ZAP-X Gyroscopic Radiosurgery System: A Preliminary Analysis of Clinical Applications within a Retrospective Case Series

Authors

Benjamin K. Hendricks, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.Follow
Joseph D. DiDomenico, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
Igor J. Barani, Department of Radiation Oncology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
F David Barranco, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.Follow

Document Type

Article

Abstract

INTRODUCTION: The ZAP-X Gyroscopic Radiosurgery system (ZAP Surgical Systems, Inc., San Carlos, CA, USA) is a novel high-dose targeted stereotactic radiosurgery platform for outpatient use that includes self-shielding, X-ray image guidance, and the capacity to aim the radiation beam gyroscopically at an intracranial lesion using 5 independent degrees of freedom. The ZAP-X Gyroscopic Radiosurgery system accomplishes these actions while meeting widely accepted standards for dose gradient and accuracy. This retrospective study examined data of patients treated with gyroscopic radiosurgery (GRS) to document clinical outcomes. METHODS: Medical records of all outpatients treated with GRS over a 20-month period from January 2019 to August 2020 were searched to extract relevant details, including follow-up data until August 2021 (32-month study interval). Patients with <6 months of radiographical follow-up data were excluded unless death occurred. Data collection included pretreatment clinical history, pathological diagnosis, radiographical features, treatment parameters, and long-term clinical and radiographical follow-up. RESULTS: Sixty-eight patients received outpatient treatment with GRS during the 20-month treatment interval, with 59 patients remaining after exclusion for the minimum follow-up threshold, with a mean (standard deviation [SD]) fractionation of 1.85 (1.63). Eighty-two lesions were treated across a very heterogeneous patient population, including meningiomas (42.4%), metastases (39.0%), gliomas (6.8%), schwannomas (1.7%), and pituitary tumor (1.7%). Mean (SD) radiographical follow-up data (14.7 [6.60] months) were available for 56 patients. During that interval, 13 treated lesions in 13 patients (15.9%) demonstrated progression, 9 of which were stable during the initial posttreatment imaging surveillance period. Mean lesion volume was stable from pretreatment (2.54 cm3 [4.37 cm3]) to most recent follow-up (2.80 cm3 [8.20 cm3]) (t [79] = -0.310; p = 0.76). Minor adverse clinical events were noted in 3 (5.1%) of the 59 patients during the posttreatment phase that may have been related to the treatment. Ten (16.9%) patients died within the 32-month study interval. DISCUSSION/CONCLUSION: This preliminary assessment of the first series of patients treated with the Zap-X Gyroscopic Radiosurgery system documents its overall feasibility in clinical applications. Although the duration of follow-up was brief, GRS appeared to be both safe and effective. Additional analysis, with an ongoing prospective registry, is underway.

Medical Subject Headings

Follow-Up Studies; Humans; Meningeal Neoplasms (surgery); Meningioma (surgery); Radiosurgery (methods); Retrospective Studies; Treatment Outcome

Publication Date

1-1-2022

Publication Title

Stereotactic and functional neurosurgery

E-ISSN

1423-0372

Volume

100

Issue

2

First Page

99

Last Page

107

PubMed ID

34942629

Digital Object Identifier (DOI)

10.1159/000519862

Recommended Citation

Hendricks, Benjamin K.; DiDomenico, Joseph D.; Barani, Igor J.; and Barranco, F David, "ZAP-X Gyroscopic Radiosurgery System: A Preliminary Analysis of Clinical Applications within a Retrospective Case Series" (2022). Neurosurgery. 1765.
https://scholar.barrowneuro.org/neurosurgery/1765