Minimally invasive tubular retraction and transtubular approaches in neurosurgery

Abstract

Minimally invasive surgical approaches have revolutionized surgical care and are becoming increasingly common and sought after in neurosurgery. Despite significant advancements in these techniques and associated technologies, the use of spatulas, that remain essentially unchanged since the late 1800s, for brain retraction endures as a mainstay of neurosurgical practice. In the last decade, tubular retractors have been successfully used in the management of deep-seated intraparenchymal and intraventricular lesions but have yet to be used to minimize brain retraction in skull base surgery. In order to determine the full applicability of transtubular techniques in neurosurgery, we compare brain retraction pressures between tubular retractors and brain spatulas in common neurosurgical approaches, assess the feasibility of performing minimally invasive transtubular skull base and general neurosurgical approaches, and introduce a novel technique for closure of transtubular minicraniectomies with maintenance of anatomic integrity. In all approaches assessed, tubular retraction resulted in average brain retraction pressures that were 57% less collectively than those resulting from spatula retraction. Tubular retractors demonstrated more consistent average retraction pressures between approaches and required 50% less mean retraction distance compared to spatula retractors, while cortical tearing was observed microscopically in 39% of cases following spatula retraction. Transtubular supraorbital, anterior transpetrosal, interhemispheric transcallosal, retrosigmoid, and supracerebellar infratentorial approaches are safe and effective surgical corridors to their respective intracranial targets, with ample surgical exposure, freedom, and maneuverability and minimal retraction of brain tissue. The tubular retractor provided sufficient working space for standard bimanual surgical technique without obstruction of the visual field and permitted sufficient surgical freedom while allowing for constant monitoring of retracted tissues. Adequate preoperative planning of the surgical trajectory was critical for facilitating a safe, direct, and practicable surgical corridor. Closure of transtubular minicraniectomies could be accomplished by rapid on-demand 3D printing of patient-specific cranioprostheses which was found to be a novel, feasible, and inexpensive option that was accomplished with minimal technical difficulty. Tubular retraction in neurosurgery provides a safe and effective conduit for the application of percutaneous minimally invasive approaches while inducing substantially reduced brain retraction pressures than conventional spatula retractors. Advances in neuronavigation and surgical robotics will continue to expand the indications for tubular retraction in neurosurgery.