Intraoperative / Surgical CT

Mobile cone-beam CT designed for operating-room use. Brings volumetric CT imaging into surgery for real-time pedicle-screw placement verification, ENT + skull-base surgery, orthopedic trauma, cardiothoracic, and increasingly cardiac-surgery workflows. Integrates with surgical navigation platforms (StealthStation, Brainlab).

Why it exists

Spine surgery pedicle-screw placement accuracy was the pre-O-arm challenge. Misplaced screws require re-operation + risk neurologic injury. Intraoperative CBCT allows the surgeon to verify screw position before closing — eliminating reoperation rates dropped significantly in spine centers that adopted it.

Form factor

Medtronic's O-arm (O2) is the category-defining example:

• Appears as a mobile C-arm with an opening C-shape for positioning
• Articulates to close into a full O-shape (full ring) for the CBCT scan
• Rolls in + out of the OR between surgical steps
• Patient stays on the OR table (no transfer to CT)

Clinical workflow

1. Patient positioned + draped on OR table; O-arm wheeled in.
2. O-arm opened for positioning (mimics a C-arm).
3. Articulates closed into the O-ring configuration for CBCT acquisition.
4. CBCT reconstructed + registered to preoperative imaging in StealthStation.
5. Surgeon places pedicle screws with navigated instruments, tracked against the CBCT.
6. Confirmation CBCT before closure verifies screw position.

Key specs

• Bore — ~96 cm (fits the OR-table patient)
• CBCT — rotating kV flat-panel system
• Navigation integration — StealthStation, Brainlab (vendor-dependent)
• Mobile — wheels in + out
• Dose — per-scan dose lower than medical CT (smaller volume, lower kVp + mA)

Clinical use

• Spine surgery — primary indication. Pedicle-screw verification + trajectory planning.
• ENT / skull base — sinus surgery, cochlear implants, skull base tumor resection
• Cardiothoracic — endobronchial tumor ablation, aortic endografts
• Orthopedic trauma — complex fractures

Systems

• Medtronic O-arm (O2)
• Ziehm Vision RFD 3D (alternative mobile CBCT + nav-ready)
• Brainlab Loop-X (Loop-shape mobile CBCT)
• Philips Allura Xper + surgery-suite configurations (fixed; not strictly mobile)

Regulatory

• State radiation registration (same as any CT)
• Physicist survey
• OR use falls under same state radiography regulation as fixed CT rooms
• Operator training (surgeons + rad tech for scan operation)

Related

• Mobile C-arm (predecessor workflow)
• Medical CT (technology parent)
• O-arm
• Medtronic