Surgical light suspension: central axis, arms and sizing

The components of a suspension system

A suspension consists of a ceiling plate or cover, a central axis, one or more arms, and brakes or friction joints. Spring arms carry the load of the light head and balance it so that it stays where it is placed. The cable for power, data and control runs inside the arms.

Several arms can share one central axis, so a theatre can carry two surgical lights and one or two monitors on the same ceiling point. The axis also decides how far each arm can rotate, and slip rings allow continuous rotation without twisting cables.

Spring arms, range of motion and braking

Range of motion decides whether the light can reach the field when the table is raised, tilted or turned. SIMEON states that its spring arms offer more than 20 percent greater range of movement than before, from +45° to -75°, which helps procedures performed seated.

Brakes and friction need to hold the light without drifting and be easy to release with one hand. During acceptance testing, move every arm through its full range with a representative load and check for drift, play and noise. This is also part of annual inspection, see surgical light preventive maintenance.

Sizing for lights and monitors

The first number to check is the maximum load per arm. The MZ Liberec SPR system lists up to 28 kg per arm for the SPR 10, up to 12 kg per arm for the SPR 11, and an SPR 23 for examination and small surgical lights; swivel arm length is 500 to 1,100 mm, and rotation is 360 degrees, or 330 degrees with a monitor.

Add the weight of the light head, camera, handle accessories and monitor, and then allow a margin. A heavy monitor on a long arm creates leverage at the axis, so the reach and the load must be considered together, not separately.

• Weight of each device plus cables and accessories.
• Reach to each corner of the work area with the table in several positions.
• Height under the arm in the lowest position, so that it clears staff and the laminar airflow panel.
• Ceiling structure and the ceiling cover size, for example 400 x 400 or 580 x 580 mm on SPR.

Examples from our manufacturers

SIMEON Sim.FLEX takes up to four arms on one central axis, with arm lengths up to 2,000 mm for hybrid ORs, and further arms can be added after installation. Sim.SCREEN holds monitors up to 32 inches. See the Sim.FLEX overview for details.

The Lojer Q-Flow suspension family has SOLO in mobile, wall and ceiling versions and DUO, TRIO and QUAD as ceiling-mounted multi-arm configurations. QUAD has four horizontally swivelling arms for a complete lighting and display set-up in a digital theatre. Ceiling tubes of 50, 65 or 110 mm are listed depending on the model.

Planning mistakes to avoid

The most common mistake is ordering the lights first and the suspension later. The ceiling load, the position of the axis in relation to the table, the laminar airflow panel and the other booms all need to be fixed together. A layout drawn on paper should be checked against the real room and the real table positions.

Another mistake is to use a minimum arm configuration that cannot be extended. If a camera or an extra monitor is planned in two years, choose a modular system. For the wider picture on booms see operating room lights and booms.

Next steps

Send us the room plan, the table positions and the devices you plan to carry. Beckfinity can propose a suspension layout with the manufacturer and arrange installation. Request a quote or a consultation from our specialists.