Rotatie-osteotomie van het acetabulum met een robotarm

Robotic-assisted acetabular rotational osteotomy for better patient results

The Shanghai Electric Group Corporation Central Research Institute and Shanghai Sixth People's Hospital have teamed together to create SpheriObot, the world's first robotic system that uses an LBR Med for rotational osteotomy. Its theory and algorithm, control and implementation can be applied to all osteotomies required by orthopedic surgeons, such as orthopedic osteotomy due to deformity or high osteotomy due to degenerative changes in the femur and tibia.

Congenital hip dysplasia is a condition that causes pain, difficulty walking, severe deformity and even disability in children, adolescents and adults. More and more, physicians are leaning towards hip preservation surgery over artificial joint replacement, because the latter often leaves the patient open to multiple artificial joint revisions for the rest of his or her life. A common clinical procedure for hip preservation is periacetabular osteotomy, invented by Dr. Reinhold Ganz in Switzerland, which involves a multilateral osteotomy around the acetabulum to separate it from the surrounding pelvis. Symptoms are improved by adjusting the angle of the acetabulum to increase femoral head coverage.

There are, however, several risks that come with utilizing Dr. Ganz’s method:

First: the bone fragments cannot be easily realigned and may result in pelvic instability; second: due to the large amount of incision exposure, it may lead to delayed healing and even cause severe acetabular dislocation and acetabular necrosis; third: the osteotomy surface is very close to the blood vessels and sciatic nerve, and improper operation may lead to amputation of blood vessels and nerves; last: there are many complications associated with it, such as postoperative bone non-healing and loss of deformity correction.

A new, robot-assisted approach to periacetabular osteotomy

Due to the high surgical difficulty and risk of Ganz’s osteotomy, it can only be performed by experienced surgeons in some orthopaedic hospitals in China. In order to solve the many shortcomings of periacetabular osteotomy (Ganz osteotomy) in clinical surgery, the research and development team of the Shanghai Electric Group Corporation Central Research Institute and Shanghai Sixth People's Hospital designed a new type of acetabular rotational osteotomy robot (SpheriObot). SpheriObot robot consists of three parts: "Spheri", "O" and "bot," representing sphere, osteotomy and robot respectively.

Projectteam voor SpheriObot — Project Team for SpheriObot

This surgical robotic system uses the KUKA LBR Med robot as the main component, a special spherical pendulum saw and optical navigation positioning technology to completely disconnect the acetabular cup in a spherical shape. The acetabulum, with its cartilaginous surface, can be freely moved into a suitable match position with the femoral head. The entire osteotomy process can be thought of as "digging an ice cream ball". The process takes place far away from important neurovascular elements, making it minimally invasive, safe and less susceptible to sequelae, for a quicker recovery.

Speciale sferische pendelzaag — Special spherical pendulum saw

Shanghai Sixth People's Hospital introduced the 3D CT image reconstruction technology based on the development of the rotational osteotomy robot for the acetabular. Through the 3D bone reconstruction technology, the SpheriObot robot can find the osteotomy centre of the acetabular sphere and the ideal working boundary. The NDI camera with high positioning accuracy is used as the technical navigation of the system, and the upper computer system controls the working trajectory of the robot. Finally, spherical osteotomy on the acetabular fossa can be achieved with a minimum thickness of only 5 mm.

LBR Med sensors provide surgeon the perfect robot-guided assistant throughout the periacetabular osteotomy process

The LBR Med is equipped with torque sensors in each axis, giving the surgeon a smooth feeling when pulling the robot. Furthermore, it is perfect for monitoring the tangential and normal forces on the pendulum saw during the osteotomy process. So, the entire process of osteotomy can be visualized for the surgeon.
The robotic system SpheriObot uses the high repetition and positioning accuracy, NDI tracking system and 3D CT impact reconstruction technology. This allows intervention to be performed very accurately with a maximum deviation of 1° rotation accuracy and a positioning accuracy of less than 1 mm.

Acetabulaire, roterende osteotomierobot — Acetabular rotational osteotomy robot

Looking towards the future with robotic-assisted acetabular rotational osteotomy

Shanghai Sixth People's Hospital has produced the first prototype of a spherical osteotomy device in China. They will rely on and be supported by the R&D, production and marketing resources of Shanghai Electric Group to improve and refine the system, pass various tests in the industry and finally enter the market.
They hope that their products will be promoted all over the world for the benefit of the world's people and become a good helper for doctors.