the treatment of primary and recurrent disease, as it enables us to deliver a high radiation dose to the target while minimizing radiation exposure to normal tissue. In this report, we present a case treated with hypofractionated SRS for recurrent/metastatic PPID after the primary tumor was controlled with the combination of surgery and conventionally fractionated radiotherapy.

BACKGROUND: Electrode implantation for deep brain stimulation (DBS) can be performed in numerous ways, but the current \"gold standard\" is the use of frame-based systems for accuracy. Robotic stereotactic procedures, however, have gained increased interest because of their ease of use and reliability, but there could be concern about their safety in the United States as the result of recent lawsuits (e.g., the da Vinci Surgical System). We report the first DBS implantation performed using a robot (ROSA robotic device) approved by Food and Drug Administration for use in North America.
METHODS: A 56-year-old, right-handed woman with a 12-year history of Parkinson disease is described. She was offered bilateral subthalamic nucleus DBS placement to address motor fluctuations and dyskinesias. DBS electrode implantation was implemented successfully with ROSA robotic stereotactic assistance. Using preoperative magnetic resonance imaging scan acquisitions, we targeted the patient\'s subthalamic nucleus bilaterally. Bone fiducials were placed and intraoperative computed tomography (CT) imaging was obtained. The magnetic resonance imaging and CT were fused, and the patient was registered to the ROSA software. Trajectories were obtained and a microdrive device was fixed to the robotic arm to advance the electrode to the correct location. Electrodes were then placed bilaterally. Intraoperative CT showed good placement with no complications encountered.
CONCLUSIONS: The advantages of robotic assistance in stereotactic procedures are as follows: 1) improved accuracy, 2) \"arc-less\" approach, and 3) minor adjustments can be made in multiple planes to the entry point without adjustment of a frame. The case demonstrates robotic stereotactic assistance viability as an alternative to traditional frame-based or frameless systems in U.S. hospitals.