Networked OR - A Strong Team
In the neurosurgical clinic at the University of Ulm, Germany in the Günzburg Regional Hospital, it’s not just the physicians and nursing staff who form a practiced unit. In 'BrainSUITE', one of Germany's first ORs with integrated magnetic resonance tomography and neuronavigation, partners Siemens, BrainLAB, Zeiss and Trumpf Medical are also showing team spirit: in the service of intraoperative diagnostics.
The door to OR no. 4 in the neurosurgery department of the regional hospital in Günzburg, Bavaria opens slowly. 'That's because of the HF insulation,' explains Josef Birzle, head of nursing care. He was also responsible for installation of the operating room behind this door, the so-called 'BrainSUITE', an OR with integrated magnetic resonance tomography (MRT). 'Each electromagnetic wave disturbs the imaging of the nuclear spin, so the shielding measures start right at the doors,' says Birzle. The name 'BrainSUITE' includes the precision interplay of a high-resonance MAGNETOM Espree MRT from Siemens Healthcare, a navigation and data management system by BrainLAB, a ceiling-mounted operation microscope by Zeiss, and the JUPITER OR table system by Trumpf Medical. Their common goal: to simplify lengthy and often complex brain surgery for surgeons, nursing staff and of course, for the patients themselves. Since the onset of planning for the new OR area, which started operation in December, 2007, the hospital had fond dreams of such an OR, says Birzle. Now, the dream is reality. Since September 2008, the Günzburg neurosurgeons, led by Medical Director Dr. Wirtz, have operated in the BrainSUITE. The medical project leads, Dr. Thomas Schmidt and Dr. Ralph König, report thoroughly positive experiences with respect to workflows, patient safety and surgical precision.
But back to the OR. Here, the safety aspect is in sharp focus. Coloured markings on the floor indicate the critical areas of the magnetic field to physicians and nursing staff. The 1.5 Tesla MRT is within the red 50-gauss line and the yellow 5-gauss line. Patients with e.g. pacemakers or other metallic foreign objects may not pass those lines. 'It wouldn't work anymore,' says Dr. Schmidt. 'We check for this specifically in a detailed case history questionnaire, and of course there is a clinical examination before the operation.' The instruments around the OR table are also located at a safe distance from the magnetic field. Working with an MRT in the OR may be a challenge – but it has its advantages: 'For instance, if cerebrospinal fluid escapes during brain surgery, the anatomy changes immediately. This is a so-called "brain shift",' explains Dr. Schmidt. 'And a nuclear spin made earlier is suddenly no longer current.' Furthermore, certain brain tumours can be distinguished from health tissue only with difficulty. The preparation of current MRT images provides valuable support in these situations. 'The brain can be represented in an enormous variety of ways,' says Dr. Schmidt. 'We can represent anatomy or functional centres, transmission pathways or circulatory problems – and therefore answer many more questions in our discipline than we can with computer tomography.' The precision of the surgical intervention is significantly increased, reducing the risk of neurological damage.
Interplay of action
To achieve this goal, all workflows in the BrainSUITE must be coordinated with one another. An operation starts with the preparation of the patient in the central prep room for neuroanaesthesiology. In the OR, the patient is moved to the OR table, and his or her head is fixed in a frame with an integrated MR coil. This position is held throughout the operation and transfer to the MRT. This is possible due to the design of Trumpf Medical's JUPITER table, in combination with a Myiabi design developed together with Siemens. This makes it possible for the table to be turned into the transfer position manually. The table remote control allows the tabletop to be oriented exactly in the direction of the MRT changer table and this position can be stored in advance. The table moves into its exact position, the integrated bridge board is folded out, and the table must simply be moved onto the MRT rails. Once the tabletop is completely on the MRT table, it stops automatically, releasing the rest of the transfer. 'It's millimetre-exact work, especially for Siemens and Trumpf Medical. After all, the OR column and isocentre of the MRT must not only be same axis in the plan, but in the actual implementation, too,' explains project lead Birzle.
On the OR table, the patient is moved into the magnets. Here, too, safety comes first, since both the anaesthesia and ventilation and infusion tubes must also be carefully transported. These are also the only things that can be moved towards the magnet without influencing it. They do carry electricity, but they are completely shielded. The head coils with their sterile covers are now connected to the MRT. During the scanning process, the entire team leaves the room, controlling everything through a central control unit, even the devices needed for anaesthesia. In the now-electricity-free OR, the nuclear spin can work undisturbed, while the physicians and OR personnel can keep an eye on the patient through a glass window or a room camera. All monitoring signals for anaesthesia can be viewed through a WLAN connection, so that the measurement can be interrupted at any time in emergencies. Afterwards, the patient is moved back into the operating position over the same path – and the surgery can continue.
Safe and efficient
The transfer must take place in as little time as possible, but of course all safety criteria must still be met. That was just one reason the hospital decided on the JUPITER OR table, combined with the Myiabi concept by Siemens and Trumpf Medical. 'We were looking for a solution to transfer the patient as easily and gently as possible from the operating position into the MRT,' explains Dr. Schmidt. In order to achieve navigation precision, it is essential for the patient always to remain in exactly the same position. Another important point: the distance from the table to the magnetic field, so that surgeons and nursing staff can work freely and safely, for instance be able to move around the table. Both of these criteria are met by JUPITER, thanks to the extreme flexibility and precision of its tabletop and the added bridge board. 'We are still in one room – but functionally, we can speak of two different areas which remain separate, the OP area and the MRT area.'
'All in all, the scanning takes about 30 minutes, transfer and all,' says Dr. Schmidt. 'That does extend the time of surgery, but the utility of intraoperative diagnostics compensates for that. If the images show that a tumour hasn't been entirely removed, we can possibly make a new incision – potentially saving the patient a second operation.' Depending on the indication and tumour, the MRT is used two to three times during a surgery. This is usually one preoperative, one intraoperative, and, if residual tumour is present, a second intraoperative scan. Within a few minutes, the software by BrainLAB converts the MRT images into a 3D picture, loading it into the navigation system. Using markers integrated into the head coil, this can be referenced with an infrared camera. Thus the navigation system receives information about where the patient's head is in space, and can provide all the data needed to continue the operation. Using the BrainSUITE NET data management system, the surgeon can use a touchscreen for single-handed control of OR technology like navigation, illumination and ventilation, and call up patient data. He or she can decide exactly what should be displayed on each of the three large flat-panel screens. For instance, the current MRT image on the left, a microscopic image in the middle, and another image sequence on the right, perhaps the preoperative view. 'In principle, the whole thing works like the navigation system in an automobile,' explains Dr. Schmidt. 'You drive – and suddenly you see a new path that the system doesn't know yet. If you could make your own digital recording of that route and feed it into the navigation system, the next time it could display the new street as well. That's the way this system works.' The currently loaded MRT images increase the probability of achieving complete resection – while retaining neurological functional centres.
In all, the physicians in Günzburg have an initial positive conclusion. Despite the additional effort, to date all surgery durations have been under ten hours. 'In comparison, that's very good,' says Dr. Schmidt. 'In neurosurgery, we're used to long durations; in nerve surgery, operations can last even 13 or 14 hours.' Furthermore, the increased precision avoids a second operation in many cases, which in the same location is always associated with increased risk of complications. Simple, safe patient transfer, as well as the fast, high-quality imaging, also contributed to improved working conditions and workflows in the BrainSUITE. 'For the future, we're planning on a load of up to 100 surgeries per year,' says Dr. Schmidt.
The JUPITER OR table also provides increased efficiency with its replaceable tabletop system, because any other Trumpf Medical tabletop also fits on the column. 'That's another advantage, since other operations can also be carried out in this OR – such as an intervertebral disc surgery which must be operated in a prone position,' explains Josef Birzle. 'So it is also a flexibly usable OR. And this is also true because the surgical workspace lies entirely outside the relevant magnetic field, which wouldn't be the case for other table designs. Even non-operational patients can be scanned in the MRT. For that, we use a docking process using a trolley with a tabletop. 'The BrainSUITE is in many aspects simply an integrated functional unit which works due to the precise interplay of all its components,' summarises Josef Birzle. 'That is its biggest advantage.'