Three steps for
creating a 3D image

The right operating table

On an adjustable carbon table top or carbon table top segment, the patient can be optimally posi­tioned for the C-arm’s scan center with respect to height and lateral hori­zon­tal shift. The table top can also be imaged without creating any artifacts.

Special table accessories

For operations on the scull or the elbow or wrist, special oper­at­ing table systems, exten­sions or carbon head holders should be used.

Proper positioning

Positioning aids that will remain in the scan field (such as leg or pelvic supports) also need to be able to be scanned with­out pro­ducing any artifacts. It is always better to remove posi­tioning aids from the scan center in order to allow room for the orbital move­ment. This also permits the dose applied to the patient to be reduced. For oper­a­tions on the cer­vi­cal spine, the patient’s arms should be positioned next to the body.

Use exposure protection

For many appli­ca­tions, a lead apron can also be used for the patient to guar­an­tee opti­mum radiation protection.

Control the contralateral surgical region

For surgical proce­dures involving the lower extrem­ities, as much of the contra­lateral sur­gi­cal region as pos­sible should be removed from the radi­a­tion field. Before sur­gery, it should be checked whether an osteo­syn­thetic or pros­thetic implant has been implanted in this region.

Position the structure to be operated on in the isocenter

For surgical proce­dures involving the upper body (e.g. on the spine), the patient should be posi­tioned as centrally as possible on the oper­at­ing table. For scans of the hip, shoulder or extrem­ities, the side to be oper­ated on should be located opposite the C-arm and should be placed closer to the center of the operating table.

Sterile draping of the surgical field

During the 3D scan, the gener­ator moves below the oper­at­ing table and across the height of the table. For this reason, maximum sterility below the table must be ensured; this can be achieved through proper sterile draping.

Start up the C-arm in good time

In order to avoid unnec­es­sary down time in the oper­at­ing room, the C-arm can already be switched on while the patient is being positioned.

Optimal presettings

Thanks to the C-arm’s indi­vid­ual set­tings to accom­mo­date the patient’s size, the area of appli­ca­tion and the body region to be oper­ated on in the 3D menu, the radi­a­tion, scan and path para­meters are auto­matically selected to ensure opti­mum image quality.

Setting the starting position

To ensure a smooth sur­gi­cal proce­dure, the “Starting posi­tion” menu item should be used to place the C-arm in starting or neutral position.

Proper positioning

The region of interest (ROI) is set with the two vertically stacked and one horizontal laser of the C-arm in the iso­center in an efficient and exposure-free manner. A motorized operating table is partic­ularly helpful for positioning.

Preventing information loss

If a screw or an implant is located exactly in the C-arm’s 3D rotation angle, infor­mation behind the metallic body can be lost (orthogonal effect). Rotating the C-arm by as little as 5 – 10° can bring about successful 3D results.

Collision check

The recon­structed data volume has an edge length of 16 cm. In order to display the sur­gi­cal site in the best possible manner in the iso­center, during the colli­sion check, a 2D image should be taken in both antero­pos­terior and in lateral position. Afterwards, corrections to the patient positioning can be carried out as needed.

Correcting the trajectory

During the collision check of the C-arm for the 3D scan, in the event of a colli­sion with an object, such as the table, it is possible to correct the trajectory in a horizontal direction. This enables optimal adjust­ment of the orbital rotation for the C-arm to the actual condi­tions, without losing the presettings or limiting the scan field.

Breathing stop for better image quality

For spinal oper­a­tions in particular, the patient’s breathing must be stopped in expi­ration for the dura­tion of the 3D scan (approx­i­mately 45 seconds). If this is communi­cated five minutes ahead of time, the patient can be hyper­oxygenated.

Now, the wireless foot­switch is used to start the fully automatic scan from out­side the operating room. The team exits the room and is protected from exposure.