Stereotactic accuracy and frame mounting: A phantom study

Abstract

Background: Frame mounting is considered one of the most critical steps in stereotactic neurosurgery. In routine clinical practice, the aim is to mount the frame as symmetrical as possible, parallel to Reid’s line. However, sometimes, the frame is mounted asymmetrically often due to patient-related reasons. Methods: In this study, we addressed the question whether an asymmetrically mounted frame influences the accuracy of stereotactic electrode implantation. A Citrullus lanatus was used for this study. After a magnetic resonance imaging scan, symmetric and asymmetric mounting of the frame, which could occur in clinical scenarios, was performed with computed tomography (CT). Three different stereotactic software packages were used to analyze the results. In addition, manual calculations were performed by two different observers. Results: Our results show that an asymmetrically mounted frame (deviated, tilted, or rotated) does not affect the accuracy in the mediolateral axis (X-coordinate) or the anteroposterior axis (Y-coordinate). However, it can lead to a clinically relevant error in the superoinferior axis (Z-coordinate). This error was largest with manual calculations. Conclusion: These results suggest that asymmetrical frame mounting can lead to stereotactic inaccuracy in the superoinferior axis (Z coordinate).

Accuracy of Robotic and Frame-Based Stereotactic Neurosurgery in a Phantom Model

“…It is therefore difficult to determine whether we are looking at a systemic error in the experimental setup or not, an explanation is yet to be found. Previous studies have addressed inaccuracies in frame-based stereotactic procedures due to asymmetrical mounting or distortions of the stereotactic device (Treuer et al, 2004 ; Alptekin et al, 2019 ; Renier and Massager, 2019 ). In the present phantom study, only the manual attachment of the stereotactic arc and the trajectory adjustment differed from the robotic procedure, not the positioning of the frame.…”

Effectiveness and reliability of hypnosis in stereotaxy: a randomized study

“…When it comes to awake procedures, the patient is able to sit up with the head straight, ensuring speedy and accurate mounting of the device. While the mounting may be reported to be painful and uncomfortable, it has to be carried out with special attention as the SF must be positioned as symmetrical as possible and parallel to Reid’s baseline [ 3 ]. In the case of awake DBS, pain and discomfort may be experienced by patients suffering from Parkinson’s disease (PD) during SF fixation as well as during scalp incision and may compromise their adherence to the procedure.…”

Early Deformation of Deep Brain Stimulation Electrodes Following Surgical Implantation: Intracranial, Brain, and Electrode Mechanics

“…Some authors focus on the difference between the intended-totarget point and the observed location of the contacts and calculate an "error of targeting" (Li et al, 2016), yet doing so they skip the deformation of the electrode and hide the different causes of the mismatch. However, although reductive, it emphasizes the notion of surgical inaccuracy, which is true for several reasons: (1) current stereotactic frames (surgical instrument for the implantation of the electrodes) and robotized systems have an intrinsic mean geometrical error usually of 1 mm (von Langsdorff et al, 2015;Alptekin et al, 2019); (2) manual measurements on X-ray films and surgical software introduce errors or inaccuracy, such as the difficulties of reading stereotactic rules (visual interpolation) and contact position on X-rays; (3) manipulation of surgical tools introduces limitations to the leaving and securing of electrodes in place (Contarino et al, 2013), with a global (2 + 3) precision roughly estimated, at around 1 mm; (4) erroneous targeting should be exceptional (pure error of targeting); and (5) mechanical issues can be encountered during the progression of the electrode, such as friction at the dura aperture, deviation by a foreign body along the tract such as surgical wax used for bone hemostasis, presence of significant blood vessels and arachnoid adherences, and changing of medium from tissue to ventricle and conversely. This notion of surgical inaccuracy should be separate from the delayed lead migration explained by mechanical issues such as technical error, repetitive dystonic head movement, and Twiddler's syndrome and reported between two CT scans separated by a mean interval of 1 year (differences of tip position or length of electrode > 3 mm) (Morishita et al, 2017).…”