Case Study

Developments in Robotic Surgery and Types of Machines
Robot-Assisted Spine Surgery and Innovations
Force and Tactile Sensing for Robotic MIS
Merits, Demerits and Future of Robotics
Case Study

Post-Operative CT Analysis of Spine Surgery with Miniature Robotic Guidance

Accurate and precise placement of pedicle screws is important yet challenging. Misplaced screws may result in neural and vascular injury, with short- and long-term sequelae. A prospective, multi-center clinical case series analysis was done to examine clinical accuracy and efficacy of bone-mounted robotic guidance for spine surgery, based on post-operative CT analysis.


Twenty eight patients with age ranging from 33 to 77 years (average age = 54). Indications for surgery included spinal instability, spondylolysis, spondylolisthesis, degenerative and inflammatory disc disease, joint disease and adjacent level disease.

Six of the patients were obese (class I, II and III), and four were revision cases. Surgical procedures included single level to three levels (T12 –S1) TLIF, PLIF and posterior fusion cases, including open and minimally-invasive techniques. Pedicle screws were introduced using miniature robotic guidance in all cases. The system utilized a pre-operative CT scan for optimal planning of screw size and position, two fluoroscopic images (AP and Oblique) for automatic registration to the CT data, and a rigid frame - attached to the bony anatomy percutaneouslyor via a small midline incision – as a basis for the miniature robotic device.

The device then guides the introduction of instrumentation to entry points and trajectories in accordance with the pre-operative plan. Post-operative CT scans were obtained for all patients and screw placements were evaluated and divided into 4 categories (see figure below):

A–completely within the pedicle, B-pedicle wall breach less than 2 mm, C-pedicle wall breach 2–4 mm, D-pedicle wall breach greater than 4 mm

Each screw was evaluated in the axial and lateral views independently.


A total of 113 screws were implanted using the robotic system. 3 screws could not be evaluated due to poor post-operative CT quality. 108 (98.2%) of the 110 evaluated screws were in groups A+B (96+12, respectively). 2 screws (1.8%) were in group C and no screws were in group D; hence all of the screws (100%) were within the safe zone for pedicle screws. There were no clinical sequelae; none of the screws had to be revised.


Miniature Bone-mounted robotic guidance technology yielded accurate, safe and reproducible placements. These results compare very favorably with reported accuracy in the literature. The technology is useful, reliable and beneficial for spine surgery.