3D laparoscopy – a bridge between conventional surgery and robotics

Introduction

3D surgery has significant advantages. High-resolution images even  make the smallest tissue structures visible and enable better spatial perception – an important aspect in the training of junior surgeons. In addition, modern “wireless” systems facilitate ergonomics during surgery – and the purchase and material costs of the 3D laparoscopy are also lower when compared to robotics.

Laparoscopic surgery has a long tradition in Germany. The first laparoscopic appendectomy was performed in 1980 by the gynaecologist Professor Dr. Kurt Semm at Kiel University Women’s Health Clinic. Five years later, the first laparoscopic gallbladder resection worldwide was performed by the surgeon Professor Dr. Erich Mühe at Böblingen District Hospital. Even then, Professor Mühe was impressed by the fast recovery of his patients after the laparoscopic surgery. He further developed the laparoscopic cholecystectomy technique and refined the surgical instruments. He presented his results at the German Surgeons’ Congress in Munich a year after his first successful cholecystectomy. At that time, Professor Mühe had already performed 97 laparoscopic cholecystectomies. However, his new surgical procedure met with rejection among his colleagues. The minimally invasive surgical procedure was considered to be too dangerous. This is hard to imagine from today's perspective, a good 30 years later. Nowadays, laparoscopic cholecystectomy has become established as the standard procedure for gallbladder resections, without ever having conducted a comparative randomised prospective study on the superiority of laparoscopic cholecystectomy vis-à-vis conventional cholecystectomy. The advantages of laparoscopic surgery are evident: faster recovery times as a result of reduced trauma in the abdominal wall, less pain, faster mobilisation, fewer abdominal adhesions, shorter hospital stays and treatment durations. The methodology of laparoscopic surgery has been further developed and refined over the years so that laparoscopic surgery can now be performed on all abdominal organs. Video transmission on a monitor, the differentiation between surgical instruments and the development of “seal and cut” instruments for hemostatis and to a great extent for atraumatic tissue separation have enabled significant progress.

Millimetre-precision control

A surgical robot was developed in the 1980s in order to be able to perform remote surgery in trouble spots. This consists of a control panel at which the surgeon sits and a robot unit, which is located in the operating theatre with the patient. The surgeon gets an image of the surgical area via the 3D camera, which is inserted into the patient by means of the robotic arms, and can operate the other robotic arm remotely. The robotic arms, which are equipped with microsurgical instruments, have several rotary axes so that the instruments can be controlled with millimetre precision in confined spaces. The da Vinci robotic system was approved from the turn of the century and is increasingly found in clinical use. A major advantage of the robotic system is that the normal levels of freedom in a human hand can also be transmitted in confined spaces with the help of the robotic arms controlled in real time. The computer system of the robot is even able to suppress involuntary hand movements, such as hand tremors. Small structures, such as nerves or small blood vessels, are illustrated clearly by the 3D camera image, which can also be enlarged if necessary. The main disadvantage of the robotic system is the immensely high purchase costs and the high cost of microsurgical instruments, which need to be replaced after ten procedures.

High-resolution 3D images and better ergonomics

The miniaturisation of 3D camera technology was also able to revolutionise laparoscopic surgery. Two camera chips are located at the tip of the distal tip of the endoscope together with the glass fibre light guide. The 3D image is transmitted to the surgical monitor. The surgeon can use 3D glasses to see a high-resolution three-dimensional image of the surgical site. As with the robotic system, the image can be enlarged multiple times to illustrate fine structures in different ways. The three-dimensional image can be transmitted to another monitor so that the surgeon and the surgical assistants also have a monitor in their line of sight. This significantly improves the ergonomics for surgeons. In the early days of laparoscopic surgery, the advantages of minimally invasive surgery were primarily considered to be the reduced surgical trauma for patients. Very little attention was paid to the needs of the surgical team. The surgeons frequently suffered from neck, shoulder and back pain because of excessively small monitors, difficult to operate instruments and unusual postures during the surgery. Due to the immense further developments in laparoscopy within the last three decades, there have been significant ergonomic advances in surgical instruments and a considerable improvement in the visualisation of the surgical site. This has led to noticeably improved working conditions for surgeons.

Three-dimensional spatial perception as a crucial learning advantage

The training concept for junior surgical staff had to be reconsidered and revised with the widespread introduction of laparoscopic surgery. The training for laparoscopic surgery takes place in training centres. The individual standardised surgical steps are practised and performed on synthetic or animal organs. The difficulties in classic laparoscopic surgery are the significantly lower tactile sensation compared to conventional surgery and the significantly reduced spatial perception through the two-dimensional image generated on the surgical monitor. Within the scope of a doctorate, we extensively analysed the manual learning of minimally invasive surgical techniques on untrained medical students at the surgical training centre in Konstanz. The students were divided into two groups. One group learned the minimally invasive techniques exclusively through the two-dimensional images conveyed to the surgical monitor by the camera; the other group learned the same techniques both on a two-dimensional monitor display and through a three-dimensional view of the surgical site. This showed quite clearly that three-dimensional spatial perception is a crucial learning advantage for learning complex surgical tasks. This might not come as a surprise on the face of it because it reflects our experience in daily life. However, spatial perception takes a little getting used to on a two-dimensional monitor for minimally invasive surgery and requires intensive training, especially when complex surgical measures, such as intercorporeal suturing and knot tying needs to be performed in confined spaces.

“Wireless” operating theatres

We have been working with the EinsteinVision® 2.0 3D laparoscopy system at Konstanz Hospital since April 2016. It is used on an interdisciplinary basis in thoracic surgery, gynaecology and visceral surgery. In visceral surgery it is used routinely for all complex operations, such as oesophagus, stomach, pancreas, liver, colon and rectal surgery. The system offers excellent image quality on two surgical monitors, which can be switched alternately between 2D or 3D. The wireless connection of the additional monitor enables it to be positioned “wirelessly” in the operating theatre to suit the needs of the surgeons. The camera with the appropriate endoscope has a sterile cover so the endoscope does not need to be sterilised. This means that multiple operations can be performed in succession with just one endoscope. The EinsteinVision® system has a short familiarisation phase. The three-dimensional view during laparoscopic surgery is often much better than during conventional surgery, especially when operating in confined spaces. The camera with the integrated light fibres has a diameter of ten millimetres and can also be well positioned in confined spaces, in which it is hard to achieve an adequate level of illumination during conventional surgery – let alone an adequate view for the surgeon and their assistants. The surgeon and their assistants always have an identical view of the surgical site in laparoscopy. Complex surgical steps, such as a lymphadenectomy in the hepatic hilum or intracorporeal suturing of anastomoses can be performed safely with a three-dimensional view, in the same way as in conventional open surgery, thanks to the accurate spatial perception.

Conventional surgery is the basis of the surgery and can be learned in the classic way by an assistant during an operation. The tactile sensation is excellent because of the surgeon's “instinctive feeling” and the levels of freedom are defined by the mobility of a human hand. There must be an appropriate entry incision in order to achieve adequate exposure. This constitutes a fundamental part of the surgical trauma, resulting in longer recovery times with conventional surgery, whereas in robotics, the view of the surgical site is also ideal in confined spaces because of the state-of-the-art 3D visualisation. Even higher levels of freedom can be achieved than with a human hand thanks to the additional levels of freedom provided by the robotic arms. The surgical trauma in the abdominal wall is considerably lower than with conventional surgery. However, the main disadvantages of the robotic system are the lengthy training and the immense purchase and material costs. 3D laparoscopy provides a bridge between conventional surgery and robotics. The surgical site can be ideally depicted in 3D and enlarged by a 3D endoscope suitable for the robotics. In the past, the levels of freedom were often limited by the position of the trocar and the linear instruments. Additional levels of freedom can be achieved with the increasing number of articulable operations and sealing instruments coming onto the market, which will significantly improve the main shortcoming of minimally invasive surgery. The purchase and material costs for 3D laparoscopy are significantly lower than the costs for robotics so virtually all operations performed on internal organs are cost-effective.

Conclusion

3D laparoscopy represents an excellent minimally invasive surgical procedure. It is therefore used for all minimally invasive operations in thoracic surgery, gynaecology and visceral surgery with a higher degree of difficulty at Konstanz Hospital. Oesophagus, stomach, pancreas, adrenal, liver, colon and rectal surgery is performed with 3D laparoscopy in order to ensure cost-effective work procedures. In contrast, inguinal hernia surgery, cholecystectomies and appendectomies continue to be performed with the classic 2D camera, which can also alternatively be connected to the camera control unit of the EinsteinVision® visualisation system.