Resection of Thoracic Intramedullary Breast Metastasis Through the Dorsal Root Entry Zone: 2-Dimensional Operative Video

Abstract

Intramedullary spinal cord metastases (ISCMs) are rare, representing 8.5% of central nervous system metastases and 5% of intramedullary lesions.1 With the advent of immunotherapy leading to longer-term survival for cancer patients, intramedullary metastases are on the rise.2 A 43-year-old female presented with acute right leg weakness and sensory loss (Video 1). Magnetic resonance imaging revealed an avidly enhancing mass in the spinal cord at T6 with associated edema. Surgical resection was performed for tumor debulking to stabilize and ideally improve neurologic function, as well as for tissue acquisition for molecular profiling and targeted therapy. ISCMs are typically entered via midline myelotomy after a standard posterior exposure.3 However, on dural opening and visualization of the spinal cord, it was apparent that the tumor involved the right T6 nerve root. The decision was then made to enter the lesion via the T6 dorsal root entry zone (DREZ).4 Microsurgical resection of the tumor was performed with the aid of ultrasound and D-wave motor monitoring. Postoperative magnetic resonance imaging showed gross total resection and the patient was discharged to acute rehabilitation with increased right leg weakness and stable sensation. We demonstrate that for ISCM involving the exiting nerve root, DREZ myelotomy is a viable alternative to midline myelotomy. We strongly recommend use of D-wave monitoring in such cases as it clearly impacted our ability to maximize the resection. This is the first video where the DREZ approach is emphasized along with utilization of D-wave monitoring. The patient consented to the surgical procedure and the use of intraoperative video for education purposes.