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SURGICAL KNOT TYING MANUAL*United States Surgical, 150 Glover Avenue, Norwalk, Connecticut 06856The Syneture name, logo, and the lines “The Thread Between Science and Healing” are trademarks of Tyco Healthcare Group LP. 2005 Syneture. All rights reserved. MCI 3.05 0M BK000201

SYNETURE Knot Tying ManualRichard F. Edlich, M.D., Ph.D.Distinguished Professor Emeritisof Plastic Surgery and Biomedical EngineeringFounder of DeCamp Burn and Wound Healing CenterUniversity of Virginia Health SystemEditor-in-ChiefJournal of Long-Term Effects of Medical ImplantsDirector of Trauma Prevention, Education and ResearchTrauma Specialists, LLP, Legacy Emanuel HospitalPortland, OregonWilliam B, Long III, M.D.Medical Director, Trauma Specialists, LLPLegacy Emanuel HospitalPortland, ORSyneture is a division of U.S. Surgical/Tyco Healthcare, Norwalk, CT.

acknowledgementsIf this manual heightens only perceptibly students, nurses,nurse practitioners , physician assistants, surgical residentsand surgeon’s interest in the biology of wound closure andinfection, the long years occupied in our search for improvedmethods of wound management would more than fulfill myexpectations. However, another important purpose of thismanual is to honor our colleagues, who collaborated in ourclinical and experimental research investigations. It is aduteous pleasure to acknowledge the great help that I havereceived from Dr. George T. Rodeheaver, Distinguished ResearchProfessor of Plastic Surgery, University of Virginia Health Systemand Dr. John G. Thacker, Vice-Chairman of the Department ofMechanical and Aerospace Engineering, University of Virginia,who have made numerous scientific contributions to our studiesof wound closure. Dr. Thacker and Dr. Rodeheaver are excellentteachers who provide the insight and imagination that solvethe most challenging problems. It is also important to note thatstudies have been undertaken with gifted surgeons and TraumaSpecialist, LLP who have developed a verified Level I TraumaCenter in the Pacific Northwest. Dr. William B. Long III, MedicalDirector of Trauma Specialist LLP of Legacy Emanuel Hospitalhas played an instrumental role in evaluating the performanceof surgical products for trauma care that are used throughoutthe world.table of contentsI.Individualized Self-InstructionII.Introduction2-3III.Scientific Basis for Selection of Sutures1. Nonabsorbable Suture2. Absorbable Suture4-21512IV.Components of a Knotted Suture Loop22-27V.Mechanical Performance1. Knot Slippage2. Knot Breakage3. Suture Cutting Tissue4. Mechanical Trauma28-2930313233VI.Tying Technique1. Instrument Tie2. Hand Tie34-3637-3839-41VII.Essential Elements42-43VIII.Two-Hand Technique1. Square Knot (1 1)2. Surgeon’s Knot Square (2 1)3. Slip Knot (S S)44-5152-6162-69One-Hand Technique1. Square (1 1)70-77Instrument-Tie Technique1. Square Knot (1 1)78-85IX.X.XI.Selection of Suture and Needle ProductsXII.References18687-91

I. individualized self instructionThe root origin of the word education is educare or to anglicize it, edu-care. The meaningof education, therefore, is to care for, to nourish, to cause to grow. This being their ultimateresponsibility, teachers of surgery should be the most responsive component of the instructionsystem. Numerous other pressing clinical and administrative commitments, however, oftenlimit interactions with the medical students, nurses, nurse practitioners physician assistants, surgical residents and surgeons. Consequently, learning difficulties may not be identified.This manual was designed to be a self-instructional teaching aid for the medical student,resident, and surgeon providing an individualized environment of learning. For convenience,each page of this manual has wide margins to accommodate personal thoughts and furtherclarification. This manual is bound in a ring binder so that it lies flat, a prerequisite for anyknot tying manual. The reader should take as little or as much time as needed to digest theinformation and to develop the illustrated psychomotor skills. At the end of this instruction,you should feel considerably more comfortable in understanding the science of tying surgicalknots. More importantly it is our hope that this manual will inspire, motivate, and encouragecreativity and self-direction in your study of the biology of wound repair and infection.1

II. introduction3. Individualized Self InstructionThrough the ages, the tying of knots has played an important role in the life ofman.1 Most of the ancient civilized nations, as well as savage tribes, were accomplished rope makers. Because rope could have served few useful purposes unless itcould be attached to objects by knots, man’s conception of the rope and the knot musthave occurred concomitantly. Knotted ropes played many important roles in theancient world, being used in building bridges and in rigging ships.Because rope and knots have been two of man’s most useful tools since the dawnof history, it is not surprising that they also have symbolic and even magical connotations. It was the custom of Roman brides to wear a girdle tied with a square (reef)knot, which their husbands untied on their marriage night, as an omen of prolificoffspring. Moreover, it was believed that wounds healed more rapidly when thebandages which bound them were tied with a square (reef) knot.This mythology of knots may have contributed to some surgeon’s perception ofsurgical knots more as an art form, than as a science. For those artisans, the useof methods and materials for suturing is usually a matter of habit, guesswork, ortradition.2 This approach to suturing has contributed to a growing concern thatthe knot construction employed by many surgeons is not optimal and that they2use faulty technique in tying knots, which is the weakest link in a tied surgical suture.When the recommended configuration of a knot, ascertained by mechanical performancetests was compared to those used by board-certified general surgeons, only 25% of thesurgeons correctly used the appropriate knot construction.3 Of the 25 gynecologists, mostlydepartment heads, who were polled about their knot tying technique, most were convincedthey they made square knots, even though their knot tying technique resulted in slipknotsthat became untied.4 When a knotted suture fails to perform its functions, the consequencesmay be disastrous. Massive bleeding may occur when the suture loop surrounding a vesselbecomes untied or breaks. Wound dehiscence or incisional hernia may follow knot disruption.As with any master surgeon, he/she must understand the tools of his/her profession. The linkagebetween a surgeon and surgical equipment is a closed kinematic chain in which the surgeon’spower is converted into finely coordinated movements that result in wound closure with theleast possible scar and without infection. The ultimate goal of this linkage the perfection ofthe surgical discipline. This manual has been written for medical students, nurses, nursepractitioners physician assistants, surgical residents and surgeons who view themselvesas scientists cultivating and practicing the science of surgery.3

III. scientific basis for the selection of surgical suturesThere are several different suture materials and needles that provide an accurateand secure approximation of the wound edges. Ideally, the choice of the suturematerial should be based on the biological interaction of the materials employed,the tissue configuration, and the biomechanical properties of the wound. Thetissue should be held in apposition until the tensile strength of the wound issufficient to withstand stress. A common theme of the many reportable investigations is that all biomaterials placed within the tissue damage the host defensesand invite infection. Because surgical needles have a proven role in spreadingdeadly blood borne viral infection, the surgeon must select surgical gloves thatreduce the risk of accidental injuries during surgery.5Important considerations in wound closure are the type of suture, the tyingtechnique, and the configuration of the suture loops. Selection of a surgicalsuture material is based on its biologic interaction with the wound and itsmechanical performance in vivo and in vitro. Measurements of the in vivodegradation of sutures separate them into two general classes.6 Sutures thatundergo rapid degradation in tissues, losing their tensile strength within60 days, are considered absorbable sutures. Those that maintain their tensile4strength for longer than 60 days are nonabsorbable sutures. This terminology issomewhat misleading because even some nonabsorbable sutures (i.e., silk, cottonand nylon) lose some tensile strength during this 60-day interval. Postlethwait 7measured the tensile strength of implanted nonabsorbable sutures during a period oftwo years. Silk lost approximately 50% of its tensile strength in one year and had nostrength at the end of two years. Cotton lost 50% of its strength in six months, butstill had 30-40% of its original strength at the end of two years. Nylon lost approximately 25% of its original strength throughout the two-year observation period.1. NONABSORBABLE SURGICAL SUTURESThe nonabsorbable sutures of Syneture, U.S. Surgical (Div. Tyco Healthcare, Norwalk,CT) can be classified according to their origin. Nonabsorbable sutures made fromnatural fibers are silk sutures. SOFSILK silk sutures are nonabsorbable, sterile, nonmutagenic surgical sutures composed of natural proteinaceous silk fibers calledFibrin. This protein is derived from the domesticated silkworm species Bombyx moriof the family bombycidae. The silk fibers are treated to remove the naturally-occurring sericin gum and braided sutures are available coated uniformly with a special5

III. scientific basis for the selection of surgical sutures (cont'd)wax mixture to reduce capillarity and to increase surface lubricity whichenhances handling characteristics, ease of passage through tissue, and knotrun-down properties. SOFSILK sutures are available colored black withLogwood extract.6Metallic sutures are derived from stainless steel. Modern chemistry hasdeveloped a variety of synthetic fibers from polyamides (nylon), polyesters(Dacron), polyolefins (polyethylene, polypropylene), polytetrafluoroethylene,to polybutester.will facilitate knot rundown and suture passage through the tissue. A new polypropylene suture (SURGIPRO II) has been developed that has increased resistanceto fraying during knot rundown, especially with smaller diameter sutures. Polypropylene sutures are extremely inert in tissue and have been found to retain tensilestrength in tissues for a period as long as two years. Polypropylene sutures are widelyused in plastic, cardiovascular, general, and orthopedic surgery. They exhibit a lowerdrag coefficient in tissue than nylon sutures, making them ideal for use in continuousdermal and percutaneous suture closure.Polypropylene is a linear hydrocarbon polymer that consists of a strand ofpolypropylene, a synthetic linear polyolefin. All polypropylenes begin witha base resin and then go through the following steps: extrusion, drawing,relaxation, and annealing. Each step in the process will influence the ultimatebiomechanical performance of the suture. Biomechanical studies demonstratethat the manufacturing process (i.e., annealing, relaxation) can dramaticallyinfluence the surface characteristics without altering its strength. Changesin the surface characteristics can facilitate knot construction of the suture.Polypropylene sutures (SURGIPRO ) that have a low coefficient of frictionMONOSOF and DERMALON are monofilament sutures composed of the long-chainpolyamide polymers Nylon 6 and Nylon 6.6. While they have a high tensile strengthand low tissue reactivity, they degrade in vivo at a rate of about 12.5% per year byhydrolysis. The pliability characteristics of these sutures permit good handling.Because nylon sutures are more pliable and easier to handle than polypropylenesutures, they are favored for the construction of interrupted percutaneous sutureclosures. However, polypropylene sutures encounter lower drag forces in tissue thannylon sutures, accounting for their frequent use in continuous dermal and percutaneous suture closure. Nylon sutures are also available in a braided construction7

III. scientific basis for the selection of surgical sutures (cont'd)(SURGILON ). These braided nylon sutures are relatively inert in tissue andpossess the same handling and knot construction characteristics as the naturalfiber, silk sutures (SOFSILK ).Polyester sutures (SURGIDAC , TI CRON ) are comprised of fibers of polyethyleneterephthalate, a synthetic linear polyester derived from the reaction of a glycol anda dibasic acid. Polyester sutures were the first synthetic braided suture materialshown to last indefinitely in tissues. Their acceptance in surgery was initially limitedbecause the suture had a high coefficient of friction that interfered with passagethrough tissue and with the construction of a knot. When the sutures were coatedwith a lubricant, polyester sutures gained wide acceptance in surgery. This coatingmarkedly reduced the suture’s coefficient of friction, thereby facilitating knot construction and passage through tissue. The TI-CRON polyester sutures are coatedwith silicone, while the surface lubricant for SURGIDAC is polybutylene adipate.Because some surgeons prefer to tie sutures with a high coefficient of friction,the SURGIDAC sutures are also available without a surface coating.The polybutester suture (NOVAFIL ) is a block copolymer that contains butyleneterephthalate (84%) and polytetramethylene ether glycol terephthalate (16%).8Polybutester suture has unique performance characteristics that may be advantageousfor wound closure.8 This monofilament synthetic nonabsorbable suture exhibits distinctdifferences in elongation compared with other sutures. With the polybutester suture,low forces yield signific