HISTORICAL ASPECTS AND DEVELOPMENT OF ROBOTICS IN ORTHOPAEDIC SURGERY

Abstract

Robotic technology in adult reconstruction – initially the placement of the stem during THR – was introduced in the early nineties of last century, starting in the US. The underlying technology dated back to the year 1986. Because of regulatory restrictions the technology could not spread in the US, but was exported to Europe in 1994. There the technology – primarily distributed in Germany – had a great success and by the year 2000 roughly 50 centers were using Robodoc – the first robot on the market – and a very similar German competitor’s product, CASPAR.

The initial robot was a crude machine, basically the unchanged beta version. Cumbersome fixation, a registration process using three fiducials, the requirement for second surgery to place the fiducials, and last but not least raw and hardly elaborated cutting files made surgery with Robodoc a demanding undertaking. Yet feedback from the surgeons, sometimes vigorously expressed during regular user meetings, let to continuous evolution of the system and resulted in an advanced and stable technology. Also training – with important input from the already experienced sites – improved significantly, which can best be demonstrated by procedure time for first surgery: in Frankfurt 1994 roughly four hours, while today first surgeries at new sites rarely exceed two hours. Further applications – revision surgery, total knee replacement – helped to justify the significant investment into the system.

While robotic technology underwent evolution, other related technologies were developed and entered the market. Main products were the navigation systems, which initially were developed for neurosurgery and spine surgery and which, due to easier handling and lower costs, found more acceptance on behalf of the surgeons. Although the navigation technology in some regards is a step back from the robotic technology, it appealed for just that reason: the surgeon stays in the loop. The surgeon uses the traditional instruments, and the navigator helps him to achieve precision in reaming or placement of implants. In orthopaedic surgery navigators became very popular in TKR, but also in THR.

Another development, completely unrelated to the mentioned technology, presented a new challenge: minimal invasive surgery. While in knee surgery the introduction of arthroscopy in the late seventies already proved the feasibility of minimal invasive techniques, adult reconstruction remained the domain of sometimes aggressive and robust surgery. Only recently minimal invasive procedures were introduced and standardized for a couple of applications. It is important to stress the fact that the term ‘minimal invasive’ did not relate to the size of skin incision only, but to the overall degree of soft tissue damage necessary to prepare for and place the implants. Some companies now offer new instruments allowing for very minimal incisions and reduced soft tissue compromise. In contrast to this development robot assisted surgery remained – in spite of numerous improvements – a rather invasive piece of surgery. These separate developments – navigators and minimal invasive surgery – made robot assisted joint surgery in the eyes of many potential users a rather outdated, superfluous and expensive type of technology. It is therefore time to revisit the original intentions that let to the development of robot assisted surgery.

The original ideas were sponsored by veterinary surgeons specializing in cementless THR for dogs. They experimented with custom implants, but they identified two fields of concerns: fractures and poor placement. Both problems are – still – common in human THR. Robot-assisted surgery was supposed to mainly address these problems. Another asset of robot-assisted surgery is seen in machine milling, which was invented as part of the robotic procedure and which turned out to be superior to conventional reaming.

The published results of robot-assisted THR (i.e. Nishihara et al, 2006) prove that these requirements were met. In our own series in Spain we had no fracture and every single implant was seated according to the preoperative plan. Animal experiments allowing for histological examination of the bone-implant interface showed the uncompromised cancellous scaffolding supporting the implant, while hand-reamed interfaces showed signs of destruction and atrophy.

On the other hands there are concerns that current minimal invasive approaches do cause problems in these regards: control of position is mainly feasible by use of intraoperative x-ray, and fractures do occur.

Therefore robot-assisted surgery seems to be the ideal complement for the minimal invasive approach. The deficits of MIS regarding orientation and visualization of the surgical object can be compensated by the robots proven ability to execute preoperative established plans. The challenge is the current invasiveness of robotic surgery, which – as primary tests and studies show – can be easily accounted for.

In conclusion there is an ever increasing role for robot-assisted surgery in adult reconstruction. It is up to the surgeons to define the requirements and ask for specifications that will meet their and the patient’s expectations regarding the degree of invasiveness involved.