Category Archives: Surgical Instruments

Optimal Bone Saw Blade Design

[Note:  This article was initially published in Medco Forum, Volume II, Number 5.  It is being republished with permission from Medco Forum.]

All surgical oscillating blades are not created equal.  There may be many similarities between blades, but the performance characteristics can be significantly different.  Orthopaedic surgeons require a reliable, effective means of making bone resections that enhance surgical control with the same feel every time.  As less-invasive reconstructive procedures evolve and biologic fixation advances, surgeons will need bone resection technology to minimize the possibility of injuring surrounding soft tissue structures as well as the living bone supporting the implants.  Synvasive Technology Inc.’s STABLECUT oscillating blade technology represents a substantial breakthrough in the science of powered bone resection.  STABLECUT is favored by reconstructive knee surgeons as a means of transforming the function of an oscillating blade from an “attachment” into a reconstructive tool, aimed at improving the surgical control of bone removal required to resurface an articulating joint.

Traditional oscillating blades have their teeth oriented on an arc, and when cutting bone, all of the teeth engage at once as the blade progresses and swings through its constantly reversing arc of motion.  This arc-shaped engagement, accentuated by the oscillating motion of the powered hand-piece, creates two primary influences that adversely affect performance.  First, as the blade direction is changed, the contact point of the teeth moves off center.  This reduces hand-piece control as the blade reacts to off-center contact, causing it to deflect right or left of the surgeon’s intended path.  Secondly, the resection path becomes matched to the arc-shaped excursion, preventing the teeth from effectively evacuating bone chips, which build up in front of the advance blade and generate friction.  This limits debris removal and increases both deflection and heat transferred to the adjacent bone tissue, increasing the potential risk cell damage and necrosis can pose to bone healing and biologic fixation.  All of these effects collectively raise the risk of collateral soft-tissue damage and inaccurate cuts.

The patented perpendicular (90 degree) teeth configuration on a STABLECUT blade establishes a centered back-and-forth sawing action within the fixed arc of powered oscillation.  It creates a stabilizing “high spot” in the center of the cut as the blade engages the bone.  This “high spot” makes the blade exceptionally stable, enabling the surgeon to achieve a higher level of precision as the controlled blade advances through a cut and around soft-tissue structures.  Debris is also ejected more efficiently, creating less friction, to enhance tissue care surrounding a resection.  Anthony K. Hedley, MD, Chairman of Orthopaedic Surgery, St. Luke’s Hospital (Phoenix, AZ), uses STABLECUT blades exclusively.  Dr. Hedley finds that “the STABLECUT blades are well designed in terms of tooth design, which provides for very precise cuts.  When a total knee replacement procedure is performed, it is important to use a straight blad that had no arc, so as to avoid loss of control when making cuts.  STABLECUT blades help avoid dimensional changes to the template bone that result in loose fitting components.  This is especially important when implanting press fit prostheses.”

Directional control and reduced temperature are important enablers of MIS total and unicompartmental knee replacement.  Stability of the saw blade greatly improves safety and precision as surgical exposures are reduced.  According to David Dalury, MD, of St. Joseph’s Hospital (Towson, MD), “I am impressed with the reproducibility and accuracy of STABLECUT.  These blades give me the confidence that I will be able to resect the template bone accurately during bone-conserving unicompartmental procedures.  The fact that you can be more precise in cuts means that you will be less likely to damage surrounding tissues – a definite enhancement in patient safety.”

STABLECUT bone resection technology is advancing reconstructive surgery today and will continue into the future as the interest in reduced-exposure reconstructions increases.  The inherent accuracy of STABLECUT technology will be particularly evident as computer-aided reconstructions grow.  STABLECUT blades maintain better directional control during the cutting process and are less likely to “kick-out” of the intended track.  The net benefit is a more accurate cut with less buildup of heat, to improve tissue care.  According to Mike Fisher, President and CEO of Synvasive Technology, Inc., “Our surgeon customers didn’t ask us to reinvent the powered oscillating hand-piece, rather to enhance the blade’s cutting performance and improve their confidence in the OR.”

Since its founding in 1990, Synvasive Technology, Inc. has steadily grown to become one of the most innovative leaders in orthopaedic resection technology.  Synvasive develops, manufactures, and distributes patented and proprietary instruments with a vision to advance and enhance the success of reconstructive procedures.  The company operates in accordance with the ISO 13485 quality management system and European medical device directive.  Synvasive’s products are marketed through a worldwide network of distributors and major orthopaedic companies, as well as a professional team of internal sales and customer service representatives.

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