Smart Cavity Creator Drill for Lumbar Interbody Fusion: Direct to Phase II

Project Summary More than 500,000 lumbar fusion surgeries are performed each year in the United States, but new leg pain from iatrogenic nerve root injury remains a complication in 5% to 16% of patients. The interbody fusion portion of the surgery involves time-consuming and technically challenging steps of nerve root exposure and retraction, cau- terization of bleeding around the nerve root, dorsal root ganglion and epidural space, removal of disc material from vertebral end plates using manual knives, rongeurs, curettes and rasps, and then insertion of an interbody cage implant containing bone graft. Surgical dissection must be as large as the cage, which is usually 7 mm to 18 mm tall and twice as wide, and hence, longer operative time, more blood loss, and more frequent nerve root injury and dural tear are reported with interbody fusion even for current minimally invasive methods. A safer technique is needed. In this Direct to Phase II SBIR application, we propose to commercialize a novel lumbar interbody fusion technology that uses a very small approach channel to create a large cavity in the center of the disc space to allow bone growth and thus avoid risks associated with complex surgical dissection. This technique (“Smart Cavity Interbody Fusion” or “SCIF”) is based on strong proof-of-concept demonstrations of successfully integrating a cavity-creating drill with smart sensors to substitute for manual instruments and direct visualization. We have shown that this sensor-enabled, articulated drill bit (“Smart Cavity Creator” or “SCC”) can reproducibly create precise cylindrical cavities ranging from 4 mm to 16 mm in diameter within the disc space through a small access shaft of only 3.2 mm diameter. Further, that a drill guide can be locked rigidly to lumbar spine pedicle screws to define pre-specified drill trajectory and cylindrical cavity dimensions, and that sensors integrated into the drill bit can trigger automatic shut-off when changes are detected during transitions, for example, from disc material to vertebral body cortical end plate bone and then vertebral body cancellous bone. Sensors enhance procedural safety and speed compared to current manual methods. Our aims are (1) to simplify the drill guide, (2) to conduct in vitro validation of SCIF to the currently most common interbody fusion technique as the gold standard: Transforaminal Lumbar Interbody Fusion (TLIF), and (3) to conduct in vivo validation of SCIF vs. TLIF for fusion success, safety outcomes, efficiency, and usability in 20 live pig experiments with survival to 3-months. Validation will achieve “Design Freeze” of the technology. We have requested a pre-submission meeting with the FDA and will prepare Quality Management System (QMS) for regulatory submission. A major medical tech- nology company, Globus Medical, is interested in acquiring the technology if the proposed validation studies are successful.