Operation Table (Operating Table) - Complete Overview

1. Structure

• Base: A heavy, broad column-mounted or pedestal base that provides stability and prevents tipping when the table is tilted or loaded. Many bases contain the hydraulic pump/motor unit and battery packs.
• Column (pedestal): A single or double central column that supports the tabletop and houses the lift mechanism (hydraulic cylinder or electro-mechanical screw drive). It allows vertical height adjustment.
• Tabletop (patient platform): Made of multiple radiolucent sections - head section, back/torso section, seat section, and leg section(s) - each independently articulating. Sections can be added, removed, flexed, or split to allow C-arm/image intensifier access and varied surgical positions.
• Side rails: Universal rails running the length of the tabletop used to attach accessories (arm boards, stirrups, retractor holders, anesthesia screens, positioning aids).
• Mattress/pads: Removable, radiolucent, pressure-relieving cushions covering each section.
• Locking and articulation joints: Allow Trendelenburg/reverse Trendelenburg tilt, lateral tilt, flexion/extension (jack-knife), and section-by-section angulation.
• Castors/wheels with brakes: For mobility within the OT and locking during the procedure (in mobile models).
• Control unit: Hand pendant, foot pedal, or side-mounted panel for hydraulic/electric operation, often with a battery backup.

2. Materials Used in Fabrication

3. Advantages of These Materials

• Stainless steel (base, frame, rails): Corrosion resistant (withstands repeated disinfectant/antiseptic exposure), non-reactive, durable, easy to sterilize/wipe clean, resistant to rust and staining, high tensile strength to bear patient weight and dynamic loads during tilting.
• Radiolucent carbon fiber/composite tabletop: Transparent to X-rays so fluoroscopy and intraoperative imaging can be done without moving the patient; lightweight yet strong; does not corrode.
• High-density PU foam with PVC/leather cover: Seamless, impervious surface prevents fluid/blood absorption, reducing infection risk; fire-retardant for OT safety (electrocautery use); provides pressure distribution to reduce intraoperative pressure injuries; easy to wipe and disinfect between cases.
• ABS/powder coating on covers: Chemical resistant, smooth non-porous finish that resists microbial colonization and is easy to clean.

4. Care, Maintenance, and Uses

• Clean and disinfect the tabletop, mattress, and rails after every case with a hospital-grade disinfectant; avoid harsh abrasives that scratch the stainless steel or crack the radiolucent top.
• Inspect mattresses/cushions periodically for cracks or tears (a torn cover risks fluid ingress and cross-contamination).
• Check hydraulic fluid levels and look for leaks at seals/cylinders on hydraulic tables; top up or replace hydraulic oil as per the manufacturer's schedule.
• Lubricate moving joints, locking mechanisms, and castor wheels regularly to prevent stiffness or squeaking.
• For electric/electro-hydraulic tables, check battery charge status daily and keep it on charge when not in use; test the backup battery function periodically in case of mains power failure during surgery.
• Verify that all locking levers, section joints, and safety straps engage firmly before every use.
• Schedule periodic preventive maintenance/calibration by biomedical engineering staff, including load testing, checking of tilt-angle accuracy, and electrical safety testing (earth leakage, insulation).
• Keep control pendant cables, foot switches, and connectors protected from spills to prevent short circuits.

5. Controls

A. Hydraulic System

• Principle: Uses Pascal's law - a hydraulic pump (manually operated foot pump or motor-driven pump) pressurizes hydraulic oil, which drives a piston/cylinder to raise, lower, or tilt the tabletop.
• Components: Reservoir (oil tank), pump, hydraulic cylinder(s), control valves, pressure release valve, and connecting tubing.
• Operation: Pressing a foot pedal or lever opens a valve directing pressurized oil into the lift cylinder, raising the table; releasing the pedal in the opposite direction opens a return valve, allowing oil to flow back and lower the table smoothly.
• Advantages: Simple, reliable, functions even during power failure (manual/foot-pump models), smooth and stepless movement, capable of bearing heavy loads without motor strain.
• Limitations: Requires manual effort in purely mechanical models, possible oil leakage over time, slower than electric actuation.

B. Electrical System

• Principle: An electric motor (often paired with a hydraulic pump - "electro-hydraulic" system) or a screw-drive mechanism moves the table sections on command from push-button controls.
• Components: Mains power supply with a rechargeable battery backup (essential for OT safety during power cuts), motor/actuator, control pendant or foot switch, microprocessor-based control panel, limit switches for safety cut-off at maximum/minimum range.
• Operation: Push-button or joystick control on a hand pendant/foot pedal sends a low-voltage signal to the control unit, which activates the motor/pump to move the selected section (height, back, leg, Trendelenburg, tilt) until the button is released or a limit switch is triggered.
• Advantages: Precise, effortless, multi-directional simultaneous movements, memory/preset position functions in advanced models, battery backup ensures function during mains failure.
• Safety features: Emergency stop button, isolation from mains during patient contact with electrocautery (to prevent stray current burns), and interlocks preventing movement when not required.