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FMsealer Open Shear

FMsealer Open Shears

Domain Surgical’s FMsealer Open Shears are a multi-functional vessel sealing instrument that uses ferromagnetic technology to reliably seal and divide tissue with minimal impact to adjacent healthy tissue.

Enhanced Patient Safety

FMsealer Open Shears provides reliable vessel sealing and minimized thermal impact to healthy tissue without passing electrical current through tissue; eliminating stray current, reducing risk of capacitive coupling, and making it safe to operate near metal staples, clips, and instruments.

Robust Vessel Sealing

FMsealer Open Shears seals vessels up to 7 mm in diameter, including lymphatics, with reliability and performance comparable to industry-leading vessel sealing instruments.1


Speed and Efficiency

50% faster transection of vascular tissue bundles than bipolar and ultrasonic devices.2 Distinct activation modes have been optimized for different desired tissue interaction.


Precise control of heat with 15% less lateral thermal spread than competitive instruments,2 and less desiccation and char formation than competitive instruments.1

Transhiatal Esophagogastrectomy Using FMX Instruments

Domain Surgical’s FMwand and FMsealer Open Shears are used to perform a transhiatal esophagogastrectomy.

Not All Energy is the Same

Energy-based vessel sealing instruments use a combination of heat, friction, and compression force to seal and divide tissue. Each source of energy presents unique operational and safety considerations.

Technology Comparison


  • Electrical current passes through the tissue clamped between opposing electrodes, creating heat and fusing the tissue together.
  • After the vessel is sealed, a mechanical blade is used to divide tissue.
  • Bipolar devices produce a high amount of lateral thermal spread1, posing risk of injury to adjacent tissue structures, and presenting a risk of stray electrical current, arcing, or sparking.


  • Heat is created through vibrational friction of the active blade, sealing and dividing the tissue clamped in the jaw.
  • Tissue is simultaneously sealed and divided.
  • The active jaw of ultrasonic devices emanates heat in all directions. Contacting metal or plastic instruments, staples, or clips while activated can damage the blade, making it unusable.


  • Thermal energy is directed from the active jaw to the inactive jaw, uniformly fusing tissue together.
  • Both “seal only” and “seal & divide” activation modes are available.
  • Ferromagnetic instruments provide reliable vessel sealing1 and less thermal spread than competitive devices1, without passing electrical current through tissue; eliminating stray current, reducing risk of capacitive coupling, providing safe operation around metal staples and clips.2

Clinical Outcomes That Truly Make a Difference

Reliable Vessel Sealing

FMsealer Open Shears deliver effective vessel sealing with reliability and performance comparable to or better than industry leading vessel sealing instruments, even when sealing larger vessels ( > 5 mm in diameter).1

Sealing Reliability Study

Porcine arteries measuring 5 mm in diameter were sealed in a controlled laboratory setting using LigaSure™, Harmonic®, and FMsealer open vessel sealing instruments. The percentage of overall seals that resulted in burst pressures above 240 mmHg are shown below.1

FMsealer Open Shears Reliability
Burst Pressure Study

Porcine arteries measuring 5 mm in diameter were sealed using LigaSure, Harmonic, and FMsealer open vessel sealing instruments. Each vessel was sealed, divided, and pressurized using an automated inflation system until the seal failed. Average burst pressure results in mmHg are shown below.1

FMsealer Open Shears Burst Pressure

Speed and Efficiency

FMsealer Open Shears provide unmatched speed and efficiency when transecting through vascular tissue bundles.

Transection Speed Test

Speed tests were performed using LigaSure, Harmonic, and FMsealer open vessel sealing instruments. A 10 cm section of porcine mesentery was measured and marked prior to transection. Each instrument was used to seal and divide pre-measured segments. Multiple rounds were completed with each instrument, and the average time to complete each 10 cm transection are shown below.2

FMsealer Open Shears Burst Pressure

Precision, Predictability, and Control

FMsealer Open Shears seal and divide tissue with a predictable thermal effect, producing less lateral thermal spread than competitive bipolar and ultrasonic vessel sealing instruments.1 FMsealer is gentler on healthy surrounding tissue, creating less tissue desiccation and char formation during use.1

Lateral Thermal Spread Study

Porcine arteries measuring 5 mm in diameter were sealed and divided using Harmonic and FMsealer open vessel sealing instruments. After sealing and dividing, each artery was harvested. HE staining and histologic assessment of lateral thermal spread was performed by an independent reviewer. Lateral thermal spread was determined to be the maximum distance thermal injury extends laterally from the edge of the instrument.

FMsealer Open Shears Thermal Injury
FMsealer Open Shears Histology

Histologic analysis of comparative seals using a Harmonic Focus (above left) and FMsealer Open Shears (above right) in porcine arteries. Black lines indicate measurements of thermal damage.

Activation Modes

FMsealer offers multiple power settings and activation modes, each optimized for a different desired tissue interaction.

High power seal & divide mode: Used to quickly seal & divide vascular tissue bundles, membranes, and small vessels (< 2mm in diameter*).

Seal & divide mode: Used to seal & divide large vessels (> 2 mm in diameter*) with single button activation.

Seal only mode: Used to seal large vessels (> 2 mm in diameter*). If desired, vessel can then be divided by activating the FMmax button.

* Based on surgeon experiences and feedback

FMsealer Open Shears

Design Features

As with all FMX surgical instruments, no electrical current passes through the patient, and it is safe to use around metal devices, staples, and clips. The curved, non-stick jaws are over 30% longer than Harmonic Focus® and LigaSure™ small jaw. Ferromagnetic heating can be activated while compressing the jaws to seal and divide vascular tissue bundles. FMsealer incorporates a patented active cooling system that ensures localization of heat in the jaws and provides rapid cool down following deactivation.

FMX Power Modules

FMX Power Modules connect the FMsealer to the FMX Generator and intelligently manage communication between each component within the system. FMX Power Modules are available in both reusable and single-use disposable configurations. The FMX Reusable Power Module (left) can be autoclave resterilized for use in up to 100 procedures. The FMX Disposable Power Module (right) is single-use only and is discarded following each surgical procedure.

FMX Power Modules

Related Downloads and Additional Resources

Setup is Incredibly Simple

The FMX Ferromagnetic Surgical System combines state-of-the-art surgical technology with unparalleled ease-of-use. Prepare FMX instruments for use by following these simple steps:


Plug the FMX Power Module into the front panel of the FMX Generator



Snap the power module into the back of the FMX instrument




Set the power settings on the generator and the system is ready


  1. Ferromagnetic Heating for Vessel Sealing and Division, Jenwood Chen, MD, Preston K. Manwaring, MSEE, PhD, Robert R. Scott, BSME, Kim H. Manwaring, MD, Robert E. Glasgow, MD, Surgical Innovation, Vol 22, Issue 4, pp. 329 – 337
  2. Internal data on file

Need More Information?

Our customer service team is available to answer any questions that you may have, or to schedule an in-office demonstration of our advanced-energy surgical technologies.